Dead Biomass Research Articles

Millipedes (Diplopoda) of the Ojców National Park (Poland)

The Ojców National Park (southern Poland) is a small limestone area with outstanding natural values. Until now, there was a lack of information on the spatial distribution of species, their preference of biotopes and microhabitats in the area under study. An interesting question is also the occurrence of native species and the penetration of alien species. Biodiversity can be threatened in such a small, heavily visited by tourists and predominantly forested area, isolated from a similar landscape by agrocenoses and further eroded below the level of the surrounding landscape. Millipedes are soil arthropods, sensitive to calcified soils, stand structure, composition and availability of dead plant biomass, and microclimatic conditions. They are therefore an important reference group of animals for the management of the Ojców NP. In the spring of 2002 and autumn 2004, we carried out detailed inventory research of Diplopoda in the most typical habitats there. We recorded 19 taxa, 2 of which could not be determined to the species level. Together with literature data, a total of 23 species (ca 25% of Polish millipede fauna) are listed here. The occurrence of the moisture-preferring Carpathian mountain species Polydesmus tatranus Latzel, 1882 deserves attention. As important species, bound to preserved deciduous and mixed forests with plenty of dead wood, we consider Glomeris pustulata (Fabricius, 1781) and Nemasoma varicorne C. L. Koch, 1847. The retreat of rare native species as well as invasive aliene species were not recorded. The issue of the unclear nomenclature of the representatives of the genus Trachysphaera (Gervaisia) Heller, 1858 occurring in this area and accumulated throughout history is addressed.

Determining optimal forest rotation ages and carbon offset credits: Accounting for post‐harvest carbon storehouses

AbstractSequestering carbon in forest ecosystems is important for mitigating climate change. A major policy concern is whether forests should be left unharvested to avoid carbon dioxide (CO2) emissions and store carbon, or harvested to take advantage of potential carbon storage in post‐harvest wood product sinks and removal of CO2 from the atmosphere by new growth. The issue is addressed in this paper by examining carbon rotation ages that consider commercial timber as well as carbon values. A discrete‐time optimal rotation age model is developed that employs data on carbon fluxes stored in both living and dead biomass as opposed to carbon as a function of timber growth. Carbon is allocated to several ecosystem and post‐harvest product pools that decay over time at different rates. In addition, the timing of carbon fluxes is taken into account by weighting future carbon fluxes as less important than current ones. Using simple formulae for determining optimal rotation ages, we find that: (1) Reducing the price of timber while increasing the price of carbon will increase rotation age, perhaps to infinity (stand remains unharvested). (2) An increase in the rate used to discount physical carbon generally reduces the rotation age, but not in all cases. (3) As a corollary, an increase in the price of carbon increases or reduces rotation age depending on the weight chosen to discount future carbon fluxes. (4) Site characteristics and the mix of species on the site affect conclusions (2) and (3). (5) A large variety of carbon offset credits from forestry activities could be justified, which makes it difficult to accept any.

