Holocene moisture and East Asian summer monsoon evolution in the northeastern Tibetan Plateau recorded by Lake Qinghai and its environs: A review of conflicting proxies

NASA Astrophysics Data System (ADS)

Chen, Fahu; Wu, Duo; Chen, Jianhui; Zhou, Aifeng; Yu, Junqing; Shen, Ji; Wang, Sumin; Huang, Xiaozhong

2016-12-01

Climatic and environmental changes in the northeastern Tibetan Plateau are controlled by the Asian summer monsoon (ASM) and the westerlies, two key circulation components of the global climate system which directly affect a large human population and associated ecosystems in eastern Asia. During the past few decades, a series of Holocene palaeoclimatic records have been obtained from sediment cores from Lake Qinghai and from various other geological archives in the surrounding area of the northeastern Tibetan Plateau. However, because of uncertainties regarding the sediment chronologies and the climatic significance of the proxies used, the nature of Holocene climatic changes in the region remains unclear and even controversial. Here we review all major classes of the published data from drilled cores from Lake Qinghai, as well as other evidence from lakes and aeolian deposits from surrounding areas, in order to reconstruct changes in moisture patterns and possible summer monsoon evolution in the area during the Holocene. Combining the results of moisture and precipitation proxies such as vegetation history, pollen-based precipitation reconstruction, aeolian activity, lake water depth/lake level changes, salinity and sediment redness, we conclude that moisture and precipitation began to increase in the early Holocene, reached their maximum during the middle Holocene, and decreased during the late Holocene - similar to the pattern of the East Asian summer monsoon (EASM) in northern China. It is clear that the region experienced a relatively dry climate and weak EASM during the early Holocene, as indicated by relatively low tree pollen percentages and fluctuating pollen concentrations; generally low lake levels of Lake Qinghai and the adjacent Lake Hurleg and Lake Toson in the Qaidam Basin; and widely distributed aeolian sand deposition in the Lake Qinghai Basin and the nearby Gonghe Basin to the south, and in the eastern Qaidam Basin to the west. We argue that the

Highly Pathogenic Avian Influenza A(H5N8) Virus in Wild Migratory Birds, Qinghai Lake, China.

PubMed

Li, Mingxin; Liu, Haizhou; Bi, Yuhai; Sun, Jianqing; Wong, Gary; Liu, Di; Li, Laixing; Liu, Juxiang; Chen, Quanjiao; Wang, Hanzhong; He, Yubang; Shi, Weifeng; Gao, George F; Chen, Jianjun

2017-04-01

In May 2016, a highly pathogenic avian influenza A(H5N8) virus strain caused deaths among 3 species of wild migratory birds in Qinghai Lake, China. Genetic analysis showed that the novel reassortant virus belongs to group B H5N8 viruses and that the reassortment events likely occurred in early 2016.

Holocene record of eolian activity from Genggahai Lake, northeastern Qinghai-Tibetan Plateau, China

NASA Astrophysics Data System (ADS)

Qiang, Mingrui; Liu, Yingying; Jin, Yanxiang; Song, Lei; Huang, Xiangtong; Chen, Fahu

2014-01-01

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.

Prehistoric Human Adaptation to Tibetan Plateau Environment indicated by 151 site in the Qinghai Lake Basin

NASA Astrophysics Data System (ADS)

Zhang, Dongju; Dong, Guanghui; Wang, Qianqian; Ren, Xiaoyan; Chen, Fahu

2017-04-01

Current study indicates that Northeastern Tibetan Plateau (NETP) is one of the first widely occupied places by prehistory people on the Tibetan Plateau, which makes NETP very important to understand the human history on the plateau and human adaptation to high elevation environment. Hence, 151 site, a paleo- to Epi-Paleolithic site in the Qinghai Lake basin on NETP, is chosen to excavate. Thousands pieces of animal bones, hundreds pieces of stone artifacts and several possible hearths were unearthed and obtained during two excavation seasons. Carefully redating of the site shows that it was first occupied shortly around 15 ka BP, then reoccupied from 9000-6000 a BP more intensely. Preliminary study of the site suggest that the first appearance of human in Qinghai Lake basin is closely related to the amelioration of the Last Deglaciation and the prevalence of microlithic technology in North China, which may enlighten the study of early human migration on to whole plateau; however, the latter more intense human occupation in 151 site is not only closely related to the warm and stable early-mid Holocene climate but also provoked by early millet agriculture in neighbor low-elevation Loess plateau.

Taxonomic and Functional Differences between Microbial Communities in Qinghai Lake and Its Input Streams

PubMed Central

Ren, Ze; Wang, Fang; Qu, Xiaodong; Elser, James J.; Liu, Yang; Chu, Limin

2017-01-01

Understanding microbial communities in terms of taxon and function is essential to decipher the biogeochemical cycling in aquatic ecosystems. Lakes and their input streams are highly linked. However, the differences between microbial assemblages in streams and lakes are still unclear. In this study, we conducted an intensive field sampling of microbial communities from lake water and stream biofilms in the Qinghai Lake watershed, the largest lake in China. We determined bacterial communities using high-throughput 16S rRNA gene sequencing and predicted functional profiles using PICRUSt to determine the taxonomic and functional differences between microbial communities in stream biofilms and lake water. The results showed that stream biofilms and lake water harbored distinct microbial communities. The microbial communities were different taxonomically and functionally between stream and lake. Moreover, streams biofilms had a microbial network with higher connectivity and modularity than lake water. Functional beta diversity was strongly correlated with taxonomic beta diversity in both the stream and lake microbial communities. Lake microbial assemblages displayed greater predicted metabolic potentials of many metabolism pathways while the microbial assemblages in stream biofilms were more abundant in xenobiotic biodegradation and metabolism and lipid metabolism. Furthermore, lake microbial assemblages had stronger predicted metabolic potentials in amino acid metabolism, carbon fixation, and photosynthesis while stream microbial assemblages were higher in carbohydrate metabolism, oxidative phosphorylation, and nitrogen metabolism. This study adds to our knowledge of stream-lake linkages from the functional and taxonomic composition of microbial assemblages. PMID:29213266

Wetland evolution in the Qinghai Lake area, China, in response to hydrodynamic and eolian processes during the past 1100 years

NASA Astrophysics Data System (ADS)

Yan, Dada; Wünnemann, Bernd; Hu, Yanbo; Frenzel, Peter; Zhang, Yongzhan; Chen, Kelong

2017-04-01

The Daotanghe riverine wetland in close proximity to the Qinghai Lake was investigated to demonstrate the interrelationships between Qinghai Lake hydrodynamic processes, eolian mobility and ecological conditions during the past 1100 years in response to climate change. We used ostracod assemblages from various sites east of Qinghai Lake and from the sediment core QW15 of Daotanghe Pond and combined them with grain size and geochemical data from the same core. The statistical extraction of grain size endmembers (EM) revealed three different transportation processes responsible for pond-related fluvio-lacustrine, pure fluvial and eolian deposits. Identified seasonal effects (eolian mobility phase) and timing of ice cover are possible tracers for the competing influence between the Asian summer monsoon and the Westerlies in the Daotanghe Wetland and surrounding area. Our results show that ostracod associations and sediment properties are evidence of a fluvio-lacustrine fresh water environment without ingression of Qinghai Lake into the wetland. Hydrodynamic variations coupled with phases of eolian input indicate highly variable water budgets in response to climate-induced effective moisture supply. The Medieval Warm Period (MWP) until about 1270 CE displays generally moist and warm climate conditions with minor fluctuations, likely in response to variations in summer monsoon intensity. The three-partite period of the Little Ice Age (LIA), shows hydrologically unstable conditions between 1350 and 1530 CE with remarkably colder periods, assigned to a prolonged seasonal ice cover. Pond desiccation and replacement by fluvial deposits occurred between 1530 and 1750 CE, superimposed by eolian deposits. The phase 1730-1900 CE is recorded by the re-occurrence of a pond environment with reduced eolian input. Principal Component Analysis (PCA) on ostracod abundances shows similar trends. All three phases of the LIA developed during a weak summer monsoon influence, favoring

Study on the relationship between the lake area variations of Qinghai-Tibetan Plateau and the corresponding climate change in their basins

NASA Astrophysics Data System (ADS)

Guozhuang, Shen; Jingjuan, Liao; Huadong, Guo; Yingkui, Li

2014-03-01

Qinghai-Tibetan Plateau is the largest lake area in China, with a total area of existing lakes of 36,900km2, accounting for 52% of the total lake area of China. Lakes on the Tibetan Plateau play critical roles in the water cycle and ecological and environment systems of the Plateau. The global trend of warming up is increasing obviously, which has led to major changes in the climate conditions in China, even in the world. Whereas, when they analyse the relationship they just use the weather station's recording data, without any spatial analysis of the climate data. Here, we will do some researches on the relationship between the 10 selected lakes' area variation and the corresponding climate change in their drainage basin and discuss how the lakes changes in recent 40 years using the climate data processed using the spatial kriging. Thus, the drainage area can be taken into account and a real relationship can be pointed out. In order to study the relationship, Landsat MSS data, Landsat TM, Landsat ETM images, the topographic map have been collected to extract the variation of lake area. The 131 weather stations climate data, including precipitation, temperature, sun shine duration, evaporation are chosen to study the relationship. After extraction of the area of the lakes, a multivariate statistical analysis method was used to test the relationship between the area of the lakes and the global climate change, including the change of the temperature, the precipitation, and other factors. The variation of lakes in Qinghai-Tibetan Plateau is related to the mean temperature, the precipitation and saturation vapour pressure. But the frozen soil may affect the lake area variation to some extent.

Summer moisture changes in the Lake Qinghai area on the northeastern Tibetan Plateau recorded from a meadow section over the past 8400 yrs

NASA Astrophysics Data System (ADS)

Li, Xiangzhong; Liu, Xiangjun; He, Yuxin; Liu, Weiguo; Zhou, Xin; Wang, Zheng

2018-02-01

Holocene climatic and environmental changes on the northeastern Tibetan Plateau (TP) have been widely discussed based on the climatic records from sedimentary cores. However, differences in the reconstructed climatic history from various studies in this region still exist, probably due to influence of climatic proxies from multiple factors and the chronological uncertainties in lacustrine sediments. Here we present records of terrestrial plant δ13C, soil color and total organic carbon content over the past 8400 years from a well-dated meadow section on the northeastern TP. The terrestrial plant δ13C value serves as a good summer precipitation/moisture indicator in the studied region. Soil color property and TOC content are also able to disentangle the moisture evolution history. All the data show much wet climates at 8400-7400 cal yr BP, dry climates at 7400-6000 cal yr BP and then wet conditions with fluctuation at 6000-3200 cal yr BP. Late Holocene moisture appears to be comparable with moist conditions from 6000 to 3200 cal yr BP. By further comparing the climatic variations in the Lake Qinghai area with records of the reconstructed summer temperature and the Asian Monsoon precipitation, we believe that the pattern of moisture/precipitation evolution in the Lake Qinghai area was not completely consistent with regions around Lake Qinghai, probably due to complicated interaction between the East Asian Summer Monsoon and the Indian Summer Monsoon.

Impact of a thermokarst lake on the soil hydrological properties in permafrost regions of the Qinghai-Tibet Plateau, China.

PubMed

Gao, Zeyong; Niu, Fujun; Wang, Yibo; Luo, Jing; Lin, Zhanju

2017-01-01

The formation of thermokarst lakes can degrade alpine meadow ecosystems through changes in soil water and heat properties, which might have an effect on the regional surface water and groundwater processes. In this study, a typical thermokarst lake was selected in the Qinghai-Tibet Plateau (QTP), and the ecological index (S L ) was used to divide the affected areas into extremely affected, severely affected, medium-affected, lightly affected, and non-affected areas, and soil hydrological properties, including saturated hydraulic conductivity and soil water-holding capacity, were investigated. The results showed that the formation of a thermokarst lake can lead to the degradation of alpine meadows, accompanied by a change in the soil physiochemical and hydrological properties. Specifically, the soil structure turned towards loose soil and the soil nutrients decreased from non-affected areas to severely affected areas, but the soil organic matter and available potassium increased slightly in the extremely affected areas. Soil saturated hydraulic conductivity showed a 1.7- to 4.1-fold increase in the lake-surrounding areas, and the highest value (401.9cmd -1 ) was detected in the severely affected area. Soil water-holding capacity decreased gradually during the transition from the non-affected areas to the severely affected areas, but it increased slightly in the extremely affected areas. The principal component analysis showed that the plant biomass was vital to the changes in soil hydrological properties. Thus, the vegetation might serve as a link between the thermokarst lake and soil hydrological properties. In this particular case, it was concluded that the thermokarst lake adversely affected the regional hydrological services in the alpine ecosystem. These results would be useful for describing appropriate hydraulic parameters with the purpose of modeling soil water transportation more accurately in the Qinghai-Tibet Plateau. Copyright © 2016 Elsevier B.V. All

Late Pleistocene paleoclimatic history documented by an oxygen isotope record from carbonate sediments in Qarhan Salt Lake, NE Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Fan, QiShun; Ma, HaiZhou; Wei, HaiCheng; Shan, FaShou; An, FuYuan; Xu, LiMing; Madsen, David B.

2014-05-01

Late Pleistocene paleoclimatic variability on the northeastern Qinghai-Tibetan Plateau (NE QTP) was reconstructed using a chronology based on AMS 14C and 230Th dating results and a stable oxygen isotopic record. These are derived from lake carbonates in a 102-m-long Qarhan sediment core (ISL1A) collected from the eastern Qaidam Basin. Previous research indicates that the δ18O values of lacustrine carbonates are mainly controlled by the isotopic composition of lake water, which in turn is a function of regional P/E balance and the proportion of precipitation that is monsoon-derived on the NE QTP. Modern isotopic observations indicate that the δ18O values of lake carbonates in hyper-arid Qaidam Basin are more positive during the warm and wet period. Due to strong evaporation and continental effect in this basin, the positive δ18O values in the arid region indicate drier climatic conditions. Based on this interpretation and the δ18O record of fine-grained lake carbonates and dating results in ISL1A, the results imply that drier climatic conditions in the Qarhan region occurred in three intervals, around 90-80 ka, 52-38 ka and 10-9 ka, which could correspond to late MIS 5, middle MIS 3 and early Holocene, respectively. These three phases were almost coincided with low lake level periods of Gahai, Toson and Qinghai Lakes (to the east of Qarhan Lake) influenced by ASM on the orbital timescales. Meanwhile, there was an episode of relatively high δ18O value during late MIS 3, suggesting that relatively dry climatic condition in this period, rather than “a uniform Qarhan mega-paleolake” spanning the ˜44 to 22 ka period. These results insight into the understanding of “the Greatest Lake Period” on the QTP.

Salinity shapes microbial diversity and community structure in surface sediments of the Qinghai-Tibetan Lakes.

PubMed

Yang, Jian; Ma, Li'an; Jiang, Hongchen; Wu, Geng; Dong, Hailiang

2016-04-26

Investigating microbial response to environmental variables is of great importance for understanding of microbial acclimatization and evolution in natural environments. However, little is known about how microbial communities responded to environmental factors (e.g. salinity, geographic distance) in lake surface sediments of the Qinghai-Tibetan Plateau (QTP). In this study, microbial diversity and community structure in the surface sediments of nine lakes on the QTP were investigated by using the Illumina Miseq sequencing technique and the resulting microbial data were statistically analyzed in combination with environmental variables. The results showed total microbial community of the studied lakes was significantly correlated (r = 0.631, P < 0.001) with lake salinity instead of geographic distance. This suggests that lake salinity is more important than geographic distance in shaping the microbial diversity and community structure in the studied samples. In addition, the abundant and rare taxa (OTUs with relative abundance higher than 1% and lower than 0.01% within one sample, respectively) were significantly (P < 0.05) correlated (r = 0.427 and 0.783, respectively) with salinity, suggesting rare taxa might be more sensitive to salinity than their abundant counterparts, thus cautions should be taken in future when evaluating microbial response (abundant vs. rare sub-communities) to environmental conditions.

The aliphatic hydrocarbon distributions of terrestrial plants around an alpine lake: a pilot study from Lake Ximencuo, Eastern Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

Pu, Yang; Jia, Jihong; Cao, Jicheng

2017-12-01

As part of an investigation of the sources of aliphatic hydrocarbons to the sediments of alpine Lake Ximencuo, leaves of the eight dominant vascular plants were collected and their hydrocarbon contents were analyzed. A series of unsaturated aliphatic hydrocarbons were identified in the plant leaves; in particular, Festuca sp. contain a series of n-alkadienes that have rarely been reported in previous studies. The comparison of n-alkane proxies (ACL 27-33, ACL T, P aq, and CPI) and δ13Corg among plant leaves, surface soils, and lake sediments suggests that organic proxies have been altered to varying degrees during the transport and burial process of organic materials. It is believed that microbial reworking and source changes have great impacts on organic proxies in the alpine lake system. In addition, the cluster analysis for plant leaves depending on n-alkane compositions and the ACL T proxy generates similar results. Accordingly, we postulate that the average chain length of plant waxes might be a potential indicator of plant classification in regions such as the Qinghai-Tibet Plateau.

Evaluation of thermokarst lake water balance in the Qinghai-Tibet Plateau via isotope tracers.

PubMed

Gao, Zeyong; Niu, Fujun; Lin, Zhanju; Luo, Jing; Yin, Guoan; Wang, Yibo

2018-04-24

Thermokarst lakes are a ubiquitous landscape feature, which widely distributed in the pan-arctic and some low latitude regions, and are associated with regional hydrological processes. The studies were taken to obtain a better understanding of the water balance of thermokarst lakes in the Qinghai-Tibet Plateau (QTP) in order to gain insight of the regional hydrological cycle. The characteristics of the stable isotopes δ 18 O and δ D were investigated in precipitation, permafrost meltwater, and thermokarst lake water in the continuous permafrost region of the QTP and analyzed the lake water balance using the isotope mass model. The results showed that the δ D-δ 18 O relationship in the thermokarst lakes (δ D = 5.45 δ 18 O - 18.95) differed from that of the local precipitation (δ D = 8.30 δ 18 O + 18.49) and permafrost meltwater (δ D = 5.78 δ 18 O - 23.41), and the mean isotope compositions in the thermokarst lakes were -7.2‰ in δ 18 O and -58.0‰ in δ D. The more positive isotope signals in thermokarst lakes than in the precipitation and permafrost meltwater revealed that the lakes had experienced stronger isotope enrichment. Additionally, the evaporation-to-inflow ratio (E/I) values were < 1 in most of the thermokarst lakes (84%), which might be explained by the recent expansion of the lake surfaces. However, 16% of the thermokarst lakes had shrunk, owing to thermokarst erosion, lateral expansion as the temperature increases, and lower recharge volume. Moreover, precipitation on the lake surface was only 14-18% of the inflow volume in the thermokarst lakes, and the surface-subsurface inflow and permafrost meltwater are very important for recharging the lakes and maintaining the water balance. The results of this study provide a comprehensive understanding of the influence of climate warming on hydrological processes in the permafrost regions in the QTP. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of the Qinghai-Tibet Railway on the Landscape Genetics of the Endangered Przewalski's Gazelle (Procapra przewalskii).

PubMed

Yu, He; Song, Shiya; Liu, Jiazi; Li, Sheng; Zhang, Lu; Wang, Dajun; Luo, Shu-Jin

2017-12-21

The Przewalski's gazelle (Procapra przewalskii) is one of the most endangered ungulates in the world, with fewer than 2,000 individuals surviving in nine habitat fragments on the Qinghai-Tibet Plateau and isolated by human settlements and infrastructure. In particular, the Qinghai-Tibet railway, which crosses the largest part of the gazelle's distribution, remains a major concern because of its potential to intensify landscape genetic differentiation. Here, using mtDNA sequencing and microsatellite genotyping to analyze 275 Przewalski's gazelle samples collected throughout the range, we observed low level of genetic diversity (mtDNA π = 0.0033) and strong phylogeographic structure. Overall, the nine patches of gazelles can be further clustered into five populations, with a strong division between the eastern vs. western side of Qinghai Lake. Our study provides the first evidence of the genetic divergence between the Haergai North and Haergai South gazelle populations, corresponding to the recent construction of a wired enclosure along the Qinghai-Tibet railway less than ten years ago, an equivalent of five generations. Well-designed wildlife corridors across the railway along with long-term monitoring of the anthropogenic effects are therefore recommended to alleviate further habitat fragmentation and loss of genetic diversity in Przewalski's gazelle.

Wild Bird Migration across the Qinghai-Tibetan Plateau: A Transmission Route for Highly Pathogenic H5N1

PubMed Central

Prosser, Diann J.; Cui, Peng; Takekawa, John Y.; Tang, Mingjie; Hou, Yuansheng; Collins, Bridget M.; Yan, Baoping; Hill, Nichola J.; Li, Tianxian; Li, Yongdong; Lei, Fumin; Guo, Shan; Xing, Zhi; He, Yubang; Zhou, Yuanchun; Douglas, David C.; Perry, William M.; Newman, Scott H.

2011-01-01

Background Qinghai Lake in central China has been at the center of debate on whether wild birds play a role in circulation of highly pathogenic avian influenza virus H5N1. In 2005, an unprecedented epizootic at Qinghai Lake killed more than 6000 migratory birds including over 3000 bar-headed geese (Anser indicus). H5N1 subsequently spread to Europe and Africa, and in following years has re-emerged in wild birds along the Central Asia flyway several times. Methodology/Principal Findings To better understand the potential involvement of wild birds in the spread of H5N1, we studied the movements of bar-headed geese marked with GPS satellite transmitters at Qinghai Lake in relation to virus outbreaks and disease risk factors. We discovered a previously undocumented migratory pathway between Qinghai Lake and the Lhasa Valley of Tibet where 93% of the 29 marked geese overwintered. From 2003–2009, sixteen outbreaks in poultry or wild birds were confirmed on the Qinghai-Tibet Plateau, and the majority were located within the migratory pathway of the geese. Spatial and temporal concordance between goose movements and three potential H5N1 virus sources (poultry farms, a captive bar-headed goose facility, and H5N1 outbreak locations) indicated ample opportunities existed for virus spillover and infection of migratory geese on the wintering grounds. Their potential as a vector of H5N1 was supported by rapid migration movements of some geese and genetic relatedness of H5N1 virus isolated from geese in Tibet and Qinghai Lake. Conclusions/Significance This is the first study to compare phylogenetics of the virus with spatial ecology of its host, and the combined results suggest that wild birds play a role in the spread of H5N1 in this region. However, the strength of the evidence would be improved with additional sequences from both poultry and wild birds on the Qinghai-Tibet Plateau where H5N1 has a clear stronghold. PMID:21408010

Wild bird migration across the Qinghai-Tibetan plateau: a transmission route for highly pathogenic H5N1.

PubMed

Prosser, Diann J; Cui, Peng; Takekawa, John Y; Tang, Mingjie; Hou, Yuansheng; Collins, Bridget M; Yan, Baoping; Hill, Nichola J; Li, Tianxian; Li, Yongdong; Lei, Fumin; Guo, Shan; Xing, Zhi; He, Yubang; Zhou, Yuanchun; Douglas, David C; Perry, William M; Newman, Scott H

2011-03-09

Qinghai Lake in central China has been at the center of debate on whether wild birds play a role in circulation of highly pathogenic avian influenza virus H5N1. In 2005, an unprecedented epizootic at Qinghai Lake killed more than 6000 migratory birds including over 3000 bar-headed geese (Anser indicus). H5N1 subsequently spread to Europe and Africa, and in following years has re-emerged in wild birds along the Central Asia flyway several times. To better understand the potential involvement of wild birds in the spread of H5N1, we studied the movements of bar-headed geese marked with GPS satellite transmitters at Qinghai Lake in relation to virus outbreaks and disease risk factors. We discovered a previously undocumented migratory pathway between Qinghai Lake and the Lhasa Valley of Tibet where 93% of the 29 marked geese overwintered. From 2003-2009, sixteen outbreaks in poultry or wild birds were confirmed on the Qinghai-Tibet Plateau, and the majority were located within the migratory pathway of the geese. Spatial and temporal concordance between goose movements and three potential H5N1 virus sources (poultry farms, a captive bar-headed goose facility, and H5N1 outbreak locations) indicated ample opportunities existed for virus spillover and infection of migratory geese on the wintering grounds. Their potential as a vector of H5N1 was supported by rapid migration movements of some geese and genetic relatedness of H5N1 virus isolated from geese in Tibet and Qinghai Lake. This is the first study to compare phylogenetics of the virus with spatial ecology of its host, and the combined results suggest that wild birds play a role in the spread of H5N1 in this region. However, the strength of the evidence would be improved with additional sequences from both poultry and wild birds on the Qinghai-Tibet Plateau where H5N1 has a clear stronghold.

Monitoring the lake area changes of the Qinghai-Tibet Plateau using coarse-resolution time series remote sensing data

NASA Astrophysics Data System (ADS)

Ma, M.

2015-12-01

The Qinghai-Tibet Plateau (QTP) is the world's highest and largest plateau and is occasionally referred to as "the roof of the world". As the important "water tower", there are 1,091 lakes of more than 1.0 km2 in the QTP areas, which account for 49.4% of the total area of lakes in China. Some studies focus on the lake area changes of the QTP areas, which mainly use the middle-resolution remote sensing data (e.g. Landsat TM). In this study, the coarse-resolution time series remote sensing data, MODIS data at a spatial resolution of 250m, was used to monitor the lake area changes of the QTP areas during the last 15 years. The dataset is the MOD13Q1 and the Normal Difference Vegetation Index (NDVI) is used to identify the lake area when the NDVI is less than 0. The results show the obvious inner-annual changes of most of the lakes. Therefore the annually average and maximum lake areas are calculated based on the time series remote data, which can better quantify the change characteristics than the single scene of image data from the middle-resolution data. The results indicate that there are big spatial variances of the lake area changes in the QTB. The natural driving factors are analyzed for revealing the causes of changes.

Atmospheric oxalic acid and related secondary organic aerosols in Qinghai Lake, a continental background site in Tibet Plateau

NASA Astrophysics Data System (ADS)

Meng, Jingjing; Wang, Gehui; Li, Jianjun; Cheng, Chunlei; Cao, Junji

2013-11-01

Summertime PM2.5 aerosols collected from Qinghai Lake (3200 m a.s.l.), a remote continental site in the northeastern part of Tibetan Plateau, were analyzed for dicarboxylic acids (C2-C11), ketocarboxylic acids and α-dicarbonyals. Oxalic acid (C2) is the dominant dicarboxylic acid in the samples, followed by malonic, succinic and azelaic acids. Total dicarboxylic acids (231 ± 119 ng m-3), ketocarboxylic acids (8.4 ± 4.3 ng m-3), and α-dicarbonyls (2.7 ± 2.1 ng m-3) at the Tibetan background site are 2-5 times less than those detected in lowland areas such as 14 Chinese megacities. Compared to those in other urban and marine areas enhancements in relative abundances of C2/total diacids and diacids-C/WSOC of the PM2.5 samples suggest that organic aerosols in the region are more oxidized due to strong solar radiation. Molecular compositions and air mass trajectories demonstrate that the above secondary organic aerosols in the Qinghai Lake atmosphere are largely derived from long-range transport. Ratios of oxalic acid, glyoxal and methylglyoxal to levoglucosan in PM2.5 aerosols emitted from household burning of yak dung, a major energy source for Tibetan in the region, are 30-400 times lower than those in the ambient air, which further indicates that primary emission from biomass burning is a negligible source of atmospheric oxalic acid and α-dicarbonyls at this background site.

Radiocarbon reservoir between charred seeds and fish bone in Neolithic sites, northeastern Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Zhou, A.; Dong, G.; Ren, L.

2017-12-01

Many efforts have been done to understand the reservoir effect of Qinghai Lake, yet no agreement has been reached. Five archaeological sites, located around the junction between the estuary of Rivers and Qinghai Lake, are the earliest Neolithic Age sites in the Qinghai- Tibetan Plateau (QTP), which is critical for understanding patterns of prehistoric human inhabitation in the high plateau extreme environments. This study compares radiocarbon dates of fish bones and terrestrial plant remains uncovered from the same archaeological strata to see whether there was reservoir effect reference to reliable data. Results demonstrate that there were reservoir effects ranging from 300 to 600 years back to 3600 years ago, nevertheless, no reservoir was observed of the modern fish. Besides, stable isotopic analysis illustrated that modern fish consumed similar food to those of millennias ago.

Alkenone temperature and salinity: An evaluation of long chain C37 alkenone in Lake Qinghai, China

NASA Astrophysics Data System (ADS)

Liu, W.; Liu, Z.; Fu, M.; An, Z.

2007-12-01

In recently years, the alkenone unsaturation index (Uk'37=C37:.2/(C37:2+ C37:3)) has been used to reconstructed paleo-temperature for lacustrine sediments. However, few studies have addressed whether the relative abundance of the C37:4 alkenone to the total C37 production (C37:4 percent) can reflect surface salinity changes in lake systems. Here we present the distribution of C37 long chain alkenone of modern lake sediments in Qinghai Lake, Qing-Tibet Plateau, to evaluate significance of abundance change of long chain C37 alkenone as an indicator of lake paleo-enviromental evolution. A group of surface sediments from different locations in the lake have been analyzed in this study. The results of long chain C37 alkenone from 28 surface sediments analyses shown relative abundance of C37:4 alkenone to total C37 production (C37:4 percent) change from 14.5 to 48.6 percent and the abundance of C37:4 alkenone is increasing with decreasing salinity of lake water. For the salinity lake in land, we suggested the relative abundance of C37:4 alkenone in lake sediments may be a indicator of paleo-silinity; We have also found that Uk'37 values are weakly correlated with salinity and C37:4 percent changes, implying that potential minor contributions of temperature and salinity effects to C37:4 percent and Uk'37 respectively cannot be excluded in this study. However, since these contributions are weak, we suggest that the C37:4 percent proxy can be used to reconstruct paleo-salinity changes at a regional scale, especially in lake systems, while Uk'37 remains as a powerful tool for reconstructions of paleo-temperature changes in the lake systems.

Hydrochemistry and controlling mechanism of lakes in permafrost regions along the Qinghai-Tibet Engineering Corridor, China

NASA Astrophysics Data System (ADS)

Gao, Zeyong; Lin, Zhanju; Niu, Fujun; Luo, Jing; Liu, Minghao; Yin, Guoan

2017-11-01

Lakes are the main water resource for migrating animals and herdsmen in permafrost regions along the Qinghai-Tibet Engineering Corridor (QTEC) and play a crucial role in regulating the balance between regional surface water and groundwater. Hydrochemical properties also affect the soil environment, ecological conditions, and hydrological cycle. In this study, 127 water samples were collected from lakes to analyze hydrochemistry characteristics. The results are discussed in the context of relationships between water chemistry and local conditions including climate, topography, and geology. The results showed that 43.3% of lakes are fresh, 19.7% are brackish, 18.9% are saline, 17.3% are brine, and only 0.8% are bitter. The dominant cation is Na+, followed by Mg2 +, Ca2 +, and K+. The dominant anion is Cl-, followed by SO42 - and HCO3- in the northern section of study region; whereas Ca2 +, Na+, and HCO3- are the dominant ions in the lakes of the southern section. The higher concentrations of carbonate in the southern lakes reflect contributions from groundwater discharge. In contrast, the higher concentrations of sodium, chloride, and sulfate in the northern section indicate that they are dominated by the interaction of evaporates. Additionally, cation exchange, precipitation, and dissolution have also modified the distribution of hydrochemical compositions. Thermokarst processes, in particular, have induced changes in the hydrochemistry of lake waters in the permafrost regions of the QTEC, in that the ion concentrations are closely related to ground ice content. In the context of persistent climatic warming and steadily increasing anthropogenic activities, the salinity of lakes along the QTEC is likely to increase in the future.

A multi-characteristic based algorithm for classifying vegetation in a plateau area: Qinghai Lake watershed, northwestern China

NASA Astrophysics Data System (ADS)

Ma, Weiwei; Gong, Cailan; Hu, Yong; Li, Long; Meng, Peng

2015-10-01

Remote sensing technology has been broadly recognized for its convenience and efficiency in mapping vegetation, particularly in high-altitude and inaccessible areas where there are lack of in-situ observations. In this study, Landsat Thematic Mapper (TM) images and Chinese environmental mitigation satellite CCD sensor (HJ-1 CCD) images, both of which are at 30m spatial resolution were employed for identifying and monitoring of vegetation types in a area of Western China——Qinghai Lake Watershed(QHLW). A decision classification tree (DCT) algorithm using multi-characteristic including seasonal TM/HJ-1 CCD time series data combined with digital elevation models (DEMs) dataset, and a supervised maximum likelihood classification (MLC) algorithm with single-data TM image were applied vegetation classification. Accuracy of the two algorithms was assessed using field observation data. Based on produced vegetation classification maps, it was found that the DCT using multi-season data and geomorphologic parameters was superior to the MLC algorithm using single-data image, improving the overall accuracy by 11.86% at second class level and significantly reducing the "salt and pepper" noise. The DCT algorithm applied to TM /HJ-1 CCD time series data geomorphologic parameters appeared as a valuable and reliable tool for monitoring vegetation at first class level (5 vegetation classes) and second class level(8 vegetation subclasses). The DCT algorithm using multi-characteristic might provide a theoretical basis and general approach to automatic extraction of vegetation types from remote sensing imagery over plateau areas.

Benthic Algal Community Structures and Their Response to Geographic Distance and Environmental Variables in the Qinghai-Tibetan Lakes With Different Salinity

PubMed Central

Yang, Jian; Jiang, Hongchen; Liu, Wen; Wang, Beichen

2018-01-01

Uncovering the limiting factors for benthic algal distributions in lakes is of great importance to understanding of their role in global carbon cycling. However, limited is known about the benthic algal community distribution and how they are influenced by geographic distance and environmental variables in alpine lakes. Here, we investigated the benthic algal community compositions in the surface sediments of six lakes on the Qinghai-Tibetan Plateau (QTP), China (salinity ranging from 0.8 to 365.6 g/L; pairwise geographic distance among the studied lakes ranging 8–514 km) employing an integrated approach including Illumina-Miseq sequencing and environmental geochemistry. The results showed that the algal communities of the studied samples were mainly composed of orders of Bacillariales, Ceramiales, Naviculales, Oscillatoriales, Spirulinales, Synechococcales, and Vaucheriales. The benthic algal community compositions in these QTP lakes were significantly (p < 0.05) correlated with many environmental (e.g., dissolved inorganic and organic carbon, illumination intensity, total nitrogen and phosphorus, turbidity and water temperature) and spatial factors, and salinity did not show significant influence on the benthic algal community structures in the studied lakes. Furthermore, geographic distance showed strong, significant correlation (r = 0.578, p < 0.001) with the benthic algal community compositions among the studied lakes, suggesting that spatial factors may play important roles in influencing the benthic algal distribution. These results expand our current knowledge on the influencing factors for the distributions of benthic alga in alpine lakes. PMID:29636745

Winter diet of lake herring (Coregonus artedi) in western Lake Superior

USGS Publications Warehouse

Link, Jason; Selgeby, James H.; Hoff, Michael H.; Haskell, Craig

1995-01-01

Lake herring (Coregonus artedi) and zooplankton samples were simultaneously collected through the ice in the Apostle Islands region of western Lake Superior to provide information on the winter feeding ecology of lake herring. Zooplankton constituted the entire diet of the 38 lake herring collected for this study. We found no evidence of piscivory, although it has been reported by anglers. Diet selectivities were calculated using a Wilcoxon signed-ranks test and showed a preference of lake herring for larger zooplankton, especially Diaptomus sicilis, whereas the smaller copepod,Cyclops bicuspidatus thomasi, and immature copepod stages were selected against. These data document that overwintering copepods are food for a broad size range of lake herring in winter.

Extent of Pleistocene lakes in the western Great Basin

USGS Publications Warehouse

Reheis, Marith C.

1999-01-01

During the Pliocene to middle Pleistocene, pluvial lakes in the western Great Basin repeatedly rose to levels much higher than those of the well-documented late Pleistocene pluvial lakes, and some presently isolated basins were connected. Sedimentologic, geomorphic, and chronologic evidence at sites shown on the map indicates that Lakes Lahontan and Columbus-Rennie were as much as 70 m higher in the early-middle Pleistocene than during their late Pleistocene high stands. Lake Lahontan at its 1400-m shoreline level would submerge present-day Reno, Carson City, and Battle Mountain, and would flood other now-dry basins. To the east, Lakes Jonathan (new name), Diamond, Newark, and Hubbs also reached high stands during the early-middle(?) Pleistocene that were 25-40 m above their late Pleistocene shorelines; at these very high levels, the lakes became temporarily or permanently tributary to the Humboldt River and hence to Lake Lahontan. Such a temporary connection could have permitted fish to migrate from the Humboldt River southward into the presently isolated Newark Valley and from Lake Lahontan into Fairview Valley. The timing of drainage integration also provides suggested maximum ages for fish to populate the basins of Lake Diamond and Lake Jonathan. Reconstructing and dating these lake levels also has important implications for paleoclimate, tectonics, and drainage evolution in the western Great Basin. For example, shorelines in several basins form a stair-step sequence downward with time from the highest levels, thought to have formed at about 650 ka, to the lowest, formed during the late Pleistocene. This descending sequence indicates progressive drying of pluvial periods, possibly caused by uplift of the Sierra Nevada and other western ranges relative to the western Great Basin. However, these effects cannot account for the extremely high lake levels during the early middle Pleistocene; rather, these high levels were probably due to a combination of increased

Interplay between the Westerlies and Asian monsoon recorded in Lake Qinghai sediments since 32 ka

PubMed Central

An, Zhisheng; Colman, Steven M.; Zhou, Weijian; Li, Xiaoqiang; Brown, Eric T.; Jull, A. J. Timothy; Cai, Yanjun; Huang, Yongsong; Lu, Xuefeng; Chang, Hong; Song, Yougui; Sun, Youbin; Xu, Hai; Liu, Weiguo; Jin, Zhangdong; Liu, Xiaodong; Cheng, Peng; Liu, Yu; Ai, Li; Li, Xiangzhong; Liu, Xiuju; Yan, Libin; Shi, Zhengguo; Wang, Xulong; Wu, Feng; Qiang, Xiaoke; Dong, Jibao; Lu, Fengyan; Xu, Xinwen

2012-01-01

Two atmospheric circulation systems, the mid-latitude Westerlies and the Asian summer monsoon (ASM), play key roles in northern-hemisphere climatic changes. However, the variability of the Westerlies in Asia and their relationship to the ASM remain unclear. Here, we present the longest and highest-resolution drill core from Lake Qinghai on the northeastern Tibetan Plateau (TP), which uniquely records the variability of both the Westerlies and the ASM since 32 ka, reflecting the interplay of these two systems. These records document the anti-phase relationship of the Westerlies and the ASM for both glacial-interglacial and glacial millennial timescales. During the last glaciation, the influence of the Westerlies dominated; prominent dust-rich intervals, correlated with Heinrich events, reflect intensified Westerlies linked to northern high-latitude climate. During the Holocene, the dominant ASM circulation, punctuated by weak events, indicates linkages of the ASM to orbital forcing, North Atlantic abrupt events, and perhaps solar activity changes. PMID:22943005

Taxonomic and functional diversity provides insight into microbial pathways and stress responses in the saline Qinghai Lake, China.

PubMed

Huang, Qiuyuan; Briggs, Brandon R; Dong, Hailiang; Jiang, Hongchen; Wu, Geng; Edwardson, Christian; De Vlaminck, Iwijn; Quake, Stephen

2014-01-01

Microbe-mediated biogeochemical cycles contribute to the global climate system and have sensitive responses and feedbacks to environmental stress caused by climate change. Yet, little is known about the effects of microbial biodiversity (i.e., taxonmic and functional diversity) on biogeochemical cycles in ecosytems that are highly sensitive to climate change. One such sensitive ecosystem is Qinghai Lake, a high-elevation (3196 m) saline (1.4%) lake located on the Tibetan Plateau, China. This study provides baseline information on the microbial taxonomic and functional diversity as well as the associated stress response genes. Illumina metagenomic and metatranscriptomic datasets were generated from lake water samples collected at two sites (B and E). Autotrophic Cyanobacteria dominated the DNA samples, while heterotrophic Proteobacteria dominated the RNA samples at both sites. Photoheterotrophic Loktanella was also present at both sites. Photosystem II was the most active pathway at site B; while, oxidative phosphorylation was most active at site E. Organisms that expressed photosystem II or oxidative phosphorylation also expressed genes involved in photoprotection and oxidative stress, respectively. Assimilatory pathways associated with the nitrogen cycle were dominant at both sites. Results also indicate a positive relationship between functional diversity and the number of stress response genes. This study provides insight into the stress resilience of microbial metabolic pathways supported by greater taxonomic diversity, which may affect the microbial community response to climate change.

Taxonomic and Functional Diversity Provides Insight into Microbial Pathways and Stress Responses in the Saline Qinghai Lake, China

PubMed Central

Dong, Hailiang; Jiang, Hongchen; Wu, Geng; Edwardson, Christian; De Vlaminck, Iwijn; Quake, Stephen

2014-01-01

Microbe-mediated biogeochemical cycles contribute to the global climate system and have sensitive responses and feedbacks to environmental stress caused by climate change. Yet, little is known about the effects of microbial biodiversity (i.e., taxonmic and functional diversity) on biogeochemical cycles in ecosytems that are highly sensitive to climate change. One such sensitive ecosystem is Qinghai Lake, a high-elevation (3196 m) saline (1.4%) lake located on the Tibetan Plateau, China. This study provides baseline information on the microbial taxonomic and functional diversity as well as the associated stress response genes. Illumina metagenomic and metatranscriptomic datasets were generated from lake water samples collected at two sites (B and E). Autotrophic Cyanobacteria dominated the DNA samples, while heterotrophic Proteobacteria dominated the RNA samples at both sites. Photoheterotrophic Loktanella was also present at both sites. Photosystem II was the most active pathway at site B; while, oxidative phosphorylation was most active at site E. Organisms that expressed photosystem II or oxidative phosphorylation also expressed genes involved in photoprotection and oxidative stress, respectively. Assimilatory pathways associated with the nitrogen cycle were dominant at both sites. Results also indicate a positive relationship between functional diversity and the number of stress response genes. This study provides insight into the stress resilience of microbial metabolic pathways supported by greater taxonomic diversity, which may affect the microbial community response to climate change. PMID:25365331

Influence of long-range atmospheric transportation (LRAT) on mono-to octa-chlorinated PCDD/Fs levels and distributions in soil around Qinghai Lake, China.

PubMed

Han, Ying; Liu, Wenbin; Hansen, Hans Chr Bruun; Chen, Xuebin; Liao, Xiao; Li, Haifeng; Wang, Mengjing; Yan, Nan

2016-08-01

Long-range atmospheric transportation (LRAT) of persistent organic pollutants followed by their deposition in cold, arid regions is of wide concern. This problem occurs at Qinghai Lake in the northeastern Tibetan Plateau, a sparsely populated area with extreme weather conditions and little current or historical anthropogenic pollution. The concentrations and distribution patterns of the mono-to octa-chlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) congeners in surface soil samples collected from around Qinghai Lake were quantified. Concentration differences between low-(mono-to tri-) chlorinated PCDD/Fs and high-(tetra-to octa-) chlorinated PCDD/Fs were measured. High PCDD/F levels were detected, with total concentrations of 15,108 ± 6323 pg/g for the 27 PCDD/F congeners and 15,104 ± 6324 pg/g for the low-chlorinated PCDD/Fs. The concentrations of 17 2,3,7,8-substituted PCDD/Fs were only 3.1 ± 4.4 pg/g and the corresponding international toxicity equivalency (I-TEQ) was 0.11 ± 0.22 pg I-TEQ/g. Given their higher vapor pressures and lower boiling points, low-chlorinated PCDD/Fs, were predominantly gaseous, whereas high-chlorinated PCDD/Fs were predominantly solid, indicating that there is a higher potential for long-range transport of low-chlorinated PCDD/Fs. Overall, because of their high LRAT potential, low-chlorinated PCDD/Fs may pose a greater risk to local ecosystems in cold, remote areas than high-chlorinated PCDD/Fs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Population models of burrowing mayfly recolonization in Western Lake Erie

USGS Publications Warehouse

Madenjian, C.P.; Schloesser, D.W.; Krieger, K.A.

1998-01-01

Burrowing mayflies, Hexagenia spp. (H. limbata and H. rigida), began recolonizing western Lake Erie during the 1990s. Survey data for mayfly nymph densities indicated that the population experienced exponential growth between 1991 and 1997. To predict the time to full recovery of the mayfly population, we fitted logistic models, ranging in carrying capacity from 600 to 2000 nymphs/m2, to these survey data. Based on the fitted logistic curves, we forecast that the mayfly population in western Lake Erie would achieve full recovery between years 1998 and 2000, depending on the carrying capacity of the western basin. Additionally, we estimated the mortality rate of nymphs in western Lake Erie during 1994 and then applied an age-based matrix model to the mayfly population. The results of the matrix population modeling corroborated the exponential growth model application in that both methods yielded an estimate of the population growth rate, r, in excess of 0.8 yr-1. This was the first evidence that mayfly populations are capable of recolonizing large aquatic ecosystems at rates comparable with those observed in much smaller lentic ecosystems. Our model predictions should prove valuable to managers of power plant facilities along the western basin in planning for mayfly emergences and to managers of the yellow perch (Perca flavescens) fishery in western Lake Erie.

The response of lake area and vegetation cover variations to climate change over the Qinghai-Tibetan Plateau during the past 30years.

PubMed

Zhang, Zengxin; Chang, Juan; Xu, Chong-Yu; Zhou, Yang; Wu, Yanhong; Chen, Xi; Jiang, Shanshan; Duan, Zheng

2018-09-01

Lakes and vegetation are important factors of the Earth's hydrological cycle and can be called an "indicator" of climate change. In this study, long-term changes of lakes' area and vegetation coverage in the Qinghai-Tibetan Plateau (QTP) and their relations to the climate change were analyzed by using Mann-Kendall method during the past 30years. Results showed that: 1) the lakes' area of the QTP increased significantly during the past 30years as a whole, and the increasing rates have been dramatically sped up since the year of 2000. Among them, the area of Ayakekumu Lake has the fastest growing rate of 51.35%, which increased from 618km 2 in the 1980s to 983km 2 in the 2010s; 2) overall, the Normalized Difference Vegetation Index (NDVI) increased in the QTP during the past 30years. Above 79% of the area in the QTP showed increasing trend of NDVI before the year of 2000; 3) the air temperature increased significantly, the precipitation increased slightly, and the pan evaporation decreased significantly during the past 30years. The lake area and vegetation coverage changes might be related to the climate change. The shifts in the temporal climate trend occurred around the year 2000 had led the lake area and vegetation coverage increasing. This study is of importance in further understanding the environmental changes under global warming over the QTP. Copyright © 2018 Elsevier B.V. All rights reserved.

Changes in the bottom fauna of western Lake Erie

USGS Publications Warehouse

Manny, Bruce A.; Schloesser, D.W.; Munawar, M.; Edsall, T.; Munawar, I.F.

1999-01-01

The bottom fauna of western Lake Erie has changed dramatically over the past 50 years in response to environmental degradation and biological invasions. In 1953, low dissolved oxygen reduced the biodiversity of that fauna, especially burrowing mayflies and freshwater mussels (Unionidae). Canada and the United States signed the Great Lakes Water Quality Agreement in 1972. By 1982, over 7 billion dollars were spent to improve wastewater treatment plants in the Great Lakes Basin. To assess how the bottom fauna responded to pollution abatement measures, we studied the distribution, abundance, and diversity of bottom fauna in western Lake Erie in 1982 and compared our findings to those of Carr and Hiltunen (1965). Zebra mussels (Dreissena polymorpha) invaded Lake Erie in 1986 and greatly altered these waters. For perspective, we also compared our results to bottom fauna present at the same stations in 1930 (by reference to data in Carr and Hiltunen, 1965) and reviewed the responses of burrowing mayflies and freshwater mussels to the zebra mussel invasion.

Changing abundance of Hexagenia mayfly nymphs in western Lake Erie of the Laurentian Great Lakes: Impediments to assessment of lake recovery?

USGS Publications Warehouse

Schloesser, D.W.; Nalepa, T.F.

2001-01-01

After an absence of 40 years, mayfly nymphs of the genus Hexagenia were found in sediments of western Lake Erie of the Laurentian Great Lakes in 1993 and, by 1997, were abundant enough to meet a mayfly-density management goal (ca. 350 nymphs m—2) based on pollution-abatement programs. We sampled nymphs in western Lake Erie and Lake St. Clair, located upstream of western Lake Erie, to determine the importance of seasonal abundance and life-history characteristics of nymphs (e.g., emergence and recruitment) on density estimates relative to the mayfly-density management goal. Two types of density patterns were observed: (1) densities were relatively high in spring and gradually decreased through late summer (observed in Lake Erie and Lake St. Clair in 1997 and Lake St. Clair in 1999) and (2) densities were relatively high in spring, gradually decreased to mid summer, abruptly decreased in mid summer, and then increased between summer and late fall (Lake Erie and Lake St. Clair in 1998 and Lake Erie in 1999). Length-frequency distributions of nymphs and observations of adults indicate that the primary cause for the two density patterns was attributed to failed (first pattern) and successful (second pattern) reproduction and emergence of nymphs into adults in mid summer. Gradual declines in densities were attributed to mortality of nymphs. Our results indicate that caution should be used when evaluating progress of pollution-abatement programs based on mayfly densities because recruitment success is variable both between and within years. Additionally, the interpretation of progress toward management goals, relative to the restoration of Hexagenia populations in the Great Lakes and possibly other water bodies throughout the world, is influenced by the number of years in which consequtive collections are made.

Drivers of pluvial lake distributions in western North America

NASA Astrophysics Data System (ADS)

Ibarra, D. E.; Oster, J. L.; Winnick, M.; Caves, J. K.; Ritch, A. J.; Chamberlain, C. P.; Maher, K.

2016-12-01

The distribution of large inland lakes in western North America during the Plio-Pleistocene is intimately linked to the regional hydroclimate and moisture delivery dynamics. We investigate the climatological conditions driving terminal basin lakes in western North America during the mid-Pliocene warm period and the latest Pleistocene glacial maximum. Lacustrine deposits and geologic proxies suggest that lakes and wet conditions persisted during both warm and cold periods in the southwest, despite dramatically different global climate, ice sheet configuration and pCO2 levels. We use two complementary methods to quantify the hydroclimate drivers of terminal basin lake levels. First, a quantitative proxy-model comparison is conducted using compilations of geologic proxies and an ensemble of climate models. We utilize archived climate model simulations of the Last Glacial Maximum (21 ka, LGM) and mid-Pliocene (3.3 Ma) produced by the Paleoclimate Modelling Intercomparison Project (PMIP and PlioMIP). Our proxy network is made up of stable isotope records from caves, soils and paleosols, lake deposits and shorelines, glacier chronologies, and packrat middens. Second, we forward model the spatial distribution of lakes in the region using a Budyko framework to constrain the water balance for terminally draining watersheds, and make quantitative comparisons to mapped lacustrine shorelines and outcrops. Cumulatively these two approaches suggest that reduced evaporation and moderate increases in precipitation, relative to modern, drove moderate to large pluvial lakes during the LGM in the Great Basin. In contrast, larger precipitation increases appear to be the primary driver of lake levels during the mid-Pliocene in the southwest, with this spatial difference suggesting a role for El Niño teleconnections. These results demonstrate that during past periods of global change patterns of `dry-gets-drier, wet-gets-wetter' do not hold true for western North America.

Recovery of burrowing mayflies (Ephemeroptera: Ephemeridae: Hexagenia) in western Lake Erie

USGS Publications Warehouse

Krieger, Kenneth A.; Schloesser, Don W.; Manny, Bruce A.; Trisler, Carmen E.; Heady, Susan E.; Ciborowski, Jan J.H.; Muth, Kenneth M.

1996-01-01

Burrowing mayflies (Hexagenia spp.) are native to western Lake Erie and were abundant until the 1950s, when they disappeared due to degraded water and sediment quality. Nymphs were absent from the sediments of most of western Lake Erie after the 1950s, although small, widely disjunct populations apparently persisted near shore. Sediment samples collected in 1993 revealed several small populations near the western and southern shores and beyond the mouths of the Detroit and Maumee rivers. A larger population was found in the southern island area, but nymphs were absent in the middle of the basin. By 1995, nymphs had spread throughout the western half and eastern end of the basin but remained absent from the middle of the basin. These data indicate thatHexagenia began recolonizing nearshore areas before offshore areas. Increasingly large swarms of winged Hexagenia on shore and over the lake between 1992 and 1994 further indicate that mayflies are recolonizing the basin. Factors that have permitted Hexageniarecovery in western Lake Erie probably include improved sediment and water quality attributed to pollution abatement programs implemented after the early 1970s, and perhaps environmental changes in the early 1990s attributed to effects of the exotic zebra mussel (Dreissena polymorpha).

Visual observations of historical lake trout spawning grounds in western Lake Huron

USGS Publications Warehouse

Nester, Robert T.; Poe, Thomas P.

1987-01-01

Direct underwater video observations were made of the bottom substrates at 12 spawning grounds formerly used by lake trout Salvelinus namaycush in western Lake Huron to evaluate their present suitability for successful reproduction by lake trout. Nine locations examined north of Saginaw Bay in the northwestern end of the lake are thought to provide the best spawning habitat. The substrate at these sites consisted of angular rough cobble and rubble with relatively deep interstitial spaces (a?Y 0.5 m), small amounts of fine sediments, and little or no periphytic growth. Conditions at the three other sampling locations south of Saginaw Bay seemed much less suitable for successful reproduction based on the reduced area of high-quality substrate, shallow interstitial spaces, high infiltration of fine sediments, and greater periphytic growth.

Vertical Mixing In Western Lake Constance Due To Long Internal Waves

NASA Astrophysics Data System (ADS)

Boehrer, B.

Current profiles in the pelagic waters of western Lake Constance have been broken up into modes of the internal wave equation [1,2]. All current profiles can be well represented by a combination of the first and second mode wave. The temporal vari- ation of the modal composition with the interaction of the first and second mode im- plies current shear at varying depths. From current and density profiles, the gradient Richardson number can be evaluated in its spatial and temporal pattern with occa- tional occurence of supercritical values at all depths, also in the deep hypolimnion. An empiric connection between gradient Richardson number and diapycnical mixing [3] is applied to yield a profile of vertical transport coefficients, which can be com- pared with transport coefficients from gradient flux calculations of temperature and electrical conductivity profiles [4]. [1] B. Boehrer, J. Ilmberger and K.O. Münnich (2000): Vertical Structure of Current in Western Lake Constance, JGR-Oceans, 105 (12), 28823-28835 [2] B. Boehrer (2000): Modal Response of a Deep Stratified Lake: Western Lake Con- stance, JGR-Oceans, 105 (12), 28837-28845 [3] H. Peeters, M.C. Gregg and J.M. Toole (1988): On the parameterization of equa- torial turbulence, JGR, 93, 1199-1218 [4] G. Heinz, J. Ilmberger and M. Schimmele (1990): Vertical Mixing in Überlinger See, western part of Lake Constance, Aquat. Sci., 52(3), 256-268

FORAGE FISH AND ZOOPLANKTON COMMUNITY COMPOSITION IN WESTERN LAKE SUPERIOR

EPA Science Inventory

We assessed the abundance, size, and species composition of the fish and zooplankton communities of western Lake Superior during 1996 and 1997. Data were analyzed for 3 ecoregions (Duluth-Superior (1), Apostle Islands (2), Minnesota coast (3) differing in lake bathymetry, phsiodo...

Lake Carnegie, Western Australia

NASA Technical Reports Server (NTRS)

2002-01-01

Ephemeral Lake Carnegie, in Western Australia, fills with water only during periods of significant rainfall. In dry years, it is reduced to a muddy marsh. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on May 19, 1999. This is a false-color composite image made using shortwave infrared, infrared, and red wavelengths. The image has also been sharpened using the sensor's panchromatic band. Image provided by the USGS EROS Data Center Satellite Systems Branch. This image is part of the ongoing Landsat Earth as Art series.

Identification, movement, growth, mortality, and exploitation of walleye stocks in Lake St. Clair and the western basin of Lake Erie

USGS Publications Warehouse

Haas, Robert C.; Fabrizio, Mary C.; Todd, Thomas N.

1988-01-01

The harvest of walleye by sport and commercial fisheries in lakes St. Clair and Erie is under a cooperative management program involving several states and two countries. In this report we present the results of a long-term tag-recapture study as well as corroborative evidence of stock discreteness fromstudies of population characteristics such as growth and allelic frequencies of walleye in these waters. Walleye were tagged in the spring from 1975-87 in lakes St. Clair and Erie. Tag-recapture data indicate a general tendency for walleye to move northward after tagging. Walleye tagged in Lake St. Clair had higher recovery rates and lower survival rates than walleye tagged in Lake Erie. A reward-tag study in Lake St. Clair provided an estimate of a non-reporting rate of approximately 33% which is comparable to rates in the literature for other species. Data from the Ontario commercial (gill-net) fishery, Michigan Department of Natural Resources trap-net surveys, and sport fisheries from western Lake Erie and Lake St. Clair were analyzed with a catch-at-age model which permitted estimation of population abundance (12.2 to 34.5 million fish), fishing mortality rate (0.19 to 0.37), and annual survival rate (0.57 to 0.68). It appears that exploitation rates for the sport fishery in the western basin exceeded those of the commercial fishery from 1978-82. In recent years (1983-87), exploitation rates were comparable. Average abundance and catch of walleye in the western basin were 12.2 million and 3.4 million fish in 1978-82; average abundance and catch in 1983-87 were 34.5 and 5.2 million fish. We found good agreement between the estimate of the harvest from creel surveys and that from the catch-at-age model for Lake Erie. Walleye abundance and harvest in Lake St. Clair were 10% of the values for the western basin of Lake Erie. Two discrete stocks were delineated be analysis of allelic frequencies of samples from Lake St. Clair and Lake Erie spawning populations. These

Links related to the Western Lake Erie Basin

EPA Pesticide Factsheets

Western Lake Erie Basin, near Toledo (Ohio) of the Urban Waters Federal Partnership (UWFP) reconnects urban communities with their waterways by improving coordination among federal agencies and collaborating with community-led efforts

Gymnocypris przewalskii decreases cytosolic carbonic anhydrase expression to compensate for respiratory alkalosis and osmoregulation in the saline-alkaline lake Qinghai.

PubMed

Yao, Zongli; Guo, Wenfei; Lai, Qifang; Shi, Jianquan; Zhou, Kai; Qi, Hongfang; Lin, Tingting; Li, Ziniu; Wang, Hui

2016-01-01

Naked carp (Gymnocypris przewalskii), endemic to the saline-alkaline Lake Qinghai, have the capacity to tolerate combined high salinity and alkalinity, but migrate to spawn in freshwater rivers each year. In this study, the full-length cDNA of the cytosolic carbonic anhydrase c isoform of G. przewalskii (GpCAc) was amplified and sequenced; mRNA levels and enzyme activity of GpCAc and blood chemistry were evaluated to understand the compensatory responses as the naked carp returned to the saline-alkaline lake after spawning. We found that GpCAc had a total length of 1400 bp and encodes a peptide of 260 amino acids. Comparison of the deduced amino acid sequences and phylogenetic analysis showed that GpCAc was a member of the cytosolic carbonic anhydrase II-like c family. Cytosolic-carbonic-anhydrase-c-specific primers were used to analyze the tissue distribution of GpCAc mRNA expression. Expression of GpCAc mRNA was found in brain, gill, liver, kidney, gut, and muscle tissues, but primarily in the gill and posterior kidney; however, none was evident in red blood cells. Transferring fish from river water to lake water resulted in a respiratory alkalosis, osmolality, and ion rise in the blood, as well as significant decreases in the expression and enzyme activity of GpCAc in both the gill and kidney within 96 h. These results indicate that GpCAc may play an important role in the acclimation to both high salinity and carbonate alkalinity. Specifically, G. przewalskii decreases cytosolic carbonic anhydrase c expression to compensate for a respiratory alkalosis and to aid in osmoregulation during the transition from river to saline-alkaline lake.

Meetings and Events about Western Lake Erie Basin

EPA Pesticide Factsheets

Western Lake Erie Basin, near Toledo (Ohio), Louisiana of the Urban Waters Federal Partnership (UWFP) reconnects urban communities with their waterways by improving coordination among federal agencies and collaborating with community-led efforts

Environmental cost and pollution risk caused by the industrial transfer in Qinghai Province

NASA Astrophysics Data System (ADS)

Jiang, Qun'ou; Tang, Chengcai; Zhan, Jinyan; Zhang, Wei; Wu, Feng

2014-09-01

With the rising pressure due to energy consumption and costs of environmental protection and recovery, industrial transfer from the eastern to central and western areas has surged in China. However, extremely fragile ecological conditions and severe water shortage are significant hurdles for industry development in Western China. Whether the vulnerable environment can bear the pollution caused by the transferred industry from Eastern China becomes a significant issue. This study firstly estimates energy and environmental costs in different areas of China, and assesses the necessity to upgrade the industrial structure of Qinghai Province. Then the emissions of waste water, waste gas, and smoke caused by transferred industries are calculated by Input-Output Model. On the basis of the effect analysis of waste emission on environment, pollution risks of Qinghai province are assessed. The results illustrate that the costs of environmental protection and recovery in China have a gradient distribution, of which the energy efficiency is lower while environmental costs are higher in Western China. Industrial structure adjustment has different impacts on the pollution of different sectors. Although the development of machinery and equipment, hotels and catering services, and real estate, leasing, and business services has increased the emission of pollutants, it is offset by the decreasing emissions caused by other industries such as construction and metal products. Therefore, although economic development will increase environmental pollution, industrial adjustments can effectively decrease waste water and waste gas emissions to reduce the pollution risk. It should be noted that there are still tremendous challenges for industrial transfer in Qinghai Province to coordinate the environment and industry development.

Historical Records of Mercury Stable Isotopes in Sediments of Tibetan Lakes

NASA Astrophysics Data System (ADS)

Yin, Runsheng; Feng, Xinbin; Hurley, James P.; Krabbenhoft, David P.; Lepak, Ryan F.; Kang, Shichang; Yang, Handong; Li, Xiangdong

2016-03-01

The Tibetan Plateau (TP), known as the “Third Pole”, is a critical zone for atmospheric mercury (Hg) deposition. Increasing anthropogenic activities in the globe leads to environmental changes, which may affect the loading, transport and deposition of Hg in the environment. However, the deposition history and geochemical cycling of Hg in the TP is still uncertain. Our records of Hg and Hg isotopes in sediment profiles of the two largest lakes in the TP, Lake Qinghai and Nam Co, show increased Hg influx since last century, with the maximum Hg influx enrichment ratios of 5.4 and 3.5 in Lake Qinghai and Nam Co, respectively. Shifts in negative δ 202Hg in Lake Qinghai (-4.55 to -3.15‰) and Nam Co (-5.04 to -2.16‰) indicate increased atmospheric Hg deposition through rainfall, vegetation and runoff of soils. Mass independent fractionation of both even-Hg (∆ 200Hg: +0.05 to +0.10‰) and odd-Hg (∆ 199Hg: +0.12 to +0.31‰) isotopes were observed. Positive Δ 200Hg suggest high proportion of precipitation-derived Hg in the TP, whereas the positive Δ 199Hg results from Hg(II) photo-reduction. Both lakes show increasing Δ 199Hg since the 1900 s, and we conclude that with the decrease of ice duration, Hg(II) photo-reduction may have been accelerated in these TP lakes.

Historical Records of Mercury Stable Isotopes in Sediments of Tibetan Lakes.

PubMed

Yin, Runsheng; Feng, Xinbin; Hurley, James P; Krabbenhoft, David P; Lepak, Ryan F; Kang, Shichang; Yang, Handong; Li, Xiangdong

2016-03-21

The Tibetan Plateau (TP), known as the "Third Pole", is a critical zone for atmospheric mercury (Hg) deposition. Increasing anthropogenic activities in the globe leads to environmental changes, which may affect the loading, transport and deposition of Hg in the environment. However, the deposition history and geochemical cycling of Hg in the TP is still uncertain. Our records of Hg and Hg isotopes in sediment profiles of the two largest lakes in the TP, Lake Qinghai and Nam Co, show increased Hg influx since last century, with the maximum Hg influx enrichment ratios of 5.4 and 3.5 in Lake Qinghai and Nam Co, respectively. Shifts in negative δ (202)Hg in Lake Qinghai (-4.55 to -3.15‰) and Nam Co (-5.04 to -2.16‰) indicate increased atmospheric Hg deposition through rainfall, vegetation and runoff of soils. Mass independent fractionation of both even-Hg (∆ (200)Hg: +0.05 to +0.10‰) and odd-Hg (∆ (199)Hg: +0.12 to +0.31‰) isotopes were observed. Positive Δ (200)Hg suggest high proportion of precipitation-derived Hg in the TP, whereas the positive Δ (199)Hg results from Hg(II) photo-reduction. Both lakes show increasing Δ (199)Hg since the 1900 s, and we conclude that with the decrease of ice duration, Hg(II) photo-reduction may have been accelerated in these TP lakes.

The role of clay minerals in the preservation of organic matter in sediments of Qinghai Lake, NW China

USGS Publications Warehouse

Yu, Bingsong; Dong, Hailiang; Jiang, Hongchen; Lv, Guo; Eberl, Dennis D.; Li, Shanying; Kim, Jinwook

2009-01-01

The role of saline lake sediments in preserving organic matter has long been recognized. In order to further understand the preservation mechanisms, the role of clay minerals was studied. Three sediment cores, 25, 57, and 500 cm long, were collected from Qinghai Lake, NW China, and dissected into multiple subsamples. Multiple techniques were employed, including density fractionation, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), total organic carbon (TOC) and carbon compound analyses, and surface area determination. The sediments were oxic near the water-sediment interface, but became anoxic at depth. The clay mineral content was as much as 36.8%, consisting mostly of illite, chlorite, and halloysite. The TEM observations revealed that organic matter occurred primarily as organic matter-clay mineral aggregates. The TOC and clay mineral abundances are greatest in the mid-density fraction, with a positive correlation between the TOC and mineral surface area. The TOC of the bulk sediments ranges from 1 to 3% with the non-hydrocarbon fraction being predominant, followed by bitumen, saturated hydrocarbon, aromatic hydrocarbons, and chloroform-soluble bitumen. The bimodal distribution of carbon compounds of the saturated hydrocarbon fraction suggests that organic matter in the sediments was derived from two sources: terrestrial plants and microorganisms/algae. Depthrelated systematic changes in the distribution patterns of the carbon compounds suggest that the oxidizing conditions and microbial abundance near the water-sediment interface promote degradation of labile organic matter, probably in adsorbed form. The reducing conditions and small microbial biomass deeper in the sediments favor preservation of organic matter, because of the less labile nature of organic matter, probably occurring within clay mineral-organic matter aggregates that are inaccessible to microorganisms. These results have important implications for our

The Effect of Lake Temperatures and Emissions on Ozone Exposure in the Western Great Lakes Region

Treesearch

Jerome D. Fast; Warren E. Heilman

2003-01-01

A meteorological-chemical model with a 12-km horizontal grid spacing was used to simulate the evolution of ozone over the western Great Lakes region during a 30-day period in the summer of 1999. Lake temperatures in the model were based on analyses derived from daily satellite measurements. The model performance was evaluated using operational surface and upper-air...

