The Impact Of Climate Change On Marine Biology And Ecology

By Dr. Luis Vaschetto, Ph.D.Reviewed by Lily Ramsey, LLM

Climate change can be defined as a long-term shift in Earth's average weather conditions. It has been associated with human activities, such as burning fossil fuels, which release greenhouse gases into the atmosphere. These gases can trap heat, causing global temperatures to rise.

Marine biology and ecology study the interactions between marine organisms and their environments. Healthy oceans are crucial for supporting a wide range of biodiversity, providing food resources, and regulating global climate systems.

Warmer waters can stress marine organisms, leading to changes in behavior, reproduction, and survival rates. Moreover, the oceans absorb a significant portion of the carbon dioxide emitted into the atmosphere, ultimately leading to a chemical reaction that increases the water's acidity.

​​​​​​​Image Credit: metamorworks/Shutterstock.com

Warming Oceans and Its Effects on Marine Life

Increasing ocean temperatures have far-reaching consequences for marine species, leading to shifts in distribution, migration patterns, and altered breeding cycles. As temperatures rise, species may be forced to migrate to cooler waters, leading to range contractions and potential habitat loss¹.

Moreover, many marine species undertake seasonal migrations. Climate change can disrupt these patterns, affecting food availability and reproductive success².

Coral reefs are particularly vulnerable to rising ocean temperatures. When water temperatures exceed a certain threshold, corals expel the symbiotic algae that give them color and provide nutrients. This process, known as coral bleaching, can lead to coral death and the loss of valuable marine habitats^3,4.

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Ocean Acidification and Its Consequences

Ocean acidification may be a serious threat to shell-forming organisms, although ocean acidification impacts on calcifiers are less deleterious than initially thought⁵.

Corals, for example, rely on calcium carbonate to construct their skeletons. As the ocean becomes more acidic, it becomes harder for them to extract the necessary minerals. This can lead to weakened coral structures and increased susceptibility to disease. Additionally, changes in these organisms can negatively impact human industries like fishing and aquaculture, as they rely on healthy marine ecosystems for their livelihoods.

Sea Level Rise and Habitat Loss

As sea levels rise, coastal ecosystems, including mangroves, estuaries, and salt marshes, face inundation, erosion, and saltwater intrusion. Mangroves, for example, are adapted to live in brackish water, but as sea levels rise, saltwater intrusion can displace freshwater, affecting their survival.

Additionally, rising sea levels can increase coastal erosion, threatening infrastructure and coastal communities.

Impact on Marine Biodiversity and Ecosystems

Climate change is driving a significant decline in marine biodiversity. For example, temperature changes can alter the distribution and abundance of prey species, affecting predators that rely on them⁶. This can lead to cascading effects throughout the food web.

Keystone species, which play a critical role in maintaining ecosystem balance, are particularly vulnerable to climate change. Coral reefs, for instance, are highly sensitive to temperature increases and ocean acidification. The decline of coral reefs can have serious consequences for marine life, as they provide habitat and food for countless species⁷.

Kelp forests, another important ecosystem, are also threatened by climate change. Warmer waters and changes in nutrient availability can lead to the decline of kelp, impacting the species that rely on it for food and shelter.

Research and Conservation Efforts

Scientists are actively researching the impacts of climate change on marine ecosystems to develop effective mitigation strategies. This includes studying the effects of rising temperatures, ocean acidification, and sea level rise on marine species and habitats. Additionally, they are investigating the potential of natural solutions like seagrass meadows to help mitigate climate change by sequestering carbon. 

Innovative conservation efforts are being implemented to protect marine ecosystems from the effects of climate change. Marine protected areas (MPAs) are designated regions where human activities are restricted or prohibited to conserve biodiversity^8,9.

These areas can provide safe havens for marine species and help them adapt to changing conditions. Coral restoration projects are also being undertaken to restore damaged coral reefs.

Scientists are developing techniques to propagate and transplant coral fragments, helping to rebuild these vital ecosystems. Carbon sequestration techniques, such as seaweed farming, are gaining attention as potential solutions to climate change¹⁰.

Seaweed can absorb carbon dioxide from the atmosphere and help reduce greenhouse gas emissions. Additionally, seaweed farming can provide economic benefits to coastal communities and support sustainable fisheries. 

International agreements, such as the Paris Agreement, play a crucial role in addressing climate change and promoting ocean health. The Paris Agreement aims to limit global warming to well below 2 degrees Celsius, with a three-lever strategy including carbon neutrality, superpollutant, and carbon extraction/sequestration¹¹.

