Coral Reefs

, Volume 25, Issue 1, pp 23–36

The effect of water exchange on bacterioplankton depletion and inorganic nutrient dynamics in coral reef cavities

Authors

    • Royal Netherlands Institute for Sea Research
  • S. R. Scheffers
    • Royal Netherlands Institute for Sea Research
    • Carmabi Ecological Institute, Piscadera Bay
  • F. I. M. Thomas
    • University of South Florida
  • M. Driscoll
    • University of South Florida
Report

DOI: 10.1007/s00338-005-0066-5

Cite this article as:
van Duyl, F.C., Scheffers, S.R., Thomas, F.I.M. et al. Coral Reefs (2006) 25: 23. doi:10.1007/s00338-005-0066-5

Abstract

We studied the effect of water exchange on the depletion (or accumulation) of bacterioplankton, dissolved organic matter and inorganic nutrients in small open framework cavities (50–70 l) at 15 m depth on the coral reef along Curaçao, Netherlands Antilles. The bacterioplankton removal rate in cavities increased with increasing water exchange rates up to a threshold of 0.0045 s−1, reaching values of 50–100 mg C m−2 total interior cavity surface area (CSA) per day. Beyond the threshold, bacterioplankton removal dropped. The cryptic community is apparently adapted to the average water exchange in these cavities (0.0041 s−1). Dissolved inorganic nitrogen (DIN), nitrate + nitrite (NO x ) in particular, accumulated in cavity water and the accumulation decreased with increasing water exchange. Net NO x effluxes exceeded net DIN effluxes from cavities (average efflux rate of 1.9 mmol NO x vs. 0.8 mmol DIN m−2 interior CSA per day). The difference is ascribed to net ammonium losses (NH4) in cavities at reef concentrations >0.025 μM NH4, possibly due to enhanced nitrification. Dissolved inorganic phosphate accumulated in cavities, but was not related to water exchange. The cryptic biota in cavities depend on water exchange for optimization of consumption of bacterioplankton and removal of inorganic nitrogen. Coral cavities are an evident sink of bacterioplankton and a source of NO x and PO 4 3− .

Keywords

Coral cavity Water exchange coefficient Bacterioplankton removal Nutrient regeneration DOC Cryptic biota

Copyright information

© Springer-Verlag 2005