TY  - JOUR
A1  - Sorkau, Elisabeth
A1  - Boch, Steffen
A1  - Boeddinghaus, Runa S.
A1  - Bonkowski, Michael
A1  - Fischer, Markus
A1  - Kandeler, Ellen
A1  - Klaus, Valentin H.
A1  - Kleinebecker, Till
A1  - Marhan, Sven
A1  - Müller, Jörg
A1  - Prati, Daniel
A1  - Schoening, Ingo
A1  - Schrumpf, Marion
A1  - Weinert, Jan
A1  - Oelmann, Yvonne
T1  - The role of soil chemical properties, land use and plant diversity for microbial phosphorus in forest and grassland soils
JF  - Journal of plant nutrition and soil science = Zeitschrift für Pflanzenernährung und Bodenkunde
N2  - Management intensity modifies soil properties, e.g., organic carbon (C-org) concentrations and soil pH with potential feedbacks on plant diversity. These changes might influence microbial P concentrations (P-mic) in soil representing an important component of the Pcycle. Our objectives were to elucidate whether abiotic and biotic variables controlling P-mic concentrations in soil are the same for forests and grasslands, and to assess the effect of region and management on P-mic concentrations in forest and grassland soils as mediated by the controlling variables. In three regions of Germany, Schwabische Alb, Hanich-Dun, and Schorfheide-Chorin, we studied forest and grassland plots (each n=150) differing in plant diversity and land-use intensity. In contrast to controls of microbial biomass carbon (C-mic), P-mic was strongly influenced by soil pH, which in turn affected phosphorus (P) availability and thus microbial Puptake in forest and grassland soils. Furthermore, P-mic concentrations in forest and grassland soils increased with increasing plant diversity. Using structural equation models, we could show that soil C-org is the profound driver of plant diversity effects on P-mic in grasslands. For both forest and grassland, we found regional differences in P-mic attributable to differing environmental conditions (pH, soil moisture). Forest management and tree species showed no effect on P-mic due to a lack of effects on controlling variables (e.g., C-org). We also did not find management effects in grassland soils which might be caused by either compensation of differently directed effects across sites or by legacy effects of former fertilization constraining the relevance of actual practices. We conclude that variables controlling P-mic or C-mic in soil differ in part and that regional differences in controlling variables are more important for P-mic in soil than those induced by management.
KW  - age class forest
KW  - land-use intensity
KW  - meadow
KW  - microbes
KW  - pasture
KW  - unmanaged forest
Y1  - 2018
U6  - https://doi.org/10.1002/jpln.201700082
SN  - 1436-8730
SN  - 1522-2624
VL  - 181
IS  - 2
SP  - 185
EP  - 197
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Heslop, J. K.
A1  - Winkel, Matthias
A1  - Anthony, K. M. Walter
A1  - Spencer, R. G. M.
A1  - Podgorski, D. C.
A1  - Zito, P.
A1  - Kholodov, A.
A1  - Zhang, M.
A1  - Liebner, Susanne
T1  - Increasing organic carbon biolability with depth in yedoma permafrost
BT  - ramifications for future climate change
JF  - Journal of geophysical research : Biogeosciences
N2  - Permafrost thaw subjects previously frozen organic carbon (OC) to microbial decomposition, generating the greenhouse gases (GHG) carbon dioxide (CO2) and methane (CH4) and fueling a positive climate feedback. Over one quarter of permafrost OC is stored in deep, ice-rich Pleistocene-aged yedoma permafrost deposits. We used a combination of anaerobic incubations, microbial sequencing, and ultrahigh-resolution mass spectrometry to show yedoma OC biolability increases with depth along a 12-m yedoma profile. In incubations at 3 degrees C and 13 degrees C, GHG production per unit OC at 12-versus 1.3-m depth was 4.6 and 20.5 times greater, respectively. Bacterial diversity decreased with depth and we detected methanogens at all our sampled depths, suggesting that in situ microbial communities are equipped to metabolize thawed OC into CH4. We concurrently observed an increase in the relative abundance of reduced, saturated OC compounds, which corresponded to high proportions of C mineralization and positively correlated with anaerobic GHG production potentials and higher proportions of OC being mineralized as CH4. Taking into account the higher global warming potential (GWP) of CH4 compared to CO2, thawed yedoma sediments in our study had 2 times higher GWP at 12-versus 9.0-m depth at 3 degrees C and 15 times higher GWP at 13 degrees C. Considering that yedoma is vulnerable to processes that thaw deep OC, our findings imply that it is important to account for this increasing GHG production and GWP with depth to better understand the disproportionate impact of yedoma on the magnitude of the permafrost carbon feedback.
KW  - permafrost
KW  - carbon
KW  - yedoma
KW  - Alaska
KW  - FT-ICR MS
KW  - microbes
Y1  - 2019
U6  - https://doi.org/10.1029/2018JG004712
SN  - 2169-8953
SN  - 2169-8961
VL  - 124
IS  - 7
SP  - 2021
EP  - 2038
PB  - American Geophysical Union
CY  - Washington
ER  -