2010 Lakes Appreciation Month Student Poster Contest Winners

Each year NALMS recognizes the month of July as “Lakes Appreciation Month” and holds a student artwork contest to find an image or theme that will be used on a poster to advertise the event. This year more than 200 posters were submitted in response to a call for posters.

A working group of the NALMS Education Committee reviewed each poster and selected the top four to be voted on by the NALMS Board of Directors. Here the winner and the two runners-up from that vote are showcased.

The winning poster (pond with boats, top right) was submitted by Chyanne Kemp from Hawley, Pennsylvania. Chyanne is in the 7th grade. Chyanne’s artwork will be used as the background to the NALMS 2010 Lakes Appreciation Month poster, which will be used to publicize Lakes Appreciation month in July 2010.

The two runners-up in the contest were Jameson Doub (lake with cabin, middle right), and Sabah Kadir (goose on pond, lower right), both 7th graders from Kinston, North Carolina.

For more information about Lakes Appreciation Month, please visit the NALMS website at www.nalms.org, or contact Amy Smagula at [email protected].

4 Summer Summer 20102010 / / LAKELINE LAKELINE From the Editor Bill Jones

hen it comes to this issue’s Supersaturated Dissolved Oxygen John Beaver present a most interesting theme, I may have an injection. Solar-powered circulators discussion of microbial food webs. Wadvantage over most. No, (SPC) have been around for a while Microbial food webs aren’t new but we it’s not because I am so and their “green” status is certainly don’t talk or think about them very much. well-read. The truth appealing. Results have recently been Doug Pullman and Gary Crawford then of the matter is, my published in the peer-reviewed literature describe a new invasion of a macroalgae, desktop has a huge that describes how SPC successfully starry stonewort, in Michigan. pile of literature that suppressed harmful algal blooms in Planning is well underway for the I mean to get to, but several reservoirs. Kenneth Hudnell and next NALMS Symposium to be held in time – or the lack Joe Eilers review their research in our Oklahoma City (page 5). You can read all thereof – just doesn’t second article. about this conference and how to register allow it. One of my My former classmate in graduate for it in this issue of LakeLine. NALMS Dad’s favorite sayings, school, Joe Eilers, pulls double-duty is always looking for a few good men and he seemed to have a saying for in this issue and teams up with Holly and women to serve as directors and almost every occasion, was, “The road to Truemper to describe how Diamond officers. Check out the annual Call for Hell is paved with good intentions.” Well, Lake became the first to meet its TMDL Nominations (page 8). let me tell you, I’ve done a lot of paving! targets by reducing the internal loading Later, Amina Pollard of the U.S. No, I keep up-to-date with new ideas rate associated with fish poop. We’ve EPA summarizes the results of the 2007 and approaches because of my graduate regularly covered the latest developments National Lakes Assessment. We then students. They really keep me on my regarding HABs here in LakeLine, but hear about annual meetings held by three toes. If I can’t answer their probing the next article, by Steve Weber and of our NALMS Affiliates. We finished questions, I tell them so and do my best Jeff Janik, is the first I’ve seen about up this issue, as usual, with “Literature to come to class the next time with the toxic haptophytes. Karl Havens and Search.” Enjoy! answers. There is nothing like bright, young inquisitive minds to keep me sharp. So, when it came to identifying new approaches in the field of lake management to feature in this issue, I cast a broad net. We couldn’t possibly cover all new approaches developed in recent years in this single issue, but I think you’ll agree that we have some interesting ones. I understand that aeration is one of the oldest in-lake practices being used. We highlight two new applications of aeration in this issue. First off, Scott Osborn, Anna McCain, and Grace Richardson of BlueInGreen, LLC, describe their new method to add dissolved oxygen to water using

10 Summer 2010 / LAKELINE From the President Mark Hoyer

Why do we need new approaches? I have left in my office asking them if off this year the one I am most interested they know what it is and none of them do. in is increasing our student participation. am probably the wrong person to After that they generally show me 50 (+) The Board will be submitting to the write about new approaches because I plots with multivariate analyses that they membership in Oklahoma changes in the still wear some of the clothes I owned made using data sets with over 100,000 NALMS By-Laws that switches one of Iwhen I got married (30 years ago) observations made on a laptop in three the At-Large Director positions into a minutes. Then they ask me what I think. Student Director position. This will have and I support Henry Ford’s statement, “You I used to tell them to use a slide rule and to be approved by the full membership can have a Ford in any think about it some more but thinking in November at the annual membership color so long as it is now about the title of this article I need to meeting. If approved, this will give the black.” However, type tell them that we always need to consider students an active part in the governance “New Approaches” into new approaches. I hate to say it, but as of the society and hopefully bring a search engine, you technology improves, we need to embrace some much-needed energy to revitalize get 23,600,000 hits and it and use it to help us better understand NALMS pursuit of it’s mission. The it makes you wonder and meet our mission of managing lakes following is a summary of activity from what was wrong with and reservoirs. students that are already working under all of the old approaches. I have lived for The same holds true for non-profit the NALMS flag: many years repeatedly stating that if it is organizations like NALMS. Without not broken, don’t fix it. So why are there considering new approaches, the lifespan NALMS Student Summary: so many new approaches? of most non-profit organizations is One example of why we may want approximately 30 years. They start with The 2009 conference in Harford, CT to consider new approaches comes from a growth phase driven by a mission was very exciting for both the attending my experiences during graduate school. statement followed by a peak and then and current NALMS student members! I started to analyze data and write my slowly declining into a maintenance The NALMS Board members and thesis in 1980 and at that time I had a phase where the organization has no attending students had a luncheon where relatively large data set of 125 water new blood and all resources are used up we all got to know one another, share bodies, sampled three times a summer, to keep the organization alive but not stories, and, most importantly, discuss for two years (Hoyer and Jones 1982). pursue the original mission. NALMS ideas to improve student involvement Analyzing these data, I had to punch has peaked, was declining and spending (there were only 20 or so students in paper cards with character and numeric more time on inward maintenance than attendance at the conference). The codes that were read through a card reader outward missions. The good news is that students’ main concerns were (1) the and sent to a mainframe computer using I have just come from the NALMS 2010 lack of knowledge of NALMS and its SAS (Statistical Analyses System) to Mid-Term Board Meeting that was held in opportunities for present and future produce plots and statistical analyses. If Denver and I saw many signs of new life students and (2) funding to attend the the analyses and the plots were correct, and energy! conference. Thereafter, a few students then I had to use templates and India The Executive Committee, full Board took the initiative to create a student ink to trace the plots on tracing paper of Directors (minus one because of family cohort within NALMS to garner more for figures in my thesis and/or reviewed commitments), conference coordinator, student memberships and student publication. One plot took multiple days and staff attended the all-day meeting. involvement. There is now a NALMS to complete. Now many graduate students We have lots of new blood and energy student Web site (nalmsstudents.com), come to my office for help and I always on the board with excellent ideas. Of the which has had over 300 visitors and a show them one of the three punch cards several new initiatives that will be kicked Facebook page (North American Lake

Summer 2010 / LAKELINE 11 Management Society [NALMS] Students) Best Student Paper – Poster: ~ Dana Bigham, University of Florida, with over 30 members. More recently, we Nicole Reid (University of California- USA have begun to receive student inquiries Riverside) for her paper “Viliger ~ Kyle Borrowman, Trent University, about scholarships to attend the upcoming Abundance and Distribution in Four Canada NALMS conference in Oklahoma. We Reservoirs of the Colorado River have started to discuss ideas to increase Aqueduct.” Now that I have thrown a bone to available monies for NALMS student Best Student Paper – Presentation: those favoring new approaches, I want travel grants. We are also exploring some Dana Bigham (University of Florida) to be absolutely clear that some old ideas for special events for the students for her paper “Long-Term Trophic State approaches and/or Lake Managers are during the upcoming NALMS conference. Indicator Trends in Florida Lakes.” just like wine – always getting better with In addition to the Web site and time. At the next annual symposium find Facebook page, efforts have been made Honorable Mention Paper – Poster: some students, share your experiences to bridge the gap between students north Jordy Veit (Minnesota State University) with them and let them know what are and south of the 49th parallel. To increase for her paper “Determination of the the good old methods and the ones you Canadian student membership, letters Allelopathic Ability of Reed Canary Grass have thrown away. Let’s be active in have been sent to respective departments Grown With and Without Tussock Sedge in developing the next generation of Lake within Canadian universities to recruit Three Different Soils.” Managers. students to join NALMS and to submit Honorable Mention Paper – abstracts for the 30th Annual Symposium Presentation: in Oklahoma City this fall. Recruiting Andrew Oguma (Western Connecticut Mark Hoyer graduated from Iowa State Canadian students to join NALMS is just State University) for his paper “Potential University in 1979 and received his MS in one step toward creating a long-lasting for Stocked Watermilfoil Weevils to Limnology from the University of Missouri relationship for a new generation of lake Sustain Populations in Candlewood Lake: in 1982. From there Mark found his way to managers and researchers from across A Possible Biological Control of Invasive Florida and has researched the relationships the continent. This call for abstracts Eurasian Watermilfoil.” among water chemistry, aquatic macrophyte and student membership to NALMS will communities, fish and aquatic bird Sponsors: Hach International. hopefully lead to higher Canadian student communities in Florida streams, lakes and presence in Oklahoma City and the Student Awards Committee: Alex Horne estuaries for the last 28 years. Additionally, creation of regional Canadian chapters of and Frank Browne (co-chairs) and Mark helped start the Florida LAKEWATCH NALMS. Amy Smagula, Jody Connor, and Harry program in 1986, which currently works with We would like to take this opportunity Gibbons (members). over 1,500 citizen scientists who monitor to again express our congratulations the water chemistry of approximately 610 to the 2009 student paper winners and Finally, we urge the membership to lakes, 130 near shore coastal stations and thanks to the sponsors and Student support student participation in NALMS 125 river stations. Mark has been an active Awards Committee for making students a to the best of you ability because we are member of NALMS for 25 years. x special part of the NALMS family! the future!!!

“New Approaches” include having extra NALMS Board discussions at a baseball game in Denver and advertising to the crowd.

12 Summer 2010 / LAKELINE New Approaches

Introduction to SDOX®

Scott Osborn, Anna McCain, and Grace Richardson

New Method for Adding Dissolved Oxygen to Rivers and Shallow Lakes

upersaturated Dissolved ton of DO per day). The portability option During the low DO season at this location Oxygen (SDOX®) injection is allows for great flexibility when selecting (August through November), the DO a new method to add dissolved the best location for injecting DO into in the North Fork River can fall to near Soxygen (DO) to water. This environmental water. In addition, the 0 mg/L, resulting in fish kills and other patented/patents pending technology was SDOX is able to use river or lake water low DO impacts. As explained in more developed at the University of Arkansas as the carrier stream without any danger detail below, low DO in a tailrace can and has been exclusively licensed to the of clogging of either the SDOX or the also result in limitations on the amount Arkansas-based company, BlueInGreen, injection pipe as the minimal opening size and efficiency of hydroelectric power LLC. SDOX differs from many other is typically larger than a quarter (1/4”) generation. dissolved oxygen delivery techniques in of an inch. No filtering or pretreatment of Due to limitations of grant funding, that the oxygen is pre-dissolved inside the carrier stream is required, only coarse the pilot-scale SDOX unit was somewhat of a saturation tank and is delivered in a screening of the inlet pipe. undersized for the flow rate in the North side-stream of water. This system allows The SDOX has been tested in Fork River, but was still able to maintain for cost-efficient treatment of both rivers several settings related to river and lake the target dissolved oxygen concentration and lakes. Figure 1 describes the use of oxygenation including the tailrace river of 6 mg/L for 83 percent of the time SDOX in a river. of a hydroelectric dam; hypolimnetic during the study. It is important to note Using SDOX, the rate of DO oxygenation (without thermocline that the DO rise reported is from the added to a lake or river is minimally disruption) of both a shallow, warm SDOX alone; any additional DO increase affected by water temperature and DO recreational lake and a cold, deep that resulted from natural re-aeration or of the water being treated. Technologies, recreational lake; and shallow streams that from pulsing operations of the dam were such as bubble diffusers, that rely on feed a lake. subtracted from the final numbers. This dissolution of gaseous oxygen into bulk means that an SDOX unit of the proper water are affected significantly by the SDOX Oxygenation of Rivers size could have maintained the target DO temperature and DO of the water being and Streams of 6 mg/L 100 percent of the time and that treated. Because oxygen gas dissolves less Use of SDOX for dissolved oxygen pulsing operations of the dam would no efficiently as both temperature and DO addition in a river can help improve lake longer be necessary. The oxygen use rate of the water increases, bubble diffusers water quality in two ways: oxygenation of the SDOX was measured as 1200 lbs/ waste significant amounts of oxygen due of a tailrace river below a dam and day and three oxygen sensors were placed to off-gassing and become impractical oxygenation of a river flowing into a at 10 m, 100 m, and 1000 m downstream for warm water and shallow applications. lake. As part of a research project funded to measure the DO increase. Based on Conversely, SDOX predissolves the by the National Science Foundation, the an estimated flow rate of 156 cubic feet/ oxygen and is able to achieve very high ability of SDOX to add oxygen directly second, the overall rate of DO delivery to DO concentrations without wasting to a tailrace river was studied in the the tailrace river was 1150 lbs/day for an undissolved oxygen. Because of this high North Fork River below Norfork Dam overall oxygen delivery efficiency of 95 concentration, a relatively small amount in Baxter County, Arkansas (see Figure percent. The SDOX injected the dissolved of supersaturated water must be injected 2). This stretch of river has been placed oxygen at a depth of three (3) feet, and into the river or lake to bring the total DO on Arkansas’ 303(d) list due to seasonal the overall energy efficiency of this up to the target concentration. The result issues with low dissolved oxygen in deployment was 1.94 lb DO delivered per is a device with a very small footprint the waters released from Norfork Lake. hp-hr at this shallow depth. that can deliver a great deal of dissolved Because of a valuable trout population, The ability to efficiently oxygenate a oxygen (portable, trailer-mounted units the DO in this river must be at or above tailrace river is key to efficient generation are available that can deliver up to one 6 mg/L to meet water quality regulations. of hydropower. Many hydropower

