Low‐level addition of dissolved organic carbon increases basal ecosystem function in a boreal headwater stream
| Autor: | Jeffrey A. Back, Dennis F. Whigham, Caleb J. Robbins, Ryan S. King, Alyse D. Yeager, Coowe M. Walker, Robert D. Doyle |
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| Rok vydání: | 2017 |
| Předmět: |
0106 biological sciences
010504 meteorology & atmospheric sciences periphyton Wetland 01 natural sciences lcsh:QH540-549.5 Dissolved organic carbon Ecosystem Periphyton Ecology Evolution Behavior and Systematics organic matter 0105 earth and related environmental sciences Kenai Peninsula geography Biomass (ecology) geography.geographical_feature_category experiment Ecology 010604 marine biology & hydrobiology Primary production Food web resource subsidies Environmental science lcsh:Ecology Ecosystem respiration Alaska |
| Zdroj: | Ecosphere, Vol 8, Iss 4, Pp n/a-n/a (2017) |
| ISSN: | 2150-8925 |
| DOI: | 10.1002/ecs2.1739 |
| Popis: | Comprehension of basic stream ecosystem function relies on an understanding of aquatic–terrestrial linkages. One major component of such linkages is the incorporation of landscape‐derived energy and nutrients into the aquatic food web via microbes. In many boreal streams, wetlands and alder are known to be primary sources of dissolved organic carbon (DOC) and dissolved inorganic nitrogen (DIN), respectively. To simulate the influence of the highly labile portion of wetland‐derived DOC subsidies on microbial production and ecosystem processes in a stream with high landscape‐derived nutrient inputs, we enriched a boreal headwater stream situated in a high‐alder, low‐wetland cover catchment (i.e., high DIN, low DOC) with low levels (~0.25 mg/L) of labile DOC (as acetate‐C) for 9 weeks. We compared nutrient uptake, bacterial biomass production, and photosynthesis of periphyton and ecosystem metabolism in physicochemically similar upstream (reference) and downstream (treatment) reaches. DIN uptake was greater in the treatment than in reference reach on six out of nine dates during the dosing period. Bacterial biomass production positively responded to C enrichment. Ecosystem respiration increased up to ~50% after dosing began. Gross primary production responded positively to DOC enrichment early in the study when riparian vegetation did not limit light availability, but negatively later on in the growing season. We conclude that even low levels of labile DOC may act as a strong subsidy to headwater stream ecosystems, particularly those with high levels of DIN inputs from alder. Headwater streams influenced by high contributions of both alder and wetlands may represent biogeochemical hotspots, and these landscape features should be viewed as vital and complementary in their roles for ecosystem function. |
| Databáze: | OpenAIRE |
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