Circulation, residence time and retention in a tropical coral reef
Abstract/Contents
- Abstract
- We perform a study of residence time and circulation on the tropical fringing reef on the north shore of Moorea, French Polynesia. This study was motivated by the dependence of many important biological factors on residence time, notably, phytoplankton biomass, nutrient availability and larval recruitment. Three important features that are common to fringing reef systems were identified as important to residence time: 1) the strength of wave-driven flow 2) the dynamics of a jet exiting the reef pass and 3) thermal buoyancy-driven exchange. Through field observations we determine that wave-driven flow is responsible for the majority of the volume flow through the system. Our analysis of the field observations shows that water exiting through the reef passes was often re-entrained by the wave driven flow; this provides an important retention mechanism for reef water. The amount of water retained by a wide reef pass was investigated with field measurements and a simplified numerical model of the field site. We find that alongshore flow, jet strength, jet buoyancy and jet to reef area ratios are all important factors influencing retention. In normal winter field conditions, the amount of water re-entrained ranged from 20- 50 percent of exiting water. Additionally, we find that the exchange in the back bay of the system is primarily determined by variations in depth that create horizontal thermal and therefore buoyancy gradients. The horizontal buoyancy gradients are an important mechanism for exchange in parts of the reef less affected by the wave-driven circulation. The difference in heating between the reef and the ocean also maintains a stratified exchange flow in the pass; the dynamics that determine the interface and mixing at the jet are controlled by this thermal stratification.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Herdman, Liv Muir Meltzner |
|---|---|
| Associated with | Stanford University, Civil & Environmental Engineering Department |
| Primary advisor | Monismith, Stephen Gene |
| Thesis advisor | Monismith, Stephen Gene |
| Thesis advisor | Fringer, Oliver B. (Oliver Bartlett) |
| Thesis advisor | Hench, James Lawrence |
| Thesis advisor | Koseff, Jeffrey Russell |
| Advisor | Fringer, Oliver B. (Oliver Bartlett) |
| Advisor | Hench, James Lawrence |
| Advisor | Koseff, Jeffrey Russell |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Liv Muir Meltzner Herdman. |
|---|---|
| Note | Submitted to the Department of Civil and Environmental Engineering. |
| Thesis | Ph.D. Stanford University 2012 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Liv M. Herdman
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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