Algae on Water Supplies

　　The Impact of Algae on Aquatic Resources

　　In general, the consensus leans towards a positive impact, albeit with nuanced implications. Algae and cyanobacteria are minute organisms native to both marine and freshwater ecosystems. Usually visible only under the microscope, some species form colonies visible to the naked eye. Understanding the similarities and differences between algae and cyanobacteria is vital as both significantly influence the quality of surface water. Algae contribute positively by releasing oxygen during their metabolic processes, thereby oxygenating the water. While green algae are renowned for their oxygen production, blue-green algae tend to float on the water’s surface and are associated with water quality degradation. Algae are integral to the aquatic food chain, providing essential nutrients for zooplankton and small fish, which in turn become food for larger fish and wildlife. An increase in algae within water bodies indicates enhanced sequestration of atmospheric carbon dioxide and oxygen release. Algae flourish in warm, sunny conditions with ample nutrients, commonly inhabiting the top 60-90 meters of ocean water within the oxygen-rich, sunlight-penetrated epipelagic zone, which is warmer than deeper layers.

　　Algae found in certain water bodies also have another beneficial aspect. They act as reliable indicators of a water body’s trophic state, revealing pollution levels and nutrient content. A lake dominated by green algae and diatoms is typically clean and oligotrophic, whereas excessive blooms of blue-green algae signal a more polluted, eutrophic state, often linked to problematic Cyanobacteria.

　　Cyanobacteria are classified as eubacteria or true bacteria. Historically, they were considered blue-green algae rather than bacteria. All bacteria are prokaryotes, meaning they lack an organized nucleus. Cyanobacteria are classified as bacteria because their genetic material is not enclosed in a membrane-bound nucleus. Unlike other bacteria, they contain chlorophyll and utilize solar energy. The term ‘blue-green’ comes from the initial identification of bluish-green cyanobacteria, but the group includes various colors like olive, dark green, and purplish hues.

　　Cyanobacteria are naturally found in surface waters and can experience blooms under favorable conditions, leading to visible aggregates that may dominate water bodies, even blocking parts of streams or rivers. Bloom occurrences are unpredictable, with some species blooming in spring and others more often in autumn. These organisms can thrive in both flowing and stagnant water and may bloom under ice in winter. Algae frozen in ice are released during thawing, becoming a vital food source for krill and similar organisms. Bloom formation is often linked to prolonged hot, calm periods with elevated water temperatures and nutrient levels, especially phosphorus, which come from runoff or leaching from fertilized lands, improperly managed manure, stormwater discharges, or soil erosion. These nutrients fuel blooms more significantly in coastal waters than in the open ocean, where blooms are generally harmless and beneficial due to the ocean’s relative nutrient scarcity.

　　Massive algal and cyanobacterial blooms can clog intake pipes and filtration systems, causing functional and aesthetic issues. During blooms, water may contain millions of algae per liter. As these blooms die and decompose, they can cause unpleasant odors due to oxygen depletion in the surrounding water. In ponds or shallow lakes, such decay can lead to severe oxygen deficits and fish mortality. While algae are not inherently toxic to humans or animals, some cyanobacteria produce potent cyanotoxins, which can cause serious illness or death if ingested. With over 70 identified cyanotoxins, it’s impossible to determine toxicity visually; therefore, it’s wise to assume toxins are present and to avoid contaminated water.

　　Algae are a natural and generally beneficial component of aquatic ecosystems, improving water quality, supporting aquatic life, and even benefiting humans. However, the unchecked growth of certain algae under optimal conditions can lead to water quality concerns. In such cases, the saying that too much of a good thing can be bad rings true. Balance is crucial, and the right equilibrium fosters a stable and thriving environment. Aim for balance!