Characterization of detritus profiles in some ecosystems of southern Sakhalin

The typology of the detritus profiles for the main forest types in the southern part of Sakhalin is developed for the first time. It is shown that their mean thickness varies from 4 to 8 cm and regularly decreases with increasing proportion of deciduous plants in the ground cover. It is found that this parameter agrees closely with the habitat conditions and the highest diversity of detritus profiles is observed under semihydromorphic conditions typical of alder stands. For the first time, it is proposed to assess the environmental favorability for humus formation using the Shannon index, the coefficient that relates the diversity level of the detritus profiles to the thickness of the humus horizon and enables the composition of ecological series. It is shown that the most favorable conditions for humus accumulation are created in the series birch forest–mixed coniferous forest–mixed deciduous forest. The applicability of the classification developed on the basis of studies in the forests of Primorye and Southern Yakutia to the forest ecosystems of Southern Sakhalin is confirmed.     

Effects of acidic deposition on soil ecosystems under forest in the Chongqing region of China

The effects of acidic deposition on soil ecosystems under temperate coniferous forest in the Chongqing region of China were investigated from 1993 to 1994. Precipitation, throughfall, stemflow, soil solutions, and soil samples were collected to estimate the acidification of soil ecosystems through the changes of their chemical components. The concentrations of ion species in the throughfall and stemflow under masson pine forest in Mt. Zhenwu were higher than those under mixed coniferous forest in Mt. Jinyun and under camphor tree forest in Laojundong, suggesting that Mt. Zhenwu is located in the vicinity of the Chongqing center and that it allowed the canopy of masson pine to intercept air pollutants. However, the level of aluminum dissolution into soil solutions was relatively low under masson pine forest in Mt. Zhenwu in spite of the low pH in the stemflow.     

Long‐term site productivity effects of different Rhododendron control methods in eastern beech (Fagus orientalis Lipsky) ecosystems in the Western Black Sea region of Turkey

The study area is located in an eastern beech stand on a fertile and mesic upland site in the western Black Sea region of Turkey. During natural regeneration of the beech stand, rhododendron was differentially controlled. The experiment used a randomized block design with four replicates and two different site preparation practices. The manual treatment was hand grubbing. The whole plant was uprooted and left on the site. The mechanical treatment scarified the surface soil to 5–10 cm depth with a bulldozer equipped with a brush rake. After 17 years following site preparation, the number of trees on the grubbing site (GS) was 60% more than that of mechanical treatment sites (MTS). Total tree biomass per hectare was 39% greater on GS than that of MTS. Beech trees on the grubbing sites had 18, 115, 29, 17 and 78% more N, P, K, Ca and Mg than MTS, respectively. Forest floor N content on GS was 50% more than that of MTS. On the GS, Ca content also was three times more than that of MTS. At 0–20 cm depth, cation exchange capacity on GS was 48% higher than that of MTS. At the same depth, GS had 50, 100, 78, 23, 8, 10 and 49% more C, N, P, Ca, K, Mg and S concentrations than those of MTS, respectively. Removing of organic layer and upper soil with mechanical site preparation depletes ecosystem nutrient pools compared with manual grubbing. This difference is sustained in the long‐term. Grubbing is both effective and by leaving organic layer on the sites, grubbing preserves the long‐term productivity of the ecosystem.     

The carbonate profile and water regime of migrational-mycelial chernozems in different ecosystems of Kursk oblast

The carbonate profiles of migrational-mycelial (typical) chernozems under regularly mown and absolutely reserved steppes in the V.V. Alekhin Central Chernozemic State Biospheric Reserve and under cropland with cereals (Kursk oblast) were studied in 2007–2009. A comparison of the results of these studies with previous results obtained in the mid-1970s attests to certain changes in the carbonate profiles of the soils. They are conditioned by the activation of the migration of carbonates and the more pronounced manifestation of differently directed processes of the leaching and accumulation of carbonates. The reasons for the observed transformation of the carbonate profiles are related to the increased moistening of the upper 3-m-deep chernozemic layer in different ecosystems because of a general rise in the humidity of the local climate in the recent decades (1973–2006).     

