News

Adaptive strategies of sponges to deoxygenated oceans

Abstract.

"Ocean deoxygenation is one of the major consequences of climate change. In coastal waters, this process can be exacerbated by eutrophication, which is contributing to an alarming increase in the so-called ‘dead zones’ globally. Despite its severity, the effect of reduced dissolved oxygen has only been studied for a very limited number of organisms, compared to other climate change impacts such as ocean acidification and warming. Here, we experimentally assessed the response of sponges to moderate[...]".

 

Source: Wiley Online Library 
Authors: Valerio Micaroni et al.
DOI: https://doi.org/10.1111/gcb.16013

Read the full article here.


Rapid ecosystem-scale consequences of acute deoxygenation on a Caribbean coral reef

Abstract.

"Loss of oxygen in the global ocean is accelerating due to climate change and eutrophication, but how acute deoxygenation events affect tropical marine ecosystems remains poorly understood. Here we integrate analyses of coral reef benthic communities with microbial community sequencing to show how a deoxygenation event rapidly altered benthic community composition and microbial assemblages in a shallow tropical reef ecosystem. Conditions associated with the event precipitated coral bleaching and mass mortality, causing a 50% loss of live coral and a shift in the benthic community that persisted a year later. Conversely, the unique taxonomic and functional profile of hypoxia-associated microbes rapidly reverted to a normoxic assemblage[...]".

 

Source: Nature Communications
Authors: Maggie D. Johnson et al.
DOI: https://doi.org/10.1038/s41467-021-24777-3

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Fate of floating plastic debris released along the coasts in a global ocean model

Abstract.

"Marine plastic pollution is a global issue, from the shores to the open ocean. Understanding the pathway and fate of plastic debris is fundamental to manage and reduce plastic pollution. Here, the fate of floating plastic pollution discharged along the coasts is studied by comparing two sources, one based on river discharges and the other on mismanaged waste from coastal populations, using a Lagrangian numerical analysis in a global ocean circulation model. About 1/3 of the particles end up in the open ocean and 2/3 on beaches[...]"

 

Source: Science Direct
Authors: Fanny Chenillat et al.
DOI: https://doi.org/10.1016/j.marpolbul.2021.112116

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A committed fourfold increase in ocean oxygen loss

Abstract.

"Less than a quarter of ocean deoxygenation that will ultimately be caused by historical CO2 emissions is already realized, according to millennial-scale model simulations that assume zero CO2 emissions from year 2021 onwards. About 80% of the committed oxygen loss occurs below 2000 m depth, where a more sluggish overturning circulation will increase water residence times and accumulation of respiratory oxygen demand. According to the model results, the deep ocean will thereby lose more than 10% of its pre-industrial oxygen content even if CO2 emissions and thus global warming[...]".

 

Source: Nature Communications
Authors: Andreas Oschlies
DOI: https://doi.org/10.1038/s41467-021-22584-4 

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In oceanography, acoustics and hydrodynamics: An extended coupled (2+1)-dimensional Burgers system

Abstract.

"In oceanography, acoustics and hydrodynamics, people pay attention to the Burgers-type equations for different wave processes, one of which is an extended coupled (2+1)-dimensional Burgers system hereby under investigation. Based on the scaling transformation, Bell polynomials, Hirota operators and symbolic computation, we structure out two hetero-Bäcklund transformations, each of which to a solvable linear partial differential[...]"

 

Source: Science Direkt
Authors: Xin-YiGao et al.
DOI: https://doi.org/10.1016/j.cjph.2020.11.017

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Shallow marine ecosystem collapse and recovery during the Paleocene-Eocene Thermal Maximum

Abstract.

"The Paleocene-Eocene Thermal Maximum (PETM), the most well-studied transient hyperthermal event in Earth history, is characterized by prominent and dynamic changes in global marine ecosystems. Understanding such biotic responses provides valuable insights into future scenarios in the face of anthropogenic warming. However, evidence of the PETM biotic responses is largely biased towards deep-sea records, whereas shallow-marine evidence remains scarce and elusive. Here we investigate a shallow-marine microfaunal record from Maryland, eastern United States, to comprehensively document the shallow-marine biotic response to the PETM. We applied birth-death modeling to estimate the local diversity dynamics[...]"

 

Source: Elsevier
Authors: Skye Yunshu Tian  et al.
DOI: https://doi.org/10.1016/j.gloplacha.2021.103649

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Microplastics pollution in the ocean: Potential carrier of resistant bacteria and resistance genes

Abstract.

"Microplastics pollution in marine environments is concerning. Microplastics persist and accumulate in various sections of the ocean where they present opportunity for micropollutant accumulation and microbial colonisation. Even though biofilm formation on plastics was first reported in the 1970's, it is only in recent years were plastic associated biofilms have gained research attention. Plastic surfaces pose a problem as they are a niche ready for[...]"

 

Source: Science Direct
Authors: K.S.Stenger et al.
DOI: https://doi.org/10.1016/j.envpol.2021.118130

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Fifty Year Trends in Global Ocean Heat Content Traced to Surface Heat Fluxes in the Sub-Polar Ocean

Abstract.

"The ocean has absorbed approximately 90% of the accumulated heat in the climate system since 1970. As global warming accelerates, understanding ocean heat content changes and tracing these to surface heat input is increasingly important. We introduce a novel framework by organizing the ocean into temperature-percentiles from warmest to coldest, allowing us to trace ocean temperature changes to changes[...]"

 

Source: AGU- Advancing Earth And Space Science
Authors: Taimoor Sohail et al.
DOI: https://doi.org/10.1029/2020GL091439

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Paleocene-Eocene volcanic segmentation of the Norwegian-Greenland seaway reorganized high-latitude ocean circulation

Abstract.

"The paleoenvironmental and paleogeographic development of the Norwegian–Greenland seaway remains poorly understood, despite its importance for the oceanographic and climatic conditions of the Paleocene–Eocene greenhouse world. Here we present analyses of the sedimentological and paleontological characteristics of Paleocene–Eocene deposits (between 63 and 47 million years old) in northeast Greenland, and investigate key unconformities and volcanic facies observed through seismic reflection imaging in offshore basins.[...]"

 

Source: Communications Earth & Environment
Authors: Jussi Hovikoski et al.
DOI: https://doi.org/10.1038/s43247-021-00249-w

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Impacts of Ocean Currents on the South Indian Ocean Extratropical Storm Track through the Relative Wind Effect

Abstract.

"This study examines the role of the relative wind (RW) effect (wind relative to ocean current) in the regional ocean circulation and extratropical storm track in the south Indian Ocean. Comparison of two high-resolution regional coupled model simulations with and without the RW effect reveals that the most conspicuous ocean circulation response is the significant weakening of the overly energetic anticyclonic standing eddy off Port Elizabeth, South Africa, a biased feature ascribed to upstream retroflection of the Agulhas Current (AC).[...]"

 

Source: AMS- American Meteorological Sciety 
Authors: Hyodae Seo et al.
DOI: https://doi.org/10.1175/JCLI-D-21-0142.1

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Ocean currents as a potential dispersal pathway for Antarctica’s most persistent non-native terrestrial insect

Abstract.

"The non-native midge Eretmoptera murphyi is Antarctica’s most persistent non-native insect and is known to impact the terrestrial ecosystems. It inhabits by considerably increasing litter turnover and availability of soil nutrients. The midge was introduced to Signy Island, South Orkney Islands, from its native South Georgia, and routes of dispersal to date have been aided by human activities, with little known about non-human-assisted methods of dispersal. This study is the first to determine the potential for dispersal of a terrestrial invertebrate species in Antarctica by combining physiological sea water tolerance data with quantitative assessments[...]"

 

Source: Polar Biology
Authors: Jesamine C. Bartlett  et al.
DOI: https://doi.org/10.1007/s00300-020-02792-2

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The Thermodynamic Controls on Sulfide Saturation in Silicate Melts with Application to Ocean Floor Basalts

Abstract.

"A thermodynamic model to calculate the sulfide content at sulfide saturation or SCSS of basaltic and intermediate composition silicate melts has been built from four independently measurable thermodynamic entities, namely the standard state Gibbs free energy of the saturation reaction, the “sulfide capacity”, and the activities of FeO in[...]"

 

Source: AGU- Advancing Earth and Space Science 
Authors: Daniel R. Neuville et al.
DOI: https://doi.org/10.1002/9781119473206.ch10

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Recent Developments in Oxygen Minimum Zones Biogeochemistry

New Research Topic: Recent Developments in Oxygen Minimum Zones Biogeochemistry

"Oxygen minimum zones (OMZs) play a key role in carbon, nitrogen and other elemental cycles, and directly impact climate dynamics by influencing air-sea fluxes of the potent greenhouse gases methane and nitrous oxide. Oxygen concentrations, catalyze specialized micro-organisms to regulate chemical fluxes, which are critical for ecosystem functioning. The degree of deoxygenation in the OMZs vary from hypoxic in the tropical Atlantic Ocean to functionally anoxic in the eastern tropical Pacific Ocean and the northern Indian Ocean.[...]"

