Dr. Susan Ziegler

Canada Research Chair

Casting light on dead zones

Worldwide, there are at least 146 dead zones areas of water too low in dissolved oxygen to sustain life. Dead zones range in size from small sections of coastal bays to large seabeds spanning some 70,000 square kilometres. What is killing fish and other living organisms in these coastal areas? Although a complex chain of events is to blame, nutrient enrichment created by human activities within watersheds trigger the formation of these zones.

Memorial Universityís new Canada Research Chair in Environmental Science, Dr. Susan Ziegler, will look at the impacts of environment change on aquatic ecosystems. Dr. Zieglerís appointment was announced at the University of Prince Edward Island June 27, 2005 in the latest round of Canada Research Chairs.

ďDr. Zieglerís research will explore how changes in land use, climate, solar radiation, and nutrient enrichment, which represent major forms of environmental change, impact aquatic ecosystems globally,Ē said Dr. Christopher Loomis, vice-president (research) at Memorial University.

Nutrient enrichment, caused by atmospheric deposition, agriculture and forestry practices, urban runoff, and sewage, is considered the primary stressor altering the biogeochemistry of the aquatic environment and potentially causing coastal dead zones worldwide. Micro-organisms drive aquatic biogeochemical processes, the cycling of critical elements within our environment. Dissolved organic matter (DOM) is the primary source of energy fueling microbial activity in the aquatic environment and is therefore critical to biogeochemical cycling in these ecosystems.

The impact of environmental change on nutrient and DOM cycling within the continuum from headwater streams to coastal marine ecosystems will be the focus of Dr. Zieglerís research program. Her research will initially focus on multiple streams within contrasting watersheds to investigate the interrelated impacts of nutrient enrichment and solar UV radiation on DOM biogeochemistry. Future efforts will be aimed at linking watershed processes to the biogeochemistry of coastal ecosystems. Dr. Zieglerís research will impact both the fields of aquatic biogeochemistry and global climate change by explaining how environmental impacts within watersheds alter both an ecologically and globally significant carbon reservoir. In addition to elucidating the ecological function of watershed ecosystems, this research program will build educational and research opportunities fostering multidisciplinary collaborative environmental science within and outside Atlantic Canada.