scholarly journals Climate change and ocean acidification impacts on lower trophic levels and the export of organic carbon to the deep ocean

2013 ◽  
Vol 10 (9) ◽  
pp. 5831-5854 ◽  
Author(s):  
A. Yool ◽  
E. E. Popova ◽  
A. C. Coward ◽  
D. Bernie ◽  
T. R. Anderson
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Ocean Acidification ◽  
21St Century ◽  
Trophic Level ◽  
Large Scale ◽  
World Ocean ◽  
Trophic Levels ◽  
The Arctic ◽  
Marine Biota

Abstract. Most future projections forecast significant and ongoing climate change during the 21st century, but with the severity of impacts dependent on efforts to restrain or reorganise human activity to limit carbon dioxide (CO2) emissions. A major sink for atmospheric CO2, and a key source of biological resources, the World Ocean is widely anticipated to undergo profound physical and – via ocean acidification – chemical changes as direct and indirect results of these emissions. Given strong biophysical coupling, the marine biota is also expected to experience strong changes in response to this anthropogenic forcing. Here we examine the large-scale response of ocean biogeochemistry to climate and acidification impacts during the 21st century for Representative Concentration Pathways (RCPs) 2.6 and 8.5 using an intermediate complexity global ecosystem model, MEDUSA-2.0. The primary impact of future change lies in stratification-led declines in the availability of key nutrients in surface waters, which in turn leads to a global decrease (1990s vs. 2090s) in ocean productivity (−6.3%). This impact has knock-on consequences for the abundance of the low trophic level biogeochemical actors modelled by MEDUSA-2.0 (−5.8%), and these would be expected to similarly impact higher trophic level elements such as fisheries. Related impacts are found in the flux of organic material to seafloor communities (−40.7% at 1000 m), and in the volume of ocean suboxic zones (+12.5%). A sensitivity analysis removing an acidification feedback on calcification finds that change in this process significantly impacts benthic communities, suggesting that a~better understanding of the OA-sensitivity of calcifying organisms, and their role in ballasting sinking organic carbon, may significantly improve forecasting of these ecosystems. For all processes, there is geographical variability in change – for instance, productivity declines −21% in the Atlantic and increases +59% in the Arctic – and changes are much more pronounced under RCP 8.5 than the RCP 2.6 scenario.

scholarly journals Climate change and ocean acidification impacts on lower trophic levels and the export of organic carbon to the deep ocean

2013 ◽  
Vol 10 (2) ◽  
pp. 3455-3522 ◽  
Author(s):  
A. Yool ◽  
E. E. Popova ◽  
A. C. Coward ◽  
D. Bernie ◽  
T. R. Anderson
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Ocean Acidification ◽  
21St Century ◽  
Trophic Level ◽  
Large Scale ◽  
World Ocean ◽  
Deep Ocean ◽  
Trophic Levels ◽  
Marine Biota

Abstract. Most future projections forecast significant and ongoing climate change during the 21st century, but with the severity of impacts dependent on efforts to restrain or reorganise human activity to limit carbon dioxide (CO2) emissions. A major sink for atmospheric CO2, and a key source of biological resources, the World Ocean is widely anticipated to undergo profound physical and – via ocean acidification – chemical changes as direct and indirect results of these emissions. Given strong biophysical coupling, the marine biota is also expected to experience strong changes in response to this anthropogenic forcing. Here we examine the large-scale response of ocean biogeochemistry to climate and acidification impacts during the 21st century for Representative Concentration Pathways (RCPs) 2.6 and 8.5 using an intermediate complexity global ecosystem model, Medusa–2.0. The primary impact of future change lies in stratification-led declines in the availability of key nutrients in surface waters, which in turn leads to a global decrease (1990s vs. 2090s) in ocean productivity (−6.3%). This impact has knock-on consequences for the abundances of the low trophic level biogeochemical actors modelled by Medusa–2.0 (−5.8%), and these would be expected to similarly impact higher trophic level elements such as fisheries. Related impacts are found in the flux of organic material to seafloor communities (−40.7% at 1000 m), and in the volume of ocean suboxic zones (+12.5%). A sensitivity analysis removing an acidification feedback on calcification finds that change in this process significantly impacts benthic communities, suggesting that a better understanding of the OA-sensitivity of calcifying organisms, and their role in ballasting sinking organic carbon, may significantly improve forecasting of these ecosystems. For all processes, there is geographical variability in change, and changes are much more pronounced under RCP 8.5 than the RCP 2.6 scenario.

scholarly journals Drivers of trophic amplification of ocean productivity trends in a changing climate