 

Source: Frontiers
Read articles here.

 


Effect of environmental history on the habitat-forming kelp Macrocystis pyrifera responses to ocean acidification and warming: a physiological and mol

Abstract.

"The capacity of marine organisms to adapt and/or acclimate to climate change might differ among distinct populations, depending on their local environmental history and phenotypic plasticity. Kelp forests create some of the most productive habitats in the world, but globally, many populations have been negatively impacted by multiple anthropogenic stressors. Here, we compare the physiological and molecular responses to ocean acidification (OA) and warming (OW) of two populations of the giant kelp[...]"

 

Source: Nature Scientific Reports
Authors: Pamela A. Fernández et al.
DOI: https://doi.org/10.1038/s41598-021-82094-7

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Constraint on net primary productivity of the global ocean by Argo oxygen measurements

Abstract.

"The biological transformation of dissolved inorganic carbon to organic carbon during photosynthesis in the ocean, marine primary production, is a fundamental driver of biogeochemical cycling, ocean health and Earth’s climate system. The organic matter created supports oceanic food webs, including fisheries, and is an essential control on atmospheric carbon dioxide levels. Marine primary productivity is sensitive to changes due to climate forcing, but observing the response at the global scale[...]"

 

Source: Nature Geoscience 
Authors: Kenneth S. Johnson et al.
DOI: https://doi.org/10.1038/s41561-021-00807-z

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Transferring Complex Scientific Knowledge to Useable Products for Society: The Role of the Global Integrated Ocean Assessment and Challenges in the

Effective Delivery of Ocean Knowledge

Abstract.

"The ocean provides essential services to human wellbeing through climate regulation, provision of food, energy and livelihoods, protection of communities and nurturing of social and cultural values. Yet despite the ocean’s key role for all life, it is failing as a result of unsustainable human practices. The first global integrated assessment of the marine environment, produced by the United Nations under The Regular Process for Global Reporting and Assessment of the State of the Marine Environment, including Socioeconomic Aspects (the World Ocean Assessment), identified an overall decline in ocean health. The second assessment, launched in April 2021, although recognising some bright spots and improvements, stresses ongoing decline in the ocean[...]"

 

Source: Frontiers
Authors: Karen Evans et al. 
DOI: https://doi.org/10.3389/fenvs.2021.626532

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Oxygen loss in fjords, coastal areas, and open ocean systems

Abstract.

"Loss of oxygen and expansion of oxygen depleted environments have been witnessed in both coastal and open-ocean systems since the middle of the 20th century, and ocean modelling predicts continuing decease by the year 2100. Oxygen depletion occurs thus during the same time epoch as global warming. Increased knowledge on how and why oxygen varies in space and time shapes the biogeochemical and ecological structure of marine systems and will be needed for future predictions of marine productivity. In coastal systems deoxygenation is also linked to human activities that lead to increased loadings of nutrients and organic matter, and to regional effects of climate induced changes in wind and precipitation patterns[...]"

 

Source: BJERKNES CENTRE
Authors: Anne Gro Vea Salvanes et al.
 

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Low oxygen levels can help to prevent the detrimental effect of acute warming on mitochondrial efficiency in fish

Abstract.

"Aerobic metabolism of aquatic ectotherms is highly sensitive to fluctuating climates. Many mitochondrial traits exhibit phenotypic plasticity in response to acute variations in temperature and oxygen availability. These responses are critical for understanding the effects of environmental variations on aquatic ectotherms' performance. Using the European seabass, Dicentrarchus labrax, we determined the effects of acute warming and deoxygenation in vitro on mitochondrial respiratory capacities and mitochondrial[...]"

 

Source: The Royal Society Publishing 
Authors: Elisa Thoral et al.
DOI: https://doi.org/10.1098/rsbl.2020.0759

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More than 1000 rivers account for 80% of global riverine plastic emissions into the ocean

Abstract.

"Plastic waste increasingly accumulates in the marine environment, but data on the distribution and quantification of riverine sources required for development of effective mitigation are limited. Our model approach includes geographically distributed data on plastic waste, land use, wind, precipitation, and rivers and calculates the probability for plastic waste to reach a river and subsequently the ocean. This probabilistic approach highlights regions that are likely to emit plastic into the ocean. We calibrated our model using recent field observations[...]".

 

Source: Science Advances 
Authors: LOURENS J. J. MEIJER et al.
DOI: 10.1126/sciadv.aaz5803

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The soundscape of the Anthropocene ocean

Abstract.

"Oceans have become substantially noisier since the Industrial Revolution. Shipping, resource exploration, and infrastructure development have increased the anthrophony (sounds generated by human activities), whereas the biophony (sounds of biological origin) has been reduced by hunting, fishing, and habitat degradation. Climate change is affecting geophony (abiotic, natural sounds). Existing evidence shows that anthrophony affects marine animals[...]".

 

Source: Science
Authors: Carlos M. Duarte et al.
DOI: 10.1126/science.aba4658

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System controls of coastal and open ocean oxygen depletion

Abstract.

"The epoch of the Anthropocene, a period during which human activity has been the dominant influence on climate and the environment, has witnessed a decline in oxygen concentrations and an expansion of oxygen-depleted environments in both coastal and open ocean systems since the middle of the 20th century. This paper provides a review of system-specific drivers of low oxygen in a range of case studies representing marine systems in the open ocean, on continental shelves, in enclosed seas[...]".

 

Source: Science Direct
Authors: Grant C. Pitcher
DOI: https://doi.org/10.1016/j.pocean.2021.102613

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High spatial resolution global ocean metagenomes from Bio-GO-SHIP repeat hydrography transects

Abstract.

"Detailed descriptions of microbial communities have lagged far behind physical and chemical measurements in the marine environment. Here, we present 971 globally distributed surface ocean metagenomes collected at high spatio-temporal resolution. Our low-cost metagenomic sequencing protocol produced 3.65 terabases of data, where the median number of base pairs per sample was 3.41 billion. The median distance between sampling stations was 26 km[...]"

 

Source: Scientific Data
Authors: Alyse A. Larkin et al
DOI: https://doi.org/10.1038/s41597-021-00889-9

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Reconstructing the Preindustrial Coastal Carbon Cycle Through a Global Ocean Circulation Model: Was the Global Continental Shelf Already Both Autotrop

Abstract.

"The contribution of continental shelves to the marine carbon cycle is still poorly understood. Their preindustrial state is, for one,                                                              essentially unknown, which strongly limits the quantitative assessment of their anthropogenic perturbation. To date, approaches developed to investigate and quantify carbon fluxes on continental shelves have strongly simplified their physical and biogeochemical features. In this study, we enhance the global ocean biogeochemistry model HAMburg Ocean Carbon Cycle by[...]"

 

Source: AGU- Advancing Earth and Space Science 
Authors: Fabrice Lacroix et al.
DOI: https://doi.org/10.1029/2020GB006603

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Impacts of hypoxic events surpass those of future ocean warming and acidification

Abstract.

"Over the past decades, three major challenges to marine life have emerged as a consequence of anthropogenic emissions: ocean warming, acidification and oxygen loss. While most experimental research has targeted the first two stressors, the last remains comparatively neglected. Here, we implemented sequential hierarchical mixed-model meta-analyses (721 control–treatment comparisons) to compare the impacts of oxygen conditions associated with the current and continuously intensifying hypoxic events (1–3.5 O2 mg l−1) with those experimentally yielded by ocean warming (+4 °C) and acidification (−0.4 units) conditions[...]"

 

Source: Nature Ecology & Evolution 
Authors: Eduardo Sampaio et al.
DOI: https://doi.org/10.1038/s41559-020-01370-3

Read the full article here.


Ocean acidification may slow the pace of tropicalization of temperate fish communities

Abstract.

"Poleward range extensions by warm-adapted sea urchins are switching temperate marine ecosystems from kelp-dominated to barren-dominated systems that favour the establishment of range-extending tropical fishes. Yet, such tropicalization may be buffered by ocean acidification, which reduces urchin grazing performance and the urchin barrens that tropical range-extending fishes prefer. Using ecosystems experiencing natural warming and acidification, we show that ocean acidification could buffer warming-facilitated[...]"

 

Source: Nature Climate Change
Authors: Ericka O. C. Coni et al.
DOI: https://doi.org/10.1038/s41558-020-00980-w

Read the full article here.


Bacteriohopanepolyols signature in sediments of the East China Sea and its indications for hypoxia and organic matter sources

Abstract.