One-century sedimentary record of heavy metal pollution in western Taihu Lake, China.

PubMed

Li, Yan; Zhou, Shenglu; Zhu, Qing; Li, Baojie; Wang, Junxiao; Wang, Chunhui; Chen, Lian; Wu, Shaohua

2018-05-16

Long-term trends of sediment compositions are important for assessing the impact of human activities on the sediment and protecting the sediment environment. In this study, based on the contents of heavy metals and the Pb isotope ratios in lake sediments, atmospheric dustfall and soil in Yixing, China, the representative heavy metals (Zn, Pb, Cr and Cd) in lake sediments from western Taihu Lake were studied. The evolution history of heavy metals in the local environment was constructed for the past 100 years. From 1892 to the 1990s, the anthropogenic fluxes of the representative heavy metals were negligible, indicating minimal anthropogenic emissions of heavy metals. Since the 1990s, anthropogenic fluxes of the representative heavy metals began to increase, concurrent with the economic growth and development in the western Taihu Lake Basin after the Chinese economic reform. The maximum flux percentage of the heavy metals in the sediments, caused by human activities, is 23.0% for Zn, 31.6% for Pb, 39.5% for Cr and 85.3% for Cd, indicating that most of the Cd comes from human activities. The Cd content in the western Taihu Lake Basin was significantly higher than that in the other areas, and the rapid development of the industry in the western Taihu Lake Basin and ceramics in Yixing led to the enrichment of heavy metals in local sediments. Since the 21st century, measures have been taken to control the pollution of heavy metals, including the increase in local government attention and the deployment of environmental monitoring technology. However, heavy metal content remains high, and the Pb content is still increasing. The ratios of Pb isotopes show that the main sources of heavy metals in the western Taihu Lake sediments, the local soil of Yixing and the atmospheric dustfall are coal combustion, leaded gasoline combustion, industrial wastewater and domestic sewage. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dramatic and long-term lake level changes in the Qinghai-Tibet Plateau from Cryosat-2 altimeter: validation and augmentation by results from repeat altimeter missions and satellite imagery

NASA Astrophysics Data System (ADS)

Hwang, Cheinway; Huang, YongRuei; Cheng, Ys; Shen, WenBin; Pan, Yuanjin

2017-04-01

The mean elevation of the Qinghai-Tibet Plateau (QTP) exceeds 4000 m. Lake levels in the QTP are less affected by human activities than elsewhere, and may better reflect the state of contemporary climate change. Here ground-based lake level measurements are rare. Repeat altimeter missions, particularly those from the TOPEX and ERS series of altimetry, have provided long-term lake level observations in the QTP, but their large cross-track distances allow only few lakes to be monitored. In contrast, the Cryosat-2 altimeter, equipped with the new sensor SIRAL (interferometric/ synthetic aperture radar altimeter), provides a much better ranging accuracy and a finer spatial coverage than these repeated missions, and can detect water level changes over a large number of lakes in the QTP. In this study, Cryosat-2 data are used to determine lake level changes over 75˚E-100˚E and 28˚N-37.5˚N, where Cryosat-2 covers 60 lakes and SARAL/ AltiKa covers 32 lakes from 2013 to 2016. Over a lake, Cryosat-2 in different cycles can pass through different spots of the lake, making the numbers of observations non-uniform and requiring corrections for lake slopes. Four cases are investigated to cope with these situations: (1) neglecting inconsistency in data volume and lake slopes (2) considering data volume, (3) considering lake slopes only, and (4) considering both data volume and lake slopes. The CRYOSAT-2 result is then compared with the result from the SARAL to determine the best case. Because Cryosat-2 is available from 2010 to 2016, Jason-2 data are used to fill gaps between the time series of Cryosat-2 and ICESat (2003-2009) to obtain >10 years of lake level series. The Cryosat-2 result shows dramatic lake level rises in Lakes Kusai, Zhuoaihu and Salt in 2011 caused by floods. Landsat satellite imagery assists the determination and interpretation of such rises.

Water quality of Fremont Lake and New Fork Lakes, western Wyoming; a progress report

USGS Publications Warehouse

Peterson, D.A.; Averett, R.C.; Mora, K.L.

1987-01-01

Fremont Lake and New Fork Lakes in the New Fork River drainage of western Wyoming were selected for a comprehensive study of hydrologic processes affecting mountain lakes in the Rocky Mountains. Information is needed about lakes in this area to assess their response to existing and planned development. The concerns include regional issues such as acid precipitation from gas-sweetening plants, coal-fired powerplants, and smelters, as well as local issues, such as shoreline development and raising outlet control structures. Onsite measurements indicated strong thermal stratification in the lakes during the summer. Isothermal conditions occurred during December 1983 and May 1984. Mean phytoplankton concentrations were less than 5,000 cells/ml, and chlorophyll a concentrations were weakly correlated with phytoplankton concentrations. Zooplankton concentrations were small, less than 6 organisms/L. The numbers of benthic invertebrates/unit area in Fremont Lake were extremely small. The lake waters and inflow and outflow streams were chemically dilute solutions. Mean dissolved-solids concentrations were 13 mg/L in Fremont Lake and 24 mg/L in New Fork Lakes. Calcium and bicarbonate were the predominant ions. Concentrations of phosphorus and nitrogen usually were less than detection limits. Trace-metals concentrations in the lakes were similar to those in precipitation and generally were small. Dissolved organic-carbon concentrations were about 1 mg/L. Concentrations of fulvic and humic acids were relatively large in the inlet of Fremont Lake during the spring. Pine Creek has deposited 800 metric tons of sediment, on an annual average, to the delta of Fremont Lake. Most sediment is deposited during spring runoff. (USGS)

A database of georeferenced nutrient chemistry data for mountain lakes of the Western United States

PubMed Central

Williams, Jason; Labou, Stephanie G.

2017-01-01

Human activities have increased atmospheric nitrogen and phosphorus deposition rates relative to pre-industrial background. In the Western U.S., anthropogenic nutrient deposition has increased nutrient concentrations and stimulated algal growth in at least some remote mountain lakes. The Georeferenced Lake Nutrient Chemistry (GLNC) Database was constructed to create a spatially-extensive lake chemistry database needed to assess atmospheric nutrient deposition effects on Western U.S. mountain lakes. The database includes nitrogen and phosphorus water chemistry data spanning 1964–2015, with 148,336 chemistry results from 51,048 samples collected across 3,602 lakes in the Western U.S. Data were obtained from public databases, government agencies, scientific literature, and researchers, and were formatted into a consistent table structure. All data are georeferenced to a modified version of the National Hydrography Dataset Plus version 2. The database is transparent and reproducible; R code and input files used to format data are provided in an appendix. The database will likely be useful to those assessing spatial patterns of lake nutrient chemistry associated with atmospheric deposition or other environmental stressors. PMID:28509907

Internal loading of phosphorus in western Lake Erie

USGS Publications Warehouse

Matisoff, Gerald; Kaltenberg, Eliza M.; Steely, Rebecca L.; Hummel, Stephanie K.; Seo, Jinyu; Gibbons, Kenneth J.; Bridgeman, Thomas B.; Seo, Youngwoo; Behbahani, Mohsen; James, William F.; Johnson, Laura; Doan, Phuong; Dittrich, Maria; Evans, Mary Anne; Chaffin, Justin D.

2016-01-01

This study applied eight techniques to obtain estimates of the diffusive flux of phosphorus (P) from bottom sediments throughout the western basin of Lake Erie. The flux was quantified from both aerobic and anaerobic incubations of whole cores; by monitoring the water encapsulated in bottom chambers; from pore water concentration profiles measured with a phosphate microelectrode, a diffusive equilibrium in thin films (DET) hydrogel, and expressed pore waters; and from mass balance and biogeochemical diagenetic models. Fluxes under aerobic conditions at summertime temperatures averaged 1.35 mg P/m2/day and displayed spatial variability on scales as small as a centimeter. Using two different temperature correction factors, the flux was adjusted to mean annual temperature yielding average annual fluxes of 0.43–0.91 mg P/m2/day and a western basin-wide total of 378–808 Mg P/year as the diffusive flux from sediments. This is 3–7% of the 11,000 Mg P/year International Joint Commission (IJC) target load for phosphorus delivery to Lake Erie from external sources. Using these average aerobic fluxes, the sediment contributes 3.0–6.3 μg P/L as a background internal contribution that represents 20–42% of the IJC Target Concentration of 15 μg P/L for the western basin. The implication is that this internal diffusive recycling of P is unlikely to trigger cyanobacterial blooms by itself but is sufficiently large to cause blooms when combined with external loads. This background flux may be also responsible for delayed response of the lake to any decrease in the external loading.

Recruitment of Hexagenia mayfly nymphs in western Lake Erie linked to environmental variability

USGS Publications Warehouse

Bridgeman, Thomas B.; Schloesser, Don W.; Krause, Ann E.

2006-01-01

After a 40-year absence caused by pollution and eutrophication, burrowing mayflies (Hexagenia spp.) recolonized western Lake Erie in the mid 1990s as water quality improved. Mayflies are an important food resource for the economically valuable yellow perch fishery and are considered to be major indicator species of the ecological condition of the lake. Since their reappearance, however, mayfly populations have suffered occasional unexplained recruitment failures. In 2002, a failure of fall recruitment followed an unusually warm summer in which western Lake Erie became temporarily stratified, resulting in low dissolved oxygen levels near the lake floor. In the present study, we examined a possible link between Hexagenia recruitment and periods of intermittent stratification for the years 1997-2002. A simple model was developed using surface temperature, wind speed, and water column data from 2003 to predict stratification. The model was then used to detect episodes of stratification in past years for which water column data are unavailable. Low or undetectable mayfly recruitment occurred in 1997 and 2002, years in which there was frequent or extended stratification between June and September. Highest mayfly reproduction in 2000 corresponded to the fewest stratified periods. These results suggest that even relatively brief periods of stratification can result in loss of larval mayfly recruitment, probably through the effects of hypoxia. A trend toward increasing frequency of hot summers in the Great Lakes region could result in recurrent loss of mayfly larvae in western Lake Erie and other shallow areas in the Great Lakes.

Soil water dynamics and evapotranspiration in alpine ecosystems in the NE of Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Li, Xiao-Yan; Zhang, Si-Yi; Ma, Yu-Jun

2015-04-01

Interactions between surface energy flux, evapotranspiration and soil water were poorly understood in the alpine ecosystems in the Qinghai-Tibet Plateau, which is a sensitive and vulnerable region to global climate change. For the first time, we continuously measured surface energy flux and soil water content (SWC) and estimated ET using bowen ratio energy balance method in the Qinghai Lake watershed, located in the northeast of Qinghai-Tibet Plateau between 2012 and 2013. The three ecosystems were Kobresia meadow (KMd.), Potentilla fruticosa shrub (PFSh.) and Achnatherum splendens steppe (ASSt.). Results indicated that there was a good negative correlation between ecosystem Bowen ratios and SWC in the growing season for the three ecosystems. Annual ET at KMd. and PFSh. was 16% and 3% less than local annual precipitation, while that at ASSt. was 26% larger than annual precipitation. Average annual ET was 507.9, 493.2 and 413.7 mm at PFSh., KMd. and ASSt., respectively. Fluctuations of daily ET at alpine ecosystems were primarily controlled by solar radiation, especially in the growing season, whereas, at ASSt. where precipitation and SWC was limited, ET was also controlled by water supply.

Radiocarbon dating of individual lignin phenols: a new approach for establishing chronology of late quaternary lake sediments.

PubMed

Hou, Juzhi; Huang, Yongsong; Brodsky, Corynn; Alexandre, Marcelo R; McNichol, Ann P; King, John W; Hu, Feng Sheng; Shen, Ji

2010-09-01

The reliability of chronology is a prerequisite for meaningful paleoclimate reconstructions from sedimentary archives. The conventional approach of radiocarbon dating bulk organic carbon in lake sediments is often hampered by the old carbon effect, i.e., the assimilation of ancient dissolved inorganic carbon (DIC) derived from carbonate bedrocks or other sources. Therefore, radiocarbon dating is ideally performed on organic compounds derived from land plants that use atmospheric CO(2) and rapidly delivered to sediments. We demonstrate that lignin phenols isolated from lake sediments using reversed phase high performance liquid chromatography (HPLC) can serve as effective (14)C dating materials for establishing chronology during the late Quaternary. We developed a procedure to purify lignin phenols, building upon a published method. By isolating lignin from standard wood reference substances, we show that our method yields pure lignin phenols and consistent ages as the consensus ages and that our procedure does not introduce radiocarbon contamination. We further demonstrate that lignin phenol ages are compatible with varve counted and macrofossil dated sediment horizons in Steel Lake and Fayetteville Green Lake. Applying the new method to lake sediment cores from Lake Qinghai demonstrates that lignin phenol ages in Lake Qinghai are consistently younger than bulk total organic carbon (TOC) ages which are contaminated by old carbon effect. We also show that the age offset between lignin and bulk organic carbon differs at different Lake Qinghai sedimentary horizons, suggesting a variable hard water effect at different times and that a uniform age correction throughout the core is inappropriate.

Spatiotemporal patterns of mercury accumulation in lake sediments of western North America

USGS Publications Warehouse

Drevnick, Paul; Cooke, Colin A.; Barraza, Daniella; Blais, Jules M.; Coale, Kenneth; Cumming, Brian F.; Curtis, Chris; Das, Biplob; Donahue, William F.; Eagles-Smith, Collin A.; Engstrom, Daniel R.; Fitzgerald, William F.; Furl, Chad V.; Gray, John R.; Hall, Roland I.; Jackson, Togwell A.; Laird, Kathleen R.; Lockhart, W. Lyle; Macdonald, Robie W.; Mast, M. Alisa; Mathieu, Callie; Muir, Derek C.G.; Outridge, Peter; Reinemann, Scott; Rothenberg, Sarah E.; Ruiz-Fernandex, Ana Carolina; St. Louis, V.L.; Sanders, Rhea; Sanei, Hamed; Skierszkan, Elliott; Van Metre, Peter C.; Veverica, Timothy; Wiklund, Johan A.; Wolfe, Brent B.

2016-01-01

For the Western North America Mercury Synthesis, we compiled mercury records from 165 dated sediment cores from 138 natural lakes across western North America. Lake sediments are accepted as faithful recorders of historical mercury accumulation rates, and regional and sub-regional temporal and spatial trends were analyzed with descriptive and inferential statistics. Mercury accumulation rates in sediments have increased, on average, four times (4×) from 1850 to 2000 and continue to increase by approximately 0.2 μg/m2 per year. Lakes with the greatest increases were influenced by the Flin Flon smelter, followed by lakes directly affected by mining and wastewater discharges. Of lakes not directly affected by point sources, there is a clear separation in mercury accumulation rates between lakes with no/little watershed development and lakes with extensive watershed development for agricultural and/or residential purposes. Lakes in the latter group exhibited a sharp increase in mercury accumulation rates with human settlement, stabilizing after 1950 at five times (5×) 1850 rates. Mercury accumulation rates in lakes with no/little watershed development were controlled primarily by relative watershed size prior to 1850, and since have exhibited modest increases (in absolute terms and compared to that described above) associated with (regional and global) industrialization. A sub-regional analysis highlighted that in the ecoregion Northwestern Forest Mountains, <1% of mercury deposited to watersheds is delivered to lakes. Research is warranted to understand whether mountainous watersheds act as permanent sinks for mercury or if export of “legacy” mercury (deposited in years past) will delay recovery when/if emissions reductions are achieved.

Active hematite concretion formation in modern acid saline lake sediments, Lake Brown, Western Australia

NASA Astrophysics Data System (ADS)

Bowen, Brenda Beitler; Benison, K. C.; Oboh-Ikuenobe, F. E.; Story, S.; Mormile, M. R.

2008-04-01

Concretions can provide valuable records of diagenesis and fluid-sediment interactions, however, reconstruction of ancient concretion-forming conditions can be difficult. Observation of modern hematite concretion growth in a natural sedimentary setting provides a rare glimpse of conditions at the time of formation. Spheroidal hematite-cemented concretions are actively precipitating in shallow subsurface sediments at Lake Brown in Western Australia. Lake Brown is a hypersaline (total dissolved solids up to 23%) and acidic (pH ˜ 4) ephemeral lake. The concretion host sediments were deposited between ˜ 1 and 3 ka, based on dating of stratigraphically higher and lower beds. These age constraints indicate that the diagenetic concretions formed < 3 ka, and field observations suggest that some are currently forming. These modern concretions from Lake Brown provide an example of very early diagenetic formation in acid and saline conditions that may be analogous to past conditions on Mars. Previously, the hematite concretions in the Burns formation on Mars have been interpreted as late stage diagenetic products, requiring long geologic time scales and multiple fluid flow events to form. In contrast, the Lake Brown concretions support the possibility of similar syndepositional to very early diagenetic concretion precipitation on Mars.

Trends in phosphorus loading to the western basin of Lake ...

EPA Pesticide Factsheets

Dave Dolan spent much of his career computing and compiling phosphorus loads to the Great Lakes. None of his work in this area has been more valuable than his continued load estimates to Lake Erie, which has allowed us to unambiguously interpret the cyanobacteria blooms and hypoxia development in the lake. To help understand the re-occurrence of cyanobacteria blooms in the Western Basin of Lake Erie, we have examined the phosphorus loading to the Western Basin over the past 15 years. Furthermore, we have examined the relative contributions from various tributaries and the Detroit River. On an annual basis the total phosphorus load has not exhibited a trend, other than being well correlated with flow from major tributaries. However, the dissolved reactive phosphorus (DRP) load has trended upward, returning to levels observed in the mid-1970s. This increase has largely been attributed to the increase in flow-weighted DRP concentration in the Maumee River. Over the period, about half of the phosphorus load comes from the Maumee River with the other half coming from the Detroit River; other tributaries contribute much small amounts to the load. Seasonal analysis shows the highest percentage of the load occurs in the spring during high flow events. We are very grateful to our friend Dave for making this type of analysis possible not applicable

Geochemistry and Mineralogy of Western Australian Salt Lake Sediments: Implications for Meridiani Planum on Mars.

PubMed

Ruecker, A; Schröder, C; Byrne, J; Weigold, P; Behrens, S; Kappler, A

2016-07-01

Hypersaline lakes are characteristic for Western Australia and display a rare combination of geochemical and mineralogical properties that make these lakes potential analogues for past conditions on Mars. In our study, we focused on the geochemistry and mineralogy of Lake Orr and Lake Whurr. While both lakes are poor in organic carbon (<1%), the sediments' pH values differ and range from 3.8 to 4.8 in Lake Orr and from 5.4 to 6.3 in Lake Whurr sediments. Lake Whurr sediments were dominated by orange and red sediment zones in which the main Fe minerals were identified as hematite, goethite, and tentatively jarosite and pyrite. Lake Orr was dominated by brownish and blackish sediments where the main Fe minerals were goethite and another paramagnetic Fe(III)-phase that could not be identified. Furthermore, a likely secondary Fe(II)-phase was observed in Lake Orr sediments. The mineralogy of these two salt lakes in the sampling area is strongly influenced by events such as flooding, evaporation, and desiccation, processes that explain at least to some extent the observed differences between Lake Orr and Lake Whurr. The iron mineralogy of Lake Whurr sediments and the high salinity make this lake a suitable analogue for Meridiani Planum on Mars, and in particular the tentative identification of pyrite in Lake Whurr sediments has implications for the interpretation of the Fe mineralogy of Meridiani Planum sediments. Western Australia-Salt lakes-Jarosite-Hematite-Pyrite-Mars analogue. Astrobiology 16, 525-538.

Salt lakes of Western Australia - Natural abiotic formation of volatile organic compounds

NASA Astrophysics Data System (ADS)

Krause, T.; Studenroth, S.; Mulder, I.; Tubbesing, C.; Kotte, K.; Ofner, J.; Junkermann, W.; Schöler, H. F.

2012-04-01

Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many ephemeral saline and hypersaline lakes with a wide range of hydrogeochemical parameters that have gradually changed over the last fifty years. Historically, the region was covered by eucalyptus trees and shrubs, but was cleared mainly within 10 years after WWII to make room for wheat and live stock. After the clearance of the deep rooted native plants the groundwater started to rise, bringing increased amounts of dissolved salts and minerals to the surface and discharging them into streams and lakes. Thus most of Western Australia is influenced by secondary salinisation (soil salting) [1]. Another problem is that the discharged minerals affect the pH of ground and surface water, which ranges from acidic to slightly basic. During the 2011 campaign surface water was measured with a pH between 2.5 and 7.1. Another phenomenon in Western Australia is the decrease of rainfall over the last decades assumed to be linked to the secondary salinisation. The rising saline and mineral rich groundwater increases the biotical and abiotical activity of the salt lakes. Halogenated and non-halogenated volatile organic compounds emitted from those lakes undergo fast oxidation and chemical reactions to form small particles modifying cloud microphysics and thus suppressing rain events [2]. Our objective is to gain a better understanding of this extreme environment with its hypersaline acidic lakes with regard to the potential abiotic formation of volatile organic compounds and its impact on the local climate. In spring 2011 fifty-three sediment samples from ten salt lakes in the Lake King region where taken, freeze-dried and ground. In order to simulate the abiotic formation of volatile organic compounds the soil samples were resuspended with water in gas-tight headspace vials. The headspace was measured using a purge and trap GC

Environmental and Groundwater Controls on Evaporation Rates of A Shallow Saline Lake in the Western Sandhills Nebraska, USA

NASA Astrophysics Data System (ADS)

Peake, C.; Riveros-Iregui, D.; Lenters, J. D.; Zlotnik, V. A.; Ong, J.

2013-12-01

The western Sand Hills of Nebraska exhibit many shallow saline lakes that actively mediate groundwater-lake-atmospheric exchanges. The region is home to the largest stabilized dune field in the western hemisphere. Most of the lakes in the western Sand Hills region are saline and support a wide range of ecosystems. However, they are also highly sensitive to variability in evaporative and groundwater fluxes, which makes them a good laboratory to examine the effects of climate on the water balance of interdunal lakes. Despite being semiarid, little is known about the importance of groundwater-surface water interactions on evaporative rates, or the effects of changes in meteorological and energy forcings on the diel, and seasonal dynamics of evaporative fluxes. Our study is the first to estimate evaporation rates from one of the hundreds of shallow saline lakes that occur in the western Sand Hills region. We applied the energy balance Bowen ratio method at Alkali Lake, a typical saline western Sand Hills lake, over a three-year period (2007-2009) to quantify summer evaporation rates. Daily evaporation rates averaged 5.5 mm/day from July through September and were largely controlled by solar radiation on a seasonal and diel scales. Furthermore, the range of annual variability of evaporation rates was low. Although less pronounced, groundwater level effects on evaporation rates were also observed, especially from August through October when solar radiation was lower. The lake exhibits significant fluctuation in lake levels and combined with a shallow lake bed, large changes in lake surface area are observed. Our findings also show that with the onset of summer conditions, lake surface area can change very rapidly (e.g. 24% of its surface area or ~16.6 hectares were lost in less than ~2 months). In every year summer evaporation exceeded annual rainfall by an average of 28.2% suggesting that groundwater is a significant component of the lake water balance, it is important

Expansion of tubenose gobies Proterorhinus semilunaris into western Lake Erie and potential effects on native species

USGS Publications Warehouse

Kocovsky, P.M.; Tallman, J.A.; Jude, D.J.; Murphy, D.M.; Brown, J.E.; Stepien, C.A.

2011-01-01

The Eurasian freshwater tubenose goby Proterorhinus semilunaris (formerly Proterorhinus marmoratus) invaded the Laurentian Great Lakes in the 1990s, presumably via ballast water from transoceanic cargo ships. Tubenose gobies spread throughout Lake St. Clair, its tributaries, and the Detroit River system, and also are present in the Duluth-Superior harbor of Lake Superior. Using seines and bottom trawls, we collected 113 tubenose gobies between July 2007 and August 2009 at several locations in western Lake Erie. The number and range of sizes of specimens collected suggest that that tubenose gobies have become established and self-sustaining in the western basin of Lake Erie. Tubenose gobies reached maximum densities in sheltered areas with abundant macrophyte growth, which also is their common habitat in native northern Black Sea populations. The diet of tubenose gobies was almost exclusively invertebrates, suggesting dietary overlap with other benthic fishes, such as darters (Etheostoma spp. and Percina sp.), madtoms (Noturus spp.), and sculpins (Cottus spp.). A single mitochondrial DNA haplotype was identified, which is the most common haplotype found in the original colonization area in the Lake St. Clair region, suggesting a founder effect. Tubenose gobies, like round gobies Neogobius melanostomus, have early life stages that drift owing to vertical migration, which probably allowed them to spread from areas of colonization. The Lake St. Clair-Lake Erie corridor appears to have served as an avenue for them to spread to the western basin of Lake Erie, and abundance of shallow macrophyte-rich habitats may be a key factor facilitating their further expansion within Lake Erie and the remainder of the Laurentian Great Lakes.

Climate change and its impacts on vegetation distribution and net primary productivity of the alpine ecosystem in the Qinghai-Tibetan Plateau.

PubMed

Gao, Qingzhu; Guo, Yaqi; Xu, Hongmei; Ganjurjav, Hasbagen; Li, Yue; Wan, Yunfan; Qin, Xiaobo; Ma, Xin; Liu, Shuo

2016-06-01

Changes in climate have caused impacts on ecosystems on all continents scale, and climate change is also projected to be a stressor on most ecosystems even at the rate of low- to medium-range warming scenarios. Alpine ecosystem in the Qinghai-Tibetan Plateau is vulnerable to climate change. To quantify the climate change impacts on alpine ecosystems, we simulated the vegetation distribution and net primary production in the Qinghai-Tibetan Plateau for three future periods (2020s, 2050s and 2080s) using climate projection for RCPs (Representative Concentration Pathways) RCP4.5 and RCP8.5 scenarios. The modified Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ model) was parameter and test to make it applicable to the Qinghai-Tibetan Plateau. Climate projections that were applied to LPJ model in the Qinghai-Tibetan Plateau showed trends toward warmer and wetter conditions. Results based on climate projections indicated changes from 1.3°C to 4.2°C in annual temperature and changes from 2% to 5% in annual precipitation. The main impacts on vegetation distribution was increase in the area of forests and shrubs, decrease in alpine meadows which mainly replaced by shrubs which dominated the eastern plateau, and expanding in alpine steppes to the northwest dominated the western and northern plateau. The NPP was projected to increase by 79% and 134% under the RCP4.5 and RCP8.5. The projected NPP generally increased about 200gC·m(-2)·yr(-1) in most parts of the plateau with a gradual increase from the eastern to the western region of the Qinghai-Tibetan Plateau at the end of this century. Copyright © 2016 Elsevier B.V. All rights reserved.

Lake deposits record evidence of large post-1505 AD earthquakes in western Nepal

NASA Astrophysics Data System (ADS)

Ghazoui, Z.; Bertrand, S.; Vanneste, K.; Yokoyama, Y.; Van Der Beek, P.; Nomade, J.; Gajurel, A.

2016-12-01

According to historical records, the last large earthquake that ruptured the Main Frontal Thrust (MFT) in western Nepal occurred in 1505 AD. Since then, no evidence of other large earthquakes has been found in historical records or geological archives. In view of the catastrophic consequences to millions of inhabitants of Nepal and northern India, intense efforts currently focus on improving our understanding of past earthquake activity and complement the historical data on Himalayan earthquakes. Here we report a new record, based on earthquake-triggered turbidites in lakes. We use lake sediment records from Lake Rara, western Nepal, to reconstruct the occurrence of seismic events. The sediment cores were studied using a multi-proxy approach combining radiocarbon and 210Pb chronologies, physical properties (X-ray computerized axial tomography scan, Geotek multi-sensor core logger), high-resolution grain size, inorganic geochemistry (major elements by ITRAX XRF core scanning) and bulk organic geochemistry (C, N concentrations and stable isotopes). We identified several sequences of dense and layered fine sand mainly composed of mica, which we interpret as earthquake-triggered turbidites. Our results suggest the presence of a synchronous event between the two lake sites correlated with the well-known 1505 AD earthquake. In addition, our sediment records reveal five earthquake-triggered turbidites younger than the 1505 AD event. By comparison with historical archives, we relate one of those to the 1833 AD MFT rupture. The others may reflect successive ruptures of the Western Nepal Fault System. Our study sheds light on events that have not been recorded in historical chronicles. Those five MMI>7 earthquakes permit addressing the problem of missing slip on the MFT in western Nepal and reevaluating the risk of a large earthquake affecting western Nepal and North India.

First-year growth, recruitment, and maturity of walleyes in western Lake Erie

USGS Publications Warehouse

Madenjian, Charles P.; Tyson, Jeffrey T.; Knight, Roger L.; Kershner, Mark W.; Hansen, Michael J.

1996-01-01

In some lakes, first-year growth of walleyes Stizostedion vitreum has been identified as an important factor governing recruitment of juveniles to the adult population. We developed a regression model for walleye recruitment in western Lake Erie by considering factors such as first-year growth, size of the spawning stock, the rate at which the lake warmed during the spring, and abundance of gizzard shad Dorosoma cepedianum. Gizzard shad abundance during the fall prior to spring walleye spawning explained over 40% of the variation in walleye recruitment. Gizzard shad are relatively high in lipids and are preferred prey for walleyes in Lake Erie. Therefore, the high degree of correlation between shad abundance and subsequent walleye recruitment supported the contention that mature females needed adequate lipid reserves during the winter to spawn the following spring. According to the regression analysis, spring warming rate and size of the parental stock also influenced walleye recruitment. Our regression model explained 92% of the variation in recruitment of age-2 fish into the Lake Erie walleye population from 1981 to 1993. The regression model is potentially valuable as a management tool because it could be used to forecast walleye recruitment to the fishery 2 years in advance. First-year growth was poorly correlated with recruitment, which may reflect the unusually low incidence of walleye cannibalism in western Lake Erie. In contrast, first-year growth was strongly linked to age at maturity.

Chemical characterization of dissolved organic matter in an alpine stream from thawing and collapsing permafrost to Qinghai Lake

NASA Astrophysics Data System (ADS)

Wang, Y.; Xu, Y.

2016-12-01

The Tibetan Plateau is the world's largest and highest plateau, approximately two thirds of which is covered by permafrost. Due to recent climate warming, large organic carbon stored in the permafrost is thawing and becomes available for transport to aquatic ecosystems (i.e., stream and lake) as dissolved organic matter (DOM) and fine particulate organic matter (POM). These DOM and POM are not only important food sources for the aquatic food web, but also a significant feedback if remineralized during transport. In this work, we collected water samples along a stream from the headwater in the Permafrost region to the downstream in the Qinghai Lake. The concentration and composition of DOM were determined using high temperature combustion analysis, UV- Vis absorption spectroscopy and fluorescence spectroscopy. The concentration of dissolved organic carbon decreased sharply from 13.87 mg/L to 4.32 mg/L from collapsing permafrost area (3850 m a.s.l.) to the foot of the mountain (3200 m a.s.l.), and then fluctuated in a narrow range between 3.00 mg/L and 4.50 mg/L. The DOM with high humic-like fluorescence, specific UV absorbance (SUVA254), and low spectral slope ratio (S275-295) and fluorescence index (FI) was observed in the headwater, which was distinct difference from that at the middle and downstream area where the DOM are less aromatic and low molecular weight. Meanwhile, the freshness index (β/α) increased slightly in mid and down-stream. This increasing trend for FI and β/α indicated a contribution of recently in situ produced DOM by aquatic bacteria and algae in the stream. We speculate that the biological process is an important way to cause the chemical change of DOM composition and concentration, and therefore the thawing and transport of permafrost carbon may play a key role in sustaining the alpine stream ecosystem.

Biogeochemistry of Lakes in Western Papua, Indonesia - First Results of a Pilot Study.

NASA Astrophysics Data System (ADS)

Kallmeyer, J.; Nomosatryo, S.; Henny, C.; Kopalit, H.

2016-12-01

Despite years of exploration for mineral and hydrocarbon resources, the lakes of Western Papua have received very little attention from a limnogeologic perspective. In some cases not even the maximum water depth of the lakes is published. The only research carried out so far focused on the fish and invertebrate fauna of the lakes, because the macrofauna of Papuan Lakes is significantly different from other islands of western Indonesia. Most lakes harbor numerous endemic species. We carried out a first limnogeologic pilot campaign in spring 2016 to measure water column profiles and take short (max 80 cm long) sediment cores.Lake Sentani is seated in Mesozoic mafic bedrock and consists of four separate basins with maximum water depths of 30 to 40 m. Three basins are connected by shallow sills and one by a natural canal. Although all four basins share almost identical surface water chemistry and exhibit sub- to anoxic bottom waters, each basin has its distinct water column stratification and sediment geochemistry. Despite its coastal location and minimal elevation we could not identify an influx of seawater into the lake. Lake Ayamaru is located further inland on a densely forested karstified carbonate platform. The lake level has dropped significantly in recent years due to water loss into the karst, further reduction of open water surface is caused by massive growth of Pistia. Currently the lake has a maximum depth of around 2 m. Its sediment is mainly composed of carbonate minerals and methane saturated. Due to the carbonate bedrock the lake is highly alkaline (up to 20 meq/L) despite its very low salinity. The initial analyses show that these lakes offer unique biogeochemical conditions that require further in-depth studies.Our research will expand to lakes Anggi Giji and Anggi Gida, which are at almost 2000 m elevation. They have maximum depths of around 200 m and much colder surface waters (12-20°C) compared to the other two lakes that have about 30�

Spatial patterns in assemblage structures of pelagic forage fish and zooplankton in western Lake Superior

USGS Publications Warehouse

Johnson, Timothy B.; Hoff, Michael H.; Trebitz, Anett S.; Bronte, Charles R.; Corry, Timothy D.; Kitchell, James F.; Lozano, Stephen J.; Mason, Doran M.; Scharold, Jill V.; Schram, Stephen T.; Schreiner, Donald R.

2004-01-01

We assessed abundance, size, and species composition of forage fish and zooplankton communities of western Lake Superior during August 1996 and July 1997. Data were analyzed for three ecoregions (Duluth-Superior, Apostle Islands, and the open lake) differing in bathymetry and limnological and biological patterns. Zooplankton abundance was three times higher in the Duluth-Superior and Apostle Islands regions than in the open lake due to the large numbers of rotifers. Copepods were far more abundant than Cladocera in all ecoregions. Mean zooplankton size was larger in the open lake due to dominance by large calanoid copepods although size of individual taxa was similar among ecoregions. Forage fish abundance and biomass was highest in the Apostle Islands region and lowest in the open lake ecoregion. Lake herring (Coregonus artedi), rainbow smelt (Osmerus mordax) and deepwater ciscoes (Coregonus spp.) comprised over 90% of the abundance and biomass of fishes caught in midwater trawls and recorded with hydroacoustics. Growth and condition of fish was good, suggesting they were not resource limited. Fish and zooplankton assemblages differed among the three ecoregions of western Lake Superior, due to a combination of physical and limnological factors related to bathymetry and landscape position.

Chemistry of selected high-elevation lakes in seven national parks in the western United States

USGS Publications Warehouse

Clow, David W.; Striegl, Robert G.; Nanus, Leora; Mast, M. Alisa; Campbell, Donald H.; Krabbenhoft, David P.

2002-01-01

A chemical survey of 69 high-altitude lakes in seven national parks in the western United States was conducted during the fallof 1999; the lakes were previously sampled during the fall of 1985, as part of the Western Lake Survey. Lakes in parks in the Sierra/southern Cascades (Lassen Volcanic, Yosemite, Sequoia/Kings Canyon National Parks) and in the southern RockyMountains (Rocky Mountain National Park) were very dilute; medianspecific conductance ranged from 4.4 to 12.2 μS cm-1 andmedian alkalinity concentrations ranged from 32.2 to 72.9 μeqL-1. Specific conductances and alkalinity concentrations were substantially higher in lakes in the central and northernRocky Mountains parks (Grand Teton, Yellowstone, and GlacierNational Parks), probably due to the prevalence of more reactivebedrock types. Regional patterns in lake concentrations of NO3 and SO4 were similar to regional patterns in NO3 and SO4 concentrations in precipitation, suggestingthat the lakes are showing a response to atmospheric deposition.Concentrations of NO3 were particularly high in Rocky Mountain National Park, where some ecosystems appear to be undergoing nitrogen saturation.

Methane emissions from western Canadian peatland lakes: assessing interactive effects of groundwater connectivity and permafrost thaw

NASA Astrophysics Data System (ADS)

Kuhn, M. A.; Riechert, C.; Estop Aragones, C.; Broder, T.; Bastviken, D.; Knorr, K. H.; Olefeldt, D.

2017-12-01

Rising temperatures and the submergence of recently thawed permafrost into lakes has been identified as a major driver of methane (CH4) emissions in northern regions. Lakes on the vast Taiga Plains in western Canada represent a vital unknown with respect to CH4 fluxes and their sensitivity to permafrost thaw. The Taiga Plains has several characteristics that could influence magnitude and controls on lake CH4 emissions in comparison to other regions, including high soil organic carbon stores, distinct permafrost history, and complex groundwater interactions that influence availability of terminal electron acceptor concentrations among lakes. The goal of this research is to describe the similarities and differences in processes governing lake CH4 emissions between western Canada and other northern regions. We carried out biweekly diffusive and ebullition flux measurements and monitored sediment redox profiles from two lakes near the border between Alberta and the Northwest Territories. The two lakes differ in contributions of surface water and groundwater inputs, respectively. Floating chamber-based fluxes were measured leading from the edges to the centers of the lakes from ice-out in early May until ice-cover in the fall. Preliminary redox profile analyses suggest the groundwater-fed lake has extremely high concentrations of sulfides (>200 µmol L-1) down to a depth of 30 cm, while the surface water lake has little to no sulfide, but high concentrations of reduced iron (>200 µmol L-1 ). Despite high sulfide concentrations in the sediments, the groundwater-fed lake had generally higher diffusive fluxes compared to the surface water lake, but there were no differences between the center and along the actively collapsing thermokarst edges. However, ebullition fluxes were highest from a recently thawed lake edge compared to the center of the lake and stable, non-thaw influenced edges. The results of this project will help improve current regional CH4 models by

Spatial distribution and temporal development of high-mountain lakes in western Austria

NASA Astrophysics Data System (ADS)

Merkl, Sarah; Emmer, Adam; Mergili, Martin

2015-04-01

Glacierized high-mountain environments are characterized by active morphodynamics, favouring the rapid appearance and disappearance of lakes. On the one hand, such lakes indicate high-mountain environmental changes such as the retreat of glaciers. On the other hand, they are sometimes susceptible to sudden drainage, leading to glacial lake outburst floods (GLOFs) putting the downstream population at risk. Whilst high-mountain lakes have been intensively studied in the Himalayas, the Pamir, the Andes or the Western Alps, this is not the case for the Eastern Alps. A particular research gap, which is attacked with the present work, concerns the western part of Austria. We consider a study area of approx. 6,140 km², covering the central Alps over most of the province of Tyrol and part of the province of Salzburg. All lakes ≥250 m² located higher than 2000 m asl are mapped from high-resolution Google Earth imagery and orthophotos. The lakes are organized into seven classes: (i) ice-dammed; near-glacial (ii) moraine-dammed and (iii) bedrock-dammed; (iv) moraine-dammed and (v) bedrock-dammed distant to the recent glaciers; (vi) landslide-dammed; (vii) anthropogenic. The temporal development of selected lakes is investigated in detail, using aerial photographs dating back to the 1950s. 1045 lakes are identified in the study area. Only eight lakes are ice-dammed (i). One third of all lakes is located in the immediate vicinity of recent glacier tongues, half of them impounded by moraine (ii), half of them by bedrock (iii). Two thirds of all lakes are impounded by features (either moraines or bedrock) shaped by LIA or Pleistocenic glaciers at some distance to the present glacier tongues (iv and v). Only one landslide-dammed lake (vi) is identified in the study area, whilst 21 lakes are of anthropogenic origin (vii). 72% of all lakes are found at 2250-2750 m asl whilst less than 2% are found above 3000 m asl. The ratio of rock-dammed lakes increases with increasing

Acidophilic Halophilic Microorganisms in Fluid Inclusions in Halite from Lake Magic, Western Australia

PubMed Central

Conner, Amber J.

2013-01-01

Abstract Lake Magic is one of the most extreme of hundreds of ephemeral acid-saline lakes in southern Western Australia. It has pH as low as 1.7, salinity as high as 32% total dissolved solids, temperatures ranging from 0°C to 50°C, and an unusually complex aqueous composition. Optical petrography, UV-vis petrography, and laser Raman spectrometry were used to detect microorganisms and organic compounds within primary fluid inclusions in modern bedded halite from Lake Magic. Rare prokaryotes appear as 1–3 μm, bright cocci that fluoresce green with UV-vis illumination. Dimpled, 5–7 μm yellow spherules that fluoresce blue with UV-vis illumination are interpreted as Dunaliella algae. Yellow-orange beta-carotene crystals, globules, and coatings are characterized by orange-red fluorescence and three distinct Raman peaks. Because acid saline lakes are good Mars analogues, the documentation of prokaryotes, eukaryotes, and organic compounds preserved in the halite here has implications for the search for life on Mars. Missions to Mars should incorporate such in situ optical and chemical examination of martian evaporites for possible microorganisms and/or organic compounds in fluid inclusions. Key Words: Acid—Extremophiles—Western Australia—Fluid inclusions—Lake Magic—Dunaliella. Astrobiology 13, 850–860. PMID:23971647

Estimation of invertebrate production from patterns of fish predation in western Lake Superior

USGS Publications Warehouse

Johnson, Timothy B.; Mason, Doran M.; Bronte, Charles R.; Kitchell, James F.

1998-01-01

We used bioenergetic models for lake herring Coregonus artedi, bloater Coregonus hoyi, and rainbow smelt Osmerus mordax to estimate consumption of zooplankton,Mysis, andDiporeia in western Lake Superior for selected years between 1978 and 1995. Total invertebrate biomass consumed yearly ranged from 2.5 to 38 g/m2 with nearly 40% consumed between August and October in all years. Copepod zooplankton represented the largest proportion of biomass collectively consumed by the three species (81%), although rainbow smelt consumed almost twice as much Mysis as zooplankton. Growth efficiency was highest for rainbow smelt (3.84–16.64%) and lower for the coregonids (1.91–12.26%). In the absence of quantitative secondary production values, we suggest our estimates of predatory demand provide a conservative range of the minimum invertebrate production in western Lake Superior during the past 20 years.

Phosphorus availability in Western Lake Erie Basin drainage waters: legacy evidence across spatial scales

USDA-ARS?s Scientific Manuscript database

The Western Lake Erie Basin (WLEB) was inundated with precipitation during June and July 2015 (2-3× greater than historical averages), which led to significant nutrient loading and the largest in-lake algal bloom on record. Using discharge and concentration data from three spatial scales (0.09 km2 t...

Environmental controls on soil organic carbon and nitrogen stocks in the high-altitude arid western Qinghai-Tibetan Plateau permafrost region

NASA Astrophysics Data System (ADS)

Wu, Xiaodong; Zhao, Lin; Fang, Hongbing; Zhao, Yuguo; Smoak, Joseph M.; Pang, Qiangqiang; Ding, Yongjian

2016-01-01

While permafrost in the circum-Artic has great influence on soil organic carbon (SOC) and total nitrogen (TN) stocks, this might not be the case in low-latitude arid permafrost regions. We test this hypothesis in the western Qinghai-Tibetan Plateau (QTP) permafrost region. Fifty-nine soil profiles were analyzed to examine the SOC and TN distribution and the controlling factors in western QTP, which is a desert steppe ecoregion. Mean stocks of SOC (5.29 kg m-2) and TN (0.56 kg m-2) for the top 200 cm in this area were lower than those of the east QTP and circum-Arctic regions. The SOC and TN stocks under vegetative cover with permafrost conditions were significantly higher than those of desert conditions. The SOC and TN stocks for the layers of different depths were related to the content of clay, silt, and moisture. Although the active layer thickness (ALT) had a significant negative correlation to soil moisture, the ALT explained little or no variance in the SOC and TN stocks. The results showed that in the vast permafrost regions of the western QTP, the SOC and TN stocks are very low, and the main controlling factors for the SOC and TN are soil texture, moisture, and vegetation type. The SOC pool in this area may not be as vulnerable to degradation associated with climate warming and thus not emit greenhouse gases at the same rate as other permafrost regions. The different response of the SOC in this region should be considered in carbon cycling models.

SPATIAL PATTERNS IN ASSEMBLAGE STRUCTURES OF PELAGIC FORAGE FISH AND ZOOPLANKTON IN WESTERN LAKE SUPERIOR

EPA Science Inventory

This manuscript reports on the spatial distribution of zooplankton and forage fish in western Lake Superior. Fish and zooplankton assemblages are shown to differ substantially in abundance and size structure both between the open lake and nearshore regions and between two differe...

Hydroacoustic estimates of abundance and spatial distribution of pelagic prey fishes in western Lake Superior

USGS Publications Warehouse

Mason, Doran M.; Johnson, Timothy B.; Harvey, Chris J.; Kitchell, James F.; Schram, Stephen T.; Bronte, Charles R.; Hoff, Michael H.; Lozano, Stephen J.; Trebitz, Anett S.; Schreiner, Donald R.; Lamon, E. Conrad; Hrabik, Thomas R.

2005-01-01

Lake herring (Coregonus artedi) and rainbow smelt (Osmerus mordax) are a valuable prey resource for the recovering lake trout (Salvelinus namaycush) in Lake Superior. However, prey biomass may be insufficient to support the current predator demand. In August 1997, we assessed the abundance and spatial distribution of pelagic coregonines and rainbow smelt in western Lake Superior by combining a 120 kHz split beam acoustics system with midwater trawls. Coregonines comprised the majority of the midwater trawl catches and the length distributions for trawl caught fish coincided with estimated sizes of acoustic targets. Overall mean pelagic prey fish biomass was 15.56 kg ha−1 with the greatest fish biomass occurring in the Apostle Islands region (27.98 kg ha−1), followed by the Duluth Minnesota region (20.22 kg ha−1), and with the lowest biomass occurring in the open waters of western Lake Superior (9.46 kg ha−1). Biomass estimates from hydroacoustics were typically 2–134 times greater than estimates derived from spring bottom trawl surveys. Prey fish biomass for Lake Superior is about order of magnitude less than acoustic estimates for Lakes Michigan and Ontario. Discrepancies observed between bioenergetics-based estimates of predator consumption of coregonines and earlier coregonine biomass estimates may be accounted for by our hydroacoustic estimates.

Diet of the double-crested cormorant in western Lake Erie

USGS Publications Warehouse

Bur, Michael T.; Tinnirello, Sandra L.; Lovell, Charles D.; Tyson, Jeff T.

1999-01-01

Sport and commercial fishing interest groups are concerned about potential impacts double-crested cormorants (Phalacrocorax auritus) may have on fish species. Our objectives for this study were to determine the diet of the cormorant in western Lake Erie and the diet overlap and competition for resources with piscivorous fish, such as walleye (Stizostedion vitreum). The stomach contents of 302 double-crested cormorants collected in western Lake Erie consisted primarily of young-of-the-year gizzard shad (Dorosoma cepedianum), emerald shiner (Notropis atherinoides), and freshwater drum (Aplodinotus grunniens). In the spring, freshwater drum were the most frequently occurring food in the stomachs and constituted the greatest portion of the diet by weight. Young gizzard shad became the most abundant prey and made up the largest percentage of the diet by weight in the stomachs from the end of July through October. Emerald shiners were abundant in the diet during June, September, and October. The fish species that cormorants ate resembled, by proportion, the species mix found in trawl catches. The diets of cormorants and walleyes were similar from July to October with significant overlap. Results from this study suggest impacts of cormorants at current population levels in Lake Erie are not detrimental to sport and commercial fishing. Therefore, control for the purpose of reducing competition for prey fish with walleye is not warranted at this time.

Food of freshwater drum in western Lake Erie

USGS Publications Warehouse

Bur, Michael T.

1982-01-01

The abundance of freshwater drum (Aplodinotus grunniens) suggests they play an important role in the Lake Erie ecosystem. Our analysis of freshwater drum digestive tracts and macrobenthic samples collected from western Lake Erie indicates that drum were selective feeders. Planktonic cladocerans and larval midges (Chironomidae) were the primary prey organisms eaten by drum. Young-of-the-year fed mostly on cladocerans, while yearling and older drum ate both cladocerans and midge larvae. Decapods, pelecypods, and fish were found only in the digestive tracts of drum longer than 250 mm. While the most abundant organisms in benthic samples were cladocerans (ephippial) and oligochaetes (89.5% by number), they constituted less than 1% of the diet. An evaluation of food selectivity, using Ivlev's index of electivity for benthic organisms, indicated that adult drum preferred midges to any other benthic food.

The impacts of climate change and human activities on grassland productivity in Qinghai Province, China

NASA Astrophysics Data System (ADS)

Yin, Fang; Deng, Xiangzheng; Jin, Qin; Yuan, Yongwei; Zhao, Chunhong

2014-03-01

Qinghai Province, which is the source of three major rivers (i.e., Yangtze River, Yellow River and Lancang River) in East Asia, has experienced severe grassland degradation in past decades. The aim of this work was to analyze the impacts of climate change and human activities on grassland ecosystem at different spatial and temporal scales. For this purpose, the regression and residual analysis were used based on the data from remote sensing data and meteorological stations. The results show that the effect of climate change was much greater in the areas exhibiting vigorous vegetation growth. The grassland degradation was strongly correlated with the climate factors in the study area except Haixi Prefecture. Temporal and spatial heterogeneity in the quality of grassland were also detected, which was probably mainly because of the effects of human activities. In the 1980s, human activities and grassland vegetation growth were in equilibrium, which means the influence of human activities was in balance with that of climate change. However, in the 1990s, significant grassland degradation linked to human activities was observed, primarily in the Three-River Headwaters Region. Since the 21st century, this adverse trend continued in the Qinghai Lake area and near the northern provincial boundaries, opposite to what were observed in the eastern part of study. These results are consistent with the currently status of grassland degradation in Qinghai Province, which could serve as a basis for the local grassland management and restoration programs.

Occurrence of zebra mussels in near-shore areas of western Lake Erie

USGS Publications Warehouse

Custer, Christine M.; Custer, T.W.

1997-01-01

Zebra mussels (Dreissena polymorpha) invaded the Great Lakes in the mid-1980s and quickly reached high densities. The objective of this study was to determine current consumption of zebra mussels by waterfowl in the Great Lakes region. Feeding Lesser Scaups (Aythya affinis), Greater Scaups (A. marila), Canvasbacks (A. valisineria), Redheads (A. americana), Buffleheads (Bucephala albeola) and Common Goldeneyes (B. clangula) were collected in western Lake Erie and in Lake St. Clair between fall and spring, 1992-1993 to determine food habits. All 10 Redheads, 97% of Lesser Scaups, 83% of Goldeneyes, 60% of Buffleheads and 9% of Canvasbacks contained one or more zebra mussels in their upper gastrointestinal tracts. The aggregate percent of zebra mussels in the diet of Lesser Scaups was higher in Lake Erie (98.6%) than in Lake St. Clair (54.4%). Zebra mussels, (aggregate percent) dominated the diet of Common Goldeneyes (79.2%) but not in Buffleheads (23.5%), Redheads (21%) or Canvasbacks (9%). Lesser Scaups from Lake Erie fed on larger zebra mussels ( = 10.7 i?? 0.66 mm SE) than did Lesser Scaups from Lake St. Clair ( = 4.4 i?? 0.22 mm). Lesser Scaups, Buffleheads and Common Goldeneyes from Lake Erie consumed zebra mussels of similar size.

Hydrogeological features conditioning trophic levels of quarry lakes in western Po plain (north-western Italy)

NASA Astrophysics Data System (ADS)

De Luca, Domenico Antonio; Castagna, Sara; Lasagna, Manuela

2013-04-01

Quarry lakes occur in plains areas due to the extraction of alluvial sand and gravel used for grout and concrete in the construction industry. Excavation depths can reach and intersect the groundwater surface, thus creating a lake. Because of the need to optimize efficiency, the number of active open pit mines has increased in recent years; consequently, the global number of pit lakes will increase in coming decades (Castendyk and Eary 2009; Klapper and Geller 2001; Castro and Moore 2000). Similar to natural lakes, pit lakes are subject to eutrophication process, both during and after quarrying activity; during mining activity, the eutrophic level is strongly controlled by the excavation method. In the Piedmont territory (north-western Italy) there are 70 active quarry lakes, corresponding to approximately 0.1% of the entire plain area. Quarry lakes, located primarily along the main rivers occur in alluvial deposits of the plain area and have average depths between 20 and 30 m (maximum of 60 m deep) and surface areas between 3 and 30 hectares (Castagna 2008). The present study describes the trophic status of 23 active quarry lakes in the Piedmont plain that were evaluated by applying classifications from scientific literature. Currently, the majority of the studied quarry lakes may be defined as mesotrophic or eutrophic according to the trophic state classifications. Based on historic data, lake trophic levels have increased over time, during active mining. At the end of mining activity, further deterioration of water quality was expected, especially for smaller lakes with minimal oxygen stratification and higher levels of nutrients and algal growth. In addition, the paper focuses on the pit lake water quality and pit dimension; From an environmental perspective the excavation of quarry lakes with an appreciable size will likely result in a better safeguard of water quality and enhanced possibilities for lake end use after the cessation of mining. Piedmont quarry

Microplastic Abundance and Composition in Western Lake Superior As Determined via Microscopy, Pyr-GC/MS, and FTIR.

PubMed

Hendrickson, Erik; Minor, Elizabeth C; Schreiner, Kathryn

2018-02-20

While plastic pollution in marine and freshwater systems is an active area of research, there is not yet an in-depth understanding of the distributions, chemical compositions, and fates of plastics in aquatic environments. In this study, the magnitude, distribution, and common polymers of microplastic pollution in surface waters in western Lake Superior are determined. Analytical methodology, including estimates of ambient contamination during sample collection and processing, are described and employed. Microscopy, pyrolysis-gas chromatography/mass spectrometry (Pyr-GC/MS), and Fourier transform infrared spectroscopy (FTIR) were used to quantify and identify microplastic particles. In surface waters, fibers were the most frequently observed morphology, and, based upon PyGC/MS analysis,  polyvinyl chloride was the most frequently observed polymer, followed by polypropylene and polyethylene. The most common polymer identified by FTIR was polyethylene. Despite the low human population in Lake Superior's watershed, microplastic particles (particularly fibers, fragments, and films) were identified in western-lake surface waters at levels comparable to average values reported in studies within Lake Michigan, the North Atlantic Ocean, and the South Pacific Ocean. This study provides insight into the magnitude of microplastic pollution in western Lake Superior, and describes in detail methodology to improve future microplastics studies in aquatic systems.

The effect of mayfly (Hexagenia spp.) burrowing activity on sediment oxygen demand in western Lake Erie

USGS Publications Warehouse

Edwards, William J.; Soster, Frederick M.; Matisoff, Gerald; Schloesser, Donald W.

2009-01-01

Previous studies support the hypothesis that large numbers of infaunal burrow-irrigating organisms in the western basin of Lake Erie may increase significantly the sediment oxygen demand, thus enhancing the rate of hypolimnetic oxygen depletion. We conducted laboratory experiments to quantify burrow oxygen dynamics and increased oxygen demand resulting from burrow irrigation using two different year classes of Hexagenia spp. nymphs from western Lake Erie during summer, 2006. Using oxygen microelectrodes and hot film anemometry, we simultaneously determined oxygen concentrations and burrow water flow velocities. Burrow oxygen depletion rates ranged from 21.7 mg/nymph/mo for 15 mm nymphs at 23 °C to 240.7 mg/nymph/mo for 23 mm nymphs at 13 °C. Sealed microcosm experiments demonstrated that mayflies increase the rate of oxygen depletion by 2-5 times that of controls, depending on size of nymph and water temperature, with colder waters having greater impact. At natural population densities, nymph pumping activity increased total sediment oxygen demand 0.3-2.5 times compared to sediments with no mayflies and accounted for 22-71% of the total sediment oxygen demand. Extrapolating laboratory results to the natural system suggest that Hexagenia spp. populations may exert a significant control on oxygen depletion during intermittent stratification. This finding may help explain some of the fluctuations in Hexagenia spp. population densities in western Lake Erie and suggests that mayflies, by causing their own population collapse irrespective of other environmental conditions, may need longer term averages when used as a bio-indicator of the success of pollution-abatement programs in western Lake Erie and possibly throughout the Great Lakes.

A 16-ka oxygen-isotope record from Genggahai Lake on the northeastern Qinghai-Tibetan Plateau: Hydroclimatic evolution and changes in atmospheric circulation

NASA Astrophysics Data System (ADS)

Qiang, Mingrui; Song, Lei; Jin, Yanxiang; Li, Yuan; Liu, Li; Zhang, Jiawu; Zhao, Yan; Chen, Fahu

2017-04-01

Moisture source history and changes in atmospheric circulation are the most important attributes for portraying past climate changes and for estimating possible future trends. However, few climate records reflecting these attributes are available from the marginal zones of the Asian summer monsoon. Here, we present a record of the oxygen isotopic composition of authigenic carbonates (δ18Ocarb) of sequential sediments from Genggahai Lake in the northeastern Qinghai-Tibetan Plateau (QTP). Isotopic analyses were performed on the fine-grained carbonate fraction (<38 μm), mollusc shells, and stem encrustations from submerged plants. The stratigraphic variations of the δ18O record from the different carbonate components exhibit a remarkably similar pattern, probably reflecting the fact that δ18Ocarb variability was controlled primarily by changes in the oxygen isotopic composition of the lake water (δ18OLW). Disequilibrium effects and water temperature are precluded as major factors affecting the δ18Ocarb variations. Genggahai Lake is hydrologically open and characterized by a rapid discharge rate, as indicated by analysis of the hydrological setting of the lake system and by the observed significant positive correlation between δ18OLW and the oxygen isotopic composition of the inflowing water (δ18OI). Under such hydrological conditions, we argue that the isotopic signals of different moisture sources should be reflected in the carbonate isotopic composition. Furthermore, placing the δ18Ocarb record in the context of regional palaeoclimate archives, we found that the isotopic signals, particularly the negative shifts from the average values, cannot be interpreted consistently, despite a process of evaporative enrichment at the lake surface. During the early- to mid-Holocene, low δ18Ocarb values during 10.6-9.4 and 7.4-6.3 ka were associated with higher lake levels, and thus the record may have been significantly affected by a strengthened Asian summer monsoon

Great Lakes transport of western coal: economic and technical analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elste, V.H.; Scher, R.M

1978-04-01

A comprehensive investigation of coal transportation from western mines via railroad unit trains plus water transport on the Great Lakes covers in detail: the design of coal colliers for the Great Lakes as limited in size by the Poe lock at Sault Ste. Marie or by river destinations; effects of ice freezing on the lakes or on the coal cargo; problems of designing for alternative transport of taconite pellets; the economic effects of variations in ship characteristics; the effect of fuel price and of operation through the winter; economic comparison of transport alternatives for various pairs of sources and destinations;more » the advantage (vs. a slurry pipeline) of being able to expand on a unit-by-unit basis; and that the rail-water route is lowest in cost for all destinations on the Great Lakes east of Detroit, but direct unit-train service to Chicago is either equal or superior to the rail-water combination. (''A unitrain operating on level track is a most energy-efficient producer of transportation and only an extremely large vessel can approach or equal this performance'').« less

Changing climate in the Lake Superior region: a case study of the June 2012 flood and its effects on the western-lake water column

NASA Astrophysics Data System (ADS)

Minor, E. C.; Forsman, B.; Guildford, S. J.

2013-12-01

In Lake Superior, the world's largest freshwater lake by area, we are seeing annual surface-water temperature increases outpacing those of the overlying atmosphere. We are also seeing ever earlier onsets of water-column stratification (in data sets from the mid-1980s to the present). In Minnesota, including the Lake Superior watershed, precipitation patterns are also shifting toward fewer and more extreme storm events, such as the June 2012 solstice flood, which impacted the western Lake Superior basin. We are interested in how such climatological changes will affect nutrient and carbon biogeochemistry in Lake Superior. The lake is currently an oligotrophic system exhibiting light limitation of primary production in winter and spring, with summer primary production generally limited by phosphorus and sometimes co-limited by iron. Analyses in the western arm of Lake Superior showed that the June 2012 flood brought large amounts of sediment and colored dissolved organic matter (CDOM) from the watershed into the lake. There was initially a ~50-fold spike in the total phosphorus concentrations (and a 5 fold spike in soluble reactive phosphorus) in flood-impacted waters. This disappeared rapidly, in large part due to sediment settling and did not lead to an increase in chlorophyll concentrations at monitored sampling sites. Instead, lake phytoplankton appeared light limited by a surface lens of warm water enriched in CDOM that persisted for over a month after the flood event itself. Our observations highlight the need for continuing research on these complex in-lake processes in order to make accurate predictions about longer term impacts of these large episodic inputs in CDOM, sediment, and nutrient loading.

Contrasting response of coexisting plant's water-use patterns to experimental precipitation manipulation in an alpine grassland community of Qinghai Lake watershed, China.

PubMed

Wu, Huawu; Li, Jing; Li, Xiao-Yan; He, Bin; Liu, Jinzhao; Jiang, Zhiyun; Zhang, Cicheng

2018-01-01

Understanding species-specific changes in water-use patterns under recent climate scenarios is necessary to predict accurately the responses of seasonally dry ecosystems to future climate. In this study, we conducted a precipitation manipulation experiment to investigate the changes in water-use patterns of two coexisting species (Achnatherum splendens and Allium tanguticum) to alterations in soil water content (SWC) resulting from increased and decreased rainfall treatments. The results showed that the leaf water potential (Ψ) of A. splendens and A. tanguticum responded to changes in shallow and middle SWC at both the control and treatment plots. However, A. splendens proportionally extracted water from the shallow soil layer (0-10cm) when it was available but shifted to absorbing deep soil water (30-60 cm) during drought. By contrast, the A. tanguticum did not differ significantly in uptake depth between treatment and control plots but entirely depended on water from shallow soil layers. The flexible water-use patterns of A.splendens may be a key factor facilitating its dominance and it better acclimates the recent climate change in the alpine grassland community around Qinghai Lake.

Spatiotemporal patterns of high-mountain lakes and related hazards in western Austria

NASA Astrophysics Data System (ADS)

Emmer, Adam; Merkl, Sarah; Mergili, Martin

2015-10-01

Climate-induced environmental changes are triggering the dynamic evolution of high-mountain lakes worldwide, a phenomenon that has to be monitored in terms of lake outburst hazards. We analyzed the spatial distribution and recent temporal development of high-mountain lakes in a study area of 6139 km2, covering the central European Alps over most of the province of Tyrol and part of the province of Salzburg in western Austria. We identified 1024 natural lakes. While eight lakes are ice-dammed, one-third of all lakes are located in the immediate vicinity of recent glacier tongues, half of them impounded by moraines, half by bedrock. Two-thirds of all lakes are apparently related to LIA or earlier glaciations. One landslide-dammed lake was identified in the study area. The evolution of nine selected (pro)glacial lakes was analyzed in detail, using multitemporal remotely sensed images and field reconnaissance. Considerable glacier retreat led to significant lake growth at four localities, two lakes experienced stagnant or slightly negative areal trends, one lake experienced a more significant negative areal trend, and two lakes drained completely during the investigation period. We further (i) analyzed the susceptibility of selected lakes to glacial lake outburst floods (GLOFs), using two different methods; (ii) identified potential triggers and mechanisms of GLOFs; (iii) calculated possible flood magnitudes for predefined flood scenarios for a subset of the lakes; and (iv) delineated potentially impacted areas. We distinguished three phases of development of bedrock-dammed lakes: (a) a proglacial, (b) a glacier-detached, and (c) a nonglacial phase. The dynamics - and also the susceptibility of a lake to GLOFs - decrease substantially from (a) to (c). Lakes in the stages (a) and (b) are less prominent in our study area, compared to other glacierized high-mountain regions, leading us to the conclusion that (i) the current threat to the population by GLOFs is lower but

Cross shore transport by wind-driven turbidity plumes in western Lake Superior*

EPA Science Inventory

Turbidity plumes frequently occur in the western arm of Lake Superior and may represent a significant cross shelf transport mechanism for sediment, nutrient and biota. We characterize a plume that formed in late April 2016 using observations from in situ sensors and remote sensin...

Factors related to northern goshawk landscape use in the western Great Lakes region

USGS Publications Warehouse

Bruggeman, Jason E.; Andersen, David E.; Woodford, James E.

2014-01-01

Northern Goshawks (Accipiter gentilis) are a species of special conservation concern in the western Great Lakes bioregion and elsewhere in North America, and exhibit landscape-scale spatial use patterns. However, little information exists about Northern Goshawk habitat relations at broad spatial extents, as most existing published information comes from a few locations of relatively small spatial extent and, in some cases, short durations. We used an information-theoretic approach to evaluate competing hypotheses regarding factors (forest canopy cover, successional stage, and heights of the canopy top and base) related to odds of Northern Goshawk landscape use throughout the western Great Lakes bioregion based on an occupancy survey completed in 2008 (Bruggeman et al. 2011). We also combined these data with historical data of Northern Goshawk nest locations in the bioregion from 1979–2006 to evaluate the same competing hypotheses to elucidate long-term trends in use. The odds of Northern Goshawk use in 2008, and from 1979–2008, were positively correlated with average percent canopy cover. In the best-approximating models developed using 1979–2008 data, the odds of landscape use were positively correlated with the percentages of the landscape having canopy heights between 10 m and 25 m, and 25 m and 50 m, and the amount of variability in canopy base height. Also, the odds of landscape use were negatively correlated with the average height at the canopy base. Our results suggest multiple habitat factors were related to Northern Goshawk landscape-scale habitat use, similar to habitat use described at smaller spatial scales in the western Great Lakes bioregion and in western North America and Europe.