Sustainable development and management of beech forests

Beech is a very widespread species on the entire Eurasian continent. It grows and develops in different ecological and habitat conditions in a wide horizontal and vertical amplitude. It can be found at altitudes below 100 and above 2,000 m. Beech forests develop in different age stands from young to very old (old-growth forests). They can be pure or mixed with other species or they can be very different in origin (generative or vegetative). They develop as eaven-aged or uneaven-aged stands, and some of the beech forests have the characteristics of forests with high natural values and are very important for the conservation of biodiversity. Their natural regeneration process is of essential importance for the survival and sustainable development of beech forests. Restoration of beech forests can be achieved naturally or artificially. In modern forestry science and practice, natural forest regeneration is always preferred. The processes of natural regeneration have different development depending on whether they take place under the protection of the parent stand or take place in an open canopy in the forest or on uncultivated terrain. The density of the canopy has a great influence, so that with the increase of the canopy of the parent stand during the natural renewal, there is a decrease in the number of regeneration individuals(offsprings) in all developmental stages. During the natural regeneration in different conditions of the stand canopy and the size of the openings within the forest, the most abundant and best regeneration is observed in the openings up to 500 m², then for openings within 500 and 1,000 m², and least in openings between 1,000 and 1,500 m². This clearly indicates that large openings within the forest are not suitable for the natural regeneration of beech because the number of offsprings, which are very necessary in the younger developmental stages, is continuously decreasing. The natural renewal that develops in the conditions of circular openings within the size of up to 500 m² has the best quality structure of the offspring. In such openings, about 60% of the offspring is of good quality, about 25% is of medium quality and about 15% is of poor quality. In openings between 500 and 1,000 m2 , the number of good quality natural regeneration is reduced to 41%, the number of medium quality natural regeneration is increased to 38% and from poor quality to 21%. The quality structure of natural regeneration is further reduced in openings between 1,000 and 1,500 m² where only about 20% of the offsprings is of good quality, about 30% is of medium quality and about 50% is ofpoor quality. With openings larger than 500 m², weeds are very common. Beech stands in different habitats have large differences in their productivity, caused by the wide range of the beech forests in different habitat conditions and in different cultivation forms. Aboveground biomass in beech forests varies depending on the age of the forest, the way it is managed and used, as well as numerous environmental factors. High values of aboveground biomass in preserved oldgrowth beech forests above 750 t·ha-1 are known. Moderate values in commercial forests range between 200 and 400 t·ha-1 . In dominant trees, the largest biomass is found in tree crowns, while in subdominant and suppressed trees, the largest biomass is in the trunk, which is the result of a smaller crown due to the lack of solar radiation. Generally, 1/3 or slightly less of the aboveground biomass comes from the branches, the leaves cover about 1-2%, while the largest biomass (60- 70%) is concentrated in the tree. Dead biomass in beech forests consists of dead biomass accumulated in the forest floor, as well as in standing and lying dead biomass. Forest biomass varies in European beech forests: beech forests in the north show less biomass of 3-12 t·ha-1 , while high values (25-75 t·ha-1 ) are registered for the southeastern parts. Standing dead biomass in forests amounts to 1.2-6.0% of living aboveground biomass or 2-5 t·ha-1 . Lying dead biomass in European beech forests varies to a very large extent depending on the conservation of beech forests and their developmental stage. The European range is 32-310 m3 ∙ha-1 , and values above 130 m3 ∙ha-1 belong to the preserved beech forest reserves. When choosing methods of beech forest management, one should always take into account the biological characteristics of beech in relation to the ecological conditions in the area where beech develops. Today, various and professionally supported methods of forest management with the aim of their sustainable development demand great importance for beech forests.

Less fuel for the next fire? Short-interval fire delays forest recovery and interacting drivers amplify effects.

As 21st-century climate and disturbance dynamics depart from historic baselines, ecosystem resilience is uncertain. Multiple drivers are changing simultaneously, and interactions among drivers could amplify ecosystem vulnerability to change. Subalpine forests in Greater Yellowstone (Northern Rocky Mountains, USA) were historically resilient to infrequent (100-300 year), severe fire. We sampled paired short-interval (<30-year) and long-interval (>125-year) post-fire plots most recently burned between 1988 and 2018 to address two questions: (1) How do short-interval fire, climate, topography, and distance to unburned live forest edge interact to affect post-fire forest regeneration? (2) How do forest biomass and fuels vary following short-interval versus long-interval severe fires? Mean post-fire live tree stem density was an order of magnitude lower following short-interval versus long-interval fires (3240 vs. 28,741 stems ha-1 , respectively). Differences between paired plots were amplified at longer distances to live forest edge. Surprisingly, warmer-drier climate was associated with higher seedling densities even after short-interval fire, likely relating to regional variation in serotiny of lodgepole pine (Pinus contorta var. latifolia). Unlike conifers, density of aspen (Populus tremuloides), a deciduous resprouter, increased with short-interval versus long-interval fires (mean 384 vs. 62 stems ha-1 , respectively). Live biomass and canopy fuels remained low nearly 30 years after short-interval fire, in contrast with rapid recovery after long-interval fire, suggesting that future burn severity may be reduced for several decades following reburns. Short-interval plots also had half as much dead woody biomass compared with long-interval plots (60 vs. 121 Mg ha-1 ), primarily due to the absence of large snags. Our results suggest differences in tree regeneration following short-interval versus long-interval fires will be especially pronounced where serotiny was high historically. Propagule limitation will also interact with short-interval fires to diminish tree regeneration but lessen subsequent burn severity. Amplifying driver interactions are likely to threaten forest resilience under expected trajectories of a future fire.

