Vol. 23,No.1 Water Spring 2011 Column Clean LakesProgram •OfficeofWaterQuality • IndianaDepartmentofEnvironmental Management chemical energyformedby photosynthesistopowertheirbodies: millions ofyearsago. produced byalgaeinthe“primordialsoup”thatexisted onearlyEarth know itwouldnothavebeenpossiblewereforalltheexcessoxygen that livingorganismscanuseforlife.ItissaidlifeonEarthaswe photosynthesis asthefollowingprocessshows: Oxygen isalsoproducedbyalgaeandaquaticplantsasaby-productof slow process,itisresponsibleformostofthedissolvedoxygeninourlakes. mixing bywaves.Althoughdiffusionfromtheatmosphereisarelatively 30 20 10 0 Table 1.Oxygensaturationinfreshwater. warmer water(Table 1). and salinity. Forexample,coldwatercancontainmoreoxygenthan greatlyandisinfluencedbytemperature,atmosphericpressure, can vary andDynamics Oxygen Properties different biologicalandchemicalprocessesinlakesstreams. water quality. Itisessentialforgilledfishandinsects,influencesmany oxygen (DO),themeasureofgaseousinwater, forgood isnecessary would itbe?”Forme,theanswerbedissolvedoxygen.Dissolved ~ BillJones Water QualityParameter? Oxygen –TheMostImportant Temperature ( • • • Carbon dioxide+Water +NutrientsLightGlucoseOxygen In respiration,thereverse processoccurswhereorganismsusethe Oxygen inlakesisconsumedby: Photosynthesis convertsthelightenergyofsuntochemical Oxygen (O The concentrationofdissolvedoxygeninunpollutedfreshwater I’m oftenasked,“Ifyoucouldsampleonlyonethingonalake,what Chemical reactions,forexample,thereductionof nitrate (NO water andonthelakebottom. dead organicmaterials(leaves,twigs,algae,fish,etc.) bothinthe Respiration ofaerobicbacteriaandmicrobesasthey decompose oxygen whenwebreathe) Respiration offishandaquaticorganisms(muchlike weconsume ammonia (NH Glucose +Oxygen Carbondioxide+Water +ENERGY 2 ) enterslakesfromtheatmospherethroughdiffusionand 0 4 C) Temperature ( ) inthehypolimnion. 86 68 50 32 0 F) Solubility(mg/L) 11.29 14.62 7.56 9.09 3 ) to When the concentration of DO in water is in equilibrium with oxygen in the atmosphere, it is called 100 percent saturated and occurs at the concentrations shown in Table 1. DO in biologically productive (eutrophic) lakes can become supersaturated when oxygen is produced by algae or rooted aquatic plants more quickly than it can escape into the atmosphere. In some cases, the DO concentration can build up to greater than 200 percent saturation (Figure 1). When DO concentrations exceed 110 percent saturation, harm may come to certain fish. Excess dissolved oxygen can lead, in rare cases, to Figure 1. Depth profiles of dissolved oxygen (DO) and oxygen saturation in Williams Lake, “gas bubble disease” in fish where Noble Co., Indiana from 8/2/2004. Excessive algal photosynthesis created supersaturated the oxygen bubbles or emboli can oxygen conditions in the surface waters (20 mg/L; 240 percent saturation) while respiration block the flow of blood through of bacteria decomposing dead organic matter consumed all the dissolved oxygen in the blood vessels. hypolimnion (0 mg/L; 0 percent saturation). The dashed vertical line represents 100 percent On the other hand, in saturation. biologically productive, thermally stratified lakes with an abundance of decaying organic material, the oxygen consumption by aerobic bacteria can use up much of the available oxygen in the hypolimnion, leading to under- saturated conditions. If bacterial respiration is great enough, anoxic conditions may result. Limnologists consider DO concentrations of less than 1.0 mg/L to be anoxic. The limnologist, Arthur Hasler, referred to strongly eutrophic lakes as being physiologically senile. Such lakes produce more plant and animal material than they can use or decompose. As a result, the excess biological material accumulates on the lake bottom as muck and may even reduce lake Figure 2. Where light is sufficient for photosynthesis to occur, oxygen is produced by depth. photosynthetic algae and plants. Mixing of atmospheric oxygen into lakes occurs within the It is quite common within epilimnion of thermally stratified lakes but the metalimnion prevents mixing throughout dense aquatic plant beds that the lake. The hypolimnion is often too dark for photosynthesis. The lack of oxygen input daytime dissolved oxygen is and the consumption of oxygen during bacterial respiration often lead to an oxygen supersaturated but night time DO deficit in the hypolimnion. A steady rain of dead plants, algae and other detritus provide is under saturated due to aquatic continual