Mass mortality of the West Indian echinoid diadema antillarum: a natural experiment in taphonomy
During 1983, populations of the common long-spined echinoid Diadema antillarum were decimated by disease throughout the West Indies. Depending on the degree of recovery, this mass mortality could have profound effects on the coral reef ecosystem. The role of D. antillarum as a grazer of algae and agent of bioerosion is well documented. The hypothesis that the sudden incorporation of tests and spines of innumerable urchins into the reef sediments would leave a clear record of the mortality event was tested at Bonaire, Netherlands Antilles, where the mortality was witnessed in November, 1983. By August, 1984, there were every few live D. antillarum, no intact empty tests, but abundant broken up spines in the superficial sediments of the leeward fringing reefs. Sediment samples taken along a series of profiles from 6-36 m depth were analyzed for total echinoderm content and contribution of D. antillarum material. The echinoderm fraction shows a slight increase over pre-mortality levels as reported by Kobluk and Lysenko (1984), but it is not yet clear that this resulted from an increase in D. antillarum. Samples taken from cores 30 cm below the sediment surface show echinoderm fractions equal to or greater than surficial samples, suggesting that bioturbation and turbulence have rapidly disseminated any sharp record of the event. The lack of a strong signal of this event demonstrates the inadequacy of the reef sedimentary record to record many short-term although ecologically significant perturbations.
- Research Organization:
- Univ. of Cincinnati, OH (USA)
- OSTI ID:
- 6577677
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ECHINODERMS
DISEASES
FOOD CHAINS
PREDATOR-PREY INTERACTIONS
WEST INDIES
AQUATIC ECOSYSTEMS
BIOLOGICAL EFFECTS
DRILL CORES
MORTALITY
PALEONTOLOGY
POPULATION DYNAMICS
REEFS
SEDIMENTS
ANIMALS
AQUATIC ORGANISMS
ECOSYSTEMS
GEOLOGIC STRUCTURES
INVERTEBRATES
ISLANDS
580100* - Geology & Hydrology- (-1989)
550000 - Biomedical Sciences
Basic Studies