MEPS 555:65-78 (2016)  -  DOI: https://doi.org/10.3354/meps11839

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

Anna K. McLaskey1,*, Julie E. Keister1, Paul McElhany2, M. Brady Olson3, D. Shallin Busch4, Michael Maher2, Amanda K. Winans

1School of Oceanography, University of Washington, Seattle, Washington 98105, USA
2Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington 98112, USA
3Shannon Point Marine Center, Western Washington University, Anacortes, Washington 98221, USA
4Ocean Acidification Program and Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, Washington 98112, USA
*Corresponding author:

ABSTRACT:  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.


KEY WORDS: Ocean acidification · Zooplankton · Euphausiids · pH · Survival · Exposure


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Cite this article as: McLaskey AK, Keister JE, McElhany P, Olson MB, Busch DS, Maher M, Winans AK (2016) Development of Euphausia pacifica (krill) larvae is impaired under pCO2 levels currently observed in the Northeast Pacific. Mar Ecol Prog Ser 555:65-78. https://doi.org/10.3354/meps11839

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