The Fossil Fauna of the Islands Region of Western Lake Erie.

ERIC Educational Resources Information Center

Bowe, Lulu M., Comp.

The islands of western Lake Erie are rock-bound isles that abound in rocky outcrops and quarries. The rocks of these islands are of two distinct types, Silurian dolomites and Devonian limestones. The dolomites, exposed in the Bass Islands and Sister Islands are virtually devoid of fossils. Conversely, the limestones of Johnson Island, Marblehead,…

Long-term ecosystem monitoring and assessment of the Detroit River and Western Lake Erie.

PubMed

Hartig, J H; Zarull, M A; Ciborowski, J J H; Gannon, J E; Wilke, E; Norwood, G; Vincent, A N

2009-11-01

Over 35 years of US and Canadian pollution prevention and control efforts have led to substantial improvements in environmental quality of the Detroit River and western Lake Erie. However, the available information also shows that much remains to be done. Improvements in environmental quality have resulted in significant ecological recovery, including increasing populations of bald eagles (Haliaeetus leucocephalus), peregrine falcons (Falco columbarius), lake sturgeon (Acipenser fulvescens), lake whitefish (Coregonus clupeaformis), walleye (Sander vitreus), and burrowing mayflies (Hexagenia spp.). Although this recovery is remarkable, many challenges remain, including population growth, transportation expansion, and land use changes; nonpoint source pollution; toxic substances contamination; habitat loss and degradation; introduction of exotic species; and greenhouse gases and global warming. Research/monitoring must be sustained for effective management. Priority research and monitoring needs include: demonstrating and quantifying cause-effect relationships; establishing quantitative endpoints and desired future states; determining cumulative impacts and how indicators relate; improving modeling and prediction; prioritizing geographic areas for protection and restoration; and fostering long-term monitoring for adaptive management. Key management agencies, universities, and environmental and conservation organizations should pool resources and undertake comprehensive and integrative assessments of the health of the Detroit River and western Lake Erie at least every 5 years to practice adaptive management for long-term sustainability.

Black carbon aerosol characterization in a remote area of Qinghai-Tibetan Plateau, western China.

PubMed

Wang, Qiyuan; Schwarz, J P; Cao, Junji; Gao, Rushan; Fahey, D W; Hu, Tafeng; Huang, R-J; Han, Yongming; Shen, Zhenxing

2014-05-01

The concentrations, size distributions, and mixing states of refractory black carbon (rBC) aerosols were measured with a ground-based Single Particle Soot Photometer (SP2), and aerosol absorption was measured with an Aethalometer at Qinghai Lake (QHL), a rural area in the Northeastern Tibetan Plateau of China in October 2011. The area was not pristine, with an average rBC mass concentration of 0.36 μg STP-m(-3) during the two-week campaign period. The rBC concentration peaked at night and reached the minimal in the afternoon. This diurnal cycle of concentration is negatively correlated with the mixed layer depth and ventilation. When air masses from the west of QHL were sampled in late afternoon to early evening, the average rBC concentration of 0.21 μg STP-m(-3) was observed, representing the rBC level in a larger Tibetan Plateau region because of the highest mixed layer depth. A lognormal primary mode with mass median diameter (MMD) of ~175 nm, and a small secondary lognormal mode with MMD of 470-500 nm of rBC were observed. Relative reduction in the secondary mode during a snow event supports recent work that suggested size dependent removal of rBC by precipitation. About 50% of the observed rBC cores were identified as thickly coated by non-BC material. A comparison of the Aethalometer and SP2 measurements suggests that non-BC species significantly affect the Aethalometer measurements in this region. A scaling factor for the Aethalometer data at a wavelength of 880 nm is therefore calculated based on the measurements, which may be used to correct other Aethalometer datasets collected in this region for a more accurate estimate of the rBC loading. The results present here significantly improve our understanding of the characteristics of rBC aerosol in the less studied Tibetan Plateau region and further highlight the size dependent removal of BC via precipitation. Copyright © 2014 Elsevier B.V. All rights reserved.

Predation of the zebra mussel (Dreissena polymorpha) by freshwater drum in western Lake Erie

USGS Publications Warehouse

French, John R. P.; Bur, Michael T.; Nalepa, Thomas F.; Schloesser, Donald W.

1992-01-01

Environmental and economic problems associated with the colonization of zebra mussels (Dreissena polymorpha) in western Lake Erie created a need to investigate control mechanisms. Predation by fishes is one potential means of control, but predation on zebra mussels by native fishes in Lake Erie is unknown. The freshwater drum (Aplodinotus grunniens) is the most likely fish predator since it is the only fish with pharyngeal teeth capable of crushing mollusk shells. In 1990, freshwater drum were collected in western Lake Erie from 9 sites near rocky reefs and 13 sites with silt or sand bottoms, and gut contents were examined. Predation on zebra mussels increased as drum size increased. Small drum (200-249 mm in length) fed mainly on dipterans, amphipods, and small fish; small zebra mussels (375 mm in length) fed almost exclusively on zebra mussels (seasons and locations combined). The smallest drum capable of crushing zebra mussel shells was 265 mm. Since freshwater drum over 375 mm feed heavily on zebra mussels, they may become a possible biological control mechanism for mussels in portions of North America.

Distribution and abundance of the polychaete, Manayunkia speciosa Leidy, in western Lake Erie

USGS Publications Warehouse

Hiltunen, Jarl K.

1965-01-01

The abundance and distribution of the freshwater polychaete, Manayunkia speciosa, in 1961, are described for western Lake Erie. Previous records reveal that the species has either been generally overlooked or presently its numbers have greatly increased in the area considered.

Seperating Long-term Hydrological Loading and Tectonic Deformation Observed with Multi-temporal SAR Interferometry and GPS in Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

LI, G.; Lin, H.

2014-12-01

From 2000 till present, most endorheic lakes in Tibetan plateau experienced quick increasing. Several largest lakes, gathered several meters depth water during one decade. Such massive mass increasing will lead to elastic and visco-elastic deformation of the ground. Qinghai-Tibetan Plateau is one the most active tectonic places in the world; monitoring its ground deformation is essential, when loading effect is a nuisance item. Due to the sparse distribution of GPS sites and most are roving sites, it is hard to distinguish tectonic component from mass loading effect. In this research we took Selin Co Lake located at Nujiang-Bangoin suture zone and evaluated long time ground deformation at hundred kilometers scale by multi-temporal SAR interferometry and simulate the ground deformation by loading history evaluated by multi mission satellite altimetry and optical images observation. At Nujiang-Bangoin suture zone, where GPS presented the maximum ground subsidence in Qinghai-Tibetan Plateau of 3.6mm/a which was found at the shore of Selin Co Lake from 1999 to 2011, when it experienced water level increasing of 0.7m/a. A model of elastic plate lying over Newtonian viscous half-space matches well with the results of multi-temporal SAR interferometry and GPS observations. We concluded that near Selin Co Lake area, ground deformation is composed by both tectonic and hydrological loading part. As SAR image coverage is much smaller than tectonic scale, we contribute the deformation detected by InSAR to loading effect. After evaluating and removing the hydrological loading effect, we founds that Nujiang-Bangoin suture zone did not experience quick subsidence, but only limited to 0.5mm/a. Selin Co Lake's quick volume increasing caused 3mm/a subsidence rate to the nearest GPS site. The Second nearest site showed the 1.4mm/a subsidence totally, which were composed by 1.05mm/a hydrological loading effect and the rest was tectonic. We also found that Young's Modulus is the most

Contrasting response of coexisting plant’s water-use patterns to experimental precipitation manipulation in an alpine grassland community of Qinghai Lake watershed, China

PubMed Central

Li, Xiao-Yan; He, Bin; Liu, Jinzhao; Jiang, Zhiyun; Zhang, Cicheng

2018-01-01

Understanding species-specific changes in water-use patterns under recent climate scenarios is necessary to predict accurately the responses of seasonally dry ecosystems to future climate. In this study, we conducted a precipitation manipulation experiment to investigate the changes in water-use patterns of two coexisting species (Achnatherum splendens and Allium tanguticum) to alterations in soil water content (SWC) resulting from increased and decreased rainfall treatments. The results showed that the leaf water potential (Ψ) of A. splendens and A. tanguticum responded to changes in shallow and middle SWC at both the control and treatment plots. However, A. splendens proportionally extracted water from the shallow soil layer (0–10cm) when it was available but shifted to absorbing deep soil water (30–60 cm) during drought. By contrast, the A. tanguticum did not differ significantly in uptake depth between treatment and control plots but entirely depended on water from shallow soil layers. The flexible water-use patterns of A.splendens may be a key factor facilitating its dominance and it better acclimates the recent climate change in the alpine grassland community around Qinghai Lake. PMID:29677195

Temporal variation of energy reserves in mayfly nymphs (Hexagenia spp.) from Lake St. Clair and western Erie

USGS Publications Warehouse

Cavaletto, J.F.; Nalepa, T.F.; Fanslow, D.L.; Schloesser, D.W.

2003-01-01

4. Indicators of potential food (algal fluorescence in the water column and chlorophyll a and chlorophyll a/phaeophytin ratio in sediments) suggest that Hexagenia in Lake St Clair have a food source that is benthic based, especially in early spring, whereas in western Lake Erie nymphs have a food source that is water column based and settles to the lake bottom during late spring and summer.

Predicting geomorphic stability in low-order streams of the western Lake Superior basin

EPA Science Inventory

Width:depth ratios, entrenchment ratios, gradients, and median substrate particle sizes (D50s) were measured in 32 second and third order stream reaches in the western Lake Superior basin, and stream reaches were assigned a Rosgen geomorphic classification. Over 700 measurements ...

Characterization of selected radionuclides in sediment and surface water in Standley Lake, Great Western Reservoir, and Mower Reservoir, Jefferson County, Colorado, 1992

USGS Publications Warehouse

Clow, D.W.; Johncox, D.A.

1995-01-01

Lake sediment and surface water from Standley Lake, Great Western Reservoir, and Mower Reservoir, near Denver, Colorado, were sampled and analyzed for selected radionuclides during August through October, 1992. Sample concentrations were summarized and compared to results from a study conducted in 1983-84. Median plutonium-239,240 (239,240Pu) concentrations in lake-sediment grab samples from Standley Lake, Great Western Reservoir, and Mower Reservoir were 0.037, 0.105, and 0.351 picocuries per gram (pCi/g). The maximum concen- tration of 239,240Pu dissolved in lake water was 0.009 picocuries per liter, substantially below limits suggested by the Colorado Department of Health and the Environment. Dissolved concentrations of gross alpha and uranium isotopes were below National Drinking Water Standards in all water samples. There was no statistically significant difference between 239,240Pu concentration in lake-sediment grab samples collected from Standley Lake in 1983-84 and in 1992; however, there was a small, but statistically significant, difference at Great Western Reservoir (p<0.05). In 1992 at Great Western Reservoir, median 239,240Pu concentrations were 0.040 pCi/g lower than in 1983-84. There was a small, but statistically significant (p<0.05) difference in 239,240Pu concentrations in lake- bottom-sediment cores collected in 1983-84 and in 1992. Measured concentrations tended to be higher in 1983-84 than in 1992. The differences were greatest at concentrations above 1.5 pCi/g; in those samples concentrations were 10 to 30% higher in 1983-84 than in 1992.

Concentrating Solar Power Projects - Qinghai Gonghe 50 MW CSP Plant |

Science.gov Websites

Concentrating Solar Power | NREL Qinghai Gonghe 50 MW CSP Plant Status Date: September 26, 2016 : 50.0 Status: Under development Do you have more information, corrections, or comments? Background Technology: Power tower Status: Under development Country: China City: Gonghe Region: Qinghai Province

Distribution and abundance of freshwater polychaetes, Manayunkia speciosa (Polychaeta), in the Great Lakes with a 70-year case history for western Lake Erie

USGS Publications Warehouse

Schloesser, Don W.

2013-01-01

Manayunkia speciosa has been a taxonomic curiosity for 150 years with little interest until 1977 when it was identified as an intermediate host of a fish parasite (Ceratomyxa shasta) responsible for fish mortalities (e.g., chinook salmon). Manayunkia was first reported in the Great Lakes in 1929. Since its discovery, the taxon has been reported in 50% (20 of 40 studies) of benthos studies published between 1960 and 2007. When found, Manayunkia comprised 2) and Georgian Bay (1790/m2) than in five other areas (mean = 60 to 553/m2) of the lakes. A 70-year history of Manayunkia in western Lake Erie indicates it was not found in 1930, was most abundant in 1961 (mean = 8039, maximum = 67,748/m2), and decreased in successive periods of 1982 (3529, 49,639/m2), 1993 (1876, 25,332/m2), and 2003 (79, 2583/m2). It occurred at 48% of stations in 1961, 58% in 1982, 52% in 1993, and 6% of stations in 2003. In all years, Manayunkia was distributed primarily near the mouth of the Detroit River. Causes for declines in distribution and abundance are unknown, but may be related to pollution-abatement programs that began in the 1970s, and invasion of dreissenid mussels in the late-1980s which contributed to de-eutrophication of western Lake Erie. At present, importance of the long-term decline of Manayunkia in Lake Erie is unknown.

Marine lake ecosystem dynamics illustrate ENSO variation in the tropical western Pacific

PubMed Central

Martin, Laura E; Dawson, Michael N; Bell, Lori J; Colin, Patrick L

2005-01-01

Understanding El Niño/Southern Oscillation (ENSO) and its biological consequences is hindered by a lack of high-resolution, long-term data from the tropical western Pacific. We describe a preliminary, 6 year dataset that shows tightly coupled ENSO-related bio-physical dynamics in a seawater lake in Palau, Micronesia. The lake is more strongly stratified during La Niña than El Niño conditions, temperature anomalies in the lake co-vary strongly with the Niño 3.4 climate index, and the abundance of the dominant member of the pelagic community, an endemic subspecies of zooxanthellate jellyfish, is temperature associated. These results have broad relevance because the lake: (i) illustrates an ENSO signal that is partly obscured in surrounding semi-enclosed lagoon waters and, therefore, (ii) may provide a model system for studying the effects of climate change on community evolution and cnidarian–zooxanthellae symbioses, which (iii) should be traceable throughout the Holocene because the lake harbours a high quality sediment record; the sediment record should (iv) provide a sensitive and regionally unique record of Holocene climate relevant to predicting ENSO responses to future global climate change and, finally, (v) seawater lake ecosystems elsewhere in the Pacific may hold similar potential for past, present, and predictive measurements of climate variation and ecosystem response. PMID:17148349

Marine lake ecosystem dynamics illustrate ENSO variation in the tropical western Pacific.

PubMed

Martin, Laura E; Dawson, Michael N; Bell, Lori J; Colin, Patrick L

2006-03-22

Understanding El Niño/Southern Oscillation (ENSO) and its biological consequences is hindered by a lack of high-resolution, long-term data from the tropical western Pacific. We describe a preliminary, 6 year dataset that shows tightly coupled ENSO-related bio-physical dynamics in a seawater lake in Palau, Micronesia. The lake is more strongly stratified during La Niña than El Niño conditions, temperature anomalies in the lake co-vary strongly with the Niño 3.4 climate index, and the abundance of the dominant member of the pelagic community, an endemic subspecies of zooxanthellate jellyfish, is temperature associated. These results have broad relevance because the lake: (i) illustrates an ENSO signal that is partly obscured in surrounding semi-enclosed lagoon waters and, therefore, (ii) may provide a model system for studying the effects of climate change on community evolution and cnidarian-zooxanthellae symbioses, which (iii) should be traceable throughout the Holocene because the lake harbours a high quality sediment record; the sediment record should (iv) provide a sensitive and regionally unique record of Holocene climate relevant to predicting ENSO responses to future global climate change and, finally, (v) seawater lake ecosystems elsewhere in the Pacific may hold similar potential for past, present, and predictive measurements of climate variation and ecosystem response.

Infection of the walleye, Stizostedion v. vitreum, of western Lake Erie with Bothriocephalus cuspidatus (Cooper)

USGS Publications Warehouse

Wolfert, David R.; Applegate, Vernon C.; Allison, Leonard N.

1967-01-01

In recent years appreciable changes have taken place in the biota and physiochemical conditions in Lake Erie. The accelerated eutrophication of the lake has been accompanied by the near disappearance of several fish species, e.g., blue pike (Stizostedion vitreum glaucum), lake herring (Coregonus artedi), lake trout (Salvelinus namaycush), sauger (Stizostedion canadense), and whitefish (Coregonus clupeaformis). Interest in the biology of the remaining species has increased as means have been sought to preserve their numbers in the lake. This report, which describes the caecal and intestinal parasites of the walleye, Stizostedion vitreum vitreum, is a contribution to the natural history of this fish in western Lake Erie. This study concerns: the type and degree of intestinal parasitic infestations in a single year class of walleyes during their first 3 years of life; seasonal changes in the incidence and maturity of the dominant parasite Bothriocephalus cuspidatus; and the effects of the infestations on the physical condition of the host.

Spatial changes of the evaporation/inflow ratio of lake water deduced from surface water isotopes in Bangongcuo, western Tibet

NASA Astrophysics Data System (ADS)

Wen, R.; Tian, L.; Weng, Y.; Qu, D.

2013-12-01

Oxygen isotope analysis provides a practical approach to understand the regional hydrologic cycle and to reconstruct the paleoclimate and paleoenvironment from lacustrine sediment. The large number of inland lakes on the northern part of the Tibetan Plateau provides the opportunity for this work, and an understanding of the isotope variation of the lake water in the water cycle is vital for this purpose. A water isotope sampling network was set up in the Banggongcuo Lake basin in western Tibet in 2009 that measured precipitation, lake water, and river water. Two years of collecting isotope data, together with AWS observations at the Ngari station in the basin, allowed for a study of lake water isotope variations in the water cycle in narrow Banggongcuo Lake. Observations showed much higher water δ18O in the closed lake due to the strong evaporation fractionation process when compared with local precipitation. An obvious spatial change of lake water δ18O was also found, varying from about -4.9‰ in the east to about +0.9‰ in the west. This spatial change is largely due to the fact that the main river water input to the lake is on the eastern part of the lake, while the lake water evaporates out gradually westward. This phenomenon also matches the spatial change of lake water chemical components. We simulate the gradual evaporation of the lake water using an isotope evaporation fractionation model, in an effort to quantitatively estimate the E/I ratio (evaporation to total lake water inflow) in different parts of the lake. From the observation lake water δ18O, we estimate that the E/I ratio is about 42~60% in the eastern part of the lake and increases to 76~87% in the western part.

Changes in the chemistry of lakes and precipitation in high-elevation national parks in the western United States, 1985–1999

USGS Publications Warehouse

Clow, David W.; Sickman, James O.; Striegl, Robert G.; Krabbenhoft, David P.; Elliott, John G.; Dornblaser, Mark M.; Roth, David A.; Campbell, Donald H.

2003-01-01

High-elevation lakes in the western United States are sensitive to atmospheric deposition of sulfur and nitrogen due to fast hydrologic flushing rates, short growing seasons, an abundance of exposed bedrock, and a lack of well-developed soils. This sensitivity is reflected in the dilute chemistry of the lakes, which was documented in the U.S. Environmental Protection Agency's Western Lake Survey of 1985. Sixty-nine lakes in seven national parks sampled during the 1985 survey were resampled during fall 1999 to investigate possible decadal-scale changes in lake chemistry. In most lakes, SO4 concentrations were slightly lower in 1999 than in 1985, consistent with a regional decrease in precipitation SO4 concentrations and in SO2 emissions in the western United States. Nitrate concentrations also tended to be slightly lower in 1999 than in 1985, in contrast with generally stable or increasing inorganic N deposition in the west. Differences in alkalinity were variable among parks but were relatively consistent within each park. Possible effects of annual and seasonal-scale variations in precipitation amount on lake chemistry were evaluated based on climate data available for the parks and an analysis of climatic effects at two research watersheds with long-term records. Results suggest that rain prior to sampling in 1985 may have caused elevated NO3 in some lakes due to direct runoff of precipitation and flushing of NO3 from alpine soils, which may explain some of the decrease in NO3 concentrations observed in survey lakes.

Remote Sensing and Underwater Glider Observations of a Springtime Plume in Western Lake Superior

EPA Science Inventory

Plumes are commonly observed in satellite imagery of western Lake Superior following storm events, and represent a significant cross-shelf pathway for sediment and other constituents. However, their subsurface extent is poorly understood. This study reports results from plume ob...

Mercury levels, reproduction, and hematology in western grebes from three California Lakes, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elbert, R.A.; Anderson, D.W.

1998-02-01

Twenty-three healthy adult western and Clark`s grebes (Aechmorphorus occidentalis and Aechmorphorus clarkii) were collected at three study sites in California, USA, in 1992: Clear Lake, Lake County; Eagle Lake, Lassen County; and Tule Lake, Siskiyou County. Liver, kidney, breast muscle, and brain were analyzed for total mercury (Hg) concentration (ppm wet weight), and blood was analyzed for various blood parameters. Clear Lake birds had greater Hg concentrations in kidney, breast muscle, and brain than birds from the other two lakes whereas liver concentrations were not statistically different. Average concentrations for Clear Lake birds were 2.74 ppm for liver, 2.06 ppmmore » for kidney, 1.06 ppm for breast muscle, and 0.28 ppm for brain. The tissue levels of kidney, breast muscle, and brain at the other two study sites were one half the levels found at Clear Lake. These mean tissue levels were near, but below, those known to cause adverse effects. When data from all sites were merged, kidney, breast muscle, and brain concentrations are positively correlated to each other. Liver concentrations were not correlated to any other value. Brain Hg concentrations were also negatively correlated to blood potassium and blood phosphorus levels. Kidney Hg levels were positively correlated to percent blood heterophils and negatively correlated to percent eosinophils, suggesting that mercury levels might be affecting immune function. These biomarkers could not be related to any obvious ecological effects.« less

75 FR 65517 - Western Digital Technologies, Inc., Corporate Headquarters/Hard Drive Development Division, Lake...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-25

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-72,949] Western Digital Technologies, Inc., Corporate Headquarters/Hard Drive Development Division, Lake Forest, CA; Notice of... application, I conclude that the claim is of sufficient weight to justify reconsideration of the U.S...

Predicting geomorphic stability in low-order streams of the western Lake Superior basin - Poster

EPA Science Inventory

Width:depth ratios, entrenchment ratios, gradients, and median substrate particle sizes (D50s) were measured in 32 second- and third-order stream reaches in the western Lake Superior basin in 1997-1998. More than 700 measurements of suspended sediment concentration during snowmel...

Model distribution of Silver Chub (Macrhybopsis storeriana) in western Lake Erie

USGS Publications Warehouse

McKenna, James E.; Castiglione, Chris

2014-01-01

Silver Chub (Macrhybopsis storeriana) was once a common forage fish in Lake Erie but has declined greatly since the 1950s. Identification of optimal and marginal habitats would help conserve and manage this species. We developed neural networks to use broad-scale habitat variables to predict abundance classes of Silver Chub in western Lake Erie, where its largest remaining population exists. Model performance was good, particularly for predicting locations of habitat with the potential to support the highest and lowest abundances of this species. Highest abundances are expected in waters >5 m deep; water depth and distance to coastal habitats were important model features. These models provide initial tools to help conserve this species, but their resolution can be improved with additional data and consideration of other ecological factors.

[Evaluation of ecosystem resilience in the regions across Qinghai-Tibet railway based on GIS].

PubMed

Gao, Jiang-bo; Zhao, Zhi-qiang; Li, Shuang-cheng

2008-11-01

Based on GIS technique and the methods of mean-squared deviation weight decision and catastrophe progression, a more clear definition and associated evaluation for ecosystem resilience were given, with a case study in the regions across Qinghai-Tibet railway by using the indices of plant community coverage, species diversity, and biomass. It was shown that the areas with high ecosystem resilience were mainly located in the Qilian Mountain meadow grassland, Huangshui Valley needle-leaved and deciduous broad-leaved forest, and south Tanggula Mountain kobresia swamp meadow, while those with the lowest resilience were in the central part of Qaidam Basin, and the Kunlun Mountains. Most areas in the regions had higher or medium ecosystem resilience, with a trend of that in the south of Kunlun Mountains, the resilience in the north of the railway was lower, while in the east of Qaidam Basin (especially in the Qinghai Lake area), the resilience was lower in the south than in the north of the railway. Through the evaluation of ecosystem resilience, the key issues in the process of ecological resilience could be found, and corresponding effective measures would be pointed out to manage alpine ecosystems. Moreover, combining with the evaluation of vulnerability, scientific basis for regional development could be provided to avoid or mitigate the negative effects of human activities on eco-environment.

Associations between cyanobacteria and indices of secondary production in the western basin of Lake Erie

USGS Publications Warehouse

Larson, James H.; Evans, Mary Anne; Kennedy, Robert J.; Bailey, Sean; Loftin, Keith A.; Laughrey, Zachary; Femmer, Robin; Schaeffer, Jeff; Richardson, William B.; Wynne, Timothy; Nelson, J. C.; Duris, Joseph W.

2018-01-01

Large lakes provide a variety of ecological services to surrounding cities and communities. Many of these services are supported by ecological processes that are threatened by the increasing prevalence of cyanobacterial blooms which occur as aquatic ecosystems experience cultural eutrophication. Over the past 10 yr, Lake Erie experienced cyanobacterial blooms of increasing severity and frequency, which have resulted in impaired drinking water for the surrounding communities. Cyanobacterial blooms may impact ecological processes that support other services, but many of these impacts have not been documented. Secondary production (production of primary consumers) is an important process that supports economically important higher trophic levels. Cyanobacterial blooms may influence secondary production because cyanobacteria are a poor‐quality food resource and cyanotoxins may be harmful to consumers. Over 3 yr at 34 sites across the western basin of Lake Erie, we measured three indices of secondary production that focus on the dominant bivalve taxa: (1) growth of a native unionid mussel, (2) the size of young‐of‐year dreissenid mussels, and (3) the mass of colonizing animals on a Hester‐Dendy sampler. Associations between these indices and cyanobacterial data were estimated to assess whether cyanobacteria are associated with variation in secondary production in the western basin of Lake Erie. The results suggest cyanobacterial abundance alone is only weakly associated with secondary production, but that cyanotoxins have a larger effect on secondary production. Given recurring late‐summer cyanobacterial blooms, this impact on secondary production has the potential to undermine Lake Erie's ability to sustain important ecosystem services.

Effectiveness of a refuge for lake trout in western Lake Superior I: Empirical analysis of past performance

USGS Publications Warehouse

Johnson, Melissa J.; Hansen, Michael J.; Seider, Michael J.

2015-01-01

The Gull Island Shoal Refuge was created in 1976 in response to overfishing of the Lake Trout Salvelinus namaycush population in the Apostle Islands region of western Lake Superior. Our objective was to evaluate effectiveness of the refuge by determining whether Lake Trout abundance, growth, maturity, and mortality differed inside and outside the refuge. We compared abundance of wild and stocked fish captured inside and outside the refuge during spring large-mesh gill-net and summer graded-mesh gill-net surveys. We compared growth and mortality during four periods corresponding to four generations of wild Lake Trout, including the last generation that hatched before the refuge was instituted (sampled in 1981–1984) and three generations that were protected by the refuge (sampled in 1985–1992, 1993–2000, and 2001–2010). Maturity of wild fish inside and outside the refuge was compared only for the latter period (2001–2010) because maturity was not assessed earlier. After the refuge was created, wild Lake Trout abundance increased and stocked Lake Trout abundance decreased. Wild adults and juveniles were more abundant inside than outside the refuge, and stocked adults were less abundant inside than outside the refuge. Growth of wild fish did not differ inside versus outside the refuge before 2001, but wild fish grew faster to a shorter asymptotic length inside than outside the refuge during 2001–2010. Wild fish matured at a similar length but an older age inside than outside the refuge during 2001–2010. Survival of wild fish did not differ inside versus outside the refuge before 1993, but mortality was lower inside than outside the refuge during later periods (1993–2000 and 2001–2010). We conclude that the Gull Island Shoal Refuge enhanced the population growth of wild Lake Trout in the Apostle Islands region and should be retained in the future to sustain conditions that favor population growth.

Pluvial lakes in the Great Basin of the western United States: a view from the outcrop

USGS Publications Warehouse

Reheis, Marith C.; Adams, Kenneth D.; Oviatt, Charles G.; Bacon, Steven N.

2014-01-01

Paleo-lakes in the western United States provide geomorphic and hydrologic records of climate and drainage-basin change at multiple time scales extending back to the Miocene. Recent reviews and studies of paleo-lake records have focused on interpretations of proxies in lake sediment cores from the northern and central parts of the Great Basin. In this review, emphasis is placed on equally important studies of lake history during the past ∼30 years that were derived from outcrop exposures and geomorphology, in some cases combined with cores. Outcrop and core records have different strengths and weaknesses that must be recognized and exploited in the interpretation of paleohydrology and paleoclimate. Outcrops and landforms can yield direct evidence of lake level, facies changes that record details of lake-level fluctuations, and geologic events such as catastrophic floods, drainage-basin changes, and isostatic rebound. Cores can potentially yield continuous records when sampled in stable parts of lake basins and can provide proxies for changes in lake level, water temperature and chemistry, and ecological conditions in the surrounding landscape. However, proxies such as stable isotopes may be influenced by several competing factors the relative effects of which may be difficult to assess, and interpretations may be confounded by geologic events within the drainage basin that were unrecorded or not recognized in a core. The best evidence for documenting absolute lake-level changes lies within the shore, nearshore, and deltaic sediments that were deposited across piedmonts and at the mouths of streams as lake level rose and fell. We review the different shorezone environments and resulting deposits used in such reconstructions and discuss potential estimation errors. Lake-level studies based on deposits and landforms have provided paleohydrologic records ranging from general changes during the past million years to centennial-scale details of fluctuations during the

Metagenomics Reveals a Novel Virophage Population in a Tibetan Mountain Lake

PubMed Central

Oh, Seungdae; Yoo, Dongwan; Liu, Wen-Tso

2016-01-01

Virophages are parasites of giant viruses that infect eukaryotic organisms and may affect the ecology of inland water ecosystems. Despite the potential ecological impact, limited information is available on the distribution, diversity, and hosts of virophages in ecosystems. Metagenomics revealed that virophages were widely distributed in inland waters with various environmental characteristics including salinity and nutrient availability. A novel virophage population was overrepresented in a planktonic microbial community of the Tibetan mountain lake, Lake Qinghai. Our study identified coccolithophores and coccolithovirus-like phycodnaviruses in the same community, which may serve as eukaryotic and viral hosts of the virophage population, respectively. PMID:27151658

Conditions for the return and simulation of the recovery of burrowing mayflies in western Lake Erie

USGS Publications Warehouse

Kolar, Cynthia S.; Hudson, Patrick L.; Savino, Jacqueline F.

1997-01-01

In the 1950s, burrowing mayflies, Hexagenia spp. (H. Limbata and H. Rigida), were virtually eliminated from the western basin of Lake Erie (a 3300 kmA? area) because of eutrophication and pollution. We develop and present a deterministic model for the recolonization of the western basin by Hexagenia to pre-1953 densities. The model was based on the logistic equation describing the population growth of Hexagenia and a presumed competitor, Chironomus (dipteran larvae). Other parameters (immigration, low oxygen, toxic sediments, competition with Chironomus, and fish predation) were then individually added to the logistic model to determine their effect at different growth rates. The logistic model alone predicts 10-41 yr for Hexagenia to recolonize western Lake Erie. Immigration reduced the recolonization time by 2-17 yr. One low-oxygen event during the first 20 yr increased recovery time by 5-17 yr. Contaminated sediments added 5-11 yr to the recolonization time. Competition with Chironomus added 8-19 yr to recovery. Fish predators added 4-47 yr to the time required for recolonization. The full model predicted 48-81 yr for Hexagenia to reach a carrying capacity of approximately 350 nymphs/mA?, or not until around the year 2038 if the model is started in 1990. The model was verified by changing model parameters to those present in 1970, beginning the model in 1970 and running it through 1990. Predicted densities overlapped almost completely with actual estimated densities of Hexagenia nymphs present in the western basin in Lake Erie in 1990. The model suggests that recovery of large aquatic ecosystems may lag substantially behind remediation efforts.

Spatial variation in incidence of mouthpart deformities in larval chironomids (Diptera) from western Lake Erie

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hudson, L.A.; Ciborowski, J.J.H.; Corkum, L.D.

1995-12-31

The major source of contaminants to the sediments of the western basin of Lake Erie is the Detroit River. In order to determine if contaminant levels are reflected in incidences of genotoxicity of benthic invertebrates, the authors examined larvae of chironomids for mouthpart (mentum) deformities. Sediment genotoxicity is indicated when incidence of deformities in susceptible genera exceeds 5%. Samples were collected from three locations along the contaminant gradient extending from the Detroit River along the main shipping channel of the western basin. A composite sample was taken from several central locations in the western basin. Chironomids were hand-picked from ponarmore » grab or box core samples. The heads were mounted, identified to genus and examined for mentum deformities (extra or missing teeth). Chironomus dominated all samples. The incidence of deformities ({+-}SE) in Chironomus was greatest in the Trenton Channel of the Detroit River (7.8 {+-} 2.2%, n = 153), declined to 5.2 {+-} 1.4% (n = 233) in the center of the basin and was the lowest off East Sister Island (1.9 {+-} 0.9%, n = 210). The incidence of deformities was 4.4 {+-} 0.8% (n = 610) at a reference site on the Canadian side of the Detroit River (Crystal Bay). The spatial pattern of chironomid mentum deformities suggests that sediment genotoxicity declines from west to east in western Lake Erie.« less

Toxicity of Cold Lake Blend and Western Canadian Select dilbits to standard aquatic test species

EPA Science Inventory

Dilbits are blends of bitumen and natural gas condensates or crude oils with only limited toxicity data. Two dilbits, Cold Lake Blend and Western Canadian Select, were tested as either unweathered or weathered oils for acute and chronic toxicity to standard freshwater and estuari...

Late Holocene Environmental Reconstruction and Flood Records of Lake Bafa, Western Turkey

NASA Astrophysics Data System (ADS)

Yalamaz, Burak; Bulkan, Özlem; Namık Çaǧatay, M.; Acar, Dursun

2016-04-01

Lake Bafa is a significant inland lake located in the Büyük Menderes River Basin near the Aegean Sea in the horst and graben system of western Turkey. Lake Bafa was part of the ancient Gulf of Latmos that was gradually filled by the prograding sediments of Büyük Menderes River during the Holocene transgression, and resulted in the creation of the Lake in the southern part. The lake is presently located 15 km from the shoreline, 2 m above sea level. It has a maximum depth of 21 m and surface area of 60 km2. We used multi-proxy analyses of a 4.17 m-long core extending back to ca. 2300 years from the central depo centre of the lake. The objectives are to reconstruct the environmental evolution of the Lake Bafa as it changed from a marginal marine to a lacustrine environment, and to investigate the flood records during the past 2300 yrs. The core is composed of three units: an uppermost lacustrine unit, a unit representing marine to lacustrine conditions and a lowermost marine unit. The uppermost lacustrine unit is 1 m-thick, homogenous clayey silt mud layer with relatively high total organic carbon (TOC= 2.5 - 4.5 %), high total inorganic carbon (TIC = 1.8 -4.5 %) and low detrital input (Si, K, Zr, Ti). According to AMS radiocarbon dating, it was deposited over the last 600 yrs under brackish lacustrine conditions. The underlying unit is 2 m-thick, and consists of banded mud layers with relatively low TOC (1.2-4 %) and TIC (1.2-3.5) contents and high detrital input. Its fossil content, with scarce Cardium sp. and Ammonia sp., indicates that it was deposited under brackish water conditions and represents a transition from marine to lacustrine environments. The unit was deposited between ca. 600 and 1750 yrs BP, and includes frequent flood units ranging up to 10 cm-thick fine sand- to clay-bearing coarse silt. The lowermost unit is characterized by relatively high TOC (2-5.5 %), TIC (1.5-3.5 %) contents and high detrital input. With its abundant Cardium sp. and

High Elevation Lakes of the Western US: Are we Studying Systems Recovering from Excess Atmospheric Deposition of Acids and Nutrients?

NASA Astrophysics Data System (ADS)

Sickman, J. O.

2011-12-01

Instrumental records and monitoring of high elevation lakes began in most areas of the western US in the early 1980s. Much effort has been devoted to detecting changes in these aquatic ecosystems resulting from increased atmospheric deposition of acids and nutrients. However, there is growing evidence that thresholds for atmospheric pollutants were crossed much earlier in the 20th Century and that some of the subsequent hydrochemical and ecological changes observed in these lakes may be the result of recovery from earlier atmospheric forcing. We examine responses of high elevation lakes to atmospheric deposition on annual to century timescales using data from a 29-year study of Emerald Lake (Sequoia National Park) and paleolimnological analyses of other high elevation lakes incorporating diatom species analyses and geochemical proxies for fossil-fuel burning. At Emerald Lake, we have observed multiple transitions between nitrogen and phosphorus limitation of phytoplankton, the earliest of which occurred in the beginning of the 1980s and may be the result of reduction in N deposition due to the Clean Air Act. Critical loads analyses incorporating diatom species in lake sediments suggest that thresholds for N deposition were crossed in the period of 1950-1980 in the Rocky Mountains and likely much earlier, 1900-1920, in the Sierra Nevada. Diatom species composition is strongly controlled by acid neutralizing capacity (ANC) in the Sierra Nevada and we have observed a pronounced decline and recovery of ANC over the period of 1920-1980 in some Sierra Nevada lakes that coincides with the abundance of spheroidal carbonaceous particles (i.e., a diagnostic tracer of fossil fuel combustion) preserved in lake sediments; these patterns appear to be driven by increased emissions of oxidized N and S in the mid-20th Century and reductions in acid precursor levels caused by the Clean Air Act in the 1970s. Thus, when interpreting observational records from western high elevation

[Prediction of potential geographic distribution of Lyme disease in Qinghai province with Maximum Entropy model].

PubMed

Zhang, Lin; Hou, Xuexia; Liu, Huixin; Liu, Wei; Wan, Kanglin; Hao, Qin

2016-01-01

To predict the potential geographic distribution of Lyme disease in Qinghai by using Maximum Entropy model (MaxEnt). The sero-diagnosis data of Lyme disease in 6 counties (Huzhu, Zeku, Tongde, Datong, Qilian and Xunhua) and the environmental and anthropogenic data including altitude, human footprint, normalized difference vegetation index (NDVI) and temperature in Qinghai province since 1990 were collected. By using the data of Huzhu Zeku and Tongde, the prediction of potential distribution of Lyme disease in Qinghai was conducted with MaxEnt. The prediction results were compared with the human sero-prevalence of Lyme disease in Datong, Qilian and Xunhua counties in Qinghai. Three hot spots of Lyme disease were predicted in Qinghai, which were all in the east forest areas. Furthermore, the NDVI showed the most important role in the model prediction, followed by human footprint. Datong, Qilian and Xunhua counties were all in eastern Qinghai. Xunhua was in hot spot areaⅡ, Datong was close to the north of hot spot area Ⅲ, while Qilian with lowest sero-prevalence of Lyme disease was not in the hot spot areas. The data were well modeled in MaxEnt (Area Under Curve=0.980). The actual distribution of Lyme disease in Qinghai was in consistent with the results of the model prediction. MaxEnt could be used in predicting the potential distribution patterns of Lyme disease. The distribution of vegetation and the range and intensity of human activity might be related with Lyme disease distribution.

Analysis on the Change of Vegetation Coverage in Qinghai Province from 2000 TO 2012

NASA Astrophysics Data System (ADS)

Wang, J.; Yan, Q.; Liu, Z.; Luo, C.

2013-07-01

Qinghai Province is one of the important provinces on the Qinghai-Tibet Plateau in China. Its unique alpine meadow ecosystem makes it become the most concentrated areas of biodiversity in high altitudes in the world. Researching the vegetation coverage and changes of Qinghai province can reflect effectively and timely processing of changes and problems of ecological quality in the region. This research will give a long time series monitoring of the vegetation coverage of Qinghai province based on maximum value composite (MVC) and S-G filtering algorithm using MODIS data of the year of 2000-2012, then analyze the change using coefficient of variability(CV) and trend line analysis. According to research, during the past 13 years, more than half of Qinghai Province's vegetation coverage is well, both the east and south have a high coverage, while the northwest is lower. The changing of vegetation coverage also has showed a steady and improving trend in 13 years. The largest area is slight improved area is about 29.08% of the total area, and the second largest area is significant improved area is about 21.09% of the total area. In this research can learn directly the vegetation coverage and changes of Qinghai province and provide reference and scientific basis for the protection and governance of ecological environment.

Minimum size limits for yellow perch (Perca flavescens) in western Lake Erie

USGS Publications Warehouse

Hartman, Wilbur L.; Nepszy, Stephen J.; Scholl, Russell L.

1980-01-01

During the 1960's yellow perch (Perca flavescens) of Lake Erie supported a commercial fishery that produced an average annual catch of 23 million pounds, as well as a modest sport fishery. Since 1969, the resource has seriously deteriorated. Commercial landings amounted to only 6 million pounds in 1976, and included proportionally more immature perch than in the 1960's. Moreover, no strong year classes were produced between 1965 and 1975. An interagency technical committee was appointed in 1975 by the Lake Erie Committee of the Great Lakes Fishery Commission to develop an interim management strategy that would provide for greater protection of perch in western Lake Erie, where declines have been the most severe. The committee first determined the age structure, growth and mortality rates, maturation schedule, and length-fecundity relationship for the population, and then applied Ricker-type equilibrium yield models to determine the effects of various minimum length limits on yield, production, average stock weight, potential egg deposition, and the Abrosov spawning frequency indicator (average number of spawning opportunities per female). The committee recommended increasing the minimum length limit of 5.0 inches to at least 8.5 inches. Theoretically, this change would increase the average stock weight by 36% and potential egg deposition by 44%, without significantly decreasing yield. Abrosov's spawning frequency indicator would rise from the existing 0.6 to about 1.2.

Hydro-meteorological processes on the Qinghai - Tibet Plateau observed from space

NASA Astrophysics Data System (ADS)

Menenti, Massimo; Colin, Jerome; Jia, Li; D'Urso, Guido; Foken, Thomas; Immerzeel, Walter; Jha, Ramakar; Liu, Qinhuo; Liu, Changming; Ma, Yaoming; Sobrino, Jose Antonio; Yan, Guangjian; Pelgrum, Henk; Porcu, Federico; Wang, Jian; Wang, Jiemin; Shen, Xueshun; Su, Zhongbo; Ueno, Kenichi

2014-05-01

The Qinghai - Tibet Plateau is characterized by a significant intra-annual variability and spatial heterogeneity of surface conditions. Snow and vegetation cover, albedo, surface temperature and wetness change very significantly during the year and from place to place. The influence of temporal changes on convective events and the onset of the monsoon has been documented by ground based measurements of land - atmosphere exchanges of heat and water. The state of the land surface over the entire Plateau can be determined by space observation of surface albedo, temperature, snow and vegetation cover and soil moisture. Fully integrated use of satellite and ground observations is necessary to support water resources management in SE Asia and to clarify the roles of the interactions between the land surface and the atmosphere over the Tibetan Plateau in the Asian monsoon system. New or significantly improved algorithms have been developed and evaluated against ground measurements. Variables retrieved include land surface properties, rain rate, aerosol optical depth, water vapour, snow cover and water equivalent, soil moisture and lake level. The three years time series of gap-free daily and hourly evaporation derived from geostationary data collected by the FY-2D satellite was a major achievement. The hydrologic modeling system has been implemented and applied to the Qinghai Tibet Plateau and the headwaters of the major rivers in South and East Asia. Case studies on response of atmospheric circulation and specifically of convective activity to land surface conditions have been completed and the controlling land surface conditions and processes have been documented. Two new drought indicators have been developed: Normalized Temperature Anomaly Index (NTAI) and Normalized Vegetation Anomaly Index (NVAI). Case study in China and India showed that these indicators capture effectively drought severity and evolution. A new method has been developed for monitoring and early

Molecular characterization of Cryptosporidium from animal sources in Qinghai province of China.

PubMed

Karanis, Panagiotis; Plutzer, Judit; Halim, Norhaliza Abdul; Igori, Khatanbaatar; Nagasawa, Hideyuki; Ongerth, Jerry; Liqing, Ma

2007-11-01

The presence of Cryptosporidium oocysts in 20 zoo animals of the Xining Zoo, 16 farm yaks and 42 farm goats in Qinghai province, China was investigated by an immunofluorescence test (IFT). The species and/or genotypes were determined by nested polymerase chain reaction (PCR) and sequence analysis of a fragment of the small subunit (SSU) rRNA gene. Cryptosporidium oocysts were found in 16 zoo animals, 2 yaks, and 15 goats by IFT. The IFT positive samples were further investigated by PCR, and 16 of them were found to be positive by that method also. Sequence analysis of the PCR products derived from Cryptosporidium oocysts from Black leopard (Panthera pardus), Heijing He (Grus nigricollis), Barbary sheep (Ammotragus lervia), Takin (Budorcas taxicolor), Lesser panda (Ailurus fulgens), and White-eared pheasant (Crossoptilon crossoptilon) fecal samples matched that of Cryptosporidium parvum mouse genotype. Sequence analyses of other PCR products were consistent with cervine genotype Cryptosporidium from Ibex (Capra ibex), a novel Cryptosporidium genotype from a wild yak (Bos mutus), C. bovis-like genotype from one goat sample and also a novel Cryptosporidium genotype from one other separate goat sample. The present work reports the first data on Cryptosporidium infections in animals from the Qinghai province of mountainous central western China and the first findings of the 'cervine' genotype in Capra ibex, C. bovis-like genotype and the new Cryptosporidium spp. in farm goat and in wild yak.

Pleistocene lake level changes in Western Mongolia

NASA Astrophysics Data System (ADS)

Borodavko, P. S.

2009-04-01

Global cooling in the Early Pleistocene caused extensive continental glaciation in the northern hemisphere including the arid areas of Central Asia. The reduction of temperatures (particularly summer temperatures) reduced evaporation and strengthened the importance of precipitation. The simultaneity of "lakes periods" (pluvials) and stages of glaciation is established experience confirmed by investigations in the west of North America and Russia. In the Mongolian Great Lakes Depression new evidence for similar conditions is found. The Great Lakes Depression is one of the largest in Central Asia, and is divided into 2 main Lakes basins: Hyargas Lake Basin and Uvs Lake Basin. The basin is 600-650 km in length with a width of 200-250 km in the north and 60-100 km in the south. Total catchment area is about 186600 km2. The elevation of the basin floor is from 1700 m a.s.l. to 760 m a.s.l., decreasing to the north and south-east. The depression extends south-north and is bounded by mountains: Tannu-Ola to the north, Hangai to the east; Gobi Altai to the south and Mongolian Altay to the west. The maximum elevation of the mountains is 4000 m a.s.l. There are some mountains with an elevation between 2000 and 3000 m a.s.l in the lake catchment. These mountains are not glaciated today. The geological record [1] suggests the Great Lakes Depression already existed in the Mesozoic, but assumed its modern form only during the Pliocene-Quaternary when tectonic movements caused the uplift of the surrounding mountains. A phase of tectonic stability occurred during the Late Quaternary. The depression is filled by Quaternary fluvial, aeolian and lacustrine deposits (e.g. sand, pebbles). The Neogene deposits are represented by coloured clay, marl, sand and sandstone [1]. Hyargas Lake is the end base level of erosion of the lake group consisting of the Hara-Us Nur, Dorgon, Hara Nur and Airag lakes. Hyargas is one of the largest lakes in Mongolia, with a water surface of 1,407 km2. The

Turbidity in extreme western Lake Superior. [contamination of Duluth, Minnesota water intake

NASA Technical Reports Server (NTRS)

Sydor, M.

1975-01-01

Data were obtained from ERTS images for western Lake Superior for 1972-74. Data examination showed that for easterly winds the turbidity originating along the Wisconsin shore and the resuspension areas are transported northward then out along a N.E. path where it disperses, and often, for large storms, contaminates the Duluth water intake. Contaminants such as dredging fines anywhere along these paths would likewise find their way to the intake areas in concentrations comparable to the relative red clay concentration.

Mosquitoes and Mosquito-Borne Arboviruses in the Qinghai-Tibet Plateau—Focused on the Qinghai Area, China

PubMed Central

Li, Wen-Juan; Wang, Jing-Lin; Li, Ming-Hua; Fu, Shi-Hong; Wang, Huan-Yu; Wang, Zhi-Yu; Jiang, Shuang-Ying; Wang, Xue-Wen; Guo, Peng; Zhao, Sheng-Cang; Shi, Yan; Lu, Nan-Nan; Nasci, Roger S.; Tang, Qing; Liang, Guo-Dong

2010-01-01

An investigation was conducted to identify the distribution of mosquitoes and mosquito-borne arboviruses in the Qinghai-Tibet Plateau, China from July to August in 2007. A total of 8,147 mosquitoes representing six species from three genera (Aedes, Culex, and Anopheles) were collected in three locations (Geermu city, altitude of 2,780 m; Xining city, 2,200 m; Minhe county, 1,700 m). Six virus isolates were obtained including Tahyna virus (TAHV), Liaoning virus, and Culex pipiens pallens Densovirus. A serosurvey showed immunoglobulin G antibodies by immunofluorescence assay (IFA) against TAHV in residents of all three locations. The IFA-positive human samples were confirmed by 90% plaque-reduction neutralization tests (PRNT90) against TAHV with titers ranging from 1:20 to 1:10,240. In addition, TAHV seropositive cows, sheep, and swine were found in these locations. This investigation represents the first isolation of TAHV from Ae. (Och.) detritus and the first evidence of TAHV infection in residents and livestock in the Qinghai-Tibet Plateau. PMID:20348523

amoA-encoding archaea and thaumarchaeol in the lakes on the northeastern Qinghai-Tibetan Plateau, China

PubMed Central

Yang, Jian; Jiang, Hongchen; Dong, Hailiang; Wang, Huanye; Wu, Geng; Hou, Weiguo; Liu, Weiguo; Zhang, Chuanlun; Sun, Yongjuan; Lai, Zhongping

2013-01-01

All known ammonia-oxidizing archaea (AOA) belong to the phylum Thaumarchaeota within the domain Archaea. AOA possess the diagnostic amoA gene (encoding the alpha subunit of ammonia monooxygenase) and produce lipid biomarker thaumarchaeol. Although the abundance and diversity of amoA gene-encoding archaea (AEA) in freshwater lakes have been well-studied, little is known about AEA ecology in saline/hypersaline lakes. In this study, the distribution of the archaeal amoA gene and thaumarchaeol were investigated in nine Qinghai–Tibetan lakes with a salinity range from freshwater to salt-saturation (salinity: 325 g L-1). The results showed that the archaeal amoA gene was present in hypersaline lakes with salinity up to 160 g L-1. The archaeal amoA gene diversity in Tibetan lakes was different from those in other lakes worldwide, suggesting Tibetan lakes (high elevation, strong ultraviolet, and dry climate) may host a unique AEA population of different evolutionary origin from those in other lakes. Thaumarchaeol was present in all of the studied hypersaline lakes, even in those where no AEA amoA gene was observed. Future research is needed to determine the ecological function of AEA and possible sources of thaumarchaeol in the Qinghai–Tibetan hypersaline lakes. PMID:24273535

Diets of emerald and spottail shiners and potential interactions with other western Lake Erie planktivorous fishes

USGS Publications Warehouse

Hartman, Kyle J.; Vondracek, Bruce; Parrish, Donna L.; Muth, Kenneth M.

1992-01-01

Emerald shiner (Notropis atherinoides) and spottail shiner (N. hudsonius) were abundant historically in western Lake Erie. Recent changes in the fish community suggest that shiners may not compete favorably with the invading white perch (Morone americana) or the gizzard shad (Dorosoma cepedianum). We examined the diets of emerald and spottail shiner and compared them to other planktivores in western Lake Erie. Emerald and spottail shiner ate cladocerans such as Daphnia spp.,Leptodora, and Bythotrephes. Biologically significant overlaps (Schoener 1970 index ≥ 0.6) among zooplanktivores occurred from July through September, but most occurred during July. The frequency of significant diet overlaps among planktivores declined since an earlier study in the mid-1970s (Muth and Busch 1989) possibly indicating that competitive interactions have eased since 1975. In addition to competitive interactions, other factors such as increased eutrophication and predator mediated mortality likely played a role in planktivore community changes since the early 1970s.

National Surface Water Survey, western wilderness area lakes: environmental assessment. Draft

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-03-01

The US Environmental Protection Agency (EPA) is proposing to sample 498 lakes in federally designated wilderness areas and national parks during the western part of the National Surface Water Survey (NSW). The NSWS has been undertaken to provide high quality data for evaluating the nature and extent of acid deposition throughout the United States. Sampling protocols established for the national survey call for the use of helicopters to gain access to lakes for sampling. Helicopters have already been used in the eastern and midwestern parts of the survey. The US Forest Service (FS) and the National Park Service (NPS) willmore » have to decide which sampling plan for wilderness areas, if any, can be approved under the Wilderness Act of 1964. This Environmental Assessment (EA) has been prepared to evaluate the environmental consequences of alternative means of gaining access to wilderness areas to meet the objectives of the NSWS. Based on this evaluation, EPA has reviewed the possible sampling alternatives and reached a conclusion on the preferred alternative. This assessment is being provided to the FS and the NPS for their use in evaluating the alternatives, including EPA's preferred one. As a result of its evaluation, EPA believes that wilderness area lakes should be included in the survey and that the preferred means of access is using helicopters. 94 references, 14 figures, 18 tables.« less

Early emergence of anthropogenically forced heat waves in the western United States and Great Lakes

NASA Astrophysics Data System (ADS)

Lopez, Hosmay; West, Robert; Dong, Shenfu; Goni, Gustavo; Kirtman, Ben; Lee, Sang-Ki; Atlas, Robert

2018-05-01

Climate projections for the twenty-first century suggest an increase in the occurrence of heat waves. However, the time at which externally forced signals of anthropogenic climate change (ACC) emerge against background natural variability (time of emergence (ToE)) has been challenging to quantify, which makes future heat-wave projections uncertain. Here we combine observations and model simulations under present and future forcing to assess how internal variability and ACC modulate US heat waves. We show that ACC dominates heat-wave occurrence over the western United States and Great Lakes regions, with ToE that occurred as early as the 2020s and 2030s, respectively. In contrast, internal variability governs heat waves in the northern and southern Great Plains, where ToE occurs in the 2050s and 2070s; this later ToE is believed to be a result of a projected increase in circulation variability, namely the Great Plain low-level jet. Thus, greater mitigation and adaptation efforts are needed in the Great Lakes and western United States regions.

Contrasting responses to Pleistocene climate changes: a case study of two sister species Allium cyathophorum and A. spicata (Amaryllidaceae) distributed in the eastern and western Qinghai-Tibet Plateau.

PubMed

Wang, Xinyu; Li, Yuanshuo; Liang, Qianlong; Zhang, Lei; Wang, Qian; Hu, Huan; Sun, Yongshuai

2015-04-01

It has been hypothesized that species occurring in the eastern and the western Qinghai-Tibet Plateau (QTP) responded differently to climate changes during the Pleistocene. Here, we test this hypothesis by phylogeographic analysis of two sister species, Allium cyathophorum and A. spicata. We sequenced two chloroplast DNA (cpDNA) fragments (accD-psaI and the rpl16 intron) of 150 individuals, and the nuclear (ITS) region of 114 individuals, from 19 populations throughout the distributional ranges of these species. The divergence between the two species was dated at 779 - 714 thousand years before the present and was likely initiated by the most major glaciation in the QTP. Analysis of chlorotype diversity showed that A. spicata, the species occurring in the western QTP, contains much lower genetic diversity (0.25) than A. cyathophorum (0.93), which is distributed in the eastern QTP. Moreover, multiple independent tests suggested that the A. spicata population had expanded recently, while no such expansion was detected in A. cyathophorum, indicating a contrasting pattern of responses to Pleistocene climate changes. These findings highlight the importance of geographical topography in determining how species responded to the climate changes that took place in the QTP during the Pleistocene.

A reconnaissance study of oxygen, hydrogen and strontium isotopes in geochemically diverse lakes, Western Nebraska, USA

USGS Publications Warehouse

Gosselin, D.C.; Nabelek, P.E.; Peterman, Z.E.; Sibray, S.

1997-01-01

Reconnaissance ??18O,, ??D, and ??87Sr data for fifteen lakes in the Western Lakes Region of the Sand Hills of Nebraska indicate dynamic hydrologic systems. The rather narrow range of ??87Sr from lake water (1.1 to 2.1) and groundwater (0.9 to 1.7) indicates that the groundwater is generally unradiogenic. Groundwater residence times and relatively unradiogenic volcanic ash within the dune sediments control the ??87Sr values. Based on the mutual variations of ??18O and ??D, the lakes can be divided into three groups. In Group 1, both ??18O and ??D values increase from spring to fall. The ??18O and ??D values in Group 2 decreased from spring to fall. Group 3 are ephemeral lakes that went dry some time during 1992. The data and isotopic modeling show that variations in the ratio of evaporation relative to groundwater inflow, local humidity conditions, and the ??(a) has substantial influence on the isotopic composition. In addition, isotopic behavior in ephemeral hakes can be rather unusual because of the changing activities of water and mineral precipitation and redissolution. The annual and interannual isotopic variability of these lakes which is reflected in the paleonvironmental indicators may be the rule rather than the exception in these types of systems.

Western Lake Erie Basin: Soft-data-constrained, NHDPlus resolution watershed modeling and exploration of applicable conservation scenarios

USDA-ARS?s Scientific Manuscript database

Complex watershed simulation models are powerful tools that can help scientists and policy-makers address challenging topics, such as land use management and water security. In the Western Lake Erie Basin (WLEB), complex hydrological models have been applied at various scales to help describe relat...

Elemental carbon and polycyclic aromatic compounds in a 150-year sediment core from Lake Qinghai, Tibetan Plateau, China: influence of regional and local sources and transport pathways.

PubMed

Han, Y M; Wei, C; Bandowe, B A M; Wilcke, W; Cao, J J; Xu, B Q; Gao, S P; Tie, X X; Li, G H; Jin, Z D; An, Z S

2015-04-07

Elemental carbon (EC) and polycyclic aromatic compounds (PACs) are potential proxies for the reconstruction of change in human activities and the origin of air masses in historic times. In this study, the historic deposition of char and soot (the two subtypes of EC) and PACs in a 150-year sediment core from different topographic subbasins of Lake Qinghai on the Qinghai Tibetan Plateau (QTP) were reconstructed. The objective was to explore how the variations in the concentrations of EC and PACs, in the ratios of char to soot and of oxygenated polycyclic aromatic hydrocarbons (OPAHs) to parent PAHs, and in the composition of the PAC mixtures reflect historical changes in climate and human activity and the origin of air masses arriving at the QTP. The deposition fluxes of soot in the different subbasins were similar, averaging 0.18 (range of 0.15-0.25) and 0.16 (0.13-0.23) g m(-2) year(-1), respectively, but they varied for char (averaging 0.11 and 0.22 g m(-2) year(-1), respectively), suggesting ubiquitous atmospheric deposition of soot and local river inputs of char. The different vertical distributions of the char/soot ratios in the different subbasins can be interpreted in terms of the different transport mechanisms of char and soot. An abrupt increase in soot concentrations since 1980 coincides with results from the QTP ice cores that were interpreted to be indicative of soot transport from South Asia. Similar concentration patterns of PAHs with soot and 9,10-anthraquinone/anthracene (9,10-AQ/ANT) ratios all >2.0 suggest regional PAC sources. Increasing PAH/soot ratios and decreasing 9,10-AQ/ANT ratios since the beginning of the 1970s indicate increasing local emissions. The historical trends of these diagnostic ratios indicate an increase in the fossil-fuel contribution since the beginning of the 1970s. The increase of perylene concentrations with increasing core depth and the ratio of perylene to its penta-aromatic isomers indicate that perylene originates

Late Holocene lake-level fluctuations in Walker Lake, Nevada, USA

USGS Publications Warehouse

Yuan, F.; Linsley, B.K.; Howe, S.S.; Lund, S.P.; McGeehin, J.P.

2006-01-01

Walker Lake, a hydrologically closed, saline, and alkaline lake, is situated along the western margin of the Great Basin in Nevada of the western United States. Analyses of the magnetic susceptibility (??), total inorganic carbon (TIC), and oxygen isotopic composition (??18O) of carbonate sediments including ostracode shells (Limnocythere ceriotuberosa) from Walker Lake allow us to extend the sediment record of lake-level fluctuations back to 2700??years B.P. There are approximately five major stages over the course of the late Holocene hydrologic evolution in Walker Lake: an early lowstand (> 2400??years B.P.), a lake-filling period (??? 2400 to ??? 1000??years B.P.), a lake-level lowering period during the Medieval Warm Period (MWP) (??? 1000 to ??? 600??years B.P.), a relatively wet period (??? 600 to ??? 100??years B.P.), and the anthropogenically induced lake-level lowering period (< 100??years B.P.). The most pronounced lowstand of Walker Lake occurred at ??? 2400??years B.P., as indicated by the relatively high values of ??18O. This is generally in agreement with the previous lower resolution paleoclimate results from Walker Lake, but contrasts with the sediment records from adjacent Pyramid Lake and Siesta Lake. The pronounced lowstand suggests that the Walker River that fills Walker Lake may have partially diverted into the Carson Sink through the Adrian paleochannel between 2700 to 1400??years B.P. ?? 2006 Elsevier B.V. All rights reserved.

Genetic variation and phylogenetic relationships of the ectomycorrhizal Floccularia luteovirens on the Qinghai-Tibet Plateau.

PubMed

Xing, Rui; Gao, Qing-Bo; Zhang, Fa-Qi; Fu, Peng-Cheng; Wang, Jiu-Li; Yan, Hui-Ying; Chen, Shi-Long

2017-08-01

Floccularia luteovirens, as an ectomycorrhizal fungus, is widely distributed in the Qinghai-Tibet Plateau. As an edible fungus, it is famous for its unique flavor. Former studies mainly focus on the chemical composition and genetic structure of this species. However, the phylogenetic relationship between genotypes remains unknown. In this study, the genetic variation and phylogenetic relationship between the genotypes of F. luteovirens in Qinghai-Tibet Plateau was estimated through the analysis on two protein-coding genes (rpb1 and ef-1α) from 398 individuals collected from 24 wild populations. The sample covered the entire range of this species during all the growth seasons from 2011 to 2015. 13 genotypes were detected and moderate genetic diversity was revealed. Based on the results of network analysis, the maximum likelihood (ML), maximum parsimony (MP), and Bayesian inference (BI) analyses, the genotypes H-1, H-4, H-6, H-8, H-10, and H-11 were grouped into one clade. Additionally, a relatively higher genotype diversity (average h value is 0.722) and unique genotypes in the northeast edge of Qinghai- Tibet plateau have been found, combined with the results of mismatch analysis and neutrality tests indicated that Southeast Qinghai-Tibet plateau was a refuge for F. luteovirens during the historical geological or climatic events (uplifting of the Qinghai-Tibet Plateau or Last Glacial Maximum). Furthermore, the present distribution of the species on the Qinghai-Tibet plateau has resulted from the recent population expansion. Our findings provide a foundation for the future study of the evolutionary history and the speciation of this species.

Inorganic pollution around the Qinghai-Tibet Plateau: An overview of the current observations.

PubMed

Wu, Jun; Duan, Dongping; Lu, Jian; Luo, Yongming; Wen, Xiaohu; Guo, Xiaoying; Boman, Brian J

2016-04-15

The Qinghai-Tibet Plateau is the highest geographical unit in the world. Thus, it serves an important role in evaluating long-term ecologic conditions and environmental status and changes over time. This study summarizes major and trace element concentrations in biota and in water and soil. It also pays attention to gaseous pollutant and particle concentrations in air around the Qinghai-Tibet Plateau. The degree of soil heavy metal contamination and the water heavy metal hazard index were respectively evaluated. The contamination degrees of two sampling areas around the Qinghai-Tibet Plateau reached extremely high levels with soil mCd (modified degree of contamination) values exceeding 20. Surprisingly, over 54% of sampling areas showed moderate or more serious soil contamination degree (mCd>1.5). Moreover, the hazard indexes of two important rivers were 1.56 and 7.59, reaching unacceptable level. The potential risk might be beyond our expectation. Therefore, it should be an urgent and top priority to identify and confirm possible pollution sources around the Qinghai-Tibet Plateau. Then, it is imperative to implement feasible and effective environmental quality control strategies. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantitative precipitation estimates for the northeastern Qinghai-Tibetan Plateau over the last 18,000 years

NASA Astrophysics Data System (ADS)

Li, Jianyong; Dodson, John; Yan, Hong; Cheng, Bo; Zhang, Xiaojian; Xu, Qinghai; Ni, Jian; Lu, Fengyan

2017-05-01

Quantitative information regarding the long-term variability of precipitation and vegetation during the period covering both the Late Glacial and the Holocene on the Qinghai-Tibetan Plateau (QTP) is scarce. Herein, we provide new and numerical reconstructions for annual mean precipitation (PANN) and vegetation history over the last 18,000 years using high-resolution pollen data from Lakes Dalianhai and Qinghai on the northeastern QTP. Hitherto, five calibration techniques including weighted averaging, weighted average-partial least squares regression, modern analogue technique, locally weighted weighted averaging regression, and maximum likelihood were first employed to construct robust inference models and to produce reliable PANN estimates on the QTP. The biomization method was applied for reconstructing the vegetation dynamics. The study area was dominated by steppe and characterized with a highly variable, relatively dry climate at 18,000-11,000 cal years B.P. PANN increased since the early Holocene, obtained a maximum at 8000-3000 cal years B.P. with coniferous-temperate mixed forest as the dominant biome, and thereafter declined to present. The PANN reconstructions are broadly consistent with other proxy-based paleoclimatic records from the northeastern QTP and the northern region of monsoonal China. The possible mechanisms behind the precipitation changes may be tentatively attributed to the internal feedback processes of higher latitude (e.g., North Atlantic) and lower latitude (e.g., subtropical monsoon) competing climatic regimes, which are primarily modulated by solar energy output as the external driving force. These findings may provide important insights into understanding the future Asian precipitation dynamics under the projected global warming.

Golden Key Program. Common Education for Visually Impaired Children in Western China.

