Institute of Hydroecology

Abstract Inadvertent release of petroleum products such as gasoline into the subsurface can initiate ground water contamination, particularly by the toxic, water‐soluble and mobile gasoline components: benzene, toluene and xylenes (BTX). This study was undertaken to examine the processes controlling the rate of movement and the persistence of dissolved BTX in ground water in a shallow, unconfined sand aquifer. Water containing about 7.6 mg/ L total BTX was introduced below the water table and the migration of contaminants through a sandy aquifer was monitored using a dense sampling network. BTX components migrated slightly slower than the ground water due to sorptive retardation. Essentially all the injected mass of BTX was lost within 434 days due to biodegradation. Rates of mass loss were similar for all monoaromatics; benzene was the only component to persist beyond 270 days. Laboratory biodegradation experiments produced similar rates, even when the initial BTX concentration varied. A dominant control over BTX biodegradation was the availability of dissolved oxygen. BTX persisted at the field site in layers low in dissolved oxygen. Decreasing mass loss rates over time observed in the field experiment are not likely due to first‐order deeradation rates, but rather to the persistence of small fractions of BTX mass in anoxic layers.

Abstract Bank filtration and artificial ground water recharge are important, effective, and cheap techniques for surface water treatment and removal of microbes, as well as inorganic, and some organic, contaminants. Nevertheless, physical, chemical, and biological processes of the removal of impurities are not understood sufficiently. A research project titled Natural and Artificial Systems for Recharge and Infiltration attempts to provide more clarity in the processes affecting the removal of these contaminants. The project focuses on the fate and transport of selected emerging contaminants during bank filtration at two transects in Berlin, Germany. Several detections of pharmaceutically active compounds (PhACs) in ground water samples from bank filtration sites in Germany led to furthering research on the removal of these compounds during bank filtration. In this study, six PhACs including the analgesic drugs diclofenac and propyphenazone, the antiepileptic drugs carbamazepine and primidone, and the drug metabolites clofibric acid and 1‐acetyl‐1‐methyl‐2‐dimethyl‐oxamoyl‐2‐phenylhydrazide were found to leach from the contaminated streams and lakes into the ground water. These compounds were also detected at low concentrations in receiving public supply wells. Bank filtration either decreased the concentrations by dilution (e.g., for carbamazepine and primidone) and partial removal (e.g., for diclofenac), or totally removed PhACs (e.g., bezafibrate, indomethacine, antibiotics, and estrogens). Several PhACs, such as carbamazepine and especially primidone, were readily transported during bank filtration. They are thought to be good indicators for evaluating whether surface water is impacted by contamination from municipal sewage effluent or whether contamination associated with sewage effluent can be transported into ground water at ground water recharge sites.

Abstract GRACE satellite data are widely used to estimate groundwater storage (GWS) changes in aquifers globally; however, comparisons with GW monitoring and modeling data are limited. Here we compared GWS changes from GRACE over 15 yr (2002–2017) in 14 major U.S. aquifers with groundwater‐level (GWL) monitoring data in ~23,000 wells and with regional and global hydrologic and land surface models. Results show declining GWS trends from GRACE data in the six southwestern and south‐central U.S. aquifers, totaling −90 km 3 over 15 yr, related to long‐term (5–15 yr) droughts, and exceeding Lake Mead volume by ~2.5×. GWS trends in most remaining aquifers were stable or slightly rising. GRACE‐derived GWS changes agree with GWL monitoring data in most aquifers (correlation coefficients, R = 0.52–0.95), showing that GRACE satellites capture groundwater (GW) dynamics. Regional GW models (eight models) generally show similar or greater GWS trends than those from GRACE. Large discrepancies in the Mississippi Embayment aquifer, with modeled GWS decline approximately four times that of GRACE, may reflect uncertainties in model storage parameters, stream capture, pumpage, and/or recharge rates. Global hydrologic models (2003–2014), which include GW pumping, generally overestimate GRACE GWS depletion (total: approximately −172 to −186 km 3 ) in heavily exploited aquifers in southwestern and south‐central U.S. by ~2.4× (GRACE: −74 km 3 ), underscoring needed modeling improvements relative to anthropogenic impacts. Global land surface models tend to track GRACE GWS dynamics better than global hydrologic models. Intercomparing remote sensing, monitoring, and modeling data underscores the importance of considering all data sources to constrain GWS uncertainties.

