The Effects of Combined Ocean Acidification and Nanoplastic Exposures on the Embryonic Development of Antarctic Krill

In aquatic environments, plastic pollution occurs concomitantly with anthropogenic climate stressors such as ocean acidification. Within the Southern Ocean, Antarctic krill (Euphausia Superba) support many marine predators and play a key role in the biogeochemical cycle. Ocean acidification and plastic pollution have been acknowledged to hinder Antarctic krill development and physiology in singularity, however potential multi-stressor effects of plastic particulates coupled with ocean acidification are unexplored. Furthermore, Antarctic krill may be especially vulnerable to plastic pollution due to their close association with sea-ice, a known plastic sink. Here, we investigate the behaviour of nanoplastic [spherical, aminated (NH2), and yellow-green fluorescent polystyrene nanoparticles] in Antarctic seawater and explore the single and combined effects of nanoplastic (160 nm radius, at a concentration of 2.5 μg ml–1) and ocean acidification (pCO2 ∼900, pHT 7.7) on the embryonic development of Antarctic krill. Gravid female krill were collected in the Atlantic sector of the Southern Ocean (North Scotia Sea). Produced eggs were incubated at 0.5 °C in four treatments (control, nanoplastic, ocean acidification and the multi-stressor scenario of nanoplastic presence, and ocean acidification) and their embryonic development after 6 days, at the incubation endpoint, was determined. We observed that negatively charged nanoplastic particles suspended in seawater from the Scotia Sea aggregated to sizes exceeding the nanoscale after 24 h (1054.13 ± 53.49 nm). Further, we found that the proportion of embryos developing through the early stages to reach at least the limb bud stage was highest in the control treatment (21.84%) and lowest in the multi-stressor treatment (13.17%). Since the biological thresholds to any stressors can be altered by the presence of additional stressors, we propose that future nanoplastic ecotoxicology studies should consider the changing global ocean under future climate scenarios for assessments of their impact and highlight that determining the behaviour of nanoplastic particles used in incubation studies is critical to determining their toxicity.

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The impact of nanoplastic on embryonic development of Antarctic krill in current and future acidified conditions of the Southern Ocean

10.5194/egusphere-egu21-11332 ◽

2021 ◽

Author(s):

Emily Rowlands ◽

Tamara Galloway ◽

Matthew Cole ◽

Ceri Lewis ◽

Victoria Peck ◽

...

Keyword(s):

Embryonic Development ◽

Southern Ocean ◽

Antarctic Krill ◽

Multiple Stressors ◽

Combined Treatment ◽

Limb Bud ◽

Atlantic Sector ◽

Antarctic Species ◽

Significant Difference ◽

The Impact

Antarctic krill (Euphausia superba), hereafter krill, are pivotal to the Antarctic marine ecosystem, forming the base of a highly productive system and contributing significantly to the biogeochemical cycle. The negative effects of anthropogenic climate stressors amplified in the Southern Ocean such as rapid warming and ocean acidification (OA) have been acknowledged for krill. Less explored is the impact of increasing plastic pollution, particularly in conditions that reflect the likely future Southern Ocean environment. We hypothesise that krill have heightened vulnerability to multi-stressor scenarios due to their physiological and behavioural traits coupled with rapid environmental changes of their Antarctic habitats. Here, we investigate the single and combined effects of nanoplastic (NP; spherical, aminated (NP-NH2), yellow-green, fluorescent polystyrene nanoparticles) and OA (pCO2-manipulated seawater, pH 7.7) on the embryonic development of krill eggs. Krill were collected in the Scotia Sea within the Atlantic sector of the Southern Ocean in austral summer 2019. Eggs from a single female were incubated in seawater at 0.5 &#176;C for 6 days with three treatments: (i) with 0.16 &#956;m NP, (ii) in acidified conditions, and (iii) with a combined treatment of NP (0.16&#956;m) and acidification. All NP treatments were at a concentration of 2.5&#956;g/ml. We found that exposure to the NP-OA multi-stress treatment negatively impacted the development of embryos, decreasing the probability of reaching the limb bud stage by 9% compared with the control, whilst no significant difference was observed for the singular NP or OA treatments. This preliminary study supports our hypothesis regarding the potential impacts of multiple stressors on vulnerable embryonic stages of this ecologically critical Antarctic species.