ERIC Educational Resources Information Center

Xu, Bailun

This paper describes a new program in the Western provinces of China (Guangxi, Guizhou, Yunnan, Gansu, Ningxia, Qinghai, Xinjiang, Tibet, and Inner Mongolia) that is designed to integrate 20,000 children with low-vision into general education classrooms. The Golden Key Research Center of Education for Visually Impaired has been working with the…

[The pathogenic ecology research on plague in Qinghai plateau].

PubMed

Dai, Rui-xia; Wei, Bai-qing; Li, Cun-xiang; Xiong, Hao-ming; Yang, Xiao-yan; Fan, Wei; Qi, Mei-ying; Jin, Juan; Wei, Rong-jie; Feng, Jian-ping; Jin, Xing; Wang, Zu-yun

2013-12-01

To study the pathogenic ecology characteristics of plague in Qinghai plateau. Applied molecular biology techniques, conventional technologies and geographic information system (GIS) to study phenotypic traits, plasmid spectrum, genotype, infected host and media spectrum etc.of 952 Yersinia pestis strains in Qinghai plateau plague foci, which were separated from different host and media in different regions during 1954 to 2012. The ecotypes of these strains were Qingzang plateau (91.49%, 871/952),Qilian mountain (6.41%, 61/952) and Microtus fuscus (1.26%, 12/952).83.6% (796/952) of these strains contained all the 4 virulence factors (Fr1, Pesticin1,Virulence antigen, and Pigmentation), 93.26% (367/392) were velogenic strains confirmed by virulence test.725 Yersinia pestis strains were separated from Qinghai plateau plague foci carried 9 kinds of plasmid, among which 713 strains from Marmot himalayan plague foci carried 9 kinds of plasmid, the Mr were 6×10(6), 7×10(6), 23×10(6), 27×10(6), 30×10(6), 45×10(6), 52×10(6), 65×10(6) and 92×10(6) respectively. 12 Yersinia pestis strains were separated from Microtus fuscus plague foci carried only 3 kinds of plasmid, the Mr were 6×10(6), 45×10(6), 65×10(6). Meanwhile, the strains carrying large plasmid (52×10(6), 65×10(6) and 92×10(6)) were only distributed in particular geographical location, which had the category property. The research also confirmed that 841 Yersinia pestis strains from two kinds of plague foci in Qinghai plateau had 11 genomovars. The strains of Marmot himalayan plague foci were given priority to genomovar 5 and 8, amounted to 611 strains, genomovar 8 accounted for 56.00% (471/841), genomovar 5 accounted for 23.07% (194/841). Besides, 3 new genomovars, including new 1(62 strains), new 2(52 strains), new 3(48 strains) were newly founded, and 12 strains of Microtus fuscus plague foci were genomovar 14. The main host and media of Qinghai plateau plague foci directly affected the spatial

Development of a Zooplankton Assemblage Indicator for the 2012 National Lakes Assessment: Performance in the Western U.S.

EPA Science Inventory

We used zooplankton count data collected as part of the 2012 National Lakes Assessment (NLA) to develop candidate metrics and multimetric indices (MMIs) for five aggregated ecoregions of the conterminous USA (Coastal Plains, Eastern Highlands, Plains, Upper Midwest, and Western M...

A late quaternary record of eolian silt deposition in a maar lake, St. Michael Island, western Alaska

USGS Publications Warehouse

Muhs, D.R.; Ager, T.A.; Been, J.; Bradbury, J.P.; Dean, W.E.

2003-01-01

Recent stratigraphic studies in central Alaska have yielded the unexpected finding that there is little evidence for full-glacial (late Wisconsin) loess deposition. Because the loess record of western Alaska is poorly exposed and not well known, we analyzed a core from Zagoskin Lake, a maar lake on St. Michael Island, to determine if a full-glacial eolian record could be found in that region. Particle size and geochemical data indicate that the mineral fraction of the lake sediments is not derived from the local basalt and is probably eolian. Silt deposition took place from at least the latter part of the mid-Wisconsin interstadial period through the Holocene, based on radiocarbon dating. Based on the locations of likely loess sources, eolian silt in western Alaska was probably deflated by northeasterly winds from glaciofluvial sediments. If last-glacial winds that deposited loess were indeed from the northeast, this reconstruction is in conflict with a model-derived reconstruction of paleowinds in Alaska. Mass accumulation rates in Zagoskin Lake were higher during the Pleistocene than during the Holocene. In addition, more eolian sediment is recorded in the lake sediments than as loess on the adjacent landscape. The thinner loess record on land may be due to the sparse, herb tundra vegetation that dominated the landscape in full-glacial time. Herb tundra would have been an inefficient loess trap compared to forest or even shrub tundra due to its low roughness height. The lack of abundant, full-glacial, eolian silt deposition in the loess stratigraphic record of central Alaska may be due, therefore, to a mimimal ability of the landscape to trap loess, rather than a lack of available eolian sediment. ?? 2003 University of Washington. Published by Elsevier Inc. All rights reserved.

Spatial variation in biofouling of a unionid mussel (Lampsilis siliquoidea) across the western basin of Lake Erie

USGS Publications Warehouse

Larson, James H.; Evans, Mary; Richardson, William B.; Schaeffer, Jeff; Nelson, John

2016-01-01

Invasion of North American waters by nonnative Dreissena polymorpha and D. rostriformis bugensishas resulted in declines of the Unionidae family of native North American mussels. Dreissenid mussels biofoul unionid mussels in large numbers and interfere with unionid movement, their acquisition of food, and the native mussels' ability to open and close their shells. Initial expectations for the Great Lakes included extirpation of unionids where they co-occurred with dreissenids, but recently adult and juvenile unionids have been found alive in several apparent refugia. These unionid populations may persist due to reduced dreissenid biofouling in these areas, and/or due to processes that remove biofoulers. For example locations inaccessible to dreissenid veligers may reduce biofouling and habitats with soft substrates may allow unionids to burrow and thus remove dreissenids. We deployed caged unionid mussels (Lampsilis siliquoidea) at 36 sites across the western basin of Lake Erie to assess spatial variation in biofouling and to identify other areas that might promote the persistence or recovery of native unionid mussels. Biofouling ranged from 0.03 – 26.33 g per mussel, reached a maximum in the immediate vicinity of the mouth of the Maumee River, and appeared to primarily consist of dreissenid mussels. A known mussel refugium in the vicinity of a power plant near the mouth of the Maumee actually exhibited very high biofouling rates, suggesting that low dreissenid colonization did not adequately explain unionid survival in this refugium. In contrast, the southern nearshore area of Lake Erie, near another refugium, had very low biofouling. A large stretch of the western basin appeared to have low biofouling rates and muddy substrates, raising the possibility that these open water areas could support remnant and returning populations of unionid mussels. Previous observations of unionid refugia and the occurrence of low biofouling rates in large areas of the western

Changes in the dreissenid community in the lower Great Lakes with emphasis on southern Lake Ontario

USGS Publications Warehouse

Mills, Edward L.; Chrisman, Jana R.; Baldwin, Brad; Owens, Randall W.; O'Gorman, Robert; Howell, Todd; Roseman, Edward F.; Raths, Melinda K.

1999-01-01

A field study was conducted in the lower Great Lakes to assess changes in spatial distribution and population structure of dreissenid mussel populations. More specifically, the westward range expansion of quagga mussel into western Lake Erie and toward Lake Huron was investigated and the shell size, density, and biomass of zebra and quagga mussel with depth in southern Lake Ontario in 1992 and 1995 were compared. In Lake Erie, quagga mussel dominated the dreissenid community in the eastern basin and zebra mussel dominated in the western basin. In southern Lake Ontario, an east to west gradient was observed with the quagga mussel dominant at western sites and zebra mussel dominant at eastern locations. Mean shell size of quagga mussel was generally larger than that of zebra mussel except in western Lake Erie and one site in eastern Lake Erie. Although mean shell size and our index of numbers and biomass of both dreissenid species increased sharply in southern Lake Ontario between 1992 and 1995, the increase in density and biomass was much greater for quagga mussels over the 3-year period. In 1995, zebra mussels were most abundant at 15 to 25 m whereas the highest numbers and biomass of quagga mussel were at 35 to 45 m. The quagga mussel is now the most abundant dreissenid in areas of southern Lake Ontario where the zebra mussel was once the most abundant dreissenid; this trend parallels that observed for dreissenid populations in the Dneiper River basin in the Ukraine.

Unraveling of permafrost hydrological variabilities on Central Qinghai-Tibet Plateau using stable isotopic technique.

PubMed

Yang, Yuzhong; Wu, Qingbai; Hou, Yandong; Zhang, Zhongqiong; Zhan, Jing; Gao, Siru; Jin, Huijun

2017-12-15

Permafrost degradation on the Qinghai-Tibet Plateau (QTP) will substantially alter the surface runoff discharge and generation, which changes the recharge processes and influences the hydrological cycle on the QTP. Hydrological connections between different water bodies and the influence of thawing permafrost (ground ice) are not well understood on the QTP. This study applied water stable isotopic method to investigate the permafrost hydrological variabilities in Beiluhe Basin (BLB) on Central QTP. Isotopic variations of precipitation, river flow, thermokarst lake, and near-surface ground ice were identified to figure out the moisture source of them, and to elaborate the hydrological connections in permafrost region. Results suggested that isotopic seasonalities in precipitation is evident, it is showing more positive values in summer seasons, and negative values in winter seasons. Stable isotopes of river flow are mainly distributed in the range of precipitation which is indicative of important replenishment from precipitation. δ 18 O, δD of thermokarst lakes are more positive than precipitation, indicating of basin-scale evaporation of lake water. Comparison of δ I values in different water bodies shows that hydrology of thermokarst lakes was related to thawing of permafrost (ground ice) and precipitation. Near-surface ground ice in BLB exhibits different isotopic characteristics, and generates a special δD-δ 18 O relationship (freezing line): δD=5.81δ 18 O-23.02, which reflects typical freezing of liquid water. From isotopic analysis, it is inferred that near-surface ground ice was mainly recharged by precipitation and active layer water. Stable isotopic and conceptual model is suggestive of striking hydrological connections between precipitation, river flow, thermokarst lake, and ground ice under degrading permafrost. This research provides fundamental comprehensions into the hydrological processes in permafrost regions on QTP, which should be considered

Surveillance of Echinococcus isolates from Qinghai, China.

PubMed

Ma, Junying; Wang, Hu; Lin, Gonghua; Zhao, Fang; Li, Chao; Zhang, Tongzuo; Ma, Xiao; Zhang, Yongguo; Hou, Zhibin; Cai, Huixia; Liu, Peiyun; Wang, Yongshun

2015-01-15

Echinococcosis is highly endemic over large parts of the Qinghai-Tibet Plateau (QTP), China. Based on a large number of samples, we present data on the current presence, host distribution, and genetic diversity of Echinococcus in the Qinghai Province, located in the northeastern corner of the QTP and constituting >25% of the area of the plateau. We used 521 samples (including 451 newly collected samples and 70 samples from our previous study) from humans, yaks, sheep, goats, dogs, fox, plateau pikas, and voles in 36 counties, and genotyped them using the mitochondrial DNA marker cytochrome oxidase subunit I (cox1) gene and the maximum parsimony and Bayesian reconstruction methods. Based on the 792 bp sequence matrix, we recorded 177 variable sites; 157 were parsimony-informative. A total of 105 haplotypes (H1-H105) were detected, of which H1-H15 and H90-H104, H16-H17, H18-H89, and H105 belonged to Echinococcus shiquicus, Echinococcus multilocularis, Echinococcus granulosus, and Echinococcus canadensis, respectively. Our results showed that, (i) the Qinghai Province was under a high burden of Echinococcus epidemiology; (ii) E. granulosus was the main echinococcosis threat to the local people, and the followed is E. multilocularis; (iii) there are a considerable number of haplotypes shared by domestic animals (sheep, yaks, and dogs) and humans, demonstrating the close relationship between human and domestic animals epidemiology; (iv) the threat of E. shiquicus on humans and livestock can be mostly ignored, while the infection risk of E. canadensis echinococcosis should not be neglected. Copyright © 2014 Elsevier B.V. All rights reserved.

National Water-Quality Assessment Program - Western Lake Michigan Drainage Basin

USGS Publications Warehouse

Setmire, J.O.

1991-01-01

A major component of the program is study-unit investigations, which comprise the princ ipal bui lding blocks of the program on which national-level asses ment activities a re based . The 60 study-unit in vestigations that make up the program are hydrologic systems that include parts of most major river bas ins and a qui fer systems. These study units cover areas of I ,200 to more than 65 ,000 square mi les and incorporate about 60 to 70 percent of the Nation's water use and popul ation e rved by public water supply. In 1991 , the Western Lake Michigan drainage basin was among the fir st 20 NA WQA study unit selected for study under the full -scale implementation plan.

REGIONAL, WATERSHED, AND SITE-SPECIFIC ENVIRONMENTAL INFLUENCES ON FISH ASSEMBLAGE STRUCTURE AND FUNCTION IN WESTERN LAKE SUPERIOR TRIBUTARIES

EPA Science Inventory

The relative importance of regional, watershed, and in-stream environmental factors on stream fish assemblage structure and function was investigated as part of a comparative watershed project in the western Lake Superior basin. We selected 48 second and third order watersheds fr...

Investigations into early rift development and geothermal resources in the Pyramid Lake fault zone, Western Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisses, A.; Kell, A.; Kent, G.

A. K. Eisses, A. M. Kell, G. Kent, N. W. Driscoll, R. E. Karlin, R. L. Baskin, J. N. Louie, S. Pullammanappallil, 2010, Investigations into early rift development and geothermal resources in the Pyramid Lake fault zone, Western Nevada: Abstract T33C-2278 presented at 2010 Fall Meeting, AGU, San Francisco, Calif., 13-17 Dec.

Water quality in the Western Lake Michigan Drainages, Wisconsin and Michigan, 1992-95

USGS Publications Warehouse

Peters, Charles A.; Robertson, Dale M.; Saad, David A.; Sullivan, Daniel J.; Scudder, Barbara C.; Fitzpatrick, Faith A.; Richards, Kevin D.; Stewart, Jana S.; Fitzgerald, Sharon A.; Lenz, Bernard N.

1998-01-01

This report is intended to summarize major findings that emerged between 1992 and 1995 from the water-quality assessment of the Western Lake Michigan Drainages Study Unit and torelate these findings to water-quality issues of regional and national concern. The information in primarily intended for those who are involved in water-resource management. Yet, the information contained here may also interest those who simply wish to know more about the quality of water in the rivers and aquifers in the area where they live.

Nahcolite and halite deposition through time during the saline mineral phase of Eocene Lake Uinta, Piceance Basin, western Colorado

USGS Publications Warehouse

Johnson, Ronald C.; Brownfield, Michael E.

2013-01-01

Halite and the sodium bicarbonate mineral nahcolite were deposited during the saline phase of Eocene Lake Uinta in the Piceance Basin, western Colorado. Variations in the area of saline mineral deposition through time were interpreted from studies of core and outcrop. Saline minerals were extensively leached by groundwater, so the original extent of saline deposition was estimated from the distribution of empty vugs and collapse breccias. Vugs and breccias strongly influence groundwater movement, so determining where leaching has occurred is an important consideration for in-situ oil shale extraction methods currently being developed. Lake Uinta formed when two smaller fresh water lakes, one in the Uinta Basin of eastern Utah and the other in the Piceance Basin of western Colorado, expanded and coalesced across the Douglas Creek arch, an area of comparatively low subsidence rates. Salinity increased shortly after this expansion, but saline mineral deposition did not begin until later, after a period of prolonged infilling created broad lake-margin shelves and a comparatively small deep central lake area. These shelves probably played a critical role in brine evolution. A progression from disseminated nahcolite and nahcolite aggregates to bedded nahcolite and ultimately to bedded nahcolite and halite was deposited in this deep lake area during the early stages of saline deposition along with rich oil shale that commonly shows signs of slumping and lateral transport. The area of saline mineral and rich oil shale deposition subsequently expanded, in part due to infilling of the compact deep area, and in part because of an increase in water flow into Lake Uinta, possibly due to outflow from Lake Gosiute to the north. Finally, as Lake Uinta in the Piceance Basin was progressively filled from north to south by volcano-clastic sediment, the saline depocenter was pushed progressively southward, eventually covering much of the areas that had previously been marginal shelves

Genetic diversity and distribution patterns of host insects of Caterpillar Fungus Ophiocordyceps sinensis in the Qinghai-Tibet Plateau.

PubMed

Quan, Qing-Mei; Chen, Ling-Ling; Wang, Xi; Li, Shan; Yang, Xiao-Ling; Zhu, Yun-Guo; Wang, Mu; Cheng, Zhou

2014-01-01

The caterpillar fungus Ophiocordyceps sinensis is one of the most valuable medicinal fungi in the world, and it requires host insects in family Hepialidae (Lepidoptera) to complete its life cycle. However, the genetic diversity and phylogeographic structures of the host insects remain to be explored. We analyzed the genetic diversity and temporal and spatial distribution patterns of genetic variation of the host insects throughout the O. sinensis distribution. Abundant haplotype and nucleotide diversity mainly existed in the areas of Nyingchi, ShangriLa, and around the edge of the Qinghai-Tibet Plateau, where are considered as the diversity center or micro-refuges of the host insects of O. sinensis. However, there was little genetic variation among host insects from 72.1% of all populations, indicating that the host species composition might be relatively simple in large-scale O. sinensis populations. All host insects are monophyletic except for those from four O. sinensis populations around Qinghai Lake. Significant phylogeographic structure (NST>GST, P<0.05) was revealed for the monophyletic host insects, and the three major phylogenetic groups corresponded with specific geographical areas. The divergence of most host insects was estimated to have occurred at ca. 3.7 Ma, shortly before the rapid uplift of the QTP. The geographical distribution and star-like network of the haplotypes implied that most host insects were derived from the relicts of a once-widespread host that subsequently became fragmented. Neutrality tests, mismatch distribution analysis, and expansion time estimation confirmed that most host insects presented recent demographic expansions that began ca. 0.118 Ma in the late Pleistocene. Therefore, the genetic diversity and distribution of the present-day insects should be attributed to effects of the Qinghai-Tibet Plateau uplift and glacial advance/retreat cycles during the Quaternary ice age. These results provide valuable information to guide

Mercury loading and methylmercury production and cycling in high-altitude lakes from the Western United States

USGS Publications Warehouse

Krabbenhoft, David P.; Olson, Mark L.; DeWild, John F.; Clow, David W.; Striegl, Robert G.; Dornblaser, Mark M.; Van Metre, Peter C.

2002-01-01

Studies worldwide have shown that mercury (Hg) is a ubiquitous contaminant, reaching even the most remote environments such as high-altitude lakes via atmospheric pathways. However, very few studies have been conducted to assess Hg contamination levels of these systems. We sampled 90 mid-latitude, high-altitude lakes from seven national parks in the western United States during a four-week period in September 1999. In addition to the synoptic survey, routine monitoring and experimental studies were conducted at one of the lakes (Mills Lake) to quantify MeHg fluxrates and important process rates such as photo-demethylation. Results show that overall, high-altitude lakes have low total mercury (HgT) and methylmercury (MeHg) levels (1.07 and 0.05 ng L-1, respectively), but a very good correlation of Hg to MeHg (r2= 0.82) suggests inorganic Hg(II) loading is a primary controlling factor of MeHg levels in dilute mountain lakes. Positive correlations were also observed for dissolved organic carbon (DOC) and both Hg and MeHg, although to a much lesser degree. Levels of MeHg were similar among the seven national parks, with the exception of Glacier National Park where lowerconcentrations were observed (0.02 ng L-1), and appear to be related to naturally elevated pH values there. Measured rates ofMeHg photo-degradation at Mills Lake were quite fast, and this process was of equal importance to sedimentation and stream flow for removing MeHg. Enhanced rates of photo-demethylation are likely an important reason why high-altitude lakes, with typically high water clarity and sunlight exposure, are low in MeHg.

MLVA and MLST typing of Brucella from Qinghai, China.

PubMed

Ma, Jun-Ying; Wang, Hu; Zhang, Xue-Fei; Xu, Li-Qing; Hu, Gui-Ying; Jiang, Hai; Zhao, Fang; Zhao, Hong-Yan; Piao, Dong-Ri; Qin, Yu-Min; Cui, Bu-Yun; Lin, Gong-Hua

2016-04-13

The Qinghai-Tibet Plateau (QTP) of China is an extensive pastoral and semi-pastoral area, and because of poverty and bad hygiene conditions, Brucella is highly prevalent in this region. In order to adequately prevent this disease in the QTP region it is important to determine the identity of Brucella species that caused the infection. A total of 65 Brucella isolates were obtained from human, livestock and wild animals in Qinghai, a Chinese province in east of the QTP. Two molecular typing methods, MLVA (multi-locus variable-number tandem-repeat analysis) and MLST (multi locus sequence typing) were used to identify the species and genotypes of these isolates. Both MLVA and MLST typing methods classified the 65 isolates into three species, B. melitensis, B. abortus and B. suis, which included 60, 4 and 1 isolates respectively. The MLVA method uniquely detected 34 (Bm01 ~ Bm34), 3 (Ba01 ~ Ba03), and 1 (Bs01) MLVA-16 genotypes for B. melitensis, B. abortus and B. suis, respectively. However, none of these genotypes exactly matched any of the genotypes in the Brucella2012 MLVA database. The MLST method identified five known ST types: ST7 and ST8 (B. melitensis), ST2 and ST5 (B. abortus), and ST14 (B. suis). We also detected a strain with a mutant type (3-2-3-2-?-5-3-8-2) of ST8 (3-2-3-2-1-5-3-8-2). Extensive genotype-sharing events could be observed among isolates from different host species. There were at least three Brucella (B. melitensis, B. abortus and B. suis) species in Qinghai, of which B. melitensis was the predominant species in the area examined. The Brucella population in Qinghai was very different from other regions of the world, possibly owing to the unique geographical characteristics such as extremely high altitude in QTP. There were extensive genotype-sharing events between isolates obtained from humans and other animals. Yaks, sheep and blue sheep were important zoonotic reservoirs of brucellosis causing species found in humans.

Repeated glacial lake outburst flood threatening the oldest Buddhist monastery in north-western Nepal

NASA Astrophysics Data System (ADS)

Kropáček, J.; Neckel, N.; Tyrna, B.; Holzer, N.; Hovden, A.; Gourmelen, N.; Schneider, C.; Buchroithner, M.; Hochschild, V.

2015-10-01

Since 2004, Halji village, home of the oldest Buddhist Monastery in north-western Nepal, has suffered from recurrent glacial lake outburst floods (GLOFs). A sudden englacial drainage of a supraglacial lake, located at a distance of 6.5 km from the village, was identified as the source of the flood. The topography of the lake basin was mapped by combining differential Global Positioning System (DGPS) measurements with a structure-from-motion (SFM) approach using terrestrial photographs. From this model the maximum filling capacity of the lake has been estimated as 1.06 ×106 m3 with a maximum discharge of 77.8 m3 s-1, calculated using the empiric Clague-Mathews formula. A simulation of the flooded area employing a raster-based hydraulic model considering six scenarios of discharge volume and surface roughness did not result in a flooding of the village. However, both the village and the monastery are threatened by undercutting of the river bank formed by unconsolidated sediments, as it already happened in 2011. Further, the comparison of the GLOF occurrences with temperature and precipitation from the High Asia Reanalysis (HAR) data set for the period 2001-2011 suggests that the GLOF is climate-driven rather than generated by an extreme precipitation event. The calculation of geodetic mass balance and the analysis of satellite images showed a rapid thinning and retreat of Halji Glacier which will eventually lead to a decline of the lake basin. As the basin will persist for at least several years, effective mitigation measures should be considered. A further reinforcement of the gabion walls was suggested as an artificial lake drainage is not feasible given the difficult accessibility of the glacier.

LANDSCAPE CHARACTER AND FISH ASSEMBLAGE STRUCTURE AND FUNCTION IN WESTERN LAKE SUPERIOR STREAMS: GENERAL RELATIONSHIPS AND IDENTIFICATION OF THRESHOLDS

EPA Science Inventory

As part of a comparative watershed project investigating land cover/land use disturbance gradients for streams in the western Lake Suerior Basin, we wanted to determine the influence of hydrogeomorphic region, forest fragmentation, and watershed storage on fish assemblage structu...

Passion: Burning in the West--An Investigation on College Students' Volunteer Teaching in Western China

ERIC Educational Resources Information Center

Zhen, Li

2008-01-01

In this article, the author investigates college students' volunteer teaching in Western China. A series of investigations were conducted in Chongqing, Sichuan, Guizhou, Yunnan, Shanxi, Gansu, Qinghai, Ningxia, and Xinjiang. The results showed that teaching by volunteer college students played a positive role in the development of local education…

Methods to assess natural and anthropogenic thaw lake drainage on the western Arctic coastal plain of northern Alaska

USGS Publications Warehouse

Hinkel, Kenneth M.; Jones, Benjamin M.; Eisner, Wendy R.; Cuomo, Chris J.; Beck, R.A.; Frohn, R.

2007-01-01

Thousands of lakes are found on the Arctic Coastal Plain of northern Alaska and northwestern Canada. Developed atop continuous permafrost, these thaw lakes and associated drained thaw lake basins are the dominant landscape elements and together cover 46% of the 34,570 km2western Arctic Coastal Plain (WACP). Lakes drain by a variety of episodic processes, including coastal erosion, stream meandering, and headward erosion, bank overtopping, and lake coalescence. Comparison of Landsat multispectral scanner (MSS) imagery from the mid-1970s to Landsat 7 enhanced thematic mapper (ETM+) imagery from around 2000 shows that 50 lakes completely or partially drained over the approximately 25 year period, indicating landscape stability. The lake-specific drainage mechanism can be inferred in some cases and is partially dependant on geographic settings conducive to active erosion such as riparian and coastal zones. In many cases, however, the cause of drainage is unknown. The availability of high-resolution aerial photographs for the Barrow Peninsula extends the record back to circa 1950; mapping spatial time series illustrates the dynamic nature of lake expansion, coalescence, and drainage. Analysis of these historical images suggests that humans have intentionally or inadvertently triggered lake drainage near the village of Barrow. Efforts to understand landscape processes and identify events have been enhanced by interviewing Iñupiaq elders and others practicing traditional subsistence lifestyles. They can often identify the year and process by which individual lakes drained, thereby providing greater dating precision and accuracy in assessing the causal mechanism. Indigenous knowledge has provided insights into events, landforms, and processes not previously identified or considered.

Critical nitrogen deposition loads in high-elevation lakes of the western US inferred from paleolimnological records

USGS Publications Warehouse

Saros, J.E.; Clow, D.W.; Blett, T.; Wolfe, A.P.

2011-01-01

Critical loads of nitrogen (N) from atmospheric deposition were determined for alpine lake ecosystems in the western US using fossil diatom assemblages in lake sediment cores. Changes in diatom species over the last century were indicative of N enrichment in two areas, the eastern Sierra Nevada, starting between 1960 and 1965, and the Greater Yellowstone Ecosystem, starting in 1980. In contrast, no changes in diatom community structure were apparent in lakes of Glacier National Park. To determine critical N loads that elicited these community changes, we modeled wet nitrogen deposition rates for the period in which diatom shifts first occurred in each area using deposition data spanning from 1980 to 2007. We determined a critical load of 1.4 kg N ha-1 year-1 wet N deposition to elicit key nutrient enrichment effects on diatom communities in both the eastern Sierra Nevada and the Greater Yellowstone Ecosystem. ?? 2010 Springer Science+Business Media B.V.

Role of rainwater induced subsurface flow in water-level dynamics and thermoerosion of shallow thermokarst ponds on the Northeastern Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

Pan, X.; Yu, Q.; You, Y.

2014-12-01

Understanding hydrological and thermal regimes of thermokarst lakes is of great importance for predicting their responses to climate change. However, mechanism of water-level dynamics and associated thermal effects on thermoerosion of thermokarst lakes are still not well understood on the Qinghai-Tibet Plateau (QTP). In this study, we investigate two typical shallow thermokarst ponds (namely small lakes) in a warm permafrost region with thick active layer on the northeastern QTP through quantifying water budget. Results demonstrate that, rainfall induced subsurface lateral flow dominates pond water-level regime. Annual variation of pond water-level relies on areal water budget of surrounding active layer, particularly the high variable of precipitation. Besides, it is worth noting the extraordinary warming during the late ice-cover period, because marked air gap between upper ice-cover and underlying water, led by the upward thawing of thick ice-cover, might result in greenhouse-like condition due to the unique weather that strong solar radiation and little snowpack. This hydrological mechanism also exerts evident impacts on thermal regime and thermoerosion of the shallow thermokarst ponds, and they are closely related to retreat of thermokarst pondshore and underlying permafrost degradation. These findings imply a localized model addressing the unique hydrological and thermal regimes of thermokarst lakes would be essential to study the evolution of these shallow rainwater dominated thermokarst ponds on the QTP.

Contrasting Distributions of Bacterial Branched Tetraethers along a Soil-River-Lake Transect in the Arid Region of Northwestern China

NASA Astrophysics Data System (ADS)

Lu, J.

2016-12-01

Understanding the transport of branched glycerol dialkyl glycerol tetraethers (brGDGTs) along the soil-river-lake transect is of vital importance, which helps discriminate the autochthonous from allochthonous contribution of brGDGTs in lake and river environment and favors the application of brGDGT-based proxies in paleo-reconstruction. We collected the sediment samples from the Qinghai Lake, the largest saline lake in China, as well as the river sediments and catchment soils, to examine the difference in the distribution of 5- vs. 6-methyl brGDGTs along the soil-river-lake transect. The brGDGT distributions were found to show a large variation along the transect, which can be reflected by the MBT'-derived indices and IR (isomer ratio) indices. There is a considerable difference in brGDGT distributions between soil and the river sediment. The inflowing rivers likely receive terrestrial brGDGT input to a variable degree. BrGDGTs in the Buha river are primarily of autochthonous origin whereas other ephemeral streams, like the Heima river, exhibit a similar brGDGT distribution to the surrounding soils, reflecting that these compounds are likely derived from soils. A higher quantity of 6-methyl brGDGTs and brGDGT-Ia was observed in the lake than in the river sediments, pointing to a preferential degradation of 5-methyl brGDGTs and/or an increase of in situ production of 6-methyl brGDGTs in the lake. Besides the difference in brGDGT distributions caused by the transportation and in situ production along the transect, we also identified the difference caused by several driving factors in different environments. In arid and alkaline soils, both CBT' and IR indices have strong correlations with soil pH even within the narrow pH range. However, we find a clear relationship of CBT with water salinity in Buha river. The difference in soil and river leads to a complicated interpretation for the CBT (CBT') index. In the lake, the MBT' (specially represented by MBT'5ME and MBT'6

[Molecular epidemiological study of measles viruses isolated in Qinghai Province during 2000-2011].

PubMed

Fan, Li-Xia; Ba, Zhuo-Ma; Zhao, Sheng-Cang; Yi, Hu; Jiang, Shuang-Ying; Zhang, Yan; Wang, Hui-Ling; Xu, Wen-Bo

2013-08-01

To carry out the molecular epidemiological study of the wild-type measles virus isolated in Qinghai Province during 2000-2011, and provide a scientific basis for the measles elimination. Measles viruses were isolated using B95a cell line or Vero/SLAM cell line from throat swabs collected from suspected measles cases during measles outbreak and sporadic in 6 prefectures during 2000-2011. The fragment of 696 nucleotides of N gene carboxy terminal was amplified by using RT-PCR methods. The PCR products were sequenced and analyzed. The phylogenetic tree was conducted with the viruses isolated in viruses from other province. Total 19 measles viruses were isolated during 2000-2011 in Qinghai province and all belong to genotype H1a. The results of phylogenetic tree showed that viruses in 2000-2005 and in 2009-2011 were distributed in two different lineages, and it revealed that these strains belonged to at least 2 viral transmission chains and the viruses circulated during 2000-2005 were not detected after 2005. Genotype H1a was the predominant genotype circulated in Qinghai province during 2000-2011. Qinghai measles virus strains had not evolved independently, but coevolved with the measles virus strains in other provinces in mainland China. The variation of important amino acid sites of measles virus should be continuous monitored and provide the scientific strategy for the measles elimination.

Analysis of long-term forest bird monitoring data from national forests of the western Great Lakes Region

Treesearch

Gerald J. Niemi; Robert W. Howe; Brian R. Sturtevant; Linda R. Parker; Alexis R. Grinde; Nicholas P. Danz; Mark D. Nelson; Edmund J. Zlonis; Nicholas G. Walton; Erin E. Gnass Giese; Sue M. Lietz

2016-01-01

Breeding bird communities in forests of the western Great Lakes region are among the most diverse in North America, but the forest environment in this region has changed dramatically during the past 150 years. To address concerns about loss of biodiversity due to ongoing forest harvesting and to better inform forest planning, researchers have systematically monitored...

Out of the tropics: the Pacific, Great Basin lakes, and late Pleistocene water cycle in the western United States.

PubMed

Lyle, Mitchell; Heusser, Linda; Ravelo, Christina; Yamamoto, Masanobu; Barron, John; Diffenbaugh, Noah S; Herbert, Timothy; Andreasen, Dyke

2012-09-28

The water cycle in the western United States changed dramatically over glacial cycles. In the past 20,000 years, higher precipitation caused desert lakes to form which have since dried out. Higher glacial precipitation has been hypothesized to result from a southward shift of Pacific winter storm tracks. We compared Pacific Ocean data to lake levels from the interior west and found that Great Basin lake high stands are older than coastal wet periods at the same latitude. Westerly storms were not the source of high precipitation. Instead, air masses from the tropical Pacific were transported northward, bringing more precipitation into the Great Basin when coastal California was still dry. The changing climate during the deglaciation altered precipitation source regions and strongly affected the regional water cycle.

Out of the tropics: the Pacific, Great Basin lakes, and late Pleistocene water cycle in the western United States

USGS Publications Warehouse

Lyle, Mitchell; Heusser, Linda; Ravelo, Christina; Yamamoto, Masanobu; Barron, John; Diffenbaugh, Noah S.; Herbert, Timothy; Andreasen, Dyke

2012-01-01

The water cycle in the western U.S. changed dramatically over glacial cycles. In the last 20,000 years, higher precipitation caused desert lakes to form which have since dried out. Higher glacial precipitation is hypothesized to result from a southward shift of Pacific winter storm tracks. We compared Pacific Ocean data to lake levels from the interior west and found that Great Basin lake high stands are older than coastal wet periods at the same latitude. Westerly storms were not the source of high precipitation. Instead, air masses from the tropical Pacific were transported northward, bringing more precipitation into the Great Basin when coastal California was still dry. The changing climate during the deglaciation altered precipitation source regions and strongly affected the regional water cycle.

Mapping risk of plague in Qinghai-Tibetan Plateau, China.

PubMed

Qian, Quan; Zhao, Jian; Fang, Liqun; Zhou, Hang; Zhang, Wenyi; Wei, Lan; Yang, Hong; Yin, Wenwu; Cao, Wuchun; Li, Qun

2014-07-10

Qinghai-Tibetan Plateau of China is known to be the plague endemic region where marmot (Marmota himalayana) is the primary host. Human plague cases are relatively low incidence but high mortality, which presents unique surveillance and public health challenges, because early detection through surveillance may not always be feasible and infrequent clinical cases may be misdiagnosed. Based on plague surveillance data and environmental variables, Maxent was applied to model the presence probability of plague host. 75% occurrence points were randomly selected for training model, and the rest 25% points were used for model test and validation. Maxent model performance was measured as test gain and test AUC. The optimal probability cut-off value was chosen by maximizing training sensitivity and specificity simultaneously. We used field surveillance data in an ecological niche modeling (ENM) framework to depict spatial distribution of natural foci of plague in Qinghai-Tibetan Plateau. Most human-inhabited areas at risk of exposure to enzootic plague are distributed in the east and south of the Plateau. Elevation, temperature of land surface and normalized difference vegetation index play a large part in determining the distribution of the enzootic plague. This study provided a more detailed view of spatial pattern of enzootic plague and human-inhabited areas at risk of plague. The maps could help public health authorities decide where to perform plague surveillance and take preventive measures in Qinghai-Tibetan Plateau.

Assessment of factors limiting algal growth in acidic pit lakes--a case study from Western Australia, Australia.

PubMed

Kumar, R Naresh; McCullough, Clint D; Lund, Mark A; Larranaga, Santiago A

2016-03-01

Open-cut mining operations can form pit lakes on mine closure. These new water bodies typically have low nutrient concentrations and may have acidic and metal-contaminated waters from acid mine drainage (AMD) causing low algal biomass and algal biodiversity. A preliminary study was carried out on an acidic coal pit lake, Lake Kepwari, in Western Australia to determine which factors limited algal biomass. Water quality was monitored to obtain baseline data. pH ranged between 3.7 and 4.1, and solute concentrations were slightly elevated to levels of brackish water. Concentrations of N were highly relative to natural lakes, although concentrations of FRP (<0.01 mg/L) and C (total C 0.7-3.7 and DOC 0.7-3.5 mg/L) were very low, and as a result, algal growth was also extremely low. Microcosm experiment was conducted to test the hypothesis that nutrient enrichment will be able to stimulate algal growth regardless of water quality. Microcosms of Lake Kepwari water were amended with N, P and C nutrients with and without sediment. Nutrient amendments under microcosm conditions could not show any significant phytoplankton growth but was able to promote benthic algal growth. P amendments without sediment showed a statistically higher mean algal biomass concentration than controls or microcosms amended with phosphorus but with sediment did. Results indicated that algal biomass in acidic pit lake (Lake Kepwari) may be limited primarily by low nutrient concentrations (especially phosphorus) and not by low pH or elevated metal concentrations. Furthermore, sediment processes may also reduce the nutrient availability.

Bottom-current and wind-pattern changes as indicated by Late Glacial and Holocene sediments from western Lake Geneva (Switzerland)

USGS Publications Warehouse

Girardclos, S.; Baster, I.; Wildi, W.; Pugin, A.; Rachoud-Schneider, A. -M.

2003-01-01

The Late-Glacial and Holocene sedimentary history of the Hauts-Monts area (western Lake Geneva, Switzerland) is reconstructed combining high resolution seismic stratigraphy and well-dated sedimentary cores. Six reflections and seismic units are defined and represented by individual isopach maps, which are further combined to obtain a three-dimensional age-depth model. Slumps, blank areas and various geometries are identified using these seismic data. The sediment depositional areas have substantially changed throughout the lake during the end of the Late-Glacial and the Holocene. These changes are interpreted as the result of variations in the intensity of deep lake currents and the frequency of strong winds determining the distribution of sediment input from the Versoix River and from reworking of previously deposited sediments within the lacustrine basin. The identified changes in sediment distribution allowed us to reconstruct the lake's deep-current history and the evolution of dominant strong wind regimes from the Preboreal to present times.

Effects of dreissenids on monitoring and management of fisheries in western Lake Erie

USGS Publications Warehouse

Stapanian, Martin A.; Kocovsky, Patrick M.

2013-01-01

Water clarity increased in nearshore areas of western Lake Erie by the early-1990s mainly as a result of the filtering activities of dreissenid mussels (Dreissena spp.), which invaded in the mid-1980s. We hypothesized that increased water clarity would result in greater trawl avoidance and thus reduced ability to capture fish in bottom trawls during daytime compared to nighttime. We examined this hypothesis by summarizing three analyses on fish data collected in western Lake Erie. First, we used a two-tiered modeling approach on the ration (R) of catch per hour (CPH) of age-0 yellow perch (Perca flavencens Mitchell) at night to CPH during daytime in 1961-2005. The best a priori and a posteriori models indicated a shift to higher CPH at night (R > 1) between 1990 and 1991, which corresponded to 3 years after the dreissenid invasion and when water clarity noticeably increased at nearshore sites. Secondly, we examined effects of nighttime sampling on estimates of abundance of age-2 and older yellow perch, which form the basis for recommended allowable harvest (RAH). When data from night sampling were included in models that predict abundance of age-2 yellow perch from indices of abundance of age-0 and age-1 yellow perch, predicted abundance was lower and model precision, as measured by r-squared, was higher compared to models that excluded data collected at night. Furthermore, the use of only CPH data collected at night typically resulted in lower estimates of abundance and more precise models compared to models that included CPH data collected during both daytime and nighttime. Thirdly, we used presence/absence data from paired bottom trawl samples to calculate an index of capture probability (or catchability) to determine if our ability to capture the four most common benthic species in western Lake Erie was affected by dreissenid-caused increased water clarity. Three species of fish(white perch, Morone americana Gmelin; yellow perch; and trout-perch, Percopsis

High-resolution seismic stratigraphy of an Holocene lacustrine delta in western Lake Geneva (Switzerland)

USGS Publications Warehouse

Baster, I.; Girardclos, S.; Pugin, A.; Wildi, W.

2003-01-01

A high-resolution seismic survey was conducted in western Lake Geneva on a small delta formed by the Promenthouse, the Asse and the Boiron rivers. This dataset provides information on changes in the geometry and sedimentation patterns of this delta from Late-glacial to Present. The geometry of the deposits of the lacustrine delta has been mapped using 300-m spaced grid lines acquired with a 12 kHz Echosounder subbottom profiler. A complete three dimensional image of the sediment architecture was reconstructed through seismic stratigraphic analysis. Six different delta lobes have been recognized in the prodelta area. Depositional centers and lateral extension of the delta have changed through time, indicating migration and fluctuation of river input as well as changes in lake currents and wind regime from the time of glacier retreat to the Present. The delta slope is characterized by a high instability causing stumps developing and by the accumulation of biogenic gas that prevents seismic penetration.

Some potential hazardous trace elements contamination and their ecological risk in sediments of western Chaohu Lake, China.

PubMed

Zheng, Liu-Gen; Liu, Gui-Jian; Kang, Yu; Yang, Ren-Kang

2010-07-01

The Chaohu is one of the largest five freshwater lakes in China. It provides freshwater for agriculture, life, and part of industry. The quality of water becomes worst and worst due to the toxic matter. In this study, we collected the samples from the sedimentary mud in the lake. The distribution of some potential hazardous trace elements (Cu, Ni, Cr, As, Pb, Cd, and Hg) in the sediments of western Chaohu Lake, has been determined and studied, and the enrichment factors, the index of geoaccumulation, and potential ecological risk were analyzed and calculated. The results show that: the levels of selected potential hazardous trace element vary from different sampling sites and significant anthropogenic impact of Pb and Cd occur in sediments. The contamination rank of Pb and Cd are moderate, and Pb has a light potential ecological risk, but Cd is heavy. The total potential ecological risk of the selected hazardous trace elements in this study in Chaohu Lake is moderate. Cluster and correlation analysis indicate that the selected potential hazardous trace element pollutant has different source and co-contamination also occur in sediments.

Mid-Late Holocene Asian monsoon variations recorded in the Lake Rara sediment, western Nepal

NASA Astrophysics Data System (ADS)

Nakamura, A.; Yokoyama, Y.; Maemoku, H.; Yagi, H.; Okamura, M.; Matsuoka, H.; Miyake, N.; Adhikari, D.; Dangol, V.; Miyairi, Y.; Obrochta, S.; Matsuzaki, H.; Ikehara, M.

2011-12-01

The Asian monsoon is an important component of the Earth's climate system to understand regional and global climate dynamics. While geological reconstructions indicate that the Asian summer monsoon intensity gradually decreased through the Holocene, a clear and coherent picture of millennial and centennial scale variability has yet to emerge (e.g., Overpeck and Cole, 2007). The Himalayas are a key location for understanding centennial to millennial scale variations in the Asian monsoon, yet few studies of the Holocene have been conducted in this sensitive area. Direct evidence for shifts in monsoonal wind strength is often limited to marine proxy records, while terrestrial reconstructions (e.g., lake levels and spleothems) focus on precipitation. Here, we present the first evidence of terrestrial summer monsoon wind strength changes from Lake Rara, western Nepal. The lake is located at 3,000m above sea level and has a maximum water depth of 168m. Lake Rara Mn/Ti data, a proxy for lake stratification, provide the first direct comparison of the Indian summer monsoon wind intensity between the terrestrial Himalayan region and the marine Arabian sea region (Gupta et al., 2003) during mid-late Holocene. Centennial to millennial scale variability found in those records are synchronous, with the weak wind intervals corresponding to drier periods of East Asian. Strong similarities between the Lake Rara monsoon record and the Dongge cave speleothems precipitation record (Wang et al., 2005) suggest that the influence of Indian summer monsoon penetrates into southeastern China, which should be taken into account when interpreting paleomonsoon reconstructions. Overpeck JT, Cole JE. 2007. Climate change - Lessons from a distant monsoon. Nature 445: 270-271. Gupta AK, Anderson DM, Overpeck JT. 2003. Abrupt changes in the Asian southwest monsoon during the Holocene and their links to the North Atlantic Ocean. Nature 421: 354-357. Wang YJ, Cheng H, Edwards RL, He YQ, Kong XG, An

How salt lakes affect atmospheric new particle formation: A case study in Western Australia.

PubMed

Kamilli, K A; Ofner, J; Krause, T; Sattler, T; Schmitt-Kopplin, P; Eitenberger, E; Friedbacher, G; Lendl, B; Lohninger, H; Schöler, H F; Held, A

2016-12-15

New particle formation was studied above salt lakes in-situ using a mobile aerosol chamber set up above the salt crust and organic-enriched layers of seven different salt lakes in Western Australia. This unique setup made it possible to explore the influence of salt lake emissions on atmospheric new particle formation, and to identify interactions of aqueous-phase and gas-phase chemistry. New particle formation was typically observed at enhanced air temperatures and enhanced solar irradiance. Volatile organic compounds were released from the salt lake surfaces, probably from a soil layer enriched in organic compounds from decomposed leaf litter, and accumulated in the chamber air. After oxidation of these organic precursor gases, the reaction products contributed to new particle formation with observed growth rates from 2.7 to 25.4nmh -1 . The presence of ferrous and ferric iron and a drop of pH values in the salt lake water just before new particle formation events indicated that organic compounds were also oxidized in the aqueous phase, affecting the new particle formation process in the atmosphere. The contribution of aqueous-phase chemistry to new particle formation is assumed, as a mixture of hundreds of oxidized organic compounds was characterized with several analytical techniques. This chemically diverse composition of the organic aerosol fraction contained sulfur- and nitrogen-containing organic compounds, and halogenated organic compounds. Coarse mode particles were analyzed using electron microscopy, energy dispersive X-ray spectroscopy and Raman spectroscopy. Ultra-high resolution mass spectrometry was applied to analyze filter samples. A targeted mass spectral analysis revealed the formation of organosulfates from monoterpene precursors and two known tracers for secondary organic aerosol formation from atmospheric oxidation of 1,8-cineole, which indicates that a complex interplay of aqueous-phase and gas-phase oxidation of monoterpenes contributes to

Sensitivity to acidification of subalpine ponds and lakes in north-western Colorado

USGS Publications Warehouse

Campbell, D.H.; Muths, E.; Turk, J.T.; Corn, P.S.

2004-01-01

Although acidifying deposition in western North America is lower than in many parts of the world, many high-elevation ecosystems there are extremely sensitive to acidification. Previous studies determined that the Mount Zirkel Wilderness Area (MZWA) has the most acidic snowpack and aquatic ecosystems that are among the most sensitive in the region. In this study, spatial and temporal variability of ponds and lakes in and near the MZWA were examined to determine their sensitivity to acidification and the effects of acidic deposition during and after snowmelt. Within the areas identified as sensitive to acidification based on bedrock types, there was substantial variability in acid-neutralizing capacity (ANC), which was related to differences in hydrological flowpaths that control delivery of weathering products to surface waters. Geological and topographic maps were of limited use in predicting acid sensitivity because their spatial resolution was not fine enough to capture the variability of these attributes for lakes and ponds with small catchment areas. Many of the lakes are sensitive to acidification (summer and autumn ANC < 100 µeq L−1), but none of them appeared to be threatened immediately by episodic or chronic acidification. In contrast, 22 ponds had minimum ANC < 30 µeq L−1, indicating that they are extremely sensitive to acidic deposition and could be damaged by episodic acidification, although net acidity (ANC < 0) was not measured in any of the ponds during the study. The lowest measured pH value was 5·4, and pH generally remained less than 6·0 throughout early summer in the most sensitive ponds, indicating that biological effects of acidification are possible at levels of atmospheric deposition that occurred during the study. The aquatic chemistry of lakes was dominated by atmospheric deposition and biogeochemical processes in soils and shallow ground water, whereas the aquatic chemistry of ponds was also affected by organic acids and

Polycyclic aromatic hydrocarbons and organochlorine pesticides in surface soils from the Qinghai-Tibetan plateau.

PubMed

Tao, Shu; Wang, Wentao; Liu, Wenxin; Zuo, Qian; Wang, Xilong; Wang, Rong; Wang, Bin; Shen, Guofeng; Yang, Yuanhe; He, Jin-shen

2011-01-01

Eighty eight surface soil samples were collected from the Qinghai-Tibetan Plateau (QTP) for determination of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethane and metabolites (DDXs) and hexachlorocyclohexane isomers (HCHs). The measured concentrations were 51.8 ± 38.5 ng g(-1), 0.329 ± 0.818 ng g(-1), and 0.467 ± 0.741 ng g(-1) as means and standard deviations of PAHs, DDXs, and HCHs, respectively, which were 1-2 orders of magnitude lower than those reported for eastern China. Significant differences were also revealed among four sub-areas within QTP. PAHs detected in the samples from the remote sub-areas of T'ang-ku-la/Hoh Xil Mountains and along the Qinghai-Tibet highway in the west and northwest of QTP were 1 order of magnitude lower than those from Lhasa and east Qinghai. The differences in soil OCPs among the sub-areas were 2-7 times. Soil PAHs were significantly correlated with emission density and soil organic carbon content (SOC), while OCPs were correlated significantly with the population density and SOC. Based on the calculated backward air mass trajectories and geographical distributions of emission and population, it was revealed that PAHs and OCPs accumulated in the soils in the west and northwest QTP were primarily from long-range transport and may represent the background levels of East Asia. This part of QTP can also serve as an important receptor area for regional or even global long-range transport study. The elevated concentrations of PAHs and OCPs in Lhasa and east Qinghai were mainly from local sources, while PAHs from adjacent Lanzhou area also contributed considerably to the accumulation of PAHs in east Qinghai.

Expressions of climate perturbations in western Ugandan crater lake sediment records during the last 1000 years

NASA Astrophysics Data System (ADS)

Mills, K.; Ryves, D. B.; Anderson, N. J.; Bryant, C. L.; Tyler, J. J.

2014-08-01

Equatorial East Africa has a complex regional patchwork of climate regimes, sensitive to climate fluctuations over a variety of temporal and spatial scales during the late Holocene. Understanding how these changes are recorded in and interpreted from biological and geochemical proxies in lake sedimentary records remains a key challenge to answering fundamental questions regarding the nature, spatial extent and synchroneity of climatic changes seen in East African palaeo-records. Using a paired lake approach, where neighbouring lakes share the same geology, climate and landscape, it might be expected that the systems will respond similarly to external climate forcing. Sediment cores from two crater lakes in western Uganda spanning the last ~1000 years were examined to assess diatom community responses to late Holocene climate and environmental changes, and to test responses to multiple drivers using redundancy analysis (RDA). These archives provide annual to sub-decadal records of environmental change. Lakes Nyamogusingiri and Kyasanduka appear to operate as independent systems in their recording of a similar hydrological response signal via distinct diatom records. However, whilst their fossil diatom records demonstrate an individualistic, indirect response to external (e.g. climatic) drivers, the inferred lake levels show similar overall trends and reflect the broader patterns observed in Uganda and across East Africa. The lakes appear to be sensitive to large-scale climatic perturbations, with evidence of a dry Medieval Climate Anomaly (MCA; ca. AD 1000-1200). The diatom record from Lake Nyamogusingiri suggests a drying climate during the main phase of the Little Ice Age (LIA) (ca. AD 1600-1800), whereas the diatom response from the shallower Lake Kyasanduka is more complex (with groundwater likely playing a key role), and may be driven more by changes in silica and other nutrients, rather than by lake level. The sensitivity of these two Ugandan lakes to regional

An Analysis of the Energy, Water, and Salt Balance of a Saline Lake in the Sandhills Region of Semi-Arid Western Nebraska (USA)

NASA Astrophysics Data System (ADS)

Ong, J.; Lenters, J. D.; Zlotnik, V. A.; Jones, S.

2009-12-01

The Sandhills region of western Nebraska comprises the largest stabilized dune field in the western hemisphere. Although situated in a semi-arid climate, the sandy soils allow a significant fraction of the ambient precipitation to drain through and recharge the underlying Ogallala aquifer. As part of the larger High Plains aquifer that extends from South Dakota down to Texas, the Sandhills region provides an abundant groundwater resource for the surrounding area and is heavily utilized for irrigation. Located within a semi-arid climate, fluctuations in groundwater recharge in the Sandhills are likely to be highly sensitive to changes in climate and the regional water balance. Important to this water balance are the numerous seepage lakes which exist throughout the region. Where present, however, these lakes evaporate rapidly as a result of the warm, dry, sunny, and windy conditions. Many of the lakes are highly saline and often support a diverse wetland ecosystem. A field study of one of these lakes was initiated in 2007 to examine the effects of climate variability on the energy and water balance of the lake. In particular, we measured incoming and outgoing solar and longwave radiation over the surface of the lake, as well as lake and sediment temperatures, salinity, water levels, and ancillary meteorological variables. The lake is shallow, with a depth of roughly 30 cm, but is observed to undergo significant variations in water level relative to its mean depth and is almost completely drying up during some periods. Salinity values undergo similarly large variations and are found to respond relatively rapidly to precipitation and evaporation “events.” Energy balance estimates of lake evaporation yield values that are well in excess of the ambient precipitation, suggesting significant inputs from groundwater. These evaporation measurements correspond closely with mass-transfer estimates, except during periods when the lake becomes dry enough to elevate surface

Burrowing mayflies as indicators of ecosystem health: Status of populations in two western Lake Superior embayments

USGS Publications Warehouse

Edsall, Thomas A.; Gorman, Owen T.; Evrard, Lori M.

2004-01-01

The U.S. Environmental Protection Agency and Environment Canada are supporting the development of indicators of ecosystem health that can be used to report on progress in restoring and maintaining the Great Lakes ecosystem, as called for in the Great Lakes Water Quality Agreement between the United States and Canada. One indicator under development for Great Lakes mesotrophic environments is based on burrowing mayflies (Hexagenia: Ephemeroptera: Ephemeridae). In this paper, we report the results of a benthic survey in spring 2002 to determine the status of nymphal populations of Hexagenia in two western Lake Superior embayments, the St. Louis River estuary, an area with significant water-use impairments, and Chequamegon Bay, an area with no known water-use impairments. Ponar grab samples collected throughout these embayments showed nymphs were generally abundant in finely particulate, cohesive substrate (clay or mixtures of clay and sand) in both embayments. However, in the St. Louis River estuary nymphs were absent in those preferred substrates at 11 stations in the eastern portion of St. Louis Bay and the adjoining northwestern portion of the Duluth-Superior Harbor, where the sediments were variously contaminated with visible amounts of taconite pellets, paint chips, oil, or combusted coal waste (clinkers). Our results suggest that human activities have rendered those portions of the St. Louis River estuary unsuitable for habitation by Hexagenia nymphs and we recommend that trend monitoring of the nymphal population there be conducted to permit reporting on progress in restoring and maintaining the health and integrity of this Great Lakes ecosystem embayment, consistent with the intent of the Great Lakes Water Quality Agreement.

[The epidemiology and etiology research of Tibetan sheep plague in Qinghai plateau].

PubMed

Wei, Baiqing; Xiong, Haoming; Yang, Xiaoyan; Yang, Yonghai; Qi, Meiying; Jin, Juan; Xin, Youquan; Li, Xiang; Yang, Hanqing; Han, Xiumin; Dai, Ruixia

2015-03-01

To identify the epidemiology and etiology characteristics of Tibetan sheep plague in Qinghai plateau. The background materials of Qinghai Tibetan sheep plague found during 1975 to 2009 were summarized, the regional, time and interpersonal distribution, infection routes, ecological factors for the spread were used to analyze; followed by choosing 14 Yersinia pestis strains isolated from such sheep for biochemical test, toxicity test, virulence factors identification, plasmid analysis, and DFR genotype. From 1975 to 2009, 14 Yersinia pestis strains were isolated from Tibetan sheep in Qinghai province. Tibetan sheep, as the infection source, had caused 10 cases of human plague, 25 plague patients, and 13 cases of death. All of the initial cases were infected due to eating Tibetan sheep died of plague; followed by cases due to contact of plague patients, while all the initial cases were bubonic plague. Cases of bubonic plague developed into secondary pneumonic plague and septicemia plague were most popular and with high mortality. Most of the Tibetan sheep plague and human plague occurred in Gannan ecological zone in southern Gansu province, which was closely related to its unique ecological and geographical landscape. Tibetan sheep plague coincided with human plague caused by Tibetan sheep, especially noteworthy was that November (a time for marmots to start their dormancy) witnesses the number of Yersinia pestis strains isolated from Tibetan sheep and human plague cases caused by Tibetan sheep. This constituted the underlying cause that the epidemic time of Tibetan sheep plague lags obviously behind that of the Marmot plague. It was confirmed in the study that all the 14 strains were of Qinghai-Tibet Plateau ecotype, with virulence factors evaluation and toxicity test demonstrating strains as velogenic. As found in the (Different Region) DFR genotyping, the strains isolated from Yushu county and Zhiduo county were genomovar 5, the two strain isolated from Nangqian

Research on Synchronous Coordination Development of Tourism-Economy-Environment System in Qinghai Section of Silk Road

NASA Astrophysics Data System (ADS)

Xue, Huaju

2018-01-01

Using coupling theory in physics, the paper analyzed the relationship of coordinated development of tourism-economy-environment system (abbr. TEES) in Qinghai. Results showed the comprehensive evaluation of Qinghai TEES has been improved greatly from 2000 to 2014. However, coupling degree has still been in the running-in stage and coordination degree only arrives at the primary coordination level, the development of economy and tourism has exceeded the threshold of ecological environment after 2008, and the ecological environment has become the bottleneck restricting the further improvement of coupling coordination. In the future, Qinghai must change its mode of development and focus on industrial upgrading and transformation so as to promote the harmonious and sustainable development of TEES in the Silk Road.

Recent geologic history of lake Atitlán, a caldera lake in western Guatemala

USGS Publications Warehouse

Newhall, C.G.; Paull, C.K.; Bradbury, J.P.; Higuera-Gundy, A.; Poppe, L.J.; Self, S.; Bonar, Sharpless N.; Ziagos, J.

1987-01-01

Heat-flow measurements inside and just outside the caldera are high (290 and 230 mW m−2), suggesting hydrothermal convection and a shallow heat source. High heat flow, a geological record of post-caldera silicic eruptions, and unexplained fluctuations of lake level (episodic tumescence ofthe lake floor?) suggest that magma remains beneath Lake Atitlán and that future eruptions are possible.

In-Lake Processes Offset Increased Terrestrial Inputs of Dissolved Organic Carbon and Color to Lakes

PubMed Central

Köhler, Stephan J.; Kothawala, Dolly; Futter, Martyn N.; Liungman, Olof; Tranvik, Lars

2013-01-01

Increased color in surface waters, or browning, can alter lake ecological function, lake thermal stratification and pose difficulties for drinking water treatment. Mechanisms suggested to cause browning include increased dissolved organic carbon (DOC) and iron concentrations, as well as a shift to more colored DOC. While browning of surface waters is widespread and well documented, little is known about why some lakes resist it. Here, we present a comprehensive study of Mälaren, the third largest lake in Sweden. In Mälaren, the vast majority of water and DOC enters a western lake basin, and after approximately 2.8 years, drains from an eastern basin. Despite 40 years of increased terrestrial inputs of colored substances to western lake basins, the eastern basin has resisted browning over this time period. Here we find the half-life of iron was far shorter (0.6 years) than colored organic matter (A420 ; 1.7 years) and DOC as a whole (6.1 years). We found changes in filtered iron concentrations relate strongly to the observed loss of color in the western basins. In addition, we observed a substantial shift from colored DOC of terrestrial origin, to less colored autochthonous sources, with a substantial decrease in aromaticity (-17%) across the lake. We suggest that rapid losses of iron and colored DOC caused the limited browning observed in eastern lake basins. Across a wider dataset of 69 Swedish lakes, we observed greatest browning in acidic lakes with shorter retention times (< 1.5 years). These findings suggest that water residence time, along with iron, pH and colored DOC may be of central importance when modeling and projecting changes in brownification on broader spatial scales. PMID:23976946

Population Differentiations and Phylogenetic Analysis of Tibet and Qinghai Tibetan Groups Based on 30 InDel Loci.

PubMed

Guo, Yuxin; Shen, Chunmei; Meng, Haotian; Dong, Qian; Kong, Tingting; Yang, Chunhua; Wang, Hongdan; Jin, Rui; Zhu, Bofeng

2016-12-01

In recent years, Insertion/Deletion (InDel) polymorphisms have become a hot area of forensic research. In this study, 30 InDel loci were selected to investigate the genetic polymorphisms of Tibetan groups, which are from Tibet Autonomous Region and Qinghai province of China, and explore the genetic relationships between Tibetan groups and other groups. Allele frequencies of the 30 InDel loci ranged from 0.1219 (HLD111) to 0.5609 (HLD57) in the Tibet Tibetan group and 0.1639 (HLD118) to 0.5655 (HLD124) in the Qinghai Tibetan group. The combined power of discrimination, matching probability, and power of exclusion were 0.999999999986, 0.999999988, and 0.9913 in the Tibet Tibetan group, respectively, and 0.99999999999204, 0.9999999796, and 0.9862 in the Qinghai Tibetan group. The results of principal component analysis, phylogenetic tree, and population structure demonstrated that the four Tibetan groups (Tibetan1, Tibetan2, Tibet, and Qinghai Tibetan groups) clustered together and had relatively close genetic relationships with nine Asian groups and then European and Amerindian groups.

Long-Term Remote Monitoring of Three Typical Lake Area Variations in the Northwest China Over the Past 40 Years

NASA Astrophysics Data System (ADS)

Liu, Y.; Lu, Y.; Li, Y.; Yue, H.

2018-04-01

water resources management and sustainable development strategy, but also provide reference for assessing the impact of climate change and human activities. This paper selects three inland lakes in Northwest China, using Landsat MSS/TM/ETM+/OLI data from 1970 to 2015, Normalized Difference Water Index (NDWI) and Modified Normalized Difference Water Index (MNDWI) were used to extract lake area and analysed the dynamic trends. Meteorological station rainfall, evaporation and other meteorological data of the lakes were used to analyse reasons for the area change. The results showed that area of Hongjiannao Lake in the past 40 a was reduced, the groundwater impoundment and underground coal mining are the main cause of area reduction; the area of Bosten Lake in recent 40 a showed a decreasing trend after the first increase, the area was mainly affected by the surface runoff and snowmelt; the area of Qinghai Lake in the past 40 a shows a trend of decreasing first and then increasing, the change of its area is mainly affected by regional precipitation and the inflow.

Supraglacial Lakes in the Percolation Zone of the Western Greenland Ice Sheet: Formation and Development using Operation IceBridge Snow Radar and ATM (2009-2014)

NASA Astrophysics Data System (ADS)

Chen, C.; Howat, I. M.; de la Peña, S.

2015-12-01

Surface meltwater lakes on the Greenland Ice Sheet have appeared at higher elevations, extending well into the percolation zone, under recent warming, with the largest expansion occurring in the western Greenland Ice Sheet. The conditions that allow lakes to form atop firn are poorly constrained, but the formation of new lakes imply changes in the permeability of the firn at high elevations, promoting meltwater runoff. We explore the formation and evolution of new surface lakes in this region above 1500 meters, using a combination of satellite imagery and repeat Snow (2-6.5 GHz) radar echograms and LIDAR measurements from NASA's Operation IceBridge of 2009-2014. We identify conditions for surface lake formation at their farthest inland extent and suggest behaviors of persistence and lake drainage are due to differences in regional ice dynamics.

Distribution and abundance of larval fish in the nearshore waters of western Lake Huron

USGS Publications Warehouse

O'Gorman, Robert

1983-01-01

Ichthyoplankton was collected at 17 nearshore (bottom depth ≥5 m but ≤10 m) sites in western Lake Huron during 1973–75 with a 0.5-m net of 351-micron mesh towed at 99 m/min. Larvae of rainbow smelt (Osmerus mordax) dominated late spring and early summer catches and larvae of alewives (Alosa pseudoharengus) the midsummer catches. Larval yellow perch (Perca flavescens) were caught in early summer but were rarely the dominant species. The time of spawning and hatching, and thus occurrence of larvae, differed between areas but was less variable for alewives than for yellow perch. The appearance of larvae in Saginaw Bay was followed successively by their appearance in southern, central, and northern Lake Huron. Rainbow smelt were most abundant in northern Lake Huron and yellow perch and alewives in inner Saginaw Bay. Densities of either rainbow smelt or alewives occasionally exceeded 1/m3, whereas those of yellow perch never exceeded 0.1/m3. Abundance of alewives was usually highest 1 to 3 m beneath the surface and that of rainbow smelt 2 to at least 6 m beneath the surface. Important nursery areas of rainbow smelt were in bays and off irregular coastlines and those of yellow perch were in bays. All nearshore waters seemed equally important as nursery areas of alewives.

Mono Lake, California

NASA Image and Video Library

2017-03-24

In eastern California, along the western edge of the Great Basin, sits Mono Lake. This is a salty remnant of a wetter era. Estimates are that the lake existed for at least 760,000 years. Now surrounded by mountain ranges, however, Mono Lake has no outlet; water entering the lake can only evaporate away, so Mono Lake is saltier than the ocean. South of the lake appear some of the geologic features known as Mono Craters. Geologists estimate that the Mono Craters last erupted about 650 years ago. The image was acquired July 7, 2016, covers an area of 22.6 by 34 km, and is located at 37.9 degrees north, 119 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA21518

Metal ion complex formation in small lakes of the Western Siberian Arctic zone

NASA Astrophysics Data System (ADS)

Kremleva, Tatiana; Dinu, Marina

2017-04-01

be predominantly in free, ionic or bound form with inorganic ligands. This state means paradox consequence that the increase of dissolved Fe content will lead to toxicity rise of other elements having less affinity to organic material. For surface waters of Western Siberian Arctic zone this situation is quite common. The total concentration of iron and aluminum ions in most lakes of tundra and northern taiga zones is approximately equal to water complexing ability. From the other side humic substances participation in inactivation of other more toxic metals (Cu, Pb, Cd, Cr, Ni et al.) will be poor. Arctic part of Western Siberia undergoes significant anthropogenic load due to extensive oil and gas recovery in this zone. Surface waters of Western Siberia are characterized by high natural content of iron, aluminum and copper ions and anthropogenic load of heavy metals makes the situation more serious.

