Zooplankton

Zooplankton are tiny drifting animals that play a critical role in aquatic food webs, linking phytoplankton to larger marine species.

01

Species Role

Zooplankton hold a key position in aquatic food webs. They feed on phytoplankton, bacteria, and other zooplankton, and are a major food source for fish, seabirds, and baleen whales. The zooplankton are a diverse group of animals, some of which form calcium carbonate structures (foraminifera, pteropods, and heteropods). Thus, the zooplankton response to acidification is variable.

Acidification Impacts on Zooplankton

Direct responses to acidification can include reduced calcification rates and disturbance to acid-base (metabolic) physiology, which can affect other bodily functions. Pteropods, with thin snail-like shells, have been shown to be highly sensitive to decreases in ocean pH causing shell dissolution.

Indirect effects, while more difficult to measure, include changes to the abundance, composition, and quality of their food source (phytoplankton), which can significantly impact zooplankton metabolic function.

Risks for Zooplankton Life Stages

Adult non-calcifying zooplankton are thought to be more tolerant of acidification, but negative effects tend to be amplified in their younger life stages. This has been demonstrated with reduced survival and hatching success and irregular larval development at early developmental stages in several zooplankton groups, including copepods and krill. Krill are an important food source for many marine mammals.

Both direct and indirect responses to acidification can impact zooplankton development, growth, reproduction, and overall population.

Predicting Zooplankton Responses to Acidification

Due to variable responses of different species to acidification and differential effects to various zooplankton life stages, it is difficult to predict how natural zooplankton communities will respond to acidification and how those changes will reverberate through food webs.

Furthermore, other stressors including changes in water temperature, food source, and levels of dissolved oxygen can also affect zooplankton abundance and community composition and therefore need to be considered simultaneously with acidification.

References

Cooper, HL, Potts, DC, Paytan, A. 2016. Metabolic responses of the North Pacific krill, Euphausia pacifica, to short- and long-term pCO2 exposure. Marine Biology 163:207. doi: 10.1007/s00227-016-2982.

Cooper, HL, Potts, DC, Paytan, A. 2017. Effects of elevated pCO2 on the survival, growth, and moulting of the Pacific krill species Euphausia pacifica. ICES Journal of Marine Science 74: 1005-1012. doi: 10.1093/icesjms/fsw021.

Cripps, G, Lindeque, P, Flynn, KJ. 2014. Have we been underestimating the effects of ocean acidification in zooplankton? Global Change Biology 20: 3377-3385. doi: 10.1111/gcb.12582.

Cripps, G, Flynn, KJ, Lindeque, PK, Dam, HG. 2016. Ocean Acidification Affects the Phyto-Zoo Plankton Trophic Transfer Efficiency, PLoS ONE 11(4): e0151739.

Garzke, J, Hansen, T, Ismar, SMH, Sommer, U, Ross, P. 2016. Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content, PLoS ONE 11(5): e0155952.

Kawaguchi, S, Kurihara, H, King, R, Hale, L, Berli, T, and others. 2010. Will krill fare well under Southern Ocean acidification? Biology Letters 7: 288-291. doi:10.1098/rsbl.2010.0777.

Kawaguchi, S, Ishida, A, King, R, Raymond, B, Waller, N, and others. 2013. Risk maps for Antarctic krill under projected Southern Ocean acidification. Nature Climate Change 3: 843–847. doi:10.1038/nclimate1937.

Kurihara, H. 2008. Effects of CO2-driven ocean acidification on the early developmental stages of invertebrates. Marine Ecology Progress Series 373: 275-284. doi:10.3354/meps07802.

Maas, AE, Elder, LE, Dierssen, HM, Seibel, BA. 2011. The metabolic response of Antarctic pteropods (Mollusca: Gastropoda) to regional productivity: implications for biogeochemical cycles. Marine Ecology Progress Series 441: 129-131. doi: 10.3354/meps09358.

Rossoll, D, Bermúdez, R, Hauss, H, Schulz, KG, Riebesell, U, and others. 2012. Ocean Acidification-Induced Food Quality Deterioration Constrains Trophic Transfer. PLoS ONE 7(4): e34737.

Saba, GK, Schofield, O, Torres, JJ, Ombres, EH, Steinberg, DK. 2012. Increased feeding and nutrient excretion of adult Antarctic krill, Euphausia superba, exposed to enhanced carbon dioxide (CO2). PLoS ONE 7: e0052224.

Seibel, BA, Maas, AE, Dierssen, HM. 2012. Energetic plasticity underlies a variable response to ocean acidification in the pteropod, Limacina helicina antarctica. PLoS ONE 7(4): e30464.

Zhang, D, Li, S, Wang, G, Guo, D. 2011. Impacts of CO2-driven seawater acidification on survival, egg production rate and hatching success of four marine copepods. Acta Oceanologica Sinica 30: 86-94. doi:10.1007/s13131-011-0165-9.

Get Involved

If you are interested in learning more about MACAN and the work we do, please sign up for our monthly newsletter. You can also read our 2024 to 2028 Work Plan.

View Macan's 2024-2028 Work plan

Site By3Lane Marketing