Polar Regions

Cambridge University Press eBooks, Journal Year: 2023, Volume and Issue: unknown, P. 2319 - 2368

Published: June 22, 2023

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Language: Английский

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Status, Change, and Futures of Zooplankton in the Southern Ocean

Frontiers in Ecology and Evolution, Journal Year: 2022, Volume and Issue: 9

Published: June 17, 2022

In the Southern Ocean, several zooplankton taxonomic groups, euphausiids, copepods, salps and pteropods, are notable because of their biomass abundance roles in maintaining food webs ecosystem structure function, including provision globally important services. These groups consumers microbes, primary secondary producers, prey for fishes, cephalopods, seabirds, marine mammals. providing link between production, higher trophic levels these taxa influence energy flows, biological production biomass, biogeochemical cycles, carbon flux web interactions thereby modulating functioning ecosystems. Additionally, Antarctic krill ( Euphausia superba ) various fish species harvested by international fisheries. Global local drivers change expected to affect dynamics key species, which may have potentially profound wide-ranging implications Ocean ecosystems services they provide. Here we assess current understanding dominant metazoan within other euphausiid, copepod, salp pteropod species. We provide a systematic overview observed potential future responses changing functional relationships impact them. To support assessments conservation management strategies, also identify priorities research.

Language: Английский

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Biological responses to change in Antarctic sea ice habitats

Frontiers in Ecology and Evolution, Journal Year: 2023, Volume and Issue: 10

Published: Jan. 23, 2023

Sea ice is a key habitat in the high latitude Southern Ocean and predicted to change its extent, thickness duration coming decades. The sea-ice cover instrumental mediating ocean–atmosphere exchanges provides an important substrate for organisms from microbes algae predators. Antarctic krill, Euphausia superba, reliant on sea during phases of life cycle, particularly larval stages, food refuge their predators, while other small grazers, including copepods amphipods, either live brine channel system or find shelter at ice-water interface gaps between rafted blocks. Fish, such as silverfish Pleuragramma antarcticum , use platelet (loosely-formed frazil crystals) essential hatching nursery ground. In this paper, we apply framework Marine Ecosystem Assessment (MEASO) review current knowledge about relationships associated primary production secondary consumers, status drivers ocean. We then qualitative network modelling explore possible responses lower trophic level biota different perturbations, warming air ocean temperatures, increased storminess reduced annual duration. This shows that pelagic algae, copepods, krill fish are likely decrease response temperatures duration, salp populations will increase under conditions number days >0°C. Differences these pressures five MEASO sectors were also explored. Greater impacts environmental ice-related occurring presently found West East Pacific (notably Ross western Peninsula), with flow-on effects wider ecosystem. All expected be impacted over Finally, highlight priorities future biological research address field.

Language: Английский

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New insights into the Weddell Sea ecosystem applying a quantitative network approach

Ocean science, Journal Year: 2024, Volume and Issue: 20(1), P. 141 - 153

Published: Feb. 5, 2024

Abstract. Network approaches can shed light on the structure and stability of complex marine communities. In recent years, such have been successfully applied to study polar ecosystems, improving our knowledge how they might respond ongoing environmental changes. The Weddell Sea is one most studied ecosystems outside Antarctic Peninsula in Southern Ocean. Yet, few studies consider known complexity food web, which its current form comprises 490 species 16 041 predator–prey interactions. Here we analysed focusing trophic interactions that underpin ecosystem stability. We estimated strength for each interaction characterised position web using unweighted weighted properties, species' roles with respect web. found distribution (IS) at level asymmetric, many weak strong ones. detected a positive relationship between median IS two properties (i.e. total number interactions). also only possess key positions terms These are by high IS, middle level, relatively interactions, low similarity. this study, integrated information, enabling more complete assessment function Our results provide new insights, important development effective policies management strategies, particularly given initiative implement protected area (MPA) Sea.

