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- Corman, Jessica R., et al.
(författare)
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Response of lake metabolism to catchment inputs inferred using high-frequency lake and stream data from across the northern hemisphere
- 2023
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Ingår i: Limnology and Oceanography. - : John Wiley & Sons. - 0024-3590 .- 1939-5590. ; 68:12, s. 2617-2631
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Tidskriftsartikel (refereegranskat)abstract
- In lakes, the rates of gross primary production (GPP), ecosystem respiration (R), and net ecosystem production (NEP) are often controlled by resource availability. Herein, we explore how catchment vs. within lake predictors of metabolism compare using data from 16 lakes spanning 39°N to 64°N, a range of inflowing streams, and trophic status. For each lake, we combined stream loads of dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP) with lake DOC, TN, and TP concentrations and high frequency in situ monitoring of dissolved oxygen. We found that stream load stoichiometry indicated lake stoichiometry for C : N and C : P (r2 = 0.74 and r2 = 0.84, respectively), but not for N : P (r2 = 0.04). As we found a strong positive correlation between TN and TP, we only used TP in our statistical models. For the catchment model, GPP and R were best predicted by DOC load, TP load, and load N : P (R2 = 0.85 and R2 = 0.82, respectively). For the lake model, GPP and R were best predicted by TP concentrations (R2 = 0.86 and R2 = 0.67, respectively). The inclusion of N : P in the catchment model, but not the lake model, suggests that both N and P regulate metabolism and that organisms may be responding more strongly to catchment inputs than lake resources. Our models predicted NEP poorly, though it is unclear why. Overall, our work stresses the importance of characterizing lake catchment loads to predict metabolic rates, a result that may be particularly important in catchments experiencing changing hydrologic regimes related to global environmental change.
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| 2. |
- Thayne, Michael W., et al.
(författare)
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Lake surface water temperature and oxygen saturation resistance and resilience following extreme storms : Chlorophyll a shapes resistance toward storms
- 2023
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Ingår i: Inland Waters. - : Taylor & Francis Group. - 2044-2041 .- 2044-205X. ; , s. 1-53
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Tidskriftsartikel (refereegranskat)abstract
- Extreme storms are becoming more frequent and intense with climate change. Assessing lake ecosystem responses to extreme storms (resistance) and their capacity to recover (resilience) is critical for predicting the future of lake ecosystems in a stormier world. Here we provide a systematic, standardized and quantitative approach for identifying critical processes shaping lake ecosystem resistance following extreme storms. We identified 576 extreme wind storms for eight lakes in Europe and North America. We calculated the resistance and resilience of each lake’s surface water temperature and oxygen saturation following each storm. Sharp decreases and increases in epilimnetic temperature and oxygen saturation caused by extreme storms resulted in unpredictable changes in lake resilience values across lakes, with a tendency not to return to pre-storm conditions. Resistance was primarily shaped by mean annual chlorophyll a concentration and its overall relationship with other physiochemical lake and storm characteristics. We modeled variation in resistance as a function of both lake and storm conditions, and the results suggested that eutrophic lakes were consistently less resistant to extreme storms when compared to oligotrophic lakes. The lakes tended to be most resistant towards extreme storms when antecedent surface waters were warm and oxygen saturated, but overall resistance was highest in lakes with low concentrations of mean annual chlorophyll a and total phosphorus. Our findings suggest physiochemical responses of lakes to meteorological forcing is shaped by ecological and/or physical feedbacks and processes that determine trophic state, such as the influence of differences in nutrient availability and algal growth.
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