Sex controls have been performed in some farmed fish species because of significant growth differences between females and males. In yellow catfish (Pelteobagrus fulvidraco), adult males are three times larger than female adults. In this study, six Y- and X-linked amplified fragment length polymorphism fragments were screened by sex-genotype pool bulked segregant analysis and individual screening. Interestingly, sequence analysis identified two pairs of allelic genes, Pf33 and Pf62. Furthermore, the cloned flanking sequences revealed several Y- and X-specific polymorphisms, and four Y-linked or X-linked sequence characterized amplified region (SCAR) primer pairs were designed and converted into Y- and X-linked SCAR markers. Consequently, these markers were successfully used to identify genetic sex and YY super-males, and applied to all-male population production. Thus, we developed a novel and simple technique to help commercial production of YY super-males and all-male populations in the yellow catfish.

Previous palaeoclimatic studies in the northeastern Qinghai-Tibetan Plateau (NETP) during the Holocene, mainly using lake sediments, have deepened our understanding of the climatic system in this remote region. The timing and forcing mechanisms of climatic change in this region are still controversial, however. Aeolian sand and silt deposits, which are widely distributed in the NETP, can be readily dated by optically stimulated luminescence (OSL) techniques and reveal the sensitive response of the landscape to climatic change. In this study, aeolian sand and loess at six sites around Qinghai Lake were studied to reconstruct millennial-scale climatic changes during the Holocene. Multiproxy data along with 24 OSL age determinations show that low effective moisture and aeolian activity occurred at c. 13 ka, 10—9.1 ka, and 8.9—7.8 ka. Periods of greater effective moisture may have occurred at ~11 ka and 9 ka, and there is evidence for a previously undocumented wet climate at 4—3 ka. These results show that millennial-scale Holocene palaeoclimatic changes in the NETP cannot be explained simply as direct responses to changes in monsoon precipitation forced by summer insolation. We suggest that changes in effective moisture were determined by the balance between monsoon-induced rainfall and evaporation loss (mainly controlled by temperature). Thus, climatic change in the NETP may have been influenced by complex interactions between the monsoon circulation and local convection/evaporation effects, in addition to large-scale change in the Asian monsoon and the westerlies.

Abstract Clarifying mechanisms underlying the ecological succession of gut microbiota is a central theme of gut ecology. Under experimental manipulations of zebrafish hatching and rearing environments, we test our core hypothesis that the host development will overwhelm environmental dispersal in governing fish gut microbial community succession due to host genetics, immunology, and gut nutrient niches. We find that zebrafish developmental stage substantially explains the gut microbial community succession, whereas the environmental effects do not significantly affect the gut microbiota succession from larvae to adult fish. The gut microbiotas of zebrafish are clearly separated according to fish developmental stages, and the degree of homogeneous selection governing gut microbiota succession is increasing with host development. This study advances our mechanistic understanding of the gut microbiota assembly and succession by integrating the host and environmental effects, which also provides new insights into the gut ecology of other aquatic animals.