Litter accumulation, not light limitation, drives early plant recruitment

Abstract Theory predicts a decline in grassland diversity under nutrient enrichment and loss of herbivory, and one possible cause is hampered seedling recruitment. Two potential drivers for reduced diversity at the seedling level are diminished light availability caused by surrounding vegetation and accumulation of dead biomass. To test the importance of these two mechanisms on early recruitment, we added seeds of 15 herbaceous grassland plant species and monitored sown and natural seedling emergence during one growing season in a full factorial field experiment with light addition and litter removal under fertilization and exclusion of mammalian herbivores in an experimental grassland in Central Germany. We used modern LED lamps, mimicking the spectrum of natural sun light, to provide light to small‐statured understorey plants. This novel experimental set‐up allowed us to specifically disentangle the roles of light limitation and litter accumulation independently and in combination. In general, herbivore exclusion, but not fertilization increased the amount of litter biomass. Litter removal increased seedling number and richness by 83% and 33%, respectively, while light addition had no significant main effect on seedling recruitment, nor did it interact with any other factors, and did not affect recruitment even when litter was removed. In addition, fertilization had a negative and herbivore exclusion a negligible impact on recruitment, and these effects were independent of litter removal. Furthermore, seedling number and richness were unrelated to light intensity and quality, litter depth, soil moisture, temperature and C:N ratio. Synthesis: These results provide novel insights into the role of light limitation versus litter accumulation driving early recruitment and help understanding the mechanisms that affect diversity in grassland communities via recruitment. Our results highlight the detrimental role of litter accumulation as opposed to surrounding vegetation induced light deficiency driving early recruitment from seeds and call for management actions that reduce the amount of litter when maintaining or restoring diversity.

Annual biomass spatial data for southern California (2001-2021): Above- and belowground, standing dead, and litter.

Biomass estimates for shrub-dominated ecosystems in southern California have been generated at national and statewide extents. However, existing data tend to underestimate biomass in shrub vegetation types, are limited to one point in time, or estimate aboveground live biomass only. In this study, we extended our previously developed estimates of aboveground live biomass (AGLBM) based on the empirical relationship of plot-based field biomass measurements to Landsat NDVI and multiple environmental factors to include other vegetative pools of biomass. AGLBM estimates were made by extracting plot values from elevation, solar radiation, aspect, slope, soil type, landform, climatic water deficit, evapotranspiration, and precipitation rasters and then using a Random Forest model to estimate per-pixel AGLBM across our southern California study area. By substituting year-specific Landsat NDVI and precipitation data, we created a stack of annual above ground live biomass raster layers for each year from 2001 - 2021. Using these AGLBM data as a foundation, we developed decision rules to estimate belowground, standing dead, and litter biomass pools. These rules were based on relationships between AGLBM and the biomass of the other vegetative pools derived primarily from peer reviewed literature and an existing spatial dataset. For shrub vegetation types (our primary focus), rules were based on literature estimates by the post-fire regeneration strategy of each species (obligate seeder, facultative seeder, obligate resprouter). Similarly, for non-shrub vegetation types (grasslands, woodlands) we used literature and existing spatial datasets specific to each vegetation type to define rules to estimate the other pools from AGLBM. Using a Python language script that accessed ESRI raster GIS utilities, we applied decision rules to create raster layers for each of the non-AGLBM pools for the years 2001-2021. The resulting spatial data archive contains a zipped file for each year; each of these files contains four 32-bit tiff files for each of the four biomass pools (AGLBM, standing dead, litter, and below ground). The biomass units are g/m2 . We estimated the uncertainty of our biomass data by conducting a Monte Carlo analysis of the inputs used to generate the data. Our Monte Carlo technique used randomly generated values for each of the literature-based and spatial inputs based on their expected distribution. We conducted 200 Monte Carlo iterations, which produced percent uncertainty values for each of the biomass pools. Results showed, using 2010 as an example, mean biomass for the study area and percent uncertainty for each of the pools as: AGLBM (905.4 g/m2 , 14.4%); standing dead (644.9 g/m2 , 1.3 %); litter (731.2 g/m2 , 1.2 %); and belowground (776.2 g/m2 , 17.2 %). Because our methods are consistently applied across each year, the data produced can be used to inform changes in biomass pools due to disturbance and subsequent recovery. As such, these data provide an important contribution to supporting the management of shrub-dominated ecosystems for monitoring trends in carbon storage and assessing the impacts of wildfire and management activities, such as fuel management and restoration. There are no copyright restrictions on the data set; please cite this paper and the data package when using these data. This article is protected by copyright. All rights reserved.

