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

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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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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

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Abstract.

"The source of oxygen to Earth’s atmosphere is organic carbon burial, whilst the main sink is oxidative weathering of fossil carbon. However, this sink is to insensitive to counteract oxygen rising above its current level of about 21%. Biogeochemical models suggest that wildfires provide an additional regulatory feedback mechanism. However, none have considered how the evolution of different plant groups through time have interacted with this feedback. The Cretaceous Period[...]"

 

Source: Nature Geoscience
Authors: Claire M. Belcher et al.
DOI: https://doi.org/10.1038/s41467-020-20772-2

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Absract.

"The biological pump—the transfer of atmospheric carbon dioxide to the ocean interior and marine sediments as organic carbon—plays a critical role in regulating the long-term carbon cycle, atmospheric composition and climate. Despite its centrality in the Earth system, the response of the biological pump to biotic innovation and climatic fluctuations through most stages of Earth’s history has been largely conjectural. Here we use a mechanistic model of the biological carbon pump to revisit the factors controlling[...]"

 

Source: Nature Geoscience
Authors: Mojtaba Fakhraee et al.
DOI: https://doi.org/10.1038/s41561-020-00660-6

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Abstract.

"Meeting internationally agreed-upon climate targets requires carbon dioxide removal (CDR) strategies coupled with an urgent phase-down of fossil fuel emissions. However, the efficacy and wider impacts of CDR are poorly understood. Enhanced rock weathering (ERW) is a land-based CDR strategy requiring large-scale field trials. Here we show that a low 3.44 t ha−1 wollastonite treatment in an 11.8 ha acid-rain-impacted forested watershed in New Hampshire, USA, led to cumulative carbon capture by carbonic acid weathering of 0.025–0.13 t CO2 ha−1 over 15 years. Despite a 0.8–2.4 t CO2 ha−1 logistical carbon penalty from mining, grinding, transportation[...]"

 

Source: Biogeosciences
Authors: Lyla L. Taylor et al.
DOI: https://doi.org/10.5194/bg-18-169-2021

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Abstract.

"The Arctic is warming more rapidly than other regions of the world leading to ecosystem change including shifts in vegetation communities, permafrost degradation and alteration of tundra surface-atmosphere energy and carbon (C) fluxes, among others. However, year-round C and energy flux measurements at high-latitude sites remain rare. This poses a challenge for evaluating the impacts of climate change on Arctic tundra ecosystems and for developing and evaluating process-based models, which may be used to predict regional and global energy and C feedbacks to the climate system. Our study used 14 years of seasonal eddy covariance (EC) measurements of carbon dioxide (CO2), water and energy fluxes and winter soil chamber CO2 flux measurements at a dwarf-shrub tundra site underlain by continuous permafrost in Canada's Southern Arctic ecozone to evaluate the incorporation[...]"

Source: Biogeosciences
Authors: Gesa Meyer et al.
DOI: https://doi.org/10.5194/bg-2020-458

Abstract.

"Plastic pollution and ocean change have mostly been assessed separately, missing potential interactions that either enhance or reduce future impacts on ecosystem processes. Here, we used manipulative experiments with outdoor mesocosms to test hypotheses about the interactive effects of plastic pollution, ocean warming and acidification on macrophyte detrital decomposition. These experiments focused on detritus from kelp, Ecklonia radiata, and eelgrass, Zostera muelleri, and included crossed treatments of (i) no, low and high plastic pollution, (ii) current/future ocean temperatures, and (iii) ambient/future ocean partial pressure of carbon dioxide (pCO2). High levels of plastic pollution significantly reduced[...]"

 

Source: Science Direct
Authors: Sebastian G. Litchfield et al.
DOI: https://doi.org/10.1016/j.marpolbul.2020.111354

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Abstract.

"Ocean chemical and physical conditions are changing. Here we show decadal variability and recent acceleration of surface warming, salinification, deoxygenation, carbon dioxide (CO2) and acidification in the subtropical North Atlantic Ocean (Bermuda Atlantic Time-series Study site; 1980s to present). Surface temperatures and salinity exhibited interdecadal variability, increased by ~0.85 °C (with recent warming of 1.2 °C) and 0.12, respectively, while dissolved oxygen levels decreased by ~8% (~2% per decade).[...]"

 

Source: Nature - Communications Earth and Environment
Authors: Nicholas Robert Bates et al.
DOI: https://doi.org/10.1038/s43247-020-00030-5

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Abstract.

"The concentration of oxygen exerts major controls on life in the ocean, and its distribution in the ocean and atmosphere carries information about biological productivity, transports of mass and heat, ocean deoxygenation and global carbon sinks. Our understanding of processes underlying oxygen distributions, their key features and variability is often lacking. Here we investigate the magnitude, variability and uncertainty of the air–sea flux of oxygen, carbon dioxide and atmospheric potential oxygen over an annual cycle in the Labrador Sea. We demonstrate that two-thirds of the annual oxygen uptake occurs over only 40 days in winter and is associated with a bubble-mediated component[...]"