Language: Английский

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Developing a Southern Ocean Marine Ecosystem Model Ensemble To Assess Climate Risks and Uncertainties

Authorea (Authorea), Journal Year: 2024, Volume and Issue: unknown

Published: May 15, 2024

Climate change could irreversibly modify Southern Ocean ecosystems. Marine ecosystem model (MEM) ensembles can assist policy making by projecting future changes and allowing the evaluation assessment of alternative management approaches. However, projected in total consumer biomass from Fisheries Ecosystem Model Intercomparison Project (FishMIP) global MEM ensemble highlight an uncertain for Ocean, indicating need a region-specific ensemble. A large source uncertainty originates Earth system models (ESMs) used to force FishMIP models, particularly lower trophic level sea ice coverage. To build confidence regional MEMs as ecosystem-based tools changing climate that better account uncertainty, we propose development Ensemble (SOMEME) contributing 2.0 intercomparison initiative. One challenges hampering progress is achieving balance standardised inputs with relevance. As first step, design SOMEME simulation protocol, builds on extends existing framework, stages include: detailed skill forcing variables regions, extension fishing data include whaling, new simulations assess ecological links sea-ice processes candidate MEMs. These extensions will help advance assessments urgently needed impacts

Language: Английский

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Individual diet variability shapes the architecture of Antarctic benthic food webs

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: May 29, 2024

Abstract Antarctic biodiversity is affected by seasonal sea-ice dynamics driving basal resource availability. To (1) determine the role of intraspecific dietary variability in structuring benthic food webs sustaining biodiversity, and (2) understand how position topologically central species vary with cover, single individuals’ diets were studied isotopic analysis before breakup afterwards. Isotopic trophospecies (or Trophic Units) investigated reconstructed using Bayesian Mixing Models. As nodes, these used either ITUs regardless their taxonomic membership (ITU-webs) or assigned to (population-webs). Both compared taxonomic-webs based on taxa mean values. Higher availability after led simpler community structure, lower connectance linkage density. Intra-population diet compartmentalisation crucial determining showing population-webs be more complex, stable robust loss than taxonomic-webs. The core web, representing minimal ‘skeleton’ that expands opportunistically while maintaining web stability changing availability, was also identified. Central nodes included sea-urchin Sterechinus neumayeri bivalve Adamussium colbecki , whose described unprecedented detail. represent factors underlying Antarctica’s rich persistence.

Language: Английский

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Southern Ocean food-webs and climate change: A short review and future directions

PLOS Climate, Journal Year: 2024, Volume and Issue: 3(3), P. e0000358 - e0000358

Published: March 11, 2024

Food-webs are a critical feature of ecosystems and help us understand how communities will respond to climate change. The Southern Ocean is facing rapid accelerating changes due Though having evolved in an isolated somewhat extreme environment, biodiversity food-webs among the most vulnerable. Here, we review 1) current knowledge on food-webs; 2) methods study 3) assessment future impacts change 4) gaps; 5) role Early Career Researchers (ECRs) studies. Most come from pelagic both at macro- microbial levels. Modelling diet studies individual species major contributors food-web knowledge. These revealed short food-web, predominantly sustained by Antarctic Krill ( Euphausia superba ). Additionally, alternative pathways exist, involving other krill species, fish, squid, which play equally important roles connecting primary producers with top predators. Advantages disadvantages several techniques used were identified, classical analyses stomach contents, scats, or boluses recent approaches such as metabarcoding trophic-biomarkers. Observations show that can impact different ways. As example, smaller phytoplankton lengthen increasing assimilation losses and/or changing nutrient cycles. Future need focus benthic-dominated benthopelagic coupling. Furthermore, research during winter season below ice-shelves needed these areas may crucial functioning this ecosystem. ECRs significant advancing their willingness for interdisciplinary collaboration proficiency employing various methodologies, contributing construction high-resolution food-webs.