Summer 2010 / LAKELINE 13 Figure 1. (A) Oxygen gas from a PSA unit or liquid oxygen tank vaporizer passes through a pressure regulator and into the gaseous oxygen headspace in the pressure tank. (B) Water is pumped from an upstream location in the river, through a spray nozzle, and into the top of the pressure tank. The spray nozzle atomizes the water into droplets. This mechanism allows the oxygen gas to dissolve into the water droplets nearly instantaneously. A second mechanism that increases the dissolved oxygen level is the pressure in the tank. This pressure greatly increases the amount of oxygen that can be dissolved into the water droplets (as compared to dissolution at atmospheric pressure). These two mechanisms cause the water to be supersaturated with oxygen and can achieve typical dissolved oxygen concentrations of 350 mg/L. The supersaturated water collects at the bottom of the tank. (C) The supersaturated water is released from the pressure tank and mixed rapidly with the water in the river at a downstream location. The energy used to pressurize the tank and increase the concentration of dissolved oxygen is recovered as energy used for mixing and distributing the oxygenated water. The specially designed orifice tube causes the supersaturated water to be broadly distributed very quickly such that the overall DO of the surrounding water is below saturation concentrations at atmospheric pressure. Mixing prevents the dissolved oxygen from exiting solution at the lower pressure outside the SDOX. The mixing rate can be controlled to achieve optimal target dissolved oxygen concentrations for a specific application. For example, mixing 1 liter supersaturated water (at 350 mg/L) with 86 liters river water at 2 mg/L will achieve an overall dissolved oxygen concentration of 6 mg/L. Using SDOX, the increase in dissolved oxygen is additive from any initial dissolved oxygen concentration and can target any final dissolved oxygen concentration up to saturation without off-gassing. SDOX is highly efficient and has documented operating cost savings up to 80 percent as compared to traditional dissolved oxygen delivery technologies. SDOX is most cost effective in shallow water applications between 3-50 feet of depth and at target dissolved oxygen concentrations from 3 mg/L to saturation. facilities across the nation employ pulsing, and other low DO dam • Easy access to SDOX equipment methods such as pulsing, turbine venting, operations located above the flood zone (only two and load spreading to add the minimal DO • Requires little to no modification to hoses will be in the river) needed to prevent fish kills during the low infrastructure or operation of the dam SDOX could also be used to add DO season in the summer and fall. These • Ability to maintain regulated DO level DO to a river that feeds a lake. Since low DO operations reduce the amount most low oxygen problems in lakes are and efficiency of hydropower generation. in the river at all times regardless of flow rate through the dam caused by deposition of excess organics Reductions in hydropower generation and nutrients from waters flowing into rates by up to 50 percent during the low • Minimized cost of operation by the bottom of the lake, oxygenation of the DO season have been reported at some oxygenating only the water exiting the inflow water that carries these organics locations (ADEQ 2009). dam could help deliver DO to depositional There are numerous benefits to • No possibility of implementation of in- locations where it is most needed. A long- SDOX oxygenation of a tailrace river (as lake fishing restriction due to fish being term strategy to increase the capability of compared to oxygenation of the forebay), attracted to oxygen bubble diffusers surface streams to process organics and including: nutrients before they enter the lake could • No clogging of oxygen diffusers due to • Reduction or elimination of need be an efficient approach to maintaining intermittent use or particulates in water for turbine venting, load spreading, lake water quality. The use of SDOX in

14 Summer 2010 / LAKELINE pull low DO water from and inject high DO water back into any desired layer of the lake, from the surface to the bottom of the lake. This setup will not change the temperature of the stratified layer being treated and will prevent disruption of the thermocline. In addition, vertical mixing due to bubble plumes will not occur. Dissolved oxygen delivery technologies that rely on dissolution of gaseous oxygen bubbles into the lake water can create upward currents that disrupt the thermocline. The mixing of the thermocline caused by bubble diffuser systems is more pronounced at higher DO concentrations; and it is often the case that these systems have a practical target DO maximum of 3 mg/L and are only applicable to deep water lakes (greater than 50 feet of depth). Furthermore, if the undissolved oxygen bubbles escape from the top of water column, the expensive oxygen gas is wasted to the atmosphere. The off-gassing of undissolved oxygen can add significantly to the operating costs of bubble diffusion systems. The National Science Foundation also funded tests to study the ability of SDOX to add dissolved beneath a thermocline. SDOX was used to document the formation of a DO plume at both Lake Atalanta in Rogers, Arkansas, which is a warm, shallow recreational lake, and Lake Brittany in Bella Vista, Arkansas, which is a deep, cold-water recreational lake. The SDOX was deployed in Lake Brittany as shown in Figure 3 at a depth of 30 ft. Temporary buoys were set up to allow for repeated measurements and characterization of the DO plume. In this experiment, buoy 9 was located 750 feet from DO injection at the orifice tube. Results prior to injection and after five days of continuous DO injection are shown. A dissolved oxygen concentration of 5-6 mg/L was readily achieved. The Figure 2. (Top) Photographs of pilot-scale SDOX deployed in the tailrace river below Norfork temperature profile of the lake indicated Dam. (Bottom) Fishermen just downstream of SDOX DO addition. the preservation of the thermocline throughout the experiment for both Lake this application has not yet been studied in at a specific location and/or depth in the Brittany and Lake Atalanta. detail. lake, the SDOX pressure tank, power The tests funded by the National supply, and gaseous oxygen source can Science Foundation are being put SDOX Oxygenation of Lakes be located on shore or on a floating into practice at Lake Thunderbird in and Reservoirs barge. This would allow for targeted Central Oklahoma. In 2010, the Central A third use of SDOX is for oxygenation of a forebay above a dam Oklahoma Master Conservancy District oxygenation of the hypolimnion of a lake or in-lake pretreatment of raw drinking partnered with the Oklahoma Water without disrupting the stratified layers water near the intake. The inlet and outlet Resources Board to design and monitor an of water. If it is desirable to oxygenate hoses of the SDOX can be arranged to SDOX unit at the lake’s deepest location

Summer 2010 / LAKELINE 15 near the dam (maximum depth of 50 the cities of Norman, Del City, and 50 feet in the hypolimnion and to capture feet). The SDOX will be used to prevent Midwest City, Oklahoma for use as a the effect of SDOX operation. Funding for the lake’s hypolimnion from becoming potable water supply. Once the SDOX is this effort was derived from the Oklahoma anoxic throughout the summer months installed, water quality monitoring will Water Resources Board’s state water and without disrupting the lake’s natural occur for two years in order to determine wastewater infrastructure stimulus money thermocline. It has been determined that nutrient dynamics (including sediment obtained through the American Recovery the seasonal anoxia that occurs each phosphorus flux) and trophic response. and Reinvestment Act of 2009. summer is changing the lake’s chemistry The data gathered will be compared to The advantages of SDOX for DO in a way that the eutrophic condition information gathered over the past ten addition to lakes include: is exacerbated. Implementation of the years at the same sites (Figure 4) in order • Cost effective DO delivery to shallow SDOX is targeted to not only improve to fully document improvements to water and/or warm lakes water quality in the lake for biota but quality in the lake. A critical aspect of the also to reduce the costs of processing monitoring will be dissolved oxygen with • Small footprint of DO delivery system the water as a drinking water source. depth. Sample sites and frequency have • Automated control of the DO delivery Lake Thunderbird water is treated by been increased to target a depth of 40 to rate in response to a DO sensor so only the minimum operating costs are incurred • Targeting of DO addition to a specific layer in the thermocline without mixing the temperature-stratified layers • Addition of DO with minimal disturbance of sediments at the bottom of the lake • Addition of dissolved oxygen beneath a layer of ice

Figure 3. (Left) GoogleTM image with markers showing location of deployment and buoys for measuring DO addition in Lake Brittany. (Bottom) Graphic of the DO plume formed at 30 feet of depth after five days of SDOX injection. DO addition was below the thermocline and did not disrupt temperature stratification.

16 Summer 2010 / LAKELINE • Targeting of optimum DO conditions and engineering patent applications, publications, and for fish and other aquatic species (5 design of fluid-flow and other documentation. She specializes in mg/L or above) thermodynamic systems formulating and maintaining collaborative has led to the creation relationships with experts in both research • Promotion of a shift to efficient of controlled oxygen and industry and in incorporating multiple and reduced-odor aerobic bacterial transport systems in viewpoints and addressing specific digestion of excess dissolved organics natural waterways. His audiences in written documentation. • Prevention of nocturnal DO sags in interests have been She can be reached at amccain@virtual- algae-laden waters extended to include incubation.com. • Reduced toxicity (and/or prevention of the design of efficient dissolved oxygen formation) of dissolved contaminants and ozone injection systems for use in Grace Richardson has (iron, manganese, and hydrogen natural waterways, industrial and municipal been an applications sulfide) via oxidation and precipitation wastewater, and aquaculture facilities. His engineer for e-mail is [email protected]. BlueInGreen since For more information on SDOX 2008, when she systems, please contact Scott Osborn Anna McCain has been finished her degree in at BlueInGreen, LLC or e-mail scott. the technical writer/ biological engineering [email protected]. liaison for BlueInGreen with a focus on since 2004. Mrs. McCain ecological restoration Scott Osborn is president of BlueInGreen, provides research and sustainable aquaculture. She currently LLC and co-inventor of the patented SDOX and technical writing works on the design and implementation technology. Dr. Osborn’s in-depth knowledge support throughout of BlueInGreen’s developed and beta of respiration processes, oxygen transport the development of technologies to further the improvement dynamics, numerical modeling techniques, proposals, reports, of water quality for human consumption and environmental restoration. She can be reached at grace.richardson@blueingreen. com. x

Figure 4. Bathymetric map of Lake Thunderbird, showing historical and future testing sites. An SDOX unit will be deployed near Site 1 and water quality testing will document the improvements to water quality over a two-year period. The raw water intake is located near Site 4.

Summer 2010 / LAKELINE 17 New Approaches

The FHAB Problem & U.S. Policy

H. Kenneth Hudnell and Joseph Eilers

Freshwater Harmful Algal Bloom (FHAB) Suppression in water, near surface, and underwater Nutrient-enriched Water Bodies through Solar-powered components. Solar panels, a low-voltage, Circulation (SPC) high-efficiency brushless motor, an electronic control box, and accessories utrophication, the process water-body management approaches were mounted on an above-water frame. through which the flux of based on ecological principals are needed A distribution dish, impeller, and battery growth-limiting nutrients to suppress FHABs in the near term and were suspended from the frame just below Efrom watersheds to receiving support the stressed ecological processes the surface. A 0.914 m diameter, flexible, waters stimulates excessive plant that historically maintained good water intake hose was attached to the frame growth, continues to increase in U.S. quality. Environmentally sustainable at the base of the impeller. A steel plate freshwaters. Analyses of data from the approaches to within water-body suspended 0.305 m beneath the intake U.S. Environmental Protection Agency’s management can complement the long- caused water to be drawn in radially (EPA) first eutrophication survey term effort to limit nutrient influx through with near-laminar flow. Adjustments of conducted in 1972 indicated that 10-20 watershed management and help ensure a chains attached to the plate and frame percent of all U.S. lakes and reservoirs sustainable supply of usable freshwater. controlled intake depth. Additional chains were eutrophic (Gakstatter and Maloney attached to the frame and two moorings 1975). The Agency recently reported Study Description and maintained the spatial position of the that over 50 percent of all U.S. lakes SPC Technology unit. The impeller rotated continuously and reservoirs are currently eutrophic or A recent investigation indicated that at 60 RPM (80 RPM in newer units) hypereutrophic (EPA 2009), indicating SolarBee® Inc.’s technology of solar- unless prolonged periods of low light an alarming rate of increase. The powered circulation (SPC) suppressed incidence caused the electronic controller sustainability of freshwater ecosystems FHABs in nutrient-enriched water bodies to reduce the RPM or deactivate the is imperiled by the increasing incidence by targeting the FHAB stimulatory factor system temporarily. The units transported and durations of freshwater harmful algal of quiescent, stagnant water (Hudnell et approximately 37,850 L/min of water to blooms (FHABs) in eutrophic water al. 2010). The SPC suppression of FHABs the surface. Approximately 11,355 L/min bodies. FHAB cells, predominantly greatly reduced the need for algaecide of direct flow ascended through the hose, cyanobacteria (aka blue-green algae), applications and promoted a well- and another 26,495 L/min of induced and their highly potent toxins adversely balanced planktonic assemblage. flow ascended external to the hose. impact aquatic ecosystems and pose Personnel at three municipal-water Water departed from the units radially at serious risks for human and animal utilities collected limnological data low velocity, both above and below the health and economies. More than seven before and during SPC deployment for distribution dish. The outflow mixed with decades of soil conservation policy and FHAB control. The study sites were other surface currents to redistribute water approximately three decades of watershed Crystal Lake, Des Moines, Iowa (Figure across the treatment area. management policy, each with current 1); East Gravel Lake # 4 (EGL4), The intake depth was set at the base federal expenditures of greater than $5 Thornton, Colorado (Figure 2); and Lake of the photic zone for FHAB suppression, billion annually, failed to reverse the Palmdale, Palmdale, California (Figure 3). usually just above the thermocline. trend of increasing eutrophication (EPA Reservoir, data collection, and treatment Only the epilimnion was circulated. The 2009a). Within water-body management parameters are shown in Table 1. The thermocline was left intact to prevent of eutrophication and FHABs has not data collection and analysis methods are hypolimnetic nutrients from entering taken a prominent role in federal policy. described in detail in the original article the photic zone and further stimulating Chemical approaches to FHAB control published in Harmful Algae (Hudnell et FHABs. have predominated at local levels, but the al. 2010). available evidence indicates that chemical Each SolarBee®, Inc., SB10000 unit Limnological and Algaecidal Data approaches may not be environmentally (Figure 4) consisted of three pontoons Longitudinal cyanobacterial-density sustainable (Hudnell 2010). Within that provided buoyancy for above data are shown in Figure 5. Peak cell

18 Summer 2010 / LAKELINE 1 2

Figures 1-3. Aerial views of the three test sites with influents, effluents, sample collection sites, SPC units, scale, and direction indicated.

density declined sharply during SPC in Crystal Lake, where algaecides were 3 never used. Mean cell densities declined each year during SPC, indicating that the strength of suppression increased over time. Similar results were obtained at EGL4. Algaecides were applied 1-2 times per month prior to SPC due to cyanobacterial-cell seeding from the influent, but usage declined to 1-2 per year during SPC. Peak cyanobacterial density was held to about 2,000 cells/ ml in Lake Palmdale prior to SPC by applying over 26,000 kg/yr copper sulfate. Applications declined to <4,000 kg/yr during SPC. Peak cyanobacterial density increased during the first year of SPC, but was significantly below the pre-SPC level the second year. Nutrient concentrations were consistent at all sites throughout the study. Total nitrogen and phosphorus concentrations in Crystal Lake zooplankton benefited from the declines responded vigorously to the availability of occasionally peaked at approximately in cyanobacterial density, as well as edible algae in Lake Palmdale. 18 and 8 mg/L, respectively. Nitrate and reductions in copper sulfate usage of total phosphorus levels reached 10 and approximately 85-92 percent in Lake Discussion 1.3 mg/L in EGL4, and 6 and 0.22 mg/L Palmdale and EGL4. As shown in Figure A water body, like a human body, in Lake Palmdale on several occasions, 6, chlorophyte densities rebounded needs good circulation to function respectively. robustly in Crystal Lake, mean and peak properly. The data demonstrated that SPC Populations of chlorophytes diatom densities increased significantly of the epilimnion strongly suppressed (aka green algae), diatoms, and in EGL4, and zooplankton populations FHABs even in nutrient-enriched

Summer 2010 / LAKELINE 19 Table 1. Reservoir, Data Collection, and Treatment Parameters.