organic matter inputs to the lake sediments. plant respiration. Such large daily swings in DO can be devastating for aquatic animal life in dense aquatic saturated due to the mixing of affecting the saturation of oxygen plant beds. atmospheric oxygen into the in water (Figure 3). Figure 2 summarizes many flowing, turbulent waters. DO of the processes that affect the concentrations in rivers and Biotic Needs distribution of oxygen within lakes. streams may vary significantly over Sufficient dissolved oxygen in Dissolved oxygen in rivers time; however, this is largely due the water makes life possible for and streams is often 100 percent to changing water temperature fish, aquatic insects, gilled snails, 2 reduction reactions affect the forms of many aquatic chemicals in addition to phosphorus. For example, nitrate and ammonia are both inorganic, dissolved forms of nitrogen. Nitrate occurs readily in oxidizing conditions when oxygen is plentiful but ammonia occurs primarily in reducing conditions in the absence of oxygen, often within the hypolimnion. Ammonia is oxidized (converted) to nitrate when sufficient oxygen is present. Because of this, we can predict the forms of some chemicals in lakes based on the oxygen Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr concentrations (Figure 4). We Date would expect more nitrate than ammonia in well-oxygenated Figure 3. Annual DO variation in a stream is clearly influenced by water temperature. As water and the reverse in poorly waters cool DO concentration increases; as they warm DO decreases. oxygenated or anoxic water as shown in Figure 4. mussels, crayfish, frog tadpoles, the lake sediments. This process is Measuring dissolved oxygen and many other aquatic organisms. called internal phosphorus loading Measuring dissolved oxygen Different organisms have different and can be a significantinternal within lakes is an important preferred DO concentrations but, source of phosphorus loading to component of water quality in general, the following guidelines lakes. Internal phosphorus loading monitoring and assessment studies. apply: can significantly delay the recovery A modern dissolved oxygen meter 0-2 mg/L: not enough oxygen to of eutrophic lakes even after with a submersible probe is a support life external, or watershed sources, of simple and reliable tool to measure phosphorus are controlled. DO (Figure 5).The probes are 2-4 mg/L: only a few kinds of fish These chemical changes calibrated in an internal chamber and insects can survive due to the presence or absence containing moist, saturated air to 4-7 mg/L: acceptable for warm of oxygen are called oxidation- the theoretical saturation value water fish reduction reactions. While we won’t based on ambient temperature and describe the details here, oxidation- atmospheric pressure. 7-11 mg/L: very good for most stream fish including cold water fish

Chemical Changes The presence of oxygen allows many important chemical reactions to occur in water. For example, in well-oxygenated lakes dissolved phosphorus (phosphate) and iron combine to form an iron-phosphate precipitate that settles to the lake bottom. This is a very important chemical process that removes phosphorus from the water column, but it only occurs when oxygen is present. However, if lake water becomes anoxic, often seen in the hypolimnion, the iron-phosphate Figure 4. High oxygen concentrations within the epilimnion (0-1.5 m) and low bond breaks and phosphorus is concentrations within the hypolimnion (4-6 m) affect the quantity and form of nitrate, released back into the water from ammonia, and soluble phosphorus (SRP) within Hogback Lake on 6/29/2010. 3 excess organic matter in the activities and how your lake sediments and Crooked Lake has changes over time. For example, some, but not enough to render if the amount or depth of anoxia the entire hypolimnion anoxic, increases from year to year, the like Williams Lake (Figure 1) or lake is on a course for serious Hogback Lake (Figure 4). The large problems, even if the surface waters lake volumes of these lakes dilute don’t exhibit any symptoms of watershed inputs. Low internal eutrophication. biological productivity in Clear and Crooked lakes prevents the Summary excessive bacterial respiration that In this article, we’ve consumes DO because there is less learned why dissolved oxygen organic matter waste present for measurements are among the most bacteria to decompose. useful and important to make in The Crooked Lake DO depth lakes. This