Physical Properties of Lagoonal Waters at an Atoll 60 Years after Anthropogenic Disturbance
Abstract/Contents
- Abstract
- During the U.S. military occupation of Palmyra Atoll in World War II, large-scale modification of the atoll occurred, including the construction of causeways that formed a ring around the lagoons and divided the lagoons into separate bodies of water. This had a huge impact on the biota of the lagoons, turning coral reefs into rubble. Even after 60 years, no significant recovery has taken place. Changes in flow and circulation are the direct effects of the construction; however, these are difficult to measure directly. Instead, this study surveys the lagoon, both on the surface and at depth, to gather physical data such as temperature, salinity, fluorescence, and light attenuation in order to indirectly draw conclusions about the changes in flow and circulation. Temperatures averaged 28.7 Celcius, with shallower, more enclosed areas averaging up to 31.8 Celcius. Salinity was higher in Eastern and Western Lagoons than in Central Lagoon, suggesting poor mixing with oceanic water and precipitation dominating over evaporation. Fluorescence and light extinction data correlate well, showing a subsurface maximum around 10-15m. Lack of recovery is likely due to changes in flow and circulation rather than directly from elevated temperature or depressed salinity. The temperature and salinity data do indicate that water exchange has decreased with the construction of the causeways. While this change has destroyed previous habitats, it has also created new ones, including possible nursery grounds protected from predators. Now that basic data has been gathered on the characteristics of the water in Palmyra’s lagoons, the likelihood of recovery and the effectiveness of restoration can be studied in greater detail so that Palmyra can continue to be a gem of biodiversity in the Pacific.
Description
| Type of resource | text |
|---|---|
| Date created | June 9, 2003 |
Creators/Contributors
| Author | Chiu, Alice |
|---|
Subjects
| Subject | Palmyra Atoll |
|---|---|
| Subject | lagoons |
| Subject | oceanography |
| Subject | hydrography |
| Subject | temperature |
| Subject | salinity |
| Subject | S-187 |
| Subject | Stanford@SEA |
| Subject | Hopkins Marine Station |
| Subject | Department of Biology |
| Subject | Department of Earth System Science |
| Subject | BIOHOPK 182H |
| Subject | BIOHOPK 323H |
| Subject | EARTHSYS 323 |
| Subject | ESS 323 |
| Genre | Student project report |
Bibliographic information
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- This work is licensed under a Creative Commons Attribution 3.0 Unported license (CC BY).
Preferred citation
- Preferred Citation
- Chiu, Alice, 2003. Physical Properties of Lagoonal Waters at an Atoll 60 Years after Anthropogenic Disturbance. Unpublished student research paper, S-187, Stanford@SEA, Stanford Digital Repository. https://purl.stanford.edu/hm991rt5124.
Collection
Stanford@SEA -- Student papers
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