Ohio Sea Grant Fact Sheets Harmful Algal Blooms in Ohio Waters Eugene C. Braig IV Ohio Sea Grant College Program 614.247.6684 What is [email protected] Joseph Conroy Ohio Department of Natural Resources Division of Wildlife 740.928.7034, Ext. 226 this stuff? [email protected] Frank Lichtkoppler Ohio Sea Grant Extension 440.350.2582 [email protected] William E. Lynch Jr. OSU Extension School of Environment and Natural Resources Center Erie Lake Toledo, of University Bridgeman, Tom Dr. 614.292.2265 [email protected] Linda Merchant-Masonbrink Ohio EPA Division of Surface Water 614.644.2001 linda.merchant-masonbrink@ epa.state.oh.us Lyngbya bloom on Maumee Bay near Toledo. Harmful algal blooms (HABs) are so named because to grow in colonies. Blooms can look like slicks of many produce poisons (or toxins) that can cause illness opaque, bright green paint, but closer inspection often ATMOSPH ND ER A IC IC A N D A M or irritation—sometimes even death—in pets, livestock, reveals the grainy appearance of individual colonies. E I C N O I S L T A R N A and humans. An algal bloom is an abundant or excessive While most HABs in Ohio will appear greenish or T O I I O T N A N U growth of algae. Most HABs are caused by planktonic sometimes black, cyanobacterial blooms can have a wide E .S . C D R E E P M A M bacteria, which are suspended in the water and rely variety of appearances; some may appear blue-green, RT O MENT OF C on currents to move them. The term “algal” is a little purple, red, white, or brown. misleading because the organisms that normally make up Not all algal blooms or surface scums are HABs. Be HABs are actually cyanobacteria, which are commonly careful not to confuse cyanobacterial referred to as “blue-green algae,” and are not true algae. surface scums with the small and Like plants and true algae, cyanobacteria have a harmless aquatic plants called pigment called chlorophyll that captures sunlight duckweeds. Some true algae to photosynthesize sugars for energy. Aquatic like Cladophora can also plants and algae require nutrients, especially create large blooms with phosphorus and nitrogen, from the water or the right nutrient and light sediment to grow. Unlike most plants and true conditions. Such blooms can algae, many cyanobacteria are able to pull and be a serious nuisance and use (or fix) nitrogen from the atmosphere using Microcystis cause environmental problems specialized cells called heterocytes. but do not generate the toxins Cyanobacteria can be distributed throughout the associated with many cyanobacteria. water or they can float to form scums on or near the Nuisance blooms of green algae are not OHSU –FS-091–©2010 surface. The cells of many cyanobacteria group together addressed in this fact sheet. This project was funded in part through the Lake Erie Protection Fund. The LEPF is supported by the voluntary Many HAB-forming organisms are native to Ohio but only cause problems when contributions of Ohioans who environmental conditions—often human-induced conditions—favor them. Lake purchase the Erie… Our Great Lake license plate featuring Erie’s most prevalent HAB-forming organisms include Anabaena, Aphanizomenon, the Marblehead Lighthouse: lakeerie.ohio.gov and Microcystis (this trio is sometimes known as “Annie, Fannie, and Mike”). There are several common, often visible cyanobacteria that make up HABs in Ohio: Microcystis Lyngbya • Globular colonies that can adjust their buoyancy to move • Colonies of clustered filaments, usually visible to the naked up and down through the water column eye that often form dense mats along the bottom that float • Cannot fix nitrogen from the atmosphere to the surface later in the growing season • Most dominant cyanobacteria in Ohio’s Lake Erie waters • Lacks specialized cells but still fixes nitrogen from the atmosphere Anabaena • One of Ohio’s recently problematic species (specifically • Colonies of hair-like filaments that can be planktonic or Lyngbya wollei, also known as Plectonema wollei), especially form mats along the bottom or near shore on Maumee Bay near Toledo • Can fix nitrogen from the atmosphere using specialized cells Nostoc Aphanizomenon • Colonies of filaments that usually clump into a green, • Colonies of planktonic filaments that often bundle together gelatinous, “marble-like” ball • Can fix nitrogen from the atmosphere using specialized cells • Can fix nitrogen from the atmosphere using specialized cells • Sometimes sold as a dietary supplement. Consuming could • Sold as a dietary supplement. Consuming could be be dangerous because this supplement is not regulated and dangerous because this supplement is not regulated and may contain cyanobacterial toxins. Consumers beware! may contain cyanobacterial toxins. Consumers beware! Cylindrospermopsis Planktothrix (also known as Oscillatoria) • Colonies of planktonic filaments that distribute through • Colonies of planktonic filaments that distribute through the water the water • Can fix nitrogen from the atmosphere using specialized, • Lacks specialized cells but