2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/21/2019 | 3:15 PM - 3:30 PM | RESOURCE LIMITATION OF AUTOTROPHS AND HETEROTROPHS IN BOREAL FOREST HEADWATER STREAMS | 250 AB
RESOURCE LIMITATION OF AUTOTROPHS AND HETEROTROPHS IN BOREAL FOREST HEADWATER STREAMS
Permafrost loss at high latitudes alters watershed flowpaths and is predicted to increase nutrient input to streams. Changes in water chemistry and energy supply can significantly impact stream food webs. Within biofilm communities, autotrophs and heterotrophs compete for inorganic nutrients with the outcome dependent on temperature, light availability, and dissolved organic matter (DOM) lability. In Interior Alaska, sub-catchments are underlain with varying permafrost extents, creating an ideal location to quantify impacts of permafrost thaw and resulting variation in water chemistry. Our objective was to determine how changes in resources influence competition between autotrophs and heterotrophs in boreal stream biofilms. We predicted that with abundant light and labile DOM, inorganic nutrients would dictate autotrophic and heterotrophic activity and biomass, but with low light and recalcitrant DOM, inorganic nutrients would become secondary controls. Through nutrient diffusing substrata deployment and in-lab metabolism incubations, we found that inorganic nutrients and labile carbon limited heterotrophs. Autotrophs were limited by light, but in high light were limited by inorganic nutrients. When labile carbon and inorganic nutrients were available, heterotrophs outcompeted autotrophs for inorganic nutrients, and under elevated light, increases in algal carbon supported higher heterotrophic respiration.
- Bacteria
- Organic Matter
- Algae
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Presenters/Authors
Sophie Weaver
(), University of Alaska Fairbanks, saweaver2@alaska.edu;
ASHA DISCLOSURE:
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Jeremy Jones
(), University of Alaska Fairbanks, jbjonesjr@alaska.edu;
ASHA DISCLOSURE:
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