"The bacterial biomarker group of bacteriohopanepolyols (BHPs) has shown a significant potential to track terrestrial inputs and to respond to environmental changes. A total of 12 BHPs were detected in surface sediments of the East China Sea (ECS), with the contents of 3.79–361 μg/g TOC. The spatial distribution patterns and correlation analyses of bacteriohopanetetrol (BHT) and soil marker BHPs in sediments of the ECS indicate that they were mainly derived from marine autochthonous and terrestrial sources[...]"

 

Source: Science Direct
Authors: Meiling Yin et al.
DOI: https://doi.org/10.1016/j.orggeochem.2021.104268

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Effect of dissolved oxygen and hydrogen on the stress corrosion cracking behavior of alloy 600 in high temperature water

Abstract.

"The stress corrosion cracking behavior of alloy 600 was studied in high temperature water at 288°C to 360°C. The effects of dissolved oxygen (DO) and dissolved hydrogen (DH) on crack growth rate (CGR) are discussed. Results show that the CGR of alloy 600 in hydrogenated water (at the Ni/NiO phase boundary) is about 2-200 times higher than in 2 ppm O2 oxygenated water at 325°C and 360°C, while the opposite behavior was observed at 288°C. Much more severe intergranular oxidation was observed[...]"

 

Source: Science Direct
Authors: Jiamei Wang et al.
DOI: https://doi.org/10.1016/j.jnucmat.2020.152603

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Impact of the Agulhas Return Current on the oceanography of the Kerguelen Plateau region, Southern Ocean, over the last 40 kyrs

Abstract.

"The oceanography of the western Indian sector of the Southern Ocean is extremely complex due to the presence of several subantartic islands and plateaus that alter the zonal flow of the Antarctic Circumpolar Current. The circulation is even more complex around the Kerguelen Islands (KI) as the hydrological fronts merge with the Agulhas Return Current, the latter transporting warm surface waters from the low latitudes to the Subantarctic Zone (SAZ) east of KI. Here we present new sea-surface and sub-surface temperatures, based on diatom and radiolarian census[...]"

 

Source: Science Direct
Authors: M.Civel-Mazens et al.
DOI:https://doi.org/10.1016/j.quascirev.2020.106711

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Variable coastal hypoxia exposure and drivers across the southern California Current

Abstract.

"Declining oxygen is one of the most drastic changes in the ocean, and this trend is expected to worsen under future climate change scenarios. Spatial variability in dissolved oxygen dynamics and hypoxia exposures can drive differences in vulnerabilities of coastal ecosystems and resources, but documentation of variability at regional scales is rare in open-coast systems. Using a regional collaborative network of dissolved oxygen and temperature sensors maintained by scientists and fishing cooperatives from California, USA, and Baja California, Mexico, we characterize spatial and temporal variability in dissolved oxygen[...]"

 

Source: Nature Scientific Reports
Authors: Natalie H. N. Low et al.
DOI: https://doi.org/10.1038/s41598-021-89928-4

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Increase of a hypoxia-tolerant fish, Harpadon nehereus (Synodontidae), as a result of ocean deoxygenation off southwestern China

Abstract.

"We report a sudden explosive rise in abundance off southeastern China of a fish species that is hypoxia-tolerant, Bombay duck (Harpadon nehereus, Family Synodontidae), belonging to an Order (the Aulopiformes) encompassing overwhelmingly deep-sea fishes, but which predominantly occurs in coastal water. We suggest that this is made possible by the very high water content of its muscle and other tissues (about 90%, vs 75–80% for other coastal fish), which reduces its oxygen requirements and allows it to outcompete other fish in low-oxygen[...]"

 

Source: Environmental Biology of Fishes
Authors: Bin Kang et al.
DOI: https://doi.org/10.1007/s10641-021-01130-7

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Hydrostatic pressure is the universal key driver of microbial evolution in the deep ocean and beyond

Abstract.

"Oceans cover approximately 70% of the Earth’s surface, and microbes comprise 90% of the ocean biomass and are regarded as an important ‘hidden’ driver of essential elemental cycling, such as carbon cycling, in the oceans (Karl, 2007; Salazar and Sunagawa, 2017). Although the general public – even many scientists – think of the oceans as unified, stable water systems, they contain varied environments, including extreme environments such as oxygen-deficient zones, oligotrophic open ocean, polar water regions, deep ocean[...]"

 

Source: Environmental Microbiology Reports
Authors: Xiang Xiao et al.
DOI: 10.1111/1758-2229.12915 

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Toward a better understanding of fish-based contribution to ocean carbon flux

Abstract.

"Fishes are the dominant vertebrates in the ocean, yet we know little of their contribution to carbon export flux at regional to global scales. We synthesize the existing information on fish-based carbon flux in coastal and pelagic waters, identify gaps and challenges in measuring this flux and approaches to address them, and recommend research priorities. Based on our synthesis of passive (fecal pellet sinking) and active.[...]".

 

Source: ASLO- Association for the Sciences of Limnology and Oceanography
Authors: Grace K. Saba et al.
DOI: https://doi.org/10.1002/lno.11709

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Extreme Levels of Ocean Acidification Restructure the Plankton Community and Biogeochemistry of a Temperate Coastal Ecosystem: A Mesocosm Study

Abstract.

"The oceans’ uptake of anthropogenic carbon dioxide (CO2) decreases seawater pH and alters the inorganic carbon speciation – summarized in the term ocean acidification (OA). Already today, coastal regions experience episodic pH events during which surface layer pH drops below values projected for the surface ocean at the end of the century. Future OA is expected to further enhance the intensity of these coastal extreme pH events. To evaluate the influence of such episodic OA events in coastal regions, we deployed eight pelagic mesocosms[...]".

 

Source: Frontiers
Authors: Carsten Spisla et al.
DOI: https://doi.org/10.3389/fmars.2020.611157

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Floating macrolitter leaked from Europe into the ocean

Abstract.

"Riverine systems act as converging pathways for discarded litter within drainage basins, becoming key elements in gauging the transfer of mismanaged waste into the ocean. However, riverine litter data are scarce and biased towards microplastics, generally lacking information about larger items. Based on the first ever database of riverine floating macrolitter across Europe, we have estimated that between 307 and 925 million litter items are released annually from Europe into the ocean[...]"

 

Source: Nature
Authors: Daniel González-Fernández et al.
DOI: https://doi.org/10.1038/s41893-021-00722-6

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Evolution of (Bio-)Geochemical Processes and Diagenetic Alteration of Sediments Along the Tectonic Migration of Ocean Floor in the Shikoku Basin off J

Abstract.

"Biogeochemical processes in subseafloor sediments are closely coupled to global element cycles. To improve the understanding of changes in biogeochemical conditions on geological timescales, we investigate sediment cores from a 1,180 m deep hole in the Nankai Trough offshore Japan (Site C0023) drilled during International Ocean Discovery Program Expedition 370. During its tectonic migration from the Shikoku Basin to the Nankai Trough over the past 15 Ma, Site C0023 has experienced significant changes in[...]"

 

Source: AGU- Advancing Earth and Space Science
Authors: Male Köster et al.
DOI: https://doi.org/10.1029/2020GC009585

Read the full article here.


Deoxygenation in Marginal Seas of the Indian Ocean

Abstract.

"This article describes oxygen distributions and recent deoxygenation trends in three marginal seas – Persian Gulf and Red Sea in the Northwestern Indian Ocean (NWIO) and Andaman Sea in the Northeastern Indian Ocean (NEIO). Vertically mixed water column in the shallow Persian Gulf is generally well-oxygenated, especially in winter. Biogeochemistry and ecosystems of Persian Gulf are being subjected to enormous anthropogenic stresses including large loading of nutrients and organic matter, enhancing oxygen demand and causing hypoxia (oxygen < 1.4 ml l–1) in central and southern Gulf in summer. The larger and deeper Red Sea is relatively less affected by human[...]"

 

Source: Frontiers
Authors: S. Wajih A. Naqvi
DOI: https://doi.org/10.3389/fmars.2021.624322


Temperature and dissolved oxygen concentration in the Pacific Ocean at the northern region of the oxygen minimum zone off Mexico between the last two

Abstract.

"The changes in temperature and dissolved oxygen concentration in the Pacific Ocean in the northern region of the shallow oxygen minimum zone (OMZ) off Mexico were analyzed on the basis of the Word Ocean Database and a series of oceanographic cruises (LEGOZ-Mex). In order to test the changes in both parameters between two similar oceanographic scenarios according to the Pacific Decadal Oscillation (PDO), a comparison was made between the last two cool PDO phases of 1962–1974 and 2002–2012 when conditions[...]"

 

Source: Science Direct
Authors: E.D.Sánchez-Pérez et al.
DOI: https://doi.org/10.1016/j.jmarsys.2021.103607

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Antarctic icebergs reorganize ocean circulation during Pleistocene glacials

Abstract.

