UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Aquatic ecosystem metabolism as a control of carbon transport in a managed forest Ngo, Trisa

Abstract

As the majority of Canada obtains its drinking water from forested watersheds, forest management to better address the effects of land use changes related to industries such as logging and urban development are of high public interest. To understand impacts on aquatic ecosystems from land use change it is essential to understand how carbon is cycled, transported, and stored throughout the ecosystem. Aquatic ecosystem metabolism (AEM), a key component of carbon cycling, can be evaluated by determining gross primary productivity (GPP) and ecosystem respiration (ER) within the water column of streams, rivers, lakes, and wetlands. AEM controls energy and material flow through aquatic ecosystems therefore linking environmental change and food webs to provide a useful framework for examining ecosystem function and productivity. The objective of this research was to investigate the role of AEM as a control on carbon transport, turnover, and fate in forested ecosystems under varying land use and streamflow conditions. The study was conducted in the University of British Columbia (UBC) Malcolm Knapp Research Forest (MKRF) located approximately 50 km east of Vancouver, BC containing forested and harvested blocks along a single 3.4 km stream reach containing four monitoring stations during late summer to winter 2022. This study examined the seasonal and spatial differences of AEM inputs and found that temporal and spatial disparities can have a significant effect on AEM and gas exchange rates at finer spatial scales. Overall, the stream reach demonstrated R exceeding GPP therefore indicating a negative net ecosystem production (NEP) and a heterotrophic stream reach. This study provides an exploratory investigation into AEM in a headwater stream of the Pacific Northwest.

Item Media

Item Citations and Data

Rights

Attribution-NonCommercial-NoDerivatives 4.0 International