Zooplankton

Ecosystems

Ecosystems are highly complex webs of species that mix in space and time, creating intricate relationships that can be difficult or complex to study.

Ecosystem Impacts

An ecosystem comprises a community of living things, their non-living environment, and the interactions that link species to one another and to their surroundings. Acidification, among other stressors, such as increasing ocean temperatures, harmful algal bloom occurrences, and sea level rise, will affect individual species and the ecosystems they inhabit in diverse ways. Understanding the influence of acidification on entire ecosystems is difficult due to the complexity of the water chemistry, co-occurring biological processes, and the complexity of marine ecosystems themselves.

Species Interactions under Acidified Conditions

When acidification impacts one species, whether that’s in a positive or negative way, it can cause a ripple effect that alters ecosystem dynamics in general.

For example:

Changes in species abundance or behavior can alter food webs and predator/prey dynamics.
Loss of habitat-forming species, like corals, can leave marine life without shelter or nursery habitat.
Some species can alter their abiotic environment, to the benefit (or detriment) of other species. For example, faster growth by seagrasses due to elevated CO₂ may theoretically help to locally increase pH, which can benefit the species that live in the grasses.

Environmental Factors Change the pH

The severity of ocean acidification, and the impact it has on species, varies based on local and regional environmental conditions. Because of this, organisms living in vastly different ecosystems, like estuaries versus the open ocean, experience different pH “weather”. In contrast to the open ocean, the coastal ocean regularly experiences large fluctuations in pH on timescales ranging from hours (tides) to years (changing climate conditions).

pH "weather" events are influenced by:

Precipitation
Nutrient runoff & eutrophication due to storm water runoff and seasonal patterns
Day-night cycles of biological activity (respiration at night produces CO₂ while photosynthesis during the day consumes CO₂)
Oceanic events like upwelling that could be caused by changing wind direction and storms

Co-stressors in the Marine Environment

Oftentimes, acidification is not the only stressor marine species are facing. When considering temperatures, eutrophication, oxygen availability, and more, the ultimate impact of acidification on marine life can change; sometimes the abiotic environment exacerbates acidification effects or in other cases buffers against them. Careful and extensive experiments are necessary to understand how low pH interacts with other environmental variables for different species.

Decoding Acidification Effects on Ecosystems

Many acidification experiments to date have been performed with only a single species in isolation. However, ecosystems are a complex network of species that interact via food webs, symbiotic relationships, and a myriad of other mechanisms. More and more, experts are working on understanding the intricacies of ecosystem response to acidification.

References

Baumann, H. (2019). Experimental assessments of marine species sensitivities to ocean acidification and co-stressors: How far have we come? Canadian Journal of Zoology, 97(5), 399–408. https://doi.org/10.1139/cjz-2018-0198

Cai, W.-J., Feely, R. A., Testa, J. M., Li, M., Evans, W., Alin, S. R., Xu, Y.-Y., Pelletier, G., Ahmed, A., Greeley, D. J., Newton, J. A., & Bednaršek, N. (2021). Natural and Anthropogenic Drivers of Acidification in Large Estuaries. Annual Review of Marine Science, 13(1), 23–55. https://doi.org/10.1146/annurev-marine-010419-011004

Doney, S. C., Busch, D. S., Cooley, S. R., & Kroeker, K. J. (2020). The Impacts of Ocean Acidification on Marine Ecosystems and Reliant Human Communities. Annual Review of Environment and Resources, 45(1), 83–112. https://doi.org/10.1146/annurev-environ-012320-083019

Glaspie, C. N., Longmire, K., & Seitz, R. D. (2017). Acidification alters predator-prey interactions of blue crab Callinectes sapidus and soft-shell clam Mya arenaria. Journal of Experimental Marine Biology and Ecology, 489, 58–65. https://doi.org/10.1016/j.jembe.2016.11.010

Guinotte, J. M., & Fabry, V. J. (2008). Ocean Acidification and Its Potential Effects on Marine Ecosystems. Annals of the New York Academy of Sciences, 1134(1), 320–342. https://doi.org/10.1196/annals.1439.013

Hoegh-Guldberg, O., Poloczanska, E. S., Skirving, W., & Dove, S. (2017). Coral Reef Ecosystems under Climate Change and Ocean Acidification. Frontiers in Marine Science, 4, 158. https://doi.org/10.3389/fmars.2017.00158

Jin, P., Hutchins, D. A., & Gao, K. (2020). The Impacts of Ocean Acidification on Marine Food Quality and Its Potential Food Chain Consequences. Frontiers in Marine Science, 7, 543979. https://doi.org/10.3389/fmars.2020.543979

Marshall, K. N., Kaplan, I. C., Hodgson, E. E., Hermann, A., Busch, D. S., McElhany, P., Essington, T. E., Harvey, C. J., & Fulton, E. A. (2017). Risks of ocean acidification in the California Current food web and fisheries: Ecosystem model projections. Global Change Biology, 23(4), 1525–1539. https://doi.org/10.1111/gcb.13594

Ricart, A. M., Ward, M., Hill, T. M., Sanford, E., Kroeker, K. J., Takeshita, Y., Merolla, S., Shukla, P., Ninokawa, A. T., Elsmore, K., & Gaylord, B. (2021). Coast‐wide evidence of low pH amelioration by seagrass ecosystems. Global Change Biology, 27(11), 2580–2591. https://doi.org/10.1111/gcb.15594

Saba, G. K., Goldsmith, K. A., Cooley, S. R., Grosse, D., Meseck, S. L., Miller, A. W., Phelan, B., Poach, M., Rheault, R., St.Laurent, K., Testa, J. M., Weis, J. S., & Zimmerman, R. (2019). Recommended priorities for research on ecological impacts of ocean and coastal acidification in the U.S. Mid-Atlantic. Estuarine, Coastal and Shelf Science, 225, 106188. https://doi.org/10.1016/j.ecss.2019.04.022

Smithsonian Environmental Research Center, Breitberg, D., Salisbury, J., Bernhard, J., Cai, W.-J., Dupont, S., Doney, S., Kroeker, K., Levin, L., Long, W. C., Milke, L., Miller, S., Phelan, B., Passow, U., Seibel, B., Todgham, A., & Tarrant, A. (2015). And on Top of All That… Coping with Ocean Acidification in the Midst of Many Stressors. Oceanography, 25(2), 48–61. https://doi.org/10.5670/oceanog.2015.31

Stevens, A., & Gobler, C. (2018). Interactive effects of acidification, hypoxia, and thermal stress on growth, respiration, and survival of four North Atlantic bivalves. Marine Ecology Progress Series, 604, 143–161. https://doi.org/10.3354/meps12725

Waldbusser, G. G., & Salisbury, J. E. (2014). Ocean Acidification in the Coastal Zone from an Organism’s Perspective: Multiple System Parameters, Frequency Domains, and Habitats. Annual Review of Marine Science, 6(1), 221–247. https://doi.org/10.1146/annurev-marine-121211-172238

Ecosystems

References

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