How will climate change affect seagrass ecosystems?

Climate change is affecting ecosystems around the world, including seagrasses. The combustion of fossil fuels since the Industrial Revolution has increased the atmospheric carbon dioxide (CO2) concentration, increasing the greenhouse effect by trapping more solar heat near the earth’s surface. Seagrasses and other marine creatures residing at the edge of their distributional range are vulnerable to the effects of rising ocean temperatures. Warmer water temperatures can cause changes in physiology (i.e., metabolic rates), behavior (i.e., increased grazing effort), resulting in altered population dynamics, susceptibility to disease, food and oxygen requirements and range shifts, all of which can alter biodiversity and ecosystem function. For example, “tropicalization” occurs as tropical species extend their range into temperate regions, altering foodwebs, introducing new diseases and parasites and potentially destabilizing temperate species populations. With the increase in atmospheric carbon dioxide, The oceans continue to uptake more CO2 which lowers pH (i.e., more acidic) in a process known as ocean acidification (OA). OA hinders the calcification processes of important micro- and macroalgae communities as well as corals, mollusks and some crustaceans – particularly during early life history stages. Although negatively influenced by warming coastal waters, rising sea levels, and changing precipitation patterns, seagrasses can also be carbon limited and have been shown not only to benefit from increased CO2 but in some cases capable of offsetting local OA, raising estuarine pH and helping to oxygenate warming estuaries as a result of increased photosynthetic activity. It is difficult to predict how the myriad impacts of climate change will affect seagrasses in the future, but it is clear that the many ecosystem services they provide will be more important than ever in the function and resilience of Florida’s marine and estuarine ecosystems.