Precipitation of High Mg-Calcite and Protodolomite Using Dead Biomass of Aerobic Halophilic Bacteria

Precipitation of High Mg-Calcite and Protodolomite Using Dead Biomass of Aerobic Halophilic Bacteria

Kinetic modeling and isotherm approach for biosorptive removal of hexavalent chromium using heat inactivated fungal biomass

AbstractTwo highly Cr (VI) resistant fungal strains, CSF‐1 and CSF‐2, were isolated and identified as Cladosporium sp. and Penicillium sp., respectively, using 18S rRNA gene sequencing. At optimized growth conditions, the dead biomass of Cladosporium sp. and Penicillium sp. has removed more than 99% of the supplemented Cr(VI). The kinetic study outcomes evidenced that the present fungal Cr(VI) biosorption is best fitting with the pseudo‐first‐order model with higher R2 values (i.e., 0.70–0.95) than that of the pseudo‐second‐order kinetic model (R2 = 0.02–0.73). After analyzing the R2 values, it was observed that the Langmuir and Freundlich isotherm models best fit the Cr(VI) biosorption employing fungal biomass.

Potential application of Curtobacterium sp. GX_31 for efficient biosorption of Cadmium: Isotherm and kinetic evaluation

In this study, the adsorption capacity and mechanism of Cd2+ by both live and dead Curtobacterium sp. GX_31 biomasses were evaluated using a batch experiment, adsorption isotherm and kinetic models, scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) analysis. The optimal pH, dosage, and contact time were 6.0, 1.0 g/L, and 60 min, respectively. Under optimal conditions, the removal efficiency was >90% for the live biomass and close to 100% for the dead biomass at an initial Cd2+ concentration of ≤10 mg/L, and the maximum adsorption capacities were 37.04 and 40.16 mg/g for the live and dead biosorbents with 200 mg/L Cd2+. The R2 values of the isotherm models indicated that the Temkin isotherm model was best fitted for both the live and dead biomass. The parameters KL (0.3998 vs. 5.1066), n (4.0177 vs. 6.0205), and bT (507.7947 vs. 675.3512) implied that the dead cells had a higher affinity, stronger adsorption, and higher binding energy than the live cells. The kinetic study showed that the pseudo-second-order model was more suitable for depicting the biosorption process, demonstrating that the rate-limiting step might be chemisorption and more than one step, which was confirmed by the intra-particle diffusion model. SEM analysis identified Cd2+ adsorbed onto the cell surface. FT-IR spectra suggested that hydroxyl, amino, carboxyl, sulphate and carbonyl functional groups might be involved in Cd2+ adsorption. Based on the results obtained, Curtobacterium sp. GX_31 might be a promising novel biosorbent for Cd2+-contaminated soil or water, especially at lower concentrations.

Strict forest protection: A meaningful contribution to Climate-Smart Forestry? An evaluation of temporal trends in the carbon balance of unmanaged forests in Germany