2014 ◽  
Vol 11 (24) ◽  
pp. 7125-7135 ◽  
Author(s):  
C. A. Stock ◽  
J. P. Dunne ◽  
J. G. John
Keyword(s):  
Food Web ◽  
21St Century ◽  
Trophic Level ◽  
Net Primary Production ◽  
Trophic Levels ◽  
The Arctic ◽  
Phytoplankton Production ◽  
Planktonic Food ◽  
Projected Changes ◽  
Zooplankton Growth

Abstract. Pronounced projected 21st century trends in regional oceanic net primary production (NPP) raise the prospect of significant redistributions of marine resources. Recent results further suggest that NPP changes may be amplified at higher trophic levels. Here, we elucidate the role of planktonic food web dynamics in driving projected changes in mesozooplankton production (MESOZP) found to be, on average, twice as large as projected changes in NPP by the latter half of the 21st century under a high emissions scenario in the Geophysical Fluid Dynamics Laboratory's ESM2M–COBALT (Carbon, Ocean Biogeochemistry and Lower Trophics) earth system model. Globally, MESOZP was projected to decline by 7.9% but regional MESOZP changes sometimes exceeded 50%. Changes in three planktonic food web properties – zooplankton growth efficiency (ZGE), the trophic level of mesozooplankton (MESOTL), and the fraction of NPP consumed by zooplankton (zooplankton–phytoplankton coupling, ZPC), explain the projected amplification. Zooplankton growth efficiencies (ZGE) changed with NPP, amplifying both NPP increases and decreases. Negative amplification (i.e., exacerbation) of projected subtropical NPP declines via this mechanism was particularly strong since consumers in the subtropics have limited surplus energy above basal metabolic costs. Increased mesozooplankton trophic level (MESOTL) resulted from projected declines in large phytoplankton production. This further amplified negative subtropical NPP declines but was secondary to ZGE and, at higher latitudes, was often offset by increased ZPC. Marked ZPC increases were projected for high-latitude regions experiencing shoaling of deep winter mixing or decreased winter sea ice – both tending to increase winter zooplankton biomass and enhance grazer control of spring blooms. Increased ZPC amplified projected NPP increases in the Arctic and damped projected NPP declines in the northwestern Atlantic and Southern Ocean. Improved understanding of the physical and biological interactions governing ZGE, MESOTL and ZPC is needed to further refine estimates of climate-driven productivity changes across trophic levels.

scholarly journals A temporal shift in trophic diversity among a predator assemblage in a warming Arctic

2018 ◽  
Vol 5 (10) ◽  
pp. 180259 ◽  
Author(s):  
David J. Yurkowski ◽  
Nigel E. Hussey ◽  
Steven H. Ferguson ◽  
Aaron T. Fisk
Keyword(s):  
Climate Change ◽  
Trophic Level ◽  
Trophic Ecology ◽  
Trophic Levels ◽  
High Trophic Level ◽  
The Arctic ◽  
Delphinapterus Leucas ◽  
Greenland Halibut ◽  
Temporal Shift ◽  
Predator Species

Climate change is leading to northward shifts in species distributions that is altering interspecific interactions at low- and mid-trophic levels. However, little attention has been focused on the effects of redistributions of species on the trophic ecology of a high trophic-level predator assemblage. Here, during a 22-year period (1990–2012) of increasing sea temperature (1.0°C) and decreasing sea ice extent (12%) in Cumberland Sound, Nunavut, Canada, we examined the trophic structure of a near-apex predator assemblage before (1990–2002) and after (2005–2012) an increase in the availability of capelin—generally an indicator species in colder marine environments for a warming climate. Stable isotopes (δ 13 C and δ 15 N) were used in a Bayesian framework to assess shifts in diet, niche size and community-wide metrics for beluga whales ( Delphinapterus leucas ), ringed seals ( Pusa hispida ), Greenland halibut ( Reinhardtius hippoglossoides ) and anadromous Arctic char ( Salvelinus alpinus ). After 2005, consumption of forage fish increased for all predator species, suggesting diet flexibility with changing abiotic and biotic conditions. An associated temporal shift from a trophically diverse to a trophically redundant predator assemblage occurred where predators now play similar trophic roles by consuming prey primarily from the pelagic energy pathway. Overall, these long-term ecological changes signify that trophic shifts of a high trophic-level predator assemblage associated with climate change have occurred in the Arctic food web.

scholarly journals Variability in nitrogen-derived trophic levels of Arctic marine biota