Modern geochemical evolution of lagoon-marshy landscapes in the western Caspian Sea region

The landscape-geochemical consequences of the full cycle of Caspian Sea fluctuations (regression-transgression-stabilization) that has taken place in the recent decades are analyzed. The regressive and lagoon-transgressive sets of landscape-geochemical processes (LGPs) are characterized. The impact of the regressive stage on the environment is seen in the development of the regressive LGPs in the soils and sediments of the coastal landscapes with a predominance of salinization and weak humus accumulation. The transgression of the sea was accompanied by the formation of specific lagoon-marsh landscapes, in which the accumulation of sulfides, gleyzation, iron oxidation, and humus formation were clearly pronounced. The general scheme of the evolution of the LGPs within the past 30 years is discussed. The rates of the humus accumulation and salinization during the stabilization stage are estimated. The organic matter reserves in the coastal soils increased by 1.5–2 times in a decade. The transformation of the particular forms of chemical elements in the lagoon-marsh landscapes upon fluctuations in the sea level is shown. The rise in the Caspian sea level was accompanied by the enhanced migration of elements with varying valences, such as Fe and Mn (as well as Zn, Cu, Pb, Ni, and Co) due to their mobilization in the slightly alkaline and neutral reducing conditions and their precipitation at the geochemical barriers.     

Biomass and respiration activity of soil microorganisms in anthropogenically transformed ecosystems (Moscow region)

In the forest, meadow, arable, and urban ecosystems (recreational, residential, and industrial zones) of Sergiev Posad, Shatura, Serpukhov, and Serebryanye Prudy districts of Moscow region, spatially separated sites (3–5 points per site) have been randomly selected and soil samples have been taken from the 0–10 (plant litter excluded) and 10- to 150-cm layers (a total of 201 samples have been taken). In the samples, the microbial biomass carbon (C_mic), the rate of the basal (microbial) respiration (BR), and the physical parameters (the particle size distribution (PSD), organic carbon (C_org), pH, heavy metals, and nutrients (NPK)) have been determined. High spatial variability has been revealed for C_mic and BR in all the ecosystems and the functional zones of the studied districts, and a clear tendency of a decrease in these parameters has been shown in the arable soils (by 1.4–3.2 times) and the industrial zone (by 1.7–3.3 times) compared to the natural analogues and other corresponding functional zones. It has been shown that the spatial distribution of the microbiological parameters is significantly (p ≤ 0.05) affected by the physicochemical properties of the soil (C_mic by the PSD and PSD × C_org; BR by the pH and pH × NPK; contributions of 40 and 63%, respectively), as well as by the type of ecosystem and the region of study (the contribution of the sum of these factors to the C_mic and BR was 56 and 67%, respectively). A tendency toward the deterioration of the functioning of the microbial community under the anthropogenic transformation of the soil has been shown. The contribution of the urban soils as a potential source of CO₂ emission to the atmosphere has been calculated and discussed.     

Nitrogen balances in forest ecosystems of the Pacific Northwest

In order to understand the role of nitrogen in the forests of the Pacific Northwest, especially Douglas-fir, a great number of studies have been initiated to evaluate both static and dynamic aspects of the nitrogen balance. This paper presents a summary of many of these past results covering 20 yr research with the specific intent of defining the nitrogen economy of these systems and the long- and short-term changes that are occurring. Variations of nitrogen in both soils and vegetation are discussed with some sampling techniques applicable to coniferous forests given. It appears that the soil total nitrogen, in different soils, varies several fold more than the nitrogen in the forest crops of these soils. The dynamics of nitrogen transfer within the ecosystem, together with gains and losses from the system, are presented.     

