Some Effects of Tributyl Tin (TBT) on Marine Algae

Trials were carried out during 1986 on the effects of two concentrations of tributyl tin (TBT) (low level gl^-1TBT; high level gl^-1(TBT) on chlorophyll-a production by benthic microalgae in sandy substrate microcosms populated with a range of invertebrate species. Highest chlorophyll-a levels were found in the high TBT microcosms. Virtually no animals survived in these microcosms which meant that algal production was not limited by grazing. A greater biomass of grazing animals was present in the controls compared to the low TBT microcosms. In spite of this, chlorophyll-a levels were higher in the controls and we conclude that growth of benthic microalgae was reduced in the low TBT microcosms. Also during 1986, preliminary studies were made on changes in concentration of dissolved oxygen due to respiration and photosynthesis in Pavlova lutheri and Ulva lactuca treated with gl^-1and gl^-1TBT. Respiration increased significantly in both species due to the effect of TBT but photosynthesis results were complicated by a significant effect of acetic acid, the carrier used to introduce TBT into solution. The results are discussed in relation to the possible metabolic mode of action of TBT.