Artemia in the Salt Lakes of Russia:the Productivity of Populations,the Reserves of the Cysts and the Fisheries

Artemia cysts are an extremely important component of aquaculture diets.It is well established that the cultivation of fish and shellfish derive substantial health and growth advantages when Artemia are included in the diets of the

The changes of pigment contents and their environmental implications in the lake sediments of Ny-lesund,Svalbard,the Arctic

According to palaeoclimatic and modern instrumental data,numerous studies have indicated that the Arctic climate has undergone a significant warming during the past 100 years,and this may lead to significant impact on the fragile lake ecosystem.In this study,we collected a lake sediment core from the Nylesund of Svalbard and determined the concentrations of four pigments including chlorophyll derivatives,total carotenoids,oscillaxanthin and myxoxanthophyll in the sediments.Combined with other physical and chemical proxies such as calcium carbonate,total organic carbon,biogenic silicon etc.,we have reconstructed the historical changes of lacustrine primary productivity in Ny-lesund,especially for the past 100 years.The results showed that during the period of Little Ice Age（LIA）,the climate was unfavorable for the growth of the lake algae,and thus the lacustrine productivity declined.This result was supported by the relatively low contents of pigment and biogenic silica in the sediments.In contrast,the contents of total organic carbon（TOC） and sediment pigments increased significantly in the upper 5 cm（-1890AD）,reflecting the rapid growth of the lake algae,thus the great increase of lacustrine primary productivity,corresponding to the warming climate after LIA.However,the biogenic silica in the upper sediments still had a relatively low level,and this might be related to the growth competition with other algae species.Over the past 100 years,the ratio of Osc/Myx in the sediments decreased continuously,indicative of durative increase of myxoxanthophyll in blue-green algal pigments,and this might imply that the human activity had enhanced the nutrition level of the lake in the Arctic region.

Intercalation Assembly and Chemical Product Engineering of Layered Intercalated Functional Materials Based on Efficient Utilization of Magnesium Resources in Salt Lakes

1 Introduction Magnesium salts are very important by-product of salt lake industry in West China.Nearly 200 million cubic meters of waste brine are released to the environment

Primary Production and the Hydrochemical Parameters of the Salt Lakes in the North-Western Part of the Crimea(Russia)

1 Introduction It is known that more than 300 lakes and lagoons are present in the Crimean Peninsula,which are divided depending on position to 7 groups:Perekop,Tarkhankut,Evpatoriyskaya,Khersonesskaya,lake on the mountainpastures,Kerch and Genicheskaya.Almost the all lakes,with the exception of the small freshwater lakes,which situated on mountain pastures of the Main ridge of

A 60-year sedimentary record of natural and anthropogenic impacts on Lake Chenghai,China

Recent sediments from Lake Chenghai, China, were investigated at high temporal resolution to trace both natural and anthropogenic effects on the lake using total organic carbon （TOC）, total nitrogen （TN）, total phosphorus （TP）, organic phosphorus （Po）, inorganic phosphorus （Pi） and organic carbon and nitrogen stable isotopes （~13Corg and 615N） in a 137Cs-dated sediment core. The results indicated that the sedimentary record covers the last 60 years, during which the lake had undergone apparent changes in nutrient sources and productivity in response to nutrient loading. Prior to the late 1980s, the nutrient contents in sediments mainly originated from algae and lake productivity was relatively stable. Since the late 1980s, increasing TOC, TN and TP concentrations together with the change of 613Corg and 615N suggested anthropogenic perturbations in nutrient loading and lake productivity. Endogenic nutrients derived from algae and anthropogenic inputs were two important sources of sedimentary nutrients. The anthropogenic nutrients mainly originated from the discharge of industrial wastewater and artificial cultivation of Spirulina after the middle 1980s, and domestic wastewater discharged from Yongsheng County since 1993.

Investigation of low-molecular weight organic acids and their spatiotemporal variation characteristics in Hongfeng Lake,China

The identities and concentrations of low-molecular-weight organic acids （LMWOAs） were determined by ion chromatography throughout a 20-m water column in Hongfeng Lake, China. The spatiotemporal variations of LMWOAs and their contributions to dissolved organic matter （DOM） in a research period of 24 hr were also investigated. The results demonstrated that five LMWOAs （lactic, acetic, pyruvic, sorbic, oxalic acid） were detected, and their total concentration and proportion in DOC were 6.55 μmol/L and 7.47%. Their average levels were 2.50, 0.65, 2.35, 0.96 and 0.09 μmol/L, respectively. LMWOAs were higher during daytime （10：00-18：00 on Jun 13, 2008） than nighttime （21：00-6：00 the next morning）, in particular 4.99 μmol/L high in the epilimnion （ 1 m water depth）, reflecting the fact that direct import from terrigenous sources and photochemical production from humic materials were dominant during LMWOAs＇ origin and accumulation. The same factors caused LMWOAs to be 0.63 μmol/L in the epilimnion higher than in the hypolimnion. The rapid decrease of total organic acid （TOA） up until 18：00 mainly resulted from bio-uptake and mineralization in the hypolimnion （〉1 m water depth）. Pyruvic acid increased with time in the epilimnion and decreased in the hypolimnion, largely related to the two contrary processes of continuous degradation and synthesis of macromolecular organic matter during life materials＇ cycle mediated by organisms. Simultaneously, plankton behavior and thermal stratification played a pivotal role in LMWOAs＇ behavior in the water column, causing decreasing and increasing profiles. The distribution of LMWOAs represents an interesting resource for biogeochemical research of DOM in aquatic ecosystems.

Dust storms in northern China and their significance for the concept of the Anthropocene

A key scientific issue in the study of the Anthropocene is the determination of the corresponding stratigraphic marker in geological archives.The arid and semi-arid regions of Asia are the second largest dust source on Earth,and their release,transport and deposition of dust affect global climate change,as well as marine and terrestrial biogeochemical cycles.Over the past~2000 years,human activity has outpaced natural climatic variability as the dominant control of dust storms in northern China.Thus,exploring