Saba bank expedition 2016

NIOZ organised an expedition to the Saba Bank aboard the research vessel Pelagia from 19th August to 8th September 2016. Thirteen AcroporaNet scientists from NIOZ, Wageningen Marine Research, TU Delft, UvA and Utrecht University set out to investigate how environmental conditions are impacting the coral reef ecosystem functioning on the Saba Bank.

The goal of NIOZ's Saba Bank expedition is to understand the interaction between the environmentand coral reef functioning. Researchers aim to better understand the hydrography and to determine if net ecosystem calcification occurs the SabaBank. In other words is the Saba Bank growing or eroding and which factors can explain these processes?

Healthy coral reefs exist in dynamic environments in which its primary builders, corals, experience a balanced growth (calcium carbonate (CaCO3) production) and erosion. Corals are exposed to bioeroding organism such as sponges, worms and parrotfish scraping off the associated algae or directly degrading the reef’s carbonate skeleton. For example coral excavating sponges are reported to be the most important bioeroding organism in the Caribbean often killing the corals when competing for space. A variety of human-induced pressures cause ocean acidification and eutrophication of the marine environment. This negatively affects corals and other carbonate producing organism living on our reefs.

Recent studies have demonstrated that ocean acidification not only weakens the calcium carbonate skeleton of coral but also increases sponge biomass and therefore the rate of reef erosion. Thus, a primary threat of ocean acidification is the potential that eroding processes exceed the production rate of CaCO3, thereby resulting in the loss of corals. It is however not known exactly how and to what degree (combined) climate change impacts and other environmental conditions are affecting different benthic organism such as sponges and how this influences the carbon metabolism of reef ecosystems.

The Saba Bank is an excellent study site to investigate these processes due to its’ remoteness, large shallow area and cover of corals, benthic algae, sponges and gorgonians.

To answer these questions,many different experiments and (long-term) measurements have to be taken to understand the functioning of this complex system. The most important component of this recent expedition was to find horizontal and vertical gradients related to calcium carbonate production and loss such as seawater chemistry (e.g. dissolved oxycan, alkalinity, nutrients), currents, light, dissolved and suspended organic matter (phytopigments and particulate organic matter POM) and pico-and nano- plankton concentrations. This data will be assessed to determine how these gradients are linked to the benthic composition of calcifying and non-calcifying organism. All these measurements will be used to calculate the net calcium carbonate production in different areas on the SabaBank.

Researchers aim to understand the carbon metabolism of reef ecosystems and the role of bioeroding sponges in dissolution of CaCO3 in relation to ocean acidification and eutrophication and other environmental factors. The expedition data are now being processed and analyzed and resulting papers and publications will be listed in future editions of BioNews. Expedition Saba Bank 2016 is one of a serie recent expeditions published in a special issue of BioNews. 

BioNews 29-Oct 2016 takes a look at recent research expeditions to the Dutch Caribbean. 

 

Latest News

Monday 9 January 2017

Fleur van Duyl

Royal NIOZ

〉Article Saba Bank

Photo album 2016

RV Pelagia
Investigating the corals

Go back