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Coccolithophore populations and their contribution to carbonate export during an annual cycle in the Australian sector of the Antarctic zone

Biogeosciences ◽

10.5194/bg-15-1843-2018 ◽

2018 ◽

Vol 15 (6) ◽

pp. 1843-1862 ◽

Cited By ~ 7

Author(s):

Andrés S. Rigual Hernández ◽

José A. Flores ◽

Francisco J. Sierro ◽

Miguel A. Fuertes ◽

Lluïsa Cros ◽

...

Keyword(s):

Southern Ocean ◽

Ocean Acidification ◽

Deep Ocean ◽

Sediment Traps ◽

Global Ocean ◽

Field Observations ◽

Scotia Sea ◽

Allochthonous Species ◽

Circumpolar Current ◽

The Antarctic

Abstract. The Southern Ocean is experiencing rapid and relentless change in its physical and biogeochemical properties. The rate of warming of the Antarctic Circumpolar Current exceeds that of the global ocean, and the enhanced uptake of carbon dioxide is causing basin-wide ocean acidification. Observational data suggest that these changes are influencing the distribution and composition of pelagic plankton communities. Long-term and annual field observations on key environmental variables and organisms are a critical basis for predicting changes in Southern Ocean ecosystems. These observations are particularly needed, since high-latitude systems have been projected to experience the most severe impacts of ocean acidification and invasions of allochthonous species. Coccolithophores are the most prolific calcium-carbonate-producing phytoplankton group playing an important role in Southern Ocean biogeochemical cycles. Satellite imagery has revealed elevated particulate inorganic carbon concentrations near the major circumpolar fronts of the Southern Ocean that can be attributed to the coccolithophore Emiliania huxleyi. Recent studies have suggested changes during the last decades in the distribution and abundance of Southern Ocean coccolithophores. However, due to limited field observations, the distribution, diversity and state of coccolithophore populations in the Southern Ocean remain poorly characterised. We report here on seasonal variations in the abundance and composition of coccolithophore assemblages collected by two moored sediment traps deployed at the Antarctic zone south of Australia (2000 and 3700 m of depth) for 1 year in 2001–2002. Additionally, seasonal changes in coccolith weights of E. huxleyi populations were estimated using circularly polarised micrographs analysed with C-Calcita software. Our findings indicate that (1) coccolithophore sinking assemblages were nearly monospecific for E. huxleyi morphotype B/C in the Antarctic zone waters in 2001–2002; (2) coccoliths captured by the traps experienced weight and length reduction during summer (December–February); (3) the estimated annual coccolith weight of E. huxleyi at both sediment traps (2.11 ± 0.96 and 2.13 ± 0.91 pg at 2000 and 3700 m) was consistent with previous studies for morphotype B/C in other Southern Ocean settings (Scotia Sea and Patagonian shelf); and (4) coccolithophores accounted for approximately 2–5 % of the annual deep-ocean CaCO3 flux. Our results are the first annual record of coccolithophore abundance, composition and degree of calcification in the Antarctic zone. They provide a baseline against which to monitor coccolithophore responses to changes in the environmental conditions expected for this region in coming decades.

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Will krill fare well under Southern Ocean acidification?

Biology Letters ◽

10.1098/rsbl.2010.0777 ◽

2010 ◽

Vol 7 (2) ◽

pp. 288-291 ◽

Cited By ~ 67

Author(s):

So Kawaguchi ◽

Haruko Kurihara ◽

Robert King ◽

Lillian Hale ◽

Thomas Berli ◽

...

Keyword(s):

Embryonic Development ◽

Southern Ocean ◽

Ocean Acidification ◽

Early Development ◽

Antarctic Krill ◽

Sea Water ◽

Depth Range ◽

Response Relationship ◽

Larval Behaviour ◽

Key Species

Antarctic krill embryos and larvae were experimentally exposed to 380 (control), 1000 and 2000 µatm p CO 2 in order to assess the possible impact of ocean acidification on early development of krill. No significant effects were detected on embryonic development or larval behaviour at 1000 µatm p CO 2 ; however, at 2000 µatm p CO 2 development was disrupted before gastrulation in 90 per cent of embryos, and no larvae hatched successfully. Our model projections demonstrated that Southern Ocean sea water p CO 2 could rise up to 1400 µatm in krill's depth range under the IPCC IS92a scenario by the year 2100 (atmospheric p CO 2 788 µatm). These results point out the urgent need for understanding the p CO 2 -response relationship for krill developmental and later stages, in order to predict the possible fate of this key species in the Southern Ocean.

