Estuaries and Coasts

, Volume 30, Issue 1, pp 102–112

Wind-driven sediment suspension controls light availability in a shallow coastal lagoon

  • S. E. Lawson
  • P. L. Wiberg
  • K. J. McGlathery
  • D. C. Fugate
Article

DOI: 10.1007/BF02782971

Cite this article as:
Lawson, S.E., Wiberg, P.L., McGlathery, K.J. et al. Estuaries and Coasts: J ERF (2007) 30: 102. doi:10.1007/BF02782971

Abstract

Light availability is critically important for primary productivity in coastal systems, yet current research approaches may not be adequate in shallow coastal lagoons. Light attenuation in these systems is typically dominated by suspended sediment, while light attenuation in deeper estuaries is often dominated by phytoplankton. This difference in controls on light attenuation suggests that physical processes may exert a greater influence on light availability in coastal lagoons than in deeper estuaries. Light availability in Hog Island Bay, a shallow coastal lagoon on the eastern shore of Virginia, was determined for a summer and late fall time period with different wind conditions. We combined field measurements and a process-based modeling approach that predicts sediment suspension and light availability from waves and currents to examine both the variability and drivers of light attenuation. Total suspended solids was the only significant predictor of light attenuation in Hog Island Bay. Waves and currents in Hog Island Bay responded strongly to wind forcing, with bottom stresses from wind driven waves dominant for 60% of the modeled area for the late fall period and 24% of the modeled area for the summer period. Higher wind speeds in late fall than in summer caused greater sediment suspension (41 and 3 mg l−1 average, respectively) and lower average (spatial and temporal) downwelling light availability (32% and 55%, respectively). Because of the episodic nature of wind events and the spatially variable nature of sediment suspension, conventional methods of examining light availability, such as fair-weather monitoring or single in situ recorders, do not adequately represent light conditions for benthic plants.

Copyright information

© Estuarine Research Federation 2007

Authors and Affiliations

  • S. E. Lawson
    • 1
  • P. L. Wiberg
    • 1
  • K. J. McGlathery
    • 1
  • D. C. Fugate
    • 2
  1. 1.Department of Environmental SciencesUniversity of VirginiaCharlottesville
  2. 2.Department of Physical ScienceVirginia Institute of Marine ScienceGloucester Point
  3. 3.Department of Marine and Ecological SciencesFlorida Gulf Coast UniversitySouth Fort Myers

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