Modeling and observations of high-frequency flow variability and internal waves at a Caribbean reef spawning aggregation site

Ezer, Tal and Heyman, William D. and Houser, Chris and Kjerfve, Björn (2011) Modeling and observations of high-frequency flow variability and internal waves at a Caribbean reef spawning aggregation site. Technical Report.

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    Abstract

    The characteristics and forcing mechanisms of high-frequency flow variations (periods of minutes to days) were investigated near Gladden Spit, a reef promontory off the coast of Belize. Direct field observations and a high resolution (50-m grid size) numerical ocean model are used to describe the flow variations that impact the initial dispersion of eggs and larvae from this site, which serves as a spawning aggregation site for many species of reef fishes. Idealized sensitivity model experiments isolate the role of various processes, such as internal waves, wind, tides, and large-scale flow variations. The acute horizontal curvature and steep topography of the reef intensify the flow, create small-scale convergence and divergence zones, and excite high-frequency oscillations and internal waves Although the tides in this area are relatively small (∼10-cm amplitude), the model simulations show that tides can excite significant high-frequency flow variations near the reef, which suggests that the preference of fish to aggregate and spawn in the days following the time of full moon may not be coincidental. Even small variations in remote flows (2–5 cm s−1) due to say, meso-scale eddies, are enough to excite near-reef oscillations. Model simulations and the observations further suggest that the spawning site at the tip of the reef provides initial strong dispersion for eggs, but then the combined influence of the along-isobath flow and the westward wind will transport the eggs and larvae downstream of Gladden Spit toward less turbulent region, which may contribute to enhanced larval survival.

    Item Type: Technical Reports (Technical Report)
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      Unique ID or DOI: 1007/s10236-010-0367-2
      Publisher: Springer-Verlag 2011
      Keywords: Numerical modeling . Internal waves Reef promontory Spawning aggregation Turbulence
      Subjects: (C) Ecosystems > (CB) Marine > (CBA) Coral Reefs
      Publication Sources: (3) Other Source > (3D) Other or Unspecified
      Date Deposited: 30 Sep 2013 10:20
      Last Modified: 30 Sep 2013 10:20
      URI: http://eprints.uberibz.org/id/eprint/1369

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