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Among these species, some comes out as a harmful breed for other aquatic animals and human who comes in contact with them because they release toxins which disables certain aquatic lives to breathe or can be dangerous because of their accumulated biomass. These harmful algal blooms are formerly known as “red tides”, because many were found composed of dinoflagellates with red pigments, which cause discoloration of water in red, but can also discolor water into brown or green. Algal blooms refer to a large concentration of marine microorganism and they get harmful when they start excreting poisonous toxins and become as a contributing factor in hundreds of mortalities of aquatic mammals, fishes, birds and other marine and coastal species which happens at the exposure of a potent neurotoxins.
Excretion of toxins can result in deaths of a large number of aquatic species. Harmful Algal Blooms also put a negative impact on natural beauty and have bad odors produced by the decaying of biomass. Theory Researchers and investigation teams are still unable to know the root cause and it is still controversial. Some theories are underlined, for explaining some of the causes that might be the reason of such dangerous Algal Blooms, threatening millions of aqua marine lives. It is believed that toxin blooms are often in result of one or more species of Cyanobacteria which are blue and green algae and grow on nutrient pollution.
These spread during warm season of the year and produces both green (chlorophyll) and blue (phycocyanin) which appears as blue and green discoloration of water. It was previously referred as Red Tides, but with the passage of time, things got clear that these harmful algal blooms are not associated with the movement of tides and can vary in color from red to brown, green and blue, therefore they are now known as HABS (Harmful Algal Blooms). They are dangerous because of their toxins or the manner in which the physical structure of the cell affect co occurring species and alter food web process.
It can be extremely dangerous when the water is clear with low concentration of cell in the presence of toxic HABs. Micro or Macro-algae is termed for seaweeds as well which sometimes out grows and causes serious ecological problems like habitat alteration, indigenous species and lowers oxygen level in deep water. Moreover, some HABs are not algae but small animals, who do not grow with photosynthesis but get their nutrition by grazing. A continuous research is going on since decades to get to the root cause of harmful algal blooms.
Things are getting clear with the study but root issues are still inapproachable. Contributing Factors A study was carried out to find out the factors that contribute in the massive growth of harmful Algal Blooms. In some coastal regions, they appeared to be completely natural with a seasonal coastal upwelling and with the movement of ocean currents but in some areas, it is noticed that human activities are helping them grow massively. They are getting nutrition through human loading. Coastal pollution is the biggest factor, helping HABs to develop at large scale through systematic increase in water temperature and human waste disposal.
Iron rich dust influx from large deserts can highly promote the cause of HABs. It is still unclear that what initiates this dangerous algae but research is still going on to reach the root issue. They grow quickly with an abundance of nitrates and phosphates which gets to coastal areas through agricultural run outs or storm water runs, coinciding with warmth which ultimately provide the best atmosphere to grow. Once the bloom is initiated it travels or spread hundreds or thousands of kilometers through coastal currents by wind deviation.
Threats It
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