Adaptive root foraging strategies along a boreal–temperate forest gradient

The tree root–mycorhizosphere plays a key role in resource uptake, but also in the adaptation of forests to changing environments. The adaptive foraging mechanisms of ectomycorrhizal (EcM) and fine roots of Picea abies, Pinus sylvestris and Betula pendula were evaluated along a gradient from temperate to subarctic boreal forest (38 sites between latitudes 48°N and 69°N) in Europe. Variables describing tree resource uptake structures and processes (absorptive fine root biomass and morphology, nitrogen (N) concentration in absorptive roots, extramatrical mycelium (EMM) biomass, community structure of root-associated EcM fungi, soil and rhizosphere bacteria) were used to analyse relationships between root system functional traits and climate, soil and stand characteristics. Absorptive fine root biomass per stand basal area increased significantly from temperate to boreal forests, coinciding with longer and thinner root tips with higher tissue density, smaller EMM biomass per root length and a shift in soil microbial community structure. The soil carbon (C) : N ratio was found to explain most of the variability in absorptive fine root and EMM biomass, root tissue density, N concentration and rhizosphere bacterial community structure. We suggest a concept of absorptive fine root foraging strategies involving both qualitative and quantitative changes in the root–mycorrhiza–bacteria continuum along climate and soil C : N gradients.Peer reviewe

Data Descriptor : A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins

Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment.Peer reviewe

Reconstruction of the microbial phosphorus turnover in forest soils with different phosphorus stocks.

The main objective of this study was the identification of microbial traits and key players involved in mobilization of phosphorus (P) in forest soils. In the mineral topsoil, the strongest genetic potential was proven for P transporters, the solubilization of inorganic-P and P starvation-inducible genes. The P cycle associated microbial community was highly complex, though dominated by few dominant taxa. While the impact of the soil P content on community composition was insignificant, an adaptation of the microbial P nutrition strategy to the soil specific P characteristics was proven

Rekonstruktion des mikrobiellen Phosphor-Umsatzes in Waldböden mit unterschiedlichen Phosphor-Gehalten

The main objective of this study was the identification of microbial traits and key players involved in mobilization of phosphorus (P) in forest soils. In the mineral topsoil, the strongest genetic potential was proven for P transporters, the solubilization of inorganic-P and P starvation-inducible genes. The P cycle associated microbial community was highly complex, though dominated by few dominant taxa. While the impact of the soil P content on community composition was insignificant, an adaptation of the microbial P nutrition strategy to the soil specific P characteristics was proven.Ziel dieser Arbeit war die Identifizierung mikrobieller Fähigkeiten und Hauptakteure der Mobilisierung von Phosphor (P) im Waldboden. Im mineralischen Oberboden wurde das größte genetische Potential für P Transporter, die Mobilisierung von anorganischem-P und durch P Mangel induzierbare Gene nachgewiesen. Die am P Kreislauf beteiligte mikrobielle Gemeinschaft war hochkomplex, obwohl dominiert von wenigen abundanten Taxa. Die Zusammensetzung der mikrobiellen Gemeinschaft wurde kaum vom P Gehalt des Bodens beeinflusst, während die P Ernährungsstrategie eine Anpassung zeigte