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Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6 ” x 9” black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. Bell & Howell Information and Learning 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 800-521-0600 UMI' WATER COLUMN PRODUCTIVITY, CALCITE PRECIPITATION, AND PHOSPHORUS DYNAMICS IN FRESHWATER MARSHES DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Michael A. Liptak, B.S. ***** The Ohio State Umversity 2000 Dissertation Committee: Approved by Professor William J. Mitsch, Adviser Professor David Culver Professor Samuel Traina / Adviser Environmental Science Graduate Program UMI Number: 9994897 UMI* UMI Microform 9994897 Copyright 2001 by Bell & Howell Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. Bell & Howell Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 ABSTRACT Algal photosynthesis and respiration can cause significant diurnal changes in water chemistry', and can increase pH enough to cause precipitation of calcium carbonate minerals. During the precipitation of calcite (CaCOp other chemical species such as phosphorus (P) can sorb onto the newly forming crystals and thus be removed from the water column. While calcite precipitation and subsequent P removal have been studied extensively in lakes, rivers, and streams, they have not been studied in temperate wetlands. Calcite precipitation and associated P removal were examined in two full-scale I -ha created experimental fi-eshwater marshes and in twenty 1 -m’ experimental mesocosms in central Ohio. Water, algae, and sediment samples were taken from July 1998 to May 1999 at sites from the inflow to the outflow of the marshes. Diurnal dissolved oxygen data taken every half-hour firom July 1996 through December 1998 at the experimental marshes were used to estimate gross primary production (GPP), respiration (R), and net primary production (NPP). NPP, GPP and R showed strong seasonal changes, with maxima in the summer (3.43 to 6.23 g O, m'^ d ') and minima (0.36 to 2.10 g O, m‘‘ d ') in the winter. Summer GPP values were similar to values for eutrophic hardwater lakes, indicating that the shallow euphotic zone of wetlands can be as productive on an areal basis as deeper euphotic zones in lakes. Summer GPP values in the middle subbasins were not significantly different between the planted and unplanted wetland in 1996 or 1998, but were significantly higher in the planted wetland in 1997. Conductivity and temperature data were used in conjunction with hydrologie data to develop budgets for total dissolved solids (TDS). Retention of total dissolved solids ranged from -0.7 to 12.7 Mg ha ' yr‘‘ (-0.4 to 13.5 percent retention, respectively) and averaged 7.9 Mg ha ' yr ' (6.3 percent retention). The two wetlands were not significantly different in total or percent retention fi'om 1996 to 1998; however, Wetland 2 had higher total and percent retention in 1996 and 1997, while Wetland 1 had higher total and percent retention in 1998. The total dissolved solids budget showed that the wetland acted as sinks for dissolved materials, consistent with calcite precipitation. Calcite saturation indices were positive for all water samples, indicating that calcite precipitation is thermodynamically favored. Ca and P concentrations decreased fi'om inflow to outflow, and calcite and dolomite were found in the algal biomass, as well as in the wetland sediments, while suspended sediment samples fi’om the river inflow did not contain significant amounts of calcite, indicating that the calcite precipitated in the wetlands and was not imported as suspended riverine sediments. Dolomite may have been imported via the river inflow. Total calcite in both basin sediments increased by an estimated 4.5 metric tons ha ' yr ' and and dolomite by over 1.4 metric tons ha ' yr ' fiom 1994 to 1999. Scanning electron microscopy showed calcareous material encrusting algal filaments. The total amount of P associated with calcite was up to 47 percent of the total P contained in the algal mat, suggesting that P coprecipitation essentially doubled the P removal capability of the algal mat. Calcite precipitation was also investigated in twenty 380-L shallow-water (30 cm) mesocosms to determine whether calcite precipitation/dissolution occurred on a diurnal time-scale in wetlands, and whether sorption with calcite was a significant sink for P. Ten mesocosms were covered with black cloth to inhibit photosynthesis, while ten mesocosms were left uncovered and stocked with filamentous algae fiom the experimental marshes (major spp. Cladophora, Rhizoclonium, Hydrodictyon). Water, algal biomass and sediment samples were taken fiom June 1998 to May 1999. Saturation index values were always positive, showing that calcite precipitation was thermodynamically favored for both treatments on all sampling dates. Dissolved oxygen, temperature, pH, and saturation index iii showed strong diurnal patterns in the uncovered mesocosms, and less so in the covered mesocosms. Calcium, soluble reactive P, and total P showed no diumal changes in either treatment, but were significantly lower in the water column of the uncovered mesocosms. Calcite precipitation occurred in the algal mats of the uncovered mesocosms, and calcite in the algal mats increased by 6.55 ± 1.05 g-eq CaCO^ in the uncovered mesocosms over one growing season. There were no algal mats present in the covered mesocosms, and calcite and dolomite in all mesocosm sediments were not significantly different fi'om the initial soil samples. IV Dedicated to my wife, Heather ACKNOWLEDGMENTS There are a great number of people I wish to thank for their help, friendship and encouragement along my educational path. I would like to thank Dr. William Mitsch, my advisor, for his encouragement, patience, and intellectual support. 1 would like to thank my committee for their help, especially Dr. David Culver, for his comments on my manuscript. I would like to thank all the people who encouraged me as an undergraduate biology student, including Dr. Johan Gottgens, Dr. Bob Sinsabaugh, Dr. Bill Bischoff, Dr. Charles Creutz, and Dr. Phil Yeager. 1 would also like to thank Mr. Frank DeMarco, my high school biology teacher, and Mrs. Parker, the advisor of the Green Eco-team for encouraging my early interest in ecology. I would like to thank all the people who have helped me gather and analyze my samples and data over the past four years; without you my research would not have been possible. Sharon Johnson, Heather Liptak, Doug Spieles, Mike Brady, Greg Sablak, Kevin Mohler, Holly Montgomery, Melanie Ford, and Virginie Bouchard all provided invaluable assistance. Special recognition goes to Sharon Johnson, Heather Liptak, and Greg Sablak for assistance imtil the wee hours of the morning. Doug Beak and Dedra Woner are thanked for their invaluable assistance in sample analysis, particularly organic carbon analysis. Thanks to Billy Lindsey for training me on the proper use of the flame atomic absorption spectrophotometer. Thanks to Sandy Jones and Dr. Neil Smeck for help with the calcite and dolomite analyses, and to John Mitchell and Wietse van Gerven for their expert help with scanning electron microscopy and elemental analysis. VI The wetlanders of Kottman Hall are thanked for their assistance and for their cameraderie and friendship. Naiming Wang, Lisa Svengsouk, Sharon Johnson, Virginie Bouchard, Sarah Harter, Molly Bean, Terry LeMaster, Bill Acton, Randy Bruins, Doug Spieles, Changwoo Ahn, Erica Filippi, Janice Gilbert, John Gutrich, Dan Fink, Eric Lohan, Greg Sablak, Amie Gifford, Holly Montgomery, Melanie Ford, Megan Hunter, Mike Brady, Matt Cochran and Rikke Broennum. Thanks to Bob Naim, wetlander emeritus, for taking the soil samples in 1993 and 1995 and for answering my questions about his procedures and results patiently. A special thanks to Doug Spieles, for making 378 Kottman Hall a fun place to be. Thanks to my family, who has supported me in all of my dreams and endeavors. Finally, and most importantly, thanks to my wife. Heather, whose love and understanding have kept me sane and happy throughout grad school. The first three years of my graduate studies were funded through a fellowship from