"The dominant feature of large-scale mass transfer in the modern ocean is the Atlantic meridional overturning circulation (AMOC). The geometry and vigour of this circulation influences global climate on various timescales. Palaeoceanographic evidence suggests that during glacial periods of the past 1.5 million years the AMOC had markedly different features from today1; in the Atlantic basin, deep waters of Southern Ocean origin[...]"

 

Source: Nature
Authors: Aidan Starr et al.
DOI: https://doi.org/10.1038/s41586-020-03094-7

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Ocean acidification locks algal communities in a species-poor early successional stage

Abracts.

"Long-term exposure to CO2-enriched waters can considerably alter marine biological community development, often resulting in simplified systems dominated by turf algae that possess reduced biodiversity and low ecological complexity. Current understanding of the underlying processes by which ocean acidification alters biological community development and stability remains limited, making the management of such shifts problematic. Here, we deployed recruitment tiles in reference[...]"

 

Source: Wiley Online Library
Authors: Ben P. Harvey et al.
DOI: https://doi.org/10.1111/gcb.15455

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Zooplankton grazing of microplastic can accelerate global loss of ocean oxygen

Abstract.

"Global warming has driven a loss of dissolved oxygen in the ocean in recent decades. We demonstrate the potential for an additional anthropogenic driver of deoxygenation, in which zooplankton consumption of microplastic reduces the grazing on primary producers. In regions where primary production is not limited by macronutrient availability, the reduction of grazing pressure on primary producers causes export production to increase. Consequently, organic particle remineralisation in these regions[...]"

 

Source: Nature Communications
Authors: K. Kvale et al.
DOI: https://doi.org/10.1038/s41467-021-22554-w

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Oxygen Seasonality, Utilization Rate, and Impacts of Vertical Mixing in the Eighteen Degree Water Region of the Sargasso Sea as Observed by Profiling

Abstract.

"Seasonal oxygen structure and utilization in the Sargasso Sea are characterized using nine profiling floats with oxygen 2021 sensors (years 2005–2008), deployed in an Eighteen Degree Water (EDW) experiment (CLIMODE). During autumn-winter when the mixed layer is deepening, oxygen increases from the surface to the base of the EDW at 400 m. During spring-summer, oxygen decreases except between the seasonal pycnocline and compensation depth, creating the seasonal shallow oxygen maximum layer (SOMax) with oxygen production[...]"

 

Source: Advancing Earth and Space Science
Authors: Samuel J. Billheimer et al.
DOI: https://doi.org/10.1029/2020GB006824

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Fossil evidence for vampire squid inhabiting oxygen-depleted ocean zones since at least the Oligocene

Abstract.

"A marked 120 My gap in the fossil record of vampire squids separates the only extant species (Vampyroteuthis infernalis) from its Early Cretaceous, morphologically-similar ancestors. While the extant species possesses unique physiological adaptations to bathyal environments with low oxygen concentrations, Mesozoic vampyromorphs inhabited epicontinental shelves. However, the timing of their retreat towards bathyal and oxygen-depleted habitats is poorly documented. Here, we document a first record of a post-Mesozoic vampire squid from the Oligocene of the Central Paratethys represented[...]"

 

Source: Communications Biology
Authors: Martin Košťák et al.
DOI: https://doi.org/10.1038/s42003-021-01714-0

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The Ocean barcode atlas: A web service to explore the biodiversity and biogeography of marine organisms

Abstract.

"The Ocean Barcode Atlas (OBA) is a user friendly web service designed for biologists who wish to explore the biodiversity and biogeography of marine organisms locked in otherwise difficult to mine planetary scale DNA metabarcode data sets. Using just a web browser, a comprehensive picture of the diversity of a taxon or a barcode sequence is visualized graphically on world maps and interactive charts. Interactive results panels allow dynamic threshold adjustments and the display of diversity results[...]"

 

Source: Wiley Online Library
Authors: Caroline Vernette et al.
DOI: https://doi.org/10.1111/1755-0998.13322

Read the full article here.


Antioxidant responses of the mussel Mytilus coruscus co-exposed to ocean acidification, hypoxia and warming

Abstract.

"In the present study, the combined effects of pH, dissolved oxygen (DO) and temperature levels on the antioxidant responses of the mussel Mytilus coruscus were evaluated. Mussels were exposed to two pH (8.1, 7.7-acidification), two DO (6 mg L−1, 2 mg L−1-hypoxia) and two temperature levels[...]"

 

Source: Science Direct
Authors: Fahim Ullah Khan et al
DOI: https://doi.org/10.1016/j.marpolbul.2020.111869

Read the full article here.


Redox control on the tungsten isotope composition of seawater

Abstract.

"Free oxygen represents an essential basis for the evolution of complex life forms on a habitable Earth. The isotope composition of redox-sensitive trace elements such as tungsten (W) can possibly trace the earliest rise of oceanic oxygen in Earth’s history. However, the impact of redox changes on the W isotope composition of seawater is still unknown. Here, we report highly variable W isotope compositions in the water column of a redox-stratified basin (δ186/184W between +0.347 and +0.810 ‰) that contrast with the homogenous W isotope composition of the open ocean[...]"

 

Source: PNAS- Proceedings of the National Academy of Sciences of the United States of America
Authors: Florian Kurzweil et al.
DOI: https://doi.org/10.1073/pnas.2023544118

Read the full article here.


A benthic oxygen oasis in the early Neoproterozoic ocean

Abstract.

"Benthic oxygen oases linked to photosynthetic mats have been reported in modern anoxic aquatic systems. Benthic macroalgal blooms were common in stratified, anoxic Neoproterozoic oceans, leading us to hypothesize the existence of benthic oxygen oases at that time. This hypothesis has significant implications regarding the bioavailability of transition metals (e.g., Cu, Zn, Ni, Mo, V) and the distribution of aerobic eukaryotes in these oceans[...]"

 

Source: Science Direct
Authors: Haiyang Wang et al.
DOI: https://doi.org/10.1016/j.precamres.2020.106085

Read the full article here.


Ocean acidification locks algal communities in a species-poor early successional stage

Abstract.

"Long-term exposure to CO2-enriched waters can considerably alter marine biological community development, often resulting in simplified systems dominated by turf algae that possess reduced biodiversity and low ecological complexity. Current understanding of the underlying processes by which ocean acidification alters biological community development and stability remains limited, making the management of such shifts problematic. Here, we deployed recruitment[...]"

 

Source: Wiley Online Library
Authors: Ben P. Harvey et al.
DOI: https://doi.org/10.1111/gcb.15455

Read the full article here.


Environmental Drivers of Mesophotic Echinoderm Assemblages of the Southeastern Pacific Ocean

Abstract.

"Mesophotic ecosystems (50–400 m depth) of the southeastern Pacific have rarely been studied because of the logistical challenges in sampling across this remote zone. This study assessed how oxygen concentrations and other environmental predictors explain variation in echinoderm assemblages at these mesophotic systems, where this group is among the predominant fauna. We compiled data on echinoderm taxa at 91 sampling stations, from historical and recent surveys (between 1950 and 2019), covering a longitudinal gradient of approximately 3,700 km along with the Nazca, Salas y Gómez[...]"

 

Source: Frontiers in Marine Science
Authors: Ariadna Mecho et al.
DOI: 10.3389/fmars.2021.574780

Read the full article here.


Coastal eutrophication drives acidification, oxygen loss, and ecosystem change in a major oceanic upwelling system

Abstract.

"Global change is leading to warming, acidification, and oxygen loss in the ocean. In the Southern California Bight, an eastern boundary upwelling system, these stressors are exacerbated by the localized discharge of anthropogenically enhanced nutrients from a coastal population of 23 million people. Here, we use simulations with a high-resolution, physical–biogeochemical model to quantify the link between terrestrial [...]"

 

Source: PNAS- Proceedings of the National Academy of Sciences of the United States of America
Authors: Faycal Kessouri et al.
DOI: https://doi.org/10.1073/pnas.2018856118

Read the full article here.

 


Variability-based constraint on ocean primary production models

Abstract.

"Primary production (PP) is fundamental to ocean biogeochemistry, but challengingly variable. Satellite models are unique tools for investigating PP, but are difficult to compare and validate because of the scale separation between in situ and remote measurements, which also are rarely coincident. Here, I argue that satellite estimates should be log-skew-normally distributed, because of this scale separation and because PP measurements are log-normally distributed.[...]"

 

Source: ASLO- Association for the Sciences of the Limnology and Oceanography 
Authors: B. B. Cael et al.
DOI: https://doi.org/10.1002/lol2.10196

Read the full article here.


Developing achievable alternate futures for key challenges during the UN Decade of Ocean Science for Sustainable Development

Abstract.

"The oceans face a range of complex challenges for which the impacts on society are highly uncertain but mostly negative. Tackling these challenges is testing society’s capacity to mobilise transformative action, engendering a sense of powerlessness. Envisaging positive but realistic visions of the future, and considering how current knowledge, resources, and technology could be used to achieve these futures, may lead to greater[...]"

