Coral reefs are sources of incredibly high marine biodiversity and importance to marine ecosystems. Along with providing habitat for multitudes of species, they also act as a buffer to protect shoreline from strong waves, and are sources of marine nitrogen and carbon fixation (NOAA, 2013). Many, namely anthropogenic, factors are causing great harm and destruction to these important marine ecosystems; one factor being ocean temperature. Coral is a marine invertebrate under the phylum Cnidaria, and by connecting polyps with calcium carbonate, are able to form these stoney, intricate shelves. Cnidaria, are able to survive lower temperatures by going into a dormant state, but have a low threshold for warmer temperatures. As the temperature of the water increases, the coral is put under greater stress, resulting in the algae bonded to the coral through a symbiotic relationship to release bonds, removing the coral's food source and thus turning white (McClanahan et. al, 2007). Following the bleaching, the coral becomes highly susceptible to disease and no longer is able to support the species that survive in the intricate coral reef system.
A solution to this phenomenon is vital for the conservation of marine ecosystems. Coral acts as a buffer for storms, provide habitat and food for fish, and have intrinsic cultural and economic value. There has been a strong social media movement in recent years, with many people from different backgrounds expressing their concern over coral. Our research seeks to look at the potential solution of coral propagation with more resilient varieties that could rebuild the ecosystem. Additionally, we hope to raise further awareness for marine issues and inform policymakers of the urgency and potential solutions and measures that could be taken to mitigate coral bleaching.
A solution to this phenomenon is vital for the conservation of marine ecosystems. Coral acts as a buffer for storms, provide habitat and food for fish, and have intrinsic cultural and economic value. There has been a strong social media movement in recent years, with many people from different backgrounds expressing their concern over coral. Our research seeks to look at the potential solution of coral propagation with more resilient varieties that could rebuild the ecosystem. Additionally, we hope to raise further awareness for marine issues and inform policymakers of the urgency and potential solutions and measures that could be taken to mitigate coral bleaching.
The Mascarene Islands Ecoregion consists of a group of islands connected by a series of coral reef shelves and lagoons. The ocean temperatures remain relatively stable throughout the year, and the coral had managed to escape bleaching until a mass bleaching event in 2002 around the island of Rodriguez (Hardman et al., 2010). Since then, bleached hectares have increased, as coral is more susceptible, as well anthropogenic disturbances such as fishing, tourism, and urban development have increased sedimentation and destruction of shelves (Jouval et al., 2019).
Map: https://www.researchgate.net/profile/Vikash_Tatayah/publication/327848071/figure/fig1/AS:674476052185092@1537819030652/Location-of-Mascarene-Islands.png
Morikawa and Polumbi (2019), observed the propagation and establishment success rates of four different species of coral in the American Samoa, off the coast of Australia, an area heavily hit by bleaching as well. They utilized four species of coral: Acropora hyacinthus, Acropora gemmifera, Pocillopora damicornis, and Porites cylindrica, which are common varieties of coral that have shown to be relatively resilient to rising water temperatures (Morikawa & Polumbi, 2019). These species are common around the world, and so following surveys done within our study site, we chose to use the same species as they are also native to this area of the Indian Ocean. Morikawa and Polumbi studied mainly the changes in the symbiont relationships and the changes that occur over time, however we chose to focus just on the initial viability and growth of transplanted coral fragments.
Our study looks at the plausibility of using nursery coral transplants of heat tolerant species to reestablish areas where bleaching has impacted or is at risk of impacting the area in the near future. This was done by a plot system of planted and anchored coral propagules of all four species, and were raised in-situ to account for natural conditions, on a site between La Reunion and Mauritus islands. Weight was measured at the end of a 2 year growth period, and data was separated into high and moderate temperature levels. We predict that the weight of the coral will be positively influenced by lower sea temperatures, as well as by the species of coral. We hope to find that all four species tested will grow well, as to continue and encourage the diversity that coral reefs are known for.
Our study looks at the plausibility of using nursery coral transplants of heat tolerant species to reestablish areas where bleaching has impacted or is at risk of impacting the area in the near future. This was done by a plot system of planted and anchored coral propagules of all four species, and were raised in-situ to account for natural conditions, on a site between La Reunion and Mauritus islands. Weight was measured at the end of a 2 year growth period, and data was separated into high and moderate temperature levels. We predict that the weight of the coral will be positively influenced by lower sea temperatures, as well as by the species of coral. We hope to find that all four species tested will grow well, as to continue and encourage the diversity that coral reefs are known for.
References
Hardman, E. R., Sabrina Meunier, M., Turner, J. R., Lynch, T. L., Taylor, M., & Klaus, R. (2004). The extent of coral bleaching in Rodrigues, 2002. Journal of Natural History, 38(23-24), 3077-3089.
Jouval, F., Latreille, A. C., Bureau, S., Adjeroud, M., & Penin, L. (2019). Multiscale variability in coral recruitment in the Mascarene Islands: From centimetric to geographical scale. PloS one, 14(3), e0214163.
Mcclanahan, T. R., Ateweberhan, M., Muhando, C. A., Maina, J., & Mohammed, M. S. (2007). Effects Of Climate And Seawater Temperature Variation On Coral Bleaching And Mortality. Ecological Monographs, 77(4), 503-525. doi:10.1890/06-1182.1
Morikawa, M. K., & Palumbi, S. R. (2019). Using naturally occurring climate resilient corals to construct bleaching-resistant nurseries. Proceedings of the National Academy of Sciences, 116(21), 10586-10591.
US Department of Commerce, N. (2013, June 01). The Importance of Coral Reefs - Corals: NOAA's National Ocean Service Education. Retrieved October 27, 2020, from https://oceanservice.noaa.gov/education/tutorial_corals/coral07_importance.html
Hardman, E. R., Sabrina Meunier, M., Turner, J. R., Lynch, T. L., Taylor, M., & Klaus, R. (2004). The extent of coral bleaching in Rodrigues, 2002. Journal of Natural History, 38(23-24), 3077-3089.
Jouval, F., Latreille, A. C., Bureau, S., Adjeroud, M., & Penin, L. (2019). Multiscale variability in coral recruitment in the Mascarene Islands: From centimetric to geographical scale. PloS one, 14(3), e0214163.
Mcclanahan, T. R., Ateweberhan, M., Muhando, C. A., Maina, J., & Mohammed, M. S. (2007). Effects Of Climate And Seawater Temperature Variation On Coral Bleaching And Mortality. Ecological Monographs, 77(4), 503-525. doi:10.1890/06-1182.1
Morikawa, M. K., & Palumbi, S. R. (2019). Using naturally occurring climate resilient corals to construct bleaching-resistant nurseries. Proceedings of the National Academy of Sciences, 116(21), 10586-10591.
US Department of Commerce, N. (2013, June 01). The Importance of Coral Reefs - Corals: NOAA's National Ocean Service Education. Retrieved October 27, 2020, from https://oceanservice.noaa.gov/education/tutorial_corals/coral07_importance.html