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Sensitivities to global change drivers may correlate positively or negatively in a foundational marine macroalga

Abstract.

"Ecological impact of global change is generated by multiple synchronous or asynchronous drivers which interact with each other and with intraspecific variability of sensitivities. In three near-natural experiments, we explored response correlations of full-sibling germling families of the seaweed Fucus vesiculosus towards four global change drivers: elevated CO2 (ocean acidification, OA), ocean warming (OW), combined OA and warming (OAW), nutrient enrichment and hypoxic upwelling. [...]"

Source: Scientific Reports
Authors: Balsam Al-Janabi et al.
DOI: 10.1038/s41598-019-51099-8

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Marine nitrogen fixers mediate a low latitude pathway for atmospheric CO2 drawdown

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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Researchers find global ocean methane emissions dominated by shallow coastal waters

"Methane is a potent greenhouse gas that is being added to the atmosphere through both natural processes and human activities, such as energy production and agriculture.

To predict the impacts of human emissions, researchers need a complete picture of the atmosphere's methane cycle. They need to know the size of the inputs—both natural and human—as well as the outputs. They also need to know how long methane resides in the atmosphere. [...]"

Source: Phys.org

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Global ocean methane emissions dominated by shallow coastal waters

Abstract.

"Oceanic emissions represent a highly uncertain term in the natural atmospheric methane (CH4) budget, due to the sparse sampling of dissolved CH4 in the marine environment. Here we overcome this limitation by training machine-learning models to map the surface distribution of methane disequilibrium (∆CH4). Our approach yields a global diffusive CH4 flux of 2–6TgCH4yr−1 from the ocean to the atmosphere, after propagating uncertainties in ∆CH4 and gas transfer velocity.  [...]"

Source: Nature Communications
Authors: Thomas Weber, Nicola A. Wiseman & Annette Kock 
DOI: 10.1038/s41467-019-12541-7

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Deep Atlantic mysteries unveiled in the face of climate change

"ATLAS is one of these projects you can’t do justice to in a single-page article. For over 3.5 years now, a consortium of multinational industries, SMEs, governments and academia have been sailing across the Atlantic to assess its deep-sea ecosystems. In doing so, they’ve already managed to deeply enhance our understanding of the consequences of climate change as well as inform the development of better management policies and practices. [...]"

Source: Cordis

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Atmosphere–ocean oxygen and productivity dynamics during early animal radiations

Abstract.

"The proliferation of large, motile animals 540 to 520 Ma has been linked to both rising and declining O2 levels on Earth. To explore this conundrum, we reconstruct the global extent of seafloor oxygenation at approximately submillion-year resolution based on uranium isotope compositions of 187 marine carbonates samples from China, Siberia, and Morocco, and simulate O2 levels in the atmosphere and surface oceans using a mass balance model constrained by carbon, sulfur, and strontium isotopes in the same sedimentary successions. [...]"

Source: PNAS
Authors: Tais W. Dahl et al.
DOI: 10.1073/pnas.1901178116

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The Dynamics and Impact of Ocean Acidification and Hypoxia:

Insights from Sustained Investigations in the Northern California Current Large Marine Ecosystem

Abstract.

"Coastal upwelling ecosystems around the world are defined by wind-generated currents that bring deep, nutrient-rich waters to the surface ocean where they fuel exceptionally productive food webs. These ecosystems are also now understood to share a common vulnerability to ocean acidification and hypoxia (OAH). In the California Current Large Marine Ecosystem (CCLME), reports of marine life die-offs by fishers and resource managers triggered research that led to an understanding of the risks posed by hypoxia. Similarly, unprecedented losses from shellfish hatcheries led to novel insights into the coastal expression of ocean acidification. [...]"

Source: Oceanography
Authors: Francis Chan et al.
DOI: 10.5670/oceanog.2019.312

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Scenarios of Deoxygenation of the Eastern Tropical North Pacific During the Past Millennium as a Window Into the Future of Oxygen Minimum Zones

Abstract.

"Diverse studies predict global expansion of Oxygen Minimum Zones (OMZs) as a consequence of anthropogenic global warming. While the observed dissolved oxygen concentrations in many coastal regions are slowly decreasing, sediment core paleorecords often show contradictory trends. This is the case for numerous high-resolution reconstructions of oxygenation in the Eastern Tropical North Pacific (ETNP). [...]"

Source: Frontiers in Marine Science
Authors: Konstantin Choumiline et al.
DOI: 10.3389/feart.2019.00237

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The IPCC oceans report is a wake-up call for policymakers

"The importance of the ocean in climate regulation is enormous—yet undervalued. The ocean is estimated to have absorbed 93 percent of the excess heat generated by human activities since the 1970s, acting as a buffer against the global warming we've seen to date. The majority of the global carbon cycle circulates through the ocean, through marine food-webs and other processes, and carbon is locked-away in coastal and marine habitats and deep in ocean sediments. Coastal ecosystems alone sequester more carbon than terrestrial forest per unit area. [...]"

Source: Phys.org

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A New Characterization of the Upper Waters of the central Gulf of México based on Water Mass Hydrographic and Biogeochemical Characteristics

Abstract.

" In the Gulf of Mexico (GoM) at least three near-surface water masses are affected by mesoscale processes that modulate the biogeochemical cycles. Prior studies have presented different classifications of water masses where the greater emphasis was on deep waters and not on the surface waters (σθ < 26 kg m−3), as in this work. Here presents a new classification of water masses in the GoM, based on thermohaline properties and dissolved oxygen (DO) concentration using data from a total of five summer and winter cruises carried out primarily in the central GoM. [...]"

Source: Biogeosciences
Authors: Gabriela Yareli Cervantes-Diaz et al.
DOI: 10.5194/bg-2019-340

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