Dominant algae of Otsego Lake, Cooperstown, NY

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1 Dominant algae of Otsego Lake, Cooperstown, NY Claire Garfield 1 INTRODUCTION The diversity and frequency of algal species are important factors in determining limnological conditions because algae serve as a biological indicator of ecological stability and water quality (Bellinger and Sigee 2010). While Otsego Lake is considered a meso-oligotrophic lake, data relating to the composition of the algal standing crop in Otsego Lake would be advantageous in further determining the state of the lake (Godfrey 1977). Certain species of algae are indicative of water quality. Some groups of diatoms (Bacillariophyceae) and golden-brown algae (Chrysophyceae) grow only in relatively unpolluted water whereas cyanobacteria are more tolerant of pollution (Baker 2012). Therefore the relative abundance of any given group of algae can reveal much about the health of a lake (Bellinger and Sigee 2010).The importance of knowing the taxonomic composition of algae in Otsego Lake is augmented by the fact that many genera of cyanobacteria, often referred to as blue-green algae, produce toxins as secondary metabolites involved in storing nitrogen (Baker 2012). Many of these toxins are neuro- or hepatotoxins. Beta-Methylamino-L-alanine (BMAA), a toxin capable of being produced by multiple species of cyanobacteria has been linked to amyotrophic lateral sclerosis (ALS) or Lou Gehrig s disease (Cox et al. 2003). The purpose of this study was to identify and determine the relative dominance of major planktonic algal taxa in Otsego Lake using both conventional microscopy as well as a Fluid Imaging Technnologies FlowCam, a digital particle analyzer (FlowCam 2011). METHODS Samples were taken bi-weekly at the deepest point (50m) in Otsego Lake, TR4-C (Figure 1). Two garden hoses attached to a weighted line were lowered to a depth of 20 meters and retrieved from the bottom, yielding a single composite sample. The contents of the hoses were emptied out into a one gallon Nalgene bottle made of high density polypropylene. 1 F.H.V. Mecklenburg Conservation Fellow, summer Present affiliation: Oneonta High School. Funding provided by the Otsego County Conservation Association.

2 Figure 1. Map of Otsego Lake showing the sampling site for algae. Samples were preserved with Lugol s iodine solution, which also later helped the algal cells settle out of suspension in Utermöhl chambers. The samples were stored in the cold room until further processing to prevent degradation of the algae.

3 Samples were analyzed in two ways: one with manual counts with an inverted microscope and another with FlowCam. Samples viewed with a microscope were inverted several times and placed in a 10-mL KC Denmark A/S Utermöhl chamber and viewed with the Zeiss Axiovert 25 inverted microscope. Cell counts were taken and recorded for the entire bottom area of the chamber. Samples viewed with FlowCam were analyzed as follows. Approximately 3mL of undiluted sample was processed through the flow cell. FlowCam then took images of the first 1000 particles. Those pictures were then identified and sorted into various libraries to be counted. FlowCam was much more proficient at identifying cells on new samples; however, on older samples, the microscope proved a better method. A function and asset of using FlowCam is that it can analyze data quickly and compensate for error involved in taking a subsample. However, using FlowCam did pose some problems. The most common pictures taken were either of detritus or non-algal particles, and the poor quality of many pictures prevented them from being used. Algae were counted by cell as opposed to colonies; however, Microcystis and Anabaena were counted by colony and filament, respectively. RESULTS AND DISCUSSION Table 1 summarizes the particle counts acquired using the microscope from samples collected from 21 April 2014 to 12 August 2015 (cell counts for most, colony counts for Microcystis and Anabaena). Similarly, Table 2 summarizes particle counts acquired using the FlowCam on samples collected from 19 May to 12 August Here, cells are not differentiated from particles (i.e., cells). Figure 2 and 3 summarize the microscope counts and FlowCam counts, respectively. Similarly, Figures 4 and 5 summarize the total counts using the microscope and FlowCam during the summer of 2015 (19 May to 12 August).

4 4/21/14 5/7/14 6/18/14 6/21/14 7/2/14 9/7/14 9/13/14 10/27/14 11/10/14 5/19/15 6/3/15 7/2/15 8/12/15 8/27/15 9/16/15 10/6/15 10/21/15 TOTAL MICROCYSTIS ANABAENA CYCLOTELLA ASTERIONELLA FRAGILARIA PINNATE DIATOMS DINOBRYON PERIDINIUM CERATIUM EUGLENA MOUGEOTIA GLOEOCYSTIS PEDIASTRUM Table 1. The total number of cells (#/ml) (except for Microcystis and Anabaena, which were counted as colonies) counted with the microscope, by genus and date.

5 5/19/15 6/3/15 6/7/15 7/2/15 7/14/15 8/12/15 TOTAL MICROCYSTIS ANABAENA CYCLOTELLA ASTERIONELLA FRAGILARIA PINNATE DIATOMS DINOBRYON PERIDINIUM CERATIUM EUGLENA MOUGEOTIA GLOEOCYSTIS Table 2. The number of particles counted with FlowCam for 2015 (#/ml) by genus and date. AMOUNT OF CELLS Microscope 4/21/14 5/7/14 6/18/14 6/21/14 7/2/14 9/7/14 10/27/14 11/10/14 5/19/15 6/3/15 7/2/15 8/12/15 GENERA Figure 2. The total number of cells (except for Microcystis and Anabaena, which were counted as colonies) counted with the microscope by genus and date.