simple measurement Figure 5. Portable dissolved oxygen and profile also shows a phenomenon truly grants us a window into temperature meter with submersible somewhat common in some many biological and chemical probe as used in the Indiana Clean Lakes clear lakes – a metalimnetic oxygen processes that should be of interest Program. maximum at 6 meters. This to lake residents and users alike. In supersaturated oxygen layer summary, with dissolved oxygen is evidence of a dense layer of data, we can discover: photosynthetic algae at that depth With a modern temperature • If there is adequate oxygen for in the cooler, denser metalimnion. fish and other aquatic life. and dissolved oxygen meter, The cooler water slows the algal one can measure both the sinking rate because cool water is • How oxygen concentrations vary concentration of DO in the denser than warm water and some with depth or in different areas water (as mg/L) and the percent algal species actually prefer cooler of the lake or during the day. saturation of oxygen. As discussed water with less intense light. They • If we would expect internal earlier, percent saturation allows us happily photosynthesize under phosphorus loading in the lake. to evaluate the relative magnitude these conditions and the oxygen • Where photosynthesis and and importance of photosynthesis they create gives them away. respiration dominate within the and respiration within the lake. Taking DO measurements at lake and whether this could have A depth profile of oxygen different times helps explain how impacts on biota or chemistry concentrations and saturation your lake changes through the within a lake is made by seasons and through the years. You • Whether lake conditions are lowering the submersible probe could track how oxygen increases improving or degrading over down through the water and or decreases due to biological time. recording data at different depths. Limnologists typically measure DO and saturation at every meter of depth from the surface to just above the lake bottom. A depth profile thus made can reveal a variety of conditions of importance in assessing lake condition. Figure 6 illustrates DO depth profiles of two deep, high-quality Indiana lakes, Clear Lake in Steuben County and Crooked Lake in Whitley County. Both lakes are mesotrophic (medium level of biological productivity) and contain ample DO well down into the hypolimnion. The DO concentration in Clear Lake never goes below 5 mg/L and Crooked Lake doesn’t go anoxic until right Figure 6. DO depth profiles for two deep Indiana lakes – Crooked Lake in Whitley Co. near the bottom. These results (2008) and Clear Lake in Steuben Co. (2010). Despite their deep depth and strong thermal suggest that Clear Lake has little stratification, both lakes remain oxygenated in the summer hypolimnion. 4 The 23rd Annual Indiana Lakes Management Conference

The Indiana Lakes Management Conference occurred on March 24-26, 2011 at the Potawatomi Inn in Pokagon State Park. More than 150 lake residents and enthusiasts joined the Indiana Lakes Management Society for the 23rd annual conference. Many thanks to our sponsors including Aquatic Control, Aquatic Weed Control, Clarke Aquatic Services, Aquatic Enhancement and Survey, Indiana Watershed Leadership Academy, Figure 7. An enthusiastic group attending the 23rd Annual Indiana Lake Management Cygnet Enterprises, and Davey Conference filled the Lake James meeting room at the Potowatomi Inn. Resource Group. This year’s conference highlighted opportunities to make Skinner Lake were elected president the best management practices waves within your community. and vice-president of the society, that can address those issues. More ILMS welcomed Eric Eckl of Water respectively. ILMS would like to importantly, they’ve learned about Words That Work who hosted thank out-going board members watershed collaboration seeking a full-day session focused on Jed Pearson of Indiana DNR, Nate assistance from local and regional communication. Concurrently, Long of Aquatic Control, and Ed governmental agencies and non- individuals from around the state Spanopoulos of Cygnet Enterprises profit organizations. CLTLC’s highlighted on-going efforts to for all of their efforts during their partnership with the Steuben manage Indiana’s lakes. Sessions time on the board. County Drainage Board resulted focused on fisheries management, At their annual banquet, in improved stream stabilization state rules and laws affecting ILMS recognized the ILMS to a