still fixes nitrogen from the teardrop-shaped cells atmosphere • A recent invader to Ohio’s Lake Erie waters and • Dominates recent HABs on Grand Lake St. Marys and is Buckeye Lake very common to Ohio’s inland lakes and reservoirs What causes HABs to form? Extensive HABs have been observed in Lake agriculture, lawn fertilizers, wastewater Erie, the Ohio River, and many inland Ohio treatment plants, sewer overflows, leaking septic water bodies. They can occur almost anywhere systems, and precipitation. Forests and wetlands there is water: lakes, ponds, stormwater are natural filtering and buffering zones. As retention basins, rivers, streams, or reservoirs. wetlands have been depleted, pollutants and Knowing what triggers HABs is key to excessive nutrients have more easily entered our reducing their occurrence and impacts. HABs waters, where they potentially fuel algal blooms. may be minimized, and some completely Low oxygen and some biological activities can EPA Ohio Crawford, Jim avoided, by reducing the nutrients and also recycle nutrients stored by the system and pollutants added to the water. thus fuel blooms. Factors that can contribute to HABs include: Because many HAB-forming species can • excess nutrients (phosphorus or nitrogen), use nitrogen from the atmosphere, they are • sunlight, often very successful in systems with low • low-water or low-flow conditions, nitrogen concentrations where plants and true • calm water (low-wind conditions), algae might not do so well. When a resource (because • warmer temperatures, or nutrient is scarce enough that growth is of sediment • low salinity, and directly linked to its abundance, that nutrient is input from the • selective grazing (avoiding cyanobacteria) considered limiting. Lake Erie algal growth, for river and resuspended lake sediment) protects by zooplankton or zebra/quagga mussels. example, is phosphorus—rather than nitrogen— Microcystis from too much sunlight (which can Many of these factors can occur limited. In Maumee Bay, Microcystis growth over kill it). Low light minimizes competition from simultaneously in Lake Erie and Ohio’s inland the summer is closely related to the summer other algal species by shading them out (see Dr. waters. Nutrients that contribute to HABs and flow of the Maumee River, which presumably Tom Bridgeman’s work in Twine Line Vol. 31, other algal blooms (mostly phosphorus and is because it brings more phosphorus into the No. 3 at ohioseagrant.osu.edu/_documents/ nitrogen) come from many sources, including lake to fertilize blooms. Low light availability twineline/v31i3.pdf). Linda Merchant-Masonbrink, Ohio EPA Ohio Merchant-Masonbrink, Linda So,what’s the problem? Planktothrix bloom distributed through the water of Grand Lake St. Marys. Harmful algal blooms can cause taste and odor problems in drinking The World Health Organization (WHO) has developed provisional waters, pollute beaches with scums, reduce oxygen levels for fish and guidelines for HABs that may impact human health (Table 1). Microcystin, other animals, cause processing problems for public water supplies, a hepatotoxin produced by Microcystis and some other cyanobacteria, is and may generate toxic chemicals. Cyanobacteria can cause a range of the only HAB toxin for which sufficient information exists to formulate problems for recreation and the environment, but at their worst they can a guideline. Increased monitoring of public drinking water should occur cause health problems because of their ability to produce toxins. whenever microcystin levels reach 1 part per billion (ppb). Potential risk to More than 40 freshwater species of HAB-forming cyanobacteria are human health from recreational contact is considered low at microcystin known to make toxins. The three main classes of toxins produced by concentrations up to 4 ppb and moderate at 20 ppb. cyanobacteria are: 1) nerve toxins (or neurotoxins); 2) liver toxins (or hepatotoxins); and 3) skin toxins (or dermatotoxins), which may cause Table 1. World Health Organization (2003) provisional guidelines for threats to human health from recreational contact with cyanobacteria. itching, rashes, or other allergic reactions. Cell concentration Chlorophyll a The presence of cyanobacteria does not necessarily mean that Human-health risk (per milliliter) concentration toxins are being produced. The level of toxicity depends on the strains Low < 20,000 cells 1-10 ppb present and environmental factors (i.e., the amount of nutrients, light, Moderate 20,000-100,000 cells 10-50 ppb temperature, stress, etc.). HAB toxicity also depends on the sensitivity, High > 100,000 cells Visible scums the age, and the sex of the animal or person that consumes or comes into contact with the toxin. Mats of Lyngbya blooming on Maumee Bay. Melinda Huntley, Ohio Sea Grant Sea Ohio Huntley, Melinda Dr. Tom Bridgeman, University of Toledo, Lake Erie Center Erie Lake Toledo, of University Bridgeman, Tom Dr. Microcystis blooms on Lake Erie near South Bass Island (above) and the Ohio River near Cincinnati (opposite).