last updated: 15 October 2001

Daigo, Maria Joy

Maria Joy Daigo is a Ph.D. student of Swiss Federal Institute of Environmental Science and Technology (EAWAG), Limnology Department based in Kastanienbaum, Switzerland. EAWAG is an affiliate institute of Swiss Federal Institute of Technology (ETH - Zurich). Her research is about the effects of global warming and sustained nitrogen deposition on heterotrophic ecosystem processes in wetlands. Prior to joining EAWAG, Ms. Daigo worked for the Geological Survey of Japan, wherein she assisted a 2-year regional project on geoscientific map compilation.

Ms. Daigo holds a Bachelor of Science Degree in Biology, which she obtained in the Philippines, and a Master of Science in Environmental Technology and Management from the Asian Institute of Technology in Bangkok, Thailand. She also obtained a Master of Science in Applied Environmental Measurement Techniques at Chalmers University of Technology in Gothenborg, Sweden.

Research

Large-scale anthropogenic effects on ecosystem processes: litter decomposition and associated microbial productivity in littoral wetlands

The proposed project addresses the effects of major large-scale environmental changes caused by human activity on critical ecosystem-level processes. The considered anthropogenic effects are temperature increases and sustained nitrogen deposition. The strength of these effects will be tested by means of manipulative field experiments at the mesoscale. The examined system will be a littoral wetland dominated by the cosmopolitan, highly productive emergent macrophyte, Phragmites australis. The considered ecosystem-level processes will be litter decomposition (leaf blades, sheaths and culms), nutrient immobilization by the decomposing litter systems, microbial respiration (= carbon mineralization), and fungal and bacterial secondary production.

In a series of two experiments, both submerged processes on the sediment surface and aerial processes in the standing-dead plant canopy will be analyzed. In Experiment 1, littoral enclosures will be heated to temperatures of 2 and 4 °C above ambient water temperatures, and rates of the above ecosystem processes will be determined. Experiment 2 will examine the effects of increased nitrogen availability, both as a single factor and in combination with increased temperature (submerged processes) as well as altered phosphorus availability. The results of this series of experiments are expected to contribute significantly to an improved understanding of the mechanisms regulating submerged and standing-dead litter decomposition and associated microbial processes, and to facilitate predictions about the effects of global change scenarios on heterotrophic carbon flows in wetlands.

Keywords:
Global change, litter decomposition, microbial production, nutrient immobilization, fungi, bacteria, Phragmites australis, littoral wetland