TY  - JOUR
A1  - Giling, Darren P.
A1  - Staehr, Peter A.
A1  - Grossart, Hans-Peter
A1  - Andersen, Mikkel Rene
A1  - Boehrer, Bertram
A1  - Escot, Carmelo
A1  - Evrendilek, Fatih
A1  - Gomez-Gener, Lluis
A1  - Honti, Mark
A1  - Jones, Ian D.
A1  - Karakaya, Nusret
A1  - Laas, Alo
A1  - Moreno-Ostos, Enrique
A1  - Rinke, Karsten
A1  - Scharfenberger, Ulrike
A1  - Schmidt, Silke R.
A1  - Weber, Michael
A1  - Woolway, R. Iestyn
A1  - Zwart, Jacob A.
A1  - Obrador, Biel
T1  - Delving deeper: Metabolic processes in the metalimnion of stratified lakes
JF  - Limnology and oceanography
N2  - Many lakes exhibit seasonal stratification, during which they develop strong thermal and chemical gradients. An expansion of depth-integrated monitoring programs has provided insight into the importance of organic carbon processing that occurs below the upper mixed layer. However, the chemical and physical drivers of metabolism and metabolic coupling remain unresolved, especially in the metalimnion. In this depth zone, sharp gradients in key resources such as light and temperature co-occur with dynamic physical conditions that influence metabolic processes directly and simultaneously hamper the accurate tracing of biological activity. We evaluated the drivers of metalimnetic metabolism and its associated uncertainty across 10 stratified lakes in Europe and North America. We hypothesized that the metalimnion would contribute highly to whole-lake functioning in clear oligotrophic lakes, and that metabolic rates would be highly variable in unstable polymictic lakes. Depth-integrated rates of gross primary production (GPP) and ecosystem respiration (ER) were modelled from diel dissolved oxygen curves using a Bayesian approach. Metabolic estimates were more uncertain below the epilimnion, but uncertainty was not consistently related to lake morphology or mixing regime. Metalimnetic rates exhibited high day-to-day variability in all trophic states, with the metalimnetic contribution to daily whole-lake GPP and ER ranging from 0% to 87% and < 1% to 92%, respectively. Nonetheless, the metalimnion of low-nutrient lakes contributed strongly to whole-lake metabolism on average, driven by a collinear combination of highlight, low surface-water phosphorous concentration and high metalimnetic volume. Consequently, a single-sensor approach does not necessarily reflect whole-ecosystem carbon dynamics in stratified lakes.
Y1  - 2017
U6  - https://doi.org/10.1002/lno.10504
SN  - 0024-3590
SN  - 1939-5590
VL  - 62
SP  - 1288
EP  - 1306
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Bertilsson, Stefan
A1  - Burgin, Amy
A1  - Carey, Cayelan C.
A1  - Fey, Samuel B.
A1  - Grossart, Hans-Peter
A1  - Grubisic, Lorena M.
A1  - Jones, Ian D.
A1  - Kirillin, Georgiy
A1  - Lennon, Jay T.
A1  - Shade, Ashley
A1  - Smyth, Robyn L.
T1  - The under-ice microbiome of seasonally frozen lakes
JF  - Limnology and oceanography
N2  - Compared to the well-studied open water of the "growing" season, under-ice conditions in lakes are characterized by low and rather constant temperature, slow water movements, limited light availability, and reduced exchange with the surrounding landscape. These conditions interact with ice-cover duration to shape microbial processes in temperate lakes and ultimately influence the phenology of community and ecosystem processes. We review the current knowledge on microorganisms in seasonally frozen lakes. Specifically, we highlight how under-ice conditions alter lake physics and the ways that this can affect the distribution and metabolism of auto-and heterotrophic microorganisms. We identify functional traits that we hypothesize are important for understanding under-ice dynamics and discuss how these traits influence species interactions. As ice coverage duration has already been seen to reduce as air temperatures have warmed, the dynamics of the under-ice microbiome are important for understanding and predicting the dynamics and functioning of seasonally frozen lakes in the near future.
Y1  - 2013
U6  - https://doi.org/10.4319/lo.2013.58.6.1998
SN  - 0024-3590
SN  - 1939-5590
VL  - 58
IS  - 6
SP  - 1998
EP  - 2012
PB  - Wiley
CY  - Waco
ER  -