Inorganic selenium bioaccumulates more readily in phytoplankton than zooplankton. Primary producers are plants, phytoplankton and zooplankton that require photosynthesis. Predation by Mysis has shifted zooplankton and phytoplankton community size structure. Plankton includes bacteria, plants (phytoplankton) and animals (zooplankton) that drift in the sea. Both phytoplankton and zooplankton are found in the lake. Chlorophyll are photosynthetic pigments that are often used as an indicator of phytoplankton biomass. Another example of this is in phytoplankton and zooplankton. Spring produces blooms of swarming phytoplankton which provide food for copepods. Phytoplankton and macroalgae present in the water mass-produce oxygen by way of photosynthesis. Thus there is the element of synergism between phytoplankton and heterotrophic bacteria. Bacteria absorb dissolved organic matter containing minerals as they scavenge phytoplankton blooms. Places where chlorophyll concentrations were high, meaning many phytoplankton were growing, are yellow. Increases of nutrient iron results in blooming of phytoplankton. Estimates of oceanic phytoplankton change are highly variable. Places where chlorophyll amounts were very low, indicating very low numbers of phytoplankton, are blue.