Crystal Lake EGL 4 Lake Palmdale

Algaecides Used No Yes Yes Surface Area (km2) 0.26 0.47 0.89 Maximum Depth (m) 7.6 10.7 7.6 Mean Depth (m) 3.0 7.6 5.5 Volume (km3) 7.65x10-4 3.53x10-3 4.90x10-3 Hydraulic Residence Time (days) 40 270 91 Data Collection Period March-December 2005-2008 January-December 2001-2007 January-December 2002-2004 SPC Initiation Date March 2006 April 2003 November 2002 # SPC Units 2 3 6-7a Surface Area km2/SPC unit 0.13 0.16 0.15-0.13a Mean Intake Depth (m) 2.4 6.7-4.3b 4.6 Water Volume Circulated (km3) 6.1x10-4 3.1x10-3-2.0x10-3b 4.1x10-3 Water km3 Circulated/SPC unit 3.05x10-4 1.04x10-3-6.67x10-47b 6.82x10-4-5.85x10-4a SPC Circulation Rate (km3/day) 5.5x10-2 5.5x10-2 5.5x10-2 Total Circulation Rate (km3/day) 0.11 0.17 0.33-0.39a Turnover Duration (days)c 5.6 19.0-12.2b 12.4-10.6a

a A seventh SPC unit was installed in June 2003. b Water intake depths were varied as the reservoir surface elevation and water clarity varied over time. c The duration required for the SPC units to circulate all the water between the surface and mean intake depths one time. waters. Suppression of FHABs within the approximately 0.15 km2 (35 acre) treatment zones indicated that continual SPC radial, near laminar-flow intake, upflow and outflow merging with natural surface currents combined to create long- distance circulation of the epilimnion. The evidence indicated that circulation of the otherwise quiescent, stagnant water supported ecological processes that help maintain good water quality. Although the mechanism(s) through which SPC suppressed FHABs remains unknown, the scientific literature on cyanobacterial ecology and circulation indicate five plausible mechanisms. Circulation may (1) interfere with cyanobacteria’s ability to optimize position in the water column through buoyancy control to meet nutrition and sunlight requirements; (2) distribute Figure 4. One of the SPC units installed at Crystal Lake. The unit diameter from pontoon tip to pontoon tip is approximately 5 m. Photo courtesy of Christopher Jones, Des Moines Water Works. non-motile cyanobacterial pathogens, such as cyanophage, viral particles, fungi and lysing bacteria, throughout making it less available to cyanobacteria, ecological conditions may cause some the epilimnion, greatly increasing their which have a greater iron requirement mechanisms to take a more prominent contact rate with cyanobacteria; (3) than do chlorophytes, and; (5) promote a role in suppression than others at different enable non-motile, smaller, and more robust zooplankton population that limits times and locations. rapidly reproducing bacteria and algae to the cyanobacterial population through SPC did not eliminate all outcompete cyanobacteria for nutrients grazing. The process through which SPC cyanobacterial cells from the reservoirs, and/or iron or other micronutrients; suppresses FHABs may be multifactorial, nor was suppression apparent during (4) enhance the oxidation rate of iron, and variations in environmental and the first FHAB season in Lake Palmdale

20 Summer 2010 / LAKELINE posed by a dwindling supply of usable freshwater to aquatic ecosystems, health, and economies. The full article published in the scientific journal, Harmful Algae, can be downloaded for educational purposes from http://science.solarbee.com/, as can be the Toxicon article. For additional information, contact Dr. Hudnell at (919) 932-7229 or [email protected].

References (additional references are available in the Harmful Algae journal articles) Clean Water America Alliance. 2009. A call to action: The need for an integrated national water policy – The Clean Water America Alliance’s National dialogue report. Washington, DC, 15 p. EPA. 2009. National Lakes Assessment: A Collaborative Survey of the Nation’s Lakes. U.S. Environmental Protection Agency, EPA 841-R-09-001, Washington, DC, p. 101. EPA. 2009a. Clean water state revolving fund programs: 2008 annual report. U.S. Environmental Protection Agency, EPA 841-R-07-001, Washington, DC, p. 24. Gakstatter, J.H. and T.E. Maloney. 1975. Potential impact of a detergent phosphorus ban on eutrophication in selected American lakes and streams. U.S. Environmental Protection Agency, Corvallis, OR, p. 19. Hudnell, H.K., C. Jones, B. Labisi, V. Lucero, D.R. Hill, and J. Eilers. 2010. Freshwater harmful algal bloom (FHAB) suppression with solar powered circulation (SPC). Harmful Algae, 9:208-217. Figure 5. Cyanobacterial densities before and during SPC. Cyanobacterial monitoring in Lake Hudnell, H.K. 2010. The state of U.S. Palmdale was suspended in mid-2004. freshwater harmful algal blooms assessments, policy and legislation. when algaecide usage declined by about of useable freshwater. Within water- Toxicon, 55:1024-1034. 85 percent. However, the magnitude of body management technologies such suppression increased over time, and as SPC are needed to complement Dr. H Kenneth well-balanced planktonic assemblages watershed management if water quality Hudnell served as a indicated improved function of ecological is to be improved in the near term. neurotoxicologist at the processes. This evidence indicates Ecologically based and environmentally U.S. EPA for 23 years, that SPC is an ecologically based and sustainable approaches to solving water conducting studies environmentally sustainable approach quality problems should take a central of the human health to within water-body management that role as we move toward developing effects from exposure suppresses FHABs in the near term. an integrated national water policy to environmental The stress on ecological processes (Clean Water America Alliance 2009). pollutants with a focus on in eutrophic water bodies must be Innovative approaches to within water- biotoxins. Ken led an interagency committee reduced to ensure a sustainable supply body management can reduce the risks to address a Congressional mandate

Summer 2010 / LAKELINE 21 concerning FHABs. Ken is vice president and director of science at SolarBee Inc., and an adjunct professor in the University of North Carolina’s Institute for the Environment. He currently conducts research on environmentally sustainable approaches to within water-body management in fresh, potable, waste, storm and industrial waters. Ken is working with the Clean Water America Alliance to bring about an integrated National water policy.

Joe Eilers has worked as a limnologist in Oregon for the last 22 years. He is a certified lake manager, a registered professional hydrologist, and a certified fisheries biologist. He conducted the water quality investigations for the managing agencies leading up to and following the Diamond Lake Restoration Project. Joe owns MaxDepth, Inc. in Bend, Oregon and is a representative for Solar Bee, Inc. x

Figure 6. Beneficial-plankton densities before and during SPC. Zooplankton monitoring in Lake Palmdale was suspended in late 2003.

22 Summer 2010 / LAKELINE New Approaches

Diamond Lake Recovery – Again

Joe Eilers and Holly Truemper

Lake Description the balance used to stock lakes throughout fishing. In this same year, ODFW began iamond Lake is a stunningly the state. Although two permanent streams the practice of supplementing the stocking beautiful 1,226 ha lake located enter Diamond Lake, both are derived of fingerlings with legal-sized trout to just 18 km north of Crater Lake. from spring water so cold that they don’t maintain a fishery. The initial attempt DIt is flanked by Mt. Thielsen on support much trout reproduction. by ODFW to proceed with a rotenone the east and by Mt. Bailey on the west. project, much as was conducted in the In a draft of the park boundary, Diamond Collapse of the Trout Fishery 1950s, was aborted when opposition Lake was included with the national park This scenario of trout egg collection/ to the treatment caused the project to to provide a complementary experience to rearing/restocking worked well until the be shelved. However, opposition to a the breathtakingly beautiful, but difficult 1940s, when fish biologists noticed that repeated rotenone treatment quickly to touch Crater Lake. However, the final growth, survival, and harvest of rainbow dissipated after the summer of 2001 when wrangling resulted in Diamond Lake trout began to mysteriously decline. the lake was hit by an intense bloom of staying with the Umpqua National Forest Multiple hypotheses were investigated Anabaena. In addition, with zooplankton and developing into a more intensive until the biologists realized that the trout grazers being eaten by the tui chub, there recreational resource than might have were being out-competed for their prey, was little control of the algae. However, occurred otherwise. There is a large zooplankton and benthic invertebrates, it was found that the excretion of nitrogen privately run lodge, 445 Forest Service by an invasive small minnow, the tui and phosphorus by the large population campsites in several campgrounds, and chub (Gila bicolor). The tui chub was of tui chub provided the primary 102 private cabins on land adjacent to believed to have entered the lake via nutrients to sustain the cyanobacteria the lake leased from the Forest Service. live bait dumped into the lake after a blooms. With lake closures from the This lineage factors into its current days’ fishing. Biologists tried netting cyanobacteria blooms, recreational use management challenges. the chub and using spot-treatments of declined dramatically and economic Diamond Lake was formed by tephra rotenone until they concluded that they impacts to the local economy took their erupting from Mt. Mazama (now the site would have to eradicate the tui chub. The toll. It only took several years of the of Crater Lake) about 6,700 years ago. original Diamond Lake recovery project blooms before resistance to the proposed The ash and volcanic debris impounded consisted of dredging a channel to lower rotenone treatment faded and planning a stream in a mountain meadow leaving the lake stage by 2.4 m and applying for a project at the lake resumed with the a lake that was about 6 m deeper than powdered rotenone in September 1954. goal of restoring the lake to fishable and its current condition. The lake remained The lake was restocked and fishing was swimmable. fishless until about 1910 when trout opened up again in spring 1956 and trout were first introduced. The shallow lake fishing continued successfully for over The Rotenone Treatment three more decades. Additional details on In the 1950s, project planners didn’t (Zmax= 14.8 m; Zmean= 6.9 m) supported a productive benthic fauna and probably the lake history are available elsewhere have to contend with environmental a high density of large cladocerans (Eilers et al. 2001; 2007). impact statements (EISs). Following and copepods often found in many In 1992, fish biologists once again completion of this tome for the current fishless lakes in the Cascade Range. found tui chub in the lake. Although project, plans began for a repeat of the The introduced trout grew rapidly and it was intensely disappointing to see rotenone project (Umpqua National Forest for a period this was one of the largest their nemesis in the lake again, it also 2004). With relatively modest changes fish egg collection stations in the region, served to explain the decline in the to the original treatment design, the 20th with collections of over 18 million eggs. trout fishery, which in retrospect, was century version of the Diamond Lake This bounty allowed the Oregon Game beginning to be expressed in the late Restoration Project was launched. The Commission, predecessor agency to the 1980s. From 1992, when the tui chub original canal was re-dredged to allow for Oregon Department of Fish & Wildlife were first encountered until 2001, the the drawdown that served three functions: (ODFW), to rear 1 million of the young only obvious sign that something was (1) reduce the lake volume by 40 percent, trout for planting back into the lake with clearly wrong with the lake was the poor thus reducing the amount of rotenone

Summer 2010 / LAKELINE 23 required; (2) allow for water to be held spray the liquid rotenone plied the shallow meter, exceeded densities of over 75,000 in the lake following the treatment, waters along the shoreline (Figure 2). individuals per cubic meter by the end thus allowing the rotenone to degrade Finally, nine large pontoon boats built for of June 2007. The biomass of benthic before water was released downstream; the project applied rotenone behind their organisms showed a similar response and (3) reduce the area of the lake with crafts (Figure 3). In the end, 32.6 metric with numbers increasing from 2.3 g/m2 macrophyte coverage and thus increase tonnes of liquid rotenone and 48.6 metric before the treatment to 22.5 g/m2 in 2007, the likelihood for a complete kill of the tonnes of powdered rotenone were applied 18.8 g/m2 in 2008, and 38.3 g/m2 in 2009. fish (Figure 1). The water was drawn to the lake to achieve a concentration Species of benthic macroinvertebrates, down through the new headgate over a of 0.11 ppm of active ingredient in the which had been absent for years, returned nine-month period to minimize hydraulic water column. All fish cages deployed rapidly, although new benthic species overload to the outlet stream. Tui chub throughout the lake indicated that the kill are still being observed annually. Fish were netted from the lake in the summer had been complete. growth returned to phenomenal levels of 2006 to reduce the additional nutrient with growth rates of 4.3 cm/mo in the first load from the mass of fish that would Lake Response to Rotenone summer following the treatment, 4.7 cm/ decay in the lake following the treatment. The initial response was mo in 2008, and 3.4 cm/mo in 2009. The This resulted in removal of 30.8 metric anticlimactic, although weather conditions fish were fat, creels were full, and local tonnes of tui chub. Finally, the rotenone were favorable for mixing the rotenone cash registers rang announcing resurgence was applied on September 13-15, 2006. throughout the lake. A relatively small of the local recreation-based economy. The first applications started by metering number of fish struggled to the surface The Anabaena that had plagued the liquid rotenone at drip stations into the and expired, but for the most part, lake since 2001 virtually disappeared, two tributaries to drive any tui chub that nothing much happened. Several days replaced by low densities of might have wandered into the cold inlet later fish began to decompose, float cryptomonads and diatoms. Secchi disk streams. The next sequence involved to the surface, and accumulate on the transparency, which before treatment use of applicators on foot equipped with shoreline, revealing the true magnitude averaged about 1.6 meters in the summer backpack units dispersing liquid rotenone of the dominance of the tui chub (Figure prior to treatment, reached a maximum along the shoreline. Simultaneously, 4). During post treatment, another 15.9 of 12.5 m in June 2007 (Figure 6). Light smaller boats equipped with pumps to metric tonnes of fish were raked up and now reached the entire lake bottom. disposed offsite. However, many As a consequence, aquatic plants (both of the dead tui chub simply macrophytes and filamentous algae) decayed in the lake, fueling a colonized some areas of the lake that vigorous Anabaena bloom that formerly were light-limited. Epilimnetic continued despite the declining pH, which had averaged 9.5 in 2006, lake temperatures (Figure 5). declined to an average of 8.4 in 2007 and Rotenone and its immediate 7.8 in 2008. Chlorophyll concentrations, degradation product rotenolone which had averaged 15.3 ug/L prior to were no longer detectable about treatment, now averaged 2.7 ug/L in eight weeks after treatment, 2007 and 7.8 ug/L in 2008. The lake making it possible to open was meeting water quality standards for the headgate. The process of the first time in years. All this occurred refilling the lake began and was without significantly altering the nutrient finally achieved in July of 2007. concentrations in Diamond Lake. What Conditions in the lake caused had changed was the rate of nutrient concern as oxygen continued to re-supply made possible by the abundant be consumed in waters below 6 tui chub. Diamond Lake became the only m and cyanobacteria still thrived lake to meet its TMDL targets by reducing below the thickening ice layer. the internal loading rate associated with Upon ice-out, the ammonia waste products produced by the 200 that had accumulated under metric tons of fish that had overwhelmed the ice was mixed throughout the lake (http://www.epa.gov/owow/ the water column and fueled nps/Success319/state/or_diamond. a major Synedra (diatom) htm). Diamond Lake was only one of bloom. The bloom dissipated many lakes in Oregon suspected of not over the next several weeks meeting water quality standards because as Daphnia pulicaria, a very of the overabundance of planktivorous or large cladoceran, returned omnivorous fish. Reduction of watershed Figure 1. Diamond Lake with Mt. Thielsen in the in abundance. Populations loading of nutrients will do little to background. Lake elevation was being checked as the of Daphnia, which had been improve water quality conditions in these drawdown proceeded in 2006. Photo by Joe Eilers. reduced to single digits per cubic lakes.

24 Summer 2010 / LAKELINE ($0.38 M). Based on the analyses conducted for the EIS, the economic benefits from the project were realized in the first two years following the project. However, not all of the post-project results were rosy. Although the 2006 eradication of tui chub was a success, within the first year, ODFW biologists found another invasive minnow in Diamond Lake. The golden shiner (Notemigonus crysoleucas) population has not exploded as did the tui chub and previous history in Diamond Lake with this species suggests that it will not pose a problem. Monitoring effects continue at Diamond Lake to document continued recovery and to ensure that the current trout-stocking program does not interfere with its recovery. Figure 2. Crews spray liquid rotenone into the shallow areas to ensure no areas went untreated The future of all managed lakes during the treatment. Photo by Oregon Department of Fish & Wildlife. requires constant attention. In the case of Diamond Lake, extra vigilance is required because history has shown that it can be turned into a cyanobacterial quagmire with the inadvertent or intentional introduction of the wrong species of fish. To minimize a repeated invasion of tui chub or similar-behaving species, agencies have teamed up to work on aquatic invasive species and have posted boat ramps reminding fishermen to avoid the use of live bait, cash rewards have been offered to identify anyone attempting to introduce live fish into the lake, and a boat washing station has been installed to allow boats to be cleaned prior to launching. Hopefully, these and other actions will forestall what some opponents of the rotenone project believe is inevitable . . . namely, that the cycle will be repeated. For now, the Diamond Lake Restoration Project has returned the lake to a bountiful trout fishery and a gorgeous blue gem in the Cascades.

