Submerged Spirogyra (green algae) Floating mass of Spirogyra and Mougeotia (green algae) Accumulation of pine pollen off Grand Isle Accumulation of pine pollen Submerged Spirogyra (green algae) Floating clumps of Ulothrix (green algae) Green Algae Shoreline accumulations of Spirogyra (green algae) Floating clumps of Ulothrix (green algae) Accumulation of pine pollen Accumulation of pine pollen Green Algae December 28, 2016 Not all scum in the water is cyanobacteria or blue-green algae.