 

Source: Reviews in Fish Biology and Fisheries
Authors: Kirsty L. Nash et al.
DOI: https://doi.org/10.1007/s11160-021-09635-1

Read the full article here.


Protecting the global ocean for biodiversity, food and climate

Abstract.

"The ocean contains unique biodiversity, provides valuable food resources and is a major sink for anthropogenic carbon. Marine protected areas (MPAs) are an effective tool for restoring ocean biodiversity and ecosystem services1,2, but at present only 2.7% of the ocean is highly protected3. This low level of ocean protection is due largely to conflicts with fisheries and other extractive uses. To address this issue[...]"

 

Source: Nature
Authors: Enric Sala et al.
DOI: https://doi.org/10.1038/s41586-021-03371-z

Read the full article here.


Wind, waves, and surface currents in the Southern Ocean: observations from the Antarctic Circumnavigation Expedition

Abstract.

"The Southern Ocean has a profound impact on the Earth's climate system. Its strong winds, intense currents, and fierce waves are critical components of the air–sea interface and contribute to absorbing, storing, and releasing heat, moisture, gases, and momentum. Owing to its remoteness and harsh environment, this region is significantly undersampled, hampering the validation of prediction models and large-scale observations from satellite sensors. Here, an unprecedented data set of simultaneous observations of wind [...]"

 

Source: Earth System Science Data
Authors: Marzieh H. Derkani et al.
DOI: https://doi.org/10.5194/essd-13-1189-2021

Read the full article here.


Seaweed farms provide refugia from ocean acidification

Abstract.

"Seaweed farming has been proposed as a strategy for adaptation to ocean acidification, but evidence is largely lacking. Changes of pH and carbon system parameters in surface waters of three seaweed farms along a latitudinal range in China were compared, on the weeks preceding harvesting, with those of the surrounding seawaters. Results confirmed that seaweed farming is efficient in buffering acidification, with Saccharina japonica showing the highest capacity of 0.10 pH increase within the aquaculture area[...]"

 

Source: Science Direct
Authors: Xi Xiao et al
DOI: https://doi.org/10.1016/j.scitotenv.2021.145192

Read the full article here.


The effects of historical ozone changes on Southern Ocean heat uptake and storage

Abstract.

"Atmospheric ozone concentrations have dramatically changed in the last five decades of past century. Herein we explore the effects of historical ozone changes that include stratospheric ozone depletion on Southern Ocean heat uptake and storage, by comparing CESM1 large ensemble simulations with fixed-ozone experiment. During 1958–2005, the ozone changes contribute to about 50% of poleward intensification of the Southern Hemisphere westerly winds in historical simulations, which intensifies the Deacon Cell and residual meridional overturning circulation, thus contributing to heat redistribution[...]"

 

Source: Climate Dynamics
Authors: Shouwei Li et al.
DOI: https://doi.org/10.1007/s00382-021-05803-y

Read the full article here.


Biogeochemical evolution and organic carbon deposition on the Northwestern European Shelf during the Toarcian Ocean Anoxic Event

Abstract.

"The Toarcian Oceanic Anoxic Event (T-OAE, ~183 Ma) represents a well-known episode of organic-rich deposition, which is accompanied by a substantial negative carbon-isotope excursion (CIE). Underpinning the relationships between the carbon-cycle perturbation, ocean anoxia, primary productivity feedbacks and the enrichment of sedimentary organic carbon remains a major challenge. Here, we present high-resolution geochemical[...]"

 

Source: Science Direct
Authors: Alexander J.P.Houben et al.
DOI: https://doi.org/10.1016/j.palaeo.2020.110191

Read the full article here.


Reactive Nitrogen Cycling in the Atmosphere and Ocean

Abstract.

"The budget of reactive nitrogen (Nr; oxidized and reduced inorganic and organic forms of nitrogen) has at least doubled since the preindustrial era due to human activities. Excess Nr causes significant detrimental effects on many terrestrial and aquatic ecosystems; less is known about the impact on the open ocean. Nr deposition may already rival biological N2 fixation quantitatively and will likely continue to rise.[...]"

 

Source: Annual Review of Earth and Planetary Sciences
Authors: Katye E. Altieri et al.
DOI: https://doi.org/10.1146/annurev-earth-083120-052147

Read the full article here.


Marine Litter Windrows: A Strategic Target to Understand and Manage the Ocean Plastic Pollution

Abstract.

"Windrow is a long-established term for the aggregations of seafoam, seaweeds, plankton and natural debris that appear on the ocean surface. Here, we define a “litter windrow” as any aggregation of floating litter at the submesoscale domain (<10 km horizontally), regardless of the force inducing the surface convergence, be it wind or other forces such as tides or density-driven currents. The marine litter windrows observed to date usually form stripes[...]"

 

Source: Frontiers
Authors: Andrés Cózar et al.
DOI: https://doi.org/10.3389/fmars.2021.571796

Read the full article here.


Heavy iron in large gem diamonds traces deep subduction of serpentinized ocean floor

Abstract.

"Subducting tectonic plates carry water and other surficial components into Earth’s interior. Previous studies suggest that serpentinized peridotite is a key part of deep recycling, but this geochemical pathway has not been directly traced. Here, we report Fe-Ni–rich metallic inclusions in sublithospheric diamonds from a depth of 360 to 750 km with isotopically heavy iron (δ56Fe = 0.79 to 0.90‰) and unradiogenic osmium[...]"

 

Source: AAAS
Authors: Evan M. Smith et al.
DOI: 10.1126/sciadv.abe9773

Read the full article here.


Dissolved Organic Matter in the Upwelling System off Peru: Imprints of Bacterial Activity and Water Mass Characteristics

Abstract.

"Microbial degradation of dissolved organic matter (DOM) contributes to the formation and preservation of oxygen minimum zones (OMZs) in the ocean, but information on the spatial distribution and molecular composition of DOM in OMZ regions is scarce. We quantified molecular components of DOM that is, dissolved amino acids (DAA) and dissolved combined carbohydrates (DCCHO), in the upwelling region off Peru. We found the highest concentrations of DCCHO in fully oxygenated[...]"

 

Source: Advancing Earth and Space Science
Authors: Anja Engel et al.
DOI: https://doi.org/10.1029/2020JG006048

Read the full article here.


Ocean currents as a potential dispersal pathway for Antarctica’s most persistent non-native terrestrial insect

Abstract.

"The non-native midge Eretmoptera murphyi is Antarctica’s most persistent non-native insect and is known to impact the terrestrial ecosystems. It inhabits by considerably increasing litter turnover and availability of soil nutrients. The midge was introduced to Signy Island, South Orkney Islands, from its native South Georgia, and routes of dispersal to date have been aided by human activities, with little known about non-human-assisted methods of dispersal. This study is the first to determine the potential for dispersal [...]"

 

Source: Polar Biology
Authors: Jesamine C. Bartlett et al.
DOI:https://doi.org/10.1007/s00300-020-02792-2

Read the full article here.


Deoxygenation impacts on Baltic Sea cod: Dramatic declines in ecosystem services of an iconic keystone predator

Abstract.

"The intensified expansion of the Baltic Sea’s hypoxic zone has been proposed as one reason for the current poor status of cod (Gadus morhua) in the Baltic Sea, with repercussions throughout the food web and on ecosystem services. We examined the links between increased hypoxic areas and the decline in maximum length of Baltic cod, a demographic proxy for services[...]"

 

Source: Ambio
Authors: Alessandro Orio et al.
DOI: https://doi.org/10.1007/s13280-021-01572-4

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Ocean acidification may slow the pace of tropicalization of temperate fish communities

Abstract.

"Poleward range extensions by warm-adapted sea urchins are switching temperate marine ecosystems from kelp-dominated to barren-dominated systems that favour the establishment of range-extending tropical fishes. Yet, such tropicalization may be buffered by ocean acidification, which reduces urchin grazing performance and the urchin barrens that tropical range-extending fishes prefer.[...]"

 

Source: Nature Climate Change
Authors: Ericka O. C. Coni et al.
DOI: https://doi.org/10.1038/s41558-020-00980-w

Read the full article here.


Global declines in coral reef calcium carbonate production under ocean acidification and warming

Abstract.

"Ocean warming and acidification threaten the future growth of coral reefs. This is because the calcifying coral reef taxa that construct the calcium carbonate frameworks and cement the reef together are highly sensitive to ocean warming and acidification. However, the global-scale effects of ocean warming and acidification on rates of coral reef net carbonate production remain poorly constrained despite a wealth of studies assessing their effects on the calcification of individual organisms[...]"

