Marine Ecology

Tropical Biodiversity and Microbiomes

Coral reefs teem with biodiversity – ranging from microbial to multicellular – and the complex continuum of interactions between entities, like the healthy reef system in French Polynesia pictured in the research topic photo and Fig. 1 here. Since 2014 we have been sampling in the Caribbean to develop baseline information on the microbial communities that are found in the waters surrounding reefs, salt ponds and mangroves (Fig. 2).

(Fig. 1) Coral reef with Acropora colonies near Moorea island, French Polynesia. These corals have symbionts that are released during bleaching events - and of course microbiomes, as a collective this suite is termed the Holobiont. Photo: K Bergauer
(Fig. 2) The mangrove pictured here is actually a coastal mangrove forest on Moorea island, French Polynesia - but there are lots in Curacao as well allowing comparison of the associated microbial communities. Photo: K Bergauer

This involves annual field sampling, with studies from diversity analysis, to coral feeding physiology and microbe-microbe interactions. Because we are interested in time-series, much of this work is yet to be published. For example, CAU/GEOMAR MS student Jessica Eberle is working to characterize the salt pond communities (Fig. 3), and a number of OEB members are analyzing experiments and other aspects of biodiversity.

(Fig. 3) Sampling salt ponds in Curacao during a trip with the King Lab (UCB) – this sample isn’t for DNA analysis but rather for the microscope! Photo: AZ Worden.
(Fig. 4) A salt pond in Curacao – lots of algal growth! This particular pond can have crystal clear waters or dense growth depending on the year - we are working on what underpins this shift. Photo: AZ Worden

We utilize the CARMABI field station (Fig. 4; an amazing resource in this region) with a wonderful suite of collaborators – including Forest Rohwer, Patrick Keeling, Nicole King, Tom Richards and Alyson Santoro. In this collaboration, we agree to meet there and work in a loose framework – but one where there can be rich exchanges that arise out of places other than premeditation. We perform our sampling by foot (Fig. 5), kayak and small boats in these systems. 

(Fig. 5) The view from the CARMABI field station in Curacao where we study microbial communities that surround reefs, extending to mangroves and salt pounds – and comparative work to understand coral microbiomes. Photo: K Hoadley

Other research in this area: Recently Dr. Kristin Bergauer expanded the tropical biodiversity topic to also study these habitats in Moorea through collaborations in the BIOGAPS program (Fig. 6).  We also have been examining the microbiomes of corals and other invertebrates – but in this case with a focus on deep sea (cold water!) corals (Dark Ocean Theme). A long-term aim is to compare the different coral and invertebrate microbiomes across the ocean.

(Fig. 6) Our studies involve many collaborations – here are the institutes involved in BIOGAPS. Map: K Bergauer.