The Red Sea

A recent study has found that Global Warming is slowing the growth of Coral in the Red Sea, and all growth could stop by the year 2070.

By utilizing CT (computed tomography) scans, some scientists over at the WHOI (Woods Hole Oceanographic Institution) have found that the greenhouse effect (which is the leading cause of global warming) is killing off one of the predominant species of coral in the Red Sea.

The summer temperatures on the sea surface remained at roughly 1.5 degrees Celsius above what’s the norm for the past ten years. The growth of the coral, Diploastrea heliopora, has seen a marked decrease of 30% and as has been quoted by scientists, “could cease growing altogether by 2070” or even sooner, as the research team quoted in the July 16th issue of the journal Science.

“The warming in the Red Sea and the resultant decline in the health of this coral is a clear regional impact of global warming,” said a WHOL postdoctoral investigator, Neal E. Cantin, who is also the co-lead researcher on the project. In the 1980s, he explained, “the average summer [water] temperatures were below 30 degrees Celsius. In 2008 they were approaching 31 degrees.”

This could spell some big trouble for the Red Sea. If the Coral is being affected in such a way, what of the other species? Could it be that the Red Sea will become another DEAD Sea in the very near future? Scientists are working round the clock on a solution for Global Warming, but it seems a solution is still years from being worked out, and in the meantime we are losing out.

The Jordanian government has announced its plans to extract over 10 billion cubic feet of water per year from the Red Sea and send most of it to a desalination plant to produce drinking water. The salty wastewater will then be sent from the desalination plant to the Dead Sea by tunnel. Jordanian Water Minister Maysoun Zu’bi says the project will begin as soon as funding has been arranged.

Environmentalists warn that the endeavour could damage the ecosystem of both seas. Mixing two types of saltwater could produce algae blooms in the Dead Sea, and some environmentalists also fear that the extraction of saltwater will increase the Salinity of the Red Sea.

Dead Sea info

The Dead Sea is a salt lake shared by Jordan and Israel. Its surface and shores are 422 meters below sea level, which is the lowest elevation on the Earth’s surface on dry land. With almost 34% salinity, the Dead Sea is one of the saltiest bodies of water in the world and 8.6 times as salty as the ocean.

During recent decades, the Dead Sea as shrunk rapidly, chiefly due to the diversion of incoming water from the Jordan River. The diverted water is used for households, agriculture and industry. In 1970, the Dead Sea was 395 meters below sea level. In 2006, that number had increased to 418 meters.

The Dead Sea level drop has been followed by a drop in groundwater level and large sinkholes have begun to appear along the western shore.

Zoology Prof. Yossi Loya at the Tel Aviv University in Israel has discovered that corals changes sex to survive periods of stress, such as high water temperatures. By observing the behaviour of Japanese sea corals he discovered that stressed female mushroom coral (fungiid coral) change gender to become males, and that male corals are much better at handling stress and fare better at surviving on limited resources. Not all females go through his change but many do and most of the population is therefore male during periods of intense stress.

Yossi Loya says: “We believe, as with orchids and some trees, sex change in corals increases their overall fitness, reinforcing the important role of reproductive plasticity in determining their evolutionary success. One of the evolutionary strategies that some corals use to survive seems to be their ability to change from female to male, As males, they can pass through the bad years, then, when circumstances become more favourable, change back to overt females. Being a female takes more energy, males are less expensive to maintain. They are cheaper in terms of their gonads and the energy needed to maintain their bodies. Having the ability to change gender periodically enables a species to maximize its reproductive effort.”

Loya’s discoveries have been published in the Proceedings of the Royal Society B. The professor hopes that this new knowledge will help coral farmers by allowing them to reproduce the hardy Fungiid corals more effectively.

Loya has been studying coral reefs for more than 35 years and won the prestigious Darwin Medal for a lifetime contribution to the study of coral reefs. He is also involved in coral rehabilitation projects in the Red Sea and is a professor at the Tel Aviv University in Israel.

A new species of giant clam has been encountered by researchers in the Red Sea and given the name Tridacna costata. The new species is fairly similar to two other well-known species of Red Sea clams and it was therefore first suspect to be a hybrid, but genetic analysis has now deemed it a separate species. Further research carried out in the Red Sea also supports this; there are significant differences in behaviour between the two other species and the newly discovered clam. The two previously known clams spawn during a long period in summer while the new clam spawns during a short period in spring.

Fossil evidence uncovered by researchers has now unveiled something even more interesting; Tridacna costata might be one of the earliest examples of marine overexploitation by humans. Fossil records suggest that the Red Sea Tridacna costata population began do decline rapidly roughly 125,000 years ago. This is the part of our early history when scientists believe modern humans to have first begun to migrate out of Africa. Before this point in history, Tridacna costata accounted for over 80 percent of giant clams in the Red Sea – at least according to current fossil studies. Tridacna costata is a two feet long clam and it is not unreasonable to suspect that it would have been a splendid catch for early humans in search of food. Today, the species is believed to constitute less than one percent of giant clams, but this figure can of course change as the Red Sea becomes even more thoroughly explored.

Tridacna costata is the first new living species of giant clam found in two decades and was accidently discovered by scientists engaged in a Tridacna maxima breeding project. Tridacna maxima, another giant clam, is a much sought after clam in the aquarium trade.

If you want to find out more, the researchers behind the finding have posted their article online in the journal Current Biology on August 28.

Scuba diving tourists are an important source of income for Egypt, but now the tourism sector might be sawing off the branch on which they’re sitting by over-exploiting the sensitive coral reefs of the Red Sea. According to a study by Hasler and Ott, heavily dived dive sites near the town of Dahab have a significantly lower level of coral cover compared to areas without recreational diving.

Located off the south-eastern coast of the Sinai Peninsula, the reefs of Dahab is one of Sinai’s most treasured and well visited diving destinations. Dahab is still a fairly small town, but it is situated no more than 80 km (50 miles) from Sharm el-Sheik, a bustling tourist hub which attracts tens of thousands of visitors each year. Some of the dive sites off Dahab are among the world’s most heavily dived sites with over 30,000 dives per year.

According to Hasler and Ott, heavily dived sites in the studied area exhibited a reduced coral cover compared to non-dived sites and there were also significantly higher levels of broken and damaged corals. Differences could also be observed within the same reef, with coral communities located on reef crest areas being significantly more damaged than coral communities growing on reef slopes.

Divers are not only causing trouble by damaging corals directly; they can also stir up the sand around the reefs, thereby promoting sedimentation on top of the corals. Attached corals cannot free themselves of sediment particles and being covered in sand is therefore very dangerous for them.

In order to combat the problems faced by heavily exploited reefs, Hasler and Ott have suggested implementing ecologically sustainable dive plans for individual sites and limiting the total amount of dives per year. According to the authors, it is also very important to educate dive guides and divers.

For more info, read the results of the study which are due to be published shortly in Marine Pollution Bullentine. “Hasler H and JA Ott (2008) – Diving down the reefs? Intensive diving tourism threatens the reefs of the Northern Red Sea. Marine Pollution Bulletin, 2008 Aug.”