Environmental forensics at sea

Educational value

• The rate of growth of algae in the sea partly depends on the amount of phosphorous and nitrogen compounds available. These compounds are used to fertilise crops and pasture on the land. When they are washed into the sea, some types of algae, bacteria and cyanobacteria can reproduce more quickly. This can change the composition of the kinds of organisms that live in a marine community.
• Some marine environments have a muddy bottom. Among the sediment are the remains of dead plants, animals and bacteria. The deeper sediments are older. By removing a core of mud and examining the dead remains of animals, it is possible to find out how the local environment has changed over time.
• Scientists can use a range of science disciplines to identify the current health of a marine ecosystem. They can use chemistry to find out the chemical composition of the water. By digging core samples from the muddy bottom, they can find out if the animals and plants that have lived in that environment have changed over time. They can use their past knowledge of how some plants and animals respond to environmental change and monitor these organisms into the future to establish likely consequences of human activity on them.
• Food webs are a way of describing the relationships in a community of living organisms. Plants or other producers use sunlight to produce food. All the other organisms including those that eat other animals depend on the producers to start the food-making process. Small changes in an environment can often result in immediate changes in a food web, and longer term can affect many organisms in the food web.

Topics Crops Pollution Marine habitats Scientists Nitrogen cycle Ecosystems Phosphorous cycle Oceans Food webs Nitrogen fertilisers