BONAIRE – Under the name Bonaire Deep Reef Expedition I, from May 30th to June 1st 2013 the deep reef of Bonaire was explored by researchers from IMARES Wageningen UR. The aim was to document this fascinating ecosystem and its unique biodiversity using cameras and collecting biological specimens. The shallow reefs of the Southern Caribbean are considered a biodiversity-hotspot, an area with exceptional diversity of plants, animals and ecosystems, yet surprisingly little is known about the flora and fauna of the deep reefs. The Dutch Ministry of Economic Affairs commissioned the research institute IMARES to study the deeper reef as part of the Exclusive Economic Zone management plan for the Dutch Caribbean.
IMARES’ researchers Erik Meesters and Lisa Becking boarded the submarine “Curasub” owned by the Curaçao Sea Aquarium and descended to depths of 200 to 250 metres at three locations on Bonaire: the Town pier, the Salt pier and the Te Amo pier. The researchers found that coral reef extend until approximately 45 metres. The reef zone is followed by a sandy zone from 50 to 90 metres depth covered by a cyanobacterial mat. The cause of this ‘cyano-mat’ remains unclear and warrants further investigation. At depths below 90 metres, sand dominated the scenery. There were, however, also patches of fossil reef which must have formed during previous ice ages when the sea level was much lower than it is today. By providing hard substrate, these fossil reefs provided oases of biodiversity in a desert landscape of sand.
Special attention was paid to the invasive Lionfish. Between depths of 80 to 115 metres Lionfish were seen sporadically in schools of 10 to 20 individuals clustered together, but individuals or pairs of Lionfish were observed as deep as 165 metres, often swimming exposed above open stretches of sand.
Besides biological discoveries the researchers also discovered some archaeological objects, such as an 18th century Spanish olive urn.
During the submersible dives examples of sponges, soft corals, gorgonians, echinoderms, fish, and mollusks were collected. These will be identified with the aid of taxonomists at Naturalis Biodiversity Center and the laboratory at Naturalis will generate “DNA-barcodes” to facilitate future identification. This work is likely to result in the identification of several species new to science. Information on the deep reef habitat structure and biodiversity is essential to adequately protect the ecosystem and construct sustainable management plans. In order to protect biodiversity, it is essential to have a good understanding of what is down there and what processes keep it in place.