Abstract Two methods were used to approximate site‐specific biodegradation rates of monoaromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylenes [BTEX]) dissolved in ground water. Both use data from monitoring wells and the hydrologic properties of the quifer to estimate a biodegradation rate constant that can be used in ground water solute fate and transport models. The first method uses a biologically recalcitrant tracer in the ground water associated with the hydrocarbon plume to normalize changes in concentration of BTEX under anaerobic conditions; attenuation of the tracer is attributed to dilution, sorption, and/or volatilization. Attenuation of BTEX in excess of the attenuation of the tracer is attributed to biodegradation, although other processes may affect the observed rate. The second method assumes that the plume has evolved to a dynamic steady‐state equilibrium. A one‐dimensional analytical solution to the advection‐dispersion equation is used to extract the rate of attenuation that would be necessary to produce a steady‐state plume of the configuration found at the site. Attention is attributed largely to biodegradation bacause the analytical solution removes the effects of sorption and dispersion and volatilization is assumed to be minimal. Neither method fully accounts for the effects of continuing dissolution of BTEX in the source area or nonlinear sorption. Therefore, the rats cannot be attributed fully to biodegradation, but still are useful for ground water contaminant fate and transport modeling. The methods were applied to a data set from a JP‐4 jet fuel spill at Hill Air Force Base, Utah. In estimats along two seprate flow paths, natural attenuation rates for BTEX ranged form 0.006 to 0.038 day −1 , with most rates near 0.02 day −1 . The rate for benzene ranged from 0.025 to 0.038 day −1 . The rates of attenuation of individual BTEX compounds as estimated by the two methods were in close aggrement. For an individual compound, the rate estimated using the second method was at most 36 percent greater than, but usually within 20 percent of, the rate estimated using the first method, suggesting that intrinsic bioremediation was the dominant process that attenuated BTEX.

ABSTRACT High‐resolution pollen and charcoal records from Qinghai Lake in south‐western China are presented. The records reveal variations in vegetation, fire and climate history since 18 500 cal a BP. The results show that seven significant vegetation changes are recorded, which are responses to climate changes and/or fire events. Frequent and intensive fires occurred during the periods 17 900–15 000, 13 000–11 500 and 4280–980 cal a BP, corresponding to relatively dry climatic conditions. Combined with the climatic record from Tiancai Lake, the regional climatic changes since 18 500 cal a BP in western Yunnan Province are reconstructed. Namely, the Heinrich Event 1, the Bølling–Allerød warm period and the Younger Dryas event during the last deglaciation are ubiquitous in western Yunnan Province. The start of the Holocene is recorded at 11 500 cal a BP. The Holocene climatic optimum occurred between 8450 and 4280 cal a BP. After 4280 cal a BP, the climate deteriorated, accompanied by evidence for human impact. Based on this study, we consider that vegetation and climatic changes since 18 500 cal a BP in south‐western Yunnan Province are primarily driven by September and average summer solar insolation, with some associated influence from regional sea‐surface temperature and sea‐level rise.

Chinese perch are one of the most valuable food fish in China, but the sole source of feed for intensive culture is live prey fish. Our previous studies on systematic sensory physiology revealed that this species have a mechanism for this peculiar feeding habit. In the present study, a specific training procedure was designed, and both experimental (initial body weight 171.0 g; 120 days) and commercial (initial body weight 52.4 g; 240 days) net-cage cultures were conducted to investigate the training success, growth performance and survival of the trained yearlings fed with nonlive or Oregon-type moist diet. The training successes of minced prey fish and the Oregon moist diet were 100 and 89.9%, respectively, in experimental culture, and 92.2 and 83.5% in commercial culture. In an experimental trial, the fish fed minced prey fish or the Oregon moist diet attained final body weights of 472.7 g or 344.7 g, although the specific growth rates of these groups were significantly lower than that of the fish fed live prey fish (final body weight 560.0 g). Mortality was not significantly related to dietary treatment. In commercial culture, the final body weights were as follows: 750 g on live prey fish, 705 g on minced prey fish and 651 g on the Oregon moist diet. Feed costs to produce 1 kg fish were estimated to be US$6.59 for live prey fish, US$1.76 for minced prey fish and US$2.07 for the Oregon moist diet. The results of the present study confirmed that sensory modality and associative learning appear to be critical factors in determining food discrimination of Chinese perch, indicating that both minced trash fish and Oregon-type moist diet can be substituted for live prey fish in intensive commercial production.