Parameters of the productivity of soil algae in terrestrial ecosystems

A review is presented of the recent state of the problem of soil algae productivity in terrestrial ecosystems on the basis of literature data and our own research. It is shown that the organic matter accumulated by soil algae is highly mobile. The following parameters were analyzed: the biological production, the time of the biomass turnover, and the rate of the algal organic matter renewal in the soil. The average monthly production of algae ranged from 0.9 to 765 g/m², the rate of the organic matter renewal ranged from 0.03 to 25.5 g/m² per day, and the time of the algal biomass renewal ranged from 0.1 to 7 days.     

Environmental biogeochemistry of mercury in Antarctic ecosystems

Polar regions are recognized as important sinks for long-range transport and deposition of Hg derived from natural and anthropogenic sources at lower latitudes. In previous studies we found enhanced Hg accumulation in soils, mosses and lichens from ice-free areas of Victoria Land facing the Terra Nova Bay coastal polynya. This study extends research to the distribution of organic C, total N, S, Hg, Al and Fe in surface soils, cyanobacterial mats and short sediment cores from four lacustrine ecosystems, each with different environmental characteristics and varying distances from the polynya. Results show that planktonic and benthic mats from lakes, along with mosses in the watershed, are the main sinks for Hg in summer meltwater. The C-normalized Hg concentrations in short sediment cores were higher in samples from lakes more exposed to marine aerosols from the coastal polynya. Reactive halogens in the aerosol promote the oxidation and deposition of atmospheric Hg in coastal ecosystems. The analysis of sediment cores did not reveal increasing Hg concentrations in recent sediments, except in the Lake 14 at Edmonson Point. The latter ice-free area is unaffected by the polynya and the increase in Hg concentrations in surface sediments could be due to local changes in lake water level and S biogeochemistry. Although change in sea ice coverage may enhance the role of Antarctic coastal ecosystems as sink in the global Hg cycle, our results seem to exclude possible risks for Antarctic terrestrial and freshwater organisms.     

Toxicological studies in tropical ecosystems: an ecotoxicological risk assessment of pesticide runoff in South Florida estuarine ecosystems

A multiyear study in the C-111 canal system and associated sites in Florida Bay was undertaken to determine the potential pesticide risk that exists in South Florida. After the examination of extensive pesticide concentration data in surface water, tissues, and semipermeable membrane devices (SPMDs), canal contamination seems to be derived from the extensive agricultural production that drains into the C-111 canal. The results of this study indicate that runoff from agricultural processes led to quantifiable pesticide residues in both canal and bay surface water, which occasionally exceeded current water quality criteria. The major pesticide of concern was endosulfan, which was detected at 100% of the sites sampled. Endosulfan exposure did not cause any acute effects in fish and crustaceans deployed in field bioassays. Chronic effects were observed in copepods, clams, and oysters but could not be attributed to endosulfan exposure. The decision to alter the C-111 canal flow and allow increased freshwater flow into the adjacent Everglades National Park may result in discharges of pesticides into the Everglades. Continued monitoring in this area is needed during this change in flow regime.     

Relationship between interannual variation of amino acid profile and pollen content in honey from a small Argentinian region

With the objective of evaluating the utility of the amino acid profile in the characterization of honey samples, 39 honey samples of two different harvests from a particular production zone in Córdoba, Argentina, were analyzed. Multivariate statistical techniques, such as principal component analysis (PCA), cluster analysis (CA), and multiple correspondence analysis (MCA), were applied to verify the correlation among the amino acid profiles, pollen percentages, and different harvests. PCA, CA, and MCA demonstrate the presence of differences of amino acid profiles between samples of the two harvests, such differences being mainly due to differences in pollen availability. Variation of the flora surrounding the apiary due to agricultural practices makes the analysis of amino acid profile typical for those cases with stabilized flora.     