References Eilers, J.M., C.P. Gubala, P.R. Sweets and D. Hanson. 2001. Effects of fisheries management and lakeshore Figure 3. Boats follow prescribed GPS-driven paths to apply the rotenone. The light-colored paths development on water quality in represent application of powdered rotenone and the dark paths indicate application of liquid rotenone. The red dye at the entrance of Silent Creek was used to help guide shoreline-based Diamond Lake, Oregon. Lake and application in this critical mixing zone. Photo by Joe Eilers. Reservoir Management, 17:29-47. Eilers, J.M., D. Loomis, A. St. Amand, A. Vogel, L. Jackson, J. Kann, B. Project Costs and of the rotenone and its application. Other Eilers, H. Truemper, J. Cornett and R. Looking to the Future major costs included the EIS ($0.7 M), the Sweets. 2007. Effects of repeated fish The tally for the entire project canal dredging and new headgate ($0.7 introductions in a formerly fishless through 2008 was about $5.2 million, of M), studies and monitoring ($0.65 M), lake: Diamond Lake, Oregon, USA. which $1.4 million was the actual cost and pre-/post-fish netting and collection Fundamental and Applied Limnology

Summer 2010 / LAKELINE 25 Figure 4. Dead tui chub float across Diamond Lake on September 18, three days Figure 5. Diamond Lake turns green from Anabaena on following the treatment. Photo by Joe Eilers. October 2, two weeks following treatment. The intensity of the cyanobacteria was somewhat surprising given the declining lake temperatures. Photo by Joe Eilers.

(Archiv für Hydrobiologie), 169 (4):265-277. Umpqua National Forest. 2004. Diamond Lake Restoration Project. Final Environmental Impact Statement. Douglas County, Oregon. 580 p. + appendices.

Joe Eilers has worked as a limnologist in Oregon for the last 22 years. He is a certified lake manager, a registered professional hydrologist, and a certified fisheries biologist. He conducted the water quality investigations for the managing agencies leading up to and following the Diamond Lake Restoration Project.

Holly Truemper worked for many years on Lake Michigan with invasive species. She has worked for Oregon Department of Fish & Wildlife in Roseburg since 2003 and was a biologist Figure 6. An aerial view of the north end of Diamond Lake on June 20, 2007. The now-submerged on the Diamond Lake canal is viewed as a line extending into the lake. The dark zones represent macrophytes. Photo by Restoration Project team. x Mari Brick.

26 Summer 2010 / LAKELINE New Approaches

P. parvum Bloom in a Nevada Reservoir

Steve Weber and Jeff Janik

Preliminary Report on Aquatic Food Web Impacts from a Toxic Haptophyte

armful algal blooms (HABs) in U.S. coastal and freshwaters have received much greater Hattention in recent decades. While blooms from bluegreen algae (cyanobacteria) are more widely recognized, a member of the haptophytes, Prymnesium parvum, produces toxins that can kill fish and other aquatic biota, resulting in substantial water quality degradation. This article reports the first bloom of P. parvum in Nevada and impacts on fish, zooplankton, and quagga mussels in Lake Las Vegas, a man-made Figure 1. Lake Las Vegas area map. lake near Las Vegas (Figure 1). evaporation losses of about 0.002 km3 Prymnesium parvum Lake Las Vegas annually (Weber 2006). P. parvum is a haptophyte or golden Lake Las Vegas is a 130 ha warm Lake Las Vegas water chemistry alga with two flagella and a unique monomictic reservoir located adjacent is influenced by a number of natural flagellum-like organ called a haptomena to the Lake Mead National recreational and anthropogenic sources. Natural (Figure 3). The species belongs to the area boundary in Henderson, Nevada. influences such as flood events discharge same group as the non-toxic and common Construction began in 1989 with a 1.6 m periodically into the reservoir and species in lakes, reservoirs, and ponds, long earthen dam within the Las Vegas influence water chemistry and plankton Chrysochromulina parva. P. parvum Wash channel (Figure 2). The wash flows communities. Depending on the specimens in Lake Las Vegas were about of about 300 c.f.s. are bypassed under magnitude of these events, the change 10 µm x 6-7 µm and identified and the reservoir via two 2.13 m diameter may be short-lived or last for several years enumerated with an inverted microscope concrete pipes. The bypass was designed when the lake’s volume is completely under phase contrast microscopy in to keep high-nutrient, low-quality replaced or flushed as in a July 1999 event Lugol’s preserved samples. runoff water out of the lake. Only in when 0.06 km3 passed through the lake. The species was first reported in storm events of greater than three-year The reservoir is a unique urban the U.S. in the 1980s and has been frequency does the Wash water flow into lake providing recreation and irrigation found in Texas, Arizona, New Mexico, the reservoir. Construction of the dam and storage for a large master-planned Colorado, Wyoming, North Carolina, its three spillways was completed in May community, including three 18-hole golf South Carolina, Georgia, Arkansas, and 1991 and filling began with 0.004 km3 courses. The management and staff of Alabama, and likely others. P. parvum of Lake Mead water. At full elevation, the reservoir conduct monthly water has been reported at concentrations the reservoir is 3.2 km long and one quality. monitoring of physical, chemical, exceeding 100,000 cells/mL and blooms mile wide. The maximum depth is 43 m and biological constituents. While may occur in inland waters at salinity with average depth 10 m and an average management of the reservoir has changed of 1-2 psu with lower growth at < 1psu. storage capacity of 0.013 km3. Untreated since 1991, water quality monitoring and Blooms in low salinity coastal and inland Lake Mead water is the primary source analytical methods have been consistent waters have been reported worldwide. The of makeup water to the reservoir with since the reservoir was constructed. species inhibits the growth of competing

Summer 2010 / LAKELINE 27 zooplankton for available food and resources. P. parvum, as in most algae, produces energy through photosynthesis, but in addition is mixotrophic and capable of using both inorganic and organic and dissolved nutrient sources. Its ability to ingest bacteria and other algae is known as “phagotrophy.” The species’ ability to persist in both nutrient limited environments as well as nutrient excess systems further enhances its competitive advantage. Unlike some cyanobacteria that can fix nitrogen from the atmosphere during periods of nutrient depletion, P. parvum can consume phytoplankton, zooplankton, and bacteria to meet energy needs. Toxicity may be influenced by environmental conditions; phosphorus and nitrogen limited growth are among the factors that may promote toxin production. Other conditions such as pH, salinity, and temperature have also been found to influence the toxicity of the P. parvum. These toxins can serve to directly remove algae competitors of P. parvum for nutrients and create an environment where the decaying organic matter and subsequent bacterial colonies provide particulate nutrient sources for P. Figure 2. Lake Las Vegas map. parvum’s mixotrophic mode of nutrition.

dramatically since 2001. While fish are Short History of the most visible casualty of a P. parvum Algal Introductions bloom, the toxins released kill other Since the lake began filling in gill-breathing organisms, invertebrates, 1991, reservoir managers and staff planktonic algae, and bacteria. have conducted extensive water quality The appearance of P. parvum is a monitoring of physical, chemical, and potential challenge to lake managers. The biological constituents. This record species is equipped with an arsenal of provides a unique data set especially of toxins; cytotoxiins, ichthyotoxicins, regarding the plankton community and neurotoxicins, substances that are where the same phycologist (Janik) and antibacterial and allelopathic, acting methods have been utilized for nearly 20 to inhibit the growth or even kill other years. The phytoplankton composition is Figure 3. Photomicrograph of Prymnesium phytoplankton, zooplankton and fish. strongly influenced by inflow from Lake parvum at 100x magnification. Photo by Karie These toxins provide P. parvum with a Mead and the Colorado River, the primary Holtermann, Metropolitan Water District of southern competitive advantage over competing source of water for the lake. For example, California). algal species for nutrients and may during the past ten years, a number of also reduce their grazing losses from species have been introduced, likely from algae, especially cyanobacteria and zooplankton and planktivorous fish, Lake Mead source water inflows. These dinoflagellates and completely suppresses enabling it to completely dominate the species may dominate for a few seasons diatoms. phytoplankton community under suitable and often then become minor components In Texas, 12 million game and environmental conditions. of the algal community. An example is threatened fish were killed in various The complex life cycle, physiology, the green alga, Pyramichlamys dissecta. water bodies from 1985-2001 with an and ecological niche requirements and This species was observed in 1996, 1997, estimated value of tens of millions of strong survival attributes of P. parvum 1998, and 2001 in the inner Las Vegas dollars. The incidence of P. parvum give this species a strong advantage to Bay. During 2001, P. dissecta’s population blooms in Texas has increased out-compete other phytoplankton and exploded and expanded into an extensive

28 Summer 2010 / LAKELINE algae bloom that persisted for nearly six Table 1. A Comparison of Biological Diversity Before and After the Introduction of P. parvum. months. P. dissecta became the dominant species in Lake Las Vegas soon after the Jan.-Feb. 2009 Jan.-Feb. 2010 Lake Mead bloom and has persisted at low densities until approximately 2006 Phytoplankton and is now found in low numbers. The Assemblage Rhodomonas minuta, P. parvum (99% biomass) cyanobacterium and toxin producer, Cryptomonas spp., Cylindrospermopsis raciboskii was first Cyclotella spp., reported in Lake Las Vegas in July 2007 Chrysochromulina parva and has remained a notable component 1 No. Common species 4-7 1 of the late summer and fall assemblage. In January 2007, quagga mussels were Biomass (mg/m3) 200-400 15,000-20,000 first reported in Lake Mead. Within a few months, quagga mussels were reported Zooplankton in several of the golf course ponds in the resort supplied by Lake Mead via Lake Assemblage Mixed: Daphnia, copepods, Copepod nauplii Las Vegas. The discovery of P. parvum rotifers in December 2009 is the latest and likely the most significant of the introductions 2Taxonomic richness 4-6 1 on the lake plankton ecology. While its presence at this time is unconfirmed in Abundance (per L) 25 - 75 0.5 - 2 Lake Mead, the species has been reported Quagga Mussels Present Absent in low abundance in the downstream reservoir, Lake Havasu (personal Fish (dead) /day 0 1-697 (Avg. 91) communication, Karie Holtermann, 2010, Metropolitan Water District of southern Average Secchi (m) 4.9 1.0 California). 1 Common species – contributing 5% or more to biomass. The Great Competitor: 2 Taxonomic richness – total number of taxa identified. Impacts to the Food Web Phytoplankton. P. parvum was first identified in Lake Las Vegas P. parvum jumped to more than 80,000 been observed. In 2007, quagga mussels in December 2009. The winter cells/mL and peaked at 96,000 cells/mL were found in Lake Mead, Clark County, phytoplankton community is typically on March 11. P. parvum has maintained Nevada and subsequently spread to Lake characterized by relatively low biomass bloom levels to the last sample collected Las Vegas. Since the identification of (less than 400 mg/m3) and composed of on April 13, 2010. P. parvum in Lake Las Vegas, quagga a mixed assemblage of cryptophytes, mussels have not been seen on pelagic diatoms, and the commonly occurring Zooplankton. The zooplankton substrate samplers that were previously Chrysochromulina. parva (Table 1). The community during January to April heavily colonized. In addition, golf course lake managers were immediately notified is typically characterized by rotifers, maintenance staff reported the shedding of the potential for fish kills when P. copepods, and cladocerans (Daphnia of quagga mussels from within their parvum was first identified. In the Lake pulex) with total density from 25 to irrigation systems that receive water from Las Vegas Early Detection Monitoring 75/L, When P. parvum abundance Lake Las Vegas. Program, samples are analyzed within reached 50,000 cell/mL in mid-February, seven days of collection with results and zooplankton were abruptly reduced in Fish. Fish mortality was first recommendations immediately provided about two weeks from 60/L to 1/L with observed approximately 30 days after to lake management. The presence of the only copepod naulpii remaining. At the the first occurrence of P. parvum in species triggered higher frequency weekly time of this article, P. parvum remained December. Since the first dead fish was sampling and a factsheet was prepared at more than 70,000 cell/mL and copepod found, maintenance workers collected and distributed to lake stakeholders. nauplii were the sole representative of dead fish every day with an average of 91 Cell abundance of P. parvum remained zooplankton at less than 1/L. fish collected daily with a range of one at about 1000 cells/mL until late January to 697 removed over a 58-day period. 2010, when inflows from a large storm Quagga mussels. Southhard et al. These statistics are skewed so that during event substantially elevated the total P (2010) reported that P. parvum might the peak biomass of P. parvum, a greater concentration in the lake to greater than have influenced the decline of Asiatic number of dead fish were observed with 30 µg/L. Abundance in mid-February clams, Corbicula fluminea, in the Pecos significantly fewer observed after the peak then increased to 35,000 cells/mL (Figure River system in Texas. Similar impacts of the bloom. 4). Within two weeks, in early March, to mollusks in Lake Las Vegas have

Summer 2010 / LAKELINE 29 100 system treatments are more easily applied to ponds or lakes that are less than 25 acres in area. Larger lakes (>100 acres) 80 typically have more complex limnological dynamics and, in turn, have much higher cost associated with treatment. In any 60 case, the label recommendations of the selected algal control chemical must be closely followed. 40 Summary

Cells mL-1 x 1000 While the P. parvum bloom is 20 still ongoing in Lake Las Vegas, the preliminary lessons learned from this event are: P. parvum is unpredictable and 0 very quickly attained high densities with devastating effects on the “normal” biota; Dec 09 Jan 10 Feb 10 Mar 10 Apr 10 May 10 the literature is inconsistent and varies Figure 4. Prymnesium parvum abundance during the 2009-2010 bloom. by geography; limited and cost effective control options are available on large lakes and reservoirs; and P. parvum is a The common carp (Cyprinus carpio) options have been found effective in strong competitor and will likely have was by far the dominant species affected reducing P. parvum including copper long-term impacts to lake ecology. by the presence of P. parvum making compounds (Rogers et. al. 2010). The Preparation of full response plans may be up over 80 percent of the collected dead concept of whole lake treatment can unnecessary for each potential invasive fish (Figure 5). In addition, largemouth be daunting for many lake managers. species, but lake managers should prepare bass (Micropterus salmoides), channel Geographic influences and economic preliminary plans that address actions catfish (Ictalurus punctatus), and impacts play a large role in determining if, for example, chemical treatment is bluegills (Lepomis macrochirus) also the best action as it relates to control of identified as a possible control measure. were affected; at 11 percent, 5 percent, P. parvum. Regionally, the definition of What is the lead time to acquire necessary and 4 percent of the total, respectively. what constitutes a lake versus a pond can permits, purchase chemicals and secure a In this case, the influence of the common vary, but in general the concept of whole contract with certified aquatic herbicide carp’s feeding habit within the shallow littoral reaches of the reservoir possibly impacted this species more readily than other pelagic feeding game fish such as the largemouth bass since the life cycle of P. parvum includes a non-flagellated cyst form that may be present at high concentrations on the lake sediments. In most previously reported fish kills from P. parvum toxicity, game fish were the most common group. In contrast, rough fish were the primary fish lost in Lake Las Vegas.