 

Source: Nature Geoscience
Authors: D. Atamanchuk et al.
DOI: https://doi.org/10.1038/s41561-020-0532-2

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Abstract.

"Rising atmospheric carbon dioxide (CO2) levels, from fossil fuel combustion and deforestation, along with agriculture and land-use practices are causing wholesale increases in seawater CO2 and inorganic carbon levels; reductions in pH; and alterations in acid-base chemistry of estuarine, coastal, and surface open-ocean waters. On the basis of laboratory experiments and field studies of naturally elevated CO2 marine environments, widespread biological impacts of human-driven ocean acidification have been posited, ranging from changes in organism physiology and population dynamics to altered communities and ecosystems. Acidification, in conjunction with other climate change–related environmental stresses, particularly under future climate change[...]"

 

Source: Annual Review of Environment and Resources
Authors: Scott C. Doney et al.
DOI: https://doi.org/10.1146/annurev-environ-012320-083019

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Abstract.

"High-latitude oceans have been identified as particularly vulnerable to ocean acidification if anthropogenic CO2 emissions continue. Marine microbes are an essential part of the marine food web and are a critical link in biogeochemical processes in the ocean, such as the cycling of nutrients and carbon. Despite this, the response of Antarctic marine microbial communities to ocean acidification is poorly understood. We investigated the effect of increasing fCO2 on the growth of heterotrophic nanoflagellates (HNFs), nano- and picophytoplankton, and prokaryotes (heterotrophic Bacteria and Archaea) in a natural coastal Antarctic marine microbial community from Prydz Bay, East Antarctica.[...]"

 

Source: Biogeosciences
Authors: Stacy Deppeler et al.
DOI: 10.5194/bg-17-4153-2020

Read the  full article here.

 

 

Abstract.

"The ongoing uptake of anthropogenic carbon by the ocean leads to ocean acidification, a process that results in a reduction in pH and in the saturation state of biogenic calcium carbonate minerals aragonite (Ω_arag) and calcite (Ω_calc). Because of its naturally low Ω_arag and Ω_calc (refs.), the Arctic Ocean is considered the region most susceptible to future acidification and associated ecosystem impacts. [...]"

Source: Nature
Authors: Jens Terhaar et al.
DOI: 10.1038/s41586-020-2360-3

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Abstract.

"The Zero Emissions Commitment (ZEC) is the change in global mean temperature expected to occur following the cessation of net CO₂ emissions and as such is a critical parameter for calculating the remaining carbon budget. The Zero Emissions Commitment Model Intercomparison Project (ZECMIP) was established to gain a better understanding of the potential magnitude and sign of ZEC, in addition to the processes that underlie this metric. [...]"

Source: Biogeosciences
Authors: Andrew H. MacDougall et al.
DOI: 10.5194/bg-17-2987-2020

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"Study finds Earth's oceans contain just the right amount of iron; adding more may not improve their ability to absorb carbon dioxide

Historically, the oceans have done much of the planet's heavy lifting when it comes to sequestering carbon dioxide from the atmosphere. Microscopic organisms known collectively as phytoplankton, which grow throughout the sunlit surface oceans and absorb carbon dioxide through photosynthesis, are a key player.

To help stem escalating carbon dioxide emissions produced by the burning of fossil fuels, some scientists have proposed seeding the oceans with iron -- an essential ingredient that can stimulate phytoplankton growth. Such "iron fertilization" would cultivate vast new fields of phytoplankton, particularly in areas normally bereft of marine life. [...]"

Source: Sciencedaily

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Abstract.

"Weddell Sea-derived Antarctic Bottom Water (AABW) is one of the most important deep water masses in the Southern Hemisphere occupying large portions of the deep Southern Ocean (SO) today. While substantial changes in SO-overturning circulation were previously suggested, the state of Weddell Sea AABW export during glacial climates remains poorly understood. [...]"

Source: Nature Communications
Authors: Huang Huang et al.
DOI: 10.1038/s41467-020-14302-3

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Abstract.

"The Southern Ocean south of 30° S represents only one-third of the total ocean area, yet absorbs half of the total ocean anthropogenic carbon and over two-thirds of ocean anthropogenic heat. In the past, the Southern Ocean has also been one of the most sparsely measured regions of the global ocean. [...]"

Source: Nature Geoscience
Authors: Ben Bronselaer et al.
DOI: 10.1038/s41561-019-0502-8

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Abstract.

