TY  - JOUR
A1  - Weyhenmeyer, Gesa A.
A1  - Mackay, Murray
A1  - Stockwell, Jason D.
A1  - Thiery, Wim
A1  - Grossart, Hans-Peter
A1  - Augusto-Silva, Petala B.
A1  - Baulch, Helen M.
A1  - de Eyto, Elvira
A1  - Hejzlar, Josef
A1  - Kangur, Kuelli
A1  - Kirillin, Georgiy
A1  - Pierson, Don C.
A1  - Rusak, James A.
A1  - Sadro, Steven
A1  - Woolway, R. Iestyn
T1  - Citizen science shows systematic changes in the temperature difference between air and inland waters with global warming
JF  - Scientific reports
N2  - Citizen science projects have a long history in ecological studies. The research usefulness of such projects is dependent on applying simple and standardized methods. Here, we conducted a citizen science project that involved more than 3500 Swedish high school students to examine the temperature difference between surface water and the overlying air (T-w-T-a) as a proxy for sensible heat flux (Q(H)). If Q(H) is directed upward, corresponding to positive T-w-T-a, it can enhance CO2 and CH4 emissions from inland waters, thereby contributing to increased greenhouse gas concentrations in the atmosphere. The students found mostly negative T-w-T-a across small ponds, lakes, streams/rivers and the sea shore (i.e. downward Q(H)), with T-w-T-a becoming increasingly negative with increasing T-a. Further examination of T-w-T-a using high-frequency temperature data from inland waters across the globe confirmed that T-w-T-a is linearly related to T-a. Using the longest available high-frequency temperature time series from Lake Erken, Sweden, we found a rapid increase in the occasions of negative T-w-T-a with increasing annual mean T-a since 1989. From these results, we can expect that ongoing and projected global warming will result in increasingly negative T-w-T-a, thereby reducing CO2 and CH4 transfer velocities from inland waters into the atmosphere.
Y1  - 2017
U6  - https://doi.org/10.1038/srep43890
SN  - 2045-2322
VL  - 7
PB  - Nature Publ. Group
CY  - London
ER  - 
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  -