A team of researchers from various international universities showed that the eastern tropical coral populations from the Pacific had been isolated for at least two decades, making the reef survival to be a challenge.
The ocean currents can change their direction and their speed with the season or climatic events such as El Nino.
The study was led by researchers from the University of Bristol and used a computer model to monitor the coral larvae that traveled along with currents. The corals are releasing eggs that can be then fertilized in the water and form larvae with the size of poppy seeds.
The team of scientists noticed that during the El Nino event from 1998, the larvae could not survive to reach the reefs from the central Pacific which were situated almost 3,000 miles away.
According to Charles Darwin’s theory, the open ocean is impassable. However, recent arguments showed that the East Pacific Barrier should be passable because the same coral species had been found on both sides.
However, the present research indicates that the corrals have not been able to pass the barrier anymore, making the reef survival become an issue.
The corals managed to build the reefs and created a habitat that supports a diverse ecosystem.
The authors of the study explain that the coral’s ability to reproduce and disperse its larvae is a major factor in their survival and adaptation to the pressures of warming climate.
Travelling is important because it permits the corals to replenish the damaged populations, to colonize new areas and to move out from threatening conditions. However numerous coral larvae are, they have a very slight chance is finding a suitable place to form a colony.
The scientists had a hard time in monitoring the larvae, especially because they are too small, and they cannot be tracked like the large marine animals are done. They have overwhelming in numbers, and they are as small as a plant seed. Therefore, the researchers used computer simulation to track the routes of the corals.
The study used a model involving five billion larvae situated in 636 reefs around the Pacific Ocean and followed their hypothetical movements for a period of 14,5 years. All this was possible by using the BlueCrystal supercomputer from the University of Bristol.
The initial theory was that El Nino events could help the dispersal of coral larvae on long distances across the Pacific Ocean. However, the results of the computer simulations showed that the eastern Pacific corals had been completely separated from the rest of the ocean, at least since the 1998 El Nino.
The 1998 event killed a lot of corals from Baja California up to the coastline of Ecuador and Galapagos Islands. In such situations, the corals recover by colonizing new territories. Therefore, the isolation became a challenge for reef survival.
The conclusion of the study is that the isolated coral reefs from the eastern Pacific Ocean must be protected against the climate threats.
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