Food of forage fishes in western Lake Erie, 1975-76

USGS Publications Warehouse

Muth, Kenneth M.; Busch, Wolf-Dieter N.

1989-01-01

In western Lake Erie in the summer and fall of 1975–1976, food eaten by seven forage fishes—emerald shiner (Notropis atherinoides), spottail shiner (Notropis hudsonius), trout-perch (Percopsis omiscomaycus), andyoung-of-the-year (YOY) of alewife (Alosa pseudoharengus), gizzard shad (Dorosoma cepedianum), white bass (Morone chrysops), and freshwater drum (Aplodi-notus grunniens)—was divided among six major taxa: Cladocera, Copepoda, Diptera, Ostracoda, Amphipoda, and Algae. In addition, fish were eaten by YOY white bass, and Rotifera were consumed by YOY gizzard shad. Interspecies diet overlap indices, calculated to compare the food of the different species and to evaluate diet similarities, were usually highest for YOY white bass and YOY freshwater drum when compared with the other species and usually lowest between emerald shiners and all other forage fishes. Understanding the feeding interactions among fishes that could influence production at the forage-food level of the food web could provide insight into how cascading trophic interactions influence the production of piscivorous predators.

LAKE HERRING (COREGONUS ARTEDI) AND RAINBOW SMELT (OSMERUS MORDAX) DIETS IN LAKE SUPERIOR

EPA Science Inventory

This manuscript reports on the diets of lake herring and rainbow smelt, currently the two dominant forage fish species (fish that are food for game fishes) in western Lake Superior. Despite the pelagic nature of both these species, they have substantially different diets and henc...

Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

NASA Astrophysics Data System (ADS)

Audry, S.; Pokrovsky, O. S.; Shirokova, L. S.; Kirpotin, S. N.; Dupré, B.

2011-11-01

This study reports the very first results on high-resolution sampling of sediments and their porewaters from three thermokarst (thaw) lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i) document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii) characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC) stock in thermokarst lake sediments of 14 ± 2 kg m-2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM) mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways from nitrate and sulfate to Fe- and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions was suggested. This shift was likely promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe- and Mn-oxyhydroxides) and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe- and Mn-oxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of authigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all stages of ecosystem development

Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

NASA Astrophysics Data System (ADS)

Audry, S.; Pokrovsky, O. S.; Shirokova, L. S.; Kirpotin, S. N.; Dupré, B.

2011-08-01

This study reports the very first results on high-resolution sampling of sediments and their porewaters from three thermokarst (thaw) lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i) document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii) characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC) stock in thermokarst lake sediments of 14 ± 2 kg m-2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM) mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways was evidenced from nitrate and sulfate to Fe- and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions. This shift was promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe- and Mn-oxyhydroxides) and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe- and Mn-oxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of authigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all stages of ecosystem development, the

Microbial community structure and diversity within hypersaline Keke Salt Lake environments.

PubMed

Han, Rui; Zhang, Xin; Liu, Jing; Long, Qifu; Chen, Laisheng; Liu, Deli; Zhu, Derui

2017-11-01

Keke Salt Lake is located in the Qaidamu Basin of China. It is a unique magnesium sulfate-subtype hypersaline lake that exhibits a halite domain ecosystem, yet its microbial diversity has remained unstudied. Here, the microbial community structure and diversity was investigated via high-throughput sequencing of the V3-V5 regions of 16S rRNA genes. A high diversity of operational taxonomic units was detected for Bacteria and Archaea (734 and 747, respectively), comprising 21 phyla, 43 classes, and 201 genera of Bacteria and 4 phyla, 4 classes, and 39 genera of Archaea. Salt-saturated samples were dominated by the bacterial genera Bacillus (51.52%-58.35% relative abundance), Lactococcus (9.52%-10.51%), and Oceanobacillus (8.82%-9.88%) within the Firmicutes phylum (74.81%-80.99%), contrasting with other hypersaline lakes. The dominant Archaea belonged to the Halobacteriaceae family, and in particular, the genera (with an abundance of >10% of communities) Halonotius, Halorubellus, Halapricum, Halorubrum, and Natronomonas. Additionally, we report the presence of Nanohaloarchaeota and Woesearchaeota in Qinghai-Tibet Plateau lakes, which has not been previously documented. Total salinity (especially Mg 2+ , Cl - , Na + , and K + ) mostly correlated with taxonomic distribution across samples. These results expand our understanding of microbial resource utilization within hypersaline lakes and the potential adaptations of dominant microorganisms that allow them to inhabit such environments.

Age, growth and sex composition of the American smelt Osmerus mordax(Mitchill), of western Lake Superior

USGS Publications Warehouse

Bailey, Merryll M.

1964-01-01

This study is based on 4,561 smelt collected in Chequamegon Bay, the Apostle Islands, the Brule River, and Superior Harbor, all in western Lake Superior. Commercial production in the Great Lakes (U.S. and Canada combined) reached a peak of nearly 16 million pounds in 1960. Production in Lake Superior has generally been small but increased during the 1950's to reach 948,000 pounds in 1960. All O-group and spring I-group smelt had scales with sufficient sculpturing to permit detection of the first annulus. Annulus formation began after 6 June in 1960. In 1961, all smelt had completed the annulus by 24 August. The body-scale relation is a straight line with an intercept of -0.9 inch on the axis of fish length. The weight of western Lake Superior smelt increased as the 2.952 power of the length. A large range of length in each age group and resulting overlap of age-groups II-VI made length a poor index of age. Female smelt grew faster than males after the second year and dominated strongly in age-groups IV-VII. Both sexes made their best annual growth in length (3.3 inches) during their second year of life; the largest weight increments (0.74 ounce, males; 0.85 ounce, females) came in the third year. Best production from a commercial pound net in 1961 occurred when the sex ratios of spawning smelt were nearest 50:50. Spawning male smelt were consistently shorter than females and the average lengths of both sexes decreased as the spawning season progressed. Shortest mature smelt of each sex were 5.0 to 5.2 inches but the males are probably the first to reach 100 percent maturity. All year-old smelt were immature. Among 2-year-old fish, 40.7 per cent of the males and 17.7 percent of the females had reached maturity. All smelt more than 2 years old were mature. Ovaries of 10 smelt contained an average of 31,338 eggs for fish 7.3 to 8.8 inches long.

27 CFR 9.177 - Alexandria Lakes.

Code of Federal Regulations, 2010 CFR

2010-04-01

... and then northeasterly along the western shore of Lake Carlos on to the Alexandria East, Minn. map... eastern shoreline; then (11) South along Lake Ida's eastern shoreline, then onto the Alexandria West, Minn...

Seismic investigation of Lake Issyk-Kul, Kyrgyzstan

NASA Astrophysics Data System (ADS)

Gebhardt, C.; Naudts, L.; De Mol, L.; De Batist, M.

2012-04-01

Lake Issyk-Kul is located in an intramontane basin of the Tien Shan mountains in Kyrgyzstan, Central Asia. It has formed in a tectonically active region with W-E striking major thrust zones north and south of the lake. The lake's modern surface level is at 1607 m above sea level, maximum depth in the central basin of the lake is roughly 670 m, and the total water volume is around 1736 km3. The lake is elongated with 180 km in west-east and 60 km in south-north direction. With a surface area of 6232 km2, Lake Issyk-Kul is the second largest lake in the higher altitudes. The lake is characterized by two large delta areas at its western and eastern end, with the deltaic area being as wide as up to 60 km in the eastern and 40 km in the western part, and by steep slopes at the northern and southern shore with only a rather narrow shallower shelf area. The lake contains the sediments of the past up to several million years, and has been proposed as a future target for deep drilling within ICDP. Three seismic surveys by Russian and Belgian groups in 1982, 1997 and 2001 revealed a thick sediment infill in Lake Issyk-Kul. At both the western and the eastern end of the lake, large delta systems were formed by actual and previous inlets, namely the Tyup and Djyrgalan rivers in the eastern part of the lake (still active) and the Chu River at the western end (currently bypassing the lake). Large sub-aquatic channel systems are visible in the lake's bathymetry in the shallower part of the delta systems close to the river mouths. They were quite likely formed by these rivers during a former lake level lowstand. The delta system consists of stacked prograding delta lobes with a characteristic topset-foreset-bottomset configuration. These lobes together with sub-aerial terraces found at several spots around the lake witness lake level fluctuations of up to >400 m. The sediments in the central plain of Lake Issyk-Kul are mainly well-layered with many turbiditic sequences

Molecular identification of Echinococcus species from eastern and southern Qinghai, China, based on the mitochondrial cox1 gene.

PubMed

Ma, Junying; Wang, Hu; Lin, Gonghua; Craig, Philip S; Ito, Akira; Cai, Zhenyuan; Zhang, Tongzuo; Han, Xiumin; Ma, Xiao; Zhang, Jingxiao; Liu, Yufang; Zhao, Yanmei; Wang, Yongshun

2012-07-01

The Qinghai-Tibetan Plateau (QTP, in western China), which is the largest and highest plateau on Earth, is a highly epidemic region for Echinococcus spp. We collected 70 Echinococcus samples from humans, dogs, sheep, yaks, plateau pikas, and voles in eastern and southern Qinghai and genotyped them using the mitochondrial DNA marker cytochrome oxidase subunit I gene and maximum parsimony and Bayesian reconstruction methods. Based on the 792-bp sequence matrix, we recorded 124 variable sites, of which, 115 were parsimony-informative. Thirty-four haplotypes (H1-H34) were detected, of which H1-H15, H16-H17, and H18-H34 belonged to Echinococcus shiquicus, Echinococcus multilocularis, and Echinococcus granulosus, respectively. Within 26 human isolates, three were identified as E. multilocularis and 23 were E. granulosus. We also detected a dual infection case in a dog with E. multilocularis and E. granulosus. The intraspecific haplotype (Hd ± SD) and nucleotide (Nd ± SD) diversity of E. shiquicus (0.947 ± 0.021; 0.00441 ± 0.00062) was higher than that for E. granulosus (0.896 ± 0.038; 0.00221 ± 0.00031) and E. multilocularis (0.286 ± 0.196; 0.00036 ± 0.00025). Moreover, the haplotype network of E. shiquicus showed a radial feature rather than a divergent feature in a previous study, indicating this species in the QTP has also evolved with bottleneck effects.

Lake level variability in Silver Lake, Michigan: a response to fluctuations in lake levels of Lake Michigan

USGS Publications Warehouse

Fisher, Timothy G.; Loope, Walter L.

2004-01-01

Sediment from Silver Lake, Michigan, can be used to constrain the timing and elevation of Lake Michigan during the Nipissing transgression. Silver Lake is separated from Lake Michigan by a barrier/dune complex and the Nipissing, Calumet, and Glenwood shorelines of Lake Michigan are expressed landward of this barrier. Two Vibracores were taken from the lake in February 2000 and contain pebbly sand, sand, buried soils, marl, peat, and sandy muck. It is suggested here that fluctuations in the level of Lake Michigan are reflected in Silver Lake since the Chippewa low phase, and possibly at the end of the Algonquin phase. An age of 12,490 B.P. (10,460±50 14C yrs B.P.) on wood from a buried Entisol may record the falling Algonquin phase as the North Bay outlet opened. A local perched water table is indicated by marl deposited before 7,800 B.P. and peat between 7,760-7,000 B.P. when Lake Michigan was at the low elevation Chippewa phase. Continued deepening of the lake is recorded by the transition from peat to sandy muck at 7,000 B.P. in the deeper core, and with the drowning of an Inceptisol nearly 3 m higher at 6,410 B.P. in the shallower core. A rising groundwater table responding to a rising Lake Michigan base level during the Nipissing transgression, rather than a response to mid-Holocene climate change, explains deepening of Silver Lake. Sandy muck was deposited continually in Silver Lake between Nipissing and modern time. Sand lenses within the muck are presumed to be eolian in origin, derived from sand dunes advancing into the lake on the western side of the basin.

Mercury sedimentation in lakes in western Whatcom County, Washington, USA and its relation to local industrial and municipal atmospheric sources

USGS Publications Warehouse

Paulson, A.J.; Norton, D.

2008-01-01

Concentrations of mercury (Hg) were measured in six dated cores from four lakes in western Whatcom County, Washington, USA, that were at various bearings from a chlor-alkali plant, two municipal waste incinerators and a municipal sewage sludge incinerator. The importance of atmospheric emissions of Hg from these local municipal and industrial sources was evaluating by comparing the temporal trends in sedimentation of the lake cores with the emission history of each Hg species and by examining the geographical distribution of Hg sedimentation in relation to the region's primary wind pattern. Local municipal and industrial sources of atmospheric Hg were not responsible for the majority of the Hg in the upper layer of sediments of Whatcom County lakes because of (1) the significant enrichment of Hg in lake sediments prior to emissions of local industrial and municipal sources in 1964, (2) smaller increases in Hg concentrations occurred after 1964, (3) the similarity of maximum enrichments found in Whatcom County lakes to those in rural lakes around the world, (4) the inconsistency of the temporal trends in Hg sedimentation with the local emission history, and (5) the inconsistency of the geographic trends in Hg sedimentation with estimated deposition. Maximum enrichment ratios of Hg in lake sediments between 2 and 3 that are similar to rural areas in Alaska, Minnesota, and New England suggest that global sources of Hg were primarily responsible for increases of Hg in Whatcom County lakes beginning about 1900. ?? 2007 GovernmentEmployee: U.S. Government, Department of Interior, U.S. Geological Survey.

Permafrost and lakes control river isotope composition across a boreal Arctic transect in the Western Siberian lowlands

NASA Astrophysics Data System (ADS)

Ala-aho, P.; Soulsby, C.; Pokrovsky, O. S.; Kirpotin, S. N.; Karlsson, J.; Serikova, S.; Manasypov, R.; Lim, A.; Krickov, I.; Kolesnichenko, L. G.; Laudon, H.; Tetzlaff, D.

2018-03-01

The Western Siberian Lowlands (WSL) store large quantities of organic carbon that will be exposed and mobilized by the thawing of permafrost. The fate of mobilized carbon, however, is not well understood, partly because of inadequate knowledge of hydrological controls in the region which has a vast low-relief surface area, extensive lake and wetland coverage and gradually increasing permafrost influence. We used stable water isotopes to improve our understanding of dominant landscape controls on the hydrology of the WSL. We sampled rivers along a 1700 km South-North transect from permafrost-free to continuous permafrost repeatedly over three years, and derived isotope proxies for catchment hydrological responsiveness and connectivity. We found correlations between the isotope proxies and catchment characteristics, suggesting that lakes and wetlands are intimately connected to rivers, and that permafrost increases the responsiveness of the catchment to rainfall and snowmelt events, reducing catchment mean transit times. Our work provides rare isotope-based field evidence that permafrost and lakes/wetlands influence hydrological pathways across a wide range of spatial scales (10-105 km2) and permafrost coverage (0%-70%). This has important implications, because both permafrost extent and lake/wetland coverage are affected by permafrost thaw in the changing climate. Changes in these hydrological landscape controls are likely to alter carbon export and emission via inland waters, which may be of global significance.

Fecundity of walleyes in western Lake Erie, 1966 and 1990-91

USGS Publications Warehouse

Muth, Kenneth M.; Ickes, Brian S.

1993-01-01

Ovaries were collected from walleyes (Stizostedion vitreum vitreum) in western Lake Erie just prior to spawning in 1990 and 1991 to determine current fecundity. Results were compared with fecundity determined in 1966 prior to stock rehabilitation when walleye abundance was lower and fish size at age was greater. Fecundity estimates determined from 121 fish aged 3-10 ranged from 53,000 to 426,000 eggs per female. Increases in egg production correlated with increases in length and weight, and weight accounting for most of the variability. In 1990-91 the mean egg production of the dominant age groups of spawners (ages 4 to 8) was approximately 25% lower than fishes of similar age in 1966. The mean egg diameter in 1990-91 (1.63 mm) was not related to the size or age of the fish and was not significantly smaller than the egg diameter in 1966 (1.72 mm).

Remote sensing of severe convective storms over Qinghai-Xizang Plateau

NASA Technical Reports Server (NTRS)

Hung, R. J.; Liu, J. M.; Tsao, D. Y.; Smith, R. E.

1984-01-01

The American satellite, GOES-1 was moved to the Indian Ocean at 58 deg E during the First GARP Global Experiment (FGGE). The Qinghai-Xizang Plateau significantly affects the initiation and development of heavy rainfall and severe storms in China, just as the Rocky Mountains influence the local storms in the United States. Satelite remote sensing of short-lived, meso-scale convective storms is particularly important for covering a huge area of a high elevation with a low population density, such as the Qinghai-Xizang Plateau. Results of this study show that a high growth rate of the convective clouds, followed by a rapid collapse of the cloud top, is associated with heavy rainfall in the area. The tops of the convective clouds developed over the Plateau lie between the altitudes of the two tropopauses, while the tops of convective clouds associated with severe storms in the United States usually extend much above the tropopause.

Hydrothermal Petroleum in Active Continental Rift: Lake Chapala, Western Mexico, Initial Results.

NASA Astrophysics Data System (ADS)

Zarate-del Valle, P. F.; Simoneit, B. R.; Ramirez-Sanchez, H. U.

2003-12-01

Lake Chapala in western Mexico is located partially in the Citala Rift, which belongs to the well-known neotectonic Jalisco continental triple junction. The region is characterized by active volcanism (Ceboruco, Volcan de Fuego), tectonic (1995 earthquake, M=8, 40-50 mm to SW) and hydrothermal (San Juan Cosala & Villa Corona spas and La Calera sinter deposit) activities. Hydrothermal petroleum has been described in active continental rift (East African Rift) and marine spreading zones (Guaymas Basin, Gulf of California). In 1868 the Mexican local press reported that manifestations of bitumen were appearing in front of the Columba Cap on the mid south shore of Lake Chapala. This bitumen is linked to the lake bottom and when the water level decreases sufficiently it is possible to access these tar bodies as islands. Because of these manifestations the Mexican oil company (PEMEX) drilled an exploration well (2,348m) at Tizapan El Alto without success. Hydrothermal activity is evident in the tar island zone as three in-shore thermal springs (26.8 m depth, 48.5° C, pH 7.8 and oriented N-S). The preliminary analyses by GC-MS of the tar from these islands indicate hydrothermal petroleum derived from lake sedimentary organic matter, generated at low temperatures (150° -200° C). The tars contain no n-alkanes, no PAH or other aromatics, but a major UCM of branched and cyclic hydrocarbons and mature biomarkers derived from lacustrine biota. The biomarkers consist of mainly 17α (H),21β (H)-hopanes ranging from C27 to C34 (no C28), gammacerane, tricyclic terpanes (C20-C26), carotane and its cracking products, and drimanes (C14-C16). The biomarker composition indicates an organic matter source from bacteria and algae, typical of lacustrine ecosystems. 14C dating of samples from two tar islands yielded ages exceeding 40 kyrs, i.e., old carbon from hydrothermal/tectonic remobilization of bitumen from deeper horizons to the surface. The occurrence of hydrothermal petroleum in

Effectiveness of a refuge for Lake Trout in Western Lake Superior II: Simulation of future performance

USGS Publications Warehouse

Akins, Andrea L; Hansen, Michael J.; Seider, Michael J.

2015-01-01

Historically, Lake Superior supported one of the largest and most diverse Lake Trout Salvelinus namaycush fisheries in the Laurentian Great Lakes, but Lake Trout stocks collapsed due to excessive fishery exploitation and predation by Sea Lampreys Petromyzon marinus. Lake Trout stocking, Sea Lamprey control, and fishery regulations, including a refuge encompassing Gull Island Shoal (Apostle Islands region), were used to enable recovery of Lake Trout stocks that used this historically important spawning shoal. Our objective was to determine whether future sustainability of Lake Trout stocks will depend on the presence of the Gull Island Shoal Refuge. We constructed a stochastic age-structured simulation model to assess the effect of maintaining the refuge as a harvest management tool versus removing the refuge. In general, median abundances of age-4, age-4 and older (age-4+), and age-8+ fish collapsed at lower instantaneous fishing mortality rates (F) when the refuge was removed than when the refuge was maintained. With the refuge in place, the F that resulted in collapse depended on the rate of movement into and out of the refuge. Too many fish stayed in the refuge when movement was low (0–2%), and too many fish became vulnerable to fishing when movement was high (≥22%); thus, the refuge was more effective at intermediate rates of movement (10–11%). With the refuge in place, extinction did not occur at any simulated level of F, whereas refuge removal led to extinction at all combinations of commercial F and recreational F. Our results indicate that the Lake Trout population would be sustained by the refuge at all simulated F-values, whereas removal of the refuge would risk population collapse at much lower F (0.700–0.744). Therefore, the Gull Island Shoal Refuge is needed to sustain the Lake Trout population in eastern Wisconsin waters of Lake Superior.

The Biogeography of Endorheic Soda Lakes in the Western United States

NASA Astrophysics Data System (ADS)

Stamps, B. W.; Petryshyn, V.; Johnson, H.; Berelson, W.; Nunn, H. S.; Stevenson, B. S.; Loyd, S. J.; Oremland, R. S.; Miller, L. G.; Rosen, M. R.; Corsetti, F. A.; Spear, J. R.

2016-12-01

Closed-basin (endorheic) soda lakes are of economic, social, and ecological importance. Shifts in global climate, which in turn affects local climate, significantly impact the distribution and diversity of microbial communities and lake ecologies. In California, the Mono Lake Basin (MLB) is especially fragile, as it has undergone a significant decline in lake level beginning in the early twentieth century due to both climatic effects and water diversion. The result is a lake with elevated salinity (60-90 g/L) and pH (9.8). The diversion of MLB water has created a unique lake environment dominated by a single macroeukaryote (Artemia monica) in which primary production is controlled at all depths by the microalgae Picocystis sp. In order to better understand the microbial diversity and functional potential of Mono Lake during an on-going drought and climatic upheaval, a combined geochemical, metagenomic, and metatranscriptomic study was undertaken. Members of The International GeoBiology course sampled the water column at multiple depths in the summer of 2016, during a large bloom of Picocystis. A mud spring from a volcanic island (Paoha) near the center of the lake was also sampled. The spring was recently submerged and interacts intermittently with Mono Lake, which may allow for mixing of microbial communities as lake levels fluctuate. Surface sediment samples were also taken from 7 m water depth. Finally, via SSU rRNA gene sequence analyses, the microbial communities of nearby soda lakes were compared in an attempt to place the Mono Lake community in the context of the overall regional biodiversity of endorheic soda lakes. Overall the microbial communities at Mono Lake were distinct both in the bacterial community composition and the abundance of Picocystis from those found at other sampled soda lakes or the surrounding rivers and springs. Our results reveal diverse microbial ecosystems at multiple lakes potentially at risk to continued climate change.

Seasonal inorganic nitrogen release in alpine lakes on the Colorado western slope

USGS Publications Warehouse

Inyan, B.I.; Williams, M.W.; Tonnessen, K.; Turk, J.T.; Campbell, D.H.

1998-01-01

In the Rocky Mountains, the association of increases in acidic deposition with increased atmospheric loading of sulfate and direct changes in surface water chemistry has been well established. The importance, though, of increased nitrogen (N) deposition in the episodic acidification of alpine lakes and N saturation in alpine ecosystems is only beginning to be documented. In alpine areas of the Colorado Front Range, modest loadings of N in deposition have been associated with leakage of N to surface waters. On the Colorado western slope, however, no leakage of N to surface waters has been reported. A 1995 study that included early season under-ice water samples that were not available in earlier studies showed that there is, in fact, N leakage to surface waters in some western slope basins. Under-ice nitrate (NO3-) concentrations were as high as 10.5 ??q L-1, and only decreased to detection limits in September. Landscape type appears to be important in leakage of N to surface waters, which is associated with basins having steep slopes, thin soils, and large amounts of exposed bedrock. NO3- leakage compounds the existing sensitivity to episodic acidification from low acid neutralizing capacity (ANC), which is less than 40 ??eq L-1 in those basins.

Egg thiamine status of Lake Ontario salmonines 1995-2004 with emphasis on lake trout

USGS Publications Warehouse

Fitzsimons, J.D.; Williston, B.; Williston, G.; Brown, L.; El-Shaarawi, A.; Vandenbyllaardt, L.; Honeyfeld, D.; Tillitt, D.; Wolgamood, M.; Brown, S.B.

2007-01-01

Alewives (Alosa pseudoharengus), the major prey fish for Lake Ontario, contain thiaminase. They are associated with development of a thiamine deficiency in salmonines which greatly increases the potential for developing an early mortality syndrome (EMS). To assess the possible effects of thiamine deficiency on salmonine reproduction we measured egg thiamine concentrations for five species of Lake Ontario salmonines. From this we estimated the proportion of families susceptible to EMS based on whether they were below the ED20, the egg thiamine concentration associated with 20% mortality due to EMS. The ED20s were 1.52, 2.63, and 2.99 nmol/g egg for Chinook salmon (Oncorhynchus tshawytscha), lake trout (Salvelinus namaycush), and coho salmon (Oncorhynchus kisutch), respectively. Based on the proportion of fish having egg thiamine concentrations falling below the ED20, the risk of developing EMS in Lake Ontario was highest for lake trout, followed by coho (O. kisutch), and Chinook salmon, with the least risk for rainbow trout (O. mykiss). For lake trout from western Lake Ontario, mean egg thiamine concentration showed significant annual variability during 1994 to 2003, when the proportion of lake trout at risk of developing EMS based on ED20 ranged between 77 and 100%. Variation in the annual mean egg thiamine concentration for western Lake Ontario lake trout was positively related (p < 0.001, r2 = 0.94) with indices of annual adult alewife biomass. While suggesting the possible involvement of density-dependent changes in alewives, the changes are small relative to egg thiamine concentrations when alewife are not part of the diet and are of insufficient magnitude to allow for natural reproduction by lake trout.

Eco-Environment Status Evaluation and Change Analysis of Qinghai Based on National Geographic Conditions Census Data

NASA Astrophysics Data System (ADS)

Zheng, M.; Zhu, M.; Wang, Y.; Xu, C.; Yang, H.

2018-04-01

As the headstream of the Yellow River, the Yangtze River and the Lantsang River, located in the hinterland of Qinghai-Tibet Plateau, Qinghai province is hugely significant for ecosystem as well as for ecological security and sustainable development in China. With the accomplishment of the first national geographic condition census, the frequent monitoring has begun. The classification indicators of the census and monitoring data are highly correlated with Technical Criterion for Ecosystem Status Evaluation released by Ministry of Environmental Protection in 2015. Based on three years' geographic conditions data (2014-2016), Landsat-8 images and thematic data (water resource, pollution emissions, meteorological data, soil erosion, etc.), a multi-years and high-precision eco-environment status evaluation and spatiotemporal change analysis of Qinghai province has been researched on the basis of Technical Criterion for Ecosystem Status Evaluation in this paper. Unlike the evaluation implemented by environmental protection department, the evaluation unit in this paper is town rather than county. The evaluation result shows that the eco-environment status in Qinghai is generally in a fine condition, and has significant regional differences. The eco-environment status evaluation based on national geographic conditions census and monitoring data can improve both the time and space precision. The eco-environment status with high space precise and multi-indices is a key basis for environment protection decision-making.

Can pelagic forage fish and spawning cisco (Coregonus artedi) biomass in the western arm of Lake Superior be assessed with a single summer survey?

USGS Publications Warehouse

Yule, D.L.; Stockwell, J.D.; Schreiner, D.R.; Evrard, L.M.; Balge, M.; Hrabik, T.R.

2009-01-01

Management efforts to rehabilitate lake trout Salvelinus namaycush in Lake Superior have been successful and the recent increase in their numbers has led to interest in measuring biomass of pelagic prey fish species important to these predators. Lake Superior cisco Coregonus artedi currently support roe fisheries and determining the sustainability of these fisheries is an important management issue. We conducted acoustic and midwater trawl surveys of the western arm of Lake Superior during three periods: summer (July-August), October, and November 2006 to determine if a single survey can be timed to estimate biomass of both prey fish and spawning cisco. We evaluated our methods by comparing observed trawl catches of small (<250 mm total length) and large fish to expected trawl catches based on acoustic densities in the trawl path. We found the relationship between observed and expected catches approached unity over a wide range of densities, suggesting that our acoustic method provided reasonable estimates of fish density, and that midwater trawling methods were free of species- and size-selectivity issues. Rainbow smelt Osmerus mordax was by number the most common species captured in the nearshore (<80 m bathymetric depth) stratum during all three surveys, while kiyi Coregonus kiyi was predominant offshore except during November. Total biomass estimates of rainbow smelt in the western arm were similar during all three surveys, while total biomass of kiyi was similar between summer and October, but was lower in November. Total biomass of large cisco increased substantially in November, while small bloater Coregonus hoyi biomass was lower. We compared our summer 2006 estimates of total fish biomass to the results of a summer survey in 1997 and obtained similar results. We conclude that the temporal window for obtaining biomass estimates of pelagic prey species in the western arm of Lake Superior is wide (July through October), but estimating spawning cisco abundance

[Soil N/P ratio distribution characteristics of alpine grassland ecosystem in Qinghai-Tibet Plateau].

PubMed

Wang, Jian-Lin; Zhong, Zhi-Ming; Wang, Zhong-Hong; Chen, Bao-Xiong; Zhang, Xian-Zhou; Shen, Zhen-Xi; Hu, Xing-Xiang; Dacizhuoga

2013-12-01

The distribution characteristics of soil N/P ratio in alpine grassland ecosystem of Qinghai-Tibet Plateau were surveyed by field investigation and laboratory analysis. Horizontally, soil N/ P ratio was generally higher in west and lower in east in a manner of staggered patch distribution, with higher N/P ratios mainly centralized in the hinterland of northern part of Tibet Plateau and in the lake basin area of the northern foot of Himalayas. Significant differences in soil N/P ratio were observed among grassland types and natural transects. Vertically, the distribution of N/P ratio along the soil profile from aboveground to underground among different grass types could be categorized into five patterns, including low-high-low-high, low-high-low, low-high, high-low-high-low, and high-low-high. The N/P ratio showed a significant positive correlation with soil bulk density at 0-20 cm depth, soil water content at 20-30 cm depth, contents of soil available K and total nitrogen, respectively. However, it showed significant negative correlation with soil bulk density at 20-30 cm depth, contents of soil available P and total P, respectively.

First numerical ages from the northern lake Chapala shoreline, western Mexico, and their importance for palaeontology and archaeology

NASA Astrophysics Data System (ADS)

Kadereit, Annette; Dewitt, Regina; Terrazas, Alejandro; Stinnesbeck, Wolfgang; Zipf, Lars; Schukraft, Gerd

2017-04-01

Lake Chapala in the central-western Mexican state of Jalisco is the successor of the late-Miocene to early Pleistocene palaeo-lake Jalisco and is situated in an active neotectonic basin at approximately 1500 m above sea level. It presently covers an area of ca. 1100 km2 and represents Mexico's largest freshwater reservoir. As water depth reaches only a few meters the position of its shorelines has fluctuated substantially throughout the lake's history due to volcanic and tectonic activity as well as climate fluctuations. One of the more recently abandoned shorelines is preserved on the northern shoreline east of Ajijic at San Antonio Tlayacapan (SAT), where sand and silt deposits crop out at the present waterline. The beach sediments at SAT are famous for their fossils of late Wisconsian age (e.g. ground sloths, gomphotheriids), but also host human osteological remains, which are now housed in the Museo de Paleontología de Guadalajara, in the state capital. Numeric dating of sediments from Lake Chapala has proven to be exceedingly difficult as bones are heavily mineralized by Fe-Mn-oxides. In addition, input of ancient carbon exists from hydrothermal sources deep underneath the lake bottom and its distribution throughout the lake-water body, with currents driven by easterly winds and respective counter-currents, leading to age inversions for 14C-dating (Zárate-del-Valle et al. 2011). As 14C radiometric methods are thus shown to be problematic we here tested the possibility of optical stimulated luminescence (OSL) dating. Diverse tests showed that the samples were not adequate for coarse-grain quartz dating or post infrared stimulated (post-IR) blue-light stimulated (BLSL) dating of polymineral fine grains. The blue emission band of the infrared stimulated luminescence (IRSL) signal of the natural samples has been proven to be quite dim, so that a single aliquot regeneration (SAR) protocol (Murray & Wintle 2000) was not suitable. Finally, we applied a traditional

DETERMINING THE INFLUENCE OF LANDSCAPE AND RESEARCH-SPECIFIC HABITAT VARIABLES ON VARIATION OF THERMAL CHARACTERISTICS OF STREAMS WITHIN WESTERN LAKE SUPERIOR WATERSHEDS

EPA Science Inventory

As part of a study to develop and test a framework for predicting sensitivity of watersheds to land-use activities, temperatures were monitored in 48 second- and third- order streams on the north and south shores of western Lake Superior. Maximun 21-day average temperatures, whic...

[Analysis of vegetation spatial and temporal variations in Qinghai Province based on remote sensing].

PubMed

Wang, Li-wen; Wei, Ya-xing; Niu, Zheng

2008-06-01

1 km MODIS NDVI time series data combining with decision tree classification, supervised classification and unsupervised classification was used to classify land cover type of Qinghai Province into 14 classes. In our classification system, sparse grassland and sparse shrub were emphasized, and their spatial distribution locations were labeled. From digital elevation model (DEM) of Qinghai Province, five elevation belts were achieved, and we utilized geographic information system (GIS) software to analyze vegetation cover variation on different elevation belts. Our research result shows that vegetation cover in Qinghai Province has been improved in recent five years. Vegetation cover area increases from 370047 km2 in 2001 to 374576 km2 in 2006, and vegetation cover rate increases by 0.63%. Among five grade elevation belts, vegetation cover ratio of high mountain belt is the highest (67.92%). The area of middle density grassland in high mountain belt is the largest, of which area is 94 003 km2. Increased area of dense grassland in high mountain belt is the greatest (1280 km2). During five years, the biggest variation is the conversion from sparse grassland to middle density grassland in high mountain belt, of which area is 15931 km2.

Lake trout rehabilitation in Lake Ontario

USGS Publications Warehouse

Elrod, Joseph H.; O'Gorman, Robert; Schneider, Clifford P.; Eckert, Thomas H.; Schaner, Ted; Bowlby, James N.; Schleen, Larry P.

1995-01-01

Attempts to maintain the native lake trout (Salvelinus namaycush) population in Lake Ontario by stocking fry failed and the species was extirpated by the 1950s. Hatchery fish stocked in the 1960s did not live to maturity because of sea lamprey (Petromyzon marinus) predation and incidental commercial harvest. Suppression of sea lampreys began with larvicide treatments of Lake Ontario tributaries in 1971 and was enhanced when the tributaries of Oneida Lake and Lake Erie were treated in the 1980s. Annual stocking of hatchery fish was resumed with the 1972 year class and peaked at about 1.8 million yearlings and 0.3 million fingerlings from the 1985–1990 year classes. Survival of stocked yearlings declined over 50% in the 1980 s and was negatively correlated with the abundance of lake trout > 550 mm long (r = −0.91, P < 0.01, n = 12). A slot length limit imposed by the State of New York for the 1988 fishing season reduced angler harvest. Angler harvest in Canadian waters was 3 times higher in eastern Lake Ontario than in western Lake Ontario. For the 1977–1984 year classes, mean annual survival rate of lake trout age 6 and older was 0.45 (range: 0.35–0.56). In U.S. waters during 1985–1992, the total number of lake trout harvested by anglers was about 2.4 times greater than that killed by sea lampreys. The number of unmarked lake trout < 250 mm long in trawl catches in 1978–1992 was not different from that expected due to loss of marks and failure to apply marks at the hatchery, and suggested that recruitment of naturally-produced fish was nil. However, many of the obstacles which may have impeded lake trout rehabilitation in Lake Ontario during the 1980s are slowly being removed, and there are signs of a general ecosystem recovery. Significant recruitment of naturally produced lake trout by the year 2000, one interim objective of the rehabilitation plan for the Lake, may be achieved.

Environmental characteristics and changes of sediment pore water dissolved organic matter in four Chinese lakes.

PubMed

Mostofa, Khan M G; Li, Wen; Wu, Fengchang; Liu, Cong-Qiang; Liao, Haiqing; Zeng, Li; Xiao, Min

2018-01-01

Sediment pore waters were examined in four Chinese lakes (Bosten, Qinghai, Chenghai and Dianchi) to characterise the sources of dissolved organic matter (DOM) and their microbial changes in the sediment depth profiles. Parallel factor (PARAFAC) modelling on the sample fluorescence spectra confirmed that the pore water DOM was mostly composed of two components with a mixture of both allochthonous and autochthonous fulvic acid-like substances in three lakes, except Lake Dianchi, and protein-like components in Lake Bosten. However, DOM in Lake Dianchi was composed of three components, including a fulvic acid-like, and two unidentified components, which could originate from mixed sources of either sewerage-impacted allochthonous or autochthonous organic matter (OM). Dissolved organic carbon (DOC) concentrations were typically high (583-7410 μM C) and fluctuated and increased vertically in the depth profile. The fluorescence intensity of the fulvic acid-like substance and absorbance at 254 nm increased vertically in the sediment pore waters of three lakes. A significant relationship between DOC and the fluorescence intensity of the fulvic acid-like component in the sediment pore waters of three lakes, except Lake Dianchi, suggested that the fulvic acid-like component could significantly contribute to total DOM and could originate via complex microbial processes in early diagenesis on OM (ca. phytoplankton, terrestrial plant material) in these lakes. Pore water DOM components could therefore be a useful indicator to assess the DOM sources of the lake sediment during sedimentation over the past several decades, which have been heavily affected by ambient terrestrial vegetation and human activities.

Pyramid Lake Renewable Energy Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

John Jackson

2008-03-14

The Pyramid Lake Paiute Tribe is a federally recognized Tribe residing on the Pyramid Lake Reservation in western Nevada. The funding for this project was used to identify blind geothermal systems disconnected from geothermal sacred sites and develop a Tribal energy corporation for evaluating potential economic development for profit.

Water chemistry in the rives of the permafrost regions on the eastern Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wu, X.; Ma, X.; Ye, L.; Liu, G.

2017-12-01

Qinghai-Tibetan is the largest middle-low latitude permafrost areas on the world. There are several large rivers in the plateau, and the changes of the water resources of these rivers are associated with the water resource security of more than 1.35 billion people. Due to the high gradients, these rivers have a tremendous amount of potential energy for electricity output. To promote economic and social development and provide clean energy, hydropower development has taken place on several rivers which originate on the Qinghai-Tibetan Plateau. Since dam construction affect the flow velocity, water temperature, sediments delivery as well as organic matter and nitrogen, it is important to investigate the river chemistry in the head rivers of the reservoirs. We examined the water physio-chemical characteristics in the rivers under the typical vegetation types in the eastern Qinghai-Tibetan Plateau, and further analyzed their relationship to vegetation. The results showed that the total suspended sediment in the rivers were higher within the catchment of alpine steppe, with the lowest dissolved organic carbon content. In contrast, the rivers within the meadow had the highest dissolved organic carbon and lowest total suspension sediment. The dissolved organic carbon significantly positively correlated with the proportions of the meadow and wet meadow in the catchment. The pH, turbidity, and SUVA254 and dissolved organic carbon also correlated with each other. The results suggest that the vegetation type strongly affect the water chemistry in the permafrost regions on the Qinghai-Tibetan Plateau.

Unharvested fishes in the U. S. commercial fishery of western Lake Erie in 1969

USGS Publications Warehouse

Van Meter, Harry D.

1973-01-01

Potential commercial fish production was estimated for U.S. waters of western Lake Erie in 1969 from pounds landed and pounds discarded. Periodic observations of catches in haul seines and trap nets revealed that about 37% of the catch (by weight) in haul seines and 26% of that in trap nets were low-value fishes that were discarded. Projection of these discarded catches to include the total fishing effort indicated that an additional 2.8 million lb of low-value species would have been landed in 1969 if a reasonable profit had been assured. It is concluded that the sustained yield could be increased considerably with only a moderate increase in fishing effort.

The Qinghai-Tibetan plateau: how high do Tibetans live?

PubMed

Wu, T

2001-01-01

A lower incidence of chronic mountain sickness (CMS) has apparently been observed in Tibetans in comparison to Andeans of South America. In the past, the hypothesis of "geographic differences" has been constructed to explain these population differences. In order to assess the importance of this hypothesis in the development of CMS, this article will first review the geographic factors of the Qinghai-Tibetan plateau where Tibetans live. The plateau is bounded by the Himalayas in the southwest and the Kunlun and Aljin mountains in the northeast. It towers over southwestern China at an average elevation of 4000 m above sea level and is known as "the roof of the world." Covering more than 2.5 million km(2), the Qinghai-Tibetan plateau is the highest and largest plateau in the world. The plateau has a highland continental climate and a very complex topography with great variations. Second, at what altitude do Tibetans live? In 1990 it was estimated that 4,594,188 Tibetans live on the plateau, with 53% living at an altitude over 3500 m. Fairly large numbers (about 600,000) live at an altitude exceeding 4500 m in the Chantong-Qingnan area. People of Tibetan ethnic descent are lifelong high-altitude residents and cannot easily move to higher or lower elevations. Over 90% of the population are engaged in farming and herding. The upper altitude limit of crops is around 4500 m, while the nomads reside above 4800 m and 5500 m. Recently, mining activities in the plateau have sustained a part of the population that lives permanently at altitudes between 3700 and 6000 m. Therefore, the Tibetans living in the Qinghai-Tibetan plateau live at an altitude as high as the Andeans in South America. Thus the apparently low incidence of CMS in Tibetans cannot be ascribed to "geographic differences." We propose that the genetic adaptation to hypoxia that has occurred in Tibetans is of importance in CMS.

Cyclic heliothermal behaviour of the shallow, hypersaline Lake Hayward, Western Australia

NASA Astrophysics Data System (ADS)

Turner, Jeffrey V.; Rosen, Michael R.; Coshell, Lee; Woodbury, Robert J.

2018-05-01

Lake Hayward is one of only about 30 hypersaline lakes worldwide that is meromictic and heliothermal and as such behaves as a natural salt gradient solar pond. Lake Hayward acts as a local groundwater sink, resulting in seasonally variable hypersaline lake water with total dissolved solids (TDS) in the upper layer (mixolimnion) ranging between 56 kg m-3 and 207 kg m-3 and the deeper layer (monimolimnion) from 153 kg m-3 to 211 kg m-3. This is up to six times the salinity of seawater and thus has the highest salinity of all eleven lakes in the Yalgorup National Park lake system. A program of continuously recorded water temperature profiles has shown that salinity stratification initiated by direct rainfall onto the lake's surface and local runoff into the lake results in the onset of heliothermal conditions within hours of rainfall onset. The lake alternates between being fully mixed and becoming thermally and chemically stratified several times during the annual cycle, with the longest extended periods of heliothermal behaviour lasting 23 and 22 weeks in the winters of 1992 and 1993 respectively. The objective was to quantify the heat budgets of the cyclical heliothermal behaviour of Lake Hayward. During the period of temperature profile logging, the maximum recorded temperature of the monimolimnion was 42.6 °C at which time the temperature of the mixolimnion was 29.4 °C. The heat budget of two closed heliothermal cycles initiated by two rainfall events of 50 mm and 52 mm in 1993 were analysed. The cycles prevailed for 11 and 20 days respectively and the heat budget showed net heat accumulations of 34.2 MJ m-3 and 15.4 MJ m-3, respectively. The corresponding efficiencies of lake heat gain to incident solar energy were 0.17 and 0.18 respectively. Typically, artificial salinity gradient solar ponds (SGSP) have a solar radiation capture efficiencies ranging from 0.10 up to 0.30. Results from Lake Hayward have implications for comparative biogeochemistry and its

Species density of waterbirds in offshore habitats in western Lake Erie

USGS Publications Warehouse

Stapanian, M.A.; Waite, Thomas A.

2003-01-01

Offshore censuses of birds are lacking for inland seas, such as the Laurentian Great Lakes, but may provide valuable information for managing species that are in conflict with human interests. Birds were counted along 31 established transects in four habitats in western Lake Erie: offshore of waterbird refuges, offshore of beaches with human development, on reefs and shoals, and in open water. A total of 161 10-min counts were conducted between 24 April and 1 September 2000. The mean number of aquatic bird species/kmA? (species density) was greater offshore of refuges than on open water. For all habitats combined, species density increased over time. This was mainly due to the arrival of Bonaparte's Gulls (Larus philadelphia) and Great Black-backed Gulls (L. marinus), two fall and winter residents that do not breed in the study area, and increased use of open water and reefs and shoals by Herring Gulls (L argentatus) and Ring-billed Gulls (L delawarensis) after the nesting season. Species density was not strongly spatially autocorrelated, either for all species or for only those species that were floating on the water when recorded. Neither Double-crested Cormorants (Phalacrocorax auritus) nor Herring Gulls exhibited spatial autocorrelation. In contrast, Bonaparte's and Ring-billed gulls exhibited positive spatial autocorrelations. Unlike marine studies, species density was only weakly associated with water depth. This result was due mainly to Double-crested Cormorants, the only diving bird species that lived year-round in the area, which preferred reefs and shoals (depth 3-6 m) over open water (10 m). The results suggest that offshore habitat influences species density in this area during the breeding and immediate post-breeding seasons.

Recolonization and possible recovery of burrowing mayflies (Ephemeroptera: Ephemeridae: Hexagenia spp.) in Lake Erie of the Laurentian Great Lakes

USGS Publications Warehouse

Schloesser, Don W.; Krieger, Kenneth A.; Ciborowski, Jan J.H.; Corkum, Lynda D.

2000-01-01

Burrowing mayflies of the genus Hexagenia spp. were widely distributed (ca. 80% of sites) and abundant (ca. 160 nymphs/m2) in the western basin of Lake Erie of the Laurentian Great Lakes in 1929–1930, prior to a period of anoxia in the mid 1950s. Nymphs were absent or rare in the basin between 1961 and 1973–1975. In 1979–1991, nymphs were infrequently found (13–46% of sites) in low abundance (3–40 nymphs/m2) near shore (<7.5 km from shore), but were absent or rare offshore (0–7% of sites at 0–1 nymphs/m2). Increased abundance occurred offshore between 1991 (0% of sites) and 1993 (52% of sites at 7/m2). Annual sampling, beginning in 1995, indicates that nymphs increased in both nearshore and offshore waters. By 1997, nymphs were found throughout the lake (88% of sites) at a mean density 40-fold greater (392/m2) than that observed in 1993 (11/m2). In 1998, the distribution of nymphs remained the same as 1997 (88% of sites) but density declined 3-fold (392 to 134/m2). These data indicate that mayflies have recolonized sediments of western Lake Erie and that their abundance may be similar to levels observed before their disappearance in the mid 1950s. However, prior to the mid 1950s, densities were greater in offshore than nearshore waters, but between 1979 and 1998 greater densities occurred near shore than offshore. In addition, there were two areas in the 1990s where low densities consistently occurred. Therefore, recovery of nymphs in western Lake Erie may not have been complete in 1998. At present we do not know the cause for the sudden recolonization of nymphs in large portions of western Lake Erie. Undoubtedly, pollution-abatement programs contributed to improved conditions that would have ultimately led to mayfly recovery in the future. However, the explosive growth of the exotic zebra mussel, Dreissena polymorpha, undoubtedly diverted plankton foods to bottom substrates which could have increased the speed at which Hexagenia spp. nymphs

A Four Lake Latitudinal Comparison Along Coastal Southern to Central California: A Late-Holocene Perspective on the Western US Precipitation Dipole.

NASA Astrophysics Data System (ADS)

Kirby, M.; Nichols, K. E.; Ramezan, R.; Palermo, J. A.; Hiner, C.; Bonuso, N.; Patterson, W. P.; Silveira, E.

2016-12-01

One of the dominant hydroclimatic features of the western United States is the winter season precipitation dipole. The dipole is characterized by a N-S antiphased precipitation regime presently centered on 40° N latitude (Cayan et al., 1998; Dettinger et al., 1998; Wise, 2010). For example, the position of the dipole dictates where CA receives its winter precipitation; thus, it is critical to understand the dipole from a paleoperspective, which at present is poorly known. Here, we present four lake sites spanning 33°-36° N latitude along coastal CA. These sites include: Lake Elsinore, Crystal Lake, Zaca Lake, and Abbott Lake. All four of these sites are located south of the dipole's average historic (since 1950 AD) latitude. The predominant hydroclimatic indicator is similar for each basin (i.e., grain size); although, several other indicators are used for independent verification/assessment of the grain size interpretation. Notably, these lakes contain varied age control, which limits site-to-site correlation without consideration of age model dependence. Following a Bayesian framework, MCMC algorithms in conjuction with radiocarbon dating will be used to estimate timestamps of sediment deposits with a degree of statistical uncertainty. Samples from the posterior distribution will be used to correlate hydroclimatic features between sites. Included in this analysis are tree ring records from the region to assess the similarities and differences as recorded in annually resolved tree ring drought reconstructions and decadally resolved lake sediment hydroclimatic records. Finally, the four sites are assessed in the context of tropical and north Pacific SST forcing.

Lake Worth bottom sediments : A chronicle of water-quality changes in western Fort Worth, Texas, 1914-2001

USGS Publications Warehouse

Braun, Christopher L.; Harwell, Glenn R.

2004-01-01

In spring 2000, the Texas Department of Health issued a fish-consumption advisory for Lake Worth, Tex., because of elevated concentrations of polychlorinated biphenyls (PCBs) in fish (Texas Department of Health, 2000). In response to the advisory and in cooperation with the U.S. Air Force, the U.S. Geological Survey (USGS) collected 21 surficial samples and three deeper gravity core samples from the sediment deposited at the bottom of Lake Worth. The purpose of that study was to assess the spatial distribution and historical trends of selected hydrophobic contaminants, including PCBs, and to determine, to the extent possible, sources of selected metals and hydrophobic organic contaminants (HOCs) to Lake Worth. Hydrophobic (literally “water fearing”) contaminants tend to chemically adsorb to soils and sediments. Fifteen of the top 20 contaminants on the Agency for Toxic Substances and Disease Registry (2001) priority list of hazardous substances are hydrophobic. Chemical analysis of sediment cores is one method that can be used to determine trends in HOCs such as PCBs. As sediments accumulate in lakes and reservoirs, they generate a partial historical record of water quality. This fact sheet describes the collection of sediment cores, age-dating methods, and historical trends in PCBs in Lake Worth sediments. The fact sheet also describes the spatial distribution of PCBs in surficial sediments and concludes with objectives for the second phase of data collection and the approach that will be used to achieve these objectives. The USGS published a comprehensive report on the first phase of the study (Harwell and others, 2003). Lake Worth is a reservoir on the West Fork Trinity River on the western edge of Fort Worth in Tarrant County. In 1914, the City of Fort Worth completed the reservoir to serve as a municipal water supply. Lake Worth has a surface area of 13.2 square kilometers and a storage capacity of 47 million cubic meters. The drainage area to the

Holocene climate in the western Great Lakes national parks and lakeshores: Implications for future climate change

USGS Publications Warehouse

Davis, Margaret; Douglas, Christine; Cole, K.L.; Winkler, Marge; Flaknes, Robyn

2000-01-01

We reconstruct Holocene climate history (last 10,000 years) for each of the U.S. National Park Service units in the western Great Lakes region in order to evaluate their sensitivity to global warming. Annual precipitation, annual temperature, and July and January temperatures were reconstructed by comparing fossil pollen in lake sediment with pollen in surface samples, assuming that ancient climates were similar to modern climate near analogous surface samples. In the early Holocene, most of the parks experienced colder winters, warmer summers, and lower precipitation than today. An exception is Voyageurs National Park in northern Minnesota where, by 8000 years ago, January temperatures were higher than today. The combination of high mean annual temperature and lower precipitation at Voyageurs resulted in a dry period between 8000 and 5000 years ago, similar to the Prairie Period in regions to the south and west. A mid-Holocene warm-dry period also occurred at other northern and central parks but was much less strongly developed. In southern parks there was no clear evidence of a mid-Holocene warm-dry period. These differences suggest that global model predictions of a warm, dry climate in the northern Great Plains under doubled atmospheric CO2 may be more applicable to Voyageurs than to the other parks. The contrast in reconstructed temperatures at Voyageurs and Isle Royale indicates that the ameliorating effect of the Great Lakes on temperatures has been in effect throughout the Holocene and presumably will continue in the future, thus reducing the potential for species loss caused by future temperature extremes. Increased numbers of mesic trees at all of the parks in the late Holocene reflect increasing annual precipitation. This trend toward more mesic conditions began 6000 years ago in the south and 4000 years ago in the north and increased sharply in recent millennia at parks located today in lake-effect snow belts. This suggests that lake-effect snowfall is

Phosphorus and Defoliation Interact and Improve the Growth and Composition of the Plant Community and Soil Properties in an Alpine Pasture of Qinghai-Tibet Plateau.

PubMed

Qi, Juan; Nie, Zhongnan; Jiao, Ting; Zhang, Degang

2015-01-01

Pasture degradation caused by overgrazing and inappropriate fertiliser management is a major production and environmental threat in Qinghai-Tibet Plateau. Previous research has focused on the effects of mixed nitrogen (N) and phosphorus (P) fertiliser and reduced grazing pressure on the plant community of the grassland; however, the role of P and how it interacts with various defoliation (the process of the complete or partial removal of the above-ground parts of plants by grazing or cutting) intensities on the plant and soil of the grassland ecosystem have not been quantified. A field experiment was conducted to quantify how P application in combination of defoliation pressure could impact the dynamic change of the plant and soil in a native alpine grassland ecosystem of the Qinghai-Tibet Plateau, China, from May 2012 to September 2014. A split-plot design with 4 replicates and repeated measures was used to determine the growth and composition of plant community and soil physical and chemical properties under various levels of P fertiliser and defoliation intensity. The results showed that applying 20 kg P/ha increased the herbage yield of Melissitus ruthenica by 68% and total pasture yield by 25%. Close defoliation favoured the growth and plant frequency of the shorter species, whereas lax defoliation favoured that of the taller plant species. Medium P rate and cutting to 3 cm above ground gave an overall best outcome in pasture yield, quality and frequency and soil moisture and nutrient concentration. Application of P fertiliser with a moderate defoliation pressure to promote legume growth and N fixation has the potential to achieve multiple benefits in increasing pasture and livestock production and improving environmental sustainability in the alpine pasture of Qinghai-Tibet Plateau, a fragile and P-deficient ecosystem zone in China and its western neighbouring countries.

Phosphorus and Defoliation Interact and Improve the Growth and Composition of the Plant Community and Soil Properties in an Alpine Pasture of Qinghai-Tibet Plateau

PubMed Central

Qi, Juan; Nie, Zhongnan; Jiao, Ting; Zhang, Degang

2015-01-01

Pasture degradation caused by overgrazing and inappropriate fertiliser management is a major production and environmental threat in Qinghai-Tibet Plateau. Previous research has focused on the effects of mixed nitrogen (N) and phosphorus (P) fertiliser and reduced grazing pressure on the plant community of the grassland; however, the role of P and how it interacts with various defoliation (the process of the complete or partial removal of the above-ground parts of plants by grazing or cutting) intensities on the plant and soil of the grassland ecosystem have not been quantified. A field experiment was conducted to quantify how P application in combination of defoliation pressure could impact the dynamic change of the plant and soil in a native alpine grassland ecosystem of the Qinghai-Tibet Plateau, China, from May 2012 to September 2014. A split-plot design with 4 replicates and repeated measures was used to determine the growth and composition of plant community and soil physical and chemical properties under various levels of P fertiliser and defoliation intensity. The results showed that applying 20 kg P/ha increased the herbage yield of Melissitus ruthenica by 68% and total pasture yield by 25%. Close defoliation favoured the growth and plant frequency of the shorter species, whereas lax defoliation favoured that of the taller plant species. Medium P rate and cutting to 3 cm above ground gave an overall best outcome in pasture yield, quality and frequency and soil moisture and nutrient concentration. Application of P fertiliser with a moderate defoliation pressure to promote legume growth and N fixation has the potential to achieve multiple benefits in increasing pasture and livestock production and improving environmental sustainability in the alpine pasture of Qinghai-Tibet Plateau, a fragile and P-deficient ecosystem zone in China and its western neighbouring countries. PMID:26513363

Walleye in Lake Erie and Lake St. Clair

USGS Publications Warehouse

Nepszy, S.J.; Davies, D.H.; Einhouse, D.; Hatch, R.W.; Isbell, G.; MacLennan, D.; Muth, K.M.

1991-01-01

The history and current status of walleye (Stizostedion vitreum vitreum) stocks in Lake Erie and Lake St. Clair are reviewed in relation to their exploitation by commercial and recreational fishermen, environmental factors, rehabilitation efforts, and community dynamics. Management initiatives and stock recovery under these processes are outlined. After the collapse of the fishery in 1957, the highly productive walleye stock of western Lake Erie remained depressed through the 1960s, while the eastern basin stock remained stable. Closure of the fishery for walleye from 1970-73 because of mercury contamination provided an opportunity for the development of an international interagency management plan. With quota management, the walleye stock in western Lake Erie responded well to limited exploitation, steadily increased, and expanded its range. As population expanded, growth began to decline and was more apparent in the young-of-the-year (YOY) in the 1970s, and in older walleye in the late 1970s and 1980s. At the turn of the century, commercial harvest of walleye in Lake St. Clair ranged from 12-127 tonnes annually. A relatively stable period from 1910-59 was followed by significantly increased harvests (100-150 t) in 1959-65. This increase was a result of increased commercial exploitation as well as an increased abundance of walleye. After the mercury contamination problem of 1970, angling effort and harvest was reduced but then gradually increased in Ontario waters from 37 t in 1973 to 62 t in 1988. The increased mean age of the stock during the early 1970s was due to a few strong year-classes (1970, 1972, and 1974) as well as a period of stable or reduced catch per unit effort. With the current mean age not reduced significantly, the stocks of walleye should continue to provide good yields.

[Mutation analysis of the PAH gene in children with phenylketonuria from the Qinghai area of China].

PubMed

He, Jiang; Wang, Hui-Zhen; Xu, Fa-Liang; Yang, Xi; Wang, Rui; Zou, Hong-Yun; Yu, Wu-Zhong

2015-11-01

To study the mutation characteristics of the phenylalanine hydroxylase (PAH) gene in children with phenylketonuria (PKU) from the Qinghai area of China, in order to provide basic information for genetic counseling and prenatal diagnosis. Mutations of the PAH gene were detected in the promoter and exons 1-13 and their flanking intronic sequences of PAH gene by PCR and DNA sequencing in 49 children with PKU and their parents from the Qinghai area of China. A total of 30 different mutations were detected in 80 out of 98 mutant alleles (82%), including 19 missense (63%), 5 nonsense (17%), 3 splice-site (10%) and 3 deletions (10%). Most mutations were detected in exons 3, 6, 7, 11 and intron 4 of PAH gene. The most frequent mutations were p.R243Q (19%), IVS4-1G>A (9%), p.Y356X (7%) and p.EX6-96A>G(5%). Two novel mutations p.N93fsX5 (c.279-282delCATC) and p.G171E (c.512G>A) were found. p.H64fsX9(c.190delC) was documented for the second time in Chinese PAH gene. The mutation spectrum of the gene PAH in the Qinghai population was similar to that in other populations in North China while significantly different from that in the populations from some provinces in southern China, Japan and Europe. The mutations of PAH gene in the Qinghai area of China demonstrate a unique diversity, complexity and specificity.

Potential strategies for recovery of lake whitefish and lake herring stocks in eastern Lake Erie

USGS Publications Warehouse

Oldenburg, K.; Stapanian, M.A.; Ryan, P.A.; Holm, E.

2007-01-01

Lake Erie sustained large populations of ciscoes (Salmonidae: Coregoninae) 120 years ago. By the end of the 19th century, abundance of lake whitefish (Coregonus clupeaformis) had declined drastically. By 1925, the lake herring (a cisco) population (Coregonus artedii) had collapsed, although a limited lake herring fishery persisted in the eastern basin until the 1950s. In the latter part of the 20th century, the composition of the fish community changed as oligotrophication proceeded. Since 1984, a limited recovery of lake whitefish has occurred, however no recovery was evident for lake herring. Current ecological conditions in Lake Erie probably will not inhibit recovery of the coregonine species. Recovery of walleye (Sander vitreus) and efforts to rehabilitate the native lake trout (Salvelinus namaycush) in Lake Erie will probably assist recovery because these piscivores reduce populations of alewife (Alosa psuedoharengus) and rainbow smelt (Osmerus mordax), which inhibit reproductive success of coregonines. Although there are considerable spawning substrates available to coregonine species in eastern Lake Erie, eggs and fry would probably be displaced by storm surge from most shoals. Site selection for stocking or seeding of eggs should consider the reproductive life cycle of the stocked fish and suitable protection from storm events. Two potential sites in the eastern basin have been identified. Recommended management procedures, including commercial fisheries, are suggested to assist in recovery. Stocking in the eastern basin of Lake Erie is recommended for both species, as conditions are adequate and the native spawning population in the eastern basin is low. For lake herring, consideration should be given to match ecophenotypes as much as possible. Egg seeding is recommended. Egg seeding of lake whitefish should be considered initially, with fingerling or yearling stocking suggested if unsuccessful. Spawning stocks of whitefish in the western basin of Lake

Cyclic heliothermal behaviour of the shallow, hypersaline Lake Hayward, Western Australia

USGS Publications Warehouse

Turner, Jeffrey V.; Rosen, Michael R.; Coshell, Lee; Woodbury, Robert J.

2018-01-01

Lake Hayward is one of only about 30 hypersaline lakes worldwide that is meromictic and heliothermal and as such behaves as a natural salt gradient solar pond. Lake Hayward acts as a local groundwater sink, resulting in seasonally variable hypersaline lake water with total dissolved solids (TDS) in the upper layer (mixolimnion) ranging between 56 kg m−3 and 207 kg m−3 and the deeper layer (monimolimnion) from 153 kg m−3 to 211 kg m−3. This is up to six times the salinity of seawater and thus has the highest salinity of all eleven lakes in the Yalgorup National Park lake system. A program of continuously recorded water temperature profiles has shown that salinity stratification initiated by direct rainfall onto the lake’s surface and local runoff into the lake results in the onset of heliothermal conditions within hours of rainfall onset.The lake alternates between being fully mixed and becoming thermally and chemically stratified several times during the annual cycle, with the longest extended periods of heliothermal behaviour lasting 23 and 22 weeks in the winters of 1992 and 1993 respectively. The objective was to quantify the heat budgets of the cyclical heliothermal behaviour of Lake Hayward.During the period of temperature profile logging, the maximum recorded temperature of the monimolimnion was 42.6 °C at which time the temperature of the mixolimnion was 29.4 °C.The heat budget of two closed heliothermal cycles initiated by two rainfall events of 50 mm and 52 mm in 1993 were analysed. The cycles prevailed for 11 and 20 days respectively and the heat budget showed net heat accumulations of 34.2 MJ m−3 and 15.4 MJ m−3, respectively. The corresponding efficiencies of lake heat gain to incident solar energy were 0.17 and 0.18 respectively. Typically, artificial salinity gradient solar ponds (SGSP) have a solar radiation capture efficiencies ranging from 0.10 up to 0.30. Results from Lake Hayward have

An evaluation of ERTS data for oceanographic uses through Great Lakes studies

NASA Technical Reports Server (NTRS)

Strong, A. E. (Principal Investigator); Stumpf, H. G.

1974-01-01

The author has identified the following significant results. Prevailing wind direction on Lake Michigan is southwesterly, although during winter northwesterly stresses are common. Along the western shore the current favors a northward direction. ERTS-1 observations indicate that the southward-flowing current along the Michigan shoreline of the thumb is only reversed by southerly resultant wind stress. Along the Canadian shoreline, a northward current was observed north of Kettle Point. ERTS-1 data also reveal that a preferred southward-flowing current is found along the Detroit shoreline of Lake St. Clair. Eastward flow of surface water from the shallow western basin of Lake Erie into the middle basin is most obvious during northwesterly and northerly wind stresses. The reverse wind direction especially east and southeasterly, appear to hold the effluents from the Detroit and Maumee Rivers in the western basin. Across-lake winds from the north and south induce eddy-like circulation in surface waters of Lake Ontario. Counterclockwise alongshore flow persists in the western basin under most wind conditions.

Great Lakes

NASA Image and Video Library

2017-12-08

Bands of lake effect snow drift eastward from the western Great Lakes in this true-color image captured by the NOAA/NASA Suomi NPP satellite's Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on January 5, 2017. National Weather Service forecasters expect light to moderate lake effect snow showers to continue throughout the day today and into Saturday (1/7). Lake-effect snow forms when cold air passes over the warmer waters of a lake. This causes some lake water to evaporate into the air and warm it. This warmer, wetter air rises and cools as it moves away from the lake. When it cools, it releases that moisture and, if it’s cold enough, that moisture turns into snow. Although true-color images like this may appear to be photographs of Earth, they aren't. They are created by combining data from the three color channels on the VIIRS instrument sensitive to the red, green and blue (or RGB) wavelengths of light into one composite image. In addition, data from several other channels are often also included to cancel out or correct atmospheric interference that may blur parts of the image. Credit: NOAA/NASA/Suomi NPP via NOAA's Environmental Visualization Laboratory

Analysis on development situation and tendency of international Qinghai-Tibet Plateau studies

NASA Astrophysics Data System (ADS)

Wang, X.

2015-12-01

Qinghai-Tibet Plateau is one of the hotspots of the international earth science studies. The relative research papers have proliferated especially since 21st century. By using the the latest bibliometric indicators, the statistical analysis of the quantities and qualities was carried out for the Qinghai-Tibet Plateau literature indexed by SCIE during 1900 and 2012. It focused on the published years, journals, countries, cities, research institutes, international cooperation, and subjects. Some statistical results were displayed and deeply analyzed by using the tools of mapping knowledge domain (MKD) and geographic information system (GIS). The results of the Bibliometric analysis indicate that the publication and citation of QTP researches have a jump after entering the 21st century. China, USA, India, Canada and France are the main coutries engaged in the Qinghai-Tibet Plateau studies. Knowledge mapping results show that USA, UK and France have longer academic influential power of QTP researches, which indicates that these countries begin to study QTP early and the papers have longer permanent impacts. On the other hand, China, India and Japan have higher academic influential power in recent years, which indicate that these countries have more publications and higher impacts recently. The disciplines of QTP researches mainly focus on the geology, geochemistry &geophysics, environmental sciences &ecology, and so on. The spatial analysis indicates that the differences of the disciplines are emphasized by different countries. The above analysis results is hoped to integrate the new knowledge and reveal the development tendency of the QTP researches.