Language: Английский

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Detecting the invisible through DNA metabarcoding: The role of gelatinous taxa in the diet of two demersal Antarctic key stone fish species (Notothenioidei)

Environmental DNA, Journal Year: 2024, Volume and Issue: 6(3)

Published: May 1, 2024

Abstract Gelatinous zooplankton (GZP), i.e., ctenophores, cnidarian medusae, chaetognaths, appendicularians and salps, are considered climate change winners. This becomes particularly obvious in the Southern Ocean, which has undergone a significant shift from krill‐based to salp‐based ecosystem over last decades. A better knowledge on role of gelatinous invertebrates as prey is needed predict impact such shift. Until recently, GZP was “trophic dead end”. However, their true importance diets remained unresolved due rapid digestion watery soft tissues predators' stomachs. In this study, we want validate paradigm being “survival food” be “regular” item for two demersal fish species ( Notothenia rossii N. coriiceps ) Potter Cove, South Shetland Islands, using multimarker (COI 18S) metabarcoding approach. We found that taxa commonly occurred both species, represented by pelagic tunicates (appendicularians, salps), cnidarians, chaetognaths ctenophores. Salps were most abundant group, preyed upon each individual reaching 98.7% relative read abundance 18S. recovered wide range different diets, primary producers highly invertebrates, thus nototheniid can regarded “natural samplers” study. Finally, point out approaches broad ecological assessments, given differential amplification sequencing success markers specific groups unequal taxonomic coverage reference databases. The output marker complementary, since an important only detected with 18S, while other (e.g., Arthropoda) higher resolution COI.

Language: Английский

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Developing a Southern Ocean Marine Ecosystem Model Ensemble to Assess Climate Risks and Uncertainties

Earth s Future, Journal Year: 2025, Volume and Issue: 13(3)

Published: March 1, 2025

Abstract Climate change could irreversibly modify Southern Ocean ecosystems. Marine ecosystem model (MEM) ensembles can assist policy making by projecting future changes and allowing the evaluation assessment of alternative management approaches. However, projected in total consumer biomass from Fisheries Ecosystem Model Intercomparison Project (FishMIP) global MEM ensemble highlight an uncertain for Ocean, indicating need a region‐specific ensemble. A large source uncertainty originates Earth system models used to force FishMIP models, particularly lower trophic level sea‐ice coverage. To build confidence regional MEMs as ecosystem‐based tools changing climate that better account uncertainty, we propose development Ensemble (SOMEME) contributing 2.0 intercomparison initiative. One challenges hampering progress is achieving balance standardised inputs with relevance. As first step, design SOMEME simulation protocol, builds on extends existing framework, stages include: detailed skill forcing variables regions, extension fishing data include whaling, new simulations assess ecological links processes candidate MEMs. These extensions will help advance assessments urgently needed impacts

Language: Английский

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Composition and Distribution of Plankton Communities in the Atlantic Sector of the Southern Ocean

Diversity, Journal Year: 2022, Volume and Issue: 14(11), P. 923 - 923

Published: Oct. 28, 2022

In recent decades, the waters off Antarctic Peninsula and surrounding region have undergone a significant transformation due to global climate change affecting structure distribution of pelagic fauna. Here, we present results our study on taxonomic composition quantitative plankton communities in Bransfield Strait, Sound, Powell Basin Weddell Sea, South Orkney Islands during austral summer 2022. A slight warming Transitional Zonal Water with Sea influence (TWW) an increase its area was detected. Among communities, three groups were found be most abundant: copepods Calanoides acutus, Metridia gerlachei, Oithona spp., salpa Salpa thompsoni, krill Euphausia superba. Euphausiids cases low abundance, species diversity, biomass. studied region, amount S. thompsoni euphausiid Thysanoessa macrura expansion their observed. Significant structural shifts phytoplankton manifested themselves changes forage base. The fauna is affected by combination environmental abiotic factors, which water temperature main one. obtained allowed us assume that further ocean may lead reduction number size population successive replacement salps other euphausiids are more resistant fluctuations desalination.

Language: Английский

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