While global media focus on the bleaching of coral structures in Australia’s Great Barrier Reef, scientific partners in the Dutch AcroporaNet project since 2014 have been researching the state of tropical marine coral in the Caribbean near Saba and Statia. Do reefs in that region grow or erode? And what’s the role of bioeroding sponges?

Climate change and overfishing, but also local factors such as eutrophication, pollution, land reclamation, and maritime construction are under the microscope of the AcroporatNet collective. The participants gathered within the initiative together share the goal to contribute to the sustainable management and use of tropical marine resources through fundamental and applied scientific research and advisory work.

Phoram fishing

The Dutch Caribbean Netherlands Science Institute (CNSI), a facility on Statia that fosters scientific curiosity and supports scientific research, is at the heart of field expeditions. Recently AcroporaNet teams undertook several excursions to the Saba Bank, a gigantic 2200 km2 atoll next to Saba, to see if coral systems there are growing or eroding.  

Part of the research was an experiment on the sea floor with a tent at 20 m depth, monitoring a small part of the reef. Another test focused on conducting growth experiments with planktonic foraminera, unicellar organisms that create a little carbonate shell. Prime interest was to learn how foraminifera respond to living in a warmer, saltier or more acidic ocean.

Experience the catching of these phorams? Dive along with Alice Webb and Didier de Bakker.  

Research results

“Our findings strongly suggest coral mucus fuels a sponge loop in both warm water and cold water reef ecosystems”, says marine microbial ecologist dr. Fleur van Duyl, senior scientist at the Royal NIOZ and board member of AcroporaNet. “Environmental and human impacts, such as increased sedimentation and ocean acidification may lead to changes in mucus production, and could thereby further influence organic matter transformation by the sponge loop. That may pave the way for increased bioerosion of Caribbean coral reefs ” 

PhD student B. Müller, part of the AcroporaNet team, will be ‘Shedding light on DOC release by benthic primary producers and its consumption by bioeroding sponges’ in his thesis shortly. 

Visit the website of AcropoNet for the latest news and information