Vegetation and climate history in arid western China during MIS2: New insights from pollen and grain-size data of the Balikun Lake, eastern Tien Shan

NASA Astrophysics Data System (ADS)

Zhao, Yongtao; An, Cheng-Bang; Mao, Limi; Zhao, Jiaju; Tang, Lingyu; Zhou, Aifeng; Li, Hu; Dong, Weimiao; Duan, Futao; Chen, Fahu

2015-10-01

Marine Isotope Stage (MIS) 2 is mostly a cold period encompassing the Last Glacial Maximum (LGM), but the regional expression of MIS2 in arid areas of China is not well known. In this paper, we use high-resolution lacustrine pollen and grain-size records from Balikun Lake to infer vegetation, lake evolution, and climate in arid western China during MIS2. Our results suggest that: 1) the regional vegetation around Balikun was mainly dominated by desert and/or desert-steppe, and Balikun Lake was relatively shallow and experienced high aeolian input during MIS2; 2) distinctive runoff from mountain glacial meltwater in the eastern parts of the Balikun basin caused a high relative abundance of Artemisia pollen during the LGM (26.5-19.2 cal kyr BP), while simultaneously the desert areas expanded as indicated by the high abundance of desert shrubs (e.g., Elaeagnaceae, Rhamnaceae, Hippophae). This cold and dry LGM climate triggered a substantial lowering of lake level; 3) an extremely cold and dry climate prevailing from 17.0 to 15.2 cal kyr BP, correlated with Heinrich event 1 (H1), would explain the low vegetation cover found then; and 4) the warm and humid Bølling/Allerød interstadial (BA: ca. 15-ca. 13 cal kyr BP) is clearly recorded in the Balikun region by the development of wetland herb communities (e.g., Poaceae, Cyperaceae, Typha), and the lake level rose due to increased runoff. Our results challenge the traditional view of cold and wet climatic conditions and high lake levels in arid western China during the LGM, and we propose that changes in local temperature modulated by July insolation was an indispensable factor in triggering vegetation evolution in the Balikun region during MIS2.

Lake Mead and Drought

NASA Image and Video Library

2015-07-20

Lake Mead supplies water for Arizona, California, Mexico, and other western states. On June 23, the water level fell to 1075 feet, a record low. In 2000, for comparison, the water level was at 1214 feet. A 15-year drought and increased demands for water are to blame for the critical status of the water supply. The difference in 15 years is seen in this pair of images of the western part of Lake Mead, acquired June 21, 2000 by Landsat 7, and June 21, 2015 by ASTER. The images cover an area of 22.5 x 28.5 km, and are located at 36.1 degrees north, 114.7 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA19731

[Community structure and diversity of culturable moderate halophilic bacteria isolated from Qrhan salt lake on Qinghai-Tibet Plateau].

PubMed

Shen, Shuo

2017-04-04

I studied the community structure and diversity of culturable moderate halophilic bacteria isolated from Qrhan Salt Lake. I isolated and cultured the moderate halophilic bacteria on different selective media. After the 16S rRNA gene sequences was amplified and measured, I constructed the phylogenic tree, analyzed the community structure and calculated the diversity indexes according to the 16S rRNA gene information. A total of 421 moderate halophilic bacteria were isolated from water and mud samples in Qrhan Salt Lake. The 16S rRNA gene information showed that 4 potential novel species belonged to the family Bacillaceae. Eighty-three model strains belonged to 3 phylurms 6 families 16 genus. Among them, Bacillus sp., Oceanobacillus sp. and Halomonas sp. were dominant species. Diversity analysis showed that the diversity of strains isolated from water sample was higher than that from mud sample, but the dominance degree of strains isolated from mud sample was higher than that from water sample. The genetic diversity of moderate halophilic bacteria isolated from Qrhan Salt Lake was abundant. Also, there were dominant and novel species of culturable moderate halophilic bacteria in this lake.

Larval dispersal underlies demographically important inter-system connectivity in a Great Lakes yellow perch (Perca flavescens) population

USGS Publications Warehouse

Brodnik, Reed M.; Fraker, Michael E.; Anderson, Eric J.; Carreon-Martinez, Lucia; DeVanna, Kristen M.; Heath, Dan D.; Reichert, Julie M.; Roseman, Edward F.; Ludsin, Stuart A.

2016-01-01

Ability to quantify connectivity among spawning subpopulations and their relative contribution of recruits to the broader population is a critical fisheries management need. By combining microsatellite and age information from larval yellow perch (Perca flavescens) collected in the Lake St. Clair – Detroit River system (SC-DRS) and western Lake Erie with a hydrodynamic backtracking approach, we quantified subpopulation structure, connectivity, and contributions of recruits to the juvenile stage in western Lake Erie during 2006-2007. After finding weak (yet stable) genetic structure between the SC-DRS and two western Lake Erie subpopulations, microsatellites also revealed measurable recruitment of SC-DRS larvae to the juvenile stage in western Lake Erie (17-21% during 2006-2007). Consideration of pre-collection larval dispersal trajectories, using hydrodynamic backtracking, increased estimated contributions to 65% in 2006 and 57% in 2007. Our findings highlight the value of complementing subpopulation discrimination methods with hydrodynamic predictions of larval dispersal by revealing the SC-DRS as a source of recruits to western Lake Erie and also showing that connectivity through larval dispersal can affect the structure and dynamics of large-lake fish populations.

Carbon and hydrogen isotopic characterization of methane from wetlands and lakes of the Yukon-Kuskokwim Delta, Western Alaska

NASA Technical Reports Server (NTRS)

Martens, Christopher S.; Kelley, Cheryl A.; Chanton, Jeffrey P.; Showers, William J.

1992-01-01

The results are reported of a study of the carbon and hydrogen isotopic composition of methane from tundra environments of the Yukon-Kuskokwin Delta of western Alaska. The delta C-13 value of diffusive methane emissions from wet meadow tundra of the Delta is -65.82 +/- 2.21 per mil (n=18). Detritus-rich sediments of tundra lakes are loaded with methane-rich gas bubbles during the warm season. Spatial trend is the major gas concentration and isotopic values of methane in these gas bubbles appear to reflect processes associated with production rate and mechanisms; high methane concentrations, lightest delta C-13 values, the heaviest delta D value occur in detritus-rich sediments isolated from emergent vegetation. Heavier delta C-13 and lighter delta D values in methane from heavily vegetated lake margins suggest a shift toward a larger role for acetate fermentation in association with aquatic plants and plant detritus. Bubble ebullition is estimated to account for up to 17 percent of total Delta methane emissions.

Water-quality assessment of the western Lake Michigan drainages; analysis of available information on nutrients and suspended sediment, water years 1971-90

USGS Publications Warehouse

Robertson, Dale M.; Saad, D.A.

1996-01-01

To fulfill the goals of the NAWQA program, the USGS plans to examine 60 areas (study units) across the United States during full implementation of the program. In 1991, the NAWQA program went into full implementation with the intensive investigation of 20 of these study units; one of these study units is the Western Lake Michigan Drainages (WMIC) study unit.

Lake surface area variation and its responses to climatic change in Yamzhog Yumco Basin, South Tibet during 1970-2010

NASA Astrophysics Data System (ADS)

Zhang, X.; Tian, Y.; Sun, R.

2015-12-01

The research on lake extraction from multi-source and multi-temporal satellite images and the lake size variation can provide reliable method and indispensable information to deepen the understanding about alpine lake changes with the accelerating warming. With field survey experience in the Yamzhog Yumco Basin, South Tibet, the outlines of five lakes (i.e., Yamzhog Yumco, Chen Co, Kongmu Co, Bajiu Co and Puma Yumco) were delineated by the adoption of 42 scenes of satellite images from Landsat, CBERS and HJ from 1970 to 2010, basing on which the responses of alpine lakes to climate change at different timescales were explored. The results are summarized as follows. (1) The seasonal fluctuation of lake surface area was similar with different trend for the five alpine lakes. As for the last 41 years, the annual variation of lake surface area exhibited two kinds of patterns for the five alpine lakes. And the Yamzhog Yumco declined by 9.41%, while the rest four lakes expanded. (2) The responses of alpine lakes to climate change rely on different timescale and water replenishment types. On the one hand, the precipitation change was the predominant driving forces for the seasonal fluctuation and variation trend of lake size, and the rising temperature accounted for the inter-annual lake surface variation. On the other hand, the two kinds of alpine lakes behaviors were well correspondent with the warming temperature over the Qinghai-Tibetan Plateau. The lakes supplied mainly by precipitation shrunk as a result of increased evaporation, and lakes supplied mainly by glacier and snow meltwater, however, expanded because of the remarkable glacier recession. (3) The quantification of hydrological components would hopefully be improved, according to uncertainties analysis, with the adoption of microwave satellite images and higher resolution ones to disclose the interaction mechanism among climate, glacier, and lake in alpine regions.

Discrimination among spawning concentrations of Lake Superior lake herring based on trace element profiles in sagittae

USGS Publications Warehouse

Bronte, Charles R.; Hesselberg, Robert J.; Shoesmith, John A.; Hoff, Michael H.

1996-01-01

Little is known about the stock structure of lake herring Coregonus artedi in Lake Superior, and recent increases in harvestable stock sizes has led to expanded exploitation in some areas. Research on marine teleosts has demonstrated that chemical differences in sagittal otoliths can be used for identification of fish stocks. We used plasma emission spectrophotometry to measure the concentrations of 10 trace elements in the sagittal otoliths from lake herring captured at eight spawning sites in Lake Superior and from Little Star Lake, an inland lake outside the Lake Superior basin. Discriminant function analysis indicated that elemental concentrations provided site-specific information but that considerable overlap existed among some locations, especially those in western Lake Superior. Correct classification rates varied from 12.0% to 86.1% and were generally higher for spawning locations from embayments in eastern Lake Superior and for the outgroup population from Little Star Lake. The results presented here demonstrate the potential usefulness of this technique for strictly freshwater species, especially those that live in highly oligotrophic waters such as Lake Superior.

Lake-level variation in the Lahontan basin for the past 50,000 years

USGS Publications Warehouse

Benson, L.V.; Thompson, R.S.

1987-01-01

Selected radiocarbon data on surficial materials from the Lahontan basin, Nevada and California, provide a chronology of lake-level variation for the past 50,000 yr. A moderate-sized lake connected three western Lahontan subbasins (the Smoke Creek-Black Rock Desert subbasin, the Pyramid Lake subbasin, and the Winnemucca Dry Lake subbasin) from about 45,000 to 16,500 yr B.P. Between 50,000 and 45,000 yr B.P., Walker Lake rose to its sill level in Adrian Valley and spilled to the Carson Desert subbasin. By 20,000 yr B.P., lake level in the western Lahontan subbasins had risen to about 1265 m above sea level, where it remained for 3500 yr. By 16,000 yr B.P., lake level in the western Lahontan subbasins had fallen to 1240 m. This recession appears synchronous with a desiccation of Walker Lake; however, whether the Walker Lake desiccation resulted from climate change or from diversion of the Walker River is not known. From about 15,000 to 13,500 yr B.P., lake level rapidly rose, so that Lake Lahontan was a single body of water by 14,000 yr B.P. The lake appears to have reached a maximum highstand altitude of 1330 m by 13,500 yr B.P., a condition that persisted until about 12,500 yr B.P., at which time lake level fell ???100 m. No data exist that indicate the level of lakes in the various subbasins between 12,000 and 10,000 yr B.P. During the Holocene, the Lahontan basin was the site of shallow lakes, with many subbasins being the site of one or more periods of desiccation. The shape of the lake-level curve for the three western subbasins indicates that past changes in the hydrologic balance (and hence climate) of the Lahontan basin were large in magnitude and took place in a rapid step-like manner. The rapid changes in lake level are hypothesized to have resulted from changes in the mean position of the jet stream, as it was forced north or south by the changing size and shape of the continental ice sheet. ?? 1987.

Mladotice Lake, Czechia: The unique genesis and evolution of the lake basin

NASA Astrophysics Data System (ADS)

Janský, Bohumír; Šobr, Miroslav; Kliment, Zdeněk; Chalupová, Dagmar

2016-04-01

The Mladotice Lake is a lake of unique genetic type in Czechia. In May 1872 a landslide as a result an extreme rainfall event occurred in western Czechia, blocking the Mladoticky stream valley and creating the Mladotice Lake. The 1952 and 1975 air images document that collective farming had a great impact on the lake basin evolution when balks and field terraces were removed and fields were made much larger. Because of this change in land use we expected higher soil erosion and a related increase in the sedimentation rate. First bathymetric measurements of the newly created lake were carried out in 1972 and were repeated in 1999, in 2003 and in 2014. Our analysis of the sedimentary record aims to identify the sediment stratigraphy, its basic physical and chemical properties, isotope content and thin sections yield a detailed temporal resolution of the sedimentation chronology. In some areas a sediment thickness of 4 m was detected. Hence, the average sedimentation rate is from 2.2 to 2.7 cm per year. KEY WORDS: Mladotice Lake - extreme rainfall event - landslide - land use changes - flood events - bathymetric measurements - sedimentation dynamics - stratigraphy and geochemistry of lake sediments - analyses of isotopes - sedimentation rates.

Distribution and Fate of Black Carbon Nanoparticles from Regional Urban Pollution and Wildfire at a Large Subalpine Lake in the Western United States

NASA Astrophysics Data System (ADS)

Bisiaux, M. M.; Heyvaert, A. C.; Edwards, R.

2012-04-01

Emitted to the atmosphere through fire and fossil fuel combustion, refractory black carbon nanoparticles (rBC) impact human health, climate, atmospheric chemistry, and the carbon cycle. Eventually these particles enter aquatic environments, where their distribution, fate and association with other pollutants are still poorly characterized. This study presents results from an evaluation of rBC in the waters of oligotrophic Lake Tahoe and its watershed in the western United States. The study period included a large wildfire within the Tahoe basin, seasonal snowmelt, and a number of storm events that resulted in pulsed urban runoff into the lake with rBC concentrations up to four orders of magnitude higher than mid-lake concentrations. The results show that elevated rBC concentrations from wildfire and urban runoff were rapidly attenuated in the lake, suggesting unexpected aggregation or degradation of the particles that prevent rBC concentrations from building up in the water of this lake, renowned for its clarity. The rBC concentrations were also measured in sediment cores from Lake Tahoe to evaluate the sediment archive as a potential combustion record. The evidence suggests that rBC is efficiently transferred to these sediments, which preserve a local-to-regional scale history of rBC emissions, as revealed by comparison with other pollutant records in the sediment. Rapid removal of rBC soon after entry into the lake has implications for transport of rBC in the global aquatic environment and flux of rBC from continents to the global ocean.

Lake Ontario Shore Protection Study: Literature Review Report.

DTIC Science & Technology

1979-07-01

Rochester Region - Extracted from IJC, May 1976 31 Recreational Facilities and Lake Ontario State Parkway Expressways - Existing and Proposed...Throughout Areas of the Lake Ontario Western and Central Basins and the Genesee and Oswego River Basins - Extracted from the Genesee/Finger Lakes Regional...Planning Board, Nov. 1972 32 Recreational Facilities of the Rochester to St. Lawrence Region - Extracted from IJC, May 1976 33 Aquatic Vegetation

Snow effects on alpine vegetation in the Qinghai-Tibetan Plateau

USGS Publications Warehouse

Wang, Kun; Zhang, Li; Qiu, Yubao; Ji, Lei; Tian, Feng; Wang, Cuizhen; Wang, Zhiyong

2013-01-01

Understanding the relationships between snow and vegetation is important for interpretation of the responses of alpine ecosystems to climate changes. The Qinghai-Tibetan Plateau is regarded as an ideal area due to its undisturbed features with low population and relatively high snow cover. We used 500 m Moderate Resolution Imaging Spectroradiometer (MODIS) datasets during 2001–2010 to examine the snow–vegetation relationships, specifically, (1) the influence of snow melting date on vegetation green-up date and (2) the effects of snow cover duration on vegetation greenness. The results showed that the alpine vegetation responded strongly to snow phenology (i.e., snow melting date and snow cover duration) over large areas of the Qinghai-Tibetan Plateau. Snow melting date and vegetation green-up date were significantly correlated (p < 0.1) in 39.9% of meadow areas (accounting for 26.2% of vegetated areas) and 36.7% of steppe areas (28.1% of vegetated areas). Vegetation growth was influenced by different seasonal snow cover durations (SCDs) in different regions. Generally, the December–February and March–May SCDs played a significantly role in vegetation growth, both positively and negatively, depending on different water source regions. Snow's positive impact on vegetation was larger than the negative impact.

Evaluation of the Township Proper Carrying Capacity over Qinghai-Tibet plateau by CASA model

NASA Astrophysics Data System (ADS)

Wu, Chengyong; Cao, Guangchao; Xue, Huaju; Jiang, Gang; Wang, Qi; Yuan, Jie; Chen, Kelong

2018-01-01

The existing study of proper carrying capacity (PCC) has mostly focused on province or county administrative units, which can only macroscopically master the quantitative characteristics of PCC, but could not effectively take some animal husbandry management measures that are pertinent and operational. At town-scale, this paper used CASA model to estimate the PCC in Mongolian Autonomous County of Henan, Qinghai province, China,with serious grassland degeneration that mainly caused by overgrazing. The results showed that the PCC throughout the County was 950,417 sheep unit. For the township, the PCC of Saierlong and Duosong were the largest (247,100 sheep unit) and the smallest (82,016 sheep unit) respectively. This study will provide reference data for developing sustainable development of town-scale pasture policies and also will help to evaluate the health status of the alpine grassland ecosystem on Qinghai-Tibet plateau.

Predicting the locations of naturally fishless lakes

USGS Publications Warehouse

Schilling, Emily Gaenzle; Loftin, C.S.; Degoosh, K.E.; Huryn, Alexander D.; Webster, K.E.

2008-01-01

1. Fish have been introduced into many previously fishless lakes throughout North America over the past 100+ years. It is difficult to determine the historical distribution of fishless lakes, however, because these introductions have not always been well-documented. 2. Due to its glacial history and low human population density, the state of Maine (U.S.A.) may host the greatest number of naturally fishless lakes in the northeastern United States. However, less than one-quarter of Maine's 6000+ lakes have been surveyed for fish presence, and no accurate assessments of either the historical or current abundance and distribution of fishless lakes exist. 3. We developed methods to assess the abundance and distribution of Maine's naturally fishless lakes (0.6-10.1 ha). We hypothesized that the historical distribution of fishless lakes across a landscape is controlled by geomorphic and geographic conditions. 4. We used ArcGIS to identify landscape-scale geomorphic and geographic factors (e.g. connectivity, surrounding slope) correlated with fish absence in two geomorphic regions of Maine - the western and interior mountains and the eastern lowlands and foothills. By using readily available geographic information systems data our method was not limited to field-visited sites. We estimated the likelihood that a particular lake is fishless with a stepwise logistic regression model developed for each region. 5. The absence of fish from western lakes is related to altitude (+), minimum percent slope in the 500 m buffer (+), maximum percent slope in the 500 m buffer (+) and percent cover of herbaceous-emergent wetland in 1000 m buffer (-). The absence of fish from eastern lakes is related to the lack of a stream within 50 m of the lake. 6. The models predict that a total of 4% (131) of study lakes in the two regions were historically fishless, with the eastern region hosting a greater proportion than the western region. 7. We verified the model predictions with two

Hexabromocyclododecane Flame Retardant Isomers in Sediments from Detroit River and Lake Erie of the Laurentian Great Lakes of North America.

PubMed

Letcher, Robert J; Lu, Zhe; Chu, Shaogang; Haffner, G Douglas; Drouillard, Ken; Marvin, Christopher H; Ciborowski, Jan J H

2015-07-01

Sediments collected in 2004 from along the Detroit River (n = 19) and across all of Lake Erie (n = 18) were analyzed for isomers of the flame retardant chemical, hexabromocyclododecane (HBCD), using liquid chromatography-tandem mass spectrometry. Sediment samples had ΣHBCD concentrations ranging from not detected to 1.6 ng/g d.w. γ-HBCD (56 %-100 % of ΣHBCDs) was the predominate isomer, observed in 7 of 19 samples from the Detroit River and 6 of 18 samples from Lake Erie (all within the western basin). α-HBCD was found in 4 Detroit River and 2 Lake Erie western basin sites, while β-HBCD was only in two Detroit River samples. High ΣHBCD concentrations (>100 ng/g d.w.) were found in two sludge samples from two Windsor, ON, wastewater treatment plants that feed into the Detroit River upstream. HBCD contamination into the Detroit River is a major input vector into Lake Erie and with an apparent sediment dilution effect moving towards the eastern basin.

Suppression of invasive lake trout in an isolated backcountry lake in Glacier National Park

USGS Publications Warehouse

Fredenberg, C. R.; Muhlfeld, Clint C.; Guy, Christopher S.; D'Angelo, Vincent S.; Downs, Christopher C.; Syslo, John M.

2017-01-01

Fisheries managers have implemented suppression programmes to control non-native lake trout, Salvelinus namaycush (Walbaum), in several lakes throughout the western United States. This study determined the feasibility of experimentally suppressing lake trout using gillnets in an isolated backcountry lake in Glacier National Park, Montana, USA, for the conservation of threatened bull trout, Salvelinus confluentus (Suckley). The demographics of the lake trout population during suppression (2009–2013) were described, and those data were used to assess the effects of suppression scenarios on population growth rate (λ) using an age-structured population model. Model simulations indicated that the population was growing exponentially (λ = 1.23, 95% CI: 1.16–1.28) prior to suppression. However, suppression resulted in declining λ(0.61–0.79) for lake trout, which was concomitant with stable bull trout adult abundances. Continued suppression at or above observed exploitation levels is needed to ensure continued population declines.

Silvics of western white pine

Treesearch

Charles A. Wellner

1962-01-01

Western white pine grows along west coast mountain ranges from Vancouver Island and the Homathko River on the adjacent mainland in British Columbia southward to the San Bernardino Mountains of southern California (13, 65, 75, 83). In the interior its range is from Quesnel Lake through the Selkirk Mountains of British Columbia southward into northern Idaho, western...

Salina-margin tepees, pisoliths, and aragonite cements, Lake MacLeod, Western Australia: Their significance in interpreting ancient analogs

NASA Astrophysics Data System (ADS)

Robertson Handford, C.; Kendall, Alan C.; Prezbindowski, Dennis R.; Dunham, John B.; Logan, Brian W.

1984-09-01

Tepee structures, banded aragonite cements, and pisoliths are currently forming in Lake MacLeod, a carbonate-evaporite salina in Western Australia. Although Lake MacLeod is separated from the Indian Ocean by a barrier, it lies 3 4 m below sea level, which promotes the seepage of seawater through the barrier and its discharge from vents and seepage mounds around the margin of the salina. Discharging waters have precipitated and diagenetically altered carbonate sediments within these seepage mounds to form tepee structures of lithified protodolomite overlying cavities that are lined with banded aragonite cement and floored by both cement and pisoliths. Significant variations in δ18O (5.1‰ PDB) and δ13C (5.5‰ PDB) of the aragonite cements were documented and are thought to record shifts in the isotopic composition of the water brought about by the effects of evaporation, influx of meteoric water, and oxidation of organic water. Carbon-14 dating of cements indicates that cementation began about 3400 B.P. and has proceeded at a rate of about 0.2 to 0.4 mm/100 yr, the highest rate occurring during evaporative episodes. By analogy with Lake MacLeod and other Australian salinas, peritidal tepee structures and associated diagenetic carbonates in the Permian Capitan Reef complex may owe their origin to speleanlike diagenesis operative in a marine groundwater discharge zone.

INFLUENCES OF HYDROLOGY ON NUTRIENT DYNAMICS IN LAKE SUPERIOR COASTAL WETLANDS

EPA Science Inventory

Little is known about the role of the coastal wetlands (CWs) of Lake Superior in modifying or contributing to nutrient fluxes from watersheds to the lake. We are studying factors controlling nutrient retention and transformation of CWs in Western Lake Superior. CWs may be unique ...

Evidence of Regional Warming during the 20th Century in Alpine and Subalpine Lakes in the Western United States

NASA Astrophysics Data System (ADS)

Porinchu, D.; Reinemann, S.; Potito, A.; Moser, K.; MacDonald, G.; Munroe, J.; Mark, B.; Box, J.

2007-12-01

Subfossil midge analyses have been used to develop high-resolution (sub-decadal) reconstructions of 20th century temperature change in the Sierra Nevada, CA with success. Expansion of this earlier work to additional sites in the western United States suggests that a widespread increase in lake water temperatures has occurred in this region during the late 20th and early 21st centuries. Inference models for summer surface water temperature (SSWT) were developed combining midge abundance data from 56 lakes in the eastern Sierra Nevada, California, with subfossil midge remains from the Uinta Mountains, UT. The newly merged Sierra Nevada-Uinta Mountains calibration set contains a greater diversity of chironomid assemblages and spans a wider SSWT range than the previously published Sierra Nevada calibration set. The lakes in the merged calibration set spanned elevation, depth, and SSWT temperature ranges of 900 m, 12.7 m, and 11.3 °C, respectively. A robust inference model for SSWT (3-component WA-PLS), based on 90 lakes, had a high coefficient of determination (r2jack = 0.66) and a low RMSEP (1.4 °C). The midge-based SSWT inference model was applied to subfossil chironomid remains extracted from well-dated sediment sequences recovered from alpine and subalpine lakes in the Sierra Nevada, CA, Snake Range, NV and Uinta Mountains, UT. A close correspondence exists between the chironomid-inferred temperature profiles for the 20th and 21st centuries and mean July or summer temperatures measured at nearby meteorological stations. Application of this midge-based SSWT inference model to other intact, late Quaternary sedimentary sequences found in subalpine and alpine lakes in the Great Basin will help resolve the impact of late Quaternary and recent climate change in this region, improve our understanding of regional climate and aquatic ecosystem variability, and can be used to monitor the effects of climate change on aquatic ecosystems and establish 'baseline' conditions

High resolution mapping of NO2 column densities along the western shore of Lake Michigan and the Los Angeles Basin during May/June 2017

NASA Astrophysics Data System (ADS)

Judd, L. M.; Al-Saadi, J. A.; Janz, S. J.; Kowalewski, M. G.; Szykman, J.; Swap, R.; Abuhassan, N.; Cede, A.; Valin, L.; Williams, D.; Stanier, C. O.

2017-12-01

The airborne Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) UV/VIS mapping spectrometer was used to make measurements for the Lake Michigan Ozone Study (LMOS) along the western shore of Lake Michigan and for the Student Airborne Research Program (SARP) in the Los Angeles Basin during May and June 2017. This instrument has the capability of retrieving NO2 column densities at sub-urban spatial scales (nominally 250 m x 250 m) and is being used as a testbed for future geostationary air quality retrievals. LMOS was a multi-agency collaborative observational effort to better understand ozone pollution along Lake Michigan's western shore, where coastal monitors exceed current ozone standards. With 21 science flights during the 5-week campaign period, GeoTASO acquired data for constraining emissions along the western coast of Lake Michigan and observed how these emissions dispersed and influenced the local air quality. During SARP flights, GeoTASO was used to map the Los Angeles Basin five times over two days, observing NO2 Differential Slant Column densities (DSCs) ranging from over 50x1015 molecules cm-2 down to GeoTASO's detection limit ( 1.5x1015 molecules cm-2 at 250 m x 250 m). This work presents the spatial distribution of preliminary NO2 DSCs observations over both research areas, and shows how this it changed at hourly to multi-day timescales under varying meteorological conditions. Both LMOS and SARP included coincident column NO2 measurements from networks of ground-based Pandora spectrometers specifically set up for these campaigns, and a comparison of coincident observations will be shown. Consistent features were observed throughout these flights, including continual emission `hot-spots' and the redistribution of NO2 plumes by land-water circulations. One goal of this work is to investigate how the fine spatial features observed (e.g. power plant plumes) will be depicted in satellite observations at coarser spatial resolutions. These

Modern lacustrine stromatolites, Walker Lake, Nevada

NASA Astrophysics Data System (ADS)

Osborne, Robert H.; Licari, Gerald R.; Link, Martin H.

1982-05-01

The Walker River drainage basin occupies about 10,000 km 2 in western Nevada and parts of California and is essentially a closed hydrologic system which drains from the crest of the Sierra Nevada in California and terminates in Walker Lake, Nevada. Walker Lake trends north and is about 27.4 km long and 8 km wide with water depths exceeding 30.5 m. The lake is situated in an asymmetric basin with steep alluvial fans flanking the western shoreline (Wassuk Range) and more gentle but areally more extensive alluvial fans flanking the eastern shoreline (Gillis Range). Exposed lake terraces and the present shoreline of Walker Lake record a sequence of Pleistocene and Holocene stromatolitic and tufaceous carbonate deposits. Small generalized and columnar stromatolites, frequently encrusted on exposed coarse-grained clasts or bedrock, are present along parts of the nearshore margin of Walker Lake and at elevated lake stands. Columnar stromatolites as much as 4 cm high are subcylindrical to club shaped discrete, and laterally linked at the base with local branching. These digitate stromatolites start as wavy, generalized stromatolites which are vertically transitional to small, laterally linked cabbage heads with laminae which thicken over the crests. Although algal structures are not well preserved in the older stromatolites, recent precipitation of low magnesium calcite occurs as smooth encrustations and as tiny mounds which are consistently associated with a diverse, seasonally variable, green and blue-green algal community including Cladophora glomerata, Ulothrix (cf. aequalis), Gongrosira, Schizothrix, Amphithrix janthina, Calothrix, Homeothrix, Spirulina, Anabaena, Lyngbya, and Entophysalis. Cladophora glomerata and a species of Ulothrix, which are the two most abundant algae within the Walker Lake stromatolite community, are known to condition semi-alkaline lake water by the removal of CO 2 from bicarbonate during photosynthesis. Such conditioning results in the

Particle formation above natural and simulated salt lakes

NASA Astrophysics Data System (ADS)

Kamilli, Katharina A.; Ofner, Johannes; Sattler, Tobias; Krause, Torsten; Held, Andreas

2014-05-01

Originally, Western Australia was covered with Eucalyptus trees. Large scale deforestation for agricultural purposes led to rising ground water levels and brought dissolved salts and minerals to the surface. Nowadays, Western Australia is known for a great plenty of salt lakes with pH levels reaching from 2.5 to 7.1. The land is mainly used for wheat farming and livestock and becomes drier due to the lack of rain periods. One possible reason could be the formation of ultrafine particles from salt lakes, which increases the number of cloud condensation nuclei, and thus potentially suppresses precipitation. Several field campaigns have been conducted between 2006 and 2011 with car-based and airborne measurements, where new particle formation has been observed and has been related to the Western Australian salt lakes (Junkermann et al., 2009). To identify particle formation directly above the salt lakes, a 2.35 m³ PTFE chamber was set up above several lakes in 2012 and 2013. Inside the chamber, photochemistry may take place whereas mixing through wind or advection of already existing particles is prevented. Salt lakes with a low pH level led to strongly increased aerosol formation. Also, the dependence on meteorological conditions has been examined. To obtain chemical information of the newly formed particles, during the chamber experiments also aerosol filter samples have been taken. The analysis of the anions by ion chromatography in 2012 showed an 8 to 17 times higher concentration of Cl- than SO42-, which led to the assumption that particle formation may have been influenced by halogens. As reference experiments, laboratory based aerosol smog-chamber runs were performed to examine halogen induced aerosol formation under atmospheric conditions using simulated sunlight and the simplified chemical composition of a salt lake. The mixture included FeSO4, NaCl and Na2SO4. After adding α-pinene to the simulated salt lake, a strong nucleation event began comparable to

Particle formation above natural and simulated salt lakes

NASA Astrophysics Data System (ADS)

Kamilli, Katharina; Ofner, Johannes; Sattler, Tobias; Krause, Torsten; Zetzsch, Cornelius; Held, Andreas

2013-04-01

Western Australia was originally covered by natural eucalyptus forests, but land-use has changed considerably after large scale deforestation from 1950 to 1970. Thus, the ground-water level rose and brought dissolved salts and minerals to the surface. Nowadays, Western Australia is known for a great plenty of salt lakes with pH levels reaching from 2.5 to 7.1. The land is mainly used for wheat farming and livestock and becomes drier due to the lack of rain periods. One possible reason could be the formation of ultrafine particles from salt lakes, which increases the number of cloud condensation nuclei and thus potentially suppresses precipitation. Several field campaigns have been conducted between 2006 and 2011 with car-based and airborne measurements, where new particle formation has been observed and has been related to the Western Australian salt lakes (Junkermann et al., 2009). To identify particle formation directly above the salt lakes, a 1.5 m³ Teflon chamber was set up above several lakes in 2012. Inside the chamber, photochemistry may take place whereas mixing through wind or advection of already existing particles is prevented. Salt lakes with a low pH level lead to strongly increased aerosol formation. As salt lakes have been identified as a source for reactive halogen species (RHS; Buxmann et al., 2012) and RHS seem to interact with precursors of secondary organic aerosol (SOA), they could be producers of halogen induced secondary organic aerosol (XOA) (Ofner et al., 2012). As reference experiments, laboratory based aerosol smog-chamber runs were performed to examine XOA formation under atmospheric conditions using simulated sunlight and the chemical composition of a chosen salt lake. After adding α-pinene to the simulated salt lake, a strong nucleation event began in the absence of ozone comparable to the observed events in Western Australia. First results from the laboratory based aerosol smog-chamber experiments indicate a halogen-induced aerosol

Morphological variation of siscowet lake trout in Lake Superior

USGS Publications Warehouse

Bronte, C.R.; Moore, S.A.

2007-01-01

Historically, Lake Superior has contained many morphologically distinct forms of the lake trout Salvelinus namaycush that have occupied specific depths and locations and spawned at specific times of the year. Today, as was probably the case historically, the siscowet morphotype is the most abundant. Recent interest in harvesting siscowets to extract oil containing omega-3 fatty acids will require additional knowledge of the biology and stock structure of these lightly exploited populations. The objective of this study was to determine whether shape differences exist among siscowet populations across Lake Superior and whether these shape differences can be used to infer stock structure. Morphometric analysis (truss protocol) was used to differentiate among siscowets sampled from 23 locations in Lake Superior. We analyzed 31 distance measurements among 14 anatomical landmarks taken from digital images of fish recorded in the field. Cluster analysis of size-corrected data separated fish into three geographic groups: The Isle Royale, eastern (Michigan), and western regions (Michigan). Finer scales of stock structure were also suggested. Discriminant function analysis demonstrated that head measurements contributed to most of the observed variation. Cross-validation classification rates indicated that 67–71% of individual fish were correctly classified to their region of capture. This is the first study to present shape differences associated with location within a lake trout morphotype in Lake Superior.

Molecular evidence of undescribed Ceratonova sp. (Cnidaria: Myxosporea) in the freshwater polychaete, Manayunkia speciosa, from western Lake Erie

USGS Publications Warehouse

Malakauskas, David M.; Snipes, Robert Benjamin; Thompson, Ann M.; Schloesser, Donald W.

2016-01-01

We used PCR to screen pooled individuals of Manayunkia speciosa from western Lake Erie, Michigan, USA for myxosporean parasites. Amplicons from positive PCRs were sequenced and showed a Ceratonova species in an estimated 1.1% (95% CI = 0.46%, 1.8%) of M. speciosa individuals. We sequenced 18S, ITS1, 5.8S, ITS2 and most of the 28S rDNA regions of this Ceratonova sp., and part of the protein-coding EF2 gene. Phylogenetic analyses of ribosomal and EF2 sequences showed the Lake Erie Ceratonova sp. is most similar to, but genetically distinct from, Ceratonova shasta. Marked interspecific polymorphism in all genes examined, including the ITS barcoding genes, along with geographic location suggests this is an undescribed Ceratonova species. COI sequences showed M. speciosa individuals in Michigan and California are the same species. These findings represent a third parasite in the genus Ceratonovapotentially hosted by M. speciosa.

Density-independent survival of wild lake trout in the Apostle Islands area of Lake Superior

USGS Publications Warehouse

Bronte, Charles R.; Schram, Stephen T.; Selgeby, James H.; Swanson, Bruce L.

1995-01-01

The lake trout (Salvelinus namaycush) stock at Gull Island Shoal in western Lake Superior was one of only a few stocks of lean lake trout in the Great Lakes that survived overfishing and predation by the sea lamprey (Petromyzon marinus). Since the mid 1960s, the abundance of wild recruits measured at age 0 and the number of age-7 to -11 wild fish recruited to the fishable stock have increased. We used the Varley-Gradwell method to test for density-dependent survival between these life stages. Survival from age-0 to ages 7–11 was not affected by increasing density, which suggests that further increases in recruitment and stock size are still possible. We suggest that testing for the existence of density-dependent survival can be used to indicate when lake trout populations are rehabilitated.

Patterns of organochlorine contamination in lake trout from Wisconsin waters of the Great Lakes

USGS Publications Warehouse

Miller, Michael A.; Madenjian, Charles P.; Masnado, Robert G.

1992-01-01

To investigate spatial and temporal patterns of organochlorine contamination in lake trout from Wisconsin waters of the Great Lakes, we examined laboratory contaminant analysis data of muscle tissue samples from Lake Michigan (n=317) and Lake Superior (n=53) fish. Concentrations of polychlorinated biphenyls (PCBs), chlordane, and dieldrin, reported as mg/kg wet weight in 620 mm to 640 mm mean length Lake Michigan lake trout, decreased over time. Mean total PCB concentration declined exponentially from 9.7 in 1975 to 1.9 in 1990. Total chlordane concentration declined 63 percent from 0.48 in 1983 to 0.18 in 1990, and dieldrin declined 52 percent during this same period, from 0.21 to 0.10. The bioaccumulation rate of PCBs is significantly lower for lake trout inhabiting Lake Michigan's midlake reef complex, compared to lake trout from the nearshore waters of western Lake Michigan. Organochlorine compound concentrations were greater in Lake Michigan lake trout than Lake Superior fish. Lake Superior lean lake trout and siscowet exhibited similar rates of PCB bioaccumulation despite major differneces in muscle tissue lipid content between the two subspecies. The lack of a significant difference in the PCB bioaccumulation rates of lean trout and siscowet suggests that lipid content may not be an important factor influencing PCB bioaccumulation in lake trout, within the range of lipid concentrations observed. Relative concentrations of the various organochlorine contaminants found in lake trout were highly correlated, suggesting similar mass balance processes for these compounds. Evidence presented revealing spatial and temporal patterns of organochlorine contamination may be of value in reestablishing self-sustaining populations of lake trout in Lake Michigan.

Seismic Data Reveal Lake-Level Changes in Lake Issyk-Kul, Kyrgyzstan

NASA Astrophysics Data System (ADS)

Gebhardt, C.; Spiess, V.; Keil, H.; Sauermilch, I.; Oberhänsli, H.; Abdrakhmatov, K.; De Batist, M. A.; Naudts, L.; De Mol, L.

2013-12-01

Lake Issyk-Kul is located in an intramontane basin of the Tien Shan, Kyrgyzstan, Central Asia, at 1607 m above sea level. It has formed in a tectonically active region with W-E striking major thrust zones both N and S of the lake. The lake is elongated with 180 km in W-E and 60 km in S-N direction and a water depth of roughly 670 m at its central plain. With a surface area of 6232 km2 and a total water colume of around 1736 km3, Lake Issyk-Kul is the second largest lake in the higher altitudes (De Batist et al., 2002). Two large delta areas have formed at the E and W end. Steep slopes at both the N and S shore separate rather narrow, shallow shelf areas from the central deeper plain. First seismic data of lake Issyk-Kul were acquired in 1982 by the Moscow University with a total of 31 profiles across the lake. In 1997 and 2001, a second and third seismic survey of the lake were carried out by the group of Marc De Batist (Ghent, Belgium) in cooperation with the Royal Museum of Central Africa (Tervuren, Belgium) and the SBRAS (Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia) using a sparker system with a single-channel streamer. These surveys were recently completed by a fourth expedition carried out by the University of Bremen in April 2013. During this expedition, 33 additional profiles were acquired with an airgun and a multi-channel streamer. The sparker surveys mostly cover the delta and shelf areas in high detail, while the airgun survey covers the deeper parts of the lake with penetration beyond the first multiple. Bathymetry data reveal that at the delta areas, the shelf is divided into two parts. The shallower comprises the part down to 110 m water depth with an average inclination of 0.5°, while the deeper part reaches from 110 m to 300 m water depth with an average slope inclination of 1°. Incised paleo-river channels of up to 2-3 km width and 50 m depth are visible both on the eastern and western shelf, but are limited to the

Novel reassortant clade 2.3.4.4 avian influenza A (H5N8) virus in a grey heron in South Korea in 2017.

PubMed

Woo, Chanjin; Kwon, Jung-Hoon; Lee, Dong-Hun; Kim, Youngsik; Lee, Kwanghee; Jo, Seong-Deok; Son, Ki Dong; Oem, Jae-Ku; Wang, Seung-Jun; Kim, Yongkwan; Shin, Jeonghwa; Song, Chang-Seon; Jheong, Weonhwa; Jeong, Jipseol

2017-12-01

We report the identification of a novel reassortant clade 2.3.4.4 H5N8 virus from a dead grey heron in Korea in 2017. Outbreaks of clade 2.3.4.4 H5 HPAIVs have been reported worldwide, and they have evolved into multiple genotypes among wild birds. Phylogenetic analysis indicated that this virus likely originated from Qinghai Lake and Western Siberia and further evolved through reassortment with Eurasian LPAI during the 2016 fall migration of wild birds. Enhanced surveillance and comparative genetic analysis will help to monitor the further evolution and dissemination of clade 2.3.4.4 HPAIVs.

Freshwater diatomite deposits in the western United States

USGS Publications Warehouse

Wallace, Alan R.; Frank, David G.; Founie, Alan

2006-01-01

Freshwater diatomite deposits in the Western United States are found in lake beds that formed millions of years ago. These diatom-rich sediments are among the Nation's largest commercial diatomite deposits. Each deposit contains billions of tiny diatom skeletons, which are widely used for filtration, absorption, and abrasives. New studies by the U.S. Geological Survey (USGS) are revealing how ancient lakes in the Western States produced such large numbers of diatoms. These findings can be used by both land-use managers and mining companies to better evaluate diatomite resources in the region.

Sedimentary facies and environmental ichnology of a ?Permian playa-lake complex in western Argentina

USGS Publications Warehouse

Zhang, G.; Buatois, L.A.; Mangano, M.G.; Acenolaza, F.G.

1998-01-01

A moderately diverse arthropod icnofauna occurs in ?Permian ephemeral lacustrine deposits of the Paganzo Basin that crop out at Bordo Atravesado, Cuesta de Miranda, western Argentina. Sedimentary successions are interpreted as having accumulated in a playa-lake complex. Deposits include three sedimentary facies: (A) laminated siltstone and mudstone: (B) current-rippled cross-laminated very fine grained sandstone: and (C) climbing and wave-rippled cross-laminated fine-grained sandstone deposited by sheet floods under wave influence in the playa-lake complex. Analysis of facies sequences suggests that repeated vertical facies associations result from transgressive regressive episodes of variable time spans. The Bordo Atravesado ichnofauna includes Cruziana problematica, Diplocraterion isp., cf. Diplopadichnus biformis, Kouphichnium? isp., Merostomichnites aicunai, Mirandaichnium famatinense, Monomorphichnus lineatus, Palaeophyeus tubularis, Umfolozia sinuosa and Umfolozia ef. U. longula. The assemblage is largely dominated by arthropod trackways and represents an example of the Scoyenia ichnofacies. Trace fossils are mostly preserved as hypichnial ridges on the soles of facies C beds, being comparatively rare in facies A and B. Ichnofossil preservation was linked to rapid influx of sand via sheet floods entering into the lake. Four taphonomic variants (types 1-4) are recognized, each determined by substrate consistency and time averaging. Type 1 is recorded by the presence of low density assemblages consisting of poorly defined trackways, which suggests that arthropods crawled in soft, probably slightly subaqueous substrates. Type 2 is represented by low to moderate density suites that include sharply defined trackways commonly associated with mud cracks, suggesting that the tracemakers inhabited a firm, desiccated lacustrine substrate. Type 3 displays features of types 1 and 2 and represents palimpsestic bedding surfaces, resulting from the overprint of terrestrial

Isolation and Classification of Fungal Whitefly Entomopathogens from Soils of Qinghai-Tibet Plateau and Gansu Corridor in China.

PubMed

Dong, Tingyan; Zhang, Bowen; Jiang, Yanfang; Hu, Qiongbo

2016-01-01

Qinghai-Tibet Plateau and Gansu Corridor of China with distinct geographic and climatic conditions are remote and less disturbed by humans, in which are likely to find some new strains of fungal entomopathogens against B-biotype whiteflies that is a very important invading pest worldwide. In this research, nineteen strains among six species of entomogenous fungi were isolated from the soil samples collected from 32 locations in Qinghai-Tibet Plateau and Gansu Corridor. From the data of isolation rates, it was indicated that the good biodiversity of entomogenous fungi was found in the soil covered good vegetations. On the contrary, no strains were isolated from the desert areas. In addition, the dominant species, Isaria fumosorosea and Metarhizium anisopliae var. anisopliae in the Qinghai-Tibet Plateau are different from the strains of other places based on ITS genetic homology analysis. It was verified that the Qinghai-Tibet Plateau area was less disturbed by human, and the fungi in this place exchanged less compared with other regional species. All of these strains showed the pathogenicity against the B-biotype whitefly with the mortality of more than 30%. However, a few strains of Paecilomyces lilacinus, Lecanicillium psalliotae, Aspergillus ustus, I. fumosorosea and M. anisopliae var. anisopliae had better virulence with LC50s of 0.36-26.44×106 spores/mL on post-treatment day 6-7. Especially, the L. psalliotae strain LpTS01 was the greatest virulence with LC50 of 0.36×106spores/mL and LT50 of 4.23d. Our research thus presents some new insights to discover new entomopathogenic fungal strains used for B-biotype whitefly biocontrol.

Isolation and Classification of Fungal Whitefly Entomopathogens from Soils of Qinghai-Tibet Plateau and Gansu Corridor in China

PubMed Central

Jiang, Yanfang; Hu, Qiongbo

2016-01-01

Qinghai-Tibet Plateau and Gansu Corridor of China with distinct geographic and climatic conditions are remote and less disturbed by humans, in which are likely to find some new strains of fungal entomopathogens against B-biotype whiteflies that is a very important invading pest worldwide. In this research, nineteen strains among six species of entomogenous fungi were isolated from the soil samples collected from 32 locations in Qinghai-Tibet Plateau and Gansu Corridor. From the data of isolation rates, it was indicated that the good biodiversity of entomogenous fungi was found in the soil covered good vegetations. On the contrary, no strains were isolated from the desert areas. In addition, the dominant species, Isaria fumosorosea and Metarhizium anisopliae var. anisopliae in the Qinghai-Tibet Plateau are different from the strains of other places based on ITS genetic homology analysis. It was verified that the Qinghai-Tibet Plateau area was less disturbed by human, and the fungi in this place exchanged less compared with other regional species. All of these strains showed the pathogenicity against the B-biotype whitefly with the mortality of more than 30%. However, a few strains of Paecilomyces lilacinus, Lecanicillium psalliotae, Aspergillus ustus, I. fumosorosea and M. anisopliae var. anisopliae had better virulence with LC50s of 0.36–26.44×106 spores/mL on post-treatment day 6–7. Especially, the L. psalliotae strain LpTS01 was the greatest virulence with LC50 of 0.36×106spores/mL and LT50 of 4.23d. Our research thus presents some new insights to discover new entomopathogenic fungal strains used for B-biotype whitefly biocontrol. PMID:27228109

Occurrence of phosphorus, iron, aluminum, silica, and calcium in a eutrophic lake during algae bloom sedimentation.

PubMed

Li, Guolian; Xie, Fazhi; Zhang, Jin; Wang, Jingrou; Yang, Ying; Sun, Ruoru

2016-09-01

Phosphorus (P) in a water body is mainly controlled by the interaction between surface sediment and the overlying water column after the complete control of external pollution. Significant enhancement of P in a water body would cause eutrophication of lakes. Thus, a better understanding is needed of the occurrences of P between the sediment and water column in eutrophic lakes. Here, we measured total phosphorus (TP) and major elements (Fe, Al, Ca, Mn, Si) in the water column, and total nitrogen, organic matter, TP and major oxides (Fe 2 O 3 , Al 2 O 3 , CaO, SiO 2 ) in surface sediment of Chaohu Lake, a continuously eutrophic lake. The results showed that the rank of TP levels was western lake > eastern lake > southern lake. There were significantly positive correlations between TP (including water TP and sedimentary TP) and Fe, Al, Mn, while the correlation coefficients between water TP and sedimentary TP were -0.43, -0.41 and 0.18 for the western, eastern and southern lake respectively. The negative and significant correlations of water TP and sedimentary TP may indicate that the risk of sedimentary P release was great in the western and eastern lake during algae bloom sedimentation, while the southern lake showed weak P exchange between the sediment and water column.

Detours in long-distance migration across the Qinghai-Tibetan Plateau: individual consistency and habitat associations.

PubMed

Liu, Dongping; Zhang, Guogang; Jiang, Hongxing; Lu, Jun

2018-01-01

Migratory birds often follow detours when confronted with ecological barriers, and understanding the extent and the underlying drivers of such detours can provide important insights into the associated cost to the annual energy budget and the migration strategies. The Qinghai-Tibetan Plateau is the most daunting geographical barrier for migratory birds because the partial pressure of oxygen is dramatically reduced and flight costs greatly increase. We analyzed the repeated migration detours and habitat associations of four Pallas's Gulls Larus ichthyaetus across the Qinghai-Tibetan Plateau over 22 migration seasons. Gulls exhibited notable detours, with the maximum distance being more than double that of the expected shortest route, that extended rather than reduced the passage across the plateau. The extent of longitudinal detours significantly increased with latitude, and detours were longer in autumn than in spring. Compared with the expected shortest routes, proximity to water bodies increased along autumn migration routes, but detour-habitat associations were weak along spring migration routes. Thus, habitat availability was likely one, but not the only, factor shaping the extent of detours, and migration routes were determined by different mechanisms between seasons. Significant between-individual variation but high individual consistency in migration timing and routes were revealed in both seasons, indicating a stronger influence of endogenous schedules than local environmental conditions. Gulls may benefit from repeated use of familiar routes and stopover sites, which may be particularly significant in the challenging environment of the Qinghai-Tibetan Plateau.

Changes in growth and maturity of walleyes associated with stock rehabilitation in western Lake Erie, 1964-1983

USGS Publications Warehouse

Muth, Kenneth M.; Wolfert, David R.

1986-01-01

The precipitous decline in abundance of walleyes (Stizostedion vitreum vitreum) in western Lake Erie during the 1960s caused major concerns for the future of this resource. Mercury contamination in walleyes in 1970 resulted in a moratorium on commercial fishing in United States and Canadian waters. The opportunity arose for resource agencies to develop a plan for rehabilitation of the walleye stocks, and quota management for walleyes was begun in 1976. After 8 years, the resource had recovered dramatically and the estimated standing stock in 1983 was more than three times that in 1976. In the mid-1970s, however, certain detrimental changes suggested that self-regulatory mechanisms were occurring. The growth rate declined gradually but rather consistently. Growth changes were most evident for young-of-the-year (YOY), yearlings, and 2-year-old fish, which usually constituted more than 80% of the standing stock in 1976-1983. Average lengths of YOY fish decreased by nearly 50 mm (from about 240 mm in 1961 to 190 mm in 1983). Average lengths and weights of yearling and older fish began to decline after 1975 and decreased markedly after 1980. Historically, growth of walleyes in western Lake Erie exceeded that reported for many walleye populations in other waters. Another sign of self-regulation was an increasing delay in the onset of maturity. Most (usually more than 90%) of the yearling males were sexually mature each fall before 1979, but this percentage decreased to only 32 by fall 1983. Usually 80% or more of the age-II females were mature each fall during the 1960s and early 1970s, but this percentage decreased rapidly to only 7 by fall 1983. Prey fish populations declined somewhat in the early 1980s, and their ability to sustain the high abundance of walleyes is a great concern to resource managers.

Southern Illinois and Western Kentucky, USA

NASA Image and Video Library

1973-06-22

SL2-81-194 (22 June 1973) --- This view of southern Illinois and Western Kentucky (37.0N, 88.5W), with the winding Ohio River in between also illustrates the rich agriculture potential of the flood plains in the river bottom lands. To the east are the waters of Lake Kentucky and Lake Barkley which flow into the Ohio at Paducah, KY and may be seen stretching for several miles. Except for the Land Between the Lakes State Park, Extensive agriculture may be seen throughout the area. Photo credit: NASA

Northern goshawk monitoring in the western Great Lakes bioregion

USGS Publications Warehouse

Bruggeman, Jason E.; Andersen, David E.; Woodford, James E.

2011-01-01

Uncertainties about factors affecting Northern Goshawk (Accipiter gentilis) ecology and the status of populations have added to the challenge of managing this species. To address data needs for determining the status of goshawk populations, Hargis and Woodbridge (2006) developed a bioregional monitoring protocol based on estimating occupancy. The goal of our study was to implement this protocol and collect data to determine goshawk population status in the western Great Lakes (WGL) bioregion, which encompasses portions of Minnesota, Wisconsin, and Michigan, and is a mixture of private and public property. We used 366 goshawk nest locations obtained between 1979 and 2006 throughout the WGL bioregion to develop a model of landscape use consisting of forest canopy cover and land-cover covariates. We then used the model to develop a stratified sampling design for selecting 600-ha Primary Sampling Units (PSUs) to survey for goshawks. Project collaborators surveyed 86 PSUs for goshawk presence using broadcasted calls twice between mid-May and mid-August 2008, and recorded 30 goshawk detections in 21 different PSUs. Seventy-four percent of detections occurred at call stations with canopy closure >75%. Goshawk detection probabilities were 0.549 ± 0.118 (standard error) for the first visit to PSUs and 0.750 ± 0.126 for the second visit. We estimated the proportion of PSUs occupied by goshawks as 0.266 ± 0.047, which corresponded to 5184 ± 914 PSUs occupied by goshawks in our study area and suggested that goshawks are widely, but sparsely, distributed throughout the WGL bioregion.

Ptilagrostis contracta (Stipeae, Poaceae), a New Species Endemic to Qinghai-Tibet Plateau.

PubMed

Zhang, Zhong-Shuai; Li, Ling-Lu; Chen, Wen-Li

2017-01-01

A new species, Ptilagrostis contracta, endemic to Qinghai-Tibet Plateau is described and illustrated. It is distinguished from other species in Ptilagrostis by having contracted panicles, 1-geniculate awns with hairy columns and scabrous bristles and evenly pubescent lemmas. Evidence from lemma epidermal pattern, cytology and molecular phylogenetic analyses based on the nuclear ITS sequence data confirm its systematic position in Ptilagrostis.

Trends in phosphorus loading to the western basin of Lake Erie

EPA Science Inventory

Dave Dolan spent much of his career computing and compiling phosphorus loads to the Great Lakes. None of his work in this area has been more valuable than his continued load estimates to Lake Erie, which has allowed us to unambiguously interpret the cyanobacteria blooms and hypox...

Lake Balkhash, Kazakhstan seen from STS-59

NASA Image and Video Library

1994-04-14

STS059-209-081 (9-20 April 1994) --- Lake Balkhash, in eastern Kazakhstan, is some 300 miles long. The lake, frozen in this scene, thawed noticeably during the mission. The shape of the lake is controlled by the delta of the Ili River, which flows from the Tien Shan Mountains in western China across this arid steppe. SRL scientists will use radar data to study the microwave effects of differences in soil moisture, and in freezing or thawing, on the deltaic sediments. Hasselblad camera.

Management strategies for sustainable western water

Treesearch

Scott Tyler; Sudeep Chandra; Gordon Grant

2017-01-01

With the effects of the dramatic western US drought still reverberating through the landscape, researchers gathered in advance of the 20th annual Lake Tahoe Summit to discuss western US water issues in the 21st century. This two-day workshop brought together ~40 researchers from universities and agencies (federal and state) to discuss the prospects that...

Stratigraphic framework and lake level history of Lake Kivu, East African Rift

NASA Astrophysics Data System (ADS)

Wood, Douglas A.; Scholz, Christopher A.

2017-10-01

Sediment cores and seismic reflection data acquired from the eastern basin of Lake Kivu, Rwanda reveal extensive limnologic variations due to changes in regional climate and basin structure. The eastern basin of the lake contains a sedimentary wedge which is > 1.5 km in thickness on its western side, and basal sediments are estimated to be at least 1.5 million years old. Sediments are likely to be thicker and older than this in the northern, Congolese basin of the lake. Above the ∼300 m iosbath only a thin layer of Holocene sediments are observed indication that this may have been the lake's high stand prior to that time. There are at least three erosional unconformities interpreted as desiccation or near-desiccation events which are estimated to have occurred at ∼475 ka, ∼100 ka, and ∼20 ka; the two most recent of these low stages likely developed during the African Megadrought and Last Glacial Maximum (LGM) periods. Following the LGM, the water levels rose to form a ∼100 m deep lake with its surface ∼370 m below the current lake level. The lake remained near that level for several thousand years and during this time the Virunga Volcanic Province expanded. At ∼12.2 ka a change to wetter climate conditions rapidly filled the lake to spill out of the Bukavu Bay basin southward toward Lake Tanganyika. Tephra sampled from the cores show that there have been at least 24 large local volcanic events since the early Holocene lake transgression.

Niche conservatism in Gynandropaa frogs on the southeastern Qinghai-Tibetan Plateau.

PubMed

Hu, Junhua; Broennimann, Olivier; Guisan, Antoine; Wang, Bin; Huang, Yan; Jiang, Jianping

2016-09-07

The role of ecological niche in lineage diversification has been the subject of long-standing interest of ecologists and evolutionary biologists. Gynandropaa frogs diversified into three independent clades endemic to the southeastern Qinghai-Tibetan Plateau. Here, we address the question whether these clades kept the same niche after separation, and what it tells us about possible diversification processes. We applied predictions in geographical (G)-space and tests of niche conservatism in environmental (E)-space. Niche models in G-space indicate separate regions with high suitability for the different clades, with some potential areas of sympatry. While the pair of central and eastern clades displayed the largest niche overlap for most variables, and strict niche equivalency was rejected for all clade-pairs, we found no strong evidence for niche divergence, but rather the signature of niche conservatism compared to null models in E-space. These results suggest a common ancestral ecological niche, and as such give good support to divergence through allopatric speciation, but alternative explanations are also possible. Our findings illustrate how testing for niche conservatism in lineage diversification can provide insights into underlying speciation processes, and how this information may guide further research and conservation practices, as illustrated here for amphibians on the Qinghai-Tibetan Plateau.

Intentional introduction of Artemia sinica (Anostraca) in the high-altitude Tibetan lake Dangxiong Co: the new population and consequences for the environment and for humans

NASA Astrophysics Data System (ADS)

Jia, Qinxian; Anufriieva, Elena; Liu, Xifang; Kong, Fanjing; Shadrin, Nickolai

2015-11-01

The imbalance between supply and demand of Artemia cysts in China and around the world is increasing now. Salt lakes in Tibet may contribute to the solution of the problem. In Northern Tibet there are 26 saline lakes whose salinity and temperature may support Artemia survival at an altitude of 4 000-5 100 m. We found Artemia in 15 of these lakes. The saline lakes with Artemia populations mainly belong to the shallow basin lakes, and the majority of these lakes are small in area. The total area of lakes without Artemia is more than 1 000 km2. Lake Dangxiong Co (Co means lake in Tibet) was chosen for the intentional introduction of Artemia sinica. In 2004, 850 g of A. sinica cysts, originating from Qinghai, were introduced in the lake. Surveys in 2006-2014 showed that the average abundance of Artemia adults in the lake gradually increased from 20 ind./m3 in 2006 to 1950 ind./m3 in 2013. We assume that two subpopulations of A. sinica, separated by depth, may exist in the lake. The new Artemia population caused an increase in the number of species of phytoplankton and heterotrophic protozoa with a decrease of their total abundance. Water transparency also increased. Dominance in phytoplankton passed from cyanobacteria to diatoms. Changes occurred not only in the lake ecosystem; the number of water birds using the lakes also dramatically increased. Preliminary calculations showed that is it possible to harvest at least about 150 t cysts per year from the lake as well as 3.2 thousand tons of frozen or 350 t of dried biomass of adult Artemia.

Life history of the spottail shiner (Notropis hudsonius) in southeastern Lake Michigan, the Kalamazoo River, and western Lake Erie

USGS Publications Warehouse

Wells, LaRue; House, Robert

1974-01-01

Young shiners started growing earlier in the year than older ones in all three waters. Males and females of the same age resumed growth at about the same time. The growing season began as early as mid-May in the Kalamazoo River and continued as late as September or early October in the other two waters. Small spottail shiners in Lake Michigan and the Kalamazoo River weighed about the same at a given length, but at lengths greater than about 100 mm the lake fish were heavier. In all three waters, spottail shiners matured at about the same length, and males at a somewhat smaller size than females. Smallest mature fish were 65-69 mm long, and the largest immatures were 80-84 mm. In Lake Michigan about half and in Lake Erie about three-quarters of age-I fish were mature, as were all age-II fish in both lakes. In the Kalamazoo River a few fish of age II and all of age III were mature. The spawning season in Lake Michigan in 1964 was from late June or early July to late July, whereas in 1972, which had a colder spring, spawning occurred from mid-July to late August or early September. All shiners in the Kalamazoo River had spawned by the end of June if 1964. Lake Erie spottail shiners spawned during early June to early or mid-July in 1958. Spottail shiners 87-143 mm long from the different waters contained 915 to 8,898 mature eggs.

Assessment of Climate Driven Dynamics of Active Layer, Hydrological and Vegetation Status at the Qinghai-Tibet Plateau Using Dynamic Global Vegetation Model

NASA Astrophysics Data System (ADS)

Yang, Y.

2014-12-01

Extensive permafrost degradation starting from 1970s is observed at the Qinghai-Tibet Plateau , China. Degradation is attributed to an increase in mean annual ground temperature 0.1◦-0.5◦ C with mainly winter warming. The construction of Qinghai-Tibet Railway also influenced a state of permafrost in the area Permafrost degradation caused negative environmental consequences in the area. The areas covered by sand are expanding steadily making large concern of accelerating desertification. The general pathway of future joint dynamics of permafrost, vegetation and hydrological status at the Qinghai-Tibet Plateau is still poorly understood and foreseeable. Hydrology in the area is determined by heat-moisture dynamics of active layer. This dynamics is highly non-linear and depends as on external climatic variables temperature and precipitation, so on soil and rock properties (amount of sand against aeolian deposits in the Plateau) as well as vegetation cover, which determine thaw and freeze processes in the active layer and evaporation and run-off. SEVER DGVM was modified to include heat-moisture dynamics of active layer in the Qinghai-Tibet Plateau. SEVER DGVM imitates processes in 10 plant functional types at coarse resolution of 0.5 degrees. This model imitates behavior of average individual of each plant type in each grid cell through simulation years. Each of those grid cells processed independently. First, this model starts from "bare soil", placing a bit of each plant type and giving them some time to grow and achieve equilibrium. Then, including active layer thickness and soil moisture dynamics into this layer, it allows assessment of potential environmental dynamics in this area. Simulations demonstrate further degradation of pastureland and accelerating desertification processes in this vitally important water feed area for many Asian rivers. Negative environmental problems related to operation of Qinghai-Tibet are also assessed.

Holocene Mass Transport Deposits in Western Norwegian fjords and lakes revealing prehistoric earthquake history of Scandinavia

NASA Astrophysics Data System (ADS)

Bellwald, B.; Hjelstuen, B. O.; Sejrup, H. P.; Kuvås, J.; Stokowy, T.

2016-12-01

The sensitivity of fjord sediments to seismic shaking makes fjord systems appropriate study sites when extending regional earthquake catalogs back in time and when estimating recurrence rates of prehistoric earthquakes in intraplate settings. In this study we compiled evidence of 140 postglacial mass movement events and their associated mass transport deposits (MTDs) from previously analyzed and new sediment cores and high-resolution seismic profiles from 22 fjord systems and six lakes in Western Norway. Evaluation of trigger mechanisms make us infer that most of these mass movement events were initiated by regional earthquakes, and that both climate-related processes and tsunamis most likely can be excluded as trigger mechanism for most of the events. A total of 33 individual earthquakes has been identified, which most likely outbalance the historically recorded events in magnitude, thus indicating magnitudes >6. Frequency plots of MTDs suggest high seismic activity in the early Holocene (11000-9700 cal. yrs BP), followed by seismic quiescence in the mid-Holocene before a seismic reactivation took place at 4000 cal. yrs BP. Coevally-triggered MTDs at 8100 cal. yrs BP are identified in all the archives, and are correlating with the age of the offshore Storegga slide. We estimate earthquake recurrence rates of 1/80 years directly after the last deglaciation of Western Norway (12800-11600 ca. yrs BP), 1/200 years for the early Holocene and 1/300 years for the last 4000 years. Our compilation suggests that the mid-Holocene is characterized by low seismic activity, suggesting recurrence rates of 1/1300 years. Comparisons of the Western Norwegian dataset with paleoseimologic studies of other previously glaciated intraplate settings indicate that both Scandinavia and the Alps show similar trends as Western Norway, whereas Eastern Canada is not correlating with the paleoseismologic trend of this study, which could be explained by different deglaciation histories.

