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Studying Freshwater Ecosystems
Studying Freshwater Ecosystems


Roughly 0.3% of earth's freshwater is contained in lakes, rivers, and swamps where it is most easily available to support the needs of human populations. Many of our activities place enormous stress on these ecosystems. Pollution, the introduction of invasive species, climate change, and water infrastructure are altering the physical and biological makeup of waterways large as the Columbia and small as spring-fed ponds in the Cascades. The effects of these stressors are damaging, sometimes devastating to the quality of water and life.

Dr. Angela Strecker, Assistant Professor, Environmental Science and Management, joined the faculty of PSU in 2011. Her research blends applied and theoretical approaches to the investigation of how aquatic ecosystem function and services are influenced by human activities. Before arriving at PSU, she held postdoctoral fellowships at the University of Toronto and the University of Washington, respectively. Dr. Strecker received her Ph.D. in Biology from Queen's University in Kingston, Ontario.

"Humans are changing the environment," said Dr. Strecker, "adding stressors that influence ecosystems in different ways. Our goal in the lab is to learn more about the effects of these combinations of different stressors on organisms in aquatic ecosystems. We study food webs, fish, invertebrates, algae—the whole gamut of different species in aquatic ecosystems."

Dr. Strecker's research examines the influences of invasive species and climate change on biodiversity and ecosystem function. Using the tools of spatial ecology she can investigate the importance of scale in communities of organisms inhabiting lakes and rivers. And by collecting quantitative data on the distribution of species in water systems modified and regulated by infrastructure such as dams, canals, and pipes, she can help government agencies and other organizations identify areas where conservation efforts should be focused. 

Current studies underway in the Strecker Aquatic Ecology Laboratory include an examination of mercury bioaccumulation in Cottage Grove Reservoir in the Willamette Valley. In another, one of Dr. Strecker's students is researching nitrogen stressors in lakes, some stocked with fish and some not, near Mt. Rainier National Park. There is also a study of species migration by means of manmade infrastructure in the Columbia River where species travel between once isolated ecosystems using some 300 miles of canals in a small area in Eastern Washington.

"Freshwater habitats are some of the most threatened globally," Dr. Strecker said. "Water diversions. Withdrawals. A lot of environmental stressors end up focused down on freshwater systems. What happens on the land gets transferred into the water. So understanding better ways to conserve these ecosystems and better ways to mitigate our actions on the landscape are why I feel it's important to study these systems."

The rivers, lakes, and organisms that are the focus of Dr. Strecker's research are parts of a complex, interconnected system. Adjust the balance just a little and the health of the ecosystem begins to fail. Once that happens the quality of the water begins to drop. As Dr. Strecker points out, this is important to us because whole economies are based on high quality water: commercial fishing, recreation, power generation, not to mention the usage as drinking water.

"Water quality is one of our foremost concerns," Dr. Strecker said. "With climate change we're seeing less snowpack, which means less water in our lakes and rivers. This and fluctuations in water temperature are harming species, not all of which will be able to adapt to changing conditions. We know that more diverse ecosystems have better functionality and that functionality is essential to water quality."

The emphasis on water quality and its relevance to human concerns is indicative of a central force behind Dr. Strecker's choice in research projects.

"When I decide which questions I want to investigate, I always ask myself how society will directly benefit from the results of the study," Strecker said. In the case of her research to date, society has reaped great benefit. Studies she has led and participated in have produced numerous publications that add to the knowledge of the scientific community, knowledge which, in turn, informs policy makers and organizations dedicated to the conservation of freshwater species and ecosystems. Her research helps us understand the relationships between our activities and the health of the water systems we depend on. And in the Strecker Aquatic Ecosystems Laboratory, the next generation of scientists is preparing to tackle major issues like climate change, pollution, water quality and demand, the possible extinction of species dependent on fragile freshwater ecosystems, and the adaption of those species resilient enough to withstand the changing environment.

Authored by Shaun McGillis
Posted December 24, 2013