My aquatic research initiatives center on the biology and ecology of freshwater algae. I have been assisted in my work by a long list of students, and I am indebted to them for their dedication and accomplishments. Currently, I am working on the following research initiatives, all of which examine algae in the environment.
Dinofagellate Studies:
I have been seeking environmental cues for occurrence and the onset of reproduction of many different freshwater dinoflagellates, particularly species of Peridinium. Although laboratory manipulations can successfully induce sexual reproduction in most Peridinium species, they do not translate well to understanding the actual onset of sexual reproduction and cyst formation in local environments. Such an understanding of these species might help to explain why they serve as good environmental indicators of the health of ponds and lakes that might be susceptible to acid precipitation. (A long list of former students including Jeff Merrell and David Seaborn).
Creek Studies:
I have been studying the local creeks (Middle Creek and Penns Creek) since 1997. In this case, I have been using diatoms as environmental indicators of the health and heterogeneity of the creek environments. More recently I have collaborated with Dr. Jeff Graham of the Department of Mathematics to examine attached diatoms in Penns Creek and evaluating their species diversity on rocks as a function of area according to The Theory of Island Biogeography. I have initiated a series of in situ experiments using ceramic tiles as surrogate rocks to explore the species-area relationships, attached algae community structure, and the dynamics of succession in attached algal communities. Furthermore, this experimental design can also explore aspects of competition. Former students include: Jen Wolny, Todd Stem, Todd Edgerton, Drew Hardick, Matt Wargo, Sarah Kiemle, Sidra Blake, Tom Leonard, Jill Sands, and Chris Resch.
River Studies:
I have begun to explore the impacts of local streams on the Susquehanna River. Shamokin Creek, an acid mine impacted stream, flows into the Susquehanna River just below Sunbury. The creek water does not simply dilute into the river. Rather, because of the resistance to lateral mixing in the Susquehanna River, the chemical and physical signatures can be measured more than 3 kilometers downstream from the confluence. Attached algae are used as a means to provide an integrated temporal view of the extended impact of Shamokin Creek. In the future I would like to explore other parts of the Susquehanna River to examine the impact of the heat plume from the Shamokin Dam power plant, the effluent plume from the Selinsgrove sewage treatment plant, etc. Meagan Brennan, Humi Pai, and Laura Wirpsza worked with me on this project.
Acid Mine Impaired Streams:
Work at the mouth of Shamokin Creek in the Susquehanna River prompted me to begin studying the influence of Acid Mine effluent on Shamokin Creek. The water during most of the year is stained orange from the Specifically, I have been interested in the biofilm that develops on rocks and other substrates in the stream. The biofilm is made of attached algae, many of which are diatoms, and bacteria. These communities, though not very diverse, are quite robust and pervasive throughout the stream. Thus, their occurrences indicate that the acid mine impact exists throughout the stream, even in areas where mitigation has been attempted. Thus, a baseline of these communities through the seasons should provide a measure against which the success future mitigation attempts can be measured. Furthermore, the biofilms, themselves, may hold the keys to understanding how to repair such impaired streams. This summer, I will begin a project with Dr. Tammy Tobin-Janzen (environmental microbiology) and Dr. Chris Janzen (environmental inorganic chemistry) to further explore the nature of the biofilms in Shamokin Creek. This year Nicole Sweeney and Laura Wirpsza worked with me on this project.
Pond and Lake Studies:
I have been interested in the biology and ecology of freshwater phytoplankton, particularly as they inform an integration of the ecological health of particular environments. I have had projects that look at ponded wetlands, impoundments, and natural lakes. As a consequence of that work, I have generated a Pond Management Key. The current work in lake studies is a ten-year study of Galich Lake, a glacial lake in central Russia. I have used phytoplankton as indicators to inform advice to local governments as to the causes of current environmental trends in the lake and what steps might be taken to mitigate current problems. Former students include: Brian Anderson, Josh Affrime, Charlotte Murray, and Megan Ferguson. Students who have helped with the Galich Lake study include: Josh Affrime, Elisa Swartz, Tom Leonard, Ashley Shade, Greg Schwartzentruber, Angela Forgues, Erin Rackovan, Stacy Panova, and Lauren Miller.
Algae as Environmental Indicators:
Algae and their occurrence represent an integrated response to ambient physical and chemical conditions in natural waters. This makes them far more useful to describe aquatic environments than periodic chemical samples that provide “snap shots” of conditions.
Why algae?
Algae are small, usually with all cells directly exposed to the surrounding environment. Therefore, the occurrence of particular calibrated algal species represents an integrated range of temperature, pH, oxygen, nitrate, ammonium, phosphate, etc. over the life of the algal population. Algae grow rapidly, particularly when compared to vascular plants and animals. Their response to fluctuations in conditions also is rapid, on the order of days and weeks rather than months and years. Algae are nearly universal in their distribution. Thus, the occurrence or absence of particular taxa is a consequence of environmental factors rather than geographic range as in animals and vascular plants.
Currently, I am involved in calibrating species (genera or higher taxa are not useful) of phytoplankton in local lakes and attached algae in local streams. See the algal image archive.
On-Line Projects: The Algal Image Archive (initiated by Matt Wargo) Saturday Science (For this project I have collaborated with other scientists and faculty in education.)