Stock-specific advection of larval walleye (Sander vitreus) in western Lake Erie: Implications for larval growth, mixing, and stock discrimination

USGS Publications Warehouse

Fraker, Michael E.; Anderson, Eric J.; May, Cassandra J.; Chen, Kuan-Yu; Davis, Jeremiah J.; DeVanna, Kristen M.; DuFour, Mark R.; Marschall, Elizabeth A.; Mayer, Christine M.; Miner, Jeffery G.; Pangle, Kevin L.; Pritt, Jeremy J.; Roseman, Edward F.; Tyson, Jeffrey T.; Zhao, Yingming; Ludsin, Stuart A

2015-01-01

Physical processes can generate spatiotemporal heterogeneity in habitat quality for fish and also influence the overlap of pre-recruit individuals (e.g., larvae) with high-quality habitat through hydrodynamic advection. In turn, individuals from different stocks that are produced in different spawning locations or at different times may experience dissimilar habitat conditions, which can underlie within- and among-stock variability in larval growth and survival. While such physically-mediated variation has been shown to be important in driving intra- and inter-annual patterns in recruitment in marine ecosystems, its role in governing larval advection, growth, survival, and recruitment has received less attention in large lake ecosystems such as the Laurentian Great Lakes. Herein, we used a hydrodynamic model linked to a larval walleye (Sander vitreus) individual-based model to explore how the timing and location of larval walleye emergence from several spawning sites in western Lake Erie (Maumee, Sandusky, and Detroit rivers; Ohio reef complex) can influence advection pathways and mixing among these local spawning populations (stocks), and how spatiotemporal variation in thermal habitat can influence stock-specific larval growth. While basin-wide advection patterns were fairly similar during 2011 and 2012, smaller scale advection patterns and the degree of stock mixing varied both within and between years. Additionally, differences in larval growth were evident among stocks and among cohorts within stocks which were attributed to spatiotemporal differences in water temperature. Using these findings, we discuss the value of linked physical–biological models for understanding the recruitment process and addressing fisheries management problems in the world's Great Lakes.

Spatial and temporal trends in short-chain chlorinated paraffins in Lake Ontario sediments.

PubMed

Marvin, C H; Painter, S; Tomy, G T; Stern, G A; Braekevelt, E; Muir, D C G

2003-10-15

Short-chain chlorinated paraffins (polychlorinated-[C10-C13]-n-alkanes) were measured in Lake Ontario sediments collected during a lake-wide survey to characterize spatial and temporal trends in contamination. The Lake Ontario average SCCP sediment concentration was 49 ng/g (dry wt), which was somewhat higher than the lake-wide average for sigmaDDT (32 ng/g). Individual stations in each of the depositional basins exhibited the highest concentrations, ranging from 147 ng/g (dry wt) to 410 ng/g at an index station in the Niagara (western) basin. Relative average contributions of the carbon chain groups to total SCCPs on a lake-wide basis were as follows: sigmaC10 = 24%, sigmaC11 = 35%, sigmaC12 = 34%, sigmaC13 = 6.6%. Assessment of core profiles and estimates of SCCP fluxes indicated that an area of the western end of Lake Ontario is heavily impacted (SCCP flux of 170 microg/m2 yr) and potentially influenced by local industrial sources of SCCPs. Maximum accumulation of SCCPs in this area of the western basin occurred in the mid-1970s. In contrast, SCCP concentrations in a core from a site in the central area of the lake (SCCP flux of 8.0 microg/m2 yr) were more similar to levels characteristic of remote locations primarily impacted by atmospheric sources.

Mercury bioaccumulation in fishes from subalpine lakes of the Wallowa-Whitman National Forest, northeastern Oregon and western Idaho

USGS Publications Warehouse

Eagles-Smith, Collin A.; Herring, Garth; Johnson, Branden L.; Graw, Rick

2013-01-01

Mercury (Hg) is a globally distributed pollutant that poses considerable risks to human and wildlife health. Over the past 150 years since the advent of the industrial revolution, approximately 80 percent of global emissions have come from anthropogenic sources, largely fossil fuel combustion. As a result, atmospheric deposition of Hg has increased by up to 4-fold above pre-industrial times. Because of their isolation, remote high-elevation lakes represent unique environments for evaluating the bioaccumulation of atmospherically deposited Hg through freshwater food webs, as well as for evaluating the relative importance of Hg loading versus landscape influences on Hg bioaccumulation. The increase in Hg deposition to these systems over the past century, coupled with their limited exposure to direct anthropogenic disturbance make them useful indicators for estimating how changes in Hg emissions may propagate to changes in Hg bioaccumulation and ecological risk. In this study, we evaluated Hg concentrations in fishes of high-elevation, sub-alpine lakes in the Wallowa-Whitman National Forest in northeastern Oregon and western Idaho. Our goals were to (1) assess the magnitude of Hg contamination in small-catchment lakes to evaluate the risk of atmospheric Hg to human and wildlife health, (2) quantify the spatial variability in fish Hg concentrations, and (3) determine the ecological, limnological, and landscape factors that are best correlated with fish total mercury (THg) concentrations in these systems. Across the 28 study lakes, mean THg concentrations of resident salmonid fishes varied as much as 18-fold among lakes. Importantly, our top statistical model explained 87 percent of the variability in fish THg concentrations among lakes with four key landscape and limnological variables— catchment conifer density (basal area of conifers within a lake’s catchment), lake surface area, aqueous dissolved sulfate, and dissolved organic carbon. The basal area of conifers

Application of the ORCHIDEE global vegetation model to evaluate biomass and soil carbon stocks of Qinghai-Tibetan grasslands

NASA Astrophysics Data System (ADS)

Tan, Kun; Ciais, Philippe; Piao, Shilong; Wu, Xiaopu; Tang, Yanhong; Vuichard, Nicolas; Liang, Shuang; Fang, Jingyun

2010-03-01

The cold grasslands of the Qinghai-Tibetan Plateau form a globally significant biome, which represents 6% of the world's grasslands and 44% of China's grasslands. Yet little is known about carbon cycling in this biome. In this study, we calibrated and applied a process-based ecosystem model called Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) to estimate the C fluxes and stocks of these grasslands. First, the parameterizations of ORCHIDEE were improved and calibrated against multiple time-scale and spatial-scale observations of (1) eddy-covariance fluxes of CO2 above one alpine meadow site; (2) soil temperature collocated with 30 meteorological stations; (3) satellite leaf area index (LAI) data collocated with the meteorological stations; and (4) soil organic carbon (SOC) density profiles from China's Second National Soil Survey. The extensive SOC survey data were used to extrapolate local fluxes to the entire grassland biome. After calibration, we show that ORCHIDEE can successfully capture the seasonal variation of net ecosystem exchange (NEE), as well as the LAI and SOC spatial distribution. We applied the calibrated model to estimate 0.3 Pg C yr-1 (1 Pg = 1015 g) of total annual net primary productivity (NPP), 0.4 Pg C of vegetation total biomass (aboveground and belowground), and 12 Pg C of SOC stocks for Qinghai-Tibetan grasslands covering an area of 1.4 × 106 km2. The mean annual NPP, vegetation biomass, and soil carbon stocks decrease from the southeast to the northwest, along with precipitation gradients. Our results also suggest that in response to an increase of temperature by 2°C, approximately 10% of current SOC stocks in Qinghai-Tibetan grasslands could be lost, even though NPP increases by about 9%. This result implies that Qinghai-Tibetan grasslands may be a vulnerable component of the terrestrial carbon cycle to future climate warming.

Prevalence, Associated Risk Factors, and Phylogenetic Analysis of Toxocara vitulorum Infection in Yaks on the Qinghai Tibetan Plateau, China

PubMed Central

Li, Kun; Lan, Yanfang; Luo, Houqiang; Zhang, Hui; Liu, Dongyu; Zhang, Lihong; Gui, Rui; Wang, Lei; Shahzad, Muhammad; Sizhu, Suolang; Li, Jiakui; Chamba, Yangzom

2016-01-01

Toxocara vitulorum has been rarely reported in yaks at high altitudes and remote areas of Sichuan Province of Tibetan Plateau of China. The current study was designed to investigate the prevalence, associated risk factors, and phylogenetic characteristics of T. vitulorum in yak calves on the Qinghai Tibetan plateau. Fecal samples were collected from 891 yak calves and were examined for the presence of T. vitulorum eggs by the McMaster technique. A multivariable logistic regression model was employed to explore variables potentially associated with exposure to T. vitulorum infection. T. vitulorum specimens were collected from the feces of yaks in Hongyuan of Sichuan Province, China. DNA was extracted from ascaris. After PCR amplification, the sequencing of ND1 gene was carried out and phylogenetic analyses was performed by MEGA 6.0 software. The results showed that 64 (20.1%; 95% CI 15.8–24.9%), 75 (17.2; 13.8–21.1), 29 (40.9; 29.3–53.2), and 5 (7.6; 2.5–16.8) yak calves were detected out to excrete T. vitulorum eggs in yak calve feces in Qinghai, Tibet, Sichuan, and Gansu, respectively. The present study revealed that high infection and mortality by T. vitulorum is wildly spread on the Qinghai Tibetan plateau, China by fecal examination. Geographical origin, ages, and fecal consistencies are the risk factors associated with T. vitulorum prevalence by logistic regression analysis. Molecular detection and phylogenetic analysis of ND1 gene of T. vitulorum indicated that T. vitulorum in the yak calves on the Qinghai Tibetan plateau are homologous to preveiously studies reported. PMID:27853122

Late Holocene subalpine lake sediments record a multi-proxy shift to increased aridity at 3.65 kyr BP, following a millennial-scale neopluvial interval in the Lake Tahoe watershed and western Great Basin, USA

NASA Astrophysics Data System (ADS)

Noble, Paula; Zimmerman, Susan; Ball, Ian; Adams, Kenneth; Maloney, Jillian; Smith, Shane

2016-04-01

lake-level rise beginning at some point after 5 kcal yr BP and reaching a highstand of about 1186 m between 3.8 - 4.1 kcal yr BP (Briggs et al., 2005), but new OSL ages on Holocene shorelines are pending. In the Walker, Mono, and Owens lake basins, the neopluvial shorelines represent the highest late Holocene shorelines (Stine, 1990; Adams et al., 2014). Collectively, these studies indicate that the neopluvial and subsequent aridification intervals preserved in Fallen Leaf Lake sediments were at least regional in scale, affecting the watersheds in the northern Sierra Nevada-western Great Basin

Changes of glacier, glacier-fed rivers and lakes in Altai Tavan Bogd National Park, Western Mongolia, based on multispectral satellite data from 1990 to 2017

NASA Astrophysics Data System (ADS)

Batsaikhan, B.; Lkhamjav, O.; Batsaikhan, N.

2017-12-01

Impacts on glaciers and water resource management have been altering through climate changes in Mongolia territory characterized by dry and semi-arid climate with low precipitation. Melting glaciers are early indicators of climate change unlike the response of the forests which is slower and takes place over a long period of time. Mountain glaciers are important environmental components of local, regional, and global hydrological cycles. The study calculates an overview of changes for glacier, glacier-fed rivers and lakes in Altai Tavan Bogd mountain, the Western Mongolia, based on the indexes of multispectral data and the methods typically applied in glacier studies. Were utilized an integrated approach of Normalized Difference Snow Index (NDSI) and Normalized Difference Water Index (NDWI) to combine Landsat, MODIS imagery and digital elevation model, to identify glacier cover are and quantify water storage change in lakes, and compared that with and climate parameters including precipitation, land surface temperature, evaporation, moisture. Our results show that melts of glacier at the study area has contributed to significantly increase of water storage of lakes in valley of The Altai Tavan Bogd mountain. There is hydrologic connection that lake basin is directly fed by glacier meltwater.

Sediment Transforms Lake Michigan

NASA Image and Video Library

2011-01-11

NASA image acquired December 17, 2010 In mid-December 2010, suspended sediments transformed the southern end of Lake Michigan. Ranging in color from brown to green, the sediment filled the surface waters along the southern coastline and formed a long, curving tendril extending toward the middle of the lake. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured these natural-color images on December 17, 2010 (top), and December 10, 2010 (bottom). Such sediment clouds are not uncommon in Lake Michigan, where winds influence lake circulation patterns. A scientificpaper published in 2007 described a model of the circulation, noting that while the suspended particles mostly arise from lake-bottom sediments along the western shoreline, they tend to accumulate on the eastern side. When northerly winds blow, two circulation gyres, rotating in opposite directions, transport sediment along the southern shoreline. As the northerly winds die down, the counterclockwise gyre predominates, and the smaller, clockwise gyre dissipates. Clear water—an apparent remnant of the small clockwise gyre—continues to interrupt the sediment plume. George Leshkevich, a researcher with the U.S. National Oceanic and Atmospheric Administration, explains that the wind-driven gyres erode lacustrine clay (very fine lakebed sediment) on the western shore before transporting it, along with re-suspended lake sediments, to the eastern shore. On the eastern side, the gyre encounters a shoreline bulge that pushes it toward the lake’s central southern basin, where it deposits the sediments. The sediment plume on December 17 followed a windy weather front in the region on December 16. NASA image courtesy MODIS Rapid Response Team at NASA GSFC. Caption by Michon Scott. Instrument: Aqua - MODIS NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard

Lessons Learned from Stakeholder-Driven Modeling in the Western Lake Erie Basin

NASA Astrophysics Data System (ADS)

Muenich, R. L.; Read, J.; Vaccaro, L.; Kalcic, M. M.; Scavia, D.

2017-12-01

Lake Erie's history includes a great environmental success story. Recognizing the impact of high phosphorus loads from point sources, the United States and Canada 1972 Great Lakes Water Quality Agreement set load reduction targets to reduce algae blooms and hypoxia. The Lake responded quickly to those reductions and it was declared a success. However, since the mid-1990s, Lake Erie's algal blooms and hypoxia have returned, and this time with a dominant algae species that produces toxins. Return of the algal blooms and hypoxia is again driven by phosphorus loads, but this time a major source is the agriculturally-dominated Maumee River watershed that covers NW Ohio, NE Indiana, and SE Michigan, and the hypoxic extent has been shown to be driven by Maumee River loads plus those from the bi-national and multiple land-use St. Clair - Detroit River system. Stakeholders in the Lake Erie watershed have a long history of engagement with environmental policy, including modeling and monitoring efforts. This talk will focus on the application of interdisciplinary, stakeholder-driven modeling efforts aimed at understanding the primary phosphorus sources and potential pathways to reduce these sources and the resulting algal blooms and hypoxia in Lake Erie. We will discuss the challenges, such as engaging users with different goals, benefits to modeling, such as improvements in modeling data, and new research questions emerging from these modeling efforts that are driven by end-user needs.

[Analysis on the results of etiology and serology of plague in Qinghai province from 2001 to 2010].

PubMed

Yang, Yonghai; Wang, Mei; Zhao, Xiaolong; Zhao, Zhongzhi; Zhang, Aiping; Wei, Rongjie; Wei, Baiqing; Wang, Zuyun

2014-02-01

To analyze the results of etiology and serology of plague among human and infected animals in Qinghai province from 2001 to 2010. Thirty-seven cases of human infected with plague, 53 541 different animal samples, 5 685 sets of vector insects flea and 49 039 different animal serum samples were obtained between 2001 and 2010. A total of 7 811 samples of serum from healthy farmers and herdsmen in 14 counties in Qinghai from 2005 to 2007 were collected. Yersinia pestis (Y. pestis) were detected in visceral and secretions from human, infected animals and vector insects, respectively. Plague antigen was detected by reverse indirect hemagglutination assay (RIHA) in those samples. Indirect hemagglutination assay (IHA) was used to test plague FI antibody in serum of human and infected animals. 37 human plague cases were confirmed, 21 strains of plague Y. pestis were isolated from human cases and 14 positive were detected out. 133 of 7 811 samples of human serum were IHA positive, with the positive rate at 1.7%. A total of 146 strains of plague were isolated from infected animals and vector insects, 99 out of which were from infected animals, with a ratio of Marmota himalayan at 72.7% (72/99) and the other 47 were from vector insects, with a ratio of callopsylla solaris at 68.1% (32/47). The number of IHA and PIHA positive were 300 and 10, respectively. A total of 3 animals and 3 insects species were identified as new epidemic hosts for plague. The natural plague focus of Microtus fuscus was discovered and confirmed and coexisted with natural focus of Marmota himalayan in Chengduo county, Yushu prefecture. The epidemic situation of plague is distributed mainly in Haixi, Yushu and Hainan prefectures. From 2001 to 2010, animal infected with plague was detected in successive years and human plague was very common in Qinghai. New infected animals and vector insects species and new epidemic areas were confirmed, hence the trend of plague prevalence for humans and animals is very

Key Role of Alphaproteobacteria and Cyanobacteria in the Formation of Stromatolites of Lake Dziani Dzaha (Mayotte, Western Indian Ocean).

PubMed

Gérard, Emmanuelle; De Goeyse, Siham; Hugoni, Mylène; Agogué, Hélène; Richard, Laurent; Milesi, Vincent; Guyot, François; Lecourt, Léna; Borensztajn, Stephan; Joseph, Marie-Béatrice; Leclerc, Thomas; Sarazin, Gérard; Jézéquel, Didier; Leboulanger, Christophe; Ader, Magali

2018-01-01

Lake Dziani Dzaha is a thalassohaline tropical crater lake located on the "Petite Terre" Island of Mayotte (Comoros archipelago, Western Indian Ocean). Stromatolites are actively growing in the shallow waters of the lake shores. These stromatolites are mainly composed of aragonite with lesser proportions of hydromagnesite, calcite, dolomite, and phyllosilicates. They are morphologically and texturally diverse ranging from tabular covered by a cauliflower-like crust to columnar ones with a smooth surface. High-throughput sequencing of bacterial and archaeal 16S rRNA genes combined with confocal laser scanning microscopy (CLSM) analysis revealed that the microbial composition of the mats associated with the stromatolites was clearly distinct from that of the Arthrospira -dominated lake water. Unicellular-colonial Cyanobacteria belonging to the Xenococcus genus of the Pleurocapsales order were detected in the cauliflower crust mats, whereas filamentous Cyanobacteria belonging to the Leptolyngbya genus were found in the smooth surface mats. Observations using CLSM, scanning electron microscopy (SEM) and Raman spectroscopy indicated that the cauliflower texture consists of laminations of aragonite, magnesium-silicate phase and hydromagnesite. The associated microbial mat, as confirmed by laser microdissection and whole-genome amplification (WGA), is composed of Pleurocapsales coated by abundant filamentous and coccoid Alphaproteobacteria. These phototrophic Alphaproteobacteria promote the precipitation of aragonite in which they become incrusted. In contrast, the Pleurocapsales are not calcifying but instead accumulate silicon and magnesium in their sheaths, which may be responsible for the formation of the Mg-silicate phase found in the cauliflower crust. We therefore propose that Pleurocapsales and Alphaproteobacteria are involved in the formation of two distinct mineral phases present in the cauliflower texture: Mg-silicate and aragonite, respectively. These results

Anatomy of the Midcontinent Rift beneath Lake Superior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, M.D.; McGinnis, L.D.; Ervin, C.P.

1994-09-01

The structure and geometry of the 1.1-b.y.-old Midcontinent Rift system under Lake Superior is interpreted from 20 seismic reflection profiles recorded during the early and mid-1980s. The seismic data reveal that rift basins under Lake Superior are variable in depth and are partially filled with Keweenawan age sediments to depths of 7 km or more and volcanic flows to depths of 36 km. These rift basins form a continuous and sinuous feature that widens in the Allouez Basin and Marquette Basin in the western and central lake and narrows between White Ridge and the Porcupine Mountains. The rift basin bendsmore » southeast around the Keweenaw Peninsula, widens to about 100 km as it extends into the eastern half of Lake Superior, and exists the lake with its axis in the vicinity of Au Sable Point in Pictured Rocks National Lake Shore, about 50 km northeast of Munising, Michigan. The axis of the rift may exit the western end of the lake near Chequamegon Bay in Wisconsin. However, lack of data in that area limits interpretation at this time. Prior to late-stage reverse-faulting, a continuous basin of more uniform thickness was present beneath the lake. Crustal extension during rifting of approximately 50 km was followed by plate convergence and crustal shortening of approximately 30 km, with the major component of thrust from the southeast. Crustal shortening occurred after development of rift grabens and their filling with lava flows, but before deposition of the final sag basin sediments. Integration of information obtained from outcrops with data reported here indicates that the Lake Superior section of the rift is associated with as many as three major boundary faults.« less

Geothermal activity at continental rift Citala, Western Mexico, where Lake Chapala is emplaced: past and present

NASA Astrophysics Data System (ADS)

Zárate-del Valle, P. F.

2003-04-01

Lake Chapala is a tectonic lake developed on a continental rift named Citala (CRC) which belongs to a tectonically active zone in Western Mexico: the so-called Jalisco continental triple junction. Fossil sinter deposit, thermal spring, hydrothermal (hy) petroleum manifestation and hy alteration halo characterized the Lake Chapala basin. On the SE shore, outcrops a carbonate deposit named ``La Calera" (LC) which consists of a carbonate fossil sinter that measures 2 km in E-W direction and 600 m in N-S direction and overlays andesitic rock. With a thickness of approximately 5 m and a roughly horizontal attitude, the LC is characterized by a two-fold structure: when massive, it is colored in yellow brownish and grey and elsewhere it shows a pseudo-brecciated structure and when banded, yellow and dark millimetre alternated bands can be seen. The LC is marked by vuggy porosity and silica (quartz and chalcedony) vein lets. Under microscope a pseudo-micritic texture is observed; vugs coated by iron oxides, are filled with calcite, and/or quartz, chalcedony and clay minerals. Six samples of LC were analysed (LODC-UParis VI) for their stable isotopes (δ18O and δ13C): From δ13C{PDB} values we have two sets of data: -8.03 to -8.69 ppm that means a no contribution of organic carbon (oc) and -0.35 to -0.75 ppm meaning an important contribution of oc; from δ18O{PDB} values: -8.5 to -10.27 ppm we deduced a deposit in meteoric water with a temperature deposition higher than the surface. The CRC is characterized also by the presence of hydrothermal petroleum (hp): Inside the Chapala and ˜2 km from SE shore (Los Arcos) there are some small spots made of hp which look like islands (<3-4 m^2) linked to the bottom of the lake which consist of solid bitumen. Thermal springs (ths) occur both inside and outside the lake Chapala: the water in out-shore ths is of carbonate type (69^oC; ˜ 240 mg L-1 [HCO_3]^-; with one exception: the ths at the San Juan Cosalá spa (N shore), which is

Simulation of lake ice and its effect on the late-Pleistocene evaporation rate of Lake Lahontan

USGS Publications Warehouse

Hostetler, S.W.

1991-01-01

A model of lake ice was coupled with a model of lake temperature and evaporation to assess the possible effect of ice cover on the late-Pleistocene evaporation rate of Lake Lahontan. The simulations were done using a data set based on proxy temperature indicators and features of the simulated late-Pleistocene atmospheric circulation over western North America. When a data set based on a mean-annual air temperature of 3?? C (7?? C colder than present) and reduced solar radiation from jet-stream induced cloud cover was used as input to the model, ice cover lasting ??? 4 months was simulated. Simulated evaporation rates (490-527 mm a-1) were ??? 60% lower than the present-day evaporation rate (1300 mm a-1) of Pyramid Lake. With this reduced rate of evaporation, water inputs similar to the 1983 historical maxima that occurred in the Lahontan basin would have been sufficient to maintain the 13.5 ka BP high stand of Lake Lahontan. ?? 1991 Springer-Verlag.

Population dynamics and evaluation of alternative management strategies for nonnative Lake Trout in Priest Lake, Idaho

USGS Publications Warehouse

Ng, Elizabeth L.; Fredericks, Jim P.; Quist, Michael C.

2016-01-01

Lake Trout Salvelinus namaycush have been introduced widely throughout the western USA to enhance recreational fisheries, but high predatory demand can create challenges for management of yield and trophy fisheries alike. Lake Trout were introduced to Priest Lake, Idaho, during the 1920s, but few fishery-independent data are available to guide current or future management actions. We collected fishery-independent data to describe population dynamics and evaluate potential management scenarios using an age-structured population model. Lake Trout in Priest Lake were characterized by fast growth at young ages, which resulted in young age at maturity. However, adult growth rates and body condition were lower than for other Lake Trout populations. High rates of skipped spawning (>50%) were also observed. Model projections indicated that the population was growing (λ = 1.03). Eradication could be achieved by increasing annual mortality to 0.32, approximately twice the current rate. A protected slot length limit could increase population length-structure, but few fish grew fast enough to exit the slot. In contrast, a juvenile removal scenario targeting age-2 to age-5 Lake Trout maintained short-term harvest of trophy-length individuals while reducing overall population abundance.

Environmental setting of fixed sites in the western Lake Michigan drainages, Michigan and Wisconsin

USGS Publications Warehouse

Sullivan, D.J.; Peterson, E.M.; Richards, K.D.

1995-01-01

This report describes selected environmental- setting features for 11 fixed surface-water sites in the Western Lake Michigan Drainages study unit of the National Water-Quality Assessment Pro- gram. The study unit, which includes 10 major river systems draining to Lake Michigan, is bounded on the south by the Illinois State line and extends north to about 31 miles north of Escanaba, Mich. The fixed sites are on the following streams: Peshekee River, Popple River, Menominee River, Pensaukee River, Duck Creek, Tomorrow River, East River, Fox River, North Branch Milwaukee River, Lincoln Creek, and Milwaukee River. Drainage basins above these sites receive runoff from land uses and land covers, bedrock types, and surficial deposits representative of the main types of each of these characteristics in the study unit. Data types collected at the fixed sites include water chemistry; organic compounds and trace elements in streambed sediment and biological tissues; algal, benthic-invertebrate, and fish communities; and aquatic habitat. Field measurements include water temperature, pH, specific conductance, alkalinity, and dissolved oxygen. Results of water- quality field measurements indicate little variation in temperature among the fixed sites. Specific conductance and alkalinity were generally higher at sites underlain by carbonate bedrock than at sites underlain by igneous/metamorphic bedrock. Differences in pH among the fixed sites were less than those for specific conductance and alkalinity, but pH seemed to increase slightly from north to south. Dissolved-oxygen concentration varied more at agricultural sites than at forested and urban sites, perhaps because of higher nutrient inputs at agricultural sites. The information included in this report has been assembled as reference material for ongoing studies at the fixed sites.

Integrated assessment on the vulnerability of animal husbandry to snow disasters under climate change in the Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wei, Yanqiang; Wang, Shijin; Fang, Yiping; Nawaz, Zain

2017-10-01

Animal husbandry is a dominant and traditional source of livelihood and income in the Qinghai-Tibetan Plateau. The Qinghai-Tibetan Plateau is the third largest snow covered area in China and is one of the main snow disaster regions in the world. It is thus imperative to urgently address the issue of vulnerability of the animal husbandry sector to snow disasters for disaster mitigation and adaptation under growing risk of these disasters as a result of future climate change. However, there is very few literature reported on the vulnerability of animal husbandry in the Qinghai-Tibetan Plateau. This assessment aims at identifying vulnerability of animal husbandry at spatial scale and to identify the reasons for vulnerability for adaptive planning and disaster mitigation. First, historical snow disaster characteristics have been analyzed and used for the spatial weight for vulnerability assessment. Second, indicator-based vulnerability assessment model and indicator system have been established. We combined risk of snow hazard, sensitivity of livestock to disaster, physical exposure to disaster, and community capacity to adapt to snow disaster in an integrated vulnerability index. Lastly, vulnerability of animal husbandry to snow disaster on the Qinghai-Tibetan Plateau has been evaluated. Results indicate that high vulnerabilities are mainly concentrated in the eastern and central plateau and that vulnerability decreases gradually from the east to the west. Due to global warming, the vulnerability trend has eased to some extent during the last few decades. High livestock density exposure to blizzard-prone regions and shortages of livestock barn and forage are the main reasons of high vulnerability. The conclusion emphasizes the important role of the local government and community to help local pastoralists for reducing vulnerability to snow disaster and frozen hazard. The approaches presented in this paper can be used for snow disaster mitigation, resilience

Macrophyte succession in Swedish lakes caused by deposition of airborne acid substances

Treesearch

Olle Grahn

1976-01-01

Recurrent biological investigations have been made in six lakes in two areas in western Sweden. It has been found that the supply of acid substances induces long-term biological perturbations at all trophic levels in the lake ecosystem. Among these changes, the sphagnum expansion is believed to strongly affect the dynamics in the lake. A quantification of the Sphagnum...

Western Mountain Initiative - Background

Science.gov Websites

, and degraded water quality in mountain lakes and streams. In each case, ecosystem thresholds were dynamics; and the consequences of an altered water cycle for terrestrial and aquatic ecosystems and . Third, Western mountain ecosystems are important to society, providing water, wood products, carbon

Lake-sediment evidence for the date of deglaciation of the Hidden Lake area, Kenai Peninsula, Alaska

NASA Astrophysics Data System (ADS)

Rymer, Michael J.; Sims, John D.

1982-06-01

An abrupt environmental change is reflected in a core from Hidden Lake, Alaska, by differences in sediment type, chlorite crystallinity, and content of organic carbon and water of the sediments. This abrupt change in the sedimentary record occurred about 14,500 14C yr ago and probably marks the time of recession of the glacier from the Hidden Lake drainage basin. Deglaciation of the area was then underway, and rock flour was being deposited in the lake. After recession of the glacier from the Hidden Lake drainage basin, rock flour was no longer introduced, and organic-matter content of the sediment increased. By the dating of these changes in sediment type, we show that retreat of glaciers in this area took place significantly earlier than previously estimated; this agrees with the timing of retreat of alpine glaciers elsewhere in western North America.

Transient groundwater-lake interactions in a continental rift: Sea of Galilee, Israel

USGS Publications Warehouse

Hurwitz, S.; Stanislavsky, E.; Lyakhovsky, V.; Gvirtzman, H.

2000-01-01

The Sea of Galilee, located in the northern part of the Dead Sea rift, is currently an intermediate fresh-water lake. It is postulated that during a short highstand phase of former Lake Lisan in the late Pleistocene, saline water percolated into the subsurface. Since its recession from the Kinarot basin and the instantaneous formation of the fresh-water lake (the Sea of Galilee), the previously intruded brine has been flushed backward toward the lake. Numerical simulations solving the coupled equations of fluid flow and of solute and heat transport are applied to examine the feasibility of this hypothesis. A sensitivity analysis shows that the major parameters controlling basin hydrodynamics are lake-water salinity, aquifer permeability, and aquifer anisotropy. Results show that a highstand period of 3000 yr in Lake Lisan was sufficient for saline water to percolate deep into the subsurface. Because of different aquifer permeabilities on both sides of the rift, brine percolated into a aquifers on the western margin, whereas percolation was negligible on the eastern side. In the simulation, after the occupation of the basin by the Sea of Galilee, the invading saline water was leached backward by a topography-driven flow. It is suggested that the percolating brine on the western side reacted with limestone at depth to form epigenetic dolomite at elevated temperatures. Therefore, groundwater discharging along the western shores of the Sea of Galilee has a higher calcium to magnesium ratio than groundwater on the eastern side.

Abrupt lake-level changes in the Rocky Mountains and surrounding regions since the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Shuman, B. N.; Serravezza, M.

2016-12-01

The paleohydrologic record of western North America since the last glacial maximum reveals a wide range of hydroclimatic variability and distinctive patterns associated with abrupt climate changes. To evaluate the sequence of abrupt hydroclimatic shifts and centennial-to-millennial hydrologic variability in western North America over the past 17 ka, we reconstruct lake-level histories from two high-elevation lakes in the Beartooth and Bighorn Mountains. The lakes represent the headwaters of the Missouri River drainage in northern Wyoming, but also have the potential to capture regional hydroclimate variability that links the northern Rocky Mountains to the mid-continent, Pacific Northwest, and the Great Basin. We first discuss the stratigraphic record of lake-level changes in small mid-latitude lakes and then use ground-penetrating radar (GPR) and sediment cores to track the elevations of shoreline sediments within the lakes through time. We compare the stratigraphies to the records from four other lakes in Wyoming and Colorado, and find widespread evidence for a Terminal Pleistocene Drought from 15-11 ka, an early Holocene humid period from 11-8 ka, and a period of severe mid-Holocene aridity from 8-5.7 ka. The northern Wyoming lakes also provide evidence of high levels before ca. 15 ka, including rapid hydroclimatic changes at ca. 16.8 ka during Heinrich Event 1. We place the changes in a broad context by summarizing and mapping water-level changes from 107 additional, previously studied lakes. Important patterns include 1) extensive drying across the western U.S. after 15 ka; 2) coherent sub-regional differences during the Younger Dryas and Pleistocene-Holocene transition; 3) a north-south contrast from 9-6 ka consistent with a northward shift in storm tracks as the influence of the Laurentide Ice Sheet diminished; and 4) rapid increases in effective moisture across much of western North America from 6-4 ka.

CHAPHOLO (scientific drilling project): Paleolimnological Evaluation of Lake Chapala, western Mexico, During Holocene (CONACYT grant: CB2011-168685)

NASA Astrophysics Data System (ADS)

Zarate, P. F.; Fritz, S. C.; Ramirez Sanchez, U.; Gomez Salazar, S.; Ceja Andrade, I.; Priyadarsi Debajyoti, R.; Brenner, M.

2012-12-01

CHAPHOLO ( CHAP: Chapala; HOLO: Holocene) has as goal to evaluate paleoenvironmental variations recorded in the sediment of neotectonic Lake Chapala (LCH), western Mexico (20°15.129'N, 103° 02.996'W). The lake lies about 1524 m asl. LCH is the largest lake in Mexico (1,100 kmyr2), but is shallow (zmax = 7.20 m). It is located in a basin belonging to the Citala Rift, the east-west branch of three continental rifts that join to form the so-called Jalisco triple junction. Our working hypothesis is that recent (Holocene) paleolimnological changes in LCH were caused by major climate variations and by minor regional/local processes (e.g. volcanism). We will drill a 40m long core from the lake depocenter, with the objective of recovering a full Holocene record, and likely more, assuming a mean sedimentation rate of 2 mm yr-1. Core chronology will be established using AMS 14C and 210Pb techniques and climate inferences will be made using geochemical, geophysical and micropaleontological proxies. Particularly, we pretend to identify the six "short" fluctuations of climate that characterized the Holocene (Mayewski et al., 2004) and the identification of Mediewal Warm Period and the droughts affected the mayan culture (Hodell et al., 1995). We will verify the application of Ti as a proxy to rainfall (Metcalfe et al., 2010). During the last 10,000 the fact about the dissolution of diatom in LCH sediments must be evaluated (Ryves et al., 2009). The working group is multidisciplinary (Geochemistry, Micropaleontology, Paleolimnology, Geophysics) and involves multiple institutions (Guadalajara University, Mexican National University-UNAM, University of Florida, University of Nebraska-Lincoln). CHAPHOLO is supported by funds from the Mexican government and from the Guadalajara University. The theme of CHAPHOLO is consistent with global environmental programs such as PAGES and CLIVAR. This project will be developed in stages over three years.

Deployment of deer-resistant western redcedar (Thuja plicata)

Treesearch

John Russell

2008-01-01

Protecting planted western redcedar (Thuja plicata) seedlings from deer browse in the Pacific Northwest and British Columbia is estimated to cost up to CAN$ 25 million annually. Recent studies linking deer browse and needle monoterpenes has resulted in the initiation of a breeding program for deer-resistant western redcedar at Cowichan Lake Research...

Predation on walleye eggs by fish on reefs in western Lake Erie

USGS Publications Warehouse

Roseman, E.F.; Taylor, W.W.; Hayes, D.B.; Jones, A.L.; Francis, J.T.

2006-01-01

We examined diets of fishes from gillnet and egg pump collections conducted on reefs in western Lake Erie during walleye (Sander vitreus) egg incubation periods from 1994–1999 and 2004 to assess incidence of walleye eggs in fish diets. We collected no potential egg predators in samples taken in 1994 but from 1995–1999 and in 2004 we caught 22 different species of fish on reefs in addition to spawning walleye. In most years, white perch (Morone americana) stomachs contained more walleye eggs than any other species on the reefs averaging 253 eggs per stomach. We also found lower numbers of walleye eggs in the stomachs of channel catfish (Ictalurus punctatus; 53 eggs/stomach), johnny darter (Etheostoma nigrum; 2 eggs/stomach), logperch (Percina caprodes; 10 eggs/stomach), quillback (Carpiodes cyprinus; 184 eggs/stomach), rock bass (Ambloplites rupestris; 3 eggs/stomach), round goby (Neogobius melanostomus; 4 eggs/stomach), sculpin (Cottidae; 21 eggs/stomach), silver chub (Macrhybopsis storeriana; 3 eggs/stomach), spottail shiner (Notropis hudsonius; 14 eggs/stomach), trout-perch (Percopsis omiscomaycus; 30 eggs/stomach), white sucker (Catastomus commersonii; 20 eggs/stomach), and yellow perch (Perca flavescens; 181 eggs/stomach). Similar to other studies of predation on walleye eggs, our results indicate that prolonged incubation periods increase the potential for egg loss due to predation.

The Paleolimnological Record of the North Atlantic Oscillation: Magnetic Properties and Diatom Counts from Hemlock and Conesus Lakes, Western New York State

NASA Astrophysics Data System (ADS)

Chaisson, W. P.; Arnold, M. R.; Cottrell, R. D.

2002-05-01

Between 1900 and 1930 CE when the NAO index showed large amplitude positive excursions, but the AO index varied at very small amplitudes, drought conditions frequently prevailed in western New York state according the Palmer Drought Index (PDI). Since 1970, when both the NAO and the AO indices show large and progressively increasing positive excursions, the PDI has been generally positive, indicating moisture surpluses in the region. Magnetic properties, including coercivity of remanence, have been measured and the diatoms have been enumerated in sediments from two gravity cores collected from Hemlock and Conesus Lakes. The sediments date from ~1875 CE in the Hemlock core and ~1923 CE in the Conesus core. Variations in magnetic grain-size are interpreted from the coercivity of remanence, with lower coercivity of remanence associated with large grain size. The primary productivity of lakes is interpreted from the Lake Trophic Status Index (LTSI), which is calculated based on known ecologies of several diatom species. In both lakes we find that larger magnetic grain size is associated with greater productivity in the lakes. In the Hemlock core, through the interval corresponding to 1913-1943 coercivity of remanence values declined to 281-259 Oersteds, from late 19th century values that were >350 Oersteds. The bottom of the Conesus core (1923-1938 CE) has the lowest coercivity of remanance values in the record (309-317 Oersteds). LTSI values in the Hemlock samples increase as remanence of coercivity values decline between 1888 and 1920 CE. This reflects an increase in the abundance of the mesoeutrophic Tabellaria fenestrata during this interval. In the Conesus samples the agreement between coercivity of remanence and LTSI is quite close. The range of variation in both LTSI and magnetic grain size is smaller in Conesus than in Hemlock Lake. The diatom assemblage is also quite different in Conesus, dominated by eutrophic Aulacosiera granulata, which are rare or absent

Starch granule-associated proteins of hull-less barley (Hordeum vulgare L.) from the Qinghai-Tibet Plateau in China.

PubMed

Wang, Chun-Ping; Pan, Zhi-Fen; Nima, Zha-Xi; Tang, Ya-Wei; Cai, Peng; Liang, Jun-Jun; Deng, Guang-Bing; Long, Hai; Yu, Mao-Qun

2011-03-15

The starch granule-associated proteins (SGAPs) are the minor components of the starch granules and a majority of them are believed to be starch biosynthetic enzymes. The Qinghai-Tibet Plateau in China, one of the centres of origin of cultivated barley, is abundant in hull-less barley resources which exhibit high polymorphism in SGAPs. The SGAPs of hull-less barley from Qinghai-Tibet Plateau were analysed by one-dimensional (1-D) SDS-PAGE, 2-D PAGE and ESI-Q-TOF MS/MS. In the 1-D SDS-PAGE gel, four proteins including a 80 kDa starch synthase, actin, actin 4 and ATP synthase β-subunit were identified as novel SGAPs. A total of six different bands were identified as starch granule-bound starch synthase I (GBSSI) and the segregation of the novel GBSSI bands in F(1) and F(2) seeds derived from yf127 × yf70 was in accordance with Mendel's law. In the 2-D PAGE gel, 92 spots were identified as 42 protein species which could be classified into 15 functional groups. Thirteen protein species were identified as SGAPs for the first time and multiple spots were identified as GBSSI. This study revealed novel SGAPs in hull-less barley from the Qinghai-Tibet Plateau in China and these will be significant in further studies of starch biosynthesis in barley. Copyright © 2011 Society of Chemical Industry.

Effect of degradation intensity on grassland ecosystem services in the alpine region of Qinghai-Tibetan Plateau, China.

PubMed

Wen, Lu; Dong, Shikui; Li, Yuanyuan; Li, Xiaoyan; Shi, Jianjun; Wang, Yanlong; Liu, Demei; Ma, Yushou

2013-01-01

The deterioration of alpine grassland has great impact on ecosystem services in the alpine region of Qinghai-Tibetan Plateau. However, the effect of grassland degradation on ecosystem services and the consequence of grassland deterioration on economic loss still remains a mystery. So, in this study, we assessed four types of ecosystem services following the Millennium Ecosystem Assessment classification, along a degradation gradient. Five sites of alpine grassland at different levels of degradation were investigated in Guoluo Prefecture of Qinghai Province, China. The species composition, aboveground biomass, soil total organic carbon (TOC), and soil total nitrogen (TN) were tested to evaluate major ecological services of the alpine grassland. We estimated the value of primary production, carbon storage, nitrogen recycling, and plant diversity. The results show the ecosystem services of alpine grassland varied along the degradation gradient. The ecosystem services of degraded grassland (moderate, heavy and severe) were all significantly lower than non-degraded grassland. Interestingly, the lightly degraded grassland provided more economic benefit from carbon maintenance and nutrient sequestration compared to non-degraded. Due to the destruction of the alpine grassland, the economic loss associated with decrease of biomass in 2008 was $198/ha. Until 2008, the economic loss caused by carbon emissions and nitrogen loss on severely degraded grassland was up to $8 033/ha and $13 315/ha, respectively. Urgent actions are required to maintain or promote the ecosystem services of alpine grassland in the Qinghai-Tibetan Plateau.

Effect of Degradation Intensity on Grassland Ecosystem Services in the Alpine Region of Qinghai-Tibetan Plateau, China

PubMed Central

Wen, Lu; Dong, Shikui; Li, Yuanyuan; Li, Xiaoyan; Shi, Jianjun; Wang, Yanlong; Liu, Demei; Ma, Yushou

2013-01-01

The deterioration of alpine grassland has great impact on ecosystem services in the alpine region of Qinghai-Tibetan Plateau. However, the effect of grassland degradation on ecosystem services and the consequence of grassland deterioration on economic loss still remains a mystery. So, in this study, we assessed four types of ecosystem services following the Millennium Ecosystem Assessment classification, along a degradation gradient. Five sites of alpine grassland at different levels of degradation were investigated in Guoluo Prefecture of Qinghai Province, China. The species composition, aboveground biomass, soil total organic carbon (TOC), and soil total nitrogen (TN) were tested to evaluate major ecological services of the alpine grassland. We estimated the value of primary production, carbon storage, nitrogen recycling, and plant diversity. The results show the ecosystem services of alpine grassland varied along the degradation gradient. The ecosystem services of degraded grassland (moderate, heavy and severe) were all significantly lower than non-degraded grassland. Interestingly, the lightly degraded grassland provided more economic benefit from carbon maintenance and nutrient sequestration compared to non-degraded. Due to the destruction of the alpine grassland, the economic loss associated with decrease of biomass in 2008 was $198/ha. Until 2008, the economic loss caused by carbon emissions and nitrogen loss on severely degraded grassland was up to $8 033/ha and $13 315/ha, respectively. Urgent actions are required to maintain or promote the ecosystem services of alpine grassland in the Qinghai-Tibetan Plateau. PMID:23469278

Rapid radiation and dispersal out of the Qinghai-Tibetan Plateau of an alpine plant lineage Rhodiola (Crassulaceae).

PubMed

Zhang, Jian-Qiang; Meng, Shi-Yong; Allen, Geraldine A; Wen, Jun; Rao, Guang-Yuan

2014-08-01

Rhodiola L. (Crassulaceae) is a mid-sized plant genus consisting of about 70 species, with most species distributed on the Qinghai-Tibetan Plateau (QTP) and the adjacent areas, and several species in north-east Asia, Europe, and North America. This study explored the origin and diversification history of Rhodiola and tested the biogeographic relationships between the QTP and other regions of the Northern Hemisphere. We sequenced the nuclear ribosomal internal transcribed spacers and eight plastid DNA fragments representing 55 species of Rhodiola, and reconstructed phylogenetic relationships with maximum parsimony, maximum likelihood and Bayesian inference. Several instances of incongruence between the nuclear and the plastid data sets were revealed, which can best be explained by reticulate evolution. Species of Rhodiola and Pseudosedum form a well-supported clade sister to Phedimus. Dating analysis suggested that the origin and diversification times of this group are largely correlated with the extensive uplifts of the Qinghai-Tibetan Plateau. Ancestral state reconstruction supports the hypothesis that Rhodiola originated on the QTP, and then dispersed to other regions of the Northern Hemisphere. Our findings highlight the importance of the uplifts of the Qinghai-Tibetan Plateau in promoting species diversification and the possible role of reticulate evolution in the diversification process. Our results also suggest the biogeographic significance of QTP as the source area in alpine plant evolution in the Northern Hemisphere. Copyright © 2014 Elsevier Inc. All rights reserved.

Lake-levels, vegetation and climate in Central Asia during the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Amosov, Mikhail

2014-05-01

Central Asian region is bounded in the east corner of the Greater Khingan Range and the Loess Plateau, and to the west - the Caspian Sea. This representation of region boundaries is based on classical works of A.Humboldt and V.Obruchev. Three typical features of Central Asia nature are: climate aridity, extensive inland drainage basins with numerous lakes and mountain systems with developed glaciation. Nowadays the extensive data is accumulated about lake-levels during the Last Glacial Maximum (LGM) in Central Asia. Data compilation on 20 depressions, where lakes exist now or where they existed during LGM, shows that most of them had usually higher lake-level than at present time. This regularity could be mentioned for the biggest lakes (the Aral Sea, the Balkhash, the Ysyk-Kol etc.) and for small ones that located in the mountains (Tien Shan, Pamir and Tibet). All of these lake basins get the precipitation due to westerlies. On the other hand lakes, which are located in region's east rimland (Lake Qinghai and lakes in Inner Mongolia) and get the precipitation due to summer East Asian monsoons, do not comply with the proposed regularity. During LGM these lake-levels were lower than nowadays. Another exception is Lake Manas, its lake-level was also lowered. Lake Manas is situated at the bottom of Junggar Basin. There are many small rivers, which come from the ranges and suffer the violent fluctuation in the position of its lower channel. It is possible to assume that some of its runoff did not get to Lake Manas during LGM. Mentioned facts suggest that levels of the most Central Asian lakes were higher during LGM comparing to their current situation. However, at that period vegetation was more xerophytic than now. Pollen data confirm this information for Tibet, Pamir and Tien Shan. Climate aridization of Central Asia can be proved by data about the intensity of loess accumulation during LGM. This evidence received for the east part of region (the Loess Plateau) and

[Effects of human engineering activities on permafrost active layer and its environment in northern Qinghai-Tibetan plateau].

PubMed

Guo, Zhenggang; Wu, Qingbo; Niu, Fujun

2006-11-01

With disturbed and undisturbed belts during the construction of Qinghai-Tibet highway as test objectives, this paper studied the effects of human engineering activities on the permafrost ecosystem in northern Qinghai-Tibetan plateau. The results showed that the thickness of permafrost active layer was smaller in disturbed than in undisturbed belt, and decreased with increasing altitude in undisturbed belt while no definite pattern was observed in disturbed belt. Different vegetation types had different effects on the thickness of permafrost active layer, being decreased in the order of steppe > shrub > meadow. In the two belts, altitude was the main factor affecting the vertical distribution of soil moisture, but vegetation type was also an important affecting factor if the altitude was similar. Due to the human engineering activities, soil temperature in summer was lower in disturbed than in undisturbed belt.

Ecosystem Carbon Storage in Alpine Grassland on the Qinghai Plateau

PubMed Central

Liu, Shuli; Zhang, Fawei; Du, Yangong; Guo, Xiaowei; Lin, Li; Li, Yikang; Li, Qian; Cao, Guangmin

2016-01-01

The alpine grassland ecosystem can sequester a large quantity of carbon, yet its significance remains controversial owing to large uncertainties in the relative contributions of climate factors and grazing intensity. In this study we surveyed 115 sites to measure ecosystem carbon storage (both biomass and soil) in alpine grassland over the Qinghai Plateau during the peak growing season in 2011 and 2012. Our results revealed three key findings. (1) Total biomass carbon density ranged from 0.04 for alpine steppe to 2.80 kg C m-2 for alpine meadow. Median soil organic carbon (SOC) density was estimated to be 16.43 kg C m-2 in alpine grassland. Total ecosystem carbon density varied across sites and grassland types, from 1.95 to 28.56 kg C m-2. (2) Based on the median estimate, the total carbon storage of alpine grassland on the Qinghai Plateau was 5.14 Pg, of which 94% (4.85 Pg) was soil organic carbon. (3) Overall, we found that ecosystem carbon density was affected by both climate and grazing, but to different extents. Temperature and precipitation interaction significantly affected AGB carbon density in winter pasture, BGB carbon density in alpine meadow, and SOC density in alpine steppe. On the other hand, grazing intensity affected AGB carbon density in summer pasture, SOC density in alpine meadow and ecosystem carbon density in alpine grassland. Our results indicate that grazing intensity was the primary contributing factor controlling carbon storage at the sites tested and should be the primary consideration when accurately estimating the carbon storage in alpine grassland. PMID:27494253

Ecosystem Carbon Storage in Alpine Grassland on the Qinghai Plateau.

PubMed

Liu, Shuli; Zhang, Fawei; Du, Yangong; Guo, Xiaowei; Lin, Li; Li, Yikang; Li, Qian; Cao, Guangmin

2016-01-01

The alpine grassland ecosystem can sequester a large quantity of carbon, yet its significance remains controversial owing to large uncertainties in the relative contributions of climate factors and grazing intensity. In this study we surveyed 115 sites to measure ecosystem carbon storage (both biomass and soil) in alpine grassland over the Qinghai Plateau during the peak growing season in 2011 and 2012. Our results revealed three key findings. (1) Total biomass carbon density ranged from 0.04 for alpine steppe to 2.80 kg C m-2 for alpine meadow. Median soil organic carbon (SOC) density was estimated to be 16.43 kg C m-2 in alpine grassland. Total ecosystem carbon density varied across sites and grassland types, from 1.95 to 28.56 kg C m-2. (2) Based on the median estimate, the total carbon storage of alpine grassland on the Qinghai Plateau was 5.14 Pg, of which 94% (4.85 Pg) was soil organic carbon. (3) Overall, we found that ecosystem carbon density was affected by both climate and grazing, but to different extents. Temperature and precipitation interaction significantly affected AGB carbon density in winter pasture, BGB carbon density in alpine meadow, and SOC density in alpine steppe. On the other hand, grazing intensity affected AGB carbon density in summer pasture, SOC density in alpine meadow and ecosystem carbon density in alpine grassland. Our results indicate that grazing intensity was the primary contributing factor controlling carbon storage at the sites tested and should be the primary consideration when accurately estimating the carbon storage in alpine grassland.

Landsat-based trend analysis of lake dynamics across northern permafrost regions

USGS Publications Warehouse

Nitze, Ingmar; Grosse, Guido; Jones, Benjamin M.; Arp, Christopher D.; Ulrich, Mathias; Federov, Alexander; Veremeeva, Alexandra

2017-01-01

Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here we present, a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM,ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (-0.69%), Western Alaska (-2.82%), and Kolyma Lowland (-0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e. upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region.

Comparing Effects of Lake- and Watershed-Scale Influences on Communities of Aquatic Invertebrates in Shallow Lakes

PubMed Central

Hanson, Mark A.; Herwig, Brian R.; Zimmer, Kyle D.; Fieberg, John; Vaughn, Sean R.; Wright, Robert G.; Younk, Jerry A.

2012-01-01

Constraints on lake communities are complex and are usually studied by using limited combinations of variables derived from measurements within or adjacent to study waters. While informative, results often provide limited insight about magnitude of simultaneous influences operating at multiple scales, such as lake- vs. watershed-scale. To formulate comparisons of such contrasting influences, we explored factors controlling the abundance of predominant aquatic invertebrates in 75 shallow lakes in western Minnesota, USA. Using robust regression techniques, we modeled relative abundance of Amphipoda, small and large cladocera, Corixidae, aquatic Diptera, and an aggregate taxon that combined Ephemeroptera-Trichoptera-Odonata (ETO) in response to lake- and watershed-scale characteristics. Predictor variables included fish and submerged plant abundance, linear distance to the nearest wetland or lake, watershed size, and proportion of the watershed in agricultural production. Among-lake variability in invertebrate abundance was more often explained by lake-scale predictors than by variables based on watershed characteristics. For example, we identified significant associations between fish presence and community type and abundance of small and large cladocera, Amphipoda, Diptera, and ETO. Abundance of Amphipoda, Diptera, and Corixidae were also positively correlated with submerged plant abundance. We observed no associations between lake-watershed variables and abundance of our invertebrate taxa. Broadly, our results seem to indicate preeminence of lake-level influences on aquatic invertebrates in shallow lakes, but historical land-use legacies may mask important relationships. PMID:22970275

Evidence for millennial-scale climate change during marine isotope stages 2 and 3 at Little Lake, Western Oregon, U.S.A.

USGS Publications Warehouse

Grigg, L.D.; Whitlock, C.; Dean, W.E.

2001-01-01

Pollen and geochemical data from Little Lake, western Oregon, suggest several patterns of millennial-scale environmental change during marine isotope stage (MIS) 2 (14,100-27,600 cal yr B.P.) and the latter part of MIS 3 (27,600-42,500 cal yr B.P.). During MIS 3, a series of transitions between warm- and cold-adapted taxa indicate that temperatures oscillated by ca. 2??-4??C every 1000-3000 yr. Highs and lows in summer insolation during MIS 3 are generally associated with the warmest and coldest intervals. Warm periods at Little Lake correlate with warm sea-surface temperatures in the Santa Barbara Basin. Changes in the strength of the subtropical high and the jet stream may account for synchronous changes at the two sites. During MIS 2, shifts between mesic and xeric subalpine forests suggest changes in precipitation every 1000-3000 yr. Increases in Tsuga heterophylla pollen at 25,000 and 22,000 cal yr B.P. imply brief warmings. Minimum summer insolation and maximum global ice-volumes during MIS 2 correspond to cold and dry conditions. Fluctuations in precipitation at Little Lake do not correlate with changes in the Santa Barbara Basin and may be explained by variations in the strength of the glacial anticyclone and the position of the jet stream. ?? 2001 University of Washington.

Soil erosion risk assessment using interviews, empirical soil erosion modeling (RUSLE) and fallout radionuclides in a volcanic crater lake watershed subjected to land use change, western Uganda

NASA Astrophysics Data System (ADS)

De Crop, Wannes; Ryken, Nick; Tomma Okuonzia, Judith; Van Ranst, Eric; Baert, Geert; Boeckx, Pascal; Verschuren, Dirk; Verdoodt, Ann

2017-04-01

Population pressure results in conversion of natural vegetation to cropland within the western Ugandan crater lake watersheds. These watersheds however are particularly prone to soil degradation and erosion because of the high rainfall intensity and steep topography. Increased soil erosion losses expose the aquatic ecosystems to excessive nutrient loading. In this study, the Katinda crater lake watershed, which is already heavily impacted by agricultural land use, was selected for an explorative study on its (top)soil characteristics - given the general lack of data on soils within these watersheds - as well as an assessment of soil erosion risks. Using group discussions and structured interviews, the local land users' perceptions on land use, soil quality, soil erosion and lake ecology were compiled. Datasets on rainfall, topsoil characteristics, slope gradient and length, and land use were collected. Subsequently a RUSLE erosion model was run. Results from this empirical erosion modeling approach were validated against soil erosion estimates based on 137Cs measurements.

Lake-level increasing under the climate cryoaridization conditions during the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Amosov, Mikhail; Strelkov, Ivan

2017-04-01

A lake genesis and lake-level increasing during the Last Glacial Maximum (LGM) are the paramount issues in paleoclimatology. Investigating these problems reveals the regularities of lake development and figures out an arid territory conditions at the LGM stage. Pluvial theory is the most prevalent conception of lake formation during the LGM. This theory is based on a fact that the water bodies emerged and their level increased due to torrential rainfalls. In this study, it is paid attention to an alternative assumption of lake genesis at the LGM stage, which is called climate cryoaridization. In accordance with this hypothesis, the endorheic water basins had their level enlarged because of a simultaneous climate aridity and temperature decrease. In this research, a lake-level increasing in endorheic regions of Central Asia and South American Altiplano of the Andes is described. The lake investigation is related to its conditions during the LGM. The study also includes a lake catalogue clearly presenting the basin conditions at the LGM stage and nowadays. The data compilation partly consists of information from an earlier work of Mikhail Amosov, Lake-levels, Vegetation And Climate In Central Asia During The Last Glacial Maximum (EGU2014-3015). According to the investigation, a lake catalogue on 27 lakes showed that most of the water bodies had higher level. This feature could be mentioned for the biggest lakes of the Aral Sea, Lake Balkhash, Issyk-Kul etc. and for the small ones located in the mountains, such as Pamir, Tian-Shan and Tibet. Yet some lakes that are situated in Central Asian periphery (Lake Qinghai and lakes in Inner Mongolia) used to be lower than nowadays. Also, the lake-level increasing of Altiplano turned to be a significant feature during the LGM in accordance with the data of 5 lakes, such as Titicaca, Coipasa-Uyuni, Lejia, Miscanti and Santa-Maria. Most of the current endorheic basins at the LGM stage were filled with water due to abundant

Spatiotemporal pattern of vegetation remote sensing phenology and its response to climatic factors on the Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

An, S.; Chen, X.

2015-12-01

Based on the MODIS MCD12Q2 remote sensing phenology product, we analyzed spatiotemporal variations of vegetation green-up, maturity, senescence and brown-off dates, and their relation to spatiotemporal patterns of air temperature and precipitation on the Qinghai-Tibet Plateau (QTP). From 2001 to 2012, phenological time series at about 11.7%~15.1% pixels indicate significant linear trends (P<0.1) with strong spatial consistency. Namely, pixels with significant phenological advancement and growing season lengthening are mainly distributed in the middle and eastern parts of the QTP, while pixels with significant phenological delay and growing season shortening are mainly distributed in the western and southern parts as well as the eastern edge of the QTP. Similar spatial patterns for positive and negative linear trends of the minimum and maximum EVI, and the time-integrated EVI during the growing season were detected in the above two regions, respectively. With regard to climatic factors, mean annual temperature shows an increased trend over the QTP except for the eastern edge, whereas annual precipitation displays an increased trend in the middle and eastern parts but a decreased trend in the western and southern parts as well as the eastern edge of the QTP. These findings suggest that phenological advancement, growing season lengthening, and vegetation activity enhancement in the middle and eastern parts might be attributed to coincident temperature and precipitation increase. By contrast, phenological delay, growing season shortening, and vegetation activity reduction in the western and southern parts as well as the eastern edge might be caused by opposite changes of temperature and precipitation, and strong evaporation induced water shortage. Furthermore, a partial correlation analysis indicates that green-up, maturity, and brown-off dates were influenced by preceding temperature and precipitation, while senescence date was affected by preceding precipitation.

Geology and environments of subglacial Lake Vostok.

PubMed

Leitchenkov, German L; Antonov, Anton V; Luneov, Pavel I; Lipenkov, Vladimir Ya

2016-01-28

The reconstruction of the geological (tectonic) structure and environments of subglacial Lake Vostok is based on geophysical surveys and the study of mineral particles found in cores of accreted ice and frozen lake water (sampled after the lake was unsealed). Seismic reflection and refraction investigations conducted in the southern part of Lake Vostok show very thin (200-300 m) sedimentary cover overlying a crystalline basement. Most of this thin veneer is thought to have been deposited during temperate-glacial conditions in Oligocene to Middle Miocene time (ca 34-14 Ma). The composition of the lake-bottom sediments can be deduced from mineral inclusions found in cores of accreted ice. Inclusions are represented by soft aggregates consisting mainly of clay-mica minerals and micrometre-sized quartz grains. Some of these inclusions contain subangular to semi-rounded rock clasts (siltstones and sandstones) ranging from 0.3 to 8 mm in size. In total, 31 zircon grains have been identified in two rock clasts and dated using SHRIMP-II. The ages of the studied zircons range from 0.6 to 2.0 Ga with two distinct clusters between 0.8 and 1.15 Ga and between 1.6 and 1.8 Ga. Rock clasts obviously came from the western lake shore, which is thus composed of terrigenous strata with an age of not older than 600 Ma. The sedimentary nature of the western lake shore is also confirmed by seismic refraction data showing seismic velocities there of 5.4-5.5 km s(-1) at the bedrock surface. After Lake Vostok was unsealed, its water (frozen and sampled next season) was also studied with scanning electron microscopy and X-ray microprobe analysis. This study showed the existence of calcium carbonate and silica microparticles (10-20 μm across) in frozen water. © 2015 The Author(s).

Creep characteristics and process analyses of a thaw slump in the permafrost region of the Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Sun, Zhe; Wang, Yibo; Sun, Yan; Niu, Fujun; Li, Guoyu; Gao, Zeyong

2017-09-01

A thaw slump in the permafrost region of the Qinghai-Tibet Plateau was monitored to investigate typical characteristics of creep positions and processes in combination with soil property analyses. The results show that the thaw settlement exhibits a contraction effect in the horizontal direction because of uneven thaw settlement. Slope displacement of creep occurs only in the top 50 cm of the soil. The gravimetric water content, soil porosity, and soil temperature are higher near the thaw slump in thaw seasons compared with the undisturbed soil; however, the shear strength is lower. Melting ground ice releases thaw water that converges along the slope and forms an overland flow at the front part of the gentle slope area and a ponding depression at the slope bottom. The analyses of slope stability using the infinite slope model shows that the headwall of the slope is inevitably unstable and slides under saturated conditions, whereas the gentle slope area and slope bottom with slight creep displacement are relatively stable. The small retrogressive thaw slump is in an early development stage. With increasing degree of thaw settlement and rate of erosion, the headwall will become steeper and a thermokarst lake will form at the slope bottom.

Sources and deposition of polycyclic aromatic hydrocarbons to western US national parks

EPA Science Inventory

Seasonal snowpack, lichens, and lake sediment cores were collected from fourteen lake catchments in eight western U.S. National Parks and analyzed for sixteen polycyclic aromatic hydrocarbons (PAHs) to determine their current and historical deposition, as well as to identify thei...

Miocene woods from the Qaidam Basin on northern Qinghai-Tibet Plateau with implications for paleoenvironmental change

NASA Astrophysics Data System (ADS)

Cheng, Ye-Ming; Yang, Xiao-Nan

2016-02-01

The Qaidam Basin with the most complete Cenozoic sedimentary preservation in northern Qinghai-Tibet Plateau is a key area for studying uplift and environmental change of the plateau. Three types of woods, Ulmus (Ulmaceae), Leguminosae (?) (angiosperm) and Cupressaceae (gymnosperm) were recognized from the large-scale preservation of fossil woods in late Miocene Shang Youshashan Formation in northern Qaidam Basin on the Qinghai-Tibet Plateau. Both investigations of their Nearest Living Relatives (NLRs) and previous grassland mammal evidences suggest that there have been temperate deciduous broad-leaved forest and needle-leaved forest with grass in northern Qaidam Basin during the late Miocene in contrast to the desert vegetation found there nowadays. The presence of the ancient forest steppe further implies that the southern part of the plateau used to be adequately low, so that the Indian and East Asian monsoons could approach the northern area and to accommodate the vegetation in late Miocene.

Assessment of maternal anemia in rural Western China between 2001 and 2005: a two-level logistic regression approach

PubMed Central

2013-01-01

Background There are multiple adverse effects of anemia on human function, particularly on women. However, few researches are conducted on women anemia in rural Western China. This study mainly aims to investigate the levels and associated factors of maternal anemia between 2001 and 2005 in this region. Methods 6172 and 5372 mothers with children under three years old were selected from 8 provinces in 2001 and from 9 provinces in 2005 respectively in Western China by means of a multi-stage probability proportion to size sampling method (PPS). The blood samples were tested and related socio-demographic information was obtained through questionnaires. A two-level logistic regression model was employed to identify the determinants and provincial variations of women anemia in 2001 and 2005. Results The results indicated that the crude prevalence of women anemia in 2005 was higher than the rate in 2001(45.7% vs 33.6%). Based on the nationwide census data in 2000, the age-standardized prevalence of women anemia in the study were obtained as 38.0% in 2001 and 50.0% in 2005 respectively. Two-level logistic model analysis showed that compared to the average, women were more likely to be anemic in Guangxi and Qinghai in 2001 as well as in Chongqing and Qinghai in 2005; that women from Minority groups had higher odds of anemia in contrast with Han; that women with higher parity, longer breastfeeding duration and higher socioeconomic level had a lower rate of anemia, while age of women was positively associated with anemia. The positive correlation between women anemia and altitude was also observed. Conclusions The study demonstrated that the burden of maternal anemia in rural Western China increased considerably between 2001 and 2005. The Chinese government should conduct integrated interventions on anemia of mothers in this region. PMID:23597320

Age, growth, and maturity of the longnose sucker Catostomus catostomus, of western Lake Superior

USGS Publications Warehouse

Bailey, Merryll M.

1969-01-01

Studies of age, growth, and maturity were based on 1760 fish collected in western Lake Superior in 1964-65. The body:scale relation was curvilinear and the curve had an intercept of 1.65 inches on the length axis. The weight increased as the 2.85 power of the length. Some fish formed an annulus before May 18 in 1965; all had completed annuli by late September. Longnose suckers grew 3.6 inches the 1st year, reached 12 inches in the 6th year, and 18 inches in the 11th year. Fish from Pikes Bay grew faster than those from Gull Island Shoal. Over 6 years were required for weight to reach 1 lb and nearly 10 years to reach 2 lb. Minimum length at maturity was 10.5 inches for males and 11.5 inches for females. The youngest mature male belonged to age-group IV and the youngest mature female to age-group V. All males were mature at 14.5-14.9 inches (age-group VIII) and all females at 15.0-15.4 inches (age-group IX). Finclipped longnose suckers returned to spawn in the Brule River in successive years. One fish returned to spawn in 4 successive years. Many of the fish were not recaptured until 2 or 3 years after marking. The time of the Brule River spawning migration depended more on water temperature than on length of day. The average water temperature during the peak of the spawning runs of 1958-64 was 55.4 F. Larval suckers apparently spend little time in the Brule River and adjacent streams and drift downstream to the lake soon after hatching. The number of eggs in the ovaries of eight suckers ranged from 14 to 35 thousand and averaged 24 thousand for fish 13.9-17.7 inches long.

Dynamics of the recovery of the western Lake Erie walleye (Stizostedion vitreum vitreum) stock

USGS Publications Warehouse

Hatch, Richard W.; Nepszy, Stephen J.; Muth, Kenneth M.; Baker, Carl T.