"The early Aptian Oceanic Anoxic Event (OAE) 1a represents a major perturbation of the Earth's climate system and in particular the carbon cycle, as evidenced by widespread preservation of organic matter in marine settings and a characteristic negative carbon isotopic excursion (CIE) at its onset, followed by a broad positive CIE. The contemporaneous emplacement of a large igneous province (LIP) is invoked as a trigger for OAE 1a (and OAEs in general), but this link and the ultimate source of the carbon perturbation at the onset of OAEs is still debated. [...]"

Source: 
Authors: Markus Adloff et al.
DOI: 10.1016/j.epsl.2019.115947

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Abstract.

"We investigate the climate mitigation potential and collateral effects of direct injections of captured CO₂ into the deep ocean as a possible means to close the gap between an intermediate CO₂ emissions scenario and a specific temperature target, such as the 1.5 ^∘C target aimed for by the Paris Agreement. For that purpose, a suite of approaches for controlling the amount of direct CO₂ injections at 3000 m water depth are implemented in an Earth system model of intermediate complexity. [...]"

Source: Earth System Dynamics
Authors: Fabian Reith et al.
DOI: 10.5194/esd-10-711-2019

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Abstract.

"Roughly a third (~30 ppm) of the carbon dioxide (CO₂) that entered the ocean during ice ages is attributed to biological mechanisms. A leading hypothesis for the biological drawdown of CO₂ is iron (Fe) fertilisation of the high latitudes, but modelling efforts attribute at most 10 ppm to this mechanism, leaving ~20 ppm unexplained [...]"

Source: Nature Communications 
Authors: Pearse J. Buchanan et al.
DOI: 10.1038/s41467-019-12549-z

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Abstract.

"Previous studies have suggested that enhanced weathering and benthic phosphorus (P) fluxes, triggered by climate warming, can increase the oceanic P inventory on millennial timescales, promoting ocean productivity and deoxygenation. In this study, we assessed the major uncertainties in projected P inventories and their imprint on ocean deoxygenation using an Earth system model of intermediate complexity for the same business-as-usual carbon dioxide (CO₂) emission scenario until the year 2300 and subsequent linear decline to zero emissions until the year 3000. [...]"

Source: Earth System Dynamics
Authors: Tronje P. Kemena et al.
DOI: 10.5194/esd-10-539-2019

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"The world's oceans soak up about a quarter of the carbon dioxide that humans pump into the air each year -- a powerful brake on the greenhouse effect. In addition to purely physical and chemical processes, a large part of this is taken up by photosynthetic plankton as they incorporate carbon into their bodies. When plankton die, they sink, taking the carbon with them. Some part of this organic rain will end up locked into the deep ocean, insulated from the atmosphere for centuries or more. [...]"

Source: EurekAlert!

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Abstract.

"The deglacial history of CO2 release from the deep North Pacific remains unresolved. This is due to conflicting indications about subarctic Pacific ventilation changes based on various marine proxies, especially for Heinrich Stadial 1 (HS-1) when a rapid atmospheric CO2 rise occurs. Here, we use a complex Earth System Model to investigate the deglacial North Pacific overturning and its control on ocean stratification. [...]"

Source: Nature Communications
Authors: X. Gong et al.
DOI: 10.1038/s41467-019-08606-2

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Abstract.

"Warm periods in Earth's history tend to cool more slowly than cool periods warm. Here we explore initial differences in how the global ocean takes up and gives up heat and carbon in forced rapid warming and cooling climate scenarios. We force an intermediate-complexity earth system model using two atmospheric CO₂ scenarios. A ramp-up (1% per year increase in atmospheric CO₂ for 150 years) starts from an average global CO₂ concentration of 285 ppm to represent warming of an icehouse climate. [...]"

Source: Environmental Research Letters
Authors: Karin F. Kvale et al.
DOI: 10.1088/1748-9326/aaedc3

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Abstract.

"We investigated how future ocean conditions, and specifically the interaction between temperature and CO2, might affect marine aggregate formation and physical properties. Initially, mesocosms filled with coastal seawater were subjected to three different treatments of CO2 concentration and temperature: (1) 750 ppm CO2, 16°C, (2) 750 ppm CO2, 20°C, and (3) 390 ppm CO2, 16°C. Diatom-dominated phytoplankton blooms were induced in the mesocosms by addition of nutrients. [...]"

Source: Frontiers in Marine Science
Authors: Carolina Cisternas-Novoa et al.
DOI: 10.3389/fmars.2018.00500

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Abstract.

"During the Late Cretaceous and early Cenozoic the Earth experienced prolonged climatic cooling most likely caused by decreasing volcanic activity and atmospheric CO2 levels. However, the causes and mechanisms of subsequent major global warming culminating in the late Paleocene to Eocene greenhouse climate remain enigmatic. We present deep and intermediate water Nd-isotope records from the North and South Atlantic to decipher the control of the opening Atlantic Ocean on ocean circulation and its linkages to the evolution of global climate. [...]"

