The BIG Picture Studying ecological issues with an eye toward larger spatial and temporal patterns has benefited Sophia Passy and her students in their research. One of their latest projects shows how wetlands can help streams affected by acidification in the Adirondacks. By Greg Pederson Brandon Wade Sophia Passy with some of the members of her lab, from left, master’s student Hongsheng Liu, biology instructor and recent Ph.D. graduate Katrina Pound, Passy, doctoral student Melissa Walsh and doctoral student Ben Anders. 28 <strong>Maverick</strong> <strong>Science</strong> <strong>2013</strong>-<strong>14</strong>
While small-scale experiments are important to science and often lead to major discoveries, when it comes to ecology it’s often necessary to take a wide-ranging and all-inclusive look at things to find solutions to complex problems. Macroecology — the study of relationships between organisms and their environment at large spatial scales to characterize and explain statistical patterns of species abundance, distribution and diversity — is what Sophia Passy uses to show how nature works. Passy, a UT Arlington associate professor of biology, has used the “big picture” approach in her research and it has helped lead to a better understanding of how one facet of a subject can affect many others. Passy has led numerous research projects utilizing a macro approach, including many environmental ecology studies which explore the response of algal communities to anthropogenic acidification, or acid deposition caused by human activities. One such study is an assessment of the effects of acidic deposition on streams in the eastern and central parts of the Adirondack Park in upstate New York. Passy is co-principal investigator of a three-year, $187,224 grant by the New York State Energy Research and Development Authority. The project’s principal investigator is Gregory Lawrence, a physical scientist with the U.S. Geological Survey’s New York Water <strong>Science</strong> Center with whom Passy has worked for years on several acid-related projects in the Adirondacks. One of Passy’s doctoral students, Katrina Pound, was lead author of a paper the team wrote about the research which was published in the September <strong>2013</strong> edition of the leading environmental and biodiversity conservation journal Global Change Biology. The study set out to determine if watershed wetlands can play a role in remediating the da<strong>mag</strong>e done to streams by acidification. “For over 40 years, acid deposition has been recognized as a serious international environmental problem, but efforts to restore acidified streams and biota have had limited success,” the researchers said in the Global Change Biology article. “The need to better understand the effects of different sources of acidity on streams has become more pressing with the recent increases in surface water organic acids, or ‘brownification,’ associated with climate change and decreased inorganic acid deposition.” “Acidification of surface waters from acid deposition is one of the most serious environmental problems in the northeast United States and northern Europe,” Passy said. “It is associated with biodiversity loss, elevated mortality, and simplified food webs. Despite numerous state and federal actions to reduce acid emissions, streams continue to experience acidification and biological communities have not returned to their pre-acidification state.” Passy, Pound and Lawrence, working with the USGS, carried out a large-scale study showing that wetlands are capable of improving stream ecosystem health in the Adirondacks, which is one of the most acid-impacted regions in the United States. “Wetlands are important not only for wellbuffered stream ecosystems as sources of iron, but also for acid-impacted streams because they contribute to the neutralization of aluminum, which reaches highly toxic concentrations in acid streams,” Passy said. “This research has far-reaching consequences for biodiversity conservation and stream management. It suggests that wetlands can be used in acid stream restoration and offers a viable alternative to the current approach for acidification remediation through liming, which is ineffective and even harmful.” For her dissertation research, Pound analyzed diatom communities from around 200 Adirondack streams that were sampled over four sampling periods. Diatoms are an environmentally sensitive group of algae and the most diverse microbial producers. Pound successfully defended her dissertation in August and received her Ph.D. in December <strong>2013</strong>. She is working as a biology lecturer and continuing to do research in Passy’s lab during the Spring 20<strong>14</strong> semester. “Studying this region is challenging because streams are acidified by both inorganic acid deposition and natural organic acidity originating from soils and wetlands,” Pound said. “My job was to count and identify the diatom species in each of the stream samples and examine the impact of these two sources of acidity on diatom diversity.” The current study is an extension of the 2003-05 Western Adirondack Stream Survey (WASS), a project for which Passy and her USGS collaborators received $486,000 from the New York State Energy Research and Development Authority. According to the USGS, the study found that acid rain had acidified soils resulting in toxic aluminum levels in two-thirds of 565 assessed streams. It also found that diatoms were moderately to severely affected by acid rain in 80 percent of assessed streams; aquatic insects and related organisms referred to as macroinvertebrates were moderately to severely affected in over half of assessed streams; and recovery from acidification had been minimal in 11 of 12 Adirondack streams sampled in the early 1980s. “By teaming up, we are able to address the problem of acid rain from a truly interdisciplinary perspective, myself being the soil and water chemist and Sophia being the expert in aquatic ecology, and in particular, diatoms,” Passy and her students analyzed water samples from streams such as this one in the Adirondack Forest Preserve. Photo courtesy of Sophia Passy. <strong>Maverick</strong> <strong>Science</strong> <strong>2013</strong>-<strong>14</strong> 29
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