Management of the Problem – Early Detection In 2009, the American Water Resource Association sponsored a symposium that focused on the current research knowledge base on P. parvum and management strategies, and a number of the important papers were published (Barkoh and Fries 2010). Early detection is key to determining if a treatment method is suitable for a specific Figure 5. Source water inlet structure in background with specimen of dead common carp in lake or pond. A number of treatment foreground.

30 Summer 2010 / LAKELINE applicator? Often state and municipal Steve Weber, Ph.D., agencies must deal with a lengthy is an environmental process to obtain these services, while consultant with RBF the problem species, requiring no permit, Consulting in Las rapidly overruns your lake. Vegas, Nevada. Dr. Weber has spent the References past 15 years working Barkoh, A. and L.T. Fries. 2010. Aspects on lake management- of the Origins, Ecology, and Control related issues in the of Golden Alga Prymnesium parvum: southwestern United States and continues Introduction to the Featured Collection. his research in limnology as a graduate J. Am. Water Resour. Assn. (JAWRA), faculty member at the University of Nevada 46(1):1-5. – Las Vegas, College of Community Health Rodgers Jr., J.H., B.M. Johnson, and Sciences. W.M. Bishop. 2010. Comparison of Three Algaecides for Controlling the Jeff Janik, Ph.D., Density of Prymnesium parvum. J. is a limnologist and Am. Water Resour. Assn. (JAWRA), consulting phycologist 46(1):153-160. with more than 30 years Southard, G., M., L.T. Fries, and A. experience. He was Barkoh. 2010. Prymnesium parvum: first exposed to desert The Texas Experience. J. Am. Water lakes during graduate Resour. Assn. (JAWRA), 46(1):14-23. studies on phytoplankton Weber, S. 2006. Influencing factors of four Colorado River on plankton population in a desert reservoirs. Jeff is with a state water agency man-made lake. Ph.D. dissertation. and focuses on water quality, nuisance University of Nevada, Las Vegas. 101 algae. and aquatic invasive species. x pp.

Summer 2010 / LAKELINE 31 New Approaches

Microbial Food Webs & Lake Management

Karl Havens and John Beaver

cientists and managers organism’s position in the food web. X magnification under a microscope) dealing with the open water Organisms occurring at lower trophic are prokaryotic cells that represent one (pelagic) region of lakes and levels (e.g., bacteria and flagellates) of the first and simplest forms of life Sreservoirs often focus on two are near the “bottom” of the food web, on the earth. Most are heterotrophic, components when considering water where energy and nutrients first enter meaning that they require organic quality or fisheries – the suspended the ecosystem. Organisms occurring at sources of carbon, however, some can algae (phytoplankton) and the suspended higher trophic levels (e.g., zooplankton synthesize carbon by photosynthesis or animals (zooplankton). This is for good and fish) are closer to the top of the food chemosynthesis. The blue-green algae reason. Phytoplankton is the component web, i.e., near the biological destination of (cyanobacteria) actually are bacteria, but responsible for noxious algal blooms and the energy and nutrients. We also use the for the purpose of this discussion, are it often is the target of nutrient reduction more familiar term trophic state, however not considered part of the MFW because strategies or other in-lake management only in the context of degree of nutrient they function more like phytoplankton solutions such as the application of enrichment. in the grazing food chain. Flagellates algaecide. Zooplankton is the component (Figure 1c), larger in size (typically 5 that provides the food resource for Who Discovered the to 10 µm) than bacteria but still very most larval fish and for adults of many Microbial Food Web? small compared to zooplankton, are pelagic species. Lake management that Although the concept of the MFW eukaryotes that similarly include species explicitly considers the pelagic food web may be new to lake managers, its that are heterotrophs – however, some uses approaches generally referred to potentially important role in the plankton are “myxotrophs,” meaning that they can as biomanipulation – where the goal is was recognized as early as the 1940s, carry out photosynthesis and make use of to reduce the biomass of phytoplankton when Lindeman (1942) hypothesized organic sources of carbon. by creating a situation that favors the that bacteria transfer energy to higher Flagellates are named for their dominance of large efficient zooplankton trophic levels in the pelagic zone of organelle of locomotion – the flagellum – such as Daphnia that can graze the lakes and ponds. A Polish ecologist, which may occur individually, as a pair, noxious algae. Z.M. Gliwicz, further elaborated on or in some atypical cases as three units. That these food web manipulations pathways of carbon and energy flow, The flagellum is a complex structure often are not successful (DeMelo et al. postulating that the link between bacteria largely comprised of tubes of protein that 1992), is due in part to additional food and zooplankton becomes predominant, is able to synchronously beat in order to web complexity beyond just algae, vs. algae to zooplankton, in lakes as move the cell through the water. Ciliates zooplankton and fish. In particular, a large they become more heavily enriched with (Figure 1d-f), the largest members of portion of the biomass, nutrient cycling, nutrients (Gliwicz 1969). The full scope the MFW (typically 20 to 50 µm), also and energy transfer in the pelagic food of the MFW, as we know it today, was are eukaryotic, and for the most part are web involves plankton components in a described by a marine scientist (Pomeroy heterotrophs. Their name comes from different pathway than the aforementioned 1974). In the late 1980s, the MFW was the fact that the cell surface is covered grazing food chain, including bacteria and widely studied in lakes and linkages made with fine cilia (each structurally similar a variety of different protozoa. with fisheries management, food web to a flagellum) that beat in synchrony to The aim of this paper is to describe efficiency, and water quality. propel the animal through the water and/ this microbial food web (MFW), identify or to generate feeding currents to capture its major components and their role in Who are the Major Players in the smaller food particles. the lake ecosystem, and discuss how Microbial Food Web? knowledge about the MFW can be helpful The MFW is comprised of three How Do They Interact as a Web? in guiding lake management. major components – bacteria, flagellates, The components of the MFW are and ciliates. Bacteria (Figure 1a-b), interconnected as part of a complex Trophic Levels and Trophic States ranging in size from about 0.5 to 2 µm (a network (Figure 2), in which organic In this paper the term trophic level µm is one millionth of a meter and cells carbon and energy are captured and is used in a context that considers an of this size are visible only at about 1,000 transferred to higher trophic levels

32 Summer 2010 / LAKELINE very fine particles (e.g., rotifers and a b certain cladocerans including Daphnia), or they can be grazed by flagellates and/ or ciliates in the MFW. Flagellates in turn are a food source for ciliates, rotifers, and many of the larger zooplankton. Ciliates are consumed by larger zooplankton, such as calanoid copepods, that can graze large food particles. Ultimately, the MFW transfers carbon and energy from the base of the food web (bacteria) to the top (zooplankton and fish). Early in the investigation of the marine MFW a controversy developed as to whether it functioned as a “link or sink” for carbon – the rationale for c d the sink argument being that much of the recaptured carbon is lost through respiration in the many steps in the longer chains (Ducklow et al. 1986). However, it was soon identified that the grazing food chain has a similarly low efficiency (Sherr et al. 1987). Thus, a reasonable way to look at the MFW is that like the grazing food chain, it is inefficient, however, it serves an important function of recapturing what otherwise would be lost carbon and energy. A considerable amount of the nutrient recycling that occurs in the pelagic zone also happens within the MFW, as phosphorus and nitrogen e f excreted by algae and zooplankton are picked up by bacteria and transferred upward in this web.

Does the Importance of the MFW Change with Lake Trophic State? In general, the importance of the MFW, whether measured as the percent of plankton biomass associated with bacteria, flagellates, and ciliates, or the percent of carbon and energy flow, has a unimodal relationship with lake trophic state – with greatest importance in ultra-oligotrophic lakes and hypereutrophic lakes, and Figure 1. Photomicrographs of representative components of the microbial food web of a lake or lowest importance in mesotrophic reservoir: (a-b) rod-shaped bacteria from Lake Erie photographed at 2000X, (c) flagellate from lakes (Stockner et al. 1989; Weisse and Lake Erie photographed at 2000X, (d) the ciliate Cyclidium sp. from Lake Erie photographed at Stockner 1992). There are, however, 2000X, (e) the ciliate Strombidium sp. from Lake Powell photographed at 630X, (f) the ciliate exceptions. Lakes in the mesotrophic Codonella cratera from Lake Okeechobee photographed at 400X. Scale bar is 10 µm. Photographed by Kyle Scotese, Teodoro Rosati, Jeff Johansen, and John Beaver. range that receive water with a high organic (humic) content will tend to support high rates of bacterial productivity (zooplankton and fish) in the lake released into the lake water. Bacteria and may have a food web that is ecosystem. When phytoplankton carry can incorporate some of this carbon into predominantly microbial (Tranvik 1992). out photosynthesis, they fix dissolved their own biomass, thereby recapturing Ultra-oligotrophic lakes, which largely

CO2 from the water into organic carbon carbon into the food web that otherwise have been investigated in Boreal regions, (glucose and subsequently other would have been lost. Subsequently, typically have much of their primary molecules), and during their metabolism the bacteria may be directly grazed by productivity associated with bacteria-sized and death, much of this fixed carbon is zooplankton that has the ability to filter phytoplankton called pico-plankton and

Summer 2010 / LAKELINE 33 How is this Information Important for Lake Management? The importance of plankton food web structure to fisheries productivity was identified in the late 1980s and Planktivores subsequently that information was widely applied in fisheries management. This work predominantly occurred in Canada, where John Stockner and his colleagues (Stockner and Shortreed 1989) documented that ultra-oligotrophic lakes in British Columbia, with MFW MaMacro-Zooplanktoncro-Zooc kton dominance and associated long food chains, had low efficiency in energy transfer (as noted above, because of many steps in the chains), and supported low fish productivity compared with oligotrophic lakes were the grazing food chain was predominant and fish MiMicro-Zooplanktoncro-Zooc tton productivity was higher. This information was part of the scientific foundation (the other part being a net loss of nutrients due to over-fishing that reduced return of fish to spawning grounds) for large-scale Protozoa fertilization of ultra-oligotrophic lakes, aimed at increasing algal productivity and enhancing the relative biomass of larger algae that could be directly grazed by zooplankton. From the standpoint of Bacteria Phytoplankton increased fisheries productivity and the associated socio-economic benefits this Figure 2. Food web diagram showing trophic links between the various components of the program was a great success (Stockner traditional grazing food chain (green arrows) and the microbial food web (brown arrows), and and MacIsaac 1998). subsequent links to fish. Carbon can enter this food web in two ways – by photosynthesis carried Lake managers more often are out by phytoplankton and certain flagellates, and by uptake of dissolved organic carbon by concerned with an excess of nutrients bacteria. rather than a lack thereof, and are engaged in projects to reduce nutrient inputs their dominant crustacean zooplankton there is a tendency for fish densities in order to reduce algal blooms, and/ is copepods that cannot graze such small and the associated predation pressure or conduct in-lake measures to enhance food particles. In those lakes the MFW on zooplankton to increase as species water quality and fisheries quality. plays a critical role where flagellates and like threadfin and gizzard shad become Because of the inefficient plankton food ciliates “package” the energy of the pico- increasingly dominant. This reduces the web and loss of summer refuges from plankton into particles large enough to be biomass of large effective zooplankton warm surface waters, hyper-eutrophic available to the copepods. In mesotrophic grazers such as Daphnia, leaving a lakes often lose their piscivorous fish lakes, a typical situation is dominance community dominated by smaller taxa (e.g., pike), which in turn releases smaller of the phytoplankton by moderate sized including rotifers, small cladocerans omnivorous fish from predation leading to diatoms, greens and cryptophytes, (e.g., Bosmina, Chydorus), and copepods greater grazing pressure on zooplankton and cladocerans such as Daphnia that that have escape maneuvers. At the same (Persson et al. 1988). The coincidence of can directly graze them. Under these time, the phytoplankton community shifts high fish predation and large blue-green circumstances, the MFW is present but toward increasing dominance by large algae results in small grazers that cannot plays a lesser role in carbon and energy filamentous and colonial blue-greens that eat the algae and therefore must rely on transfer than the grazing food chain. As are too large for the small zooplankton to the inefficient MFW. One strategy that lakes undergo eutrophication and proceed directly consume. This situation sets up may be helpful to make such foods more along the gradient from mesotrophic to the MFW as the main route for carbon efficient, under certain circumstances and eutrophic to hypereutrophic, two things and energy flow, as bacteria sequester in combination with nutrient reduction, is occur, leading to a plankton food web in carbon excreted by the algae and transfer biomanipulation – for example, stocking which the MFW is predominant. First, it upward to the zooplankton via flagellate lakes with piscivores and/or removing and ciliate grazers.

34 Summer 2010 / LAKELINE plantivores and omnivores to reduce and transfer some of it upwards to fish Sherr, E.B., B.F. Sherr and L.J. Albright. grazing pressure on zooplankton and via protozoa and small zooplankton. An 1987. Bacteria: Link or sink? Science allow large species such as Daphnia to understanding of this food web and how 235:88. become abundant (Figure 3). it can be manipulated has been used to Stockner, J.G. and K.S. Shortreed. When biomanipulation is successful successfully address low productivity 1989. Algal picoplankton production (and admittedly it does not always work), of fisheries in ultra-oligotrophic lakes and contribution to food webs in a part of that success is associated with and can potentially help lake managers oligotrophic British Columbia lakes. an increase in the relative importance achieve a successful enhancement of Hydrobiologia, 175:151-166. of the grazing food chain vs. the MFW. fisheries and water quality in eutrophic Stockner, J.G. and E.A. MacIsaac. 1998. This reflects the fact that Daphnia can lakes where biomanipulation methods are British Columbia Lake Enrichment graze a wide range of plankton particles, under consideration. Programme: Two decades of habitat from the smallest bacteria up to relatively enrichment for Sockeye Salmon. large ciliates and phytoplankton. This References Regulated Rivers: Research and “short-circuits” the MFW and results in a Crisman, T.L. and J.R. Beaver. Management, 12:547-561. much more efficient food web in regard 1990. Applicability of planktonic Tranvik, L.J. 1992. Allochthonous to supporting continued productivity of biomanipulation for managing dissolved organic matter as an energy fish. The trick, of course, is maintaining eutrophication in the subtropics. source for pelagic bacteria and the enhanced piscivores/planktivore ratio, Hydrobiologia, 200:177-181. the concept of the microbial loop. which might be an ongoing process in DeMelo, R., R. France and D.J. McQueen. Hydrobiologia, 229:107-114. temperate lakes if continued high nutrient 1992. Biomanipulation: Hit or myth? Weisse, T. and J.G. Stockner. 1992. inputs and algal blooms lead to anoxic or Limnology and Oceanography, 37:192- Eutrophication: The role of microbial hypoxia hypolimnetic waters and lack of 207. food webs. Memoirs Institut Italiano a summer refuge from high epilimnetic Ducklow, H.W., D.A. Purdie, P.J.L. Idrobiologia, 52:133-150. water temperatures. It is not an effective Williams and J.M. Davies. 1986. process in the subtropics where large Bacterioplankton: A sink for carbon in Daphnia do not occur, cyanobacteria are a coastal marine plankton community. Karl Havens is director abundant, and the MFW is quite important Science, 232:865-867. of the Florida Sea Grant (Crisman and Beaver 1990). Lindeman, R.L. 1942. The trophic- College Program at the dynamic aspect of ecology. Ecology, University of Florida, Summary 23:399-418. Gainesville, FL (e-mail: In addition to the traditionally Persson, L., G. Andersson, S.F. Hamrin khavens@ufl.edu). He recognized algal-zooplankton “grazing and L. Johansson. 1988. Predator has conducted research food chain,” the plankton of lakes and regulation and primary production dealing with plankton reservoirs includes a more complex along the productivity gradient of food webs since the early microbial food web where bacteria take up temperate lake ecosystems. Pp. 45- 1980s, and has published over 140 journal dissolved organic carbon from the water 65. In: S.R. Carpenter (Ed.), Complex articles, book chapters and review papers. (carbon released from algae excretion or Interactions in Lake Communities, He received his Ph.D. and MS degrees from carbon entering from outside the lake) Springer-Verlag, NY. West Virginia University and his BA degree from the State University of NY at Buffalo.

a Bosmina b Daphnia John Beaver is President of BSA Environmental Services in Beachwood, Ohio Anabaena bacteria flagellates bacteria (e-mail: j.beaver@bsaenv. com). He is an aquatic ecologist specializing in North American lake water quality. Dr. CO DOC CO DOC 2 2 Beaver has authored approximately 40 referred journal articles related to aquatic microbiology and limnology in the scientific Figure 3. Two simple food web diagrams, showing cases of (a) low efficiency of carbon and literature. He received a Ph.D. and MS from energy transfer when small zooplankton co-occur with large inedible algae; and (b) high the University of Florida in Environmental efficiency of carbon and energy transfer when large Daphnia co-occur with edible algae. From a Engineering Sciences and a BS from fisheries or water quality standpoint, condition (b) is usually desired. CO2 represents the inorganic carbon taken up by algal photosynthesis and DOC is dissolved organic carbon excreted by algae. Jacksonville University in Biology. x This is a highly simplified diagram and neither respiratory carbon losses nor release of DOC from zooplankton during feeding and excretion are shown.