Source: Nature Communications
Authors: S. J. Batenburg et al.
DOI: 10.1038/s41467-018-07457-7

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Abstract.

"Increased storage of carbon in the oceans has been proposed as a mechanism to explain lower concentrations of atmospheric carbon dioxide during ice ages; however, unequivocal signatures of this storage have not been found. In seawater, the dissolved gases oxygen and carbon dioxide are linked via the production and decay of organic material, with reconstructions of low oxygen concentrations in the past indicating an increase in biologically mediated carbon storage. [...]"

Source: Nature
Authors: Babette A. A. Hoogakker et al.
DOI: 10.1038/s41586-018-0589-x

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"Scientists say warming ocean temperatures mean Oregon’s coastal waters now have a low-oxygen season, or hypoxia season, just as the state’s forests have a fire season.

Hypoxia is a condition in which the ocean water close to the sea floor has such low levels of dissolved oxygen that the organisms living down there die.

Some of the first signs came in 2002 when dead crabs were hauled up in crab pots. Since then, scientists and crabbers say things have worsened."

Source: earthfix.info
Author: Kristian Foden-Vencil

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"Scientists have shown that coastal waters and river estuaries can exhibit unique vulnerabilities to acidification than offshore waters. This acidification, detected in waters off the United States West Coast and the Gulf of Mexico, can lead to disorientation and cognitive problems in some marine fish species, such as salmon, sharks, and cod. This work is presented at the Goldschmidt Conference in Boston.

 

Scientists have recently discovered that marine creatures can be adversely affected by hypercapnia, a condition of too much dissolved CO₂ in seawater (CO₂ partial pressure, or pCO₂). When this level rises above 1000 micro atmospheres (1000 μatm), some fish species suffer cognitive problems and disorientation, such as losing their way or even swimming towards predators. Surface ocean CO₂ partial pressures tend to be around 400 μatm, so until now scientists have thought that hypercapnia was a problem which would only become apparent over time in subsurface waters. [...]"

Source: Phys.org

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Abstract.

"The interplay between ocean circulation and biological productivity affects atmospheric CO₂ levels and marine oxygen concentrations. During the warming of the last deglaciation, the North Pacific experienced a peak in productivity and widespread hypoxia, with changes in circulation, iron supply and light limitation all proposed as potential drivers. [...]"

Source: Nature Geoscience
Authors: William R. Gray et al.
DOI: 10.1038/s41561-018-0108-6

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Abstract.

"Atmospheric carbon dioxide (CO₂) data for the last 420 million years (My) show long-term fluctuations related to supercontinent cycles as well as shorter cycles at 26 to 32 My whose origin is unknown. Periodicities of 26 to 30 My occur in diverse geological phenomena including mass extinctions, flood basalt volcanism, ocean anoxic events, deposition of massive evaporites, sequence boundaries, and orogenic events and have previously been linked to an extraterrestrial mechanism. [...]

Source: Science Advances
Authors: R. Dietmar Müller and Adriana Dutkiewicz
DOI: 10.1126/sciadv.aaq0500

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"June 8th is World Oceans Day, a day to raise awareness of the ocean’s importance to the planet. 93 percent of the excess heat absorbed by the climate system goes into our oceans, creating major consequences. While more extreme storms and rising sea levels are some of the impacts of warmer oceans, rising CO2 levels and the resulting warmer oceans are impacting ocean health itself. The most well­known effects are coral bleaching and ocean acidification, but an emerging issue is the decreasing oxygen levels in the warming waters. [...]"

Source: Climate Central

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Abstract.

"Continued warming of the Arctic Ocean in coming decades is projected to trigger the release of teragrams (1 Tg = 10⁶ tons) of methane from thawing subsea permafrost on shallow continental shelves and dissociation of methane hydrate on upper continental slopes. On the shallow shelves (<100 m water depth), methane released from the seafloor may reach the atmosphere and potentially amplify global warming. On the other hand, biological uptake of carbon dioxide (CO₂) has the potential to offset the positive warming potential of emitted methane, a process that has not received detailed consideration for these settings. Continuous sea−air gas flux data collected over a shallow ebullitive methane seep field on the Svalbard margin reveal atmospheric CO₂ uptake rates (−33,300 ± 7,900 μmol m⁻²⋅d⁻¹) twice that of surrounding waters and ∼1,900 times greater than the diffusive sea−air methane efflux (17.3 ± 4.8 μmol m⁻²⋅d⁻¹).  [...]"

Source: Proceedings of the Nathional Academy of Sciences of the United States of America (PNAS)
Authors: John W. Pohlman et al.
DOI: 10.1073/pnas.1618926114

Full article