User:Rew21/Zooxanthellae

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Clams and Zooxanthella

Coral is not the only aquatic organism to be affected by bleaching and the expulsion of zooxanthella, clams have also been found to undergo a similar process when temperatures become too high. However, clams discard zooxanthella that are still alive and have been observed being able to recover them. This not only has positive indications for the clams themselves, but also the surrounding ecosystem. For many organisms, clams are a vital part of the food chain. Not only can they themselves be eaten, but excrement from giant clams contains live zooxanthella. Opportunistic feeders and clams alike use excreted zooxanthella as a nutrient source. The consumption of zooxanthella is especially vital for a clam in its veliger stage as it encourages growth. . Zooxanthella are not only found in clam excrement, but in the mantle tissue as well where they take up ammonia and nitrate ( https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.319.8893&rep=rep1&type=pdf ). They are also found in the eyes of clams like Tridacna where they act as a lens ( https://www.osti.gov/biblio/6701276 ). Different clades of zooxanthella have an impact on clam morphology. Clade E1 of zooxanthella seems to influence or favor smaller offspring from clams when compared to clams harboring other clades and all five clades appear to be needed in order for larval settlement to occur ( https://doi.org/10.3389/fmars.2021.633761 ).

Jellyfish and Zooxanthella

Jellyfish and zooxanthella have a history together in the scientific world as Symbiodinium was first cultured from the jellyfish Cassiopea, a model  jellyfish species. Many different types of zooxanthella have been observed forming relationships with jellyfish across many different phylogenetic branches, and the roles they play will change throughout the jellyfish’s life cycle. However, as the jellyfishes ages, the diversity of zooxanthella attaching to them decreases, suggesting that zooxanthella compete with each other to form relationships with the jellyfish. Not all jellyfish form relationships with these microbes and for the most part the ones that do are found in tropic and subtropic waters. The relationship between jellyfish and zooxanthella is affected a little differently than coral in terms of climate change despite both of them being a part of the cnidaria family. ( https://link.springer.com/article/10.1007/s00227-019-3581-6 ). One study suggested that certain species of jellyfish and their symbiotic zooxanthella may have some type of resistance to decreasing pH caused by climate change to a certain point ( https://onlinelibrary.wiley.com/doi/epdf/10.1111/ivb.12255 ). Although, jellyfish bleaching events have been documented during extreme heat events. ( https://link.springer.com/article/10.1007/s00227-019-3581-6 ). While the causal factors that normally seem to affect the relationship between zooxanthella and their host may not apply to jellyfish, light intensity does. Light availability can affect the lipid production of zooxanthella that the jellyfish then utilize ( https://www.sciencedirect.com/science/article/abs/pii/S0022098109002718 ). To maximize their light uptake, jellyfish will both swim near the surface and do very specific migrations. The migration patterns also assist with helping the zooxanthella access specific nutrients. Many of these jellyfish appear to be mixotrophic consuming both live prey and utilizing phototrophy. This may be what helps jellyfish survive climate change and bleaching as they could switch feeding methods rather than attempting to recover lost zooxanthella quickly. There are many unknowns in when it comes to the relationship between zooxanthella and jellyfish that scientists look to answer. ( https://link.springer.com/article/10.1007/s00227-019-3581-6 ).