Life Under Antarctic Pack Ice: A Krill Perspective

Quetin, Langdon B.; Ross, Robin M.

doi:10.5479/si.097884601x.21

Cited by 17 publications

(17 citation statements)

References 73 publications

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“…This concept is supported by the available observations (Spiridonov et al 1985;O'Brien 1987;Marschall 1988;Bergström et al 1990;Spiridonov 1992;Quetin et al 1994Quetin et al , 1996Frazer et al 1997;Lawson et al 2008;Quetin and Ross 2009;Meyer et al 2010). Surveys by remote operating vehicles (ROV) or SCUBA divers in diVerent regions of the Southern Ocean during winter (BransWeld Strait, Lazarev Sea, the WAP region) have only seldom observed adult krill associated with sea ice (Quetin et al 1994(Quetin et al , 1996Frazer et al 1997;Lawson et al 2008;Quetin and Ross 2009;Meyer et al 2010). Net surveys in the Gerlache Strait during winter found maximal krill abundance between 15 and 50 m depth (Nordhausen 1994;Zhou et al 1994).…”

Section: Body Lipid and Protein Utilisationsupporting

confidence: 73%

“…A conceptual model has been developed that links recruitment success to the timing of seasonal sea ice events mediated through availability of food for larvae (Siegel and Loeb 1995;Quetin et al 1996Quetin et al , 2007Quetin and Ross 2009). This concept was developed from investigations on krill in the WAP area but is well supported by data from krill studies in the high sea region of the Lazarev Sea (Meyer et al 2009).…”

Section: Annual Life Cycle In Changing Southern Ocean Environmentmentioning

confidence: 99%

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The overwintering of Antarctic krill, Euphausia superba, from an ecophysiological perspective

2011

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A major aim of this review is to determine which physiological functions are adopted by adults and larvae to survive the winter season with low food supply and their relative importance. A second aim is to clarify the extent to which seasonal variation in larval and adult krill physiology is mediated by environmental factors with a strong seasonality, such as food supply or day light. Experimental studies on adult krill have demonstrated that speciWc physiological adaptations during autumn and winter, such as reduced metabolic rates and feeding activity, are not caused simply by the scarcity of food, as was previously assumed. These adaptations appear to be inXuenced by the local light regime. The physiological functions that larval krill adopt during winter (reduced metabolism, delayed development, lipid utilisation, and variable growth rates) are, in contrast to the adults, under direct control by the available food supply. During winter, the adults often seem to have little association with sea ice (at least until early spring). The larvae, however, feed within sea ice but mainly on the grazers of the ice algal community rather than on the algae themselves. In this respect, a miss-match in timing of the occurrence of the last phytoplankton blooms in autumn and the start of the sea ice formation, as has been increasingly observed in the west Antarctic Peninsula (WAP) region, will impact larval krill development during winter in terms of food supply and consequently the krill stock in this region.

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Section: Body Lipid and Protein Utilisationsupporting

confidence: 73%

Section: Annual Life Cycle In Changing Southern Ocean Environmentmentioning

confidence: 99%

The overwintering of Antarctic krill, Euphausia superba, from an ecophysiological perspective

2011

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“…These bottom ice algal communities are an essential food source for zooplankton over winter (Brierley andreferences therein, Jia et al, 2016), when phytoplankton biomass in the waters beneath the sea ice are very low due to light limitation (Perrin et al, 1987;Legendre et al, 1992;Robins et al, 1995). For example, the phenology of the Antarctic krill, Euphausia superba, a keystone organism in SO food webs, is integrally liked to sea ice and seasonality, largely due to its being a refuge and source of algal nutrition over winter (Kawaguchi and Satake, 1994;Daly, 1998;Atkinson et al, 2004;Smetacek and Nicol, 2005;Quetin and Ross, 2009) and is associated with the ice at all stages of its life cycle (Flores et al, 2012 and references therein). Thus, changes in the timing and/or extent of sea ice cover are likely to have major implications for the Antarctic food web (see below, Quetin and Ross, 2009).…”

Section: Seasonal Sea Ice Zonementioning

confidence: 99%

“…For example, the phenology of the Antarctic krill, Euphausia superba, a keystone organism in SO food webs, is integrally liked to sea ice and seasonality, largely due to its being a refuge and source of algal nutrition over winter (Kawaguchi and Satake, 1994;Daly, 1998;Atkinson et al, 2004;Smetacek and Nicol, 2005;Quetin and Ross, 2009) and is associated with the ice at all stages of its life cycle (Flores et al, 2012 and references therein). Thus, changes in the timing and/or extent of sea ice cover are likely to have major implications for the Antarctic food web (see below, Quetin and Ross, 2009).…”

