Impacts of Harmful Algal Blooms (HABs) on Agriculture: A Short Communication

Abstract

agriculture, which requires clean water, healthy soil, and adequate nutrients, is crucial to meet the growing demand for food and fiber. Over application of nutrients to meet demand has degraded surface water quality, leading to accelerated eutrophication. Cultural eutrophication is a process by which aquatic ecosystems such as ponds, lakes, and estuaries become so enriched with nutrients—primarily nitrogen and phosphorus—as to become unusable for safe consumption and ecological purposes. Eutrophication has intensified due to climate change. Increased temperatures, intense storms, and drought can drive the formation of eutrophic and hypereutrophic conditions. Hypereutrophication results in the rapid proliferation of algae and phytoplankton, resulting in algal blooms. Harmful algal blooms (HABs), including the proliferation of cyanobacteria, which can produce cyanotoxins such as microcystins and cylindrospermopsin, can also grow in hypereutrophic conditions. These toxins can detrimentally impact humans, wildlife, and agricultural systems (e.g., fish, livestock, and crops). Fish that ingest algal toxins may suffer from liver damage and oxidative stress, with varying effects depending on the type of fish, the amount of exposure, and the duration of exposure to toxins. Additionally, a few studies report livestock death after drinking water contaminated with byproducts of HABs such as microcystin, nodularin, cylindrospermopsin, anatoxin-a, guanitoxin, and saxitoxin. The available research on the effects of microcystin on crops, vegetables, and fruits consistently demonstrates their negative impact. This short communication article summarizes the literature published between 2012 and 2022 documenting the impact of microcystins on agricultural commodities, particularly livestock and various crops. Although awareness has increased, few publications have discussed microcystin-related livestock deaths in recent years. However, numerous global studies have highlighted the harmful effects of microcystins on crops, fruits, and vegetables. The researchers suggest that in cases where the levels of microcystin exceed the standards established by the World Health Organization, careful monitoring is needed. Human exposure to microcystin may occur through the consumption of livestock, crops, and vegetables contaminated by microcystins through drinking or irrigation. More research is needed to understand the fate and transport mechanisms of microcystins in various agricultural settings, including controlled, simulated, and field experiments.