User:Gggg2123/New sandbox

Bloom Characterization
The term "algal bloom" is defined a bit inconsistently depending on the scientific field and can range between a "minibloom" of harmless algae to a large, harmful bloom event. Since 'algae' is a broad term including organisms of widely varying sizes, growth rates, and nutrient requirements, there is no officially recognized threshold level as to what is defined as a bloom. Because there is no scientific consensus, blooms can be characterized and quantified in several ways: measurements of new algal biomass, concentration of photosynthetic pigment, quantification of the bloom's negative effect, or relative concentration of the algae compared to the rest of the microbial community. For example, definitions of blooms have included when the concentration of chlorophyll exceeds 100 mg/L, when the concentration of chlorophyll exceeds 5 ug/L, when the species considered to be blooming exceeds concentrations of 1000 cells/mL, and when the algae species concentration simply deviates from its normal growth. It is worth noting that this list is not exhaustive, many other definitions of algal bloom exist.

Blooms are the result of a nutrient that the particular algae need being introduced to the local aquatic system. This growth-limiting nutrient is typically nitrogen or phosphorus, but can also be iron, vitamins, or amino acids. There are several mechanisms for the addition of these nutrients in water. In the open ocean and along coastlines, upwelling from both winds and topographical ocean floor features can draw nutrients to the photic, or sunlit zone of the ocean. Along coastal regions and in freshwater systems, agricultural, city, and sewage runoff can cause algal blooms. Two classic examples of anthropogenic algal blooms in the United States are in Lake Erie and the Gulf of Mexico.

Algal blooms, especially large algal bloom events, can reduce the transparency of the water and can discolor the water. The photosynthetic pigments in the algal cells, like chlorophyll and photoprotective pigments, determine the color of the algal bloom. Depending on the organism, its pigments, and the depth in the water column, algal blooms can be green, red, brown, golden, and purple. Bright green blooms in freshwater systems are frequently a result of cyanobacteria (colloquially known as "blue-green algae") such as Microcystis. Blooms may also consist of macroalgal (non-phytoplanktonic) species. These blooms are recognizable by large blades of algae that may wash up onto the shoreline.

Of particular note are the rare harmful algal blooms (HABs), which are algal bloom events involving toxic or otherwise harmful phytoplankton. There are many species that can cause harmful algal blooms. For example, Gymnodinium nagasakiense can cause harmful red tides, dinoflagellates Gonyaulax polygramma can cause oxygen depletion and result in large fish kills, cyanobacteria Microcystis aeruginosa can make poisonous toxins, and diatom Chaetoceros convolutus can damage fish gills.


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Once the nutrient is present in the water, the algae begin to grow at a much faster rate than usual. In a minibloom, this fast growth benefits the whole ecosystem by providing food and nutrients for other organisms. In harmful algal blooms,

-types of algal blooms (HAB, red tide, coastal ocean, freshwater, "minibloom", natural seasonal nutrient loading fluctuations)

-what are the general effects of algal blooms (benign, HAB)