httpwwwmhhecombioscigenbiotlw3virtuallabslab29overviewpdf Do

http://www.mhhe.com/biosci/genbio/tlw3/virtual_labs/lab29/overview.pdf

Does diesel fuel contamination affect meiofauna consumption of microalgae?

Hypothesis: Diesel contamination affects higher trophic levels in the benthic environment by reducing the number of meiofauna feeding microalgae.

Here is the answer that I need help with:

Why is the second experiment so important for understanding the effects of contamination on the benthic community?

Solution

Yes, diesel fuel contamination affects meiofauna consumption of microalgae.

Explanation: In the first experiment, it was observed that due to diesel contamination, the microalgae population increased. So, it was concluded that microalgae are benefited by diesel contamination.

In the second experiment, it was found out that that diesel contamination is actually affecting the marine food chain/web; which in turn, is responsible for rise in microalgae biomass. In the food chain,

Zooplanktons (over here meiofauna) ---feed on----> phytoplanktons (microalgae)

Now, if zooplanktons stop feeding on phytoplankton, then automatically the phytoplankton population will rise. This is what has happened here. The marine meiofauna is unable to feed on microalgae contaminated with diesel. So, it is the decreased meiofaunal grazing that is responsible for increase in micro algal biomass. Therefore, second experiment is important. Please note that if second experiment had not been conducted, then there would be a misinterpretation in results (that has arisen as a result of first experiment).