Polar Biology ◽  
2020 ◽  
Author(s):  
Renske P. J. Hoondert ◽  
Nico W. van den Brink ◽  
Martine J. van den Heuvel-Greve ◽  
Ad M. J. Ragas ◽  
A. Jan Hendriks
Keyword(s):  
Stable Isotopes ◽  
Enrichment Factors ◽  
Trophic Levels ◽  
The Arctic ◽  
Marine Biota ◽  
Arctic Ecosystems ◽  
Arctic Species ◽  
Single Region ◽  
Benthic Food ◽  
Species Specific

AbstractStable isotopes are often used to provide an indication of the trophic level (TL) of species. TLs may be derived by using food-web-specific enrichment factors in combination with a representative baseline species. It is challenging to sample stable isotopes for all species, regions and seasons in Arctic ecosystems, e.g. because of practical constraints. Species-specific TLs derived from a single region may be used as a proxy for TLs for the Arctic as a whole. However, its suitability is hampered by incomplete knowledge on the variation in TLs. We quantified variation in TLs of Arctic species by collating data on stable isotopes across the Arctic, including corresponding fractionation factors and baseline species. These were used to generate TL distributions for species in both pelagic and benthic food webs for four Arctic areas, which were then used to determine intra-sample, intra-study, intra-region and inter-region variation in TLs. Considerable variation in TLs of species between areas was observed. This is likely due to differences in parameter choice in estimating TLs (e.g. choice of baseline species) and seasonal, temporal and spatial influences. TLs between regions were higher than the variance observed within regions, studies or samples. This implies that TLs derived within one region may not be suitable as a proxy for the Arctic as a whole. The TL distributions derived in this study may be useful in bioaccumulation and climate change studies, as these provide insight in the variability of trophic levels of Arctic species.

scholarly journals Finding the VOICE: organic carbon isotope chemostratigraphy of Late Jurassic – Early Cretaceous Arctic Canada

2019 ◽  
Vol 157 (10) ◽  
pp. 1643-1657 ◽  
Author(s):  
Jennifer M. Galloway ◽  
Madeleine L. Vickers ◽  
Gregory D. Price ◽  
Terence Poulton ◽  
Stephen E. Grasby ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Isotope ◽  
High Latitude ◽  
Large Scale ◽  
The Arctic ◽  
Sudden Increase ◽  
Arctic Canada ◽  
Contributing Factors ◽  
Compositional Evolution ◽  
Sverdrup Basin

AbstractA new carbon isotope record for two high-latitude sedimentary successions that span the Jurassic–Cretaceous boundary interval in the Sverdrup Basin of Arctic Canada is presented. This study, combined with other published Arctic data, shows a large negative isotopic excursion of organic carbon (δ13Corg) of 4‰ (V-PDB) and to a minimum of −30.7‰ in the probable middle Volgian Stage. This is followed by a return to less negative values of c. −27‰. A smaller positive excursion in the Valanginian Stage of c. 2‰, reaching maximum values of −24.6‰, is related to the Weissert Event. The Volgian isotopic trends are consistent with other high-latitude records but do not appear in δ13Ccarb records of Tethyan Tithonian strata. In the absence of any obvious definitive cause for the depleted δ13Corg anomaly, we suggest several possible contributing factors. The Sverdrup Basin and other Arctic areas may have experienced compositional evolution away from open-marine δ13C values during the Volgian Age due to low global or large-scale regional sea levels, and later become effectively coupled to global oceans by Valanginian time when sea level rose. A geologically sudden increase in volcanism may have caused the large negative δ13Corg values seen in the Arctic Volgian records but the lack of precise geochronological age control for the Jurassic–Cretaceous boundary precludes direct comparison with potentially coincident events, such as the Shatsky Rise. This study offers improved correlation constraints and a refined C-isotope curve for the Boreal region throughout latest Jurassic and earliest Cretaceous time.

The Frontier Research System for Global Change—The International Arctic Research Center (Frontier-IARC): its Origin and Tentative Science Plan

1999 ◽  
Vol 33 (1) ◽  
pp. 81-84
Author(s):  
Jinro Ukila ◽  
Moloyoshi Ikeda
Keyword(s):  
Climate Change ◽  
Global Change ◽  
Global Climate Change ◽  
Large Scale ◽  
Global Climate ◽  
Research Effort ◽  
Arctic Region ◽  
Research Center ◽  
The Arctic ◽  
Research System

