How red tide poisoned marine life and humans

If unfortunately eating seafood contaminated by red tide, people who are poisoned can suffer from paralysis, diarrhea, memory loss and even death.

According to Science Encyclopedia, red tide is the phenomenon of dyed pink, red, brown, yellow or green seawater due to the temporary increase in the amount of a special flagellated double-celled algae (also called the phenomenon of algae blooms ). Sometimes carrying the plankton or planktonic algae, these Algae-class single-celled organisms move by using a tail-like structure called a whip.

The two-celled protruding algae also photosynthesize and are the same pigments for their photosynthesis to stain water when blooming. They are very popular and widely distributed. In suitable environmental conditions, many species can grow very quickly, creating red tide. Red tide occurs in all waters with warm or mild temperatures.

Scientists do not understand the environmental conditions that promote red tide development. However, this phenomenon is certainly related to the presence of some nutrients, nutrient ratio and water temperature. Red tide is an ancient phenomenon, recorded in the Bible.

Fish died of red tide on a beach in Florida, USA in January 2013.(Photo: Examiner).

Researchers suspect that human activities affect nutrient density in seawater, leading to the frequent occurrence of red tide in some places. In particular, the concentration of nitrogen, phosphorus and other nutrients in seawater increases due to the discharge of fertilizers and animal waste into the sea. Complex changes in global climate also affect red tide. Water used to ballast contributes to two-celled single-celled algae to new waters.

Double-celled dinoflagellates cause red tide to produce toxins. The species associated with toxic red tide are Alexandrium, Dinophysis, and Ptychodiscus . Algae toxins accumulate in marine organisms that feed by filtering large amounts of water, especially bivalve animals such as oysters, clams and oysters. If these bivalve animals are caught when poisoned from red tide, they can poison people to eat.

Sea toxins also affect local ecosystems by poisoning animals. Some toxins, such as Ptychodiscus brevis secretion, red tidal algae in Florida, USA, can exist in the air, irritating the nose and throat.

Red tide also causes great damage to ecosystems when algae die. In some conditions, the decomposition process of massive dead algae mass consumes so much oxygen that it leads to hypoxia in many marine animals, causing them to suffer severe injury or death due to inability to adapt. with an oxygen-deficient environment. Algae also fill up in fish gills or irritate the gills, raising the mortality rate of marine fish.

Saxitoxin is a natural neurotoxin that is synthesized by a number of two flagellates. This substance causes poisoning syndrome that causes muscle paralysis in people who eat seafood. In addition, bipolar monocellular algae also produce toxins that lead to diarrhea. Nitz diatoms secrete domoic acid, causing people to lose their memory.

Marine animals are also affected by algae toxins.

Marine animals are also affected by algae toxins. In 1991, Nitzchia occidentalis diatoms bloom in Monterey Bay, California, accumulating domoic acid in the plankton that feeds on water. As a result, the small fish that eat them are also poisoned and then poison the cormorant and pelicans to eat fish in large quantities.

Another case is the 1988 outbreak of Chrysochromulina polylepis in the Baltic Sea, leading to a widespread death of countless seaweed species, invertebrates and fish. The algae blooms in the Norwegian waters in 1991 killed a large amount of aquaculture salmon. In 1996, red tide killed 149 sea pigs in coastal Florida, USA.

Even big whales die from algae toxins. In 1985, 14 humpback whales died in Cape Cod Bay, Massachusetts, USA, in just 5 weeks. The reason is that whales eat mackerel containing saxitoxin neurotoxins accumulate during the period of algal blooms. When the researchers observed, the whale remained normal after eating, but it died only 90 minutes away.