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How does climate influence the dispersal of marine organisms?

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World map using color coding to show the distribution of major floral kingdoms, subkingdoms, and regions. Key floral kingdoms include Boreal (green), Neotropical (pink), Paleotropical (yellow), South African or Capensic (purple), Australian (orange), and Antarctic (blue). Boundaries for subkingdoms, regions, and divisions are marked with different colored lines, and major regions such as Indoafrican, North American, and Malesian are labeled across continents. — biogeographic region Floral kingdoms, subkingdoms, and major regions of the world.

Climate plays a fundamental role in the dispersal of marine organisms, primarily by dictating the physical conditions of their habitats and influencing the mechanisms that transport them across the ocean.12

Temperature and Distribution

Temperature is a critical factor in marine biogeography because it influences the metabolic rates and survival of organisms. Many marine species are distributed along specific climatic lines, often migrating poleward to remain within their optimal temperature ranges as waters warm. For example, during the Holocene, various planktonic foraminiferans migrated thousands of kilometers to track favorable thermal habitats. Conversely, when temperatures exceed an organism's tolerance, it must either relocate or face physiological stress, such as the disruption of cellular respiration or the inability to survive in low-oxygen conditions associated with warmer water.2341

Ocean Currents and Transport

Climate influences dispersal through its effect on ocean currents, which act as primary vectors for the movement of larvae and small organisms. Atmospheric circulation patterns, driven by temperature gradients, power these currents.56
* Larval Dispersal: Many marine species utilize a bipartite life cycle, spending their larval phase in the plankton, where they are transported great distances by currents like the Gulf Stream.57
* Climatic Shifts: Changes in climate can alter current velocities and directions, thereby shifting the dispersal pathways of marine life.42

Ultimately, while biogeographic regions provide a framework for understanding these distributions, they are dynamic; climate-driven dispersal mechanisms—such as the transport of tropical larvae to higher latitudes—continually reshape the composition of marine assemblages.51