2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/27/2021 | 2:00 PM - 3:30 PM | Assessing the relative importance of canopy gaps, macronutrient availability, and molybdenum additions on chlorophyll-a accrual in forested headwater streams | Virtual Platform
Assessing the relative importance of canopy gaps, macronutrient availability, and molybdenum additions on chlorophyll-a accrual in forested headwater streams
Primary production is a key driver of aquatic nutrient cycling and provides a vital energy source for stream food webs. Dense canopy cover often limits primary production; however, in streams with canopy gaps, the limitation can shift from light to nutrients. Although much research has assessed effects of light and macronutrients (N, P) on primary production in headwater streams, few studies have explored co-limitation considering light as a spatially heterogeneous resource or potential micronutrient limitations. To explore the role of canopy gaps in creating macro and micronutrient limitation hotspots, we deployed nutrient diffusing substrates (NDS) along 12 forested headwaters, 9 in the Cascade Range, OR and 3 in the White Mountains, NH. Within each stream, we deployed 6-9 NDS arrays with replicate control and +NP cups. Arrays were placed in shaded and gap areas, and chlorophyll-a was measured after 3-4 weeks. We also included Mo treatments as this micronutrient is required for N-fixation and may increase chlorophyll-a by alleviating N demand. Results suggest an association between background nutrient concentration and difference in chlorophyll-a in gaps versus shade for both control and +NP substrates, although Mo additions caused no observed increases.
- Nutrients
- Biogeochemistry
- Land use
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Presenters/Authors
Allison Swartz
(), Oregon State University, allison.swartz@oregonstate.edu;
ASHA DISCLOSURE:
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Dana Warren
(), Oregon State University, dana.warren@oregonstate.edu;
ASHA DISCLOSURE:
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