 

Source: PNAS- Proceedings of the National Academy of Sciences of the United States of America
Authors: Christopher E. Cornwall et al.
DOI: https://doi.org/10.1073/pnas.2015265118

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The poleward enhanced Arctic Ocean cooling machine in a warming climate

Abstract.

"As a cooling machine of the Arctic Ocean, the Barents Sea releases most of the incoming ocean heat originating from the North Atlantic. The related air-sea heat exchange plays a crucial role in both regulating the climate and determining the deep circulation in the Arctic Ocean and beyond. It was reported that the cooling efficiency of this cooling machine has decreased significantly. In this study, we find that the overall cooling efficiency did not really drop: When the cooling efficiency decreased in the southern Barents Sea[...]"

 

Source: Nature Communications
Authors: Qi Shu et al.
DOI: https://doi.org/10.1038/s41467-021-23321-7

Read the full article here.


Rain-fed streams dilute inorganic nutrients but subsidise organic-matter-associated nutrients in coastal waters of the northeast Pacific Ocean

Abstract.

"In coastal regions, rivers and streams may be important sources of nutrients limiting to primary production in marine waters; however, sampling is still rarely conducted across the land-to-ocean aquatic continuum, precluding conclusions from being drawn about connectivity between freshwater and marine systems. Here we use a more-than-4-year dataset (2014–2018) of nutrients (nitrogen, phosphorus, silica, iron) and dissolved organic carbon spanning streams draining coastal watersheds and nearshore marine surface waters along the Central Coast of British Columbia, Canada, at the heart of the North Pacific coastal temperate[...]"

 

Source: Biogeosciences
Authors: Kyra A. St. Pierre et al.
DOI: https://doi.org/10.5194/bg-18-3029-2021

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Observed Seasonal and Interannual Controls on Coastal Oxygen and Dead Zones in the Indian Ocean

Abstract.

"A major concern is that global de-oxygenation will expand Oxygen minimum zones (OMZs) and favor coastal dead zones (DZs) where already low oxygen levels threaten ecosystems and adjacent coastal economies. The northern Indian ocean is home to both intense OMZs and DZs, and is surrounded by many kilometers of biodiverse and commercially valuable coastline. Exchanges between OMZs and shelf waters that contribute to coastal DZs are subject to the strong monsoonal seasonal cycle[...]"

 

Source: EGU General Assambly
Authors: Jenna Pearson et al.
DOI: https://doi.org/10.5194/egusphere-egu21-1421

Read the full article here.


Can seafloor voltage cables be used to study large-scale circulation? An investigation in the Pacific Ocean

Abstract.

"Marine electromagnetic (EM) signals largely depend on three factors: flow velocity, Earth's main magnetic field, and seawater's electrical conductivity (which depends on the local temperature and salinity). Because of this, there has been recent interest in using marine EM signals to monitor and study ocean circulation. Our study utilizes voltage data from retired seafloor telecommunication cables in the Pacific Ocean to examine whether such cables could be used to monitor circulation velocity or transport on large oceanic scales. We process the cable data to isolate the seasonal and monthly variations and then evaluate the correlation between the processed data and numerical predictions of the electric field[...]"

 

Source: EGU-European Geosciences Union
Authors: Jakub Velímský et al.
DOI: https://doi.org/10.5194/os-17-383-2021

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Intrinsic oceanic decadal variability of upper-ocean heat content

Abstract.

"Atmosphere and ocean are coupled via air–sea interactions. The atmospheric conditions fuel the ocean circulation and its variability, but the extent to which ocean processes can affect the atmosphere at decadal time scales remains unclear. In particular, such low-frequency variability is difficult to extract from the short observational record, meaning that climate models are the primary tools deployed to resolve this question. Here, we assess how the ocean’s intrinsic variability leads to patterns of upper-ocean heat content [...]"

 

Source: AMS- American Meteorological Society
Authors: Navid C. Constantinou et al.
DOI: https://doi.org/10.1175/JCLI-D-20-0962.1

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Effect of Resolving Ocean Eddies on the Transient Response of Global Mean Surface Temperature to Abrupt 4xCO2 Forcing

Abstract.

"The magnitude of global mean surface temperature (GMST) response to increasing atmospheric CO2 concentrations is affected by the efficiency of ocean heat uptake, which in turn can be affected by oceanic mesoscale eddies. Using the Max Planck Institute ‐ Earth System Model (MPI‐ESM1.2), we find that resolving eddies[...]"

 

Source: Advancing Earth and Space Science
Authors: D. A. Putrasahan et al.
DOI: https://doi.org/10.1029/2020GL092049


A global viral oceanography database (gVOD)

Abstract.

"Virioplankton are a key component of the marine biosphere in maintaining diversity of microorganisms and stabilizing ecosystems. They also contribute greatly to nutrient cycles/cycling by releasing organic matter after lysis of hosts. In this study, we constructed the first global viral oceanography database (gVOD) by collecting 10 931 viral abundance (VA) data and 727 viral production (VP) data, along with host and relevant oceanographic parameters when available. Most VA data were obtained in the North Atlantic (32 %) and North Pacific (29 %) oceans, while the southeast Pacific[...]"

 

Source: Earth System Science Data 
Authors: Le Xie et al.
DOI: https://doi.org/10.5194/essd-13-1251-2021

Read the full article here.


Photosensitized formation of sulfate and volatile sulfur gases from dissolved organic sulfur: Roles of pH, dissolved oxygen, and salinity

Abstract.

"The photodegradation of dissolved organic sulfur (DOS) is a potential source of aqueous sulfate and its chemical precursors in surface water. However, the photochemical fate of DOS and factors that control its fate still remain unclear. Herein, we employed a DOS model featuring a photosensitizer (humic acids, HA) to investigate the photochemical degradation pathways of DOS in various natural water sources, from which we observed the substantial photosensitized formation of sulfate, methanesulfonic acid (MSA), carbonyl [...]"

 

Source: Science Direct
Authors: Jian-Long Li et al.
DOI: https://doi.org/10.1016/j.scitotenv.2021.147449

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How deep ocean-land coupling controls the generation of secondary microseism Love waves

Abstract.

"Wind driven ocean wave-wave interactions produce continuous Earth vibrations at the seafloor called secondary microseisms. While the origin of associated Rayleigh waves is well understood, there is currently no quantified explanation for the existence of Love waves in the most energetic region of the microseism spectrum (3–10 s). Here, using terrestrial seismic arrays and 3D synthetic acoustic-elastic simulations combined with ocean wave hindcast data, we demonstrate that, observed from land[...]"

 

Source: Nature Communications
Authors: Florian Le Pape et al.
DOI: https://doi.org/10.1038/s41467-021-22591-5

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Investigating the Roles of External Forcing and Ocean Circulation on the Atlantic Multidecadal SST Variability in a Large Ensemble Climate Model Hiera

Abstract.

"This paper attempts to enhance our understanding of the causes of Atlantic Multidecadal Variability, the AMV. Following the literature, we define the AMV as the SST averaged over the North Atlantic basin, linearly detrended and low-pass filtered. There is an ongoing debate about the drivers of the AMV, which include internal variability generated from the ocean or atmosphere (or both), and external radiative forcing. We test the role of these factors in explaining the time history, variance, and spatial pattern of the AMV using[...]"

 

Source: American Meteorological Soceity 
Authors: Lisa N. Murphy et al.
DOI: https://doi.org/10.1175/JCLI-D-20-0167.1

Read the full article here.

 

 


Warum Sauerstoff im Meer fehlt

Video recommendation.

"Im Meer gibt es immer mehr Stellen, in denen es kaum noch Sauerstoff gibt: sogenannte "Todeszonen". Wir erklären euch, warum das ein Problem ist."

Source: ZDF
 

watch the video here.


Zooplankton grazing of microplastic can accelerate global loss of ocean oxygen

Abstract.

"Global warming has driven a loss of dissolved oxygen in the ocean in recent decades. We demonstrate the potential for an additional anthropogenic driver of deoxygenation, in which zooplankton consumption of microplastic reduces the grazing on primary producers. In regions where primary production is not limited by macronutrient availability, the reduction of grazing pressure on primary producers causes export production to increase. Consequently, organic particle remineralisation in[...]"

 

Source: Nature Communications 
Authors: K. Kvale et al.
DOI: https://doi.org/10.1038/s41467-021-22554-w

Read the full article here.


A committed fourfold increase in ocean oxygen loss

Abstract.

"Less than a quarter of ocean deoxygenation that will ultimately be caused by historical CO2 emissions is already realized, according to millennial-scale model simulations that assume zero CO2 emissions from year 2021 onwards. About 80% of the committed oxygen loss occurs below 2000 m depth, where a more sluggish overturning circulation will increase water residence times and accumulation of respiratory oxygen demand. According to the model results, the deep ocean will thereby lose more than 10% of its pre-industrial oxygen content even if CO2 emissions and thus global warming[...]"