Forest decline in the boreal montane ecosystems of the southern Appalachian Mountains

Research was initiated in 1984 in an attempt to quantify and test possible hypotheses for the systematic decline and mortality of red spruce (Picea rubens Sarg.) observed in the southern Appalachian Mountains. Field surveys have documented increases in decline symptoms. By 1986, 7% of all tagged red spruce trees in permanent plots were dead. This number, partially due to the effects of severe weather, increased to 41% in 1987. An insect and disease survey initiated in 1985 on 100 permanent plots has yielded little significant pathology or insect infestation. With the exception of the balsam wooly adelgid (Adelges picea (Ratz)), few signs or symptoms of disease or insect attack were noted on either Fraser fir (Abies fraseri) (Pursh Poir) or red spruce populations. Cultures from destructively-sampled root systems yielded few significant pathogens that could contribute to decline symptoms. Measurements of throughfall in 1986 yielded estimates of total wet deposition for NO₃ ^? and SO₄ ^2? of 25 and 75 kg ha^?1 yr^?1 respectively. Using net throughfall quantities, we estimate that between 40 and 60% of this input was due to cloud impact. Mean-volume-weighted pH per cloud event was 3.5. Over 75% of the cloud events sampled had a pH < 4.0. Cloud and rain water was dominated by H⁺, NH₄ ⁺, NO₃ ^?,, and SO₄ ^2? ions. Interaction with the forest canopy resulted in an enrichment of throughfall with base cations (K⁺, Ca²⁺, and Mg²⁺) and a loss of H⁺ and NH₄ ⁺. Mean-volume-weighted pH for throughfall was 3.9. The effects of simulated acidic cloud water on the epicuticular waxes of red spruce needles were studied during the summer of 1987. The cuticle proper of both 1986 and 1987 needles did not appear to be damaged by the treatments. The wax crystals which constitute the stomatal wax plugs, however, exhibited substantial degradation by simulated treatments at or below pH 3.5.     

The behavior of the clay fraction in model ecosystems of soil lysimeters

Changes in the mineralogical composition of the clay fraction (<0.001 mm) sampled from soils of the model lysimetric experiment of Moscow State University have been studied. The mineralogical composition of clay is represented by the paragenetic association of minerals typical of noncalcareous mantle loams in the center of the Russian Plain. The predominant smectitic phase consists of complex mixed-layered minerals (mica-smectite with high and low contents of the smectitic layers, chlorite-smectite with different ratios between the chloritic and smectitic layers) and individual smectites. Tri-and dioctahedral hydromica, kaolinite, chlorite, and clay-sized quartz are present in lower amounts. At the early stages of the experiment, the distribution of the smectitic phase in the soil profile is more contrasting than the distribution of the clay fraction. Under the impact of artificially planted meadows, forests, and agrocenoses, soil profiles with different distribution patterns of the clay fraction are formed. The weakly pronounced eluvial distribution pattern of the clay fraction has been registered. Under spruce and mixed stands, the loss of the clay fraction from the upper horizons is due to the hydrolysis of smectitic minerals in the acidified medium. Under broad-leaved stands, perennial herbs, agroecenoses, and fallow, the depletion of smectites from the upper horizons is due to lessivage. The relative accumulation of hydromica and kaolinite is observed in the uppermost soil layer.     

Long-term dynamics of Collembola in two contrasting ecosystems

The dynamics of collembolan communities were investigated in a spruce forest and in a dry natural meadow (Moscow Region, Russia) from 1991 to 1998. The long-term dynamics of springtail communities were compared to understand the role of external and internal factors responsible for changes over time. The two springtail communities were similiar in species richness (54 and 52 species), species diversity, as well as their rank/dominance distribution patterns. There were two dominant species in the forest, Isotomiella minor (Schäff.) and Parisotoma notabilis (Schäff.), and three in the meadow, P. notabilis, Lepidocyrtus lignorum (Fabr.) and Protaphorura armata Gisin. Community organization was much more stable over time in the forest than in the meadow. Population densities of the two dominant species changed synchronously and correlated with mean monthly temperature in the forest. In the meadow, densities of only some dominant species (P. notabilis and L. lignorum) correlated with each other and with temperature. It is supposed that a constant organization of collembolan communities through time arises as a result of successional changes over long periods with relatively stable conditions allowing the gradual formation of complexes of dominant species.     