1987-01-01

After its 1957 collapse under intensive fishing and environmental stresses, the walleye (Stizostedion vitreum vitreum) stock of western Lake Erie remained low throughout the 1960s. A moratorium on both sport and commercial fishing, resulting from the 1970 discovery of mercury concentrations in walleye flesh, provided an opportunity for the development of an international interagency management plan. The quota management plan developed depended on sequential projection of the fishable stock on the basis of estimated annual recruitment and reports of total withdrawals from the stock. The fishery reopened gradually and quota management (including allocation among jurisdictions) was implemented in 1976. The stock, which had been gradually increasing as a result of relatively strong year-classes produced in 1970, 1972, and 1974, responded well to limited exploitation and produced a record year-class in 1977. Quotas were exceeded in 1978-80, but the stock continued to improve to the extent that the recommended rate of exploitation was increased in 1980 and again in 1981. As the population expanded, growth began to decline; the decline became apparent in young-of-the-year in the early 1970s and in older walleyes in the late 1970s. This trend toward progressively slower growth, which continued in the 1977 and subsequent year-classes, was accompanied by an increase in length at sexual maturity and a decrease in the percentage of female walleyes reaching sexual maturity at age III. As a net result of these changes, the proportion of mature females in the stock (an index of stock fecundity) decreased slightly during the interval 1975-84, while the estimated biomass of the standing stock rose from 9 000 to nearly 26 000 t. Both sport and commercial catches increased markedly after 1980 in Lake Erie's central basin.

Subsurface Constraints on Late Cenozoic Basin Geometry in Northern Fish Lake Valley and Displacement Transfer Along the Northern Fish Lake Valley Fault Zone, Western Nevada

NASA Astrophysics Data System (ADS)

Mueller, N.; Kerstetter, S. R.; Katopody, D. T.; Oldow, J. S.

2016-12-01

The NW-striking, right-oblique Fish Lake Valley fault zone (FLVFZ) forms the northern segment of the longest active structure in the western Great Basin; the Death Valley - Furnace Creek - Fish Lake Valley fault system. Since the mid-Miocene, 50 km of right-lateral displacement is documented on the southern FLVFZ and much of that displacement was and is transferred east and north on active WNW left-lateral faults. Prior to the Pliocene, displacement was transferred east and north on a low-angle detachment. Displacement on the northern part of the FLVFZ continues and is transferred to a fanned array of splays striking (west to east) WNW, NNW, ENE and NNE. To determine the displacement budget on these structures, we conducted a gravity survey to determine subsurface basin morphology and its relation to active faults. Over 2450 stations were collected and combined with existing PACES and proprietary data for a total of 3388 stations. The data were terrain corrected and reduced to a 2.67 g/cm3 density to produce a residual complete Bouguer anomaly. The eastern part of northern Fish Lake Valley is underlain by several prominent gravity lows forming several sub-basins with maximum RCBA values ranging from -24 to -28 mGals. The RCBA was inverted for depth using Geosoft Oasis Montaj GM-SYS 3D modeling software. Density values for the inversion were constrained by lithologic and density logs from wells that penetrate the entire Cenozoic section into the Paleozoic basement. Best fitting gravity measurements taken at the wellheads yielded an effective density of 2.4 g/cm3 for the basin fill. Modeled basement depths range between 2.1 to 3 km. The sub-basins form an arc opening to the NW and are bounded by ENE and NNE faults in the south and NS to NNW in the north. At the northern end of the valley, the faults merge with ENE left-lateral strike slip faults of the Mina deflection, which carries displacement to NW dextral strike-slip faults of the central Walker Lane.

An accuracy assessment of forest disturbance mapping in the western Great Lakes

Treesearch

P.L. Zimmerman; I.W. Housman; C.H. Perry; R.A. Chastain; J.B. Webb; M.V. Finco

2013-01-01

The increasing availability of satellite imagery has spurred the production of thematic land cover maps based on satellite data. These maps are more valuable to the scientific community and land managers when the accuracy of their classifications has been assessed. Here, we assessed the accuracy of a map of forest disturbance in the watersheds of Lake Superior and Lake...

Chemical quality of surface waters in Devils Lake basin North Dakota, 1952-60

USGS Publications Warehouse

Mitten, Hugh T.; Scott, C.H.; Rosene, Philip G.

1968-01-01

Above-normal precipitation in 1954, 1956, and 1957 caused the water surface of Devils Lake to rise to an altitude of 1,419.3 feet, its highest in 40 years. Nearly all the water entering the lake flowed through Big Coulee, and about three-fourths of that inflow was at rates greater than 100 cubic feet per second. At these rates, the inflow contained less than 600 ppm (parts per million) dissolved solids and was of the calcium bicarbonate type.Because the inflow was more dilute than the lake water, the dissolved solids in the lake decreased from 8,680 ppm in 1952 to about 6,000 ppm in 1956 and 1957. Subsequently, however, they increased to slightly more than 8,000 ppm and averaged 6,800 ppm for the 1954-60 period. Sodium and sulfate were the principal dissolved constituents in the lake water. Although the concentration of dissolved solids varied significantly from time to time, the relative proportions of the chief constituents remained nearly the same.Water flowed from Devils Lake to Mission Bay in 1956,1957, and 1958, and some flowed from Mission Bay into East Bay. However, no water moved between East Devils Lake, western Stump Lake, and eastern Stump Lake during 1952-60; these lakes received only local runoff, and the variations in their water volume caused only minor variations in dissolved solids. For the periods sampled, concentrations averaged 60,700 ppm for East Devils Lake, 23,100 ppm for western Stump Lake, and 127,000 ppm for eastern Stump Lake.Sodium and sulfate were the chief dissolved constituents in all the lakes of the Devils Lake chain. Water in eastern Stump Lake was saturated with sodium sulfate and precipitated large quantities of granular, hydrated sodium sulfate crystals on the lakebed and shore in fall and winter. A discontinuous layer of consolidated sodium sulfate crystals formed a significant part of the bed throughout the year.Measured concentrations! of zinc, iron, manganese, fluoride, arsenic, boron, copper, and lead were not high enough

Fisheries research and monitoring activities of the Lake Erie Biological Station, 2015

USGS Publications Warehouse

Bodamer Scarbro, Betsy L.; Edwards, W.H.; Kocovsky, Patrick M.; Kraus, Richard T.; Rogers, M. R.; Schoonyan, A. L.; Stewart, T. R.

2016-01-01

In 2015, the U.S. Geological Survey’s (USGS) Lake Erie Biological Station (LEBS) successfully completed large vessel surveys in all three of Lake Erie’s basins. Lake Erie Biological Station’s primary vessel surveys included the Western Basin Forage Fish Assessment and East Harbor Fish Community Assessment as well as contributing to the cooperative multi-agency Central Basin Hydroacoustics Assessment, the Eastern Basin Coldwater Community Assessment, and Lower Trophic Level Assessment (see Forage and Coldwater Task Group reports). In 2015, LEBS also initiated a Lake Erie Central Basin Trawling survey in response to the need for forage fish data from Management Unit 3 (as defined by the Yellow Perch Task Group). Results from these surveys contribute to Lake Erie Committee Fish Community Goals and Objectives. Our 2015 vessel operations were initiated in early April and continued into late November. During this time, crews of the R/V Muskie and R/V Bowfin deployed 121 bottom trawls covering 83.2 ha of lake-bottom and catching 105,600 fish totaling 4,065 kg during four separate trawl surveys in the western and central basins of Lake Erie. We deployed and lifted 9.5 km of gillnet, which caught an additional 805 fish, 100 (337 kg) of which were the native coldwater predators Lake Trout, Burbot, and Lake Whitefish (these data are reported in the 2016 Coldwater Task Group report). We also conducted 317 km of hydroacoustic survey transects (reported in the 2016 Forage Task Group report), collected 114 lower trophic (i.e. zooplankton and benthos) samples, and obtained 216 water quality observations (e.g., temperature profiles, and water samples). The LEBS also assisted CLC member agencies with the maintenance and expansion of GLATOS throughout all three Lake Erie sub-basins. Within the following report sections, we describe results from three trawl surveys – the spring and autumn Western Basin Forage Fish Assessment and the East Harbor Forage Fish Assessment – and

[Endangered situation and conservation strategy of Tibetan medicine in Qinghai-Tibet Plateau].

PubMed

Zhao, Cai-Yun; Liu, Huan; Su, Jin-Song; Li, Xuan-Hao; Jia, Min-Ru; Zhang, Yi; Zhang, Jing

2016-12-01

With the rapid development of Tibetan medicine industry, the study on plateau medicinal plants' endangered status is not enough, measures to protect is weak and the plateau ecological environment' inherent vulnerability, resulted in the shortage of Tibetan medicinal resources and affect the sustainable development . According to the existing endangered information of Tibetan medicine resources, how to formulate feasible protection plan, is an urgent problem of the rational development and utilization of Tibetan medicine resources to be solved. To find out the endangered Tibetan medicines in Qinghai Tibet Plateau, the Grade division method of Chinese Rare and Endangered Plants was applied, the endangered species were sorted out, which divided into class one (threatened) eleven species, class two (rare) twenty-one species, and class three (fading) forty-two species,a total of seventy-four species.In addition to national protection list in "Chinese rare and endangered plants". It's proposed to increase the endangered Tibetan medicinal species. Finally, according to the endangered status of the resources,from the survey of endangered Tibetan medicinal species regularly, the germplasm repository establishment of endangered Tibetan medicine, in situ conservation, artificial cultivation research and renew the idea, reasonable development and utilization, a total of 5 aspects to discussed the protection strategy, to provide a scientific basis for the protection and sustainable utilization of Tibetan medicine resources in Qinghai-Tibet Plateau. Copyright© by the Chinese Pharmaceutical Association.

Miocene leaves of Elaeagnus (Elaeagnaceae) from the Qinghai-Tibet Plateau, its modern center of diversity and endemism.

PubMed

Su, Tao; Wilf, Peter; Xu, He; Zhou, Zhe-Kun

2014-08-01

• The Qinghai-Tibet Plateau is a major center of plant diversity and endemism, but little is known about how this developed due to the region's very scarce paleobotanical record. The silverberry genus Elaeagnus (Elaeagnaceae) reaches its greatest diversity (54 species) and endemism (36 species) in this area. Fossil Elaeagnaceae could provide significant evidence for the phylogeny and biogeography of the family and contribute primary data regarding the evolution of the unique Qinghai-Tibet Plateau flora in its dramatic setting of tectonic and climatic change.• We describe four fossil leaves with diagnostic features of Elaeagnus from the late Miocene of eastern Tibet, modern altitude of 3910 m a.s.l.. We also review prior fossil records of Elaeagnaceae.• The well-preserved, densely packed, stellate scales on fossil leaf surfaces are diagnostic of Elaeagnaceae. We assign these fossil leaves to Elaeagnus tibetensis T. Su et Z.K. Zhou sp. nov., comprising the first confirmed fossil Elaeagnus leaves worldwide.• Elaeagnus was present in eastern Tibet by the late Miocene. Together with previous fossil records, the new species supports a Holarctic history of the family. The diversification of Elaeagnus in the Qinghai-Tibet Plateau and adjacent areas might have been driven by continuous uplift at least since the late Miocene, causing formation of complex topography and climate with high rainfall seasonality. The characteristic scales on leaf surfaces are likely to be an important functional adaptation to seasonal droughts during early spring. © 2014 Botanical Society of America, Inc.

Effects of implementing organic rice-duck integrated farming on reducing agricultural diffuse pollution around Dianshan Lake in the western suburbs of Shanghai

NASA Astrophysics Data System (ADS)

Hu, Xue-Feng; Teng, Qing

2017-04-01

Located in the western suburbs of Shanghai, Dianshan Lake is a major source of Huangpu River, a mother river flowing through the metropolitan area. To protect the drinking water source areas, the development of any industries and livestock breeding is forbidden around the lake since the early time. However, the lake is still under a eutrophic state throughout the year. In 2013, for example, total N and total P in the lake water were 2.98 mg L-1 and 0.17 mg L-1 on average, respectively. It is believed that 72.2% of N and 73.1% of P in the lake come from agricultural diffuse pollution. The areas surrounding the lake include six towns and are all low-lying in landform. There are 5975 ha paddy fields at the six towns, making up 33.1% of total farming land in the areas. According to our questionnaires to local farmers at Jinze Town, one of the six towns, for the consecutive five years, the amounts of N and P2O5 applied within the rice growing season under the conventional rice farming are 336.6 kg ha-1 and 76.9 kg ha-1 on average, respectively, and those lost through leaching and runoff are 15.42 kg ha-1 and 3.55 kg ha-1 on average, respectively. Further study estimated that the total amounts of N and P2O5 applied around the lake within the rice growing season are 2.01×106 kg year-1 and 4.59×105 kg year-1, respectively; those lost through leaching and runoff are 0.99×105 kg year-1 and 0.23×105 kg year-1, respectively; those discharged from the fields into the lake are 0.99×104 kg year-1 and 0.23×104 kg year-1, respectively. Our study also indicated that the amount of pesticides and herbicides discharged from the paddy fields at the six towns into the lake is approximately 1.67×104 kg year-1. Appreciately, the agricultural diffuse pollution from the paddy fields surrounding the lake have posed severe threat to the lake. The field experiments indicated that raising ducks in the paddy fields within the rice growing season can not only highly reduce weed hazards and

A reworked Lake Zone margin: Chronological and geochemical constraints from the Ordovician arc-related basement of the Hovd Zone (western Mongolia)

NASA Astrophysics Data System (ADS)

Soejono, Igor; Buriánek, David; Janoušek, Vojtěch; Svojtka, Martin; Čáp, Pavel; Erban, Vojtěch; Ganpurev, Nyamtsetseg

2017-12-01

The primary relationships and character of the boundaries between principal lithotectonic domains in the Mongolian tract of the Central Asian Orogenic Belt (CAOB) are still poorly constrained. This brings much uncertainty in understanding of the orogeny configuration and the complete accretionary history. The plutonic Khuurai Tsenkher Gol Complex and the mainly metasedimentary Bij Group represent associated medium- to high-grade basement complexes exposed in the Hovd Zone close to its boundary with the Lake Zone in western Mongolia. The Khuurai Tsenkher Gol Complex is composed of variously deformed acid to basic magmatic rocks intimately associated with the metamorphosed sedimentary and volcanic rocks of the Bij Group. Results of our field work, new U-Pb zircon ages and whole-rock geochemical data suggest an existence of two separate magmatic events within the evolution of the Khuurai Tsenkher Gol Complex. Early to Mid-Ordovician (476 ± 5 Ma and 467 ± 4 Ma protoliths) normal- to high-K calc-alkaline orthogneisses, metadiorites and metagabbros predominate over Mid-Silurian (430 ± 3 Ma) tholeiitic-mildly alkaline quartz monzodiorites. Whereas the geochemical signature of the former suite unequivocally demonstrates its magmatic-arc origin, that of the latter quartz monzodiorite suggests an intra-plate setting. As shown by Sr-Nd isotopic data, the older arc-related magmas were derived from depleted mantle and/or were generated by partial melting of juvenile metabasic crust. Detrital zircon age populations of the metasedimentary rocks together with geochemical signatures of the associated amphibolites imply that the Bij Group was a volcano-sedimentary sequence, formed probably in the associated fore-arc wedge basin. Moreover, our data argue for an identical provenance of the Altai and Hovd domains, overall westward sediment transport during the Early Palaeozoic and the east-dipping subduction polarity. The obvious similarities of the Khuurai Tsenkher Gol Complex

Molecular phylogeny and biogeography of the Qinghai-Tibet Plateau endemic Nannoglottis (Asteraceae).

PubMed

Liu, Jian-Quan; Gao, Tian-Gang; Chen, Zhi-Duan; Lu, An-Ming

2002-06-01

All taxa endemic to the Qinghai-Tibet Plateau are hypothesized to have originated in situ or from immediately adjacent areas because of the relatively recent formation of the plateau since the Pliocene, followed by the large-scaled biota extinction and recession caused by the Quaternary ice sheet. However, identification of specific progenitors remains difficult for some endemics, especially some endemic genera. Nannoglottis, with about eight species endemic to this region, is one such genus. Past taxonomic treatments have suggested its relationships with four different tribes of Asteraceae. We intend to identify the closest relatives of Nannoglottis by evaluating the level of monophyly, tribal delimitation, and systematic position of the genus by using molecular data from ndhF gene, trnL-F, and ITS region sequences. We find that all sampled species of Nannoglottis are a well-defined monophyly. This supports all recent taxonomic treatments of Nannoglottis, in which all sampled species were placed in one broadly re-circumscribed genus. Nannoglottis is most closely related to the Astereae, but stands as an isolated genus as the first diverging lineage of the tribe, without close relatives. A tentative relationship was suggested for Nannoglottis and the next lineage of the tribe was based on the ITS topology, the "basal group," which consists of seven genera from the Southern Hemisphere. Such a relationship is supported by some commonly shared plesiomorphic morphological characters. Despite the very early divergence of Nannoglottis in the Astereae, the tribe must be regarded to have its origin in Southern Hemisphere rather than in Asia, because based on all morphological, molecular, biogeographical, and fossil data, the Asteraceae and its major lineages (tribes) are supposed to have originated in the former area. Long-distance dispersal using Southeast Asia as a steppingstone from Southern Hemisphere to the Qinghai-Tibet Plateau is the most likely explanation for this

Landform-related permafrost characteristics in the source area of the Yellow River, eastern Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

Li, Jing; Sheng, Yu; Wu, Jichun; Feng, Ziliang; Ning, Zuojun; Hu, Xiaoying; Zhang, Xiumin

2016-09-01

The source area of the Yellow River (SAYR) lies in the eastern part of the Qinghai-Tibet Plateau (QTP). Glaciers are absent in the area, but permafrost is widespread because of the high elevations, typically 4200-5000 m a.s.l. Landforms in the SAYR were classified into seven basic types, based on their morphological characteristics and genesis, and further divided into 12 sub-classes based on geomorphic processes. Permafrost development and ground temperature in boreholes were analyzed on representative landforms in the SAYR. Permafrost was discontinuously distributed at 4300-4400 m a.s.l. in fluvial plains because of variations in local topography, sediments, vegetation and water content. In hills and low-relief mountains in the western part of the study area, permafrost is continuous above 4400 m a.s.l. even on unshaded south-facing slopes. In contrast, permafrost in the central part of the study area is discontinuous over this elevation range. Analysis of ground temperature measurements revealed that three macro-scale factors, latitude, longitude, and elevation, explain 72.8% of the variation in the measured mean annual ground temperature (MAGT). The remaining 27.2% can potentially be explained by variations in topography and land cover within the SAYR.

Olfactory and visual responses of the long-legged chafer hoplia spectabilis medvedev (Coleoptera: Scarabaeidae) in Qinghai province, China

USDA-ARS?s Scientific Manuscript database

The long-legged chafer, Hoplia spectabilis Medvedev (Coleoptera: Scarabaeidae), has recently been recorded in outbreak numbers in pastureland of Qinghai province, China. It is causing significant damage to several species of woody shrubs, especially Hippophae neurocarpa Liu and Ho (Elaeagnaceae), D...

Temporal patterns of glacial lake evolution in high-mountain environments

NASA Astrophysics Data System (ADS)

Mergili, Martin; Emmer, Adam; Viani, Cristina; Huggel, Christian

2017-04-01

Lakes forming at the front of retreating glaciers are characteristic features of high-mountain areas in a warming climate. Typically, lakes shift from the proglacial phase (lake is in direct contact with glacier) to a glacier-detached (no direct contact) and finally to a non-glacial phase (lake catchment is completely deglaciated) of lake evolution. Apart from changing glacier-lake interactions, each stage is characterized by particular features of lake growth, and by the lake's susceptibility to sudden drainage (lake outburst flood). While this concept appears to be valid globally, some mountain areas are rich in dynamically evolving proglacial lakes, while in others most lakes have already shifted to the glacier-detached or even non-glacial phase. In the present contribution we (i) explore and quantify the history of glacial lake formation and evolution over the past up to 70 years; (ii) assess the current situation of selected contrasting mountain areas (eastern and western European Alps, southern and northern Pamir, Cordillera Blanca); and (iii) link the patterns of lake evolution to the prevailing topographic and glaciological characteristics in order to improve the understanding of high-mountain geoenvironmental change. In the eastern Alps we identify only very few lakes in the proglacial stage. While many lakes appeared and dynamically evolved until the 1980s between 2550 m and 2800 m asl, most of them have lost glacier contact until the 2000s, whereas very few new proglacial lakes appeared at the same time. Even though a similar trend is observed in the higher western Alps, a more dynamic glacial lake evolution is observed there. The arid southern Pamir is characterized by a high number of proglacial lakes, mainly around 4500 m asl. There is strong evidence that glacial lake evolution is, after a highly dynamic phase between the 1970s and approx. 2000, decelerating. Few proglacial lakes exist in the higher and more humid, heavily glacierized northern Pamir

[Environmental efficiency evaluation under carbon emission constraint in Western China].

PubMed

Rong, Jian-bo; Yan, Li-jiao; Huang, Shao-rong; Zhang, Ge

2015-06-01

This research used the SBM model based on undesirable outputs to measure the static environmental efficiency of Western China under carbon emission constraint from 2000 to 2012. The researchers also utilized the Malmquist index to further analyze the change tendency of environmental efficiency. Additionally, Tobit regression analysis was used to study the factors relevant to environmental efficiency. Practical solutions to improve environmental quality in Western China were put forward. The study showed that in Western China, environmental efficiency with carbon emission constraint was significantly lower than that without carbon emission constraint, and the difference could be described as an inverse U-shaped curve which increased at first and then decreased. Guang-xi and Inner Mongolia, the two provinces met the effective environmental efficiency levels all the time under carbon emission constraint. However, the five provinces of Guizhou, Gansu, Qinghai, Ningxia and Xinjiang did not. Furthermore, Ningxia had the lowest level of environmental efficiency, with a score between 0.281-0.386. Although the environmental efficiency of most provinces was currently at an ineffective level, the environmental efficiency quality was gradually improving at an average speed of 6.6%. Excessive CO2 emission and a large amount of energy consumption were the primary factors causing environmental inefficiency in Western China, and energy intensity had the most negative impact on the environmental efficiency. The increase of import and export trade reduced the environmental efficiency significantly in Western China, while the increase of foreign direct investment had a positive effect on its environmental efficiency.

Forecasting daily lake levels using artificial intelligence approaches

NASA Astrophysics Data System (ADS)

Kisi, Ozgur; Shiri, Jalal; Nikoofar, Bagher

2012-04-01

Accurate prediction of lake-level variations is important for planning, design, construction, and operation of lakeshore structures and also in the management of freshwater lakes for water supply purposes. In the present paper, three artificial intelligence approaches, namely artificial neural networks (ANNs), adaptive-neuro-fuzzy inference system (ANFIS), and gene expression programming (GEP), were applied to forecast daily lake-level variations up to 3-day ahead time intervals. The measurements at the Lake Iznik in Western Turkey, for the period of January 1961-December 1982, were used for training, testing, and validating the employed models. The results obtained by the GEP approach indicated that it performs better than ANFIS and ANNs in predicting lake-level variations. A comparison was also made between these artificial intelligence approaches and convenient autoregressive moving average (ARMA) models, which demonstrated the superiority of GEP, ANFIS, and ANN models over ARMA models.

Map of Western Copper River Basin, Alaska, Showing Lake Sediments and Shorelines, Glacial Moraines, and Location of Stratigraphic Sections and Radiocarbon-Dated Samples

USGS Publications Warehouse

Williams, John R.; Galloway, John P.

1986-01-01

The purpose of this report is to make available basic data on radiocarbon dating of 61 organic samples from 40 locations in the western Copper River Basin and adjacent uplands and in the uppermost Matanuska River Valley. The former distribution of late Quaternary glacial lakes and of glaciers as mapped from field work and photo interpretation is provided as background for interpretation of the radiocarbon dates and are the basic data needed for construction of the late Quaternary chronology. The glacial boundaries, formed and expressed by moraines, ice-contact margins, marginal channels, deltas, and other features, are obscured by a drape of glaciolacustrine deposits in a series of glacial lakes. The highest lake, represented by bottom sediments as high as 914 m to 975 m above sea level, extends from Fog Lakes lowland on Susitna River upstream into the northwestern part of the Copper River Basin (the part now draining to Susitna River) where it apparently was held in by an ice border. It was apparently dammed by ice from the Mt. McKinley area, by Talkeetna G1acier, and may have had a temporary drainage threshold at the headwaters of Chunilna Creek. No shorelines have been noted within the map area, although Nichols and Yehle (1961) reported shorelines within the 914-975 m range in the Denali area to the north of that mapped. Recent work by geologic consultants for the Susitna Hydroelectric Project has confirmed the early inferences (Karlstrom, 1964) about the existence of a lake in the Susitna canyon, based originally on drilling by the Bureau of Reclamation about 35 years ago. According to dating of deposits at Tyone Bluff (map locations 0, P), Thorson and others (1981) concluded that a late Wisconsin advance of the glaciers between 11,535 and 21,730 years ago was followed by a brief interval of lacustrine sedimentation, and was preceded by a long period of lake deposition broken by a lowering of the lake between 32,000 and about 25,000 years ago. An alternate

Numerical investigation with a coupled single-column lake-atmosphere model: An application to Western Switzerland

NASA Astrophysics Data System (ADS)

Goyette, Stéphane

2017-04-01

The potential of a novel atmospheric single-column model (SCM) developed in the framework of the Canadian Regional Climate Model, CRCM, driven by NCEP-NCAR reanalyses is investigated. The approach to solve the model equations and the technique described here may be implemented in any RCM system environment as a model option. The working hypothesis underlying this SCM formulation is that a substantial portion of the variability simulated in the column can be reproduced by processes operating in the vertical dimension and a lesser portion comes from processes operating in the horizontal dimension. This SCM offers interesting prospects as the horizontal and vertical resolution of the RCM is ever increasing. Due to its low computational cost, multiple simulations may be carried out in a short period of time. In this paper, a range of possible results from changing the lower boundary from land to open water surface, and varying model parameters are shown for western Switzerland. The benefit of using Newtonian relaxation, or "nudging", is demonstrated. Results show that air temperature, moisture and windspeed profiles are modified in a coherent manner in the lowest levels. Such changes are consistent with those of the surface vertical sensible, latent heat and momentum fluxes. Compared to atmospheric profiles over land, switching to and open water surface representative of Lake Geneva over the annual cycle of 1990, air temperature is increased by up to 1°C during the autumn and winter seasons, and by 0.5°C during the spring and summer seasons. Specific humidity is increased by up to 0.2 g kg-1 during the autumn and winter seasons and decreased by 0.3 g kg-1 during the spring and summer seasons. The increased windspeed at the surface, often more than 1.5 m s-1, is due to the smaller roughness height. The surface radiation and energy budgets are also modified subsequent to the different partionning of the latent end sensible heat fluxes, but also the solar and thermal

Remote Sensing and Shallow Geophysical Investigations on Moghra Lake in Northeastern Qattarra Depression, Western Desert, Egypt

NASA Astrophysics Data System (ADS)

Khan, S. D.; Fathy, M. S.; Azeem, M. A.

2012-12-01

The Western Desert of Egypt encompasses two thirds of the land area of Egypt and constitutes one of the driest regions of the Sahara. This desert has seven depressions; Siwa, Qattara, Fayium, Bahariya, Farafra, Dakhla and Kharga. These depressions may be the manifestation of old drainage basins with extensive erosion and possibly some tectonic activity. Several oases with freshwater can be found in these depressions. Geological and geophysical investigations in Qattara Depression indicate several buried fluvial channels with flow direction from highlands in southeast to northwest. Moghra Lake at the northeastern tip of Qatarra basin may be a small remnant of a larger paleo-lake including the mouth of a paleo-river. This study probed this area for presence of buried channels that may have fed the larger Moghra paleo-lake. We have used ALOS - PALSAR radar remote sensing data to identify the surface features in this region, such as channels, channel fills, and fractures. In addition, dual polarization PALSAR data (HV, HH) allowed analysis of the near surface geology and assisted in delineating areas of interest for GPR surveys. GPR data along 2D profiles were acquired using the GSSI SIR-3000 system with a 400 MHz antenna that provided images to approximately three meters in depth. All the GPS data were processed using RADAN 6.6 software. A conventional processing flow was used for data processing: The positional correction tool removed the air wave. A range-gain balanced the amplitudes and a final band-pass (50 kHz to 500 kHz) filter was applied to the data. Deconvolution was also applied for highlighting the finer details. In addition, spatial filters were used to attenuate continuous vertical noise. The migrated sections of GPR identified a major paleochannel distributary with two minor channels at the margins. The bedrock of the studied area consists of the Lower Miocene Moghra Formation (sandstone and shale intercalations). The area around the present lake is

Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication--A Case Study in the Taihu Lake Basin (China).

PubMed

Lin, Chen; Ma, Ronghua; He, Bin

2015-12-24

Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r² was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality.

Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication—A Case Study in the Taihu Lake Basin (China)

PubMed Central

Lin, Chen; Ma, Ronghua; He, Bin

2015-01-01

Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r2 was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality. PMID:26712772

Epidemiology of Echinococcosis Among Schoolchildren in Golog Tibetan Autonomous Prefecture, Qinghai, China.

PubMed

Cai, Huixia; Guan, Yayi; Ma, Xiao; Wang, Liying; Wang, Hu; Su, Guoming; Zhang, Xuefei; Han, Xiumin; Ma, Junying; Liu, Yu Fang; Li, Jun; Zhang, Jingxiao; Wang, Yongshun; Wang, Wei; Du, Rui; Lei, Wen; Wu, Weiping

2017-03-01

Echinococcosis is a serious zoonotic parasitic disease that is highly endemic in Qinghai Province. The present study aimed to investigate the prevalence of echinococcosis among schoolchildren in Golog Tibetan Autonomous Prefecture to improve early diagnosis and treatment of patients and to provide information for echinococcosis prevention and control. A total of 11,260 schoolchildren from five counties (Maqin, Gander, Dari, Jiuzhi, and Banma) in Golog Tibetan Autonomous Prefecture, Qinghai Province, were screened for echinococcosis. Screening involved ultrasound imaging combined with serologic examination as an auxiliary diagnostic test. The prevalence of echinococcosis in the schoolchildren was 2.1% (235/11,260), with a rate of 0.8% for cystic echinococcosis (CE; 89/11,260) and 1.3% for alveolar echinococcosis (AE; 146/11,260). Additionally, one child had a mixed infection. The prevalence ranged between 1.1% and 4.1% among the five investigated counties, and was highest in Dari County (4.1%). The prevalence of echinococcosis was higher in girls than in boys and gradually increased with age. In addition, children with CE mainly had type 1 (CE1) and type 3 (CE3) lesions, and children with AE mainly had small-diameter calcified lesions, suggesting that they were in the early asymptomatic stage of echinococcosis. In conclusion, children of Golog Tibetan Autonomous Prefecture appear to exhibit the highest recorded prevalence of CE and AE globally. Ultrasound is useful for screening populations in regions where both CE and AE are endemic.

Epidemiology of Echinococcosis among Schoolchildren in Golog Tibetan Autonomous Prefecture, Qinghai, China

PubMed Central

Cai, Huixia; Guan, Yayi; Ma, Xiao; Wang, Liying; Wang, Hu; Su, Guoming; Zhang, Xuefei; Han, Xiumin; Ma, Junying; Liu, Yu Fang; Li, Jun; Zhang, Jingxiao; Wang, Yongshun; Wang, Wei; Du, Rui; Lei, Wen; Wu, Weiping

2017-01-01

Echinococcosis is a serious zoonotic parasitic disease that is highly endemic in Qinghai Province. The present study aimed to investigate the prevalence of echinococcosis among schoolchildren in Golog Tibetan Autonomous Prefecture to improve early diagnosis and treatment of patients and to provide information for echinococcosis prevention and control. A total of 11,260 schoolchildren from five counties (Maqin, Gander, Dari, Jiuzhi, and Banma) in Golog Tibetan Autonomous Prefecture, Qinghai Province, were screened for echinococcosis. Screening involved ultrasound imaging combined with serologic examination as an auxiliary diagnostic test. The prevalence of echinococcosis in the schoolchildren was 2.1% (235/11,260), with a rate of 0.8% for cystic echinococcosis (CE; 89/11,260) and 1.3% for alveolar echinococcosis (AE; 146/11,260). Additionally, one child had a mixed infection. The prevalence ranged between 1.1% and 4.1% among the five investigated counties, and was highest in Dari County (4.1%). The prevalence of echinococcosis was higher in girls than in boys and gradually increased with age. In addition, children with CE mainly had type 1 (CE1) and type 3 (CE3) lesions, and children with AE mainly had small-diameter calcified lesions, suggesting that they were in the early asymptomatic stage of echinococcosis. In conclusion, children of Golog Tibetan Autonomous Prefecture appear to exhibit the highest recorded prevalence of CE and AE globally. Ultrasound is useful for screening populations in regions where both CE and AE are endemic. PMID:28070013

Combining lake and watershed characteristics with Landsat TM data for remote estimation of regional lake clarity

USGS Publications Warehouse

McCullough, Ian M.; Loftin, Cyndy; Sader, Steven A.

2012-01-01

Water clarity is a reliable indicator of lake productivity and an ideal metric of regional water quality. Clarity is an indicator of other water quality variables including chlorophyll-a, total phosphorus and trophic status; however, unlike these metrics, clarity can be accurately and efficiently estimated remotely on a regional scale. Remote sensing is useful in regions containing a large number of lakes that are cost prohibitive to monitor regularly using traditional field methods. Field-assessed lakes generally are easily accessible and may represent a spatially irregular, non-random sample of a region. We developed a remote monitoring program for Maine lakes >8 ha (1511 lakes) to supplement existing field monitoring programs. We combined Landsat 5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) brightness values for TM bands 1 (blue) and 3 (red) to estimate water clarity (secchi disk depth) during 1990–2010. Although similar procedures have been applied to Minnesota and Wisconsin lakes, neither state incorporates physical lake variables or watershed characteristics that potentially affect clarity into their models. Average lake depth consistently improved model fitness, and the proportion of wetland area in lake watersheds also explained variability in clarity in some cases. Nine regression models predicted water clarity (R2 = 0.69–0.90) during 1990–2010, with separate models for eastern (TM path 11; four models) and western Maine (TM path 12; five models that captured differences in topography and landscape disturbance. Average absolute difference between model-estimated and observed secchi depth ranged 0.65–1.03 m. Eutrophic and mesotrophic lakes consistently were estimated more accurately than oligotrophic lakes. Our results show that TM bands 1 and 3 can be used to estimate regional lake water clarity outside the Great Lakes Region and that the accuracy of estimates is improved with additional model variables that reflect

General view of Quarters (Building No. 44) and Lake Jeanette ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view of Quarters (Building No. 44) and Lake Jeanette looking southeast. - National Home for Disabled Volunteer Soldiers, Western Branch, Quarters, Franklin Avenue, Leavenworth, Leavenworth County, KS

Numerical methods for assessing water quality in lakes and reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahamah, D.S.

1984-01-01

Water quality models are used as tools for predicting both short-term and long-term trends in water quality. They are generally classified into two groups based on the degree of empiricism. The two groups consists of the purely empirical types known as black-box models and the theoretical types called ecosystem models. This dissertation deals with both types of water quality models. The first part deals with empirical phosphorus models. The theory behind this class of models is discussed, leading to the development of an empirical phosphorus model using data from 79 western US lakes. A new approach to trophic state classificationmore » is introduced. The data used for the model was obtained from the Environmental Protection Agency National Eutrophication Study (EPA-NES) of western US lakes. The second portion of the dissertation discusses the development of an ecosystem model for culturally eutrophic Liberty Lake situated in eastern Washington State. The model is capable of simulating chlorophyll-a, phosphorus, and nitrogen levels in the lake on a weekly basis. For computing sediment release rates of phosphorus and nitrogen, equations based on laboratory bench-top studies using sediment samples from Liberty Lake are used. The model is used to simulate certain hypothetical nutrient control techniques such as phosphorus flushing, precipitation, and diversion.« less

Paleoecology of a Northern Michigan Lake and the relationship among climate, vegetation, and Great Lakes water levels

USGS Publications Warehouse

Booth, R.K.; Jackson, S.T.; Thompson, T.A.

2002-01-01

We reconstructed Holocene water-level and vegetation dynamics based on pollen and plant macrofossils from a coastal lake in Upper Michigan. Our primary objective was to test the hypothesis that major fluctuations in Great Lakes water levels resulted in part from climatic changes. We also used our data to provide temporal constraints to the mid-Holocene dry period in Upper Michigan. From 9600 to 8600 cal yr B.P. a shallow, lacustrine environment characterized the Mud Lake basin. A Sphagnum-dominated wetland occupied the basin during the mid-Holocene dry period (???8600 to 6600 cal yr B.P.). The basin flooded at 6600 cal yr B.P. as a result of rising water levels associated with the onset of the Nipissing I phase of ancestral Lake Superior. This flooding event occured contemporaneously with a well-documented regional expansion of Tsuga. Betula pollen increased during the Nipissing II phase (4500 cal yr B.P.). Macrofossil evidence from Mud Lake suggests that Betula alleghaniensis expansion was primarily responsible for the rising Betula pollen percentages. Major regional and local vegetational changes were associated with all the major Holocene highstands of the western Great Lakes (Nipissing I, Nipissing II, and Algoma). Traditional interpretations of Great Lakes water-level history should be revised to include a major role of climate. ?? 2002 University of Washington.

Geohydrology of the lowland lakes area, Anchorage, Alaska

USGS Publications Warehouse

Zenone, Chester

1976-01-01

Unconsolidated deposits, chiefly of glacial origin, make up the surficial geologic materials in the Anchorage lowland lakes area , the western part of the Anchorage glacial outwash plain. Postglacial accumulation of peat, commonly 5 to 10 feet thick, and the presence of ground water at or very near the surface combine to create the swamp-muskeg terrane of much of the area. Deeper, confined ground water is also present beneath thick silt and clay layers that underlie the surficial deposits. Domestic water supply for the lowland lakes area is provided largely by public-supply wells completed in the deep, confined aquifers. No large perennial streams traverse the area, thus streamflow is not a major parameter in the area 's natural water balance. The major uses of surface water are recreational, including fishing and boating at several of the larger lakes, and private and commercial aircraft operations at Hood-Spenard Lakes floatplane base. The hydrology and water balance of these lakes is complex. Water levels in some lakes appear to be closely related to adjacent ground-water levels. Other lakes are evidently perched above the local water table. The relation of lake level to adjacent ground-water level may vary along the shoreline of a single lake. The effect of residential development practices on lake basin water balance is not completely understood. At Sand Lake, the largest lake in this area of rapid urbanization, the water level has declined about 6 feet since the early 1960's. (Woodard-USGS)

Salamander colonization of Chase Lake, Stutsman County, North Dakota

USGS Publications Warehouse

Mushet, David M.; McLean, Kyle I.; Stockwell, Craig A.

2013-01-01

Salt concentrations in lakes are dynamic. In the western United States, water diversions have caused significant declines in lake levels resulting in increased salinity, placing many aquatic species at risk (Galat and Robinson 1983, Beutel et al. 2001). Severe droughts can have similar effects on salt concentrations and aquatic communities (Swanson et al. 2003). Conversely, large inputs of water can dilute salt concentrations and contribute to community shifts (Euliss et al. 2004).

33 CFR 165.901 - Great Lakes-regulated navigation areas.

Code of Federal Regulations, 2012 CFR

2012-07-01

... waters of Lake Huron known as South Channel between Bois Blanc Island and Cheboygan, Michigan; bounded by a line north from Cheyboygan Crib Light (LL-1340) at 45°39′48″ N, 84°27′36″ W; to Bois Blanc Island... western tangent of Bois Blanc Island at 45°48′42″ N, 84°35′30″ W. (2) The waters of Lake Huron between...

33 CFR 165.901 - Great Lakes-regulated navigation areas.

Code of Federal Regulations, 2010 CFR

2010-07-01

... waters of Lake Huron known as South Channel between Bois Blanc Island and Cheboygan, Michigan; bounded by a line north from Cheyboygan Crib Light (LL-1340) at 45°39′48″ N, 84°27′36″ W; to Bois Blanc Island... western tangent of Bois Blanc Island at 45°48′42″ N, 84°35′30″ W. (2) The waters of Lake Huron between...

33 CFR 165.901 - Great Lakes-regulated navigation areas.

Code of Federal Regulations, 2013 CFR

2013-07-01

... waters of Lake Huron known as South Channel between Bois Blanc Island and Cheboygan, Michigan; bounded by a line north from Cheyboygan Crib Light (LL-1340) at 45°39′48″ N, 84°27′36″ W; to Bois Blanc Island... western tangent of Bois Blanc Island at 45°48′42″ N, 84°35′30″ W. (2) The waters of Lake Huron between...

33 CFR 165.901 - Great Lakes-regulated navigation areas.

Code of Federal Regulations, 2011 CFR

2011-07-01

... waters of Lake Huron known as South Channel between Bois Blanc Island and Cheboygan, Michigan; bounded by a line north from Cheyboygan Crib Light (LL-1340) at 45°39′48″ N, 84°27′36″ W; to Bois Blanc Island... western tangent of Bois Blanc Island at 45°48′42″ N, 84°35′30″ W. (2) The waters of Lake Huron between...

A Relationship Between Microbial Activity in Soils and Phosphate Levels in Tributaries to Lake Champlain

NASA Astrophysics Data System (ADS)

Larose, R.; Lee, S.; Lane, T.

2015-12-01

Lake Champlain is a large natural freshwater lake. It forms the western boundary of Vermont and drains over half of the state. It is bordered by the state of New York on its western side and drains to the north into Quebec, Canada. Lake Champlain is the source of fresh drinking water for over quarter of a million people and provides for the livelihoods and recreational opportunities of many well beyond its borders. The health of this lake is important. During the summer month's algae blooms plague the lake. These unsightly growths, which affect other aquatic organisms, are the result of excess phosphate flowing into the lake from many sources. Examining whether there is a relationship between microbial activity in the soils bordering tributaries to Lake Champlain and phosphate levels in those tributaries sheds insight into the origins and paths by which phosphate moves into Lake Champlain. Understanding the how phosphate moves into the water system may assist in mitigation efforts.Total Phosphate levels and Total Suspended Solids were measured in second and third order streams in the Lake Champlain Basin over a three-year period. In addition microbial activity was measured within the toe, bank and upland riparian zone areas of these streams during the summer months. In general in areas showing greater microbial activity in the soil(s) there were increased levels of phosphate in the streams.

Life history of the gizzard shad, Dorosoma cepedianum (Le Sueur), in western Lake Erie

USGS Publications Warehouse

Bodola, Anthony

1966-01-01

The rapid increase in the stocks of gizzard shad in Lake Erie since 1950 unquestionably had an important effect on the ecology of the lake. The present study, based on almost 24,000 fish collected by various means in 1952-55 in or near the island area of western Lake Erie was undertaken to provide information on the role of shad in the bionomics of the region. The annulus of the gizzard shad scale is a valid year-mark. It is laid down in May-July, a little later in the older than in the younger fish. The body-scale relation is linear with an intercept of 22.1 mm. on the axis of standard length. Age-groups 0, I, and II were abundantly represented in the samples. Age-group III was much less well represented, and older fish were extremely scarce. The oldest shad seen belonged to the VI-group. The seasonal growth was most rapid in July-August and growth was much reduced or nil in January-April. Males attained the following average standard lengths (in millimeters) at the end of the indicated years of life: 1-141; 2-273; 3-313; 4-343; 5-349. For females these values were 1-140; 2-285; 3-335; 4-364; 5-386. The weight of the gizzard shad increased as the 3.07053 power of the length. The length-weight relation varied seasonally, annually, and, near the spawning season, according to sex and state of gonads. Only a few precocious male and female gizzard shad attain sexual maturity as age-group I. Almost all males and a good percentage of females mature at age II and only rarely are III-group shad immature. Development of the egg and seasonal changes of the ovary are described. Egg production is highest in the II group-average of 378,900 per individual and 689 per gram of body weight. Spawning takes place from early June into July and is most intensive near mid-June. Heaviest spawning is at water temperatures of 67A?F. or more. Early development to the attainment of the adult shape is described; particular attention is given to the development of the alimentary tract. The

Temporal variation in fish mercury concentrations within lakes from the western Aleutian Archipelago, Alaska

USGS Publications Warehouse

Kenney, Leah A.; Eagles-Smith, Collin A.; Ackerman, Joshua T.; von Hippel, Frank A.

2014-01-01

We assessed temporal variation in mercury (Hg) concentrations of threespine stickleback (Gasterosteus aculeatus) from Agattu Island, Aleutian Archipelago, Alaska. Total Hg concentrations in whole-bodied stickleback were measured at two-week intervals from two sites in each of two lakes from June 1 to August 10, 2011 during the time period when lakes were ice-free. Across all sites and sampling events, stickleback Hg concentrations ranged from 0.37–1.07 µg/g dry weight (dw), with a mean (± SE) of 0.55±0.01 µg/g dw. Mean fish Hg concentrations declined by 9% during the study period, from 0.57±0.01 µg/g dw in early June to 0.52±0.01 µg/g dw in mid-August. Mean fish Hg concentrations were 6% higher in Loon Lake (0.56±0.01 µg/g dw) than in Lake 696 (0.53±0.01 µg/g dw), and 4% higher in males (0.56±0.01 µg/g dw) than in females (0.54±0.01 µg/g dw). Loon Lake was distinguished from Lake 696 by the presence of piscivorous waterbirds during the breeding season. Mercury concentrations in stickleback from Agattu Island were higher than would be expected for an area without known point sources of Hg pollution, and high enough to be of concern to the health of piscivorous wildlife.

A coupled lake-atmosphere model (CLAM) and its application to Lake Kinneret

NASA Astrophysics Data System (ADS)

Pan, Hai

1999-08-01

and 22-km long), the micrometeorological conditions, lake currents and thermal structure, and the lake-surface heat fluxes vary spatially very significantly, even on a daily basis. It is found that the daily-mean wind curl, which is predominantly determined by the passage of the Mediterranean Sea breeze (MSB) over the lake, is mostly responsible for the gyres in the lake. The thermocline oscillation in the lake is mainly controlled by the surface elevation set up by the time-dependent winds. The intense MSB over the lake in the late afternoon pushes the heated surface water eastward, forces the deep, cooler water to be advected westward, and creates strong mixing in the lake, resulting in a higher temperature off the eastern shore and a lower temperature off the western shore. The variation of lake-surface temperature not only directly affects the atmospheric processes over the lake, but it also changes the wind field, which then influences hydrodynamic processes in the lake. An analytical model of the flow response to spatial variation of atmospheric cooling in coastal ocean was also developed in this study. This model is used to explain the contribution of the spatial variation of latent heat flux to the circulation in Lake Kinneret, and also the cyclonic flow, which is observed in many lakes and semi-enclosed coastal oceans.

Antarctic lakes (above and beneath the ice sheet): Analogues for Mars

NASA Technical Reports Server (NTRS)

Rice, J. W., Jr.

1992-01-01

The perennial ice covered lakes of the Antarctic are considered to be excellent analogues to lakes that once existed on Mars. Field studies of ice covered lakes, paleolakes, and polar beaches were conducted in the Bunger Hills Oasis, Eastern Antarctica. These studies are extended to the Dry Valleys, Western Antarctica, and the Arctic. Important distinctions were made between ice covered and non-ice covered bodies of water in terms of the geomorphic signatures produced. The most notable landforms produced by ice covered lakes are ice shoved ridges. These features form discrete segmented ramparts of boulders and sediments pushed up along the shores of lakes and/or seas. Sub-ice lakes have been discovered under the Antarctic ice sheet using radio echo sounding. These lakes occur in regions of low surface slope, low surface accumulations, and low ice velocity, and occupy bedrock hollows. The presence of sub-ice lakes below the Martian polar caps is possible. The discovery of the Antarctic sub-ice lakes raises possibilities concerning Martian lakes and exobiology.

Tracers Show Ecohydrologic Influences on Runoff Generation Components at the Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

Liu, H.; Liu, J.; Peng, A.; Gu, W.; Wang, W.; Gao, F.

2017-12-01

In order to learn more about the critical zone ecohydrological dynamics at the Qinghai-Tibet Plateau, a research on the identification of runoff components using tracers was carried out in the Niyang River upstream, a tributary of the Yalung Zangbo River. In this study, four basins with the areas of 182, 216, 243, 213 km2 which are embed in a larger basin were sampled at altitudes between 3667 to 6140 m. The types of land use in the basins mainly include forest land, grassland and glacier. River water and precipitation were sampled monthly, while spring water, glacial ice, soil, and plants were sampled seasonally. Soil and plant samples were taken along the valleys with spatial interval of about 5 km. Soil and plant waters were extracted via cryogenic vacuum distillation method, and then analyzed for isotopes and ions. Preliminary results show that the δD and δ18O of the precipitation water spread approximately along the LMWL of the Namucuo Lake near Lasa city, which varied according to altitude. Stem water δD and δ18O from different elevations and tree species also varied regularly, albeit with no apparent relationship to recent precipitation. It appears that trees utilized fissure water and soil water formed by precipitation. Future efforts will involve (1) an expanded sampling strategy across basins, and (2) a series of experiments on the Hydrohill catchment in the Chuzhou Experimental Facility, whereby an improved understanding of K+, Na+, Ca2+ and Mg2+ export dynamics could aid in much better description and modeling of Niyang River runoff composition and generation. This research is funded by the NSFC project 91647111 and 91647203, which are included in the Runoff Change and its Adaptive Management in the Major Rivers in Southwestern China Major Research Plan.

Invertebrate communities associated with Bangia atropurpurea and Cladophora glomerata in western Lake Erie

USGS Publications Warehouse

Chilton, E.W.; Lowe, R.L.; Schurr, K.M.

1986-01-01

The appearance of the marine alga Bangia atropurpurea (Rhodophyta) in Lake Erie has been followed by its rapid dispersal throughout the eulittoral zone of the lake. Bangia was extensively sampled to determine its suitability as a habitat for littoral organisms. Present data indicate that the only organisms capable of maintaining populations on Bangia filaments are larval Chironomidae. Cladophora supports a larger and more diverse community. It is concluded that the mucilaginous cell wall of Bangia provides a less stable substrate for attached or clinging organisms than does the cellulose cell wall of Cladophora. The presence of Bangia in the littoral zone of Lake Erie results in a reduction of the quantity and diversity of algal epiphytes and may negatively impact the littoral food web.

Intense uplift of the Qinghai-Tibetan Plateau triggered rapid diversification of Phyllolobium (Leguminosae) in the Late Cenozoic

Treesearch

Ming-Li Zhang; Yun Kang; Yang Zhong; Stewart C. Sanderson

2012-01-01

Phyllolobium, a recently established genus from subgenus Pogonophace of Astragalus, contains about 20 species and four sections, mostly endemic to the Qinghai-Tibetan Plateau (QTP). The uplift of the QTP undoubtedly affected organismic evolution in the region, but further molecular dating in a phylogenetic context is required to test whether diversification is linked...

Last glacial maximum and Holocene lake levels of Owens Lake, eastern California, USA

USGS Publications Warehouse

Bacon, S.N.; Burke, R.M.; Pezzopane, S.K.; Jayko, A.S.

2006-01-01

Stratigraphic investigations of fluvio-deltaic and lacustrine sediments exposed in stream cuts, quarry walls, and deep trenches east of the Sierra Nevada in Owens Valley near Lone Pine, California have enabled the reconstruction of pluvial Owens Lake level oscillations. Age control for these sediments is from 22 radiocarbon (14C) dates and the identification and stratigraphic correlation of a tephra, which when plotted as a function of age versus altitude, define numerous oscillations in the level of pluvial Owens Lake during the latest Pleistocene and early Holocene. We have constructed a lake-level altitude curve for the time interval ???27,000 cal yr BP to present that is based on the integration of this new stratigraphic analysis with published surface stratigraphic data and subsurface core data. Pluvial Owens Lake regressed from its latest Pleistocene highstands from ???27,000 to ???15,300 cal yr BP, as recorded by ???15 m of down cutting of the sill from the altitudes of ???1160 to 1145 m. By ???11,600 cal yr BP, the lake had dropped ???45 m from the 1145 m sill. This lowstand was followed by an early Holocene transgression that attained a highstand near 1135 m before dropping to 1120 m at 7860-7650 cal yr BP that had not been recognized in earlier studies. The lake then lowered another ???30 m to shallow and near desiccation levels between ???6850 and 4300 cal yr BP. Fluvial cut-and-fill relations north of Lone Pine and well-preserved shoreline features at ???1108 m indicate a minor lake-level rise after 4300 cal yr BP, followed by alkaline and shallow conditions during the latest Holocene. The new latest Quaternary lake-level record of pluvial Owens Lake offers insight to the hydrologic balance along the east side of the southern Sierra Nevada and will assist regional paleoclimatic models for the western Basin and Range. ?? 2005 Elsevier Ltd. All rights reserved.

The jellification of north temperate lakes

PubMed Central

Jeziorski, Adam; Tanentzap, Andrew J.; Yan, Norman D.; Paterson, Andrew M.; Palmer, Michelle E.; Korosi, Jennifer B.; Rusak, James A.; Arts, Michael T.; Keller, Wendel (Bill); Ingram, Ron; Cairns, Allegra; Smol, John P.

2015-01-01

Calcium (Ca) concentrations are decreasing in softwater lakes across eastern North America and western Europe. Using long-term contemporary and palaeo-environmental field data, we show that this is precipitating a dramatic change in Canadian lakes: the replacement of previously dominant pelagic herbivores (Ca-rich Daphnia species) by Holopedium glacialis, a jelly-clad, Ca-poor competitor. In some lakes, this transformation is being facilitated by increases in macro-invertebrate predation, both from native (Chaoborus spp.) and introduced (Bythotrephes longimanus) zooplanktivores, to which Holopedium, with its jelly coat, is relatively invulnerable. Greater representation by Holopedium within cladoceran zooplankton communities will reduce nutrient transfer through food webs, given their lower phosphorus content relative to daphniids, and greater absolute abundances may pose long-term problems to water users. The dominance of jelly-clad zooplankton will likely persist while lakewater Ca levels remain low. PMID:25411451

Distribution and abundance of burrowing mayflies (Hexagenia spp.) in Lake Erie, 1997-2005

USGS Publications Warehouse

Krieger, K.A.; Bur, M.T.; Ciborowski, J.J.H.; Barton, D.R.; Schloesser, D.W.

2007-01-01

Burrowing mayflies (Hexagenia limbata and H. rigida) recolonized sediments of the western basin of Lake Erie in the 1990s following decades of pollution abatement. We predicted that Hexageniawould also disperse eastward or expand from existing localized populations and colonize large regions of the other basins. We sampled zoobenthos in parts of the western and central basins yearly from 1997–2005, along the north shore of the eastern basin in 2001–2002, and throughout the lake in 2004. In the island area of the western basin, Hexagenia was present at densities ≤1,278 nymphs/m2and exhibited higher densities in odd years than even years. By contrast, Hexagenia became more widespread in the central basin from 1997–2000 at densities ≤48 nymphs/m2 but was mostly absent from 2001–2005. Nymphs were found along an eastern basin transect at densities ≤382/m2 in 2001 and 2002. During the 2004 lake-wide survey, Hexagenia was found at 63 of 89 stations situated throughout the western basin (≤1,636 nymphs/m2, mean = 195 nymphs/m2, SE = 32, N = 89) but at only 7 of 112 central basin stations, all near the western edge of the basin (≤708 nymphs/m2), and was not found in the eastern basin. Hexagenia was found at 2 of 62 stations (≤91 nymphs/m2) in harbors, marinas, and tributaries along the south shore of the central basin in 2005. Oxygen depletion at the sediment-water interface and cool temperatures in the hypolimnion are probably the primary factors preventing successful establishment throughout much of the central basin. Hexagenia can be a useful indicator of lake quality where its distribution and abundance are limited by anthropogenic causes.

Simulation of the shallow aquifer in the vicinity of Silver Lake, Washington County, Wisconsin, using analytic elements

USGS Publications Warehouse

Dunning, C.P.; Thomas, Judith Coffman; Lin, Yu-Feng

2003-01-01

A Silver Lake water budget was defined using both published hydrologic data and simulations using the calibrated model. Model simulations show that 1.08 cubic feet per second of ground water enters Silver Lake on the upgradient (primarily western) side and 0.08 cubic feet per second recharges to ground water on the downgradient (primarily eastern) side. Net precipitation (precipitation minus evaporation) on the lake is 0.04 cubic feet per second. Collectively, these water-budget terms provide a residual value of 1.04 cubic feet per second flow to Silver Creek at the north end of Silver Lake, which is a very good match to the range of measured flow (0.7 to 5.2 cubic feet per second). Ground-water recharge areas for Silver Lake are largely on the western side of the lake. The recharge area for the northern two-thirds of Silver Lake is west toward Big Cedar Lake. Assuming a porosity of 20 percent, model results indicate that the 50-year time-of-travel for recharge to Silver Lake does not extend to Big Cedar Lake. The recharge area for the southern one-third of Silver Lake is west toward Little Cedar Lake. Model results indicate that time of travel for recharge to Silver Lake from Little Cedar Lake is about 15 to 20 years. For travel times greater than 15 or 20 years, the ground-water recharge area for Little Cedar Lake and inflow from Big Cedar Lake also should be considered recharge affecting Silver Lake. Solute flux toward Silver Lake was calculated based on simulated ground-water flux and measured concentrations in the upgradient piezometers and observation wells.

Summary of biological investigations relating to water quality in the Western Lake Michigan Drainages, Wisconsin and Michigan

USGS Publications Warehouse

Scudder, B.C.; Rheaume, S.J.; Parsons, S.R.; Lenz, B.N.

1996-01-01

Most biological studies related to waterquality conditions in the Western Lake Michigan Drainages have focused on populations and community structure of aquatic biota. Chemical concentrations in tissues of aquatic biota have been the next most common area of research. Our review suggests a paucity of data related to the health of all types of aquatic biota, especially amphibians, invertebrates, and reptiles; toxicity studies also were relatively uncommon. Overall, organisms primarily studied have been fish and invertebrates, although birds are most frequently examined in studies of organism health. The Fox/ Wolf Subbasin has been the focus of many more studies than the other subbasins, most likely because of the greater extent and severity of known water-quality problems in the Lower Fox River/Green Bay area over the past several decades and because it is the largest subbasin. Studies in the other subbasins are needed to adequately assess the water quality of these areas.

Understanding three decades of land use changes and a cloudburst in Phewa Lake Watershed, Western Nepal

NASA Astrophysics Data System (ADS)

Sudmeier-Rieux, Karen; Tonini, Marj; Vulliez, Cindy; Sanjaya, Devkota; Derron, Marc-Henri; Jaboyedoff, Michel

2017-04-01

This paper details an extreme rainfall event, or cloudburst (315 mm/ 24 hours) which occurred on July 29-30, 2015 in the Phewa Lake Watershed, Western Nepal, three months after the April 25, 2015 Gorkha Earthquake. The event triggered over 170 landslides and debris flows, caused 8 deaths and considerable damage to livelihoods. The fatal debris flow started from one of the numerous rural roads, which have proliferated exponentially over the past decades. In addition to mapping landslides due to this extreme rainfall event, our study sought to document and analyze underlying natural and human land use factors that may have impacted the occurrence of landsliding (Vulliez et al submitted). To do so, our study analyzed land cover/ land use changes for the period 1979-2016 based on an interpretation of aerial photos and satellite images, combined with ground truthing. We studied how land use / land cover changes have resulted in a shift of active erosion zones from overgrazing around streams and forests to an exponential number of small failures along unplanned earthen rural roads, or "bulldozer roads". With several hundred small failures documented along roadsides (Leibundgut et al., 2016) as compared to only 14 landslides prior to 2015 extreme rainfall event - and none triggered by the 2015 earthquake - roads are thus a major driver of active erosion zones and small failures in the watershed. More effective management of the current unsustainable mode of rural road construction is required to reduce further environmental and economic impacts on vulnerable populations in Nepal. Leibundgut, G., Sudmeier-Rieux, K. Devkota, S., Jaboyedoff, M., Derron, M-H., Penna, I. Nguyen, L. (2016). Rural earthen roads impact assessment in Phewa watershed, Western region, Nepal. Geoenvironmental Disasters (2016) 3:13. DOI 10.1186/s40677-016-0047-8 Vulliez, C, Tonini, M., Sudmeier-Rieux, K. Devkota, S., Derron, M-H, Jaboyedoff, M. (submitted) Land use changes, landslides and roads in the

Thermal impacts of engineering activities and vegetation layer on permafrost in different alpine ecosystems of the Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Wu, Qingbai; Zhang, Zhongqiong; Gao, Siru; Ma, Wei

2016-08-01

Climate warming and engineering activities have various impacts on the thermal regime of permafrost in alpine ecosystems of the Qinghai-Tibet Plateau. Using recent observations of permafrost thermal regimes along the Qinghai-Tibet highway and railway, the changes of such regimes beneath embankments constructed in alpine meadows and steppes are studied. The results show that alpine meadows on the Qinghai-Tibet Plateau can have a controlling role among engineering construction effects on permafrost beneath embankments. As before railway construction, the artificial permafrost table (APT) beneath embankments is not only affected by climate change and engineering activities but is also controlled by alpine ecosystems. However, the change rate of APT is not dependent on ecosystem type, which is predominantly affected by climate change and engineering activities. Instead, the rate is mainly related to cooling effects of railway ballast and heat absorption effects of asphalt pavement. No large difference between alpine and steppe can be identified regarding the variation of soil temperature beneath embankments, but this difference is readily identified in the variation of mean annual soil temperature with depth. The vegetation layer in alpine meadows has an insulation role among engineering activity effects on permafrost beneath embankments, but this insulation gradually disappears because the layer decays and compresses over time. On the whole, this layer is advantageous for alleviating permafrost temperature rise in the short term, but its effect gradually weakens in the long term.

Detection of Critical LUCC Indices and Sensitive Watershed Regions Related to Lake Algal Blooms: A Case Study of Taihu Lake

PubMed Central

Lin, Chen; Ma, Ronghua; Su, Zhihu; Zhu, Qing

2015-01-01

Taihu Lake in China has suffered from severe eutrophication over the past 20 years which is partly due to significant land use/cover change (LUCC). There is an increasing need to detect the critical watershed region that significantly affects lake water degradation, which has great significance for environmental protection. However, previous studies have obtained conflicting results because of non–uniform lake indicators and inadequate time periods. To identify the sensitive LUCC indices and buffer distance regions, three lake divisions (Meiliang Lake, Zhushan Lake and Western Coastal region) and their watershed region within the Taihu Lake basin were chosen as study sites, the algal area was used as a uniform lake quality indicator and modeled with LUCC indices over the whole time series. Results showed that wetland (WL) and landscape index such as Shannon diversity index (SHDI) appeared to be sensitive LUCC indices when the buffer distance was less than 5 km, while agricultural land (AL) and landscape fragmentation (Ci) gradually became sensitive indices as buffer distances increased to more than 5 km. For the relationship between LUCC and lake algal area, LUCC of the WC region seems to have no significant effect on lake water quality. Conversely, LUCC within ML and ZS region influenced algal area of corresponding lake divisions greatly, while the most sensitive regions were found in 3 km to 5 km, rather than the whole catchment. These results will be beneficial for the further understanding of the relationship between LUCC and lake water quality, and will provide a practical basis for the identification of critical regions for lake. PMID:25642691

Toward an annual estimate of methane emissions from Lake Erie

NASA Astrophysics Data System (ADS)

Fernandez, J.; Townsend-Small, A.

2017-12-01

Lake Erie is the shallowest, warmest, and most eutrophic of all of the North American Great Lakes. The central basin of Lake Erie exhibits seasonally hypoxic bottom waters, which contributes to biological methane (CH4) production. Leaks from extensive natural gas wells and pipelines in Canadian waters are a potential source of thermogenic CH4 to the lake. The shallow western basin lacks water column hypoxia, but experiences increasingly frequent algal blooms and hypoxic sediments. Our past research, focused on the central basin, indicated that Lake Erie is a positive source of CH4 during late summer (August - September), emitting 1.3 ± 0.6 × 105 kg CH4-C day. Here, we present a seasonal dataset of CH4 fluxes measured throughout a 16-month period starting in the spring of 2015 and ending late summer in 2016 to estimate an annual lake wide CH4 emission. Our results indicate that the western basin experienced the greatest CH4 emissions, and the highest rates of CH4 flux co-occur with the highest rates of nutrient loading and largest algal blooms near the mouth of the Maumee River. Winter CH4 fluxes were minimal and similar throughout the lake, indicating that natural gas wells are a minimal source of CH4 emissions. Emissions were highest in August and tapered off through the fall and winter, rising again in spring. The estimated annual CH4 emission in Lake Erie was 4.41 × 107 kg CH4-C yr-1. We compared this to other CH4 sources in Michigan and Ohio in the USEPA Greenhouse Gas Reporting Program Database, and found that Lake Erie is second largest emitter of CH4 in Ohio (a landfill in Cincinnati is a larger source), and the largest in Michigan. Recent work has shown that eutrophication in lakes such as Lake Erie may be on the rise due to climate change induced increases in precipitation. If so, these large CH4 emissions may have positive feedback consequences to climate warming. Therefore, more research is needed to indicate whether or not these CH4 emissions are

Nonlinear Dynamics of the Nearshore Boundary Layer of a Large Lake (Lake Geneva)

NASA Astrophysics Data System (ADS)

Cimatoribus, Andrea A.; Lemmin, U.; Bouffard, D.; Barry, D. A.

2018-02-01

We examine nearshore and pelagic current variability in Lake Geneva, a large and deep lake in western Europe, using observations from several measurement locations and a three-dimensional numerical model for the period 2014-2016. Linear internal seiche modes excited by wind forcing clearly appear as peaks in the energy spectra for measurements in offshore locations. In contrast, spectra from the nearshore data, where currents interact with the lake bed, reveal a negligible contribution of internal seiches to the total kinetic energy. A similar contrast is seen in the spectra obtained from the numerical model at the same locations. Comparing the contribution of the different terms in the vertically averaged momentum equation from the modeling results shows that the nonlinear advective term dominates in the nearshore boundary layer. Its contribution decays with distance from shore. The width of this nearshore boundary layer, which may extend for several kilometers, seems to be mainly determined by local topography. Both field measurements and modeling results indicate that nonlinear dynamics are of primary importance in the nearshore boundary layer.