Indicator protocols: Total nitrogen + flow leaving a sub-catchment or whole catchment 2008-08-12T01:17:05Z 2008-09-04T06:23:01Z Indicator protocols: Total nitrogen + flow leaving a sub-catchment or whole catchment Nutrients in aquatic environments: nitrogen National Land and Water Resources Audit National Land and Water Resources Audit <p>Nitrogen is an essential element required by animals and plants. However, high levels of nitrogen can also be an important contributor to eutrophication - especially in estuarine and marine waterways. Symptoms of eutrophication may include algal blooms and seagrass decline.</p> PN21557 PN21557