Impact of acid precipitation on freshwater ecosystems in Norway

Extensive studies of precipitation chemistry during the last 20 yr have clearly shown that highly polluted precipitation falls over large areas of Scandinavia, and that this pollution is increasing in severity and geographical extent. Precipitation in southern Norway, Sweden, and Finland contains large amounts of H⁺, SO⁼ ₄, and NO^? ₃ ions, along with heavy metals such as Cu, Zn, Cd, and Pb, that originate as air pollutants in the highly industrialized areas of Great Britain and central Europe and are transported over long distances to Scandinavia, where they are deposited in precipitation and dry-fallout. In Norway the acidification of fresh waters and accompanying decline and disappearance of fish populations were first reported in the 1920s, and since then in Sørlandet (southernmost Norway) the salmon have been eliminated from several rivers and hundreds of lakes have lost their fisheries. Justifiably, acid precipitation has become Norway's number-one environmental problem, and in 1972 the government launched a major research project entitled ‘Acid precipitation — effects on forest and fish’, (the SNSF-project). Studies of freshwater ecosystems conducted by the SNSF-project include intensive research at 10 gauged watersheds and lake basins in critical acid-areas of southern Norway, extensive surveys of the geographical extent and severity of the problem over all of Norway, and field and laboratory experiments on the effect of acid waters on the growth and physiology of a variety of organisms. Large areas of western, southern, and eastern Norway have been adversely affected by acid precipitation. The pH of many lakes is below 5.0, and sulfate, rather than bicarbonate, is the major anion. Lakes in these areas are particularly vulnerable to acid precipitation because their watersheds are underlain by highly resistant bedrock with low Ca and Mg contents. Apart from the well-documented decline in fish populations, relatively little is known about the effects of acid precipitation on the biology of these aquatic ecosystems. Biological surveys indicate that low pH-values inhibit the decomposition of allochthonous organic matter, decrease the species number of phyto-and zooplankton and benthic invertebrates, and promote the growth of benthic mosses. Acid precipitation is affecting larger and larger areas of Norway. The source of the pollutants is industrial Europe, and the prognosis is a continued increase in fossil-fuel consumption. The short-term effects of the increasing acidity of freshwater ecosystems involve interference at every trophic level. The long-term impact may be quite drastic indeed.     

Mechanisms of N2O and NO production in the soil profile of a drained and forested peatland, as studied with acetylene, nitrapyrin and dimethyl ether

 Acetylene, dimethyl ether (DME) and 2-chloro-6-trichloromethyl pyridine (nitrapyrin) were used as inhibitors to study the contributions of nitrification and denitrification to the production of N₂O and nitric oxide (NO) in samples taken from the soil profile of a peatland drained for forestry. Acetylene and DME inhibited 60–100% of the nitrification activity in field-moist samples from the 0–5 cm and 5–10 cm peat layers, whereas nitrapyrin had no inhibitory effect. In the 0–5 cm peat layer the N₂O production could be reduced by up to 90% with inhibitors of nitrification, but in the 5–10 cm peat layer this proportion was 20–30%. All the inhibitors removed 96–100% of the nitrification potential in peat-water slurries from the 0–5 cm peat layer, but the 5–10 cm layer had a much lower nitrification activity, and here the efficiency of the inhibitors was more variable. Litter was the main net source of NO in the peat profile. NO₃ ^– production was lower in the litter layer than in the peat, whereas N₂O production was much higher in the litter than in the peat. Denitrification was the most probable source of N₂O and NO in the litter, which had a high availability of organic substrates. Received: 14 July 1997     

The properties and functions of biochars in forest ecosystems

Purpose

The production of large quantities of biochar from natural fires has been a part of human history for millennia, causing CO₂ emissions to the atmosphere and exerting long-term effects on soil processes. Despite its potential importance and recent work reflecting the wide interest in biochar, a general review of our deep understanding of biochar functions within forest soils is currently lacking. Gaps in research knowledge in this field are identified in this paper.

Materials and methods

This paper summarizes recent research to provide a better understanding of the concentrations, distribution, and characteristics of biochar produced from forest wildfire and its influences on soil processes. Perspectives and recommendations for future research on biochar in post-fire forest soils are also discussed.

Results and discussion

The concentration, distribution, and characteristics of biochar produced from forest wildfire largely depend on forest landscapes, regional climates, and mostly its feedstock and fire history, like, its duration and severity. The influences of biochar on soil processes, particularly carbon and nitrogen transformations and cycling, like, nitrification and nitrous oxide emissions reduction (Clough and Condron, J Environ Qual 39:1218–1223, 2010), are also determined mainly by the fire temperature and raw materials. Mechanisms can be attributed to the adsorption of organic compounds and nutrients or changed microenvironment, termed as charsphere, by biochar. We also identify the microbial mechanisms involved in the biochar-containing soils.

     

Seasonal variation of soil macrofauna in forest ecosystems of the Prioksko-Terrasnyi Biosphere Reserve

The study discusses the aspects of the seasonal dynamics of soil macrofauna in the forest ecosystems of the Prioksko-Terrasnyi Biosphere Reserve. The diversity of the group composition, total indices of biomass, and number of individuals are shown to grow from spring to autumn, while the dominant groups and structural characteristics remain unchanged. The composition of dominants and eudominants persists despite the abrupt changes in the number of individuals within the complexes.     

Soil-like bodies of autochemolithotrophic ecosystems in the caves of the Kugitangtau Ridge,eastern Turkmenistan

Ecosystems, in which the role of primary producers is played not by the photosynthetically active plants, but by the autochemolithotrophic microorganisms utilizing the chemical energy instead of the solar energy, have been described in the caves of eastern Turkmenistan. The zones of contact and interaction between the microorganisms and the mineral substrate perform the regulative, structuring, and bioaccumulative functions of surface soils. These zones have a vertically anisotropic profile forming in situ. Their functional and structural specificity makes it possible to consider them as bio-abiotic natural soil-like bodies and to apply the methods of pedology for their study.     

Biodiversity in soil ecosystems: the role of energy flow and community stability

In a series of community food webs from native and agricultural soils, we modeled energetics and stability, and evaluated the role of the various groups of organisms and their interactions in energy flow and community stability. Species were aggregated into functional groups based on their trophic position in the food webs. Energy flow rates among the groups were calculated by a model using observations on population sizes, death rates, specific feeding preferences and energy conversion efficiencies. From the energetic organization of the communities we derived the strengths of the mutual effects among the populations. These interaction strengths were found to be patterned in a way that is important to community stability. The patterning consisted of the simultaneous occurrence of strong top down effects at lower trophic levels and strong bottom up effects at higher trophic levels. These patterns resulted directly from the empirical data we used to parameterize the model, as we found no stabilizing patterns with random but plausible parameter values. Also, the impact of each individual interaction on community stability was established. This analysis showed that some interactions had a relatively strong impact on stability, whereas other interactions had only a small impact. These impacts on stability were neither correlated with energy flow nor with interaction strength. Comparison of the seven food webs showed that these impacts were sometimes connected to particular groups of organisms involved in the interaction, but sometimes they were not, which might be due to different trophic positions in the food webs. We argue that future research should be directed to answer the question which energetic properties of the organisms form the basis of the patterning of the interaction strengths, as this would improve our understanding of the interrelationships between energetics, community stability, and hence the maintenance of biological diversity.