Premium
Where does the river end? Drivers of spatiotemporal variability in CO 2 concentration and flux in the inflow area of a large boreal lake
Author(s) -
Chmiel Hannah E.,
Hofmann Hilmar,
Sobek Sebastian,
Efremova Tatyana,
Pasche Natacha
Publication year - 2020
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.11378
Subject(s) - bay , environmental science , inflow , spatial variability , flux (metallurgy) , hydrology (agriculture) , discharge , boreal , atmosphere (unit) , estuary , carbon dioxide , oceanography , atmospheric sciences , drainage basin , geology , ecology , biology , geography , metallurgy , paleontology , statistics , materials science , mathematics , geotechnical engineering , cartography , physics , thermodynamics
River inflow affects the spatiotemporal variability of carbon dioxide (CO 2 ) in the water column of lakes and may locally influence CO 2 gas exchange with the atmosphere. However, spatiotemporal CO 2 variability at river inflow sites is often unknown leaving estimates of lake‐wide CO 2 emission uncertain. Here, we investigated the CO 2 concentration and flux variability along a river‐impacted bay and remote sampling locations of Lake Onego. During 3 years, we resolved spatial CO 2 gradients between river inflow and central lake and recorded the temporal course of CO 2 in the bay from the ice‐covered period to early summer. We found that the river had a major influence on the spatial CO 2 variability during ice‐covered periods and contributed ~ 35% to the total amount of CO 2 in the bay. The bay was a source of CO 2 to the atmosphere at ice‐melt each year emitting 2–15 times the amount as an equally sized area in the central lake. However, there was large interannual variability in the spring CO 2 emission from the bay related to differences in discharge and climate that affected the hydrodynamic development of the lake during spring. In early summer, the spatial CO 2 variability was unrelated to the river signal but correlated negatively with dissolved oxygen concentrations instead indicating a stronger biological control on CO 2 . Our study reveals a large variability of CO 2 and its drivers at river inflow sites at the seasonal and at the interannual time scale. Understanding these dynamics is essential for predicting lake‐wide CO 2 fluxes more accurately under a warming climate.