The role of unmanaged forests is discussed controversially in the context of climate change. One of the key questions is, whether they can contribute to the mitigation of climate change as a carbon sink and storage. However, carbon dynamics of forests after the cessation of management are not well understood. We analyzed a set of 64 forest sites, covering wide gradients of time since abandonment (0–68 years) and stand age (65–261 years) in even-aged, unmanaged beech forests. Five sites that were unmanaged for &amp;gt;100 years complemented the main dataset. We compiled site-specific carbon balances, distinguishing six carbon-compartments: Carbon in aboveground living and dead biomass, carbon in belowground living and dead biomass, and carbon in the organic layer and the mineral topsoil (0–30 cm). We found positive effects of increasing TSA on the carbon stock in living biomass and aboveground dead biomass for up to 50 years after management ceased. The average increase of the total carbon stock over 50 years of TSA was ≈ 80 Mg C ha–1. The effect of stand age on aboveground living biomass showed a convex relation. Aboveground dead biomass increased logistically with TSA, while belowground dead biomass decreased. On average, the five sites unmanaged for &amp;gt;100 years held lower total carbon stocks compared to the observed biomass peak around 50 years of TSA. However, they contained considerably higher amounts of deadwood. Carbon in the mineral soil did neither change with TSA nor with stand age and was driven by pH. Carbon stocks in newly unmanaged forests increased almost linearly for approximately 50 years after cessation of management. Subsequently, a stabilization or medium-term decrease in carbon stock was observed, likely due to the initiating transition from even-aged to multi-aged structures. We conclude that, besides their value for biodiversity and ecosystem functions, the potential of naturally developing forests as a medium-term carbon sink and long-term stable carbon storage should be considered as a valuable contribution to Climate-Smart Forestry.

Aquatic Bacteria Rheinheimera tangshanensis New Ability for Mercury Pollution Removal.

To explore the strong tolerance of bacteria to Hg pollution, aquatic Rheinheimera tangshanensis (RTS-4) was separated from industrial sewage, with a maximum Hg(II) tolerant concentration of 120 mg/L and a maximum Hg(II) removal rate of 86.72 ± 2.11%, in 48 h under optimum culture conditions. The Hg(II) bioremediation mechanisms of RTS-4 bacteria are as follows: (1) the reduction of Hg(II) through Hg reductase encoded by the mer operon; (2) the adsorption of Hg(II) through the production of extracellular polymeric substances (EPSs); and (3) the adsorption of Hg(II) using dead bacterial biomass (DBB). At low concentrations [Hg(II) ≤ 10 mg/L], RTS-4 bacteria employed Hg(II) reduction and DBB adsorption to remove Hg(II), and the removal percentages were 54.57 ± 0.36% and 45.43 ± 0.19% of the total removal efficiency, respectively. At moderate concentrations [10 mg/L < Hg(II) ≤ 50 mg/L], all three mechanisms listed above coexisted, with the percentages being 0.26 ± 0.01%, 81.70 ± 2.31%, and 18.04 ± 0.62% of the total removal rate, respectively. At high concentrations [Hg(II) > 50 mg/L], the bacteria primary employed EPS and DBB adsorption to remove Hg(II), where the percentages were 19.09 ± 0.04% and 80.91 ± 2.41% of the total removal rate, respectively. When all three mechanisms coexisted, the reduction of Hg(II) occurred within 8 h, the adsorption of Hg(II) by EPSs and DBB occurred within 8-20 h and after 20 h, respectively. This study provides an efficient and unused bacterium for the biological treatment of Hg pollution.

Resolving the fate of trace metals during microbial remineralization of phytoplankton biomass in precursor banded iron formation sediments

Banded Iron Formations (BIFs) have long been considered a sedimentary record of seawater trace metal composition during the Precambrian. However, recent work has suggested that much of the trace metal composition of BIFs could have been derived from phytoplankton biomass, not seawater. In this model, phytoplankton biomass settles from the photic zone to the seafloor sediments, where it is then oxidized by heterotrophic microbes, such as dissimilatory Fe(III) reducing (DIR) bacteria, for energy generation. Remineralization of this biomass released the trace metals associated with organic molecules from phytoplankton (i.e., in metalloproteins), allowing these metals to be captured by Fe oxyhydroxides and preserved in BIFs. While there is compelling evidence that the phytoplankton biomass served as a trace metal shuttle to precursor BIF sediments, it is unclear whether the degradation of biomass by DIR bacteria would liberate the biogenic trace metals as the model proposes. This work tests this hypothesis by using anoxic incubations of a model DIR bacterium (Shewanella oneidensis MR-1) with phytoplankton biomass as energy and carbon sources and ferrihydrite, a poorly crystalline Fe(III) oxyhydroxide (Fe(OH)3), as electron acceptor. Our results show that while S. oneidensis MR-1 can consume some of the carbon substrates found in phytoplankton biomass, there is no evidence that S. oneidensis MR-1 degraded metalloproteins which would have liberated trace metals. In the context of the Precambrian, these data imply that other heterotrophic bacteria, such as fermenters, may have had a larger role in the liberation of trace metals from dead biomass during early BIF development.

