Marine Ecological Environment Protection "Encyclopedia"
red tide
definition
Red tide: also known as algal bloom, is an ecological anomaly that changes the color of local water bodies caused by the explosive proliferation or high aggregation of certain phytoplankton, protozoa or bacteria in water bodies under specific environmental conditions. Depending on the type and number of red tides, the water will show different colors, such as red or brick red, green, yellow, brown, etc., but some red tides sometimes do not cause discoloration of the seawater.
harm
◆ The biotoxins produced by Red Tide Bio are transmitted to other animals and the human body through the food chain, causing poisoning or even death.
◆ The harm of red tide to the marine ecological environment:
(1) The mucus secreted or produced by the red tide organism adheres to the gills of fish and other marine animals, blocking the respiratory system, resulting in asphyxiation death;
(2) When the red tide organism decays, a large amount of oxygen in the water body is consumed, resulting in hypoxia in the water body or the accumulation of a large amount of hydrogen sulfide and methane, etc., so that the marine organism is hypoxic or poisonous and dies;
(3) A large number of red tide organisms gathered on the surface of seawater, shielding the sun, reducing the transparency of water bodies, and affecting the survival and reproduction of other marine algae and animals that grow in the depths of water bodies;
(4) The competition of red tides for nutrients in water bodies leads to an increase in biomass in water bodies, but a decrease in the number of species;
(5) Red tide causes environmental damage along the beach, causing beach closure, etc.
◆ The impact of red tide on human health, in addition to the feeding of toxins, also includes skin infections caused by physical contact, and the effects of volatile harmful gases on the eyes and respiratory tract.
The harmful pathways of red tide
Human influence on the formation of harmful red tides
Discharge of nutrients: a large amount of industrial and agricultural wastewater, domestic sewage discharge, and the development of aquaculture, etc., resulting in a large number of nutrients imported into the marine environment, the degree of seawater eutrophication is becoming more and more serious, causing frequent red tides;
Introduction of alien species: the development of the maritime industry and the discharge of ballast water can lead to the introduction of alien red tide species, increasing the seed source of red tide;
Changes in population structure: Deterioration of marine water quality and overfishing directly or indirectly affect changes in population structure, leading to the formation of harmful red tides.