The Florida Big Bend region in the northeastern Gulf of Mexico contains both spawning sites and nursery habitats for a variety of economically valuable marine species. One species, the gag grouper (Mycteroperca microlepis), relies on the shelf circulation to distribute larvae from shelf-break spawning grounds to coastal seagrass nurseries each spring. Therefore, identifying the dominant circulation features and physical mechanisms that contribute to cross-shore transport during the springtime may provide valuable insight into the variation of the abundance of this reef fish. The physical mechanisms by which cross-shelf movement is possible, and the pathways by which materials may be transported onshore are examined. More specifically, variable wind stress and the conservation of potential vorticity are investigated for their role in setting the net across-shelf transport, using a very high horizontal resolution (800—900 m) numerical ocean model. The simulations demonstrate that the mean springtime shelf circulation is set by the rectification of flow during northwesterly or southeasterly directed wind stress, and significant cross-shelf flow may be generated during winds from the northwest. The springtime flow is mostly barotropic and tends to conserve potential vorticity over time scales shorter than about 12 hrs. For longer time scales, the nonconservation of potential vorticity enables movement of particles inshore. Particle advection experiments demonstrate that a primary pathway exists south of St. George Island by which particles are able to reach the nearshore environment, and that preferred release locations for particles to successfully arrive inshore coincide with known gag spawning aggregation sites. The results provide, for the first time, a description of the mechanisms by which onshore transport is possible from gag spawning sites at the shelf break to seagrass nurseries at the coast. / A Dissertation submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the requirements for the degree of Doctor of
Philosophy. / Spring Semester, 2013. / February 1, 2013. / Coastal physical oceanography, gag grouper, larval transport, Numerical
modeling / Includes bibliographical references. / Eric Chassignet, Professor Directing Dissertation; Mark Bourassa, University Representative; Allan Clarke, Committee Member; Felicia Coleman, Committee Member; William Dewar, Committee Member; Markus Heuttel, Committee Member; Steven Morey, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_183916 |
| Contributors | Todd, Austin C. (authoraut), Chassignet, Eric (professor directing dissertation), Bourassa, Mark (university representative), Clarke, Allan (committee member), Coleman, Felicia (committee member), Dewar, William (committee member), Heuttel, Markus (committee member), Morey, Steven (committee member), Department of Earth, Ocean and Atmospheric Sciences (degree granting department), Florida State University (degree granting institution) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource, computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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