Use your knowledge of NPP to explain why freshwater marshes have a high CUE and the advantage of this.

Do not refer to abiotic factors in your answer.

Explanation ______________

Advantage ______________

Freshwater marsh soils are normally waterlogged. This creates anaerobic conditions.

Use your knowledge of the nitrogen cycle to suggest why these soils contain relatively high concentrations of ammonium compounds and low concentrations of nitrite ions and nitrate ions.

A student investigated the growth rate of a freshwater marsh plant.

The growth rate (R) of a plant can be determined using this equation.

R = (ln W2 − ln W1) / t

Where

ln = natural logarithm

t = duration of the investigation in days

W1 = plant biomass at the start of the investigation

W2 = plant biomass at the end of the investigation

The student used the equation above; however, she substituted height for biomass. This was because she did not want to destroy the plants to measure their biomass.

State the assumption the student has made and suggest why this assumption might not be valid.

At the end of the investigation, the student noted the freshwater marsh plant had grown 268 mm in height, and now measured 387 mm. She calculated the rate of growth (R) to be 0.097 mm m−1 day−1

Use this information and, substituting height for biomass, use the equation to calculate the duration of the student's investigation.

Give your answer to the nearest full day.

Show your working.

Answer ______________ days