Summer 2010 / LAKELINE 35 New Approaches

A Decade of Starry Stonewort in Michigan

G. Douglas Pullman and Gary Crawford

Observations and Operational Management Considerations – mats and may contribute more odors to 1999 to 2009 samples that contain both plants. Introduction to the sediments in the late fall and Starry Stonewort Terminology tarry stonewort (Nitellopsis early spring (Figure 2). It also produces A new terminology has been obtusa [Desv.] J.Grove) is conspicuous, orange-colored oocytes developed and used by investigators considered an exotic charoid that are easily detected by the naked eye and herbicide applicators in Michigan Sspecies in North America. It (Figure 3). Starry stonewort is a light to describe the growth and development has reportedly been present in Lake St. green color when it is actively growing, of starry stonewort communities. These Clair since 1986 (Schloesser 1986). In compared to other charoid species in terms have been useful to facilitate better stark contrast to other invasive species Michigan. It is like Nitella where the communications between observers such as the zebra mussel, starry stonewort stem-like thallus is comprised of a single and aquatic plant control practitioners has apparently taken nearly 30 years cell. If the thallus is broken, the cellular and may be found useful by others. to become conspicuous in Michigan contents can be easily expressed from the “Pillowed” is a term used to describe inland lakes. Anecdotal observations cell and leave a translucent “tube-like” the stage where starry stonewort covers suggest that it may have been present cell wall. Compared to other charoid algae nearly all of the sediments in an area and in several southeastern Michigan lakes in Michigan, the branching pattern of forms irregular, undulating “pillows” as early as 1999, but was thought to be starry stonewort is more irregular giving of biomass (Figure 4). This stage forms a “super weedy chara.” Reflection also the plant a characteristic “disheveled” and persists into ultimate stage of starry suggests that it may have been present look. stonewort invasion, which is referred to as in some lakes where fluridone had been Unlike other Michigan charoid algae, “packing.” used to manage milfoil populations and starry stonewort can grow to remarkable The term “packing” refers to a starry where successful milfoil control resulted heights and depths. This characteristic stonewort population that has filled all in a “chara” bloom. Unfortunately, can also aid in identification. It has been available habitats and has moved upslope samples were not preserved from any of observed growing 2 meters (7’) tall at 9 and downslope into areas that do not these lakes. Starry stonewort was first m (29’) water depth in Williams Lake, appear to be ideal but still adequate for positively identified on February 6, 2006 Oakland County. Starry stonewort forms its growth. The term “cheesy” is used to by G. Douglas Pullman in Lobdell Lake, dense mats of vegetation that completely describe starry stonewort when it appears Genesee County, Michigan. Since that cover the lake bottom. When it becomes to be dormant or is in decline. Holes time it has been found in Michigan lakes dense and overcomes most of the other open in the starry stonewort mats that in the Lower Peninsula, ranging from vegetation in an area, it is said to “pillow” resemble the hole pattern in Swiss cheese. Mason County to Wayne County. It is or form irregularly spaced “pillows” of “Hair cut treatments” is a term used to probably present in nearly every county in dense vegetation of various heights rather refer to algaecide treatments that reduce the Michigan Lower Peninsula, although than a mat of uniform height. When the height of the starry stonewort mats this is still conjecture. The invasion and the growth slows or the plants decline without eliminating all starry stonewort growth of stonewort has been observed in (usually in the summer) circular openings biomass in a treatment area. The reasons the Michigan lakes listed in Table 1. may appear in the dense pillowed mats that this is used are described below. imparting a “Swiss cheese” pattern in the Identification pillowed mats. Biology The starry rhizoids are definitive for Most charoid algae have a musky Starry stonewort is thought to identification of starry stonewort (Figure or garlic odor. This odor is not nearly as be native to Europe and is classified 1). They have been observed on all parts pronounced in starry stonewort. However, as endangered in the U.K. The U.K. of the plant at all times of the year in caution must be taken here because some Biodiversity Action Plan (available Michigan Lakes, but are particularly chara species appear to be capable of co- at www.ukbap.org.uk/UKPlans. common on the plant parts that are closest mingling in the dense starry stonewort aspx?ID=474) describes starry stonewort

36 Summer 2010 / LAKELINE Table 1. A List of Michigan Lakes Where the Authors Have Observed Starry Stonewort.

Occurrence as Observed in the Maximum Number of BOS* Lake Name County Date of First Observation 2006 2007 2008 2009 Lobdell Lake Genesee and Livingston February, 2006 88% 97% 92% Indianwood Oakland July, 2006 93% 100% 100% Sears Oakland July, 2006 n/a n/a n/a n/a Softwater Oakland July, 2006 n/a n/a n/a n/a Lower Straits Oakland June, 2006 n/d n/d 11% Pleiness Mason June, 2006 n/a n/a n/a n/a Sears Oakland June, 2006 n/a n/a n/a n/a Whitmore Livingston and Washtenaw June, 2006 7% 40% 26% 18% Williams Oakland June, 2006 70% 68% 78% Cedar Alcona and Oscoda June, 2007 n/d 65% 33% 0% Iron Washtenaw June, 2007 n/a n/a n/a n/a Joslin Washtenaw June, 2007 n/a n/a 27% Kent Oakland June, 2007 n/d 4% 35% 50% North Washtenaw June, 2007 n/a n/a n/a n/a Ogemaw Ogemaw June, 2007 n/d 74% 10% 3% Sanford Midland June, 2007 n/a n/a 11% 0% Waumegah Oakland June, 2007 n/a n/a n/a n/a Millecoquin Mackinac August, 2007 n/a n/a n/a n/a Bass Mason June, 2008 n/d n/d 6% 0% Stony Macomb June, 2008 n/d n/d 23% 5% Tipsico Oakland June, 2008 n/d n/d 53% Wamplers Lenawee June, 2008 n/a n/a n/a n/a Big Oakland May, 2006 n/d n/d 47% Tamarack Montcalm October, 2006 n/a 65% 72% 1% Townline Montcalm October, 2007 n/d n/d 87% White Oakland September, 2007 n/a 75% 67%

*Maximum number of biological observation sites (BOS) is represented as a percentage of the total number of biological observations sites at each lake where starry stonewort was observed.

Figure 1. Starry stonewort – Nitellopsis Obtusa. Figure 2. Star-shaped rhizoids are definitive for identification.

Summer 2010 / LAKELINE 37 Figure 3. Orange-colored oocytes are female gametocytes Figure 4. Dense pillow of starry stonewort. from which an egg develops. as a plant that prefers deeper, less been observed in Indianwood (2007 and associated with the early invasion of alien turbulent water, and as becoming 2008), Lower Straits (2008), Sears (2008), aquatic plants; however, starry stonewort increasingly rare. The starry stonewort and Williams (2006, 2007, and 2008) has quickly become established in many observed in Michigan lakes also appears lakes during the hot summer months. lakes that have no public access. The role to thrive in deeper water, but will also It is common to observe the collapse of waterfowl in the dissemination of starry thrive in shallow water where it will grow or regression of opportunistic, non- stonewort could be very significant. at the water surface. It does not appear to endemic aquatic macrophyte species in Starry stonewort is also easily grow well in boat lanes and high-energy Michigan Lakes. Collapse and regression fragmented and these fragments could shorelines. It will; however, grow in also appear to be part of the production seemingly act as disseminules that could boat lanes when it has colonized or filled patterns observed in starry stonewort. be important in the spread of the plant virtually all of the habitable area of the For unknown reasons, starry stonewort within a lake and from lake to lake. Boat lake. It grows well in a wide range of was observed growing aggressively in traffic can cause significant fragmentation Michigan Lake types including clearwater many Michigan inland lakes in the early of starry stonewort that can float on and dark water systems. It will colonize summer of 2009 (e.g., Indianwood, parts the water surface and create nuisance highly organic, unconsolidated sediments of Lobdell Lake); however, it appeared conditions on leeward shorelines. This and sands and gravel. It seemingly shows to be dormant in others (e.g., Whitmore). type of fragmentation has been implicated no preference for shade or full sun. The Conditions were cool all summer in 2009 in the dissemination of other alien species lakes from which these observations were and rapid growth was anticipated; but, in Michigan such as the invasive milfoils made are not routinely monitored for highly invasive growth did not occur (Eurasian and hybrids). water hardness, but are typical hard-water in many lakes until October. Starry Michigan lakes where calcium carbonate stonewort appears to be so sensitive to Plant Community Interactions alkalinity ranges from 110 to 190 mg/L as aquatic pesticides that some of the lower Starry stonewort invaded the

CaCO3. Total phosphorus concentrations production levels observed in 2009 may nearshore areas of Michigan lakes at in infested lakes run from below 10 ppb to have related to plant control efforts that water depths ranging from approximately 80 ppb (Tipsico Lake, Oakland County). were specifically focused on herbicide 0.5m to 1.5m (2’ to 4’) deep and then The U.K. Biodiversity Action tolerant nuisance plant populations spread downslope and upslope from that Plan (www.ukbap.org.uk/UKPlans. where potent mixtures of herbicides were point in the lake. This seems to be the aspx?ID=474) describes starry stonewort necessary to achieve adequate control. typical invasion pattern, but it may have as an annual plant that may overwinter Starry stonewort spreads rapidly from colonized deeper areas of lakes and not in mild winters. Contrastingly, the starry lake to lake. It produces oocytes, as do been observed. It is the most aggressive stonewort in Michigan appears to thrive other charoid algae, and these structures aquatic plant ever observed in Michigan in the cooler waters of fall, winter, and are transported easily on bird feathers or and is able to out-compete all other spring, and becomes dormant or less the fur of aquatic animals. They could Michigan plant species, including all active during the hottest part of the also be easily transported in aquatic plant invasive species and current alien species summer. However, extremely active, debris caught on boat trailers. Often, such as Eurasian watermilfoil, fanwort, nuisance-level production and growth has the presence of public launch sites is and curly leaf pondweed. A precipitous

38 Summer 2010 / LAKELINE decline in biodiversity index values was and indirect impact on water clarity. Though concern for gamefish has expected in lakes where presence and The water clarity in lakes infested with been voiced by riparians on infested lakes absence data, density, and distribution starry stonewort appears to increase with there is also concern for biodiversity of patterns were subjected to the LakeScan™ increasing domination of the benthic lake fauna such as native fish species lake analysis tools developed by the community. Indirectly, starry stonewort including logperch, darters and various authors, but this has not always been can be a favored substrate for zebra minnow species, native clams, and observed. It is not uncommon to see a mussels, and the filtering impact of zebra invertebrates whose intimate association single errant plant of competing species, mussels and their affect on water clarity with the lake bottom is absolutely growing in the depressions between the is well known. It is also possible that necessary for survival. pillowed patches of starry stonewort the upper parts of the dense plant mats In 2009, a LakeScan™ critical biomass. It is obvious in all of the infested compete effectively with phytoplankton fishery habitat survey was conducted lakes that the biomass of competing for nutrient resources. And, there is in Whitmore Lake, Washtenaw County, species has declined significantly where speculation that charoid algae are capable Michigan. During the survey, redear starry stonewort has spread and come of producing allelopathic compounds sunfish (Lepomis microlophus) were to dominate the lake flora. This would (Mulderij et al. 2007). observed nesting on a newly developing certainly have been reflected in biomass mat of starry stonewort that had covered estimates, however, these values were not Critical Fish Habitat Impacts a traditional nesting site. This species is compiled for any of the lakes upon which Starry stonewort directly impacts fish not native to Michigan but has become these observations have been made. spawning habitat by the formation of a naturalized through public and private It appears that starry stonewort can thick mat that serves as a physical barrier stocking efforts. A closer inspection act like a commercial benthic barrier effectively impeding access to substrates revealed that the nests were absent of that contributes to the accumulation for nest creation resulting in (1) reduction sand and gravel and starry stonewort had of phytotoxins, such as volatile fatty in nesting area and density of nests and been pressed down within the spawning acids (VFAs), and render the sediments (2) complete elimination of spawning depressions. The sunfish demonstrated the inhospitable for plant growth until the activity in the area of infestation. In lakes territoriality and nest guarding behavior conditions change, redox potentials supporting a mature and/or expanding associated with active reproduction. increase, and VFAs are oxidized or diffuse infestation of starry stonewort, spawning Redear sunfish were observed utilizing from the sediments. There would be fish must compete for remaining spawning both sand gravel habitats in other certain obvious benefits to the rootless habitat in areas that are suboptimal for traditional spawning sites within the lake. starry stonewort when redox potentials are spawning. Rock bass, smallmouth bass, largemouth suppressed and nutrients are released from An attempt was made to clear known bass, bluegill, and pumpkinseed sunfish the sediments. traditional nesting sites with chemical nests were observed during the survey Interestingly, certain plant species controls during the spawning season in but these species completely avoided seem to thrive in the presence of Big Lake, Oakland County, Michigan in starry stonewort, preferring sand gravel starry stonewort. The apparent benthic 2008. The chosen area was successfully complexes as spawning substrate. It barrier impacts on sediment chemistry cleared and spawning activities began; appears that redear sunfish will not be may be the reason that the rootless however, starry stonewort re-colonization greatly impacted in by starry stonewort bladderworts and coontail can thrive in of the cleared area occurred so rapidly that during early stages of infestation. starry stonewort infested lakes. These a successful spawn was not completed. Critical nursery habitat consists of plants would not have to cope with low Michigan riparians inadvertently areas that provide optimum conditions for redox concentrations and associated maintained traditional nesting sites, free growth and safety for fry and juveniles bio-geochemical factors that would of starry stonewort, in both Williams Lake of a myriad of fish species. These areas sour the rhizosphere; but they may still and Lake Waumegah, Oakland County, exhibit a high degree of vertical structural benefit from the release of nutrients from using labor intensive mechanical methods complexity in the form of vegetation the sediments. Common bladderwort or weed rollers. Although the removal and/or drowned timber that provide (Utricularia vulgaris), reached near of starry stonewort was done to support niche habitat for feeding and refuge nuisance levels in Indianwood Lake swimming and boating activities, a high from larger predators. In temperate in 2008 and 2009 in the presence of degree of utilization by spawning sunfish lakes shallow areas provide warmer starry stonewort. Water lilies seem to be was observed. Spawning was minimal or temperatures for increased metabolic rates able to compete effectively or are not absent in areas immediately adjacent to and rapid growth. Starry stonewort’s mat apparently diminished by starry stonewort the clearings. Both bass and sunfish will forming growth habit reduces structural until the starry stonewort occupies the spawn readily in areas containing dense complexity by physically and possibly water surface The visual impact of growths of native chara. By comparison, chemically preventing the growth of starry stonewort and the influence on areas in close proximity but dominated aquatic macrophytes. Observations in the submersed flora of Michigan lakes by starry stonewort of relatively equal nursery habitat areas over time show cannot be understated. But these impacts density did not exhibit spawning activity. a gradual decrease in stem density and are not confined to the macroflora. Starry We are unsure why this occurs. number of plants as starry stonewort stonewort also appears to have a direct prohibits growth of pondweeds, milfoils,

