Davies O. A., Ogidiaka E., Nwose F. A.
Blooms of autotrophic algae and some heterotrophic protists are increasingly frequent in coastal and inland waters in Nigeria and around the world and are collectively grouped as harmful algal blooms (HABs). This paper reviewed the various impacts of HABs in inland and coastal water bodies in Nigeria. Literatures of relevant and previous studies on HABs in inland and coastal water bodies in Nigeria within Nigeria and outside Nigeria were reviewed. The impacts of these HABs are felt in many ways: human health is placed at risk; ecosystems are altered; marine mammals are injured or killed; and the fishing, aquaculture, and recreation industries suffer substantial economic losses. Understanding the causes of these phenomena, and preventing their consequences, should be major concerns to Nigerians and the rest of the world at large. Moreover, although it is generally acknowledged that occurrences of these phenomena are increasing throughout the world's oceans, the reasons for this apparent increase remain debated and include not only eutrophication, and climate change but increased observation efforts in coastal zones of the world. Algae are a natural component of the aquatic food chain and are typically not harmful to people. However, the overabundance of algae in a bloom can be aesthetically unappealing and harmful to the environment. If the types of algae that produce toxins reach high concentrations, then native aquatic organisms, and perhaps even people who come in contact with the toxins, can be affected.The public should be educated via various scientific outlets and outreaches on extreme environmental events such as HABs and their health effects on humans and aquatic ecosystems.