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Title: Methane and Primary Productivity in Lakes: Divergence of Temporal and Spatial Relationships
Abstract

In lakes, the production and emission of methane (CH4) have been linked to lake trophic status. However, few studies have quantified the temporal response of lake CH4dynamics to primary productivity at the ecosystem scale or considered how the response may vary across lakes. Here, we investigate relationships between lake CH4dynamics and ecosystem primary productivity across both space and time using data from five lakes in northern Wisconsin, USA. From 2014 to 2019, we estimated hypolimnetic CH4storage rates for each lake using timeseries of hypolimnetic CH4concentration through the summer season. Across all lakes and years, hypolimnetic CH4storage ranged from <0.001 to 7.6 mmol CH4 m−2 d−1and was positively related to the mean summer rate of gross primary productivity (GPP). However, within‐lake temporal responses to GPP diverged from the spatial relationship, and GPP was not a significant predictor of interannual variability in CH4storage at the lake scale. Using these data, we consider how and why temporal responses may differ from spatial patterns and demonstrate how extrapolating cross‐lake relationships for prediction at the lake scale may substantially overestimate the rate of change of CH4dynamics in response to lake primary productivity. We conclude that future predictions of lake‐mediated climate feedbacks in response to a shifting distribution of trophic status should incorporate both varying lake responses and the temporal scale of change.

 
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Award ID(s):
1754363 1754561
NSF-PAR ID:
10455534
Author(s) / Creator(s):
 ;  ;  ;  ;  
Publisher / Repository:
DOI PREFIX: 10.1029
Date Published:
Journal Name:
Journal of Geophysical Research: Biogeosciences
Volume:
125
Issue:
9
ISSN:
2169-8953
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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