6 120 FLOWCAM AMOUNT OF CELLS /19/15 6/3/15 6/7/15 7/2/15 7/14/15 8/12/15 0 GENERA Figure 3. The number of particles counted with FlowCam for 2015 by genus and date Microscope totals AMOUNT OF CELLS GENERA Figure 4. The total amount of cells counted manually by genus and date between 21 April and 27 August 2015.

7 AMOUNT OF CELLS FLOWCAM totals GENERA Figure 5. Represents total amount of particles counted by genus with FlowCam between 21 April and 27 August The most ubiquitous group of algae in Otsego Lake was Gloeocystis (Figure 6). Gloeocystis is a member of the subkingdom Chlorophyta. The value of Gloeocystis as a biological indicator is limited; however, large quantities, much larger than those of Otsego Lake, can cause an unpleasant smell (Guiry and Guiry 2015). Figure 6. Gloeocystis. Scale bar = 12.5 µm. The second most abundant species of algae in Otsego Lake was Mougeotia (Figure 7), a member of charophyceae. Mougeotia is spread throughout the world and is not considered a nuisance (Guiry and Guiry 2015).

8 Figure 7. Mougeotia. Scale bar = 12.5 µm. Dinobryon, a genus of Chrysophyceae (golden-browns), was also found frequently (Figure 8). Dinobryon is dependent upon oligotrophic conditions making it an excellent biological indicator. Thus the frequency of Dinobryon suggested a more oligotrophic lake (Baker 2012). Figure 8. Dinobryon. Scale bar = 12.5 µm. The most diverse group in Otsego Lake and all fresh water is Bacillariophyceae, commonly known as diatoms. Genera collected include Asterionella, Fragilaria, Cyclotella, and other unidentified pinnate diatoms. Specific genera of Bacillariophyceae have particular ecological preferences. The specificity and diversity of diatoms make them good biological indicators (Bellinger and Sigee 2010). The amount and diversity of diatoms suggested that Otsego Lake has fairly clean water.

9 The most common diatom was Fragilaria, a colonial genus that is intolerant of pollution (Bellinger and Sigee 2010). The high abundance of this genus suggested that Otsego Lake has relatively little pollution. Figure 9. Fragilaria. Scale bar = 12.5 µm. Photo by Kiyoko Yokota. While cyanobacteria were only found at low frequencies and with low diversity of genera, two genera, Microcystis and Anabaena, were found in Otsego Lake. Anabaena (Figure 10) can dominate in polluted, nutrient rich conditions, but the low density suggests good water quality. Microcystis also thrives in lakes with high phosphorous and nitrogen levels; thus, high densities might indicate cultural eutrophication (Baker 2012). The fact that few colonies of Microcystis were found indicates that nutrient loading is not yet a major problem to the health of the lake, but rather something to monitor for. While both are potentially toxin producing, microcystin and anatoxin from Microcystis and anatoxin from Anabaena, their presence is not a cause for concern because toxin production is strain specific, with not all cyanobacteria being dangerous (Dittmann et al. 2012) and because they were such minor components of the commubnity (Baker 2012). However, in the future, Microcystis counts may be higher because of the infestation of zebra mussels (Dreissena polymorpha); zebra mussels alter the plankton community, often favoring Microcystis (Vanderploeg et al. 2001). The increase in zebra mussels could promote the growth of Microcystis in Otsego Lake so monitoring the algal community composition would provide valuable data for addressing future issues.

10 Figure 10. Anabaena. Scale bar = 12.5 µm. CONCLUSION Algae monitoring is important for both environment and human health; certain types of algae can provide insight as to the state of habitats or potential production of deleterious toxins. Furthermore, analyzing algae is even more important in the face of environmental stressors and changes. With potential nutrient loading and the introduction of invasive species, algal composition could change significantly and continuing data collection could prove an important asset in addressing ecological problems. Based on the genera present and the amounts of the dominant genera in Otsego Lake, it can be inferred to be healthy and safe. REFERENCES Baker, A.L Phycokey -- an image based key to Algae (PS Protista), Cyanobacteria, and other aquatic objects. University of New Hampshire Center for Freshwater Biology Jul Bellinger E.G. and D.C. Sigee Freshwater algae: Identification and use as bioindicators. Chichester (West Sussex): Wiley-blackwell. Dittmann E., D. Fewer and B. Neilan Cyanobacterial toxins: biosynthetic routes and evolutionaryroots. Federation of European Microbiological Societies [Internet]. [cited 2015 Aug 19] /j x. Available from: file:///c:/users/garfc40/downloads/23.full.pdf FlowCam Manual. (3.0) [2011 Sept, cited 2015 Aug 4]. Available from:

11 Godfrey, P.J Otsego Lake limnology: Phosphorus loading, chemistry, algal standing crop and historical changes. In 10th Ann. Rept. (1978). SUNY Oneonta Bio Fld. Sta., SUNY Oneonta. Guiry, M.D. and G.M. Guiry. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. searched on 04 August Vanderploeg, H.A., J. R. Liebig, W.W. Carmichael, M.A. Agy, T.H. Johengen, G.L. Fahnenstiel, and T.F. Nalepa Zebra mussel (Dreissena polymorpha) selective filtration promoted toxic Microcystis blooms in Saginaw Bay (Lake Huron) and Lake Erie. Can J. Fish. Aquat. Sci. 58: