Often found along a marine coast with its deep red or brown in colour, red tide is a phenomenon when harmful colonies of microscopic algaes are supplied with excess nutrients, multiplied uncontrollably, and become an unwanted mass commonly called “red tide” that produces toxic and causes harmful effects on people and marine life. The human illnesses cause by these algaes can be fatal but rare.
Red tide usually occurs in spring and s ummer season when ocean conditions are best for algae growth. There are different types of toxic algae that causes this phenomenon such as Karenia brevis (K. brevis), Alexandrium catanella, Alexandrium fundyense and Pseudonitzchia.
Not only do red tides causes a temporarily toxic oceans that kills fish and make shellfish dangerous to eat, but they also deplete the dissolve oxygen in the ocean thus creating a dead zone. This happens when the toxic algae die, it will sink on the bottom of the ocean and become food for microbes. These microbes require oxygen to multiply and leaves little oxygen available for other marine life to breathe. Massive fishes’ dies leaving the ocean surface covered in floating dead fish.
