Molecular plasticity, ocean warming and the relationship with coral reef fish

An interesting new in-depth study has done a retrospective on this issue

by Lorenzo Ciotti
Molecular plasticity, ocean warming and the relationship with coral reef fish
© Lukasz Larsson Warzecha / Stringer Getty Images

Molecular plasticity, ocean warming and the relationship with coral reef fish: what is the relationship between them? The authors of the study Molecular plasticity to ocean warming and habitat loss in a coral reef fish, published in the The Journal of heredity, explained:

"Sea surface temperatures are rising at unprecedented rates, leading to a progressive degradation of complex habitats formed by coral reefs. In parallel, acute thermal stress can lead to physiological challenges for ectotherms that inhabit coral reefs, including fishes. Warming and habitat simplification could push marine fishes beyond their physiological limits in the near future, questions remain on how warming and habitat structure influence the brain of marine fishes.

Coral reef
Coral reef© Donald Miralle / Staff Getty Images

Atlantic, Abudefduf saxatilis. For this experiment, 40 individuals were exposed to different combinations of temperature (27°C or 31°C) and habitat complexity (complex vs simple) for 10 days, and changes in brain gene expression and oxidative stress of liver and muscle were evaluated. The results indicated that warming resulted in increased oxidative damage in the liver (p=0.007) and changes in gene expression of the brain including genes associated with neurotransmission, immune function, and tissue repair.

Individuals from simplified habitats showed higher numbers of differentially expressed genes, and changes for genes associated with synaptic plasticity and spatial memory. In addition, a reference transcriptome of A. saxatilis is presented here for the first time, serving as a resource for future molecular studies. This project enhances our understanding of how fishes are responding to the combination of coral reef degradation and thermal stress, while elucidating the plastic mechanisms that will enable generalists to persist in a changing world."

Unfortunately, these ecosystems are very fragile and are threatened, directly or indirectly, by human activity. Trawling and anchors can significantly damage them, while the indiscriminate use of poison to stun fish and the aquarium trade has caused in some areas a patchy die-off of the octopuses found in the area.