Blue-Green Algae Dynamics and Algal Toxicity:
A Study of Central Indiana Reservoirs

Following the documentation of toxic blue-green algae and an algal toxin in Geist Reservoir last year, CIWRP research into blue-green algae has been expanded into a comprehensive research program for 2008. Last summer, blue-green algae concentrations in both Eagle Creek and Geist Reservoirs, and the detection of microcystin toxin in Geist Reservoir resulted in recreational usage advisories being posted by the Indiana State Department of Health for both reservoirs. While the 2007 summer drought conditions created unusual conditions very favorable for the proliferation of blue-green algae, potentially toxic blue-green algae blooms have been occurring in central Indiana reservoirs for several years.  In fact, there have been documented cases of blooms of potentially toxic blue-green algae in several areas of Indiana since 2001.  Further, a review of blue-green algae research throughout the Midwest indicates that blue-green algae blooms and the occurrence of algal toxins, especially microcystin, are becoming increasingly common in midcontinent lakes and reservoirs.

For years, CIWRP research has focused on understanding phytoplankton (typically microscopic floating plants) occurrence and dynamics in area reservoirs because several types cause taste and odor in finished drinking water.  These compounds are likely familiar to you as the earthy and/or musty smell and taste sometimes present in drinking water. Nuisance algal blooms of taste and odor producing phytoplankton have been documented in Eagle Creek, Geist and Morse Reservoirs since at least 2000. Resident reservoir phytoplankton from diatoms to blue-green algae and actinomycetes (fungi-like bacteria) are known to produce taste and odor causing compounds - chemically known to be MIB (2-methylisoborneol) and geosmin. Further, certain species of blue-green algae are known to produce specific taste and odor compounds.  For example, Anabaena has been documented as producing geosmin and potentially MIB; Pseudanabaena has been shown to produce MIB; Aphanizomenon has been shown to produce geosmin; and Planktothrix has been shown to produce both MIB and geosmin. Yet understanding if these same species produce taste and odor compounds locally remains unknown and anecdotal.

In recent years, concern regarding the production and occurrence of blue-green algal toxins has grown in central Indiana and nationally. Evaluation of phytoplankton community structure information from Eagle Creek, Geist and Morse Reservoirs has shown that potentially toxic blue-green algae comprise important parts of the phytoplankton communities in mid-late summer and fall in all three reservoirs. Additional reports of potentiallytoxic blue-green algae in Indiana include Ball Lake in Steuben County, Lake Lemon and Monroe Reservoir in Monroe County, and at least 20 other lakes and reservoirs statewide.

Given the ecological, recreational, and municipal uses of Eagle Creek, Geist and Morse Reservoirs, maintaining and improving their water quality has been a focus of the Central Indiana Water Resource Partnership (CIWRP). A primary focus area has been on Eagle Creek Reservoir (ECR) because of the drinking water intake location within the reservoir. In 2003, CIWRP research focused on obtaining physical, chemical, and phytoplankton data to understand how ECR’s physical and chemical environments affect phytoplankton growth (Pascual and Tedesco, 2004a). Algaecide treatment was being used to control algal bloom formation more aggressively in 2003 with three algaecide treatments occurring in ECR in 2003. Thus a secondary focus of the 2003 study included determining algaecide treatment effectiveness (Pascual and Tedesco, 2004b).  Subsequent research designed to develop a rapid blue-green algae mapping tool utilizing remote sensing has resulted in monitoring the distribution of blue-green algae in the three reservoirs over the past three years (Li et al., 2006).  This work also included Monroe Reservoir in south-central Indiana, a drinking water supply reservoir for Bloomington and surrounding communities and an important recreational use resource. Our work provided snapshots of whole reservoir blue-green algae distributions with some information on the physical and chemical characteristics of the reservoirs and limited information on phytoplankton community structure. However, CIWRP research has not studied the occurrence of blue-green algal toxins in central Indiana reservoirs or elsewhere and information on the occurrence of algal toxins is very limited despite the fact that known toxin-producing algae comprise important components of blue-green algal populations in the three central Indiana reservoirs, as well as elsewhere throughout the state.