Section: Seasonal Sea Ice Zonementioning

confidence: 99%

Southern Ocean Phytoplankton in a Changing Climate

2017

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Phytoplankton are the base of the Antarctic food web, sustain the wealth and diversity of life for which Antarctica is renowned, and play a critical role in biogeochemical cycles that mediate global climate. Over the vast expanse of the Southern Ocean (SO), the climate is variously predicted to experience increased warming, strengthening wind, acidification, shallowing mixed layer depths, increased light (and UV), changes in upwelling and nutrient replenishment, declining sea ice, reduced salinity, and the southward migration of ocean fronts. These changes are expected to alter the structure and function of phytoplankton communities in the SO. The diverse environments contained within the vast expanse of the SO will be impacted differently by climate change; causing the identity and the magnitude of environmental factors driving biotic change to vary within and among bioregions. Predicting the net effect of multiple climate-induced stressors over a range of environments is complex. Yet understanding the response of SO phytoplankton to climate change is vital if we are to predict the future state/s of the ecosystem, estimate the impacts on fisheries and endangered species, and accurately predict the effects of physical and biotic change in the SO on global climate. This review looks at the major environmental factors that define the structure and function of phytoplankton communities in the SO, examines the forecast changes in the SO environment, predicts the likely effect of these changes on phytoplankton, and considers the ramifications for trophodynamics and feedbacks to global climate change. Predictions strongly suggest that all regions of the SO will experience changes in phytoplankton productivity and community composition with climate change. The nature, and even the sign, of these changes varies within and among regions and will depend upon the magnitude and sequence in which these environmental changes are imposed. It is likely that predicted changes to phytoplankton communities will affect SO biogeochemistry, carbon export, and nutrition for higher trophic levels.

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“…The latter the timing of annual sea ice formation, the lower the food availability to krill, and the lower the growth rates and predicted survival rates of juvenile krill in particular (Quetin & Ross 2009). Affects physiology and carbonate deposition by calcifying organisms such as krill (Bednarsek et al 2012;Byrne 2011;Constable et al 2014;Ingels et al 2012;Kawaguchi et al 2013;Kawaguchi et al 2011;Moy et al 2009).…”

Section: Increased Uv and Irradiancementioning

confidence: 99%

Managing direct and indirect threats to marine ecosystems to balance multiple objectives

Tulloch¹

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Human activities affecting the environment are intensifying. In marine ecosystems, direct stressors of overfishing and habitat destruction have led to biodiversity declines, prompting calls for conservation action and more sustainable resource management. Managing stressors becomes more challenging when stressors interact, or are indirect, whereby the source of the threatening activity is displaced from impacts, such as the localised effects of global warming, or runoff from land-use change degrading coral reefs. Effective management requires improved understanding of ecosystem responses to multiple stressors and consideration of interactions between stressors and species.Opposing objectives and outcomes of marine conservation (i.e. reducing stressors) versus resource management (often increasing stressors) compromise effective decision-making. Approaches are needed that include ecological and socio-economic information to promote long-term sustainability of extractive uses, protect functioning ecosystems, and conserve biodiversity. The choice of tool used to inform ecosystem management is typically constrained by management goals and available resources -spatial planning is typically used for conservation, whereas resource management relies more on population modelling.The goal of this thesis is to harness spatial and population modelling techniques to combine resource management with biodiversity conservation and link direct and indirect stressors to marine biodiversity persistence. Chapter 1 provides the context for the thesis, where I explore these themes and outline differences in decision-making for conservation versus extraction. In Chapter 2, I explore how agencies have managed stressors to date, and show that a decision-theoretic approach known as "structured decision-making" (SDM) is a more logical and effective way of managing stressors than traditional approaches that map threats. SDM requires clear objectives, canvassing of alternative management options, and linking outcomes for biodiversity to the effectiveness of each management option. SDM ensures that conservation actions occur where they are the most cost-efficient or effective. I apply recommendations from Chapter 2 in two case studies for managing multiple stressors to marine ecosystems: 1) spatial planning for oil palm agriculture and coral reef fisheries in Papua New Guinea (Chapters 3 and 4), and 2) managing whale species affected by harvesting, climate change and krill population dynamics in the Southern Hemisphere (Chapters 5 and 6).In Chapter 3 I combine ecosystem models and threat maps with spatial conservation planning to predict responses of coral and seagrass ecosystems to changing land uses. My novel framework identifies high priority areas for marine reserves whilst accounting for indirect impacts of land use change such as oil palm development and uncertainty in future stressor intensities. I demonstrate ii how we can reduce adverse impacts of oil palm expansion and make more effective whole-ofsystem decisions for coasta...

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Life Under Antarctic Pack Ice: A Krill Perspective

Cited by 17 publications

References 73 publications

The overwintering of Antarctic krill, Euphausia superba, from an ecophysiological perspective

The overwintering of Antarctic krill, Euphausia superba, from an ecophysiological perspective

Southern Ocean Phytoplankton in a Changing Climate

Managing direct and indirect threats to marine ecosystems to balance multiple objectives

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