What are the control methods of red tide?

Red tide, also known as red tide algae, is also known as "harmful algae" or "red ghost" internationally. It is a harmful ecological phenomenon that some phytoplankton, protozoa or bacteria in seawater proliferate explosively or gather highly under certain environmental conditions, resulting in discoloration of water. Red tides are not always red, mainly including water blooms in fresh water systems, general red tides in the ocean, brown tides and green tides newly defined in recent years, etc.

Red tide is an abnormal phenomenon in marine ecosystem. It is caused by the explosive reproduction of red tide algae in the algae family under specific environmental conditions. Seaweed is a big family. Except for some large algae, many of them are very tiny plants, and some are single-celled organisms. According to the species and quantity of organisms that cause red tides, seawater sometimes presents different colors, such as yellow, green and brown.

The occurrence of red tide is closely related to marine pollution. Industrial sewage and urban domestic sewage carrying all kinds of organic and inorganic nutrients are discharged into the sea in large quantities, which leads to eutrophication in the sea area, which is the root cause of red tide. If the seawater contains a certain amount of trace elements such as iron and cobalt, it is easy to produce red tides under natural conditions such as temperature, salinity and light.

Cause (1) Natural cause: high temperature; Still water; Quiet wind; The sea area is relatively closed. (2) Human factors: the coastal areas are densely populated and economically developed, and a large amount of industrial and domestic sewage is discharged into the sea; A large number of fertilizers and pesticides are used in agricultural production; Due to the high degree of marine development and the expansion of aquaculture scale, the aquaculture waters are seriously polluted. The important reason-biological factors-the proliferation and aggregation of red tide organisms such as marine ephemera microalgae.

First of all, the occurrence of red tide destroys the normal ecological structure of the ocean, thus destroying the normal production process in the ocean, thus threatening the survival of marine life. Secondly, some red tide organisms secrete mucus and attach to the gills of fish, shrimp, shellfish and other organisms, which damages breathing and leads to suffocation and death. Toxic red tide organisms will cause poisoning death after being eaten by marine organisms. Human consumption of seafood containing toxins will have similar consequences. Thirdly, after a large number of red tide organisms die, the dissolved oxygen in seawater will be consumed during the decomposition of the remains, resulting in an anoxic environment, resulting in a large number of deaths of fish, shrimp and shellfish.

In the early stage of plant red tide, due to the photosynthesis of plants, the water body will have high chlorophyll a, high dissolved oxygen and high chemical oxygen consumption. This change in environmental factors makes some marine organisms unable to grow, develop and reproduce normally, leading to some organisms escaping or even dying, thus destroying the original ecological balance.

Some red tide organisms secrete red tide toxins. Fish and shellfish will not be poisoned in toxic red tide areas, but biological toxins will accumulate in the body, and their content greatly exceeds the acceptable level for human consumption. If these fish, shrimp and shellfish are eaten carelessly, they will cause human poisoning and even death in serious cases.

The destruction of marine fishery and aquatic resources (1) destroyed the erbium base of fishing grounds, resulting in the decline of fishery output. (2) The abnormal occurrence and reproduction of red tide organisms will lead to mechanical blockage of the valves of economic organisms such as fish, shrimp and shellfish, which will lead to suffocation and death of these organisms. (3) In the later period of red tide, a large number of red tide organisms die, which can cause serious environmental hypoxia or produce harmful substances such as hydrogen sulfide under the action of bacterial decomposition, so that marine organisms die of hypoxia or poisoning. (4) Some red tides contain biological toxins, which can directly kill fish, shrimp, shellfish and other organisms. Harm of red tide to human health

How to prevent it? 1. Control the eutrophication of the sea area: (1) Pay attention to the treatment of urban sewage and industrial sewage, and improve the sewage purification rate. (2) Rational development of mariculture. 2. Artificial improvement of water body: For example, in eutrophic inland sea or shallow sea, breeding large economic algae such as kelp fence can not only purify water body, but also have high economic benefits; Use the energy of natural tides to improve the exchange capacity of water bodies; Dredger and suction dredger can be used to remove polluted sediments. 3. Control the introduction of exotic species of toxic red tide organisms. 4. Perfect rules, regulations and measures should be formulated to prevent toxic red tide organisms from being transplanted to the culture area by ships and breeding varieties.