Abstract The history of dust emission and eolian activity in dust source areas remains unclear due to the scarcity of geological archives. Grain‐size data from Genggahai Lake on the northeastern Qinghai‐Tibetan Plateau show that sand‐sized particles in the lake sediments were transported primarily by strong winds to the lake and therefore can be used as a proxy for eolian activity. Eolian activity was weak from 10.3 to 6.3 ka, which may be a response to increased vegetation cover due to the strengthened Asian summer monsoon. In contrast, eolian activity occurred episodically when the summer monsoon weakened. The abrupt, intense sand deposition events are likely to have resulted from strong wind regimes, in turn linked to cooling events in the North Atlantic. Our results suggest that changes in atmospheric circulation patterns may have strongly affected the moisture balance and wind strength in the dust source area and hence dust emissions.

PURPOSE: High-altitude exposure is often associated with gastrointestinal disorders, inflammation, and an increased risk of infection. We suspected microbial and immunological responses to high-altitude exposure in mountaineers resulting from changes in the balance of the intestinal microflora. METHODS: We investigated fecal samples and serum of seven mountaineers who took part in a 47-d German expedition to the Nepalese Himalayas in 2002, for microbial response by changes in different fecal bacterial population groups (fluorescent in situ hybridization), immune response by serum levels of IgG-, IgM-, and IgA anti-LPS (E. coli J5), and inflammatory response by serum levels of C-reactive protein (CRP) (ELISA). In addition, measurements of body temperature, pulse rate, arterial oxygen saturation, and questionnaire (Lake Louise score for altitude illness) were performed. RESULTS: The data indicate a distinct alteration in the composition of the fecal microflora relative to high-altitude exposure above 5000 m. Bifidobacteria and species belonging to the Atopobium, Coriobacterium, and Eggerthella lenta group decreased, whereas potential pathogenic bacteria of the gamma subdivision of Proteobacteria and specific Enterobacteriaceae such as Escherichia coli increased. Possible endotoxemia resulting from the increase of the latter Gram-negative bacteria was indirectly indicated by the reduction in serum levels of IgM- and/or IgA anti-LPS. CRP was elevated relative to high-altitude exposure. The Lake Louise score correlated with the changes in CRP, IgA-, and IgM anti-LPS but did not correlate with the bacterial alterations. CONCLUSION: Changes in the composition of intestinal microbiota may be associated with indicators of an immunological challenge and may result in an increased health risk of mountaineers during exposure to very high altitude.

Abstract Transmissivity is often estimated from specific capacity data because of the expense of conducting standard aquifer tests to obtain transmissivity and the relative availability of specific capacity data. Most often, analytic expressions relating specific capacity to transmissivity derived by Thomasson and others (1960), Theis (1963), or Brown (1963) are used in this analysis. This paper focuses on a test of these relations using a large (215 pairs) data set from a heterogeneous aquifer. The analytic solutions predicting transmissivity from specific capacity do not agree well with the measured transmissivities, apparently due to turbulent well loss within the production wells, which is not taken into account by any of the analytic solutions. Empirical relations are better than the theoretical relations. Log‐log functions have greater correlation coefficients than linear functions. The best relation found for the data set chosen for this study has a correlation coefficient of 0.63, but the prediction interval was about 1.2 log cycles, indicating that the range of probable transmissivities corresponding to a single specific capacity was more than one order of magnitude. Tests with smaller subsets of data suggest that correlations based on data sets of 10 points or less are of limited value.

BACKGROUND: Diatoms are of great significance to primary productivity in oceans, yet little is known about their biogeographic distribution in oligotrophic rivers. RESULTS: With the help of metabarcoding analysis of 279 samples from the Yangtze River, we provided the first integral biogeographic pattern of planktonic and benthic diatoms over a 6030 km continuum along the world's third largest river. Our study revealed spatial dissimilarity of diatoms under varying landforms, including plateau, mountain, foothill, basin, foothill-mountain, and plain regions, from the river source to the estuary. Environmental drivers of diatom communities were interpreted in terms of photosynthetically active radiation, temperature, channel slope and nutrients, and human interference. Typical benthic diatoms, such as Pinnularia, Paralia, and Aulacoseira, experienced considerable reduction in relative abundance downstream of the Three Gorges Dam and the Xiluodu Dam, two of the world's largest dams. CONCLUSIONS: Our study revealed that benthic diatoms are of particular significance in characterizing motile guild in riverine environments, which provides insights into diatom biogeography and biogeochemical cycles in large river ecosystems.