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Ventilation of the abyss in the Atlantic sector of the Southern Ocean

Scientific Reports ◽

10.1038/s41598-021-86043-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Camille Hayatte Akhoudas ◽

Jean-Baptiste Sallée ◽

F. Alexander Haumann ◽

Michael P. Meredith ◽

Alberto Naveira Garabato ◽

...

Keyword(s):

Southern Ocean ◽

Bottom Water ◽

Climate Models ◽

Deep Ocean ◽

Analytical Framework ◽

Weddell Sea ◽

Global Ocean ◽

Shelf Water ◽

Antarctic Bottom Water ◽

Atlantic Sector

AbstractThe Atlantic sector of the Southern Ocean is the world’s main production site of Antarctic Bottom Water, a water-mass that is ventilated at the ocean surface before sinking and entraining older water-masses—ultimately replenishing the abyssal global ocean. In recent decades, numerous attempts at estimating the rates of ventilation and overturning of Antarctic Bottom Water in this region have led to a strikingly broad range of results, with water transport-based calculations (8.4–9.7 Sv) yielding larger rates than tracer-based estimates (3.7–4.9 Sv). Here, we reconcile these conflicting views by integrating transport- and tracer-based estimates within a common analytical framework, in which bottom water formation processes are explicitly quantified. We show that the layer of Antarctic Bottom Water denser than 28.36 kg m$$^{-3}$$ - 3 $$\gamma _{n}$$ γ n is exported northward at a rate of 8.4 ± 0.7 Sv, composed of 4.5 ± 0.3 Sv of well-ventilated Dense Shelf Water, and 3.9 ± 0.5 Sv of old Circumpolar Deep Water entrained into cascading plumes. The majority, but not all, of the Dense Shelf Water (3.4 ± 0.6 Sv) is generated on the continental shelves of the Weddell Sea. Only 55% of AABW exported from the region is well ventilated and thus draws down heat and carbon into the deep ocean. Our findings unify traditionally contrasting views of Antarctic Bottom Water production in the Atlantic sector, and define a baseline, process-discerning target for its realistic representation in climate models.

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Corrigenda to: Standing stock of Antarctic krill (Euphausia superba Dana, 1850) (Euphausiacea) in the Southwest Atlantic sector of the Southern Ocean, 2018–19

Journal of Crustacean Biology ◽

10.1093/jcbiol/ruab071 ◽

2021 ◽

Vol 41 (4) ◽

Author(s):

Bjørn A Krafft ◽

Gavin Macaulay ◽

Georg Skaret ◽

Tor Knutsen ◽

Odd A Bergstad ◽

...

Keyword(s):

Southern Ocean ◽

Antarctic Krill ◽

Standing Stock ◽

Euphausia Superba ◽

Southwest Atlantic ◽

Atlantic Sector ◽

Antarctic Krill Euphausia Superba

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Krill Fishery

Fisheries and Aquaculture ◽

10.1093/oso/9780190865627.003.0006 ◽

2020 ◽

pp. 137-158

Author(s):

So Kawaguchi ◽

Stephen Nicol

Keyword(s):

Southern Ocean ◽

Antarctic Krill ◽

Management Approach ◽

West Antarctica ◽

Southwest Atlantic ◽

Atlantic Sector ◽

Key Species ◽

Technological Developments ◽

Ocean Ecosystem ◽

The Antarctic

Antarctic krill is a key species in the Southern Ocean ecosystem as well as the target for the largest fishery in the Southern Ocean, which has been operating continuously since the early 1970s. The krill fishery began by operating all around the continent but gradually contracted to the West Antarctica in the 1990s, where it is currently concentrated on a few fishing grounds in the Southwest Atlantic sector. This fishery has regained some commercial attraction because of recent technological developments in harvesting and processing. These developments permit the production of high-value products, and the total annual catch has increased to nearly 400,000 t over the last decade. Climate change has already affected the krill fishery, with the reduced winter sea ice in the South Atlantic allowing current fishery operations farther south than what was previously possible. The Antarctic krill fishery is managed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). Its management system is unique in taking into account the state of the ecosystem as well as that of the harvested stock. The establishment of a feedback management approach for this fishery has been the major task for the Scientific Committee of CCAMLR to realize this ecosystem-based management objective. This chapter provides a general introduction to krill biology and ecology, followed by a narrative of the forces that prompted the development of a krill fishery and the current issues that surround its management.

