Useful of the trapeziid:

Small crabs living in the South Pacific coral can help corals not die by doing regular cleaning ' services ', services that seem very important to the lives of the reefs. roaring around the world. That is the judgment of scientists at the University of California, Santa Barbara UCSB.

The relationship between crabs and corals is published in the November 2006 issue of Coral Reefs and is now available on the internet.

According to research, corals are houses and shelter and protection for crabs. The crab performs ' home care ' tasks for corals, ' sweeping ' the sludge into coral daily.

Thus, the relationship between corals and species of trapeziid is beneficial for each other, in other words a symbiotic relationship. These small crabs with a width of only about 1 cm make houses in coral polyps such as Acropora or Pocillopora. This trapeziid species study was carried out on coral reefs near the island of Polynesia in Moorea, South Pacific.

Crab trapeziid can help corals not die.

Hannah L. Stewart, the first person to carry out the study, a postdoctoral researcher at the Marine Science Institute at the University of California, Santa Barbara (UCSB's Marine Science Institute) said: ' Although we don't know Much about these crabs, but we know very well that they are 'picky and picky', always taste it before eating and see if it suits them. Then, they use their front appendages to move and clean up the mud in the coral. '

Ms. Steward added that this crab family is very popular in the world. ' This relationship can occur throughout the Pacific and may be more common in many places than we think. And because the crabs live in coral everywhere, this study contains an ecological implication, that is: crabs that are linked to corals may have a more important role than what we know. about them.'

She explained that the coral reef is one of the most diverse and useful ecosystems in the world. They are home to more than 9 million species and create 'livelihoods' for millions of people on earth.

The accumulation of mud on coral tissue reduces the metabolism and growth rate of tissue, and thus increases the risk of bleaching to corals and causes corals to die. Many corals can remove some of the sludge on their surface but too much sludge accumulation can cause them to die. The increase in the predicted amount of mud threatens the coral reefs located near the coast around the world.

Currently, environmental changes are threatening coral reefs. For example, seawater temperature and ultraviolet radiation are increasing due to climate change that causes widespread coral bleaching.

Changing land use due to population growth on the coast is also another threat to corals because population growth increases the amount of mud on corals. This is because as the population increases on the coast, the amount of wastewater from building construction, from deforestation, erodes soil and from agricultural expansion to the sea more and more.

This study was carried out on a part of the long-term ecological research area (LTER) in the Moorea reef area project (MCR). This ecological study area is located in the area of ​​a variety of salty reefs and saltwater lakes surrounding Moorea Island.

Ms. Stewart conducted this study with Sally Holbrook, professor and associate professor of marine ecology, evolution and biology at the University of California, Santa Barbara, Mr. Russell Schmitt, professor of ecology and evolution. and marine biology, director of coastal research center of MSI Institute and Mr. Andrew Brooks, MSI biologist, deputy director of MCR LTER area. Tests were performed on coral reefs as well as in laboratories.

Scientists have demonstrated the importance of trapeziid by gently bringing crabs out of their habitats on two coral polyps of underground coral reefs along the coast. And as a result, 50 to 80% of those corals die within less than a month. In contrast, corals living with crabs still exist.

Only when this study is done can the nature of this common symbiotic relationship be realized. Because corals exist without crabs, coral reefs are less developed, more bleached coral tissues become more and more accumulated sludge is getting thicker.

Laboratory tests show that corals living with crabs basically eliminate not only the sediments on the coral's surface, but also remove the particle sizes that affect the coral tissue. Best. These are the largest sized particles studied by scientists, ranging from two to four millimeters across. (The particle size here refers to the mechanical size of soil, rock or other solids. It is different from the crystal size that is the size of a single crystal in solid (a particle can contain many crystals. Particle size can range from very small like candy particles to clay, mud, sand, gravel or pebbles.)

The MCR project for the LTER long-term ecological research area funded by the National Science Foundation (NSF), is a research collaboration between the University of California, Santa Barbara and California State University, Northridge.