Malingering occupies a range on a continuum from biased self-perception to conscious, deliberate, serious lies. One aspect of this continuum is the element of self-conscious or deliberate control. Suggestions from Darwin's writings concerning the role of voluntary and involuntary activation of the facial muscles are examined and illustrated with data from a 40 year program of research on deception. The impact of the voluntary-involuntary distinction on the appearance, timing, symmetry and cohesion of facial expressions of emotion is explained. Data relevant to changes in vocal and gestural aspects of demeanor in honest and deceptive behavior are also reviewed. The relevance of these laboratory-based findings on the voluntary control of nonverbal behavior in assessing some types of malingering is discussed.

Climate change and land-use/cover change (LUCC) are two major types of global environmental change. They are increasingly challenging the main objectives of ecosystem management, which are to provide ecosystem services sustainably to society and maintain biodiversity. However, a comprehensive understanding of how climate-land-use change affects these primary goals of ecosystem management is still lacking. Here, a global literature review on the impacts of climate change and LUCC on ecosystem services related to biodiversity is presented. In this review, possible ecological responses at species, community, and ecosystem levels, and the effects of interaction mechanisms between climate change and LUCC on biodiversity-related ecosystem services are identified. The results show possible effects on species facing climate change challenges through affecting distribution/range shifts, interspecific relations, richness, and abundance, and the impacts on biodiversity through increasing extinction rates, nutrient deposition, and habitat fragmentation under LUCC. Climate change may hinder the ability of species to deal with LUCC, and in turn LUCC could reduce resilience to climate change. Understanding of these interactions is necessary to address the increasing pressure on sustainable provisioning of ecosystem services under different climate and land-use scenarios in the future.

Zhu, C., Ma, C., Yu, S.‐Y., Tang, L., Zhang, W. & Lu, X. 2009: A detailed pollen record of vegetation and climate changes in Central China during the past 16 000 years. Boreas , 10.1111/j.1502‐3885.2009.00098.x. ISSN 0300‐9483. Detailed pollen analyses, along with magnetic and loss‐on‐ignition (LOI) measurements, were conducted on a 3 m long peat sequence recovered from the Dajiuhu Basin, the Shennongjia Mountains in Central China. Ten AMS 14 C dates provide a firm age control on this pollen record in terms of vegetation changes governed essentially by the rise and fall of the Asian summer monsoon during the past 16 000 years. Between 16 000 and 12 700 cal. yr BP, pollen assemblages were dominated by coniferous and broad‐leaved trees, indicating a mixed forest landscape corresponding to the initial establishment of the monsoonal climate after the Last Glaciation. The progressive increases in percentages of evergreen tree pollen after 12 700 cal. yr BP point to a steady enhancement of the summer monsoon, which was episodically weakened during the Younger Dryas stadial. From 11 000 to 6000 cal. yr BP, values of coniferous and deciduous tree pollen decreased, while evergreen broad‐leaved tree pollen increased substantially, implying a stronger than normal monsoonal climate condition corresponding to the Holocene Hypsithermal Interval. A great reduction in the values of evergreen tree pollen at about 4000 cal. yr BP indicates a sudden retreat of the summer monsoon from this area.

