IMIS | Lifewatch regional portal

You are here

IMIS

[ report an error in this record ]basket (0): add | show Print this page

The influence of pore-water advection, benthic photosynthesis, and respiration on calcium carbonate dynamics in reef sands
Rao, A.M.F.; Polerecky, L.; Ionescu, D.; Meysman, F.J.R.; de-Beer, D. (2012). The influence of pore-water advection, benthic photosynthesis, and respiration on calcium carbonate dynamics in reef sands. Limnol. Oceanogr. 57(3): 809-825. dx.doi.org/10.4319/lo.2012.57.3.0809
In: Limnology and Oceanography. American Society of Limnology and Oceanography: Waco, Tex., etc. ISSN 0024-3590; e-ISSN 1939-5590, more
Peer reviewed article  

Available in  Authors 

Keyword
    Marine/Coastal

Authors  Top 
  • Rao, A.M.F., more
  • Polerecky, L.
  • Ionescu, D.
  • Meysman, F.J.R., more
  • de-Beer, D.

Abstract
    To investigate diel calcium carbonate (CaCO3) dynamics in permeable coral reef sands, we measured pore-water profiles and fluxes of oxygen (O2), nutrients, pH, calcium (Ca2+), and alkalinity (TA) across the sediment-water interface in sands of different permeability at Heron Reef, Australia. Background flushing rates were high, most likely as a result of infaunal burrow irrigation, but flux chamber stirring enhanced pore-water exchange. Light and pore-water advection fueled high rates of benthic primary production and calcification in sunlit surface sediments. In the light, benthic photosynthesis and calcification induced surface minima in Ca2+ and TA and peaks in pH and O2. Oxygen penetration depth in coarse sands decreased from ~ 1.2 cm during the day to ~ 0.6 cm at night. Total oxygen uptake (TOU) in dark chambers was three to fourteen times greater than diffusive uptake and showed a direct effect of pore-water advection. Greater sediment oxygen consumption rates were observed in higher permeability sands. In the dark, TA release was not stimulated by increasing TOU because of a damping effect of pore-water advection on metabolic CaCO3 dissolution efficiency. On a daily basis, CaCO3 undergoes net dissolution in Heron Reef sands. However, pore-water advection can reverse the CaCO3 budget and promote CaCO3 preservation under the most energetic conditions.

All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy Top | Authors