Given the importance of the central Indiana reservoirs for the drinking water supply and their recreational use, a comprehensive study of the phytoplankton ecology of the three reservoirs is being undertaken.  Additionally, documenting the occurrence of taste and odor compounds (MIB and geosmin) as well as blue-green algae toxin occurrence will be an important part of the study and will be undertaken during the spring, summer, and fall of 2008, and potentially 2009.

The 2008 CIWRP Algal Ecology and Toxicity study has three main purposes:

1)      To document algal community composition and abundance;

2)      To determine the relationship between physical and chemical reservoir conditions and algal community structure and abundance; and

3)      To document the occurrence of blue-green algal toxins (microcystin, anatoxin-a, and cylindrospermopsin) and taste and odor compounds (MIB and geosmin) and their relationship to algal community structure and reservoir conditions.

This study is already underway and will involve a lot of field work. We will sample Eagle Creek, Geist and Morse Reservoirs on every two weeks beginning in mid-May and extending through mid-October. This will result in at least 12 sampling events per reservoir. Additional samples may be taken in response to monitoring specific blooms or during unusual conditions.  Researchers will be monitoring physical and chemical reservoir conditions important to understanding the factors that lead to algal blooms and potentially even specific species of algae.  This type of monitoring will occur at a series of sites throughout each reservoir.  At a few select sites, we will collect water samples throughout the water column (for example at the surface, near the bottom, and at places in the middle of the water column where different important biological conditions occur).  These samples will be analyzed for a large number of parameters that can control algae community abundance and composition (eg. levels of the nutrients nitrogen and phosphorus, dissolved oxygen levels, amount of light etc). Additionally, samples will be analyzed for several measures that are created by the algal communities (eg. number and species  of phytoplankton present, levels of algal pigments present, amount and type of taste and odor compounds, and amount and type of algal toxins, if any, present).

CEES is partnering with both Veolia Water Indianapolis, LLC. though the CIWRP partnership, and with the State of Indiana (Indiana Department of Natural Resources, Indiana Department of Environmental Management and Indiana State Department of Health) to conduct these studies.  CIWRP funding will be the dominant funding source and will document reservoir physical and chemical conditions, algal community dynamics, taste and odor compounds, and some toxin analyses. The State of Indiana will provide limited funding for additional algal toxin analyses predominantly for Geist Reservoir with some additional analyses of Eagle Creek and Morse Reservoirs.  Specifically, CEES will collect samples for algal toxin analyses and results will be provided to the State for dissemination to the public via their website at www.algae.in.gov. CEES will not make recommendations to the public regarding health and safety associated with the use of recreational waters. The State will provide additional information to the public on their website.  CEES will continue to provide science-based information about blue-green algae and our understanding of the causes and conditions that help promote algal blooms as they become available.

This study is one of the first studies in Indiana that will document the occurrence of algal toxins on a biweekly basis throughout the growing season.  While there have been isolated tests for algal toxins on a few select lakes and reservoirs in response to a bloom or as part of a state-wide screening for one specific algal toxin, this study will provide important comprehensive information to help assess blue-green algal occurrence and reservoir conditions that might be responsible for blooms and toxin production.

CIWRP research and the expertise of CEES researchers (especially Tedesco, Clercin, Pascual, and new graduate student Angie Cowan) continues to provide important information and analyses. Our work has been important in that we have been able to provide information to state agencies, the Indiana legislature, Veolia Water, and the general public. We hope to be able to provide solid science data to the public policy arena as Indiana works to set standards, develop policies for advisories and determine if there is a need for statewide monitoring. We have posted some background information about blue-green algae on our website as well as presentations made at a public meeting for Geist residents. We will continue to provide updates and information as we learn more about our water resources and ways to improve, enhance and protect them.