The year of the reef

Each diver knows that coral reefs provide a huge variety of colors and shapes for the interesed observer. The year 2008 was declared as the international year of the reef. This year will have events and actions to increase the knowledge about corals and their function in the ecosystem. The official german website is IYOR2008.

Actions

In Germany the international year of reefs started at the Boot'08 watersports exhibition in Düsseldorf (Pressemitteilung) where the general dirctor of the museum for natural history of the Alexander von Humbold University, Dr. R. Leinfelder, held a lecture (Corals - fascination and obligation (PDF)) at the instructors meeting day of the german diving association (VDST). This presentation is just one of several planned actions during this international year of reefs.

Special exhibiton at the Natural History Museum, Alexander von Humboldt-University in Berlin

The exhibition 'descended' in the Natural History Museum is open from the 08th of April to the 30th of September 2008. The aim of this exhibition is to introduce the visitor to the complexity and diversity of coral reefs. ('descended' in the natural history museum HU-Berlin)

Reef cleaning

Several diving bases organize cleaning actions in and around reef-associated diving-spots. Trash will be collected from the beaches and the reefs by divers. This action will show the amount of trash that accumulates in coral reefs and that needs to be removed from time to time. (IYOR)

Reef Check in Egypt

The global longterm Reef Check program will have an event at the 08th of may in Marsa Alam. There at the Red Sea will be an assessment of the condition of local reefs. Reef Check is a world wide project of scientists and the population. A more comprehensive summary on Reef Check can be found at 'useful things' or the german homepage of reef check.

Distribution of coral reefs

Since a few years the common rule was in force that coral reefs can only be found at the tropical zones with watertemperatures never falling below 20°C. This represented the main distrubution area of tropical coral reefs on our planet. A few years ago however, the scientific world was suprised by the fact that in the cold Norwegian sea cold water corals forming large expanding reefs were found. These reefs are not situated close to the surface, but can be found in larger depth. Cold water reefs also contain a large species diversity that scientists just stared to assess.

Warm water corals

The warm water corals are circumglobally distributed along the equator and in the southern pacific. These coral reefs are built by small single individual polyps, which live in large colonies. Each polyp itself builds a sceleton out of limestone and in total all individuals together have for example built the largest biogenousl structure on this planet, the 'great barrier reef' in Australia.

Polyps of warm water coral do contain symbiontic algae, so called 'zooxanthellae'. These symbionts do use the sunlight for primary production and provide their metabolic products to the polyp on exchange of nutrients and protection.

The distribution area of warm water corals is determined by the water temperature, which needs to be above 20°C all year. Best growing conditions for most coral species are temperatures between 25 and 30°C.

The coral species belong to the phylum Cnidaria and to the class Anthozoa. There are two different groups of coral building polyps, while only the Scleractinia actually building reefs. Representatives of the group of soft corals in the Baltic sea are anemones (Actiniaria) like the plumose anemone (Metridium senile) or the dahlia anemone (Urticina sp.).

Cold water corals

The real importance and spreading of cold water reefs has just been in the focus of interest for the last couple of years. These reefs are mainly built by non symbiontic coral species without photosynthetic cells like Lophelia pertusa and Madrepora oculata. These reefs can be of impressive size. So far the Sula-ridge in the Norwegian Sea of the North Atlantic is the largest known cold water coral-reef with 13 km length and 400 to 600 m width. Cold water corals prefer temperatures between 4 and 11°C and occur mostly in depths between 200 and 300 m. In the Norwgian fjords they can also be found closer to the surface up to 50 m depth.

Links

Brochure of the governmental agency