Algae Bloom on Spui River

Goudswaard, Netherlands

Algae bloom on Spui River, a small tidal estuary connecting the river Oude Maas and the Haringvliet estuary. Storm surge barriers have changed this region from an active estuary to stagnant. Blooms occur in calm, unusually warm waters with excess nutrients which typically come from sewerage, fertilizer runoff or animal waste from factory farms. Different algae form in salt versus fresh water, and some are more toxic than others. They all seem to cause a “hypoxic” conditions, depleting all oxygen in the water, thus killing everything else.