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Changing carbon-to-nitrogen ratios of organic-matter export under ocean acidification

Abstract.

"Ocean acidification (OA) will affect marine biotas from the organism to the ecosystem level. Yet, the consequences for the biological carbon pump and thereby the oceanic sink for atmospheric CO2 are still unclear. Here we show that OA considerably alters the C/N ratio of organic-matter export (C/Nexport), a key factor determining efficiency of the biological pump. By synthesizing sediment-trap data from in situ mesocosm studies in different marine biomes[...]

 

Source: Nature Climate Change 
Authors: Jan Taucher et al.
DOI:https://doi.org/10.1038/s41558-020-00915-5

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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. 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

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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[...]"

 

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

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Effects of Experimental Ocean Acidification on the Larval Morphology and Metabolism of a Temperate Sparid, Chrysoblephus laticeps

Abstract.

"Ocean acidification is predicted to have widespread impacts on marine species. The early life stages of fishes, being particularly sensitive to environmental deviations, represent a critical bottleneck to recruitment. We investigated the effects of ocean acidification (∆pH = −0.4) on the oxygen consumption and morphometry during the early ontogeny of a commercially important seabream, Chrysoblephus laticeps, up until flexion. Hatchlings appeared to be tolerant to hypercapnic conditions, exhibiting no difference in oxygen consumption or morphometry between treatments, although the yolk reserves were marginally reduced in the low-pH treatment. The preflexion stages appeared[...]"

 

Source: MDPI
Authors: Cuen Muller et al.
DOI: https://doi.org/10.3390/oceans2010002

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The Impacts of Ocean Acidification on Marine Ecosystems and Reliant Human Communities

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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Ocean acidification reduces growth and grazing impact of Antarctic heterotrophic nanoflagellates

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

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Monitoring ocean biogeochemistry with autonomous platforms

Abstract.

"Human activities have altered the state of the ocean, leading to warming, acidification and deoxygenation. These changes impact ocean biogeochemistry and influence ecosystem functions and ocean health. The long-term global effects of these changes are difficult to predict using current satellite sensing and traditional in situ observation techniques. [...]"

Source: Nature Reviews Earth & Environment
Authors: Fei Chai et al.
DOI: 10.1038/s43017-020-0053-y

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Emergent constraint on Arctic Ocean acidification in the twenty-first century

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 (Ωarag) and calcite (Ωcalc). Because of its naturally low Ωarag and Ωcalc (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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Twenty-first century ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary production decline from CMIP6 model projections

Abstract.

"Anthropogenic climate change is projected to lead to ocean warming, acidification, deoxygenation, reductions in near-surface nutrients, and changes to primary production, all of which are expected to affect marine ecosystems. Here we assess projections of these drivers of environmental change over the twenty-first century from Earth system models (ESMs) participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) that were forced under the CMIP6 Shared Socioeconomic Pathways (SSPs). [...]"

Source: Biogeosciences
Authors: Lester Kwiatkowski et al.
DOI: 10.5194/bg-17-3439-2020

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Additive impacts of deoxygenation and acidification threaten marine biota

Abstract.

"Deoxygenation in coastal and open‐ocean ecosystems rarely exists in isolation but occurs concomitantly with acidification. Here, we first combine meta‐data of experimental assessments from across the globe to investigate the potential interactive impacts of deoxygenation and acidification on a broad range of marine taxa. [...]"

Source: Global Change Biology
Authors: Alexandra Steckbauer et al.
DOI: 10.1111/gcb.15252

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