QUANTITATIVE ANALYSES OF PERIPHYTON BIOMASS AND IDENTIFICATION OF PERIPHYTON TAXA IN THE TRIBUTARIES OF OTSEGO LAKE, NY IN RELA-riON TO SELECTED ENVIRONMENTAL PARAMETERS Stefanie H. Komorowski Biological Field Station Cooperstown, New York Occasional Paper No. 26. July, 1994 Biology Department State University College at Oneonta THIS MANUSCRIPT IS NOT A FORMAL PUBLICATION The information contained herein may not be cited or reproduced without permission of the author or the S.U.N.Y. Oneonta Biology Department. This contribution has been modified from a NYSDEC Bureau of Fisheries, Safety and Health Manual provided by Mr. George Seeley, NYSDEC Fish Propagation Unit. TABLE OF CONTENTS Abstract i Table of Contents. ............................................. iii Introduction Nutrient Concentrations 1 Water Quality 8 Physical Parameters 10 Macroinvertebrate Grazers 11 Seasonality . .. ......................................... 12 Sampling 13 Objectives .......................................... .......... .14 Methods Selection and Characterization of Streams 14 Description and Use of Artificial SUbstrates.. 15 Collection, Preparation, and Analysis of Samples 16 Monthly and Seasonal Average Data for Biomass and Parameters 18 Data Preparation .................................. ............. 18 Calculation of Bedrock and Soil Type Percents 19 Results Stream Characterization ...................................... .. 20 Biomass , 22 Factors Affecting Periphyton Growth 27 iii Periphyton Taxa 31 Identification of Bedrock and Soil Type in the Otsego Lake Watershed , 38 Land Use 40 Discussion Overview. .................................................. .. 42 Stream Characterization , 42 Affects of the Parameters on Periphyton Biomass 43 Identified Periphyton Genera and Their Seasonal Succession 59 Bedrock and Soil Correlations 62 Affects of the Streams on Otsego Lake ..................•.........64 References . 66 Appendices .• . ... ........•................. • . 71 iv ABSTRACT Nine tributaries to Otsego Lake, Otsego County, NY; and the Susquehanna River, its outlet, were studied to gain an understanding of the nutrient concentrations, periphytic biomass and taxa, and macroinvertebrate grazer populations. Specific streams were chosen based on the land use practices in their drainage basins. Four streams had watersheds dominated by agricultural activities. They generally had the highest yearly average of nutrient concentrations and periphyton biomass. The combined yearly averages of T-P04 equaled .057 mgtl, N03 equaled 1.08 mgtl, chlorophyll a equaled .691 mglm2/d, and ash-free dry weight equaled 133.86 mgtm2/d. Four other streams had watersheds that were primarily forested. They generally had a lower yearly average of nutrient concentrations and periphyton biomass. The combined yearly averages of T-P04 equaled .037 mgtl, N03 equaled .46 mgtl, chlorophyll a equaled .314 mgtm 2/d, and ash-free dry weight equaled 2 58.47 mgtm /d. One stream 'flowed through an urban area. The T-P04 yearly average concentration was high in this stream (.334 mgtl). Nitrate and biomass yearly averages were low (N0 3 equaled .37 mgtl, chlorophyll a equaled .032 mgtm 2/d, and ash-free dry weight equaled 16.28 mg/m2/d). Other parameters that were measured in the streams were chlorides, turbidity, velocity, and temperature. Temporal patterns were considered important factors affecting stream ecology throughout the year because our seasons vary greatly. The change of seasons initiated variations of nutrient concentrations and periphyton biomass and taxa. The highest seasonal averages of T.P04 and N03 in the agricultural streams occurred during the winter and in the forested stream in the summer. Periphyton biomass in the agricultural and forested streams was highest in spring. At the same time an increase in similar periphyton taxa communities and numbers of genera identified in each stream were found. The initiation of agricultural best management practices (BMP's) in the agricultural areas of the Otsego Lake Watershed will reduce the potential of soil erosion and high nutrient concentrations entering the lake. ii INTRODUCTION In order to study the primary productivity, biomass, and diversity of periphyton taxa in streams, it is essential to learn what factors influence periphyton and how they effect their ecology. In this work, nine tributaries to Otsego Lake, NY; 42 Q 43'N - 73Q 57'W (Iannuzzi 1991) and the Susquehanna River, its outlet, were studied (Figure 1). Factors that were considered influential to periphyton ecology included nutrient concentrations, water chemistry, physical variables, and macroinvertebrate population densities, all of which change seasonally throughout the year. The term periphyton has various definitions depending on the