Summer 2010 / LAKELINE 39 and water lilies. Elimination and reduction Clemson University as of this writing, and and will eliminate nuisance milfoil growth of niche habitat may result in increased operational results are being analyzed to from the deeper parts of some lakes. And, mortality of young-of-the-year and develop more effective control strategies. if the water is clear, starry stonewort will juvenile fish species of both native and Field data collected in 2009 also suggest not grow as tall in the water column. non-native species. Rare and imperiled that starry stonewort may be susceptible Riparian property owners, recreational fish species such as the pugnose shiner to a broader range of aquatic herbicides water users, and some lake managers have (Notropis anogenus) and starhead than was considered in previous years. been very pleased with this outcome. If topminnow (Fundulus dispar) are at There was a significant decline in the starry stonewort grows taller, the height particular risk due to the fact that robust percent occurrence of starry stonewort as of the starry stonewort can be reduced stands of aquatic vegetation are critical to observed in biological observation sites with low level algaecide treatments. This their survival. in any lakes in 2009 as an apparent result is referred to as a “hair cut treatment” Loss of woody habitat complexity of nuisance plant control efforts that were and is used to suppress plants like milfoil beneath mats of starry stonewort conceals focused on herbicide tolerant aquatic through competition and still keep fish structure from anglers and results angiosperms (in Bass, Cedar, Lobdell, boat lanes open. The wisdom of such a in a change in distribution and decrease Sanford, White, and Whitmore lakes). treatment strategy may be debatable, but in condition of largemouth bass as a These management efforts included the utility of the approach has been very result of a change in predatory strategy mixtures of herbicides that included a effective. from the more efficient sit and ambush product known as Cutrine Ultra (Applied The timing of starry stonewort strategy to the less efficient chase strategy Biochemists, Germantown, WI). Cutrine treatment is also worthy of consideration. within the pelagic zone (Sass et al. 2006). Ultra, combined with other herbicides, Early treatment may be necessary, to Critical woody habitat is often rare in appeared to be the factor that has resulted open spawning habitats. However, early developed lakes and primarily consists in the consistent suppression of starry treatment may open large areas of the lake of sunken snags or stumps. The rate of stonewort. bottom to colonization by early growing natural addition of new woody structure Mechanical harvesting was used season species such as milfoil, milfoil is also low because of fewer trees along for the control of starry stonewort in hybrids, curly leaf pondweed, fanwort, or the shoreline of a developed lake. Loss Indianwood Lake and has been used other highly undesirable invasive species of this critical habitat to starry stonewort for the control of other nuisance plant in Michigan. If treatment is delayed to encroachment represents a serious threat growth in some of the other lakes that late June, the adverse impacts on these to a valuable form habitat already in short are inhabited by starry stonewort. The early-growing invasive species may be supply. amount of biomass produced by starry exaggerated. Presumably, some of the stonewort in a relatively small area can more desirable pondweed species may Starry Stonewort Management very quickly fill a mechanical harvesting benefit from the suppression of these Starry stonewort appears to be highly machine to capacity and cause harvesting vascular invasive species and the creation sensitive to common copper and endothall operations to be very slow relative to the of habitat when the starry stonewort is based algaecides and appears to be even harvesting of other nuisance vascular removed late in June. This strategy is only more susceptible than are most common plant species. The “sponge”-like mats one of several that is being considered and Michigan charoid species. The application of starry stonewort are also prone to roll evaluated in Michigan. rates recommended for chara control on down the forward conveyor of some the U.S. EPA approved pesticide labels harvesting machines making it difficult Concerns and Questions appear to be sufficient to control low- to pick the cut plants off of the surface of Starry stonewort may be the greatest growing starry stonewort. Problems can the water. Starry stonewort appeared to challenge that has ever faced lake arise when starry stonewort mats become grow faster than any competing plants in management professionals and lake tall. The algaecide application rates the harvested areas of Indianwood Lake user groups in Michigan. The impact on that are normally used in chara control and this shifted the plant community to a Michigan fisheries could be profound. operations usually cause impacts on only mono-culture of starry stonewort in 2007. Although it is relatively easy to control, the upper surface of the starry stonewort The resulting outcome was inconsistent management strategies need to be fine mats. It appears that the active ingredients with the lake management goals for that tuned to be more effective and useful. are sequestered in the upper portions of lake and harvesting operations were There are many questions that need to be the starry stonewort mats and the lower suspended in 2008. answered or investigated to gain a better portions of the mats are not injured. Injury The ability to control only the understanding of the biology and threat can be caused at greater depths in the upper biomass of starry stonewort mats to Midwestern and North American lakes starry stonewort mat when chelated agents presents some interesting aquatic plant that is posed by the spread of the starry are used, the amine salt of endothall management opportunities. Many of the stonewort in Michigan. The following (Hydrothol 191, United Phosphorus, lakes where starry stonewort has been points are offered for discussion and to Inc., King of Prussia, PA) is added as an found have historically been challenged possibly guide researchers. adjuvant or other adjuvants are added to by the spread, proliferation, and 1. BASIC BIOLOGY: The biology of the algaecide mixture. Challenge testing domination of milfoil species and hybrids. starry stonewort is very different in is being performed in laboratory studies at Starry stonewort is a superior competitor Michigan. Curiously, it was known

40 Summer 2010 / LAKELINE to inhabit Lake St. Clair for nearly 30 6. SEDIMENT IMPACTS: Starry habitat by yellow perch in lakes? Do years before it became conspicuous in stonewort seems to have a dramatic redear sunfish nests yield the same inland lakes. It is currently spreading impact on sediment bio-geochemistry. number of swim up fry in starry rapidly throughout the lower peninsula The impact on redox potentials, stonewort and sand gravel complexes? of Michigan. Is this a novel genotype the availability of suitable electron How much critical spawning and or even a hybrid? acceptors for the terminal stages of nursery habitat is enough to support 2. EPIPHYTE AND AWFUCH sediment diagenesis (breakdown), viable fish populations in inland COMMUNITY INTERACTIONS: and the accumulation of phytotoxic lakes? Is angler dissatisfaction in There is evidence from the Great volatile fatty acids that certainly starry stonewort lakes linked to Lakes that cladophorales algae benefit accumulate below dense starry density, condition or distribution of from being in close proximity to the stonewort mats would be another area fish? pseudofeces of zebra mussels which of investigation to understand better 11. STARRY STONEWORT are able to supply necessary plant the recolonization of areas by rooted MANAGEMENT: Although there nutrients. The association of zebra vascular plants that previously were seem to be a myriad of ways to mussels and starry stonewort is also dominated by starry stonewort. control starry stonewort, better ways very strong and seems to suggest that 7. IMPACTS ON PRIMARY could be developed to control its these same benefits may be provided PRODUCTION: There is evidence growth with lower concentrations to starry stonewort, while starry that charoid algae can serve as a of active ingredients. The timing of stonewort provides zebra mussels with nutrient sink, by a wide variety control operations is likely to have a suitable attachment substrates. of mechanisms, and thereby significant impact on the subsequent 3. The awfuchs community that limit primary production though recolonization of areas where starry colonizes the surface of starry resource deprivation (Blindlow et stonewort was once the dominant stonewort has not been investigated. al. 2004). The production, presence, macrophyte due to the impact of dense This community could also be key to and function of starry stonewort starry stonewort mats on sediment the successful upward growth of starry allelopathic compounds would be biogeochemistry. Better estimates stonewort, as epiphytic cyanobacteria difficult to investigate, but needs to of the rate of starry stonewort are known to fix nitrogen on charoid be considered for a wide range of encroachment on areas that have been algae in rice paddies. Manipulation reasons. cleared for restoration of spawning of these communities may help to 8. The impact of starry stonewort habitats need to be made to calculate regulate upward growth of starry on the richness and diversity of how large an area must be managed to stonewort pillows and mats. phytoplankton communities may be protect these resources. 4. BASIC WATER QUALITY: profound. Blue-green algae blooms 12. STARRY STONEWORT Starry stonewort appears to have a have been observed in some lakes that PRODUCTION: The biology of profound impact on water clarity are dominated by starry stonewort starry stonewort has been confusing. in Michigan Lakes. The impact of (Williams Lake, Lobdell Lake, The populations in some lakes seem starry stonewort on the inorganic Indianwood Lake). The association to exhibit slow growth or may even and nutrient chemistry of lakes has of starry stonewort with zebra mussel decline in the hot summer months not been directly addressed. Starry may be significant. while continued growth has occurred stonewort phosphorus demand 9. IMPACTS ON SECONDARY in other lakes. The differences in the may limit essential and desirable PRODUCTION: It is reasonable to populations may be genetic or may be plankton community production expect a shift in zooplankton species determined by other factors. Does the in starry stonewort lakes (too little from those associated with pelagic appearance of open pockets (cheesy phosphorus). Allelopathy may habitats to species associated with effect) suggest that starry stonewort also play a role in the reduction of littoral habitats. And, the expected mats may collapse soon? When with phytoplankton production. impact on benthic invertebrates may the exponential growth phase of starry be profound. stonewort begin so that management 5. PLANT COMMUNITY DIVERSITY: efforts can be better timed? These Starry stonewort seems to extirpate 10. IMPACTS ON FISHERIES: Some of considerations and the differences most submersed plant species; the questions that we have considered observed in different lakes need to be however, long-term studies have are: Are temperate lakes that support investigated to improve management not provided any indication of what extensive and mature infestations of practices. aquatic plant communities may starry stonewort more vulnerable to become after years of cohabitation winter kill if large amounts of biomass Acknowledgements with starry stonewort. Some plants, are carried over into times of the year These observations were made such as bladderworts and coontail where there is ice cover? How do possible by the residents of the special appear to be benefited by starry increases in water clarity and possible assessment districts created in Michigan stonewort infestations. reductions in dissolved organic carbon to facilitate lake management, protection, effect the selection of spawning and improvements. Many lake leaders and

Summer 2010 / LAKELINE 41 interested individuals (too many to list) stonewort on lakes other than those listed G. Douglas Pullman, have provided observations and comments specifically in this manuscript. Ph.D., is president of that have had a profound impact on the Aquest Corp, which way observations have been collected References will celebrate 20 years and reported. The membership of the Blindow, I., A. Hargeby and G. of lake management Michigan Aquatic Managers Association Andersson. 2002. Seasonal changes of consulting in 2011. is also acknowledged for their formal and mechanisms maintaining clear water Operations are informal input to the discussions that led in a shallow lake with abundant Chara maintained in Michigan to the development of this manuscript. We vegetation. Aquatic Botany, 72(3-4): and Florida. Doug is also wish to acknowledge the input and 315-334. co-developer of the LakeScan™ lake statis discussions provided by Dr. Jerry Sanders Mulderij, G., E.H. Van Nes and E. Van analysis tools. He enjoys finding new aquatic and Dr. Ann Sturtevant, University of Donk. 2007. Macrophyte-phytoplankton plants and playing guitar. Michigan – Flint who have brought a interactions: The relative importance unique perspective to this manuscript. of allelopathy versus other factors. Gary Crawford is a senior scientist (aquatic We also wish to thank Gary Towns and Ecological Modeling, 204(1-2):85-92. biologist) with Superior Environmental Jim Francis of the Michigan Department Sass, G.G., J.F. Kitchell, S.R. Carpenter, and Aquatic Services LLC. He has over 15 of Natural Resources and Environment T.R. Hrabik, A.E. Marburg and M.G. years experience in aquatic ecosystems (MDNRE), Lake Erie Management Turner. 2006. Fish community and food of the Great Lakes region. Gary has been Unit, for their insight and contributions web responses to a whole-lake removal responsible for developing new mapping to discussions regarding potential of coarse woody habitat. Fisheries, 31: and monitoring techniques and associated impacts to fisheries and the development 321-330. metrics for critical spawning and nursery of management strategies. We also Schloesser, D.W., P. L. Hudson and S. habitat analysis within Michigan inland lake acknowledge input and comments from Jerrine Nichols. 1986. Distribution and ecosystems. x Eric Bacon, Lisa Huberty, Matt Preisser, habitat of Nitella obtusa (Characeae) and Brett Wisely, MDNRE Inland Lakes in the Laurentian Great Lakes. Unit, as they shared their observations in Hydrobiologia, 133:91-96. regard to the spread and impacts of starry

42 Summer 2010 / LAKELINE EPA CommentaryAmina Pollard

The National Lakes Assessment: The Results Are In

Introduction oxygen and algal density; biological Findings he U.S. Environmental Protection indicators such as phytoplankton and The NLA finds that 56 percent of the Agency (EPA) recently released zooplankton; recreational indicators nation’s lakes support healthy biological Tits most comprehensive study such as algal toxins and pathogens; communities when compared to least of the nation’s lakes to date (see and physical habitat indicators such as dis turbed (e.g., reference) sites. Twenty- www.epa.gov/lakessurvey). The study, lakeshore and shallow water habitat cover. one percent of lakes are in fair biological which finds that the health of lake shore NLA results are reported for the condition, and 22 percent are in poor habitats is strongly associated with the continental U.S. and for nine ecoregions condition (Figure 1). overall biological condition of lakes, based on landform and climate The study shows that poor habitat marks the first time EPA and its state characteristics. In addition, nine states condition along the lakeshore (found in and tribal partners used a nationally participating in the NLA assessed lake 36 percent of lakes) is the most significant consistent, statistically based approach to condition at the state-scale by sampling stressor in lakes. In fact, the study finds survey the ecological and water quality of additional random sites within their that poor biological health is three times U.S. lakes. boundaries. more likely in lakes with poor lakeshore The National Lakes Assessment (NLA) is the latest in a series of surveys of the nation’s aquatic resources being conducted by EPA and its state and tribal partners. The NLA provides unbiased estimates of the condition of natural and man-made freshwater lakes, ponds, and reservoirs greater than ten acres and at least one meter deep. Using a statistical survey design, EPA selected lakes at random to represent the condition of lakes across the 48 contiguous states. A total of 1,028 lakes were sampled for the NLA during summer 2007, representing the condition of about 50,000 lakes nationwide, not including the Great Lakes and Great Salt Lake. Field crews collected samples using the same methods at all lakes to ensure that results could be compared across the country. At each lake, crews collected samples (primarily water quality indicators) at a single station located at the deepest point in the lake and at ten stations around the lake perimeter (primarily physical habitat and biological indicators). Researchers analyzed 680,000 data points, including measures of water quality such as nutrients, dissolved Figure 1. Summary of biological conditions in the nation’s lakes

