1/9/2024 0 Comments Undisturbed synonymThe Mesozoic was dominated by sponges, corals, rudist bivalves, and algae, most of which were eliminated in the end-Cretaceous extinction event. The major extinction event at the end of the Paleozoic eliminated these forms as reef constituents and new groups (e.g., the first scleractinian corals) appeared in the Triassic. Paleozoic reefs consisted of sponges, corals, foraminifera, algae, bryozoans, and brachiopods, among others. These reef groups varied over geologic time with extinction events commonly marking dramatic changes in the biotas. Evolution of these groups continued unabated and sometimes resulted in significant changes in the communities making up reefs. Reef-inhabiting organisms included many different groups from algae to vertebrates as well as enigmatic, extinct suprageneric taxa. From then until the Recent, reefs diversified, underwent extinctions many times and then diversified again. Another big uncertainty is how much loss of biodiversity will occur with the inevitable degradation of coral reefs that will continue in most places for the foreseeable future.Īlthough reef-like structures formed in the Neoproterozoic, reefs built by metazoans did not appear until the early Paleozoic. How long reefs can continue to bounce back in the face of warming and acidification remains an open question. Today, much of this failure to recover appears to stem from the fact that most reefs are chronically stressed by human activities, judging by observations of recovery at exceptional locations where local human activity is minimal. In the present, coral reefs sometimes respond dramatically to disturbances, and collapses are not always followed by recoveries. Reefs have a long fossil record, although extensive reef building comes and goes. Networks of competitive and trophic linkages are also exceptionally complex and dense. This diversity, which remains very poorly understood, is nevertheless extraordinary when one considers the small proportion of ocean area that is occupied by coral reefs. Coral reefs are the most biodiverse marine ecosystems on the planet, with at least one quarter of all marine species associated with reefs today.
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