Effects of freshwater inflow on carbon dioxide exchange in a coastal wetland /
An anthropogenic factor impacting coastal wetlands is the diversion of freshwater and nutrients, such as occurred in salt marshes located at the upper end of the Nueces River Delta near Corpus Christi, Texas. The channelization of the Nueces River has diverted many of the hydrologic inputs. As a r...
| Main Author: | |
|---|---|
| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
2002.
|
| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=764786021&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | An anthropogenic factor impacting coastal wetlands is the diversion of freshwater and nutrients, such as occurred in salt marshes located at the upper end of the Nueces River Delta near Corpus Christi, Texas. The channelization of the Nueces River has diverted many of the hydrologic inputs. As a result of freshwater diversion, salinity in the estuarine marsh is high, productivity is low, and the marsh frequently dries up during the summer. A study was conducted to determine how daily and seasonal changes in net carbon dioxide exchange (NCE) are affected by water availability throughout the year, and how these changes impact productivity in the marsh. A tower-based micrometerological system was used to provide long-term measurements of the NCE of the salt marsh. The salt marsh was a source for CO₂ when water was limiting and vegetation was stressed and a sink for CO₂ when fresh water was available, indicating the importance of fresh water to primary productivity in the marsh. A stress index can be effectively used to determine the effects of individual freshwater additions on NCE. Freshwater additions affected NCE primarily through their impact on photosynthesis. Annual average daily respiration was not affected by water availability. When ecosystem respiration was divided into its above- and belowground components, above-ground respiration, composed primarily of maintenance respiration and photorespiration, was approximately 80% of total ecosystem respiration. As maintenance respiration is fairly constant, the dominance of above-ground respiration could account for the stability in annual average daily respiration. To restore marsh productivity, freshwater additions should be made when stress is low and plants are actively photosynthesizing. |
|---|---|
| Item Description: | Vita. "Major Subject: Soil Science". |
| Physical Description: | xii, 81 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 71-80). |