Las causas de los incendios de principios del año 2022 en la provincia de Corrientes

Fire is a natural grassland management tool, often used to eliminate the standing dead biomass and promote growth before the growing season. However, while there is a lack of data on the seasonal use of fire in the province of Corrientes, natural and induced fires in early 2022 affected over 10000 km2 at the peak of the growing season. This paper quantifies the extent of the fire-affected area in Corrientes during January and February 2022 and analyzes the contribution of natural and anthropogenic factors to the extent of the fire-affected area. We used the Google Earth Engine platform to identify and classify burnt areas using Sentinel satellite images, and applied simple and multiple regression analysis to investigate the contribution of natural and anthropogenic factors to the extent of the fire-affected area. Results show that 12% of Corrientes was affected by fire during the study period, with wetlands being the most affected land cover type. This study provides evidence of the relationship between natural and anthropogenic factors and the fires that affected Corrientes at the beginning of 2022. The results show that the reduction of water area and protected areas was positively and directly related to the extent of burnt areas, while the road network and livestock density were inversely and negatively related to the burned area size. Predicting fire patterns is essential to develop management policies to prevent or reduce the impact of future catastrophic events.

Carbon stocks and sequestration rate in mangroves and its major influencing factors from highly urbanised port city, southern India

This study estimated the total ecosystem carbon stock (TECS) and sediment carbon sequestration rate through burial for fragmented mangrove habitats of Kochi, south-west coast of India. The mean TECS of Kochi mangroves was estimated at 335.33 ± 184.47 t C ha−1, with above ground biomass of 171.68 ± 104.42 t C ha−1, belowground biomass of 83.30 ± 41.98 t C ha−1, litterfall carbon as dead biomass of 7.12 ± 2.81 t C ha−1 and soil carbon stock of 73.22 ± 39.40 t C ha−1. The average historical soil carbon sequestration rate of Kochi mangroves was also estimated as 2.95 t C ha−1 yr−1. The study revealed that there was significant variability in TECS and sediment carbon burial rate among riverine, estuarine and marine mangrove habitats and it appears that, the biological factors especially mangrove plant structure, species, age, litterfall production, crab density, mangrove conversion to aquaculture ponds and other urban pressure played major roles in driving the variability in carbon stocks and storage. While the sediment particle size, bulk density and the environmental settings played a secondary role. Very low TECS and soil carbon sequestration rate was found in aquaculture converted mangrove habitat. The CO2e of ecosystem carbon stock (496311.20 t CO2 e) and soil CO2 burial (10.62 t CO2 e ha−1 yr−1 respectively) of mangroves of Kochi, revealed that even with high urban pressure and anthropogenic activities which resulted in fragmented distribution, they are still potent in long term carbon sequestration unless it is not further disturbed. Therefore, conservation and restoration of mangrove habitats based on understanding of the regional controlling factors of carbon stock and carbon burial is a need for scientific climate change mitigation efforts. The study will also contribute to fill the gaps in global mangrove carbon stock assessments for avoiding uncertainties.

Assessing multiple limiting factors of seasonal biomass production and N content in a grassland with a year-round production.

There is little evidence on the extent that multiple factors simultaneously limit ecosystem function of grasslands with year-round production. Here we test if multiple factors simultaneously limit (i.e., more than one factor at a time) grassland functioning in different seasons and how they interacted with N availability. In a Flooding Pampa grassland, we ran a separate factorial experiment in spring, summer, and winter with several treatments: control, mowing, shading, P addition, watering (only in summer), and warming (only in winter), each of them crossed with two nitrogen treatments: control and N addition. Grassland functioning was assessed by aboveground net primary productivity (ANPP), green and standing dead biomass, and N content at the species group level. Out of 24 potential cases (three seasons by eight response variables), 13 corresponded to just one limiting factor, 4 to multiple limiting factors, and the other 7 to no evidence of limitation. In conclusion, grassland functioning in each season was most often limited by just one factor, while multiple limiting factors were rarer. Nitrogen was the prevailing limiting factor. Our study expands our knowledge of limitations imposed by factors associated with disturbance and stress, such as mowing, shading, water availability, and warming in grasslands with year-round production.