 

Source: Nature Communications
Authors: Andreas Oschlies 
DOI: https://doi.org/10.1038/s41467-021-22584-4

Read the full article here.


Small phytoplankton contribute greatly to CO2-fixation after the diatom bloom in the Southern Ocean

Abstract.

"Phytoplankton is composed of a broad-sized spectrum of phylogenetically diverse microorganisms. Assessing CO2-fixation intra- and inter-group variability is crucial in understanding how the carbon pump functions, as each group of phytoplankton may be characterized by diverse efficiencies in carbon fixation and export to the deep ocean. We measured the CO2-fixation of different groups of phytoplankton at the single-cell level around the naturally iron-fertilized Kerguelen plateau (Southern Ocean)[...]"

 

Source: The ISME Journal 
Authors: Solène Irion et al
DOI: https://doi.org/10.1038/s41396-021-00915-z

Read the full article here.


A pole-to-equator ocean ousverturning circulation on Encelad

Abstract.

"Enceladus is believed to have a saltwater global ocean, heated at the ocean–core interface and losing heat to the floating ice shell above. This configuration suggests an important role for vertical convection. The ice shell has dramatic meridional thickness variations that, in steady state, must be sustained by the ocean circulation against processes acting to remove these anomalies. This could be achieved through spatially separated regions of freezing and melting at the ocean–ice interface. Here, we use an idealized[...]"

 

Source: Nature Geoscience
Authours: Ana H. Lobo et al.
DOI: https://doi.org/10.1038/s41561-021-00706-3

Read the full article here.


Current Atlantic Meridional Overturning Circulation weakest in last millennium

Abstract.

"The Atlantic Meridional Overturning Circulation (AMOC)—one of Earth’s major ocean circulation systems—redistributes heat on our planet and has a major impact on climate. Here, we compare a variety of published proxy records to reconstruct the evolution of the AMOC since about AD 400. A fairly consistent picture of the AMOC emerges: after a long and relatively stable period, there was an initial weakening starting in the nineteenth century, followed by a second, more rapid, decline in the mid-twentieth[...]"

 

Source: Nature Geosciences
Authors: L. Caesar et al.
DOI: https://doi.org/10.1038/s41561-021-00699-z

Read the full article here.


Pervasive distribution of polyester fibres in the Arctic Ocean is driven by Atlantic inputs

Abstract.

"Microplastics are increasingly recognized as ubiquitous global contaminants, but questions linger regarding their source, transport and fate. We document the widespread distribution of microplastics in near-surface seawater from 71 stations across the European and North American Arctic - including the North Pole. We also characterize samples to a depth of 1,015 m in the Beaufort Sea. Particle abundance correlated with longitude, with almost three times more particles in the eastern Arctic compared to the west. Polyester comprised[...]"

 

Source: Nature Communications
Authors: Peter S. Ross et al.
DOI: https://doi.org/10.1038/s41467-020-20347-1

Read the full article here.


Gulf of Mexico blue hole harbors high levels of novel microbial lineages

Abstract.

"Exploration of oxygen-depleted marine environments has consistently revealed novel microbial taxa and metabolic capabilities that expand our understanding of microbial evolution and ecology. Marine blue holes are shallow karst formations characterized by low oxygen and high organic matter content. They are logistically challenging to sample, and thus our understanding of their biogeochemistry and microbial ecology is limited. We present a metagenomic and geochemical characterization of Amberjack Hole on the Florida continental shelf (Gulf of Mexico). Dissolved oxygen became depleted at the hole’s rim[...]"

 

Source: The ISME Journal 
Authors: N. V. Patin et al.
DOI: https://doi.org/10.1038/s41396-021-00917-x

Read the full article here.


Iron isotopes trace primordial magma ocean cumulates melting in Earth’s upper mantle

Abstract.

"The differentiation of Earth ~4.5 billion years (Ga) ago is believed to have culminated in magma ocean crystallization, crystal-liquid separation, and the formation of mineralogically distinct mantle reservoirs. However, the magma ocean model remains difficult to validate because of the scarcity of geochemical tracers of lower mantle mineralogy. The Fe isotope compositions (δ57Fe) of ancient mafic rocks can be used to reconstruct the mineralogy of their mantle source regions. We present Fe isotope data for 3.7-Ga metabasalts from the Isua Supracrustal Belt (Greenland). The δ57Fe signatures[...]"

 

Source: Science Advances
Authors: Helen M. Williams et al.
DOI:10.1126/sciadv.abc7394

Read the full article here.


An integrated framework for lean manufacturing in relation with blue ocean manufacturing - A case study

Abstract.

"Lean Manufacturing (LM) has traditionally helped industries in removing the non-value-added processes to achieve operational excellence. Similarly, the blue ocean strategy helps organizations in creating an uncontested market space where the competition is irrelevant. The authors posit that the integration of two approaches helps in achieving holistic manufacturing excellence, and there is a paucity of approaches that integrate the two paradigms. In order to fill this research gap, the authors have developed an integrated framework that combines the concepts of lean[...]"

 

Source: Science Direct
Authors: Saba Sadiq et al.
DOI: https://doi.org/10.1016/j.jclepro.2020.123790

Read the full article here.


Stable isotopic composition of top consumers in Arctic cryoconite holes: revealing divergent roles in a supraglacial trophic network

Abstract.

"Arctic cryoconite holes represent highly biologically active aquatic habitats on the glacier surface characterized by the dynamic nature of their formation and functioning. The most common cryoconite apex consumers are the cosmopolitan invertebrates – tardigrades and rotifers. Several studies have highlighted the potential relevance of tardigrades and rotifers to cryoconite holes' ecosystem functioning. However, due to the dominant occurrence of prokaryotes, these consumers are usually out of the major scope of most studies aimed at understanding biological processes on glaciers. The aim of this descriptive study is to present pioneering[...]"

 

Source: Biogeosciences
Authors: Tereza Novotná Jaroměřská et al.
DOI: https://doi.org/10.5194/bg-18-1543-2021

Read the full article here.


Protecting the global ocean biodiversity, food and climate

Abstract.

"The ocean contains unique biodiversity, provides valuable food resources and is a major sink for anthropogenic carbon. Marine protected areas (MPAs) are an effective tool for restoring ocean biodiversity and ecosystem services1,2, but at present only 2.7% of the ocean is highly protected3. This low level of ocean protection is due largely to conflicts with fisheries and other extractive uses. To address this issue, here we developed a conservation planning framework to prioritize highly protected MPAs in places that would result in multiple benefits today and in the future. We find that a substantial increase in ocean protection could have triple benefits, by protecting biodiversity[...]"

 

Source: Nature
Authors: Enric Sala et al.
DOI: https://doi.org/10.1038/s41586-021-03371-z

Read the full article here.


Climate field completion via Markov random fields – Application to the HadCRUT4.6 temperature dataset

Abstract.

"Surface temperature is a vital metric of Earth’s climate state, but is incompletely observed in both space and time: over half of monthly values are missing from the widely used HadCRUT4.6 global surface temperature dataset. Here we apply GraphEM, a recently developed imputation method, to construct a spatially complete estimate of HadCRUT4.6 temperatures. GraphEM leverages Gaussian Markov random fields (aka Gaussian graphical models) to better estimate covariance relationships within a climate field, detecting anisotropic features such as land/ocean contrasts, orography, ocean currents and wave-propagation pathways.[...]"

 

Source: AMS- American Meteorological Society
Authors: Adam Vaccaro et al.
DOI: https://doi.org/10.1175/JCLI-D-19-0814.1

Read the full article here.


Role of tide-induced vertical mixing in the deep Pacific Ocean circulation

Abstract.

"We investigate the control mechanisms of the deep Pacific Ocean circulation by introducing updated methods for parameterizing tidal mixing. The column-integrated rates of dissipation in near- and far-fields are derived from the tidal energy conversion and dissipation rates estimated by a high resolution tide model. In the calculation of the far-field mixing, its dependency on stratification is taken into account based on theoretical and observational knowledge.Unlike previous studies that did not take the stratification dependence into account, the far-field mixing does not function to significantly enhance the deep Pacific Ocean circulation. The deep Pacific Ocean circulation is also found to be insensitive to the decay scale height of the near-field mixing. However, these factors affect the reproducibility of the[...]"

 

Source: Journal of Oceanography
Authors: Takao Kawasaki et al.
DOI: https://doi.org/10.1007/s10872-020-00584-0

Read the full article here.


Atlantic Ocean science diplomacy in action: the pole-to-pole All Atlantic Ocean Research Alliance

Abstract.

"The ocean provides important ecosystem services to society, but its health is in crisis due to the impacts of human activities. Ocean sustainability requires ambitious levels of scientific evidence to support governance and management of human activities that impact the ocean. However, due to the size, complexity and connectivity of the ocean, monitoring and data collection presupposes high investments, and nations need to cooperate to deliver the ambitious, costly science that is required to inform decisions[...]"

