|Densities of protozoan nanoplankton populations in interdital mesocosms: influence of oil pollution and a self-igniting cleaning agent|
Bak, R.P.M.; Nieuwland, G. (1987). Densities of protozoan nanoplankton populations in interdital mesocosms: influence of oil pollution and a self-igniting cleaning agent. Neth. J. Sea Res. 21(4): 303-315
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579, more
|Authors|| || Top |
- Bak, R.P.M.
- Nieuwland, G.
Population densities of small pelagic protists (< 50 µm) were studied in intertidal mesocosms. The mesocosms represented tidal flats of the adjacent Wadden Sea under 3 sets of environmental conditions: control, oil spill (F3), and oil spill treated with a new type of cleaning agent (granular, self-igniting). There were obvious effects, such as the almost complete elimination of ciliates and the reduced filtering by macrozoobenthos, upon the introduction of the pollutants in the experimental conditions. Within 3 days, heterotrophic flagellate densities increased exponentially (0.1 to 0.3 μ·h-1, max. 17·10³·cm-3) to return to pre-oil spill levels in two weeks (2 to 3·10³·cm-3). Maximum densities of heterotrophic flagellates corresponded with a period of low bacterial numbers, suggesting that trophic coupling exists during the inactivity of filter feeders. Such a pattern did not exist for the autotrophic nanoplankton. The effects of the oil plus cleaning agent treatment were more pronounced than the effect of oil. The absence of fluctuations in population densities in the control mesocosm and the emergence of such fluctuation patterns under experimental conditions, with reduced activity of benthic filter feeders, indicate that predation by the benthic fauna is a structuring factor for the heterotrophic nanoplankton in such intertidal systems.