You are asked to estimate the nutrient content of a lake and its possible effect on net primary productivity. What data will you collect to determine the effect?

1. Sample water from different parts of the lake and determine nutrient composition.
2. Sample the carbon content of the phytoplankton growing.
3. Take sample of lake water and artificially enrich it, then see the effect of the enrichment on phytoplankton growth compared with growth in unenriched lake water.
4. Wait for spring turnover to check for nutrients found in the lake floor.

Answer:

a) sampling water from different part of lakes wont determine the exact carbon content and organic matter this option may mislead observation.

b) the best way to estimate the nutrient content is by measuring the carbon content of the phytoplankton growing

c) but in order to see the effect of nutrients on net primary productivity a comparative study is required which may be possibly the third option (C).

d) waiting for spring turnover may result in changes in concentration of nutrients over time which would again mislead observations

basically nutrient enrichment leads to increase in the net primary productivity upto certain level because of increase in organic matter , later on eutrophication takes place which may lead to hypoxic condition and death of life underwater. this ultimately leads to death of lake.