Evolution and environment of Caribbean coastal ecosystems

Area of Science:

• Marine Biology
• Paleoceanography
• Evolutionary Ecology

Background:

• The closure of the Isthmus of Panama in the late Pliocene isolated the Caribbean Sea from the Eastern Pacific.
• This geological event caused significant biotic shifts and extinctions in the Caribbean, but the drivers remained unclear.

Purpose of the Study:

• To investigate the impact of historical oceanographic changes on Caribbean biota following the Isthmus of Panama's closure.
• To test hypotheses linking environmental shifts, specifically reduced upwelling, to biological responses in marine communities.

Main Methods:

• Analyzing historical oceanographic data, including temperature fluctuations, to infer changes in upwelling intensity.
• Correlating environmental changes with documented shifts in marine species' feeding ecology, life histories, and habitats.
• Examining spatial patterns of biotic change and applying metapopulation theory to understand extinction dynamics.

Main Results:

• A sharp decline in ocean upwelling intensity was identified as a key environmental change.
• Reduced upwelling led to decreases in suspension feeders and predators.
• Proliferation of seagrass and coral reef habitats, and shifts in reproductive strategies of invertebrates, occurred with a time lag of over one million years.

Conclusions:

• Declining upwelling due to the Isthmus of Panama's closure significantly restructured Caribbean marine ecosystems.
• Biological responses, including habitat changes and life history shifts, exhibited considerable time lags, influenced by factors like extinction debt.