author. The meanings range 'from simple, •... microfloral growth upon substrata" (Wetzel 1983) to more complex, .... zoogleal and filamentous bacteria, attached protozoa, rotifers, and algae, and also the free-living microorganisms found swimming, creeping, or lodged among the attached forms" (American Public Health Association (APHA)1989). The definition best suited for trlis study includes the filamentous blue-green algae, filamentous green algae, and diatoms attached to artificial and natural substrates. Nutrient Concentrations Nutrient concentrations varied between the ten study sites due to storm events, land use practices in the stream basins, and characteristics of bedrock and soil type including soil erodability. Fluctuations of nutrient concentrations have an effect on the growth of periphyton. Land use practices dominant in the Otsego Lake Watershed are (9 ) ( 6) ( 5 ) ( 2 ) (1) SUSQCEHANNA RIVER Figure 1. Map of the Otsego Lake Watershed showing the names, locations, and numbers of the studied streams. 2 agriculture and forest as shown in Figure 2 (Sohacki 1974; Harman 1990; and Iannuzzi 1991). Streams flowing through these agricultural areas tend to have higher nutrient concentrations than streams flowing through forested areas. Singer ~ al.. (1975), Fuller (1987), and Bushong ~ .al., (1989) support this statement by suggesting that the fertilizers farmers use on the land will eventually reach the streams. Also, since the land has often been clear-cut for fields, less vegetation remains to incorporate the nutrients as they make their way to streams (Bushong mal., 1989). According to Bushong mal., (1989) the increase in nutrient concentrations of streams flowing through agricultural areas is reflected in the growth of periphyton. Sections of streams near cultivated fields usually have high densities and a large biomass of periphyton. Conversely, streams flowing through forested areas usually are well shaded and have lower nutrient concentrations because most of the vegetation surrounding them fix any nutrients that are released when a storm event occurs (Fuller 1987; Bushong mat., 1989; and McDiffett ~ al.. 1989). Urban land use is also present in the Otsego Lake Watershed. Wetzel (1983) stated that changes in urbanization are almost directly proportional to the increases in phosphorus concentrations of surface water. Sources of phosphorus include fertilizers from lawns, drainage water from storm sewers, and leaves (Wetzel 1983). This is a concern because one stream in this study flows through the Village of Cooperstown and high concentrations of nutrients enter the stream quickly during precipitation events (Albright 1993). Storm events influence periphyton growth, biomass, population densities, and taxa by adding nutrients to streams and by tearing old periphyton 3 '---I ! Iwaterbodies and wetlands settlements III agriculture ~:'::'~~forest and b~Jshland Figure 2. Map of the Otsego Lake Watershed showing land cover. (Modified from Harman 1990) 4 filaments from the substrate (Fuller 1987 and Bushong .e.t a.t.. 1989). Heavy rainfall causes the nutrient concentrations to increase by flushing the nutrients from the fields into the streams (Fuller 1987). This increase in nutrient concentration lasts for just a short time interval as described by McDiffett .e.t ai., (1989). As the storm continues, the nutrient concentrations increase followed by an increase in the discharge of the stream. The nutrient peak occurs before maximum discharge is reached. Once the peak is attained, the concentrations begin to decrease during the latter stages of the storm event because the nutrients, mostly from surface runoff, have been previously washed into the streams. Heavy rains cause strong currents and increase water velocities. In this situation algal mats are ripped away which results in a decrease in diatom populations and biomass of filamentous algae (Bushong .e.t ai., 1989; Horner .e.t at., 1990; Peterson .e.tai., 1990; and Dodds 1991). Biggs .e.tat., (1989) found that disruption of periphytic mats by floods occurred not only because of the shearing stress of the water velocity, but also from instability of the natural substrate, and scouring action of suspended solids. Algal species differ in attachment strength to the substrate depending on the current regime to which they are adapted (Horner .e.t ai., 1990). Diatoms can attach themselves to the substrate by a stalk, raphe, or mucilaginous pad to resist removal by strong currents (Stevenson 1982). The irregular surface of the natural rock substrate provides protection for diatoms and filamentous algae from the stress of water velocity (Nielson .e.t .al., 1984 and Peterson .e.t .al., 1990). Cladophora, a filamentous genus, has adapted to fast water velocities by exploiting