The Ohio Academy of Science annual meeting-April 12, 2008 the University of Toledo.

Lake Erie Symposium Morning Session

Nitschke Auditorium

09:00 AM

INTRODUCTION TO THE "DECLINING WATER QUALITY IN THE WESTERN LAKE ERIE BASIN" SYMPOSIUM. Julie P. Weatherington-Rice, weatherington-ri.1@osu.edu, Bennett & Williams Environmental Consultants Inc., Columbus,

Beginning in the mid-1990s, the National Center for Water Quality Research at Heidelberg College, Tiffin OH, noted an increase in the soluble reactive phosphorus portion of the total phosphorus in surface water collected at their sampling stations in northern Ohio. The levels of soluble phosphorus have continued to increase during the last decade (1997 through 2007), although levels of total phosphorus have remained constant or declined. During the fall of 2006, an invasive southern fresh-water blue-green algae (cyanobacteria), Lyngbya wollei, was first identified in Maumee Bay. Identification and habitat research was spearheaded by researchers at University of Toledo's Lake Erie Center. These two research organizations and the Western Lake Erie Association convinced the Ohio Environmental Protection Agency to convene the Lake Erie Phosphorus Task Force, which was charged with identifying the source(s) of the increased levels of soluble phosphorus (consumed by the blue-green algae), and making recommendations for curtailing loading levels. The Task Force has identified a number of sources of soluble phosphorus and is examining them methodically to determine which provide major contributions. Identified sources include agriculture, point sources, urban/ residential sources, internal loading in the lake, and other natural sources. This symposium will report on the research efforts of Task Force members and other scientists, including discussions of identified phosphorus reduction techniques that can be adopted by the citizens of the watersheds to slow down and/or reverse the eutrophication of the Lake, ostenstibly caused by degradation of algal mats at the bottom of the Lake.

09:15 AM

CHRONOLOGY OF HARMFUL ALGAL BLOOMS IN WESTERN LAKE ERIE: 2002-2007 Thomas B. Bridgeman, Thomas.Bridgeman@utoledo.edu, University of Toledo Lake Erie Center, 6200 Bayshore Rd Oregon OH 43618

Since the mid-1990s, harmful algal blooms hare plagued the waters of western Lake Erie with increased frequency. These blooms adversely affect water quality in terms of aesthetics, recreational use, and potentially, human health. In vessel-based observations made from 2002-2007, the most common nuisance species was Microcystis aeruginosa, a cyanobacteria that forms blooms during summer months. Microcystis blooms from 2002-07 were quantified using biweekly plankton tows (N=145) and a density separation method to separate Microcystis from other species. Patterns of bloom timing and density were then compared to USGS data from a major nearby tributary, the Maumee River, that is linked to bloom development by delivering the algal nutrients phosphorus and nitrogen to Lake Erie. Highest summer bloom volumes occurred in years with highest summer river flow (2003, 2004), while the lowest Microcystis volume occurred in the driest summer (2002). In addition to Microcystis, another cyanobacteria species, Lyngbya wollei, previously unreported in Lake Erie, formed large benthic mats along the southern shoreline of Maumee Bay in late summer of 2006. In September 2006, Lyngbya mats washed ashore, fouling beaches, private marinas, and shoreline property with layers of biomass up to 1.3 m thick. Early observations of Lyngbya mats suggest that the extent of shoreline fouling may depend on wind direction and water currents during the period in late summer when mats become mobile.

9:30 AM

DETECTION AND QUANTIFICATION OF MICROCYSTIS IN LAKE ERIE, OH. Hui Wang (jywanghui@hotmail.com), Cyndee Gruden, Cyndee.Gruden@UToledo,Edu

Dept of Civil Engineering, University of Toledo, 2801 W Bancroft St, Toledo OH 43606.

Microcystis blooms occur annually in the Western Lake Erie Basin. Microcystis produces a toxin which can be fatal to livestock and humans. Since Lake Erie is a drinking water source and a recreational site, it is necessary to minimize direct impacts to human health. The main objective of this research was to determine the factors affecting the spatial and temporal variation of Microcystis during and after a bloom in Western Lake Erie. In this study, surface water samples were collected from six sites (4P, GR1, 8M, MB18, MB20 and 7M) varying in distance from 2 to 30km from the mouth of the Maumee River. In situ measurements included dissolved oxygen concentration, pH, turbidity, and temperature. Samples were collected over a period of 3 months (6 events from July to October) in 2007. Each sample was settled in the graduated cylinder for 48 hours to separate Microcystis, and fluorescence microscopy was used to count Microcystis cells. Microcystis density ranged from 56 to 1.03x[10.sup.7] cells/ml. The massive Microcystis bloom occurred from mid-July to August when most sites sampled (11 of 18) had densities over 10,000 cells/mL. Site 8M located approximately 15km from the Maumee River had the highest concentration of Microcystis for 4 of the 6 sampling events. ANCOVA model was set up and analysis of environmental data as compared to Microcystis densities was performed by SAS program. The results suggest that temperature, nutrient concentration, turbidity, and DO concentration may have an impact on the Microcystis density.

9:45 AM

DECLINING WATER QUALITY IN WESTERN LAKE ERIE: CORRELATIONS BETWEEN SOLUBLE REACTIVE PHOSPHORUS (SRP) LOADING AND PHYTOPLANKTON BIOMASS. Douglas D. Kane, dkane@defiance.edu, Joseph D. Conroy, conroy.27@osu.edu, R. Peter Richards, prichard@heidelberg.edu, David B. Baker, dbaker@heidelberg.edu, David A. Culver, culver.3@osu.edu Defiance College, Natural Sciences and Mathematics Division, Defiance, OH, 43512.

Many hypotheses have been advanced to explain recurrent algal blooms in the western basin of Lake Erie, including abiotic (e.g., total phosphorus load) and biotic (e.g., dreissenid mussel excretion) explanations. We used two long-term (10 + year) datasets to test whether total phytoplankton biomass and cyanobacterial biomass correlated with soluble reactive phosphorus (SRP) loading from agriculturally-influenced tributaries (Maumee and Sandusky rivers) to the western basin of Lake Erie. We constructed linear regression models to determine if total phytoplankton biomass (and cyanobacterial biomass, individually) increased with recent SRP-load increases. Both total phytoplankton and cyanobacterial seasonal (May-October) average (arithmetic mean) wet-weight biomasses (mg [L.sup.-1]) significantly increased with increased water-year total SRP load (metric tons = Mg) for the Maumee River (both total phytoplankton and cyanobacteria biomass vs. SRP load: P = 0.008, [R.sup.2] = 0.56) and the sum of SRP load for the Maumee and Sandusky rivers (total phytoplankton biomass vs. SRP load; P = 0.007, [R.sup.2] = 0.57, cyanobacteria biomass vs. SRP load: P = 0.008, [R.sup.2] = 0.56), but not for the Sandusky River (P > 0.05). However, when using seasonal median total phytoplankton and cyanobacterial biomasses as response variables to remove the influence of bloom events and the Beale Ratio Estimator to account for missing SRP data, only the relationship between median cyanobacterial biomass and Beale-ratio estimated SRP load were significant (P < 0.05). In conclusion, recent increased western basin tributary SRP loads possibly contribute to increases in phytoplankton biomass and more frequent algal blooms, especially cyanobacteria, in the western basin of Lake Erie.

10:00 AM

COMPARING ANNUAL TRENDS OF DISSOLVED OXYGEN DEPLETION IN LAKE ERIE: THE IMPORTANCE OF WEATHER. Joseph D. Conroy, conroy.27@osu.edu, Aquatic Ecology Laboratory, Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH 43212.

Studies of the temporal dynamics (e.g., dissolved oxygen depletion rate) and the annual areal extent of zones of hypoxia (low oxygen, < 4 mg [O.sub.2] [L.sup.-1]) and anoxia (no oxygen, < 1 mg [L.sup.-1]) in Lake Erie often focus on the perceived influence of external nutrient load and, in turn, the perceived effects of people on affecting oxygen loss. However, bulk hydrodynamic processes as induced by weather may serve to diminish (e.g., through storm-caused mixing) or amplify (e.g., through water-column stagnation with low storm frequency) the effects of nutrient load on hypolimnetic oxygen loss. Here, I investigated how weather (wind speed) and associated hydrodynamic processes (wave height, water level) affected water column dissolved oxygen concentration (DO) in the Sandusky subbasin of Lake Erie during 2005 and 2006. I measured temperature and DO at 0.5-m intervals with a calibrated multiparameter instrument (YSI Model 6600) at a site in the middle of the Sandusky subbasin on 19 and 17 dates in 2005 and 2006, respectively. Weather and hydrodynamic process data for both years were downloaded from National Oceanic and Atmospheric Administration websites (wind speed and wave height station 45005: http://www.ndbc.noaa.gov; water level station 9063079: http://tidesandcurrents.noaa.gov) and daily means were calculated. Initial water column stratification occurred in late-May following periods of calm, low wave-height weather conditions. Hypolimnetic DO dropped below 1 mg [L.sup.-1] by late-June in both years. The hypoxic zone maintained its volume under stagnant conditions and expanded and contracted with increased wind speed, wave height, and water level oscillations indicating the importance of weather and hydrodynamic processes on DO dynamics in Lake Erie.

