For the first time, NIWA has used satellite images to monitor the health of coastal waters around Aotearoa by tracking levels of suspended sediment in those waters. Satellite data has already been used to monitor algal blooms, oil spills and water temperature, NIWA said. Now, NIWA has analysed images from NASA's Aqua MODIS satellite which images the entire Earth's surface every two or three days to measure changes in suspended sediment - or total suspended solids (TSS) - in New Zealand's coastal waters. TSS contains a range of material such as mud, silt and microalgae which in high concentrations can cause problems for estuaries, coasts and oceans, and aquatic life. Scientists looked at more than 20 years of monthly satellite images of New Zealand's coasts and found that generally, the concentration of TSS was increasing in the South Island and decreasing in North Island waters. High TSS can affect the ability of marine life, such as little blue penguins, to catch food. NIWA said it can also block light from reaching underwater plants and is associated with elevated levels of pathogens, nutrients and pollutants.
