By Jamison Gove
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| Grey Reef Sharks often congregate in the tens to hundreds at Jarvis Island |
There is an intimate and inseparable link between coral reef ecosystems and the surrounding oceanic environment. Variability in ocean waves, currents, temperature, salinity, and nutrient availability each play a critical role in determining not only the diversity, size, and abundance of organisms, but also the morphology (shape) of coral and algal species and the substrate they inhabit. For example, corals that are consistently battered by large ocean waves tend to be low-lying and mound-shaped, lacking the large, delicate and branching structures that are often found in more benign, wave-free environments.
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| Manta Rays, Jarvis Island |
Jarvis, in particular, is influenced by unique oceanic conditions that have a profound impact on the island's coral reef ecosystem. Owing to its location in the central equatorial Pacific, Jarvis is in the direct path of a strong, cold, nutrient-rich ocean current flowing below the surface, centered at approximately 150 meters depth. This current, known as the Equatorial Undercurrent, is spawned in the far western Pacific and flows eastward along the equator and across the entire Pacific Ocean. When this fast-moving current hits the island, deep water is forced upward to the near-surface, providing copious amounts of nutrients to the surrounding coral reef ecosystem. These nutrients are quickly assimilated by the coral, algal, and fish communities, fueling an astonishingly productive and ecologically vibrant coral reef system. Few places on earth have the oceanic conditions and biological productivity found at Jarvis, making it an ideal location for researching the interplay between coral reef ecosystems and the environment in which they exist.
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| Bottlenose dolphins are a common site at Jarvis Island |
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