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Are diatoms birth control agents in benthic marine ecosystems?

Lookup NU author(s): Dr Gary Caldwell, Emeritus Professor Matt Bentley, Emeritus Professor Peter Olive



The production of toxic short chain aldehydes (SCAs) by pelagic marine diatoms in response to grazing has recently been demonstrated [1, 2]. These wound activated SCAs can regulate copepod population levels by blocking embryonic cleavage leading to abortion or the production of abnormal nauplii. We have demonstrated that water soluble extracts of the diatoms Nitzschia commutata and Skeletonema costatum and the SCA 2-trans, 4-trans decadienal (2,4 DDE) are also toxic to the embryos and larvae of the benthic macroinvertebrates Arenicola marina, Nereis virens, Asterias rubens and Psammechinus miliaris. Exposure to 2,4 DDE at environmentally realistic concentrations (1 ug /ml) results in inhibition of hatching and fertilization success while chronic exposure (0.1 ug /ml) during embryogenesis results in the production of deformed larvae. We have also shown that 2,4 DDE is a potent sperm motility inhibitor and also inhibits oocyte maturation, causing oocytes to undergo apoptosis as they exit prophase arrest of meiosis. In addition, we have extracted and identified 2,4 DDE and other aldehydes from N. commutata. We suggest that diatom-derived SCAs have an important role in regulating the reproductive biology of benthic macroinvertebrates and may play a key role in the evolution of seasonal broadcast spawning strategies. [1] Miralto, A. et al., 1999. The insidious effect of diatoms on copepod reproduction. Nature, 402 (6758): 173-176. [2] Pohnert, G. 2000. Wound-activated chemical defense in unicellular planktonic algae. Angew. Chem. Int. Edit., 39 (23): 4352-+ 2000.

Publication metadata

Author(s): Caldwell GS, Bentley MG, Olive PJW

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Unknown

Conference Name: Functioning of Microphytobenthos in Estuaries

Year of Conference: 2003

Notes: Poster presentation.