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Scaling of size, shape and surface roughness in Antarctic krill swarms

ICES Journal of Marine Science ◽

10.1093/icesjms/fsz005 ◽

2019 ◽

Vol 76 (4) ◽

pp. 1177-1188

Author(s):

Alexey B Ryabov ◽

Geraint A Tarling

Keyword(s):

Surface Roughness ◽

Southern Ocean ◽

Cross Sections ◽

Antarctic Krill ◽

Major Influence ◽

Atlantic Sector ◽

Size And Shape ◽

Explanatory Factors ◽

Ocean Ecosystem ◽

Log Normal

Abstract Antarctic krill are obligate swarmers and the size and shape of the swarms they form can have a major influence on trophic interactions and biogeochemical fluxes. Parameterizing variability in size and shape is therefore a useful step toward understanding the operation of the Southern Ocean ecosystem. We analyse the relationships between the length L, thickness T, perimeter P, and area A of 4650 vertical cross-sections of open-ocean krill swarms obtained within the Atlantic sector of the Southern Ocean in summer 2003. Our data show that these parameters are tightly interrelated. The thickness T increases on average as L0.67 and has a log-normal distribution within each length class. The perimeter and area scale with L and T as P∼L0.77T and A∼L0.86T0.48. The swarm aspect ratio, T/L, decreases approximately as L-0.32. The surface roughness (defined as P/A) has a weak dependence on swarm length and decreases approximately as T-0.46, which can be explained only by the appearance of indentations and cavities in the swarm shape. Overall, our study finds that there are distinct limits to the size and shape of swarms that Antarctic krill appear to be capable of forming and we explore the potential explanatory factors contributing to these limitations.

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Measurements of total alkalinity and inorganic dissolved carbon in the Atlantic Ocean and adjacent Southern Ocean between 2008 and 2010

Earth System Science Data Discussions ◽

10.5194/essdd-6-621-2013 ◽

2013 ◽

Vol 6 (2) ◽

pp. 621-639

Author(s):

U. Schuster ◽

A. J. Watson ◽

D. C. E. Bakker ◽

A. M. de Boer ◽

E. M. Jones ◽

...

Keyword(s):

Quality Control ◽

Atlantic Ocean ◽

Southern Ocean ◽

Inorganic Carbon ◽

Dissolved Inorganic Carbon ◽

Drake Passage ◽

Total Alkalinity ◽

Global Ocean ◽

Atlantic Sector ◽

Dissolved Carbon

Abstract. Water column dissolved inorganic carbon and total alkalinity were measured during five hydrographic sections in the Atlantic Ocean and Drake Passage. The work was funded through the Strategic Funding Initiative of the UK's Oceans2025 programme, which ran from 2007 to 2012. The aims of this programme were to establish the regional budgets of natural and anthropogenic carbon in the North Atlantic, the South Atlantic, and the Atlantic sector of the Southern Ocean, as well as the rates of change of these budgets. This paper describes the dissolved inorganic carbon and total alkalinity data collected along east-west sections at 55–60° N (Arctic Gateway), 24.5° N, and 24° S in the Atlantic and across two Drake Passage sections. Other hydrographic and biogeochemical parameters were measured during these sections, yet are not covered in this paper. Over 95% of samples taken during the 24.5° N, 24° S, and the Drake Passage sections were analysed onboard and subjected to a 1st level quality control addressing technical and analytical issues. Samples taken during Arctic Gateway were analysed and subjected to quality control back in the laboratory. Complete post-cruise 2nd level quality control was performed using cross-over analysis with historical data in the vicinity of measurements, and data are available through the Carbon Dioxide Information Analysis Center (CDIAC) and are included in the Global Ocean Data Analyses Project, version 2 (GLODAP 2).

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