Abstract The use of surfactant solutions for the in situ recovery of residual NAPL in aquifers is increasingly considered as a viable remediation technique. The injection of a few pore volumes of high concentration surfactant solutions can mobilize most of the residual NAPL contacted by the solutions. However, the washing solutions’physico‐chemical properties (low density and high viscosity), combined with the natural porous media heterogeneity, can prevent a good sweep of the entire contaminated volume. From the petroleum industry, it is well‐known that polymer solutions can be injected following a surfactant solution slug to act as a mobility buffer and increase the overall sweep efficiency. The objective of our laboratory study is first to select and characterize polymers that would be suitable for aquifer restoration. Our experiments showed that among several polymers, xanthan gum solution rheology was made in order to predict shear rates, xanthan gum concentrations, salinity, and temperature effects on solution viscosity. The second set of experiments were made with a sand box which was designed to reproduce a simple heterogeneous media consisting of layers of sand with different permeability. These tests illustrate the xanthan gum solution's ability to increase surfactant solution's sweep efficiency and limit viscous fingering. The tests established that: (1) the injection of xanthan solution behind a surfactant solution slug decreases fluid velocity in high permeability layers and increases it in low‐permeability ones, thus increasing the sweep efficiency (2) xanthan solutions eliminate viscous fingering at the polymer/surfactant solution front; (3) a xanthan solution preflush is desirable to limit surfactant solution mobility and prevent surfactant adsorption on solids; and (4) depending on site heterogeneity injection strategies should be applied to limit overriding by low‐density surfactant solution.

This study investigated the environmental effects of two familiar emerging contaminants, sulfamethoxazole (SMX) and erythromycin (ERY), and their mixture (10:1 w/w) using a green microalga, R. subcapitata. The cell density, pigment content, and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) glutathione peroxidase (GSH-Px), and glutathione S-transferase (GST) were analyzed. The calculated EC50 values of SMX, ERY, and their mixture after 96 h were 0.49, 0.044, and 0.06 mg/L, respectively. High concentrations of antibiotics lead to a decrease in chlorophyll a and total carotenoid content, affecting the ability to photosynthesize ROS scavenging capacity. This may be a factor leading to the inhibition of algal growth. When R. subcapitata was exposed to SMX and the mixture, SOD and CAT increased to resist oxidative damage, while the activities of GSH and GST decreased, suggesting that this algae’s antioxidant system was unbalanced due to oxidative stress. R. subcapitata reduced the ERY-induced ROS by increasing the activities of SOD, GSH, and GST. The difference in the contents of nonenzymatic antioxidants and enzyme antioxidants in R. subcapitata indicated the antioxidant mechanisms to SMX and ERY were not identical. This study provides insights into the oxidative stress process in R. subcapitata under different antibiotics.

Abstract Under global warming, projected changes in precipitation have shown an asymmetrical shift from light to heavy precipitation over China. However, the role of urbanization in this shift remains unknown. Here, we show that increases in total rainy‐season (May‐September) precipitation over the Yangtze River Delta (YRD) urban agglomeration of East China are characterized by decreasing light precipitation and increasing heavy precipitation during 1961–2019. This asymmetrical shift toward heavier precipitation is even more prominent in urban than rural areas. Areas with faster urban expansion rates exhibit stronger negative (positive) trends in light (heavy) precipitation. Urbanization contributes to 44.4% (26.4%) of the decreasing (increasing) light (heavy) precipitation in the urban areas of the YRD. We suggest that urban managers should consider potential adverse impacts of this asymmetrical shift, which may favor increases in both the frequency of heatwaves and waterlogging.

Geothermal energy is a precious resource, which is widely distributed, varied, and abundant. China has entered a period of rapid development of geothermal energy since 2010. As shallow geothermal energy promoting, the depth of hydrothermal geothermal exploration is increasing. The quality of Hot Dry Rock (HDR) and related exploratory technologies are better developed and utilized. On the basis of geothermal development, this paper reviews the geothermal progress during the "12th Five-Year Plan", and summarizes the achievements of hydrothermal geothermal and hot dry rocks from geothermal survey and evaluation aspects. Finally, the authors predict the development trend of the future geothermal research to benefit geothermal and hot dry rock research.