Farmland run-off into estuaries

Educational value

• Modern farming practices are not only having an effect on land environments, they can be detrimental to coastal areas. Deforestation and increased fertiliser use are contributing to higher levels of nutrients and contaminants entering waterways from the land. Changes to the way the land is used is having consequences on coastal environments and for the organisms that live there.
• The 'run-off' of nutrients from the land into coastal waters can have positive and negative effects on the environment. As estuarine nutrient levels increase, so does the growth of plants such as seaweeds, which play a vital role in marine ecosystems. However, there is a threshold above which nutrient increases can be tolerated, resulting in negative effects on the ecosystems.
• When there is a change in nutrient or contamination levels in a marine environment, it can have far-reaching consequences for marine food webs. For instance, nutrient changes can influence the growth of primary producers, such as seaweed. This change can directly and indirectly influence many other organisms in the food web.
• Dr Candida Savage is a marine biologist with an interest in human impacts on New Zealand's coastal environments. Her research includes studying how run-off from the land affects marine ecology. Dr Savage teaches marine science at the University of Otago, New Zealand.

Year level

5; 6; 7; 8; 9

Topics Farming systems Scientific inquiry Food webs Human impact Estuaries Marine biologists