Final answer:
Ocean warming affects species composition by forcing species to migrate to cooler areas, altering life cycles and interactions, and threatening biodiversity, especially in coral reefs.
Step-by-step explanation:
Ocean warming is driving changes in species composition due to warmer temperatures altering habitats and disrupting the delicate balance within marine ecosystems. As ocean temperatures increase, species shift their geographic distribution, usually moving towards the poles or higher altitudes where conditions remain tolerable. This can lead to a reduction in biodiversity, especially in sensitive environments like coral reefs, which are threatened by even modest temperature rises. Additionally, the lifecycles and interactions between different species can be altered, leading to changes in food webs and biotic interactions. For instance, changing ice and snow cover can leave certain animals, like the Arctic hare, more vulnerable to predators. Global warming also leads to rising sea levels, which can inundate shorelines and reduce island sizes, having a grave impact on the species that inhabit these areas.