Ecological effects of mosquito control with Bti: evidence for shifts in the trophic structure of soil- and ground-based food webs

The microbial control agent Bacillus thuringiensis var. israelensis (Bti) has been successfully used worldwide to reduce abundances of biting Nematocera (Diptera), often with little direct impact on non-target organisms observed. However, the potential for additional indirect effects on other ecosystem properties, including on trophic linkages within food webs, is poorly known. We investigated the effects of multiple-year mosquito control treatments using the Bti product VectoBac®-G on the stable isotope composition of epigeal and soil-based consumers inhabiting replicate floodplains along the River Dalälven, Sweden. We observed significant changes in the isotopic composition of detritivores feeding at the base of floodplain food webs. Enchytraeid worms were characterised by 3.5% higher δ13C values in treated floodplains, suggesting increased consumption of δ13C-enriched food. The overall range of community-wide δ15N values was 56% greater in the treated floodplains, whilst δ15N values of oribatid mites were elevated by 97%. These results suggest extra fractionation in the transfer of nitrogen through floodplain food chains. We conjecture that the ecological mechanisms driving these food web shifts are (1) the mass mortality of high δ13C A. sticticus larvae, which leaves high concentrations of dead mosquito biomass deposited on soils at local scales, after the floodwaters have receded and (2) incorporation of the very high δ13C-enriched corn particles comprising the bulk of the VectoBac®-G product into floodplain food webs. Our results suggest that repeated applications of Bti might have wider, still largely unknown implications for nutrient and energy cycles within floodplain ecosystems.

An immobilized biosorbent from Paenibacillus dendritiformis dead cells and polyethersulfone for the sustainable bioremediation of lead from wastewater

Heavy metals, including lead, cause serious damage to human health and the surrounding environment. Natural biosorbents arise as environmentally friendly alternatives. In this study, two of the 41 isolates (8EF and 17OS) were the most efficient bacteria for growing on media supplemented with Pb2+ (1000 mg/L). At high concentrations up to 2000 mg/L, the pioneer isolate 17OS exhibited remarkable resistance to multiheavy metals. This isolate was identified as Paenibacillus dendritiformis 17OS and deposited in GenBank under accession number ON705726.1. Design-Expert was used to optimize Pb2+ metal removal by the tested bacteria. Results indicated that four of six variables were selected using a minimum-run resolution IV experimental design, with a significant affecting Pb2+ removal. Temperature and Pb2+ concentration were significant positive influences, whereas incubation period and agitation speed were significant negative ones. The tested strain modulated the four significant variables for maximum Pb2+ removal using Box–Behnken design. The sequential optimization method was beneficial in increasing biosorption by 4.29%. Dead biomass of P. dendritiformis 17OS was embedded with polyethersulfone to get a hydrophilic adsorptive membrane that can separate Pb2+ easily from aqueous solutions. SEM images and FT-IR analysis proved that the new biosorbent possesses a great structure and a lot of surface functional groups with a negative surface charge of − 9.1 mV. The removal rate of 200 mg/L Pb2+ from water reached 98% using 1.5 g/L of the immobilized biosorbent. The adsorption isotherm studies were displayed to determine the nature of the reaction. The adsorption process was related to Freundlich isotherm which describes the multilayer and heterogeneous adsorption of molecules to the adsorbent surface. In conclusion, dead bacterial cells were immobilized on a polyether sulfone giving it the characteristics of a novel adsorptive membrane for the bioremediation of lead from wastewater. Thus this study proposed a new generation of adsorptive membranes based on polyethersulfone and dead bacterial cells.

