![]() ![]() Not surprisingly, HABs are a major threat to today’s shellfish industry as well. Alaska first recorded issues with shellfish poisoning associated with algal blooms in the late 1700s. Harmful algal blooms have afflicted coastal communities for centuries. As a result, nearby fauna, including seabirds, fish, marine mammals, and sea turtles, can be poisoned or may alter their feeding behavior, which can sometimes prove fatal. And excessive algal growth can increase levels of toxic compounds and decrease water clarity. Microbial breakdown of large quantities of dead algae can cause hypoxia (low oxygen levels) or anoxia (depleted oxygen levels) in the surrounding water. HABs have several negative effects on aquatic ecosystems. Respiratory and digestive symptoms and illnesses, sometimes severe, caused by airborne and waterborne toxins emitted during some HAB episodes are the most common impacts on human health. Get the most fascinating science news stories of the week in your inbox every Friday. Part of Corpus Christi Bay where the author and his colleagues have collected water samples is seen here in August 2015, 1 month prior to the development of a harmful algal bloom. The common thread is that they are toxic to aquatic life as well as to people. Meanwhile, blooms of blue-green algae (which are actually cyanobacteria rather than algae) commonly occur in freshwater and saltwater settings. Red and brown tides, aptly named for the hues they contribute to coastal waters, are caused by certain algae species-such as Karenia brevis and Aureoumbra lagunensis along the gulf coastlines of Florida and Texas. HABs come in different varieties-and colors-and occur in both marine and freshwater settings. With their growing frequency, duration, size, and impact over the past 30–40 years, doing nothing to control them is not an option rather, it is becoming increasingly crucial that we establish HAB early-warning systems and response strategies to help safeguard communities today as well as future generations. In south Texas, where I live and conduct environmental research, HABs also are emerging more often along the Texas coast. HABs are also becoming more frequent and are occurring over larger areas, as in the coastal waters of the northern Beibu Gulf, China, where HABs have expanded from covering tens of square kilometers in the late 20th century to hundreds more recently. In South Korea, for example, HABs typically lasted less than a week in the 1980s, but since 1995, they have often lasted more than a month. Harmful algal blooms (HABs) appear to have escalated globally in recent decades. Yet some species produce compounds toxic to humans and wildlife, and at high enough concentrations, even species that are typically harmless can become harmful. Not all algae are hazardous-as a group, algae are, after all, nearly ubiquitous inhabitants of marine and freshwater environments. It is becoming increasingly crucial that we establish harmful algal bloom (HAB) early-warning systems and response strategies to help safeguard communities today as well as future generations. And in mid-July, residents were advised about possible blooms in Lake Micmac near Halifax, N. Shortly before those instances, similar warnings were issued for Red Bud Isle near Austin, Texas, and for Minnesota’s Lake Hiawatha and Lake Harriet. The same day, the Florida Department of Health in Orange County cautioned Orlando area residents not to drink from or swim, wade, or boat in waters with visible algal blooms in two of the city’s lakes. City officials had previously discontinued using water from the lake for drinking, and in response to MoDNR’s notice, they temporarily closed the lake to public recreation. More and more, however, they are having to cancel their plans, or at least stay out of the water, as reports come in from all over the United States and elsewhere warning of unwelcome summer visitors: algal blooms.Īmong numerous recent examples, the Missouri Department of Natural Resources (MoDNR) notified the city of Sedalia on 13 June of a potentially hazardous algal bloom in nearby Springfork Lake. With the annual emergence of summer heat, happy vacationers and weekenders are often eager to cool off at nearby lakes and beaches.
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