By reducing greenhouse gas emissions, countries can help mitigate the impacts of climate change on marine ecosystems. Additionally, the agreement encourages international cooperation and the sharing of knowledge and technology to address climate-related challenges.

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Future Projections and Long-Term Impacts

If climate change continues, marine ecosystems face a bleak future. Scientific projections indicate a significant decline in marine biodiversity, with the potential for mass extinctions. Coral reefs, which support a vast array of marine life, are particularly vulnerable to these stressors.

The loss of coral reefs can have cascading effects on entire ecosystems, leading to declines in fish populations and disruptions in whole food webs. In addition to mass extinctions, climate change could lead to irreversible changes to ocean systems. Rising sea levels could also lead to the loss of coastal habitats, such as mangroves and salt marshes, which provide important ecosystem services.

Conclusion

Climate change poses a significant threat to marine biology and ecology. Rising temperatures, ocean acidification, and sea level rise are disrupting marine ecosystems, leading to declines in biodiversity, changes in species distributions, and alterations in food chain dynamics.

These impacts have far-reaching consequences for human life, as oceans provide food, regulate climate, and support coastal communities. Continued research, conservation efforts, and global cooperation are crucial to addressing the climate crisis and safeguarding the health of the world’s oceans. By working together, we can mitigate the effects of climate change and ensure a healthy future for our oceans.

References

1. Gallagher, K., & Albano, P. (2023). Range contractions, fragmentation, species extirpations, and extinctions of commercially valuable molluscs in the Mediterranean Sea—a climate warming hotspot. ICES Journal of Marine Science. https://doi.org/10.1093/icesjms/fsad065.
2. Patterson, A., Gilchrist, H., Gaston, A., & Elliott, K. (2021). Northwest range shifts and shorter wintering period of an Arctic seabird in response to four decades of changing ocean climate. Marine Ecology Progress Series. https://doi.org/10.3354/meps13890.
3. Brown, B. (1997). Coral bleaching: causes and consequences. Coral Reefs, 16, S129-S138. https://doi.org/10.1007/s003380050249.
4. Virgen-Urcelay, A., & Donner, S. (2023). Increase in the extent of mass coral bleaching over the past half-century, based on an updated global database. PLOS ONE, 18. https://doi.org/10.1371/journal.pone.0281719.
5. Leung, J., Zhang, S., & Connell, S. (2022). Is Ocean Acidification Really a Threat to Marine Calcifiers? A Systematic Review and Meta-Analysis of 980+ Studies Spanning Two Decades. Small, e2107407. https://doi.org/10.1002/smll.202107407.
6. Florko, K., Tai, T., Cheung, W., Ferguson, S., Sumaila, U., Yurkowski, D., & Auger‐Méthé, M. (2021). Predicting how climate change threatens the prey base of Arctic marine predators. Ecology letters. https://doi.org/10.1111/ele.13866.
7. Alves, C., Aronson, R., Bood, N., Castillo, K., Cox, C., Fieseler, C., Locklear, Z., McField, M., Mudge, L., Umbanhowar, J., Valdivia, A., & Bruno, J. (2021). Twenty years of change in benthic communities across the Belizean Barrier Reef. PLoS ONE, 17. https://doi.org/10.1371/journal.pone.0249155.
8. Cintio, A., Niccolini, F., Scipioni, S., & Bulleri, F. (2023). Avoiding “Paper Parks”: A Global Literature Review on Socioeconomic Factors Underpinning the Effectiveness of Marine Protected Areas. Sustainability. https://doi.org/10.3390/su15054464.
9. Humphreys, J., & Herbert, R. (2018). Marine protected areas: Science, policy & management. Estuarine, Coastal and Shelf Science. https://doi.org/10.1016/J.ECSS.2018.10.014.
10. Gao, G., Gao, L., Jiang, M., Jian, A., & He, L. (2021). The potential of seaweed cultivation to achieve carbon neutrality and mitigate deoxygenation and eutrophication. Environmental Research Letters, 17. https://doi.org/10.1088/1748-9326/ac3fd9.
11. Xu, Y., & Ramanathan, V. (2017). Well below 2 °C: Mitigation strategies for avoiding dangerous to catastrophic climate changes. Proceedings of the National Academy of Sciences, 114, 10315 - 10323. https://doi.org/10.1073/pnas.1618481114.