The Frontier Research System for Global Change—the International Arctic Research Center (Frontier-IARC) is a research program funded by the Frontier Research System for Global Change. The program is jointly run under a cooperative agreement between the Frontier Research System for Global Change and the University of Alaska Fairbanks. The aim of the program is to understand the role of the Arctic region in global climate change. The program concentrates its research effort initially on the areas of air-sea-ice interactions, bio-geochemical processes and the ecosystem. To understand the arctic climate system in the context of global climate change, we focus on mechanisms controlling arctic-subarctic interactions, and identify three key components: the freshwater balance, the energy balance, and the large-scale atmospheric processes. Knowledge of details of these components and their interactions will be gained through long-term monitoring, process studies, and modeling; our focus will be on the latter two categories.

scholarly journals Are Arctic Ocean ecosystems exceptionally vulnerable to global emissions of mercury? A call for emphasised research on methylation and the consequences of climate change

2010 ◽  
Vol 7 (2) ◽  
pp. 133 ◽  
Author(s):  
R. W. Macdonald ◽  
L. L. Loseto
Keyword(s):  
Climate Change ◽  
Arctic Ocean ◽  
Food Webs ◽  
Deposition Process ◽  
The Arctic ◽  
Marine Biota ◽  
Mercury Deposition ◽  
Photochemical Process ◽  
The Arctic Ocean ◽  
Emission Controls

Environmental context. Mercury is a global contaminant that has entered Arctic food webs in sufficient quantity to put at risk the health of top predators and humans that consume them. Recent research has discovered a photochemical process unique to the Arctic that leads to mercury deposition on frozen surfaces after polar sunrise, but the connection between mercury deposition and entry into food webs remains tenuous and poorly understood. We propose here that the Arctic Ocean’s sensitivity to the global mercury cycle depends far more on neglected post-deposition processes that lead to methylation within the ice–ocean system, and the vulnerability of these processes to changes occurring in the cryosphere. Abstract. Emissions, atmospheric transport and deposition have formed the emphasis of recent research to understand Hg trends in Arctic marine biota, with the expressed objective of predicting how biotic trends might respond to emission controls. To answer the question of whether the Arctic Ocean might be especially vulnerable to global mercury (Hg) contamination and how biota might respond to emission controls requires a distinction between the supply of Hg from source regions and the processes within the Arctic Ocean that sequester and convert mercury to monomethyl Hg (MeHg). Atmospheric Mercury Depletion Events (AMDEs) provide a unique Hg deposition process in the Arctic; however, AMDEs have yet to be linked quantitatively with Hg uptake in marine food webs. The difficulty in implicating AMDEs or emissions to biotic trends lie in the ocean where several poorly understood processes lead to MeHg production and biomagnification. We propose that sensitivity of the Arctic Ocean’s ecosystem to Hg lies not so much in the deposition process as in methylation processes within the ocean, Hg inputs from large drainage basins, and the vulnerability these to climate change. Future research needs to be better balanced across the entire Hg cycle.

scholarly journals Projected loss of soil organic carbon in temperate agricultural soils in the 21st century: effects of climate change and carbon input trends

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Martin Wiesmeier ◽  
Christopher Poeplau ◽  
Carlos A. Sierra ◽  
Harald Maier ◽  
Cathleen Frühauf ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
21St Century ◽  
Agricultural Soils

scholarly journals Food web structure of the epibenthic community at the sea ice edge in Baffin Bay, Canada

2018 ◽  
Author(s):  
Gustavo Yunda-Guarin ◽  
Philippe Archambault ◽  
Guillaume Massé ◽  
Christian Nozais
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Food Web ◽  
Trophic Levels ◽  
The Arctic ◽  
Feeding Guilds ◽  
Food Web Structure ◽  
Baffin Bay ◽  
Ice Edge ◽  
Sea Ice Edge

In polar areas, the pelagic-benthic coupling plays a fundamental role in ensuring organic matter flow across depths and trophic levels. Climate change impacts the Arctic’s physical environment and ecosystem functioning, affecting the sequestration of carbon, the structure and efficiency of the benthic food web and its resilience.In the Arctic Ocean, highest atmospheric warming tendencies (by ~0.5°C) occur in the east of Baffin Bay making this area an ideal site to study the effects of climate change on benthic communities. We sampled epibenthic organisms at 13 stations bordering the sea ice between June and July 2016. The epibenthic taxonomic composition was identified and grouped by feeding guilds. Isotopic signatures (δ13C - δ15N), trophic levels and trophic separation and redundancy were measured and quantified at each station. In the light of the results obtained, the stability of the benthic community in the Baffin Bay at the sea ice edge is discussed.

Sign in / Sign up

Export Citation Format

Share Document