Fire Hazard: Undesirable Ecosystem Function of Orchard Vegetation

Fires will become an increasingly frequent perturbation even under the conditions of the mild climate zone and will interfere with the agricultural landscape. Fire is a natural phenomenon, and depending on ecosystems, vegetation may develop and contribute to the occurrence and spread of fire. Vegetation of the sour cherry orchard located in the climatically dry conditions of the South Moravian Region, Czech Republic (CR), was evaluated. Vegetation assessment was performed using phytocenological relevé. In each variant, 10 relevé were recorded. Coverage of the found species was estimated directly in percentages. Moreover, the maximum height in the stand was measured for each type of plant. Biomass of individual plant species was calculated, using the biomass index (IB) equation. The IB values of individual plant species in the treatments were processed by employing a multidimensional analysis of the ecological data. Different vegetation management practices in an orchard change the species diversity of the vegetation and thus the fire hazards in the orchard conditions. Grassy interrow has the most grass biomass during the entire vegetation season, and therefore represents the greatest hazard and spread of fire. The most important grasses include Arrhenatherum elatius, Dactylis glomerata, Festuca pratensis, Lolium perenne, and Poa pratensis. On the contrary, bare soil conditions in the interrow are most suitable for annual species, and this is the place with the highest changes in the number of species during the growing season. Biomass of the orchard vegetation combined with dry and warm weather increases the fire hazard. Annual and perennial grasses have very good potential for the production of biomass, which increases the hazard of fire. The nature of the vegetation in the orchards has the potential for the actual start of a fire and its subsequent spread, however, under other environmental conditions. During hot and dry weather, dead biomass may accumulate resulting in increasing the hazard of large wildfires. Varied orchard management practices lead to a higher diversity of vegetation and make orchards, islands of biodiversity in the agricultural landscape.

Classifying, inventorying, and mapping mature and old-growth forests in the United States

Because of its importance to both carbon storage and biodiversity, old forest has regained currency as a focus of forest management and policy. However, absence of a systematic approach to classifying stages of forest development across all forest types precludes our understanding of the current distribution of the mature and old-growth forest estate. Here, we propose functional definitions of mature and old-growth forests consistent with theories of forest stand development and evaluate the implications for assessing their spatial distribution nationwide. Using plot data from a national forest inventory and assuming space-for-time substitution, we modeled forest carbon accumulation over time using saturating, non-linear growth models. We define the onset of old-growth characteristics as occurring at the age when the density of total forest carbon stored in live and dead biomass reaches 95% of the empirically derived maximum, and the mature forest stage as occurring between the peak average carbon increment and the age of onset of old growth. We fit models within unique forest type-groups and, where possible, accounted for differences in site productivity. Population-level estimates of the mature and old-growth forest estate were calculated using sample design-based estimators. Across forest type-groups, the age at onset of old growth varied from 34 to 577 years, and the onset of mature forest conditions ranged between 16 and 313 years. Within forest type-groups, the effect of site quality on the age at onset of mature and old-growth forest varied but generally supported our hypothesis that high site quality accelerates forest development and increases forest carbon storage in old forests. We classified 6.3% of current forested lands in the United States as old growth and almost one-third as mature. Of the current old-growth forest estate, approximately 46% is found on federal public lands, and 11% is currently in congressional reserves. We posit that continued improvements to modeling the dynamic process of forest development and integration with structural definitions of old growth will be needed to ensure targets for old-growth retention and development are achieved.

First shotgun metagenomics study of Juan de Fuca deep-sea sediments reveals distinct microbial communities above, within, between, and below sulfate methane transition zones.

The marine deep subsurface is home to a vast microbial ecosystem, affecting biogeochemical cycles on a global scale. One of the better-studied deep biospheres is the Juan de Fuca (JdF) Ridge, where hydrothermal fluid introduces oxidants into the sediment from below, resulting in two sulfate methane transition zones (SMTZs). In this study, we present the first shotgun metagenomics study of unamplified DNA from sediment samples from different depths in this stratified environment. Bioinformatic analyses showed a shift from a heterotrophic, Chloroflexota-dominated community above the upper SMTZ to a chemolithoautotrophic Proteobacteria-dominated community below the secondary SMTZ. The reintroduction of sulfate likely enables respiration and boosts active cells that oxidize acetate, iron, and complex carbohydrates to degrade dead biomass in this low-abundance, low-diversity environment. In addition, analyses showed many proteins of unknown function as well as novel metagenome-assembled genomes (MAGs). The study provides new insights into microbial communities in this habitat, enabled by an improved DNA extraction protocol that allows a less biased view of taxonomic composition and metabolic activities, as well as uncovering novel taxa. Our approach presents the first successful attempt at unamplified shotgun sequencing samples from beyond 50 meters below the seafloor and opens new ways for capturing the true diversity and functional potential of deep-sea sediments.