10:15 AN

THE IMPORTANCE OF LIGHT PENETRATION AND CHLOROPHYLL CONCENTRATION ON METALIMNETIC OXYGEN MAXIMA (MOM) DEVELOPMENT IN LAKE ERIE. Joseph D. Conroy (1), conroy.27@osu.edu, Gwen L. Dubelko (2), dubelko.2@osu.edu, Sophie B. Lehmann (3), slehmann08@wooster.edu, Douglas D. Kane (4), dkane@defiance.edu, and David A. Culver (1), (1) Dept of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, Ohio 43212, (2) School of Environment and Natural Resources, The Ohio State University, (3) Dept of Geology, College of Wooster, and (4) Natural Science and Mathematics Division, Defiance College.

Recurring seasonal hypoxia (low dissolved oxygen DO concentration, < 4 mg [O.sub.2] [L.sup.-1]) and anoxia (< 1 mg [L.sup.-1]) greatly affects pelagic and benthic biota in Lake Erie's central basin. Here, we report the presence of metalimnetic oxygen maxima (MOM) throughout the Sandusky subbasin, the southwest portion of the central basin during 2005, 2006, and 2007. Using weekly (or more frequent) vertical-profile sampling of water temperature (degrees Celsius) and DO at 0.5-m intervals at seven sites in the Sandusky subbasin during summer (June-August), we found that MOM frequently occurred (in 72 of 135 DO vertical profiles) during 2005-2007. We hypothesized that the shallow depth (mean depth = 13.3 m relative to the central basin mean depth = 18.5 m) and high productivity (as chlorophyll a concentration, Chl a) of the Sandusky subbasin permitted adequate light penetration (as Secchi Disk transparency, SD) facilitating metalimnetic phytoplankton growth. We tested this prediction in 2007 and found that deeper, eastern subbasin sites more frequently had DO profiles with MOM than shallower, western subbasin sites (about 67% of the profiles versus 33% for eastern and western sites, respectively). However, neither Chl a nor SD predicted MOM occurrence (P > 0.05, [R.sup.2] < 0.10). These results reveal that either light penetration or the presence of primary producers is unimportant for MOM occurrence or that our temporal and spatial scales of investigation did not appropriately identify effect scales. Nevertheless, occurrence of MOM in the Sandusky subbasin and possibly the rest of the central basin may ameliorate hypoxic and anoxic conditions.

10:30-11:00 AIR: Morning Panel Discussion

Lake Erie Symposium Afternoon Session

Nitschke Auditorium

1:30 PM

INCREASING TRENDS IN DISSOLVED PHOSPHORUS LOADING TO LAKE ERIE FROM NORTHWESTERN OHIO WATERSHEDS: 1994-2007. David B. Baker dbaker@heidelberg.edu, John P. Crumrine jcrmrin@heidelberg.edu, , R. Peter Richards prichard@heidelberg.edu, and Jack W. Kramer jkramer@heidelberg.edu. National Center for Water Quality Research, 310 E. Market St, Tiffin OH 44883.

