Fungal Community Response to Long-Term Soil Warming With Potential Implications for Soil Carbon Dynamics

The direction and magnitude of climate warming effects on ecosystem processes such as carbon cycling remain uncertain. Soil fungi are central to these processes due to their roles as decomposers of soil organic matter, as mycorrhizal symbionts, and as determinants of plant diversity. Yet despite their importance to ecosystem functioning, we lack a clear understanding of the long-term response of soil fungal communities to warming. Toward this goal, we characterized soil fungal communities in two replicated soil warming experiments at the Harvard Forest (Petersham, Massachusetts, USA) which had experienced 5 degrees C above ambient soil temperatures for 5 and 20 yr at the time of sampling. We assessed fungal diversity and community composition by sequencing the ITS2 region of rDNA using Illumina technology, along with soil C concentrations and chemistry. Three main findings emerged: (1) long-, but not short-term warming resulted in compositional shifts in the soil fungal community, particularly in the saprotrophic and unknown components of the community; (2) soil C concentrations and the total C stored in the organic horizon declined in response to both short- (5 yr) and long-term (20 yr) warming; and (3) following long-term warming, shifts in fungal guild relative abundances were associated with substantial changes in soil organic matter chemistry, particularly the relative abundance of lignin. Taken together, our results suggest that shifts with warming in the relative abundance of fungal functional groups and dominant fungal taxa are related to observed losses in total soil C

Microbial carbon use efficiency: accounting for population, community, and ecosystem-scale controls over the fate of metabolized organic matter

Microbial carbon use efficiency (CUE) is a critical regulator of soil organic matter dynamics and terrestrial carbon fluxes, with strong implications for soil biogeochemistry models. While ecologists increasingly appreciate the importance of CUE, its core concepts remain ambiguous: terminology is inconsistent and confusing, methods capture variable temporal and spatial scales, and the significance of many fundamental drivers remains inconclusive. Here we outline the processes underlying microbial efficiency and propose a conceptual framework that structures the definition of CUE according to increasingly broad temporal and spatial drivers where (1) CUEP reflects population-scale carbon use efficiency of microbes governed by species-specific metabolic and thermodynamic constraints, (2) CUEC defines community-scale microbial efficiency as gross biomass production per unit substrate taken up over short time scales, largely excluding recycling of microbial necromass and exudates, and (3) CUEE reflects the ecosystem-scale efficiency of net microbial biomass production (growth) per unit substrate taken up as iterative breakdown and recycling of microbial products occurs. CUEE integrates all internal and extracellular constraints on CUE and hence embodies an ecosystem perspective that fully captures all drivers of microbial biomass synthesis and decay. These three definitions are distinct yet complementary, capturing the capacity for carbon storage in microbial biomass across different ecological scales. By unifying the existing concepts and terminology underlying microbial efficiency, our framework enhances data interpretation and theoretical advances

Deployment of a large-scale soil monitoring geosensor network

We provide an overview of our practical experience with developing a distributed sensor network to monitor soil response to climate change and increase our understanding of the complex interactions of the surrounding ecological, biogeochemical and meteorological processes. The network consists of seven sites with unique topographical, and land-use characteristics, spread across a large area in the state of New Hampshire (US). The system was designed to measure soil moisture, soil CO2 efflux and make other ancillary measurements (air temperature, precipitation, wind speed etc.). The system design encompasses sensor and hardware selection, customization and the overcoming design constraints such as the need to operate a power hungry sensing system at remote locations with access only to solar power. The data we collect streams to the web as an outreach and teaching resource, provides input to ecosystem models used to predict how ecosystems in the region will respond to climate and land-use change, and directly monitors soil properties and processes in a changing climate

Deployment of a Large-Scale Soil Moisture Geosensor Network- Experience and Lessons Learnt

We provide an overview of our practical experience with developing a distributed sensor network to monitor soil response to climate change and increase our understanding of the complex interactions of the surrounding ecological, biogeochemical and meteorological processes. The network consists of seven sites with unique topographical, and land-use characteristics, spread across a large area in the state of New Hampshire (US). The system was designed to measure soil moisture, soil CO2 efflux and make other ancillary measurements (air temperature, precipitation, wind speed etc.). The system design encompasses sensor and hardware selection, customization and the overcoming design constraints such as the need to operate a power hungry sensing system at remote locations with access only to solar power. The data we collect streams to the web as an outreach and teaching resource, provides input to ecosystem models used to predict how ecosystems in the region will respond to climate and land-use change, and directly monitors soil properties and processes in a changing climate

Deployment of a large-scale soil monitoring geosensor network

We provide an overview of our practical experience with developing a distributed sensor network to monitor soil response to climate change and increase our understanding of the complex interactions of the surrounding ecological, biogeochemical and meteorological processes. The network consists of seven sites with unique topographical, and land-use characteristics, spread across a large area in the state of New Hampshire (US). The system was designed to measure soil moisture, soil CO2 efflux and make other ancillary measurements (air temperature, precipitation, wind speed etc.). The system design encompasses sensor and hardware selection, customization and the overcoming design constraints such as the need to operate a power hungry sensing system at remote locations with access only to solar power. The data we collect streams to the web as an outreach and teaching resource, provides input to ecosystem models used to predict how ecosystems in the region will respond to climate and land-use change, and directly monitors soil properties and processes in a changing climate

Split-footed lacewings declined over time: indications from the morphological diversity of their antlion-like larvae

<jats:title>Abstract</jats:title><jats:p>Nymphidae, the group of split-footed lacewings, is a rather species-poor group. Split-footed lacewings nowadays are restricted to Australasia, while fossil forms are also known from other areas of the world, indicating that the group was more species-rich and therefore likely diverse in the past. Split-footed lacewings have rather distinct larvae, roughly resembling antlion larvae, but differing from the latter especially with regard to the mandibles. Antlion larvae usually have three prominent teeth on each mandible, while at least extant larvae of split-footed lacewings only have a single prominent tooth per mandible. Fossils interpreted as larvae of split-footed lacewings are well known from amber from Myanmar (ca. 100 myr; Burmese amber) and by a single specimen from Baltic amber (about 40 myr). We here report additional fossil specimens from Myanmar amber, expanding the known record of fossil forms from six depicted specimens to 15. For the extant fauna, we could compile 25 larvae. We compare the diversity of shape of extant and fossil larvae through time using an outline analysis (based on elliptic Fourier transformation) of the head. The results of this analysis indicate that the morphological diversity, or disparity, of split-footed lacewing larvae was higher in the past than it is today. With this type of analysis, we can show a loss of diversity over time, without the necessity to identify the fossil larvae down to a narrow taxonomical range. A similar pattern has already been recognised in silky lacewings, Psychopsidae. This might indicate a general loss of diversity of lacewing larvae.</jats:p&gt