Coralscience.org is currently building a system which will mimic the mesophotic reef zone. Mesophotic coral reefs are light-dependent (sub)tropical coral communities that occur in the deepest half of the photic zone, and therefore receive little sunlight. Starting at 30-40 m (100 - 132 ft) and extending to over 150 m (500 ft), these reefs have received little interest due to their secluded existence. Mesophotic reefs are inhabited by highly interesting benthic species such as sponges, feather stars, bryozoans, tunicates, aposymbiotic (soft) corals and black corals. These so-called filter and suspension feeding animals are the main focus of our studies.

Stony corals such as Leptoseris and Montipora spp. also occur in the mesophotic zone, even though light levels be may as low as 1% of the sunlight irradiance experienced at the surface! This shows that even zooxanthellate corals can adapt to very low light intensity levels, as long as this is compensated by heterotrophy such as plankton feeding.

Why study reef organisms besides corals?

Although corals are the most popular marine invertebrates amongst hobbyists, a coral reef harbours so much more than just these colourful organisms. A reef is a complex, dynamic system, inhabited by a myriad of marine species. The development of aquarium systems aimed at maintaining a rich diversity of marine life is paramount to successful conservation and education.

The main problem is that many coral reef species require extensive plankton feeding, making it challenging to maintain high water quality. Recent technological improvements however have made it possible to combine heavy feeding practices with high water quality. These include bacterial filters designed to immobilise excess nutrients and greatly improved sand beds.

Right: A colony of tunicates, Neptheis fascicularis. These animals are true filter feeding organisms.

The last couple of years have seen important milestones in the husbandry of coral reef organisms. Species which have survived—and even thrived and grown— for prolonged time include azooxanthellate stony corals (Tubastrea coccinea, Dendrophyllia spp., Leptopsammia pruvoti) azooxanthellate gorgonians (Menella and Swiftia spp.), crinoids (Comanthina sp.), black corals (Stichopathes and Cirrhipathes spp.), sponges (Trikentrion flabelliforme, Haliclona spp.), hydrocorals (Distichopora violacea) and tunicates (Neptheis fascicularis).  

Coralscience.org is currently building a system designed for the successful husbandry of several of the species listed above. Within several months, we will publish more details about this ongoing project and release photographs and videos. Stay tuned!

Find out more about the importance of mesophotic coral reef ecosystems at www.mesophotic.org.

This project is being realised thanks to our proud sponsors: