The impact of energy-intensive industries on air quality in China’s industrial agglomerations

Understanding the driving forces of regional air pollution and its mechanism has gained much attention in academic research,which can provide scientific policy-making basis for economy-environment sustainability in China.Being an important energy and industrial base,the North China Plain region has been experiencing severe air pollution.Therefore,understanding the relationship between industrialization and air quality in this region is of great importance for air quality improvement.In this study,the average annual concentrations of SO2,NO2 and PM10 in 47 sample cities at and above the prefecture level in the North China Plain region from 2007 to 2016 were used to illustrate the spatiotemporal characteristics of air pollution within this region.Furthermore,panel data model,panel vector autoregression model,and impulse response function were used to explore the correlation and driving mechanism between energy-intensive industries and regional air quality.The results show that:first,overall air quality improved in the study area between 2007 and 2016,with a significant greater fall in concentration of SO2 than that of NO2 and PM10;second,provincial border areas suffered from severe air pollution and showed an apparent spatial agglomeration trend of pollution;and third,the test results from different models all proved that energy-intensive industries such as the chemical,non-metallic mineral production,electric and thermal power production and supply industries,had a significant positive correlation with concentrations of air pollutants,and indicated an obvious short-term impulse response effect.It concludes that upgradation of industrial structure,especially that of energy-intensive industries,plays a very important role in the improvement of regional air quality,which is recommended to be put in top priority for authorities.Therefore,policies as increasing investments in technological innovation in energy-intensive industries,deepening cooperation in environmental governance between different provinces and cities,and strengthening supervision and entry restrictions are suggested.     

What are the transitions of woodlands at the landscape level? Change trajectories of forest,non-forest and reclamation woody vegetation elements in a mining landscape in North-western Czech Republic

This study answers the following research questions: 1) What are the change trajectories of woody vegetation elements at the landscape level? 2) What are the differences in change trajectories amongst the various categories of forest, non-forest and reclamation woody vegetation? 3) How do the change trajectories differ in mining and non-mining landscapes? The study area, measuring 209.6 km², is located in the north-western part of the Czech Republic and may be broken down into 76.8 km² of mining landscape and 132.8 km² of non-mining landscape. Brown coal mining began in this region during the second half of the 18th century and led to the radical transformation of the landscape, including woodlands, during the second half of the 20th century. The source data for this study was obtained from the original stable cadastre maps (1842) and the landscape field mapping performed in 2010. The various woody vegetation elements (forest, non-forest, and reclamation woody plants) and land use/cover (LULC) categories were identified. The GIS symmetrical difference tool was subsequently used to perform an overlay analysis for the individual woody vegetation elements in order to study the change trajectories and to obtain information about the woodlands that have remained unchanged (continuous), the ones that have disappeared (extinct), and the ones that have newly appeared in the landscape (recent). In the case of the non-mining landscape, the total proportion of woodlands has increased (from 17 to 32%), but there has been a decline in the overall volume of forest woody plants found in these areas (from 93 to 74%). As far as the mining landscape is concerned, there has also been an increase in the area covered by woodlands (from 10 to 20%), however, the proportion of forest woody plants has decreased to a much greater extent (from 90 to 31%). From the perspective of extinct woody vegetation, 23.3% of all types of woodlands in the mining landscape may be classified as such, as compared to 10.8% in the non-mining landscape. The primary causes of this decline are mining activities and newly built-up areas. More continuous woody vegetation may be found in the non-mining landscape (42.1%) as compared to the mining landscape (15.4%). Recent woody vegetation, which has primarily replaced grasslands and partially arable land, prevails in both the mining (61.3%) as well as the non-mining (47.1%) landscapes. Different categories of woodlands (forest, non-forest, and reclamation woody vegetation elements) exhibit various change dynamics due to their different structure and the functions they serve. At the most basic level, there has been an overall increase in the occurrence of woodlands in the studied areas. However, once GIS spatial analysis is applied it is possible to see more complex processes in the development of woodland areas as characterised by gains and losses, and it is possible to identify mining and agricultural extensification as the two most significant factors behind the historical changes. Mining leads to a direct decrease in the area of woodlands; conversely, the spontaneous succession of vegetation resulting from agricultural extensification and forest reclamation facilitates woodland recovery. Forest reclamation and reforestation are essential on order to ensure the time continuity of woodlands in both types of landscape, i.e. mining and non-mining. The study presented in this paper proves that it is relevant to analyse the changes occurring in different woodland categories separately. The same methodology may be applied when studying the change dynamics of other important landscape elements, such as wood pastures and wetlands.     

Land tenure and forest cover change. The case of southwestern Beni,Bolivian Amazon, 1986–2009

As land use change continues to increase throughout the Amazon basin, there is a pressing need to accurately map, quantify and assess the effects of different factors on forest cover change (FCC). Land tenure may sometimes have important effects on forest cover, yet such effects remain poorly understood in Amazonia, particularly outside Brazil. In this paper we assess whether significant differences in trends of FCC can be partially explained by different land tenure arrangements, using a case study in southwestern Beni (Bolivian Amazon). We examine spatio-temporal dynamics of FCC across four land tenure systems (indigenous titled territory, protected area, logging concession, and private land) by classifying forests using a time-series of Landsat satellite imagery consisting of four dates (1986, 1996, 2001, 2009). Specifically, we unravel (1) trends in early growth and old-growth forest extent, including changes in total cover area, annual change rates, and spatial change dynamics, and (2) trends in old-growth forest fragmentation. To better understand the association between land tenure and FCC, we qualitatively assess the potential role that other underlying and proximate drivers may have had in FCC over the study period. We found that private lands underwent, by far, the largest FCC, that indigenous territories and the protected area had little FCC, and that logging concessions were responsible for the lowest FCC. Our findings suggest that land tenure played a key role in FCC except in private areas, where many other drivers had operated. Our study sheds light into the potential role of land tenure in FCC and has important implications for public policies aimed at socioeconomic development and environmental conservation in the Amazon. We give some policy recommendations drawn from a biocultural conservation perspective that could contribute to implement more inclusive conservation policies in the region.     

Water regime of the Argun’ river and Lake Hulun Nur under anthropogenic impact

In arid regions of Central Asia, cyclicity in the humidification behavior of a region shows long-term trends of changes in the water levels of closed lakes. Thus, the last 10 years saw a decrease in the water level by several meters on one of the region’s largest lakes — Hulun Nur (PRC). For water level stabilization on the PRC’s territory, a package of measures is undertaken for a partial Hailar river flow transfer (in the upper reaches of the Argun’ river) to Lake Hulun Nur. It is obvious that the lake’s water level regime will experience substantial changes. This paper discusses a variety of consequences of the river flow transfer and different water management modes, and forecasts the lake’s possible level regime, the Argun’ river discharge and the ecological consequences of measures of this kind for the Russian part of the drainage basin.     

The development of the aquatic ecosystem at Kråkenes Lake, western Norway, during the late glacial and early Holocene - a synthesis

This paper synthesises the palaeoecological reconstructions, including palaeoclimatic inferences, based on the available fossil record of plants (pollen, macrofossils, mosses, diatoms) and animals (chironomids, Cladocera, Coleoptera, Trichoptera, oribatid mites) in the late-glacial and early-Holocene sediments of Kråkenes Lake, western Norway, with special emphasis on changes in the aquatic ecosystem. New percentage and influx pollen diagrams for selected taxa provide insights into the terrestrial setting. The information from all the proxies is collated in a stratigraphical chart, and the inferred changes in the lake and its catchment are discussed. The individual fossil sequences are summarised by detrended correspondence analysis (DCA), and sample scores on the first DCA axes are plotted against an estimated calendar-year timescale for comparison of the timing and magnitude of changes in assemblage composition. The DCA plots show that the large late-glacial biotic changes were synchronous, and were driven by the overriding forcing factor of temperature. During the early Holocene, however, the changes in different groups were more gradual and were independent of each other, showing that other factors were important and interactive, such as the inwash of dissolved and particulate material from the catchment, the base and nutrient status of the lake-water, and the internal processes of ecosystem succession and sediment accumulation. This multi-disciplinary study, with proxies for changes in the lake and in the catchment, highlights the dependence of lake biota and processes not only on regional climatic changes but also on changes in the lake catchment and on internal processes within the lake. Rates of change for each group are also estimated and compared. The reaction times to the sharp temperature changes at the start and end of the Younger Dryas were very rapid and occurred within a decade of the temperature change. Aquatic organisms tracked the temperature and environmental changes very closely, and are probably the best recorders of late-glacial climatic change in the fossil record.     

Paleolimnological assessment of ecological integrity and eutrophication history for Lake Tiiläänjärvi (Askola,Finland)

In this study, we aim to reconstruct long-term limnoecological development of the clay-turbid Lake Tiiläänjärvi in Askola, southern Finland, using fossil Chironomidae assemblages. The study lake suffers from hypereutrophic conditions and late-winter and end-of-summer anoxia. The retrieved sediment record revealed a succession from oligo-mesotrophic (~AD 1940–2000) to eutrophic community (~AD 2000–2010) that finally reached hypereutrophic climax community in the most recent sediments. The initial state of the record was characterized by stable ecological conditions, but the biological integrity (community and functional diversity) was completely lost in the upper part of the sediment profile. The number of taxa markedly decreased following the nutrient enrichment and only one taxon (Chironomus plumosus-type), tolerant of temporary anoxia, remained in the surface sample. During the period of available observational data (since AD 1978), variance in midge community composition was mostly explained by limnological factors, namely total phosphorus (TP), whereas the influence of climate was statistically insignificant, thus enabling quantitative midge-based reconstruction of autumnal epilimnetic TP. The midge-based reconstruction showed an identical trend compared to sediment characteristics, which correspond to increased lake productivity and anthropogenic activities in the catchment. The inferred values for the initial state indicated mesotrophic conditions, which are typical for non-disturbed clay-turbid lakes in southern Finland, and a subsequent increase to eutrophic conditions, with hypereutrophic state reached at the top of the core. This development corresponds with the instrumentally monitored development. In addition, when the reconstruction was compared with the instrumental values, the inferences were mostly (75 % of the samples) within the error estimates of the model. The present results provide invaluable information on the limnoecological development of Lake Tiiläänjärvi, and more generally, support the theory that fossil remains of chironomids provide a useful tool for assessments of eutrophication history and biological integrity.     

Late-glacial and early-Holocene Coleoptera assemblages as indicators of local environment and climate at Kråkenes Lake, western Norway

Thirty-six Coleoptera (beetle) taxa and other insects were identified from the late-glacial and early-Holocene sediments at Kråkenes Lake. Compared with other Scandinavian late-glacial sites, this is a rather sparse record. The water beetles found in the Allerod are characteristic of a poorly vegetated clear-water lake. The terrestrial fauna is indicative of dwarf-shrub and moss vegetation. A marked decline in the number of species at the start of the Younger Dryas was rather rapid, probably over less than 80 calendar yrs. No obligate tundra species replaced the Allerod fauna. Most of the Younger Dryas is virtually devoid of beetles. The increase in numbers and diversity of both aquatic and terrestrial species at the Younger Dryas/Holocene transition is very rapid. After an initial pioneer stage, beetles associated with dwarf-shrub heath and willow scrub appeared, but no obligate tree or forest taxa were recorded.Mutual Climatic Range (MCR) temperature reconstructions suggest that the Allerod was colder and more continental than present. The near absence of beetles in the Younger Dryas probably reflects very cold conditions. A rapid temperature rise at the start of the Holocene resulted in a warmer and more continental climate than present.     

Chironomid-inferred late-glacial and early-Holocene mean July air temperatures for Kråkenes Lake, western Norway

A chironomid data-set calibrated to July air temperatures, based on 44 lakes in western Norway, is used to reconstruct mean July air temperatures from late-glacial and early-Holocene fossil chironomid assemblages at Kråkenes Lake. The calibration function is based on Weighted Averaging Partial Least Squares regression and has a root mean square error of prediction (RMSEP) of 1.13 °C, a r² of 0.69, and a maximum bias of 2.66 °C. All these statistics are based on leave-one-out cross-validation. A calibration function based on summer surface-water temperatures has a poorer performance (RMSEP = 2.22 °C, r² = 0.30, maximum bias = 5.29 °C). The reconstructed July air temperatures at Kråkenes rise to 10.5 °C soon after deglaciation, are about 11.5 °C in the Allerød, decrease to 9.5-10 °C in the Younger Dryas, and rise rapidly within 15 yrs to 11.5 °C at the onset of the Holocene. There is a two-step rise to 13 °C or more in the early-Holocene. The likely over-estimation of Younger Dryas temperatures and under-estimation of early-Holocene temperatures probably result from the limited temperature range represented by the existing calibration set. The data set is currently being expanded to include lakes with warmer air temperatures (> 14 °C) and with colder air temperatures (< 8 °C).     

Recent occurrence of large jökulhlaups at Lake Tuborg,Ellesmere Island,Nunavut

The varved sediment record from glacially-fed Lake Tuborg, Ellesmere Island, Nunavut, shows that only three large jökulhlaups have occurred there in the last millennium: 2003, 1993, and 1960. Detailed analyses of sediment microstructure and particle size, combined with in-situ hydrometeorological and limnological process studies, allowed jökulhlaup facies identification and discrimination from deposits from other processes. Deposits from large jökulhlaups are anomalously thick, typically lack internal structure, have sharp bases, and fine upwards. The ice-dammed lake above Lake Tuborg (the source of the jökulhlaups) likely changed its drainage style in 1960, from ice-dam overtopping to ice-dam flotation and glacial tunnel enlargement by melt widening, which allowed the lake to drain completely and catastrophically. Complete drainage of ice-dammed lakes by ice-dam flotation is rare in the region is due to the pervasiveness of cold-based ice. Twentieth century warming is likely responsible for some combination of dam thinning, lake expansion and deepening, and changing the thermal regime at the base of the dam. Anomalously thick individual varves were periodically deposited beginning in the nineteenth century, and their thickness increased with time. This likely reflects a combination of increased ice dam overtopping, subaqueous slope failures, sediment availability and rising air temperature. The varve record presented here significantly correlates with a previous, shorter record from Lake Tuborg. However, generally weak correlations are found between the new varve time series, regional records of air temperature, and glacial melt from ice cores on the Agassiz Ice Cap. It is hypothesized that on short timescales, sedimentation at the coring location reflects a complex and varying integration of multiple hydroclimatic, geomorphic and limnologic influences.     

‘A land history of men’: The intersection of geomorphology,culture and heritage in Cornwall,southwest England

Relationships between landscape-scale geomorphology and aspects of the human environment (including heritage and material cultures) are best examined in landscapes with a strong geomorphological imprint of past climatic and environmental changes, and where human activity has been present for a long period of time. In Cornwall, southwest England, a strong geomorphological signature is imparted by weathering of granite bedrock under cold Quaternary climates, and a strong cultural and heritage imprint is manifested in material and nonmaterial ways through archaeology, art, literature and folklore, and is illustrated in this paper through examples of Bodmin Moor (north Cornwall) and West Penwith (west Cornwall). Landscapes of Bodmin Moor include wide valleys with underfit rivers and upland summits with prominent tors, resulting from granite weathering and slope processes during the Tertiary and Quaternary. Pollen records show how human activity has changed on the moor over time, with a peak of settlement during the Bronze Age, and expansion of grazing into the Iron Age. Daphne du Maurier's novels, set on or adjacent to Bodmin Moor, emphasize the moor's relationship to unstable and intense human emotions and crises. In West Penwith, which is geomorphological similar to Bodmin Moor, geomorphology–culture relations are demonstrated in different ways but through a similar sense of place and regional identity. The St Ives School of early 20th Century art, including the local artist Peter Lanyon and the sculptor Barbara Hepworth, draws inspiration from the local land and seascapes. The oral traditions and folklore of Zennor emphasize the importance of witchcraft and superstition that are in part founded on the wildness of upland summits and stormy coastline. Across West Penwith, tin mining and the mining trade exerted a strong impact on regional socioeconomic and cultural development from the Bronze Age until the end of the 19th Century, seen through settlement patterns, scientific innovation and Nonconformism. Today these geomorphology–culture relations are memorialized in the Cornwall and West Devon Mining Landscape World Heritage Site.     

The recording of floods and earthquakes in Lake Chichój,Guatemala during the twentieth century

Laguna Chichój (Lake Chichój) is the only deep permanent lake in the central highlands of Guatemala. The lake is located in the boundary zone between the North American and Caribbean plates. The lake has been struck by devastating earthquakes and tropical cyclones in historical times. We investigated the imprint of twentieth century extreme events on the sedimentary record of this tropical lake using a bathymetric survey of the lake, coring the lake floor, and providing a chronology of sediment accumulation. The lake occupies a series of circular depressions likely formed by the rapid dissolution of a buried body of gypsum. ²¹⁰Pb and ¹³⁷Cs inventories and varve counting indicate high rates of sedimentation (1–2 cm year^?1). The annually layered sediment is interrupted by turbidites of two types: a darker-colored turbidite, enriched in lake-derived biogenic constituents, and interpreted as a seismite, and a lighter-colored type, enriched in catchment-derived constituents, interpreted as a flood layer. Comparison of our ¹³⁷Cs-determined layer ages with a catalog of twentieth century earthquakes shows that an earthquake on the Motagua fault in 1976 generated a conspicuous darker-colored turbidite and slumped deposits in separate parts of the lake. The entire earthquake inventory further reveals that mass movements in the lake are triggered at Modified Mercalli Intensities higher than V. Tropical cyclonic depressions known to have affected the lake area had limited effect on the lake, including Hurricane Mitch in 1998. One storm however produced a significantly thicker flood layer in the 1940s. This storm is reportedly the only event to have generated widespread slope failures in the lake catchment. It is thus inferred that abundant landsliding provided large amounts of concentrated sediment to the lake, through hyperpycnal flows.     

A multi-proxy record of the Last Glacial Maximum and last 14,500?years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska

Sediment cores from Lone Spruce Pond (60.007°N, 159.143°W), southwestern Alaska, record paleoenvironmental changes during the global Last Glacial Maximum (LGM), and during the last 14,500 calendar years BP (14.5?cal?ka). We analyzed the abundance of organic matter, biogenic silica, carbon, and nitrogen, and the isotope ratios of C and N, magnetic susceptibility, and grain-size distribution of bulk sediment, abundance of alder shrub (Alnus) pollen, and midge (Chironomidae and Chaoboridae) assemblages in a 4.7-m-long sediment sequence from the depocenter at 22?m water depth. The basal unit contains macrofossils dating to 25?C21?cal?ka (the global LGM), and is interpreted as glacial-lacustrine sediment. The open water requires that the outlet of the Ahklun Mountain ice cap had retreated to within 6?km of the range crest. In addition to cladocerans and diatoms, the glacial-lacustrine mud contains chironomids consistent with deep, oligotrophic conditions; several taxa associated with relatively warm conditions are present, suggestive of relative warmth during the global LGM. The glacial-lacustrine unit is separated from the overlying non-glacial lake sediment by a possible disconformity, which might record a readvance of glacier ice. Non-glacial sediment began accumulating around 14.5?cal?ka, with high flux of mineral matter and fluctuating physical and biological properties through the global deglacial period, including a reversal in biogenic-silica (BSi) content during the Younger Dryas (YD). During the global deglacial interval, the ??¹³C values of lake sediment were higher relative to other periods, consistent with low C:N ratios (8), and suggesting a dominant atmospheric CO₂ source of C for phytoplankton. Concentrations of aquatic faunal remains (chironomids and Cladocera) were low throughout the deglacial interval, diversity was low and warm-indicator taxa were absent. Higher production and air temperatures are inferred following the YD, when bulk organic-matter (OM) content (LOI 550?°C) increased substantially and permanently, from 10 to 30?%, a trend paralleled by an increase in C and N abundance, an increase in C:N ratio (to about 12), and a decrease in ??¹³C of sediment. Post-YD warming is marked by a rapid shift in the midge assemblage. Between 8.9 and 8.5?cal?ka, Alnus pollen tripled (25?C75?%), followed by the near-tripling of BSi (7?C19?%) by 8.2?cal?ka, and ??¹⁵N began a steady rise, reflecting the buildup of N and an increase in denitrification in soils. Several chironomid taxa indicative of relatively warm conditions were present throughout the Holocene. Quantitative chironomid-based temperature inferences are complicated by the expansion of Alnus and resulting changes in lake nutrient status and production; these changes were associated with an abrupt increase in cladoceran abundance and persistent shift in the chironomid assemblage. During the last 2,000?years, chironomid-assemblage changes suggest cooler temperatures, and BSi and OM values were generally lower than their maximum Holocene values, with minima during the seventh and eighth centuries, and again during the eighteenth century.     

A 2000 year record of climatic change at Ongoke Lake,southwest Alaska

We analyzed sediments of the past 2000 years from Ongoke Lake, southwest Alaska, for organic carbon, organic nitrogen, biogenic silica (BSi), and diatom assemblages at decadal to centennial resolution to infer limnological changes that may be related to climatic variation in southwestern Alaska. The chronology is based on a ²¹⁰Pb profile from bulk sediments and nine AMS ¹⁴C ages from terrestrial plant macrofossils. Four of the ¹⁴C ages span a core depth interval of 60.5 cm but are statistically indistinguishable from one another with a mean of ~1300 AD, which compromises the determination of temporal trends at Ongoke Lake and comparison with other paleoclimate records. The diatom record suggests changes in the duration of ice cover and strength of thermal stratification that are probably related to temperature variation. This variation includes a cold interval around the first millennium cooling (FMC) and a warm interval spanning the medieval climate anomaly (MCA). However, the lake-sediment record shows no clear signals of temperature variation for the period of the Little Ice Age (LIA) or the twentieth century. Climatic changes during these periods may have been manifested through effective-moisture (precipitation minus evapotranspiration) variation in the Ongoke Lake area. We estimate water depths and infer effective-moisture fluctuations by applying a regional transfer function to our diatom record. Together with inferences from diatom autecologies, this water-depth reconstruction suggests that effective moisture increased steadily from 50 BC to 350 AD, which was followed by relatively dry conditions between 550 and 750 AD and relatively wet conditions between 750 and 1450 AD. Effective moisture was low from ~1450 to 1850 AD, coinciding with the LIA; an alternative age model places this interval between ~1315 and 1850 AD. During the past 150 years, effective moisture increased, with estimated water depths reaching peak values in the second half of the twentieth century. This study offers the first paleolimnological record for inferring centennial-scale climatic variation over the past two millennia from southwestern Alaska.

The role of visualisation in the choice of stationary non-separable space–time covariance functions: an application to air pollution data

Modelling spatio-temporal dependencies resulting from dynamic processes that evolve in both space and time is essential in many scientific fields. Spatio-temporal Kriging is one of the space–time procedures, which has progressed the most over the last few years. Kriging predictions strongly depend on the covariance function associated with the stochastic process under study. Therefore, the choice of such a covariance function, which is usually based on empirical covariance, is a core aspect in the prediction procedure. As the empirical covariance is not necessarily a permissible covariance function, it is necessary to fit a valid covariance model. Due to the complexity of these valid models in the spatio-temporal case, visualising them is of great help, at least when selecting the set of candidate models to represent the spatio-temporal dependencies suggested by the empirical covariogram. We focus on the visualisation of the most interesting stationary non-separable covariance functions and how they change as their main parameters take different values. We wrote a specialised code for visualisation purposes. In order to illustrate the usefulness of visualisation when choosing the appropriate non-separable spatio-temporal covariance model, we focus on an important pollution problem, namely the levels of carbon monoxide, in the city of Madrid, Spain.     

Environmental history of an urban lake: a palaeolimnological study of Lake Jyväsjärvi, Finland

Sedimentary diatom frustules and chironomid remains, in addition to the chemical stratigraphy of 32 elements and organic pollutants such as resin acids, PCB, DDT and its metabolites, were studied from core samples taken from Lake Jyväsjärvi in Central Finland (64° 14 N, 25° 47 E). The sediment profile covered over 200 years, with the oldest samples representing a period of very low human interference. The town of Jyväskylä was established on the lake shore in 1837, and the lake received untreated municipal wastewater from the town up until, 1977. A paper mill started operations in 1872 and began discharging effluent into Lake Jyväsjärvi. In recent years this effluent loading has been reduced. Based on the biological and chemical properties of the sediment strata, five developmental phases were distinguished and named as follows: (1) a pre-industrial phase (approximately up until the 1860s); (2) a phase of early changes in the lake ecosystem (from the 1870s to ca. 1940s); (3) a phase of increasing eutrophication (from ca. 1950 to ca. 1965); (4) a phase of severe pollution (from ca. 1966 to the early-1990s); and (5) a phase of recovery, which proceeded more quickly during the late-1990s following long-term hypolimnetic aeration. It was estimated that the ecological status of the lake changed from good to moderate during the second phase. Due to the poor chemical status of the lake (including increased concentrations of harmful substances) and the pronounced changes in diatom and chironomid communities, the ecological status from 1950 to the early-1990s was classified as bad. The present ecological status, after a slow recovery of about 20 years, can be classified as moderate/poor. Chemical analysis of the sediment revealed that some elements (C, N, P, S, Ba, Cd, Cu, Fe, Pb, Ni and Zn) followed the known history of municipal waste water discharge into the lake, but Hg, Cr and persistent organic pollutants had different stratigraphies, and therefore mainly originated from other sources. Pronounced changes in profundal benthic communities (chironomids) started about 80 years later than those in diatoms, but later changes in chironomid assemblages were greater than those in diatoms.     

On the organic compounds in water of Mochou Lake and Heart Lake in Larsemann Hills,Antarctica

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Sediment lithology and stable isotope composition of organic matter in a core from a cirque in the Krkonoše Mountains,Czech Republic

This study presents detailed lithostratigraphy and stable carbon and nitrogen isotopic variations in a 520-cm-long sediment core from a cirque basin in the Labsky důl Valley, Krkonoše Mountains, Czech Republic. Detailed study of the core reveals five major periods of sedimentation during the last 7600 years: silt and sand deposition during ~7.6–5.1 ka cal BP, Sphagnum peat accumulation during ~5.1–4.0 ka cal BP, sandy silt and sand during ~4.0–2.8 ka cal BP, raised peat bog during ~2.8–2.0 ka cal BP (Sphagnum peat), and sedimentation of sandy silt since ~2.0 ka cal BP. The δ¹³C values of the organic matter in the core vary in the range typical for C3 plants, from −24.35 to −27.68‰, whereas the δ¹⁵N values vary from −2.65 to +4.35‰. Core sections having ash contents ≥70% have δ¹⁵N > 1‰ and δ¹³C < −26‰, whereas those having ≤70% ash content have δ¹⁵N < 1‰ and δ¹³C > −26‰. Strong linear correlations are observed between δ¹³C and δ¹⁵N values as well as between C:N ratios and δ¹⁵N values in the horizons with ash content >10%, primarily for sand and silt horizons. On the other hand, poor correlations between δ¹³C and C:N ratio, as well as δ¹⁵N and C:N ratio, were observed in Sphagnum peat layers (45–125 and 185–265 cm). We conclude that the primary stable isotope variations are not preserved in the layers where significant correlation between δ¹⁵N and C:N ratio is observed. The relatively small δ¹³C variation in the uppermost Sphagnum peat layer suggests stable temperature during ~2.8–2.0 ka cal BP.     

Mining pollution triggered a regime shift in the cladoceran community of Lake Kirkkojärvi,southern Finland

Mining is one of the key industries in the world and mine water pollution is a serious threat to aquatic ecosystems. Historical monitoring data on the pollution history and impacts in aquatic ecosystems, however, are rarely available, so paleolimnological methods are required to explore the consequences of past pollution. We studied the history of cladoceran community dynamics in Lake Kirkkojärvi, southern Finland, including the periods before, during and after mining. We analyzed the geochemical composition and cladoceran subfossil remains in a ²¹⁰Pb-dated sediment core to evaluate the magnitude, rate, and direction of cladoceran community changes through time. The cladoceran community was altered significantly by mining activity that occurred during the mid-twentieth century. During more recent times, however, eutrophication effects have overridden the impacts of mining. After mining ceased, the cladoceran community underwent an abrupt regime shift towards taxa that reflect more eutrophic conditions. This change was caused by intensive farming activity and fertilizer use over the past few decades. The recent history of Lake Kirkkojärvi is a textbook example of a regime shift triggered by multiple human-caused stressors. Our findings also highlight the utility of cladocerans as bio-indicators in pollution research and illustrate the sensitivity of aquatic ecosystems to anthropogenic modification.     

The impact of COVID-19 on China’s regional economies and industries

Scientifically assessing the economic impact of major public health emergencies,containing their negative effects,and enhancing the resilience of an economy are important national strategic needs.The new coronavirus disease (COVID-19) has,to date,been effectively contained in China,but the threat of imported cases and local risks still exist.The systematic identification of the virus's path of influence and intensity is significant for economic recovery.This study is based on a refined multi-regional general equilibrium analysis model,which measures the economic and industrial impacts at different epidemic risk levels in China and simulates development trends and the degree of damage to industries and the economy under changes to supplies of production materials and product demand.The results show that,at the macroeconomic level,China's GDP will decline about 0.4％ to 0.8％ compared to normal in 2020,with an average drop of about 2％ in short-term consumption,an average drop in employment of about 0.7％,and an average increase in prices of about 0.9％.At the industry level,the epidemic will have the greatest short-term impact on consumer and laborintensive industries.For example,the output value of the service industry will fall 6.3％ compared to normal.Looking at the impact of the epidemic on the industrial system,the province most affected by the epidemic is Hubei,which is the only province in China in the level-1 risk category.As the disease spread outward from Hubei,there were clear differences in the main industries that were impacted in different regions.In addition,simulation results of recovery intensity of regional economies under the two epidemic response scenarios of resumption of work and production and active fiscal stimulus policies show that an increase in fiscal stimulus policies produces a 0.3％ higher rate of gross regional product growth but it causes commodity prices to rise by about 1.8％.Measures to resume work and production offer a wider scope for industrial recovery.