Increased Feeding and Nutrient Excretion of Adult Antarctic Krill, Euphausia superba, Exposed to Enhanced Carbon Dioxide (CO2)

Saba, Grace; Schofield, Oscar; Torres, Joseph J.; Ombres, Erica H.; Steinberg, Deborah K.

doi:10.1371/journal.pone.0052224

Cited by 57 publications

(41 citation statements)

References 109 publications

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“…Besides this krill decline, differences in the stoichiometry of excretion products are potentially important in determining the relative degree of nutrient limitation and thus algal species composition (Vanni 2002). It has been described that environmental changes can affect the ratios at which the different nutrients are recycled by krill, in example, predicting increased NH 4 + , DOC, and PO 4 + release rates in a high CO 2 scenario (Saba et al 2012).…”

Section: Discussionmentioning

confidence: 99%

Zooplankton excretion metabolites stimulate Southern Ocean phytoplankton growth

Coello-Camba

Llabrés²,

Duarte

et al. 2017

Polar Biol

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Section: Discussionmentioning

confidence: 99%

Zooplankton excretion metabolites stimulate Southern Ocean phytoplankton growth

Coello-Camba

Llabrés²,

Duarte

et al. 2017

Polar Biol

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“…Experiments have shown that Euphausia superba, a keystone species in Antarctic ecosystems, has reduced hatching at 1250 µatm pCO 2 (pH 7.50) compared to 380 µatm and complete hatching failure at 2000 µatm pCO 2 (pH 7.36−7.40); however, at 3 d post hatch (dph) larval swimming activity is not affected at 1000 µatm pCO 2 (Kawaguchi et al 2011(Kawaguchi et al , 2013. Even at moderate levels of 672 µatm pCO 2 (pH 7.84), adult E. superba increase feeding and nutrient excretion rates, which may indicate shifts in metabolism associated with acid−base regulation (Saba et al 2012). Sub-adults of the north Atlantic krill Nyctiphanes couchii have reduced survival at pCO 2 concentrations between 1100 and 1700 µatm pCO 2 (pH 7.63 and 7.47), but other life stages have not been tested (Sperfeld et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Development of Euphausia pacifica (krill) larvae is impaired under pCO2 levels currently observed in the Northeast Pacific

McLaskey¹,

Keister²,

McElhany³

et al. 2016

Mar. Ecol. Prog. Ser.

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Despite the critical importance of euphausiids in marine food webs, little ocean acidification (OA) research has focused on them. Euphausia pacifica is a dominant and trophically important species of euphausiid throughout the North Pacific and the California Current Ecosystem, where low pH conditions are occurring in advance of those in the global ocean. We assessed the impact of reduced pH on the hatching and larval development of E. pacifica in the laboratory and characterized the pH to which E. pacifica eggs and larvae are currently exposed in Puget Sound, Washington (USA), a large estuary connected to the California Current. In 2 independent sets of laboratory experiments that lasted 6 to 22 d and which involved broods from 110 different females, we found that hatching is robust to a wide range of pH levels, but larval development and survival are reduced at pH levels that are currently observed within their habitat. Survival from 3 d post hatch to the calyptopis 2 stage was reduced by an average of 20% at pH 7.69 compared to pH 7.96. Even though this population experiences a range of pH conditions on seasonal and daily timescales, it may be living near the limits of its pH tolerance. Continued OA may push these organisms past their threshold, which could have cascading negative consequences for higher trophic levels.

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“…Adult behavioural changes, avoiding approximately 3.1d (Buchholz 2003). Krill IMP significantly lower at elevated temperature treatments (Brown et al 2010b;Saba et al 2012). production could deprive krill of sufficient food to support their energy requirements, and therefore retard krill gonadal development and spawning (Loeb et al 1997).…”

Section: Observed Impactmentioning

confidence: 93%

“…Ingestion rates of krill 3.5 times higher than krill ingestion rates at ambient, present day CO 2 concentrations (Saba et al 2012). Under the RCP 8.5 scenario most of krill habitat will suffer at least 20% lower hatching success by 2100, with reductions of up to 60-70% in the Weddell Sea (Sth Atlantic) = threshold of no recruitment at 2000 ppm CO 2 .…”

Section: Observed Impactmentioning

confidence: 97%

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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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Increased Feeding and Nutrient Excretion of Adult Antarctic Krill, Euphausia superba, Exposed to Enhanced Carbon Dioxide (CO2)

Cited by 57 publications

References 109 publications

Zooplankton excretion metabolites stimulate Southern Ocean phytoplankton growth

Zooplankton excretion metabolites stimulate Southern Ocean phytoplankton growth

Development of Euphausia pacifica (krill) larvae is impaired under pCO2 levels currently observed in the Northeast Pacific

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

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