Summer 2010 / LAKELINE 43 habitat than in lakes with good habitat. based on chlorophyll-a concentrations. on the NLA Web site (www.epa.gov/ Removing natural shoreline vegetation The study found that 13 percent of lakessurvey) when they are completed. and constructing docks, marinas, homes, lakes are oligotrophic, 37 percent are and other structures along shorelines mesotrophic, 30 percent are eutrophic, Implications contribute to degraded lakeshore habitat. and 20 percent are hypereutrophic. The The NLA results allow EPA and High levels of the nutrients nitrogen results suggest that natural lakes tend its state and tribal partners to begin and phosphorus are found in 20 percent toward mesotrophic conditions and man- answering important national questions of lakes. Excess nutrients entering the made lakes toward eutrophic conditions. about the condition of the country’s lakes. lakes from a variety of point and nonpoint The NLA findings suggest that, for at The survey results establish a national sources contribute to algae blooms, weed least a subset of lakes, water quality has baseline status for future monitoring growth, reduced water clarity and other improved since the 1970s. The NLA re- efforts that can be used to track trends in lake problems. Poor biological health is sampled a subset of wastewater-impacted lake condition. Successive surveys will 2.5 times more likely in lakes with high lakes that had been studied 35 years ago help determine how lake condition is nutrient levels (Figure 2). under the National Eutrophication Survey changing over time. Planning is already The NLA included the first national- (NES); the comparison indicates that beginning for the NLA II; sampling will scale assessment of algal toxins in lakes. phosphorus levels dropped in nearly 50 take place in 2012. Researchers observed microcystin – a percent of the 800 NES lakes. Trophic In the meantime, in the face of toxin that can harm humans, pets, and status improved in about 25 percent incredible development pressures wildlife – in 30 percent of lakes, and of those lakes. These data suggest that around lakes, the NLA findings suggest at levels of concern in one percent the nation’s investments in wastewater that our lakes are vulnerable to human of lakes. Microcystin samples were treatment and other pollution control disturbance, especially along the lake- collected at mid-lake, in open water; activities are having an effect despite shore. Local, state, and national initiatives however, concentrations may be greater in increased population pressures. should center on protecting shoreline nearshore areas. Therefore, NLA results The NLA also collected samples habitats, in particular, maintaining natural may underestimate recreational exposure for several indicators of lake condition vegetative cover and wisely managing when accumulations or algae scums are that are still being analyzed: benthic lakeshore development. Furthermore, present. In planning for the next lake macroinvertebrates; Enterococci since the NLA identified nutrient pollution survey, consideration will be given to bacteria, which serve as an indicator as the second-leading lake stressor, lessons learned from the microsytin for the presence of more dangerous watershed stakeholders should continue sampling and analysis. pathogens; mercury in sediments; and to press for successful, innovative ways The overall trophic state of lakes in invasive aquatic species. The results of to control point and nonpoint sources the U.S. was characterized in the NLA these analyses will be made available of nutrient pollution throughout lake watersheds. To learn more about the NLA, download the archived version of “National Lakes Assessment: A Collaborative Survey of the Nation’s Lakes,” a two-hour Watershed Academy Webcast presented on Jan. 5, 2010. See www.epa.gov/watershedwebcasts. The NLA is available at www.epa. gov/lakessurvey. Data from the NLA are also available on this survey Web site. Hard copies of the NLA (publication number EPA 841-R-09-001) may be ordered from the National Service Center for Environmental Publications at 1-800- 490-9198. To learn more about EPA’s National Aquatic Resource Survey program, visit www.epa.gov/aquaticsurveys.

Amina Pollard is the EPA Team Lead for the National Lakes Assessment. x

Figure 2. Lake stressors and their effect on biological condition.

44 Summer 2010 / LAKELINE Affiliate News

California Lake Management natural wetland rehabilitation project in Club, Diamond Lake Conservation Club, Society (CALMS) the Tahoe Basin. and Yellow Creek Lake Conservation CALMS held its annual meeting The 2010 CALMS meeting (the Club, and a Saturday’ rain barrel workshop th October 15-16, 2009 at Kings Beach, CA, 25 annual) will be in Palm Springs as their favorite presentations. During the which is on the north shore of beautiful on October 7-8. Anyone interested is partnership presentation, the presenters Lake Tahoe. Lake Tahoe is a fabulous, welcome, and particularly folks from detailed their growth as individual groups wonderfully scenic location for a lake Arizona and Nevada. Details will be and how through their efforts together management conference and has been the posted as they become available on the they’ve crafted a plan to improve water focus of a great many research efforts for newly resurrected CALMS Seb site: quality within all six lakes in their over 40 years. The view from the meeting califonia-lakes.org. Submitted by: Doug watershed. facility was so captivating that the drapes Ball As part of the conference, ILMS had to be closed during the presentations conducted their annual meeting where in an attempt to keep people focused. Indiana Lakes Management ILMS members elected new board The meeting followed the traditional Society (ILMS) members Nate Bosch of Kosciusko Lakes CALMS pattern of having technical The Indiana Lakes Management and Stream and Grace College and Matt sessions during the first day and a field Conference occurred on March 25-27, Kerkhof of Hoosier Aquatic Management, trip on the second. The technical sessions 2010 at Merrillville’s Radisson Star Inc. Additionally, Laura Esman of Purdue featured presentations from some of the Plaza. More than 130 lake residents and University and Carrie Pintar of V3 many people involved with research enthusiasts joined the Indiana Lakes Companies Limited were elected secretary activities at Lake Tahoe and covered a Management Society for the 22nd annual and treasurer of the society, respectiviely. range of topics including nutrient loading conference. ILMS would like to thank out-going board and sources, wetlands restoration, non- This year’s conference highlighted members Gary Doxtater of the Indiana native warm water fishes, and other the differences between Indiana’s inland Wildlife Federation and Eileen Boekestein invasive species. Of particular interest lakes and our Great Lake, Lake Michigan of Kosciusko Lakes and Stream for all of were discussions of boat inspection with a theme of All Lakes Great and the efforts during their time on the board. protocols to retard introduction of Small. Karen Rodriquez of the USEPA’s Additionally, ILMS members voted to invasive species and potential control Great Lakes National Protection Office sign on to Indiana Wildlife Federation’s measures for Asian Clams (Corbicula served as the keynote speaker. Karen Phosphorus Free Resolution. The resolution sp.), which have recently been discovered highlighted the vast size and diversity is the first step in IWF’s campaign to enact in Lake Tahoe. Over the last couple of the Great Lakes habitat and detailed legislation banning the unnecessary use of of years, CALMS meetings have been methods by which the Great Lakes can phosphorus fertilizers statewide. largely devoted to discussions on invasive be improved through the Great Lakes At their annual banquet, ILMS was species (primarily Dreissenid mussels) as Restoration Initiative and the Great pleased to recognize the Tippecanoe those of us in the West are coming to grips Lakes Action Plan. Technical sessions Watershed Foundation for its long-term with the issues that have plagued many of focused on building partnerships, water efforts to improve water quality in Lake our colleagues in the East and Midwest quality assessment and monitoring, Tippecanoe and its 114 square mile for the last couple of decades. watershed improvement opportunities, watershed. TWF began work in their The annual membership meeting took in-lake assessment and opportunities for watershed in 1997. Since that time, place after the technical sessions and a near-shore and in-lake improvements, they’ve implemented over 50 projects new slate of officers and directors was emerging issues in Indiana, and concerns totaling more than $2 million including elected. It was also decided that CALMS relating to water control structure streambank restoration, wetland restoration, would grant two $1000 scholarships for maintenance and lake water levels. sediment trap creation, filter strip students in aquatic sciences. Attendees highlighted a partnership installation, livestock restriction, storm Day two was occupied by a field presentation by three lake associations: drain improvement, shoreline restoration, trip to both a constructed wetland and a Beaver Dam/Loon Lake Conservation and rain garden installation.

Summer 2010 / LAKELINE 45 ILMS also recognized Bill Jones profit-motivated organizer. Furthermore, from Indiana University SPEA for his depleted training budgets make it essential volunteer efforts and service to lakes that the cost of this training be kept at a throughout the state and honored their first minimum. With a goal of merely breaking recipient of the Legislative Achievement even financially, only a non-profit can Recognition Award, former State Senator provide the needed administration at Robert Meeks. Submitted by Sara Peel a cost intended to produce an optimal participation level. Oregon Lakes Association Initial responses to the Workshop OLA was organized well enough announcement are promising, and OLA in 1990 to convene its first annual is hopeful of continuing in this new role conference. These meetings have been of facilitating the promotion of Oregon regular events in the ensuing years but lakes. Submitted by Roger Edwards. they have retained much of the simplicity of that first gathering, when a diverse group of people with an attraction to lakes got together to talk about their common interest. The principal purpose of OLA, then and now, is to maintain a focus on lakes by providing a means to keep these diverse factions connected. There is a modest list of other achievements that OLA has fostered during the past 20 years, and it appears that yet another might be added when OLA hosts a Harmful Algal Bloom Workshop in May. Public knowledge about cyanobacteria toxins, and to the threat they pose, continues to increase, with health advisories warning people away from popular lakes and beaches, and water utility concerns about safeguarding domestic supplies. The May Workshop is not the first on this topic that OLA has held, but our role in this meeting is an expansion of the scope of previous OLA activities. On this occasion, OLA was able to enlist the knowledge and services of two experts in the field, both of whom are also OLA members: Dr. Wayne Carmichael, professor emeritus at Wright State University and Dr. Theo Dreher of Oregon State University. The Workshop is a joint undertaking of OLA, the Public Health Division of the Oregon Department of Human Services, and Oregon State University. This partnership between state agencies and a private non- profit group is mutually beneficial. The objectives of all parties are advanced, the simple decision process of the non-profit permits short time lines, and the resources of the state agencies bring credence to the event. OLA’s part in this endeavor is pivotal. While there is a perceived target audience for HAB training, the numbers of this group are not large enough to attract a

46 Summer 2010 / LAKELINE Literature Search Bill Jones

Canadian Journal of Fisheries and Sayer, C.D., T.A. Davidson, J.I. Journal of Plankton Research Aquatic Sciences Jones and P.G. Langdon. 2010. Caneiro, R.L., M.E.V. dos Santos, Maezo, M. J.o.s., H. Fournier and B. Combining contemporary ecology and A.B.F. Pacheco and S.M.F. de Oliveria E. Beisner. 2010. Potential and realized palaeolimnology to understand shallow e Azevedo. 2009. Effects of light interactions between two aquatic lake ecosystem change. Freshwater Biol intensity and light quality on growth and invasive species: Eurasian watermilfoil (55): 487-499. circadian rhythm of saxitoxins production (Myriophyllum spicatum ) and rusty in Cylindrospermopsis raciborskii crayfish ( Orconectes rusticus ). Can J Sayer, C.D., A. Burgess, K. Kari, T.A. (Cyanobacteria). J Plankton Res (31): Fisheries Aquat Sci (67): 684-700. Davidson, S. Peglar, H. Yang and N. Rose. 481-488. 2010. Long-term dynamics of submerged Canadian Journal of Physiology and macrophytes and algae in a small and Journal of the American Water Pharmacology shallow, eutrophic lake: implications for Resources Association Labine, M.A. and G.Y. Minuk. 2009. the stability of macrophyte-dominance. Newbold, J.D., S. Herbert, B.W. Sweeney, Cyanobacterial toxins and liver disease. Freshwater Biol (55): 565-583. P. Kiry and S.J. Alberts. 2010. Water Can J Physio Pharma (87): 773-788. quality functions of a 15-year old riparian Sayer, C.D., T.A. Davidson and J.I. Jones. forest buffer system. J Am Water Resour Fundamental and Applied Limnology 2010. Seasonal dynamics of macrophytes Assoc (46): 299-310. Tátrai, I., K. Mátyás, J. Korponai, P. and phytoplankton in shallow lakes: a Pomogyi, A.I. György, M. Havasi and eutrophication-driven pathway from Roelke, D.L., L. Schwierzke, B.W. T. Kucserka. 2009. Changes in water plants to plankton? Freshwater Biol (55): Brooks, J.P. Grover, R.M. Errera, T. clarity during fish manipulation and 500-513. W. Valenti and J.L. Pinckney. 2010. post-manipulation periods in a shallow Factors influencing Pyrmnesium parvum eutrophic lake. Fund Appl Lim (174): 135- Sondergaard, M., L.S. Johansson, T.L. population dynamics during bloom 145. Lauridsen, T.B. Jorgensen, L. Liboriussen initiation: results from in-lake mesocosm and E. Jeppesen. 2010. Submerged experiments. J Am Water Resour Assoc Freshwater Biology macrophytes as indicators of the (46): 76-91. González, M.J., L.B. Knoll and M.J. Van- ecological quality of lakes. Freshwater ni. 2010. Differential effects of elevated Biol (55): 893-908. Lakes and Reservoirs: Research and nutrient and sediment inputs on survival, Management growth and biomass of a common larval Journal of Applied Ecology Filstrup, C.T., S.J. Thad, J.D. White fish species ( Dorosoma cepedianum ). Angeler, D.G. and W. Goedkoop. 2010. and O.T. Lind. 2010. Use of sediment Freshwater Biol (55): 654-669. Biological responses to liming in boreal elemental and isotopic compositions to lakes: an assessment using plankton, record the eutrophication of a polymictic Lund, S.S, F. Landkildehus, M. macroinvertebrate and fish communities. J reservoir in central Texas, USA. Lakes Sondergaard, T.L. Lauridsen, S. Appl Ecol (47): 478-486. Reservoirs Res Manage (15): 25-39. Egemose, H.S. Jensen, F.O. Andersen, L.S. Johansson, S. Liselotte, M. Ventura Kovalenko, K.E., E.D. Dibble and J. and E. Jeppesen. 2010. Rapid changes G. Slade. 2010. Community effects of William (Bill) Jones , CLM, is LakeLine ’s in fish community structure and habitat invasive macrophyte control: role of editor and a former NALMS president. He distribution following the precipitation invasive plant abundance and habitat can be reached at Indiana University’s of lake phosphorus with aluminum. complexity. J Appl Ecol (47): 318-328. School of Public and Environmental Freshwater Biol (55): 1036-1049. Affairs, Room 347, 1315 E. Tenth Street, Journal of Fish Biology Bloomington, IN 47405-1701; (812) 855- McEwen, D.C. and M.G. Butler. 2010. Gozlan, R.E., J.R. Britton, I. Cowx and 4556; e-mail: [email protected]. x The effects of water-level manipulation G.H. Copp. 2010. Current knowledge of on the benthic invertebrates of a managed non-native freshwater fish introductions. J reservoir. Freshwater Biol (55): 1086-1101. Fish Biol (76): 751-786.

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