tile outlet and through their Indiana’s lakes, partnerships Student Scholarship recipients, efforts to restore a wetland within between lake associations and Lake/Watershed Group of the their watershed; they’ve enlisted professional managers, and the Year, the Volunteer of the Year, the assistance of the US Fish and latest happenings of the Lakes and the Legislative Award Wildlife Service. Their efforts Management Work Group (Figure winner. Scholarship recipients have expanded outside of their 7). Two Saturday workshops included Abigail Grieve, Indiana immediate landowners to include detailed management of lakes University School of Public and watershed landowners in their for plants and algae concerns Environmental Affairs; Caitlin efforts as well. While CLTLC is and stressed the importance Grady of Purdue University; just getting started, their efforts and opportunities for partner and Matt Linn of Manchester serve as an inspiration to other development. College. Students received a $500 lake associations and watershed As part of the conference, ILMS scholarship and free conference groups showing just what can be completed their annual meeting. As attendance. accomplished from a small but part of this effort, ILMS members ILMS was pleased to recognize dedicated group of volunteers. elected new board members the Clear Lake Township Land ILMS also recognized Joe Kyle Turner of Beaver Dam/Loon Conservancy (CLTLC) for its Costello of the Sylvan Lake Lake Conservation Club, Brigitte commitment to improving Improvement Association for his Schoner of Whippoorwill Lake, conditions in and around Clear volunteer efforts and service to and Steve Lee of Aquatic Control Lake. Over the last few years, Sylvan Lake. For 33 of the past 40 and re-elected Heather Buck of CLTLC members educated years, Joe has unswervingly served Christopher B. Burke Engineering, themselves and watershed the lake. Accomplishments during Ltd. Additionally, Sara Peel of residents about water quality his tenure include: installation of a the Wabash River Enhancement influences on Clear Lake, Clear lake-wide sewer in 1974 (the second Corporation and Ed Sprague of Lake’s water quality issues, and of its kind nationwide); conversion 5 WATER COLUMN NONPROFIT ORG. U.S. POSTAGE School of Public and Environmental Affairs PAID Room 347 Bloomington, IN 1315 E. Tenth Street Permit No. 2 Indiana University Bloomington, IN 47405-1701

Clean Lakes Program

See a color version of this Water Column newsletter at: http://www.indiana.edu/~clp/ under “Publications.”

of the lake from a carp-dominated funded by the Town of Cedar breakfast for volunteers fishery to one of the best fisheries Lake and implemented by their participating in the Volunteer Lake in the state through a whole-lake employees, serving as a learning Monitoring Program on Saturday fish eradication and restocking in experience with techniques that morning. The breakfast offered the 1984; salvation of Boy Scout Island will be reproduced at additional opportunity for volunteers to meet through the $1.25 million purchase sites around the lake. For their with each other and with CLP staff of the island and future transfer innovation and perseverance, ILMS to talk about the program. Later of said island to the Gene Stratton was pleased to recognize the Town Saturday morning, three citizens Porter State Memorial. Joe’s efforts of Cedar Lake. were trained to become expanded to work to improve Sylvan Lake The Indiana Clean Lakes volunteer monitors (Figure 8). through his leadership and fund- Program convened a special raising were key in bringing this lake to its current high quality. Additionally, ILMS was pleased to recognize our first outstanding implementation project recognizing the Town of Cedar Lake. Since the late 1980s, the Cedar Lake Enhancement Association has been working to protect and enhance Cedar Lake and its watershed. The latest effort by the Cedar Lake Public Works Department to reduce stormwater impacts to Cedar Lake represents opportunities to innovate with low-cost solutions to standard problems. Clearing an existing right-of-way of overgrown trees and invasive honeysuckle and removing eroded material throughout the project area paved the way for the installation Figure 8. Abby Grieve (left) and Sarah Powers (center) train (l-r) Brigitte Schoner of rock check dams and native (Whippoorwill Lake), John Williamson (West Otter Lake), and Mike Marturello (Snow plants. This effort was completely Lake) along the shores of Lake James. 4