About:

 

General - Research Interests - PhD project -

Impressions from the field - Publications

 

General:

2009	Diploma in biology (equivalent to MSc.) at the University of Rostock, Germany
2009 to 2010	Junior expert in marine biology and aquaculture with the German Development Service (DED) in the Philippines
Since 2010	PhD student at NIOZ investigating the functional role of excavating sponges on Caribbean coral reefs

 

Click here for detailed CV  cv_benjamin_mueller_oct2012.pdf

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Research Interests:

• Dissolved Organic Carbon (DOC) production by benthic primary producers on coral reefs

• Uptake of DOC by (excavating) sponges

• Organic Carbon cycling on coral reefs

• Bioerosion by excavating sponges on coral reefs

• Ecology of Asteroidea

• Management of crown-of-thorns sea star (Acanthaster planci) outbreaks

 

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PhD Project:

Within the EU-funded FORCE project (Future of Coral Reefs in a Changing Environment) I am investigating the functional role of excavating sponges on the coral reefs of Curaçao and Bonaire.

Under the supervison of Dr. Fleur van Duyl I am aiming to answer the following research questions:

1. Do benthic algae exude more dissolved organic carbon (DOC) than scleractinian corals per unit surface area of reef?

2. Do excavating sponges take up DOC as a vital part of their nutrition?

3. Do elevated DOC concentrations stimulate the growth and bioerosion rates of excavating sponges?

Background:

Sponges play an important role in the nutrient dynamics on coral reefs. In general they are opportunistic feeders, feeding on plankton and DOC (e.g. De Goeij et al. 2008 ; Van Duyl et al. 2011). Sponge abundance and cover on reefs appear to increase on coral reefs throughout the Caribbean, most likely related to eutrophication. An ongoing phase shift from previously coral-dominated to increasingly macroalgal-dominated reefs is likely to increase the amounts of detritus and DOC released from reefs. This “surplus” food, DOC in particular, may favor the nutrition and growth of sponges including excavating sponges.

 

Phaseshift from a coral-dominated (left) to a algal-dominated coral reef (right)

 

Excavating sponges are generally dominating the bioeroder community on tropical coral reefs (Risk et al. 1995, Calcinai et al. 2000). They can kill live corals and are known to remove large amounts of calcareous material from the reef framework (up to 22 kg CaCO₃ m^-2 year^-1). Thereby, they are weakening the foundation of coral reefs and contribute to the reduction of their 3-D complexity.

 

Common excavating sponge species on the coral reefs of Curçao and Bonaire

 

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Impressions from the field:

Most field work and lab experiments were conducted around the CARMABI research station on Curaçao.

 

A first step was to identify dominant species of excavating sponges and to quantify their abundance on the coral reefs of Curaçao and Bonaire. 

 

DOC concentration around coral and algae were determined in situ by SCUBA.

 

DOC release of corals and algae were quantified in incubation experiments.

 

Excavating sponges were extracted from the reef frame work and transported to the Carmabi research station for lab experiments.

 

Bioerosin rates of excavating sponges were quantified in the lab and in the field.

 

So far, 4 MSc. students participated in the research project.

 

Findings were presented on international conferences in form of oral and poster presentations

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Publications:

Meesters E.H., Mueller B. & Nugues M.M (in press). Caribbean free-living coral species co-occurring deep off the windward coast of Curaçao. Coral Reefs (DOI: 10.1007/s00338-012-0960-6).

Bos A.R., G.S. Gumanao. B. Mueller, M.M. Saceda (in press). Management of crown-of-thorns sea star (Acanthaster planci L.) outbreaks: removal success depends on reef topography and timing within the reproduction cycle. Ocean and Coastal Management (DOI 10.1016/j.ocecoaman.2012.09.011).

Bos A.R., G.S. Gumanao. B. Mueller, M.M. Saceda, 2012. Size at maturation, sex differences, and pair density during the mating season of the Indo-Pacific beach star Archaster typicus (Echinodermata: Asteroidea) in the Philippines. Invertebrate Reproduction and Development 56 (DOI:10.1080/07924259.2012.689264).

Bos A.R., B. Mueller & G.S. Gumanao, 2011. Feeding biology and symbiotic relationships of the corallimorpharian Paracorynactis hoplites (Anthozoa: Hexacorallia). Raffles Bulletin of Zoology 59(2): 245-250

Mueller B., A.R. Bos, G. Graf & G.S. Gumanao, 2011. Size-specific locomotion rate and movement pattern of four common Indo-Pacific sea stars (Echinodermata; Asteroidea). Aquatic Biology 12(2): 157-164 (doi:10.3354/ab00326)

Bos A.R., G.S. Gumanao, M.M. van Katwijk, B. Mueller, M.M. Saceda & R.P. Tejada, 2011. Ontogenetic habitat shift, population growth, and burrowing behavior of the Indo-Pacific beach star, Archaster typicus (Echinodermata; Asteroidea). Marine Biology 158(3): 639–648 (DOI 10.1007/s00227-010-1588-0)

 

Click here for Citation details on Google Scholar

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