To support nutrient management programs in the Lake Erie Basin, the National Center for Water Quality Research at Heidelberg College has been monitoring the export of nutrients and suspended sediments from northern Ohio watersheds since 1975. Using automatic samplers located at U.S. Geological Survey stream gages, three or four samples per day have been collected on a year-round basis, with multiple samples per day analyzed during storm events and single samples per day during non-storm periods. Between 1976 and 1985, total phosphorus loads to Lake Erie averaged 13,299 metric tons, with nonpoint sources accounting for 72% of the total. These observations led to the initiation of various conservation tillage programs to reduce erosion and export of suspended sediments and particulate phosphorus. Between 1976 and 1995, these conservation programs resulted in reductions in suspended solids and total phosphorus loading from the Maumee and Sandusky watersheds by 22% and 44%, respectively. Dissolved reactive phosphorus had dropped by an even larger 86%. Although suspended sediment and particulate phosphorus loading has continued to decline since 1995, dissolved reactive phosphorus loading has increased dramatically, now reaching or exceeding the late 1970 values. Because 100% of dissolved reactive phosphorus is bioavailable to algae, these loading trends warrant examination as potential causes of recently observed increases in blue-green algal growth in western Lake Erie. The dissolved phosphorus loading from the Maumee and Sandusky watersheds is primarily associated with storm runoff events, which indicates that agricultural runoff is the major cause of the increased soluble phosphorus export.

2:00 PM

PHOSPHORUS TRANSPORT FROM THE SOIL TO SURFACE WATER, FIELD OBSERVATIONS SUPPORTED BY A REVIEW OF CURRENT LITERATURE. Patrick D. (Rick) Wilson Rick.Wilson@epa.state.oh.us. Ohio EPA, Division of Surface Water, CAFO Unit, Columbus, Ohio, 43216.

As part of the investigative practices of the Division of Surface Water-Concentrated Animal Feeding Operation Unit at the Ohio EPA, surface and subsurface drainage and in-stream water quality samples are collected during runoff events from the agricultural landscape (including manure application sites). Water quality analyses of these events indicate that the soluble phosphorus component of the total phosphorus concentration may be more significant than is regularly reported, and demonstrates the need for more multivariate data collection at the sub-watershed scale. These analyses support the data collected by the National Center for Water Quality Research at Heidelberg College, and also highlight the need to associate water quality data with watershed nutrient management and soils data. Because of significant increase of both soluble reactive phosphorus loads in watersheds draining into Lake Erie and blue-green algae populations in the western basin, the Ohio EPA established the Lake Erie Phosphorus Task Force. The Task Force has conducted an extensive literature review to further understanding of the relationship of phosphorus build-up in soils, nutrient management in the agricultural landscape and the translocation of soluble reactive phosphorus to surface water. Although cursory, field investigations and sampling of runoff in agricultural regions of the state (where nutrients are applied in the form of manure, and inorganic fertilizer) seem to correlate well with research conclusions from literature that suggest nutrients will be lost where nutrients are applied to land such that it is prone to runoff. Consequently, improved nutrient management techniques for fertilizers (timing, rate, form) will reduce the load of runoff from land.

2:15 PM

ELEVATED SOIL TEST PHOSPHORUS LEVELS MAY EXPLAIN INCREASING DISSOLVED REACTIVE PHOSPHORUS CONCENTRATIONS AND LOADS IN WESTERN LAKE ERIE TRIBUTARIES. John P. Crumrine jcrumrine@heidelberg.edu, David B. Baker dbaker@heidelberg.edu, R. Peter Richards prichard@heidelberg.edu. National Center for Water Quality Research, 310 E. Market St, Tiffin, OH 44883.

Over the past 12 years concentrations and loads of dissolved reactive phosphorus (DRP) have been increasing in western Lake Erie tributaries and may be leading to increased blue green algae growth and degraded water quality for swimming, fishing, and drinking. In the predominantly agricultural watersheds of the Maumee and Sandusky rivers, northwest Ohio DRP increases came from one or more of three sources: commercial fertilizers, animal manures, and soil fertility measured by soil test phosphorus (STP). An evaluation of STP data from commercial laboratories indicates that STP levels average twice those needed for optimal corn and soybean production. Data further show that reduced and no-tillage crop production systems can elevate STP levels at the 0-2 inch (0-5 cm) depth by as much as two times over levels from a standard 0-8 inch (0-20 cm) soil test. In counties having large livestock or poultry numbers, where past manure application has produced high standard STP levels, reduced tillage and no-till can cause very high STP levels at the 0-2 inch (0-5 cm) depth. In a study to evaluate phosphorus stratification in cropland soils of the Rock Creek watershed, Seneca County, Ohio, STP levels at the 0-2 inch (0-5 cm) depth were doubled under no-tillage and increased one and a half times under reduced tillage systems compared to a standard 0-8 inch (0-20 cm) soil test. As contrasted to commercial laboratory data, standard STP levels were not highly elevated, partly because of low livestock numbers within the watershed.