 

Source: Nature - Humanities and Social Sciences Communications
Authors: Andrei Polejack et al.
DOI: https://doi.org/10.1057/s41599-021-00729-6

Read the full article here.


Emerging Solutions to Return Nature to the Urban Ocean

Abstract.

"Urban and periurban ocean developments impact 1.5% of the global exclusive economic zones, and the demand for ocean space and resources is increasing. As we strive for a more sustainable future, it is imperative that we better design, manage, and conserve urban ocean spaces for both humans and nature. We identify three key objectives for more sustainable urban oceans: reduction of urban pressures, protection and restoration of ocean ecosystems, and support of critical ecosystem services. We describe an array of emerging evidence-based approaches, including greening grayinfrastructure, restoring habitats, and developing biotechnologies.

 

Source: ANNUAL REVIEWS
Authors: Laura Airoldi et al.
DOI: https://doi.org/10.1146/annurev-marine-032020-020015

Read the full article here.


A benthic oxygen oasis in the early Neoproterozoic ocean

Abstract.

"Benthic oxygen oases linked to photosynthetic mats have been reported in modern anoxic aquatic systems. Benthic macroalgal blooms were common in stratified, anoxic Neoproterozoic oceans, leading us to hypothesize the existence of benthic oxygen oases at that time. This hypothesis has significant implications regarding the bioavailability of transition metals (e.g., Cu, Zn, Ni, Mo, V) and the distribution of aerobic eukaryotes in these oceans. However, little research has been directed toward testing the benthic oxygen[...]"

 

Source: Science Direct
Authors:Haiyang Wang et al.
DOI: https://doi.org/10.1016/j.precamres.2020.106085

Read the full article here.


Calibration of temperature-dependent ocean microbial processes in the cGENIE.muffin (v0.9.13) Earth system model

Abstract.

"Temperature is a master parameter in the marine carbon cycle, exerting a critical control on the rate of biological transformation of a variety of solid and dissolved reactants and substrates. Although in the construction of numerical models of marine carbon cycling, temperature has been long recognised as a key parameter in the production and export of organic matter at the ocean surface, its role in the ocean interior is much less frequently accounted for. There, bacteria (primarily) transform sinking particulate organic matter (POM) into its dissolved constituents and consume dissolved oxygen (and/or other electron acceptors such as sulfate). The nutrients and carbon[...]"

 

Source: EGU- European Geosciences Union 
Authors: Katherine A. Crichton
DOI: https://doi.org/10.5194/gmd-14-125-2021

Read the full article here.


Regional patterns and temporal evolution of ocean iron fertilization and CO2 drawdown during the last glacial termination

Abstract.

"The last time Earth's climate experienced geologically rapid global warming was associated with the last glacial termination, when atmospheric CO2 concentrations rose from 180 ppmv during the Last Glacial Maximum (LGM, 26-19 kaBP) to ∼260 ppmv by the early Holocene (12-8 kaBP). About one quarter of that difference is thought to be due to a stronger biological pump during glacial times, driven by increased aeolian dust deposition and hence greater iron availability in[...]"

 

Source: Science Direct
Authors: Fabrice Lambert et al.
DOI: https://doi.org/10.1016/j.epsl.2020.116675

Read the full article here.


Fossil evidence for vampire squid inhabiting oxygen-depleted ocean zones since at least the Oligocene

Abstract.

"A marked 120 My gap in the fossil record of vampire squids separates the only extant species (Vampyroteuthis infernalis) from its Early Cretaceous, morphologically-similar ancestors. While the extant species possesses unique physiological adaptations to bathyal environments with low oxygen concentrations, Mesozoic vampyromorphs inhabited epicontinental shelves. However, the timing of their retreat towards bathyal and oxygen-depleted habitats is poorly documented. Here, we document a first record of a post-Mesozoic vampire squid from the Oligocene of the Central Paratethys[...]"

Source: Nature - Communications Biology
Authors: Martin Košťák et al.
DOI: https://doi.org/10.1038/s42003-021-01714-0

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Mixing by Oceanic Lee Waves

Abstract.

"Oceanic lee waves are generated in the deep stratified ocean by the flow of ocean currents over sea floor topography, and when they break, they can lead to mixing in the stably stratified ocean interior. While the theory of linear lee waves is well established, the nonlinear mechanisms leading to mixing are still under investigation. Tidally driven lee waves have long been observed in the ocean, along with associated mixing, but observations of lee waves forced by geostrophic eddies are relatively sparse and largely indirect[...]"

 

Source: Annual Reviews
Authors: Sonya Legg
DOI: https://doi.org/10.1146/annurev-fluid-051220-043904

Read the full article here.


Ocean acidification may slow the pace of tropicalization of temperate fish communities

Abstract.

"Poleward range extensions by warm-adapted sea urchins are switching temperate marine ecosystems from kelp-dominated to barren-dominated systems that favour the establishment of range-extending tropical fishes. Yet, such tropicalization may be buffered by ocean acidification, which reduces urchin grazing performance and the urchin barrens that tropical range-extending fishes prefer. Using ecosystems experiencing natural warming and acidification, we show that ocean acidification could buffer warming-facilitated tropicalization by reducing urchin populations (by 87%) and inhibiting the formation of barrens. This buffering effect of CO2[...]"

Source: Nature Climate Change
Authors: Ericka O. C. Coni et al.
DOI: https://doi.org/10.1038/s41558-020-00980-w

Read the full article here.


Vertical distribution of planktic foraminifera through an oxygen minimum zone: how assemblages and test morphology reflect oxygen concentrations

Abstract.

"Oxygen-depleted regions of the global ocean are rapidly expanding, with important implications for global biogeochemical cycles. However, our ability to make projections about the future of oxygen in the ocean is limited by a lack of empirical data with which to test and constrain the behavior of global climatic and oceanographic models. We use depth-stratified plankton tows to demonstrate that some species of planktic foraminifera are adapted to life in the heart of the pelagic oxygen minimum zone (OMZ). In particular, we identify two species, Globorotaloides hexagonus and Hastigerina parapelagica, living within the eastern tropical North Pacific OMZ. The tests of the former are preserved in marine sediments and could be used to trace the extent and intensity of low-oxygen pelagic habitats in the fossil record. Additional morphometric analyses of G. hexagonus show that tests found in the lowest oxygen[...]"

Source: Biogeosciences
Authors: Catherine V. Davis et al.
DOI: https://doi.org/10.5194/bg-18-977-2021

Read the full article here.


Connecting to the oceans: supporting ocean literacy and public engagement

Abstract.

"Improved public understanding of the ocean and the importance of sustainable ocean use, or ocean literacy, is essential for achieving global commitments to sustainable development by 2030 and beyond. However, growing human populations (particularly in mega-cities), urbanisation and socio-economic disparity threaten opportunities for people to engage and connect directly with ocean environments. Thus, a major challenge in engaging the whole of society in achieving ocean sustainability by 2030 is to develop strategies to improve societal connections to the ocean[...]"

Source: Reviews in Fish Biology and Fisheries
Authors: Rachel Kelly et al.
DOI: https://doi.org/10.1007/s11160-020-09625-9

Read the full article here.
 


Microbial niche differentiation explains nitrite oxidation in marine oxygen minimum zones

Abstract.

"Nitrite is a pivotal component of the marine nitrogen cycle. The fate of nitrite determines the loss or retention of fixed nitrogen, an essential nutrient for all organisms. Loss occurs via anaerobic nitrite reduction to gases during denitrification and anammox, while retention occurs via nitrite oxidation to nitrate. Nitrite oxidation is usually represented in biogeochemical models by one kinetic parameter and one oxygen threshold, below which nitrite oxidation is set to zero. Here we find that the responses of nitrite oxidation[...]"

Source: Nature
Authors: Xin Sun et al.
DOI: https://doi.org/10.1038/s41396-020-00852-3

Read the full article here.


Impact of mid-glacial ice sheets on deep ocean circulation and global climate

Abstract.

"This study explores the effect of southward expansion of Northern Hemisphere (American) mid-glacial ice sheets on the global climate and the Atlantic Meridional Overturning Circulation (AMOC) as well as the processes by which the ice sheets modify the AMOC. For this purpose, simulations of Marine Isotope Stage (MIS) 3 (36 ka) and 5a (80 ka) are performed with an atmosphere–ocean general circulation model. In the MIS3 and MIS5a simulations, the global average temperature decreases by 5.0 and 2.2 ∘C, respectively, compared with the preindustrial climate simulation. The AMOC weakens by 3 % in MIS3, whereas it strengthens[...]"

 

Source: EGU-European Geosciences Union 
Authors: Sam Sherriff-Tadano et al.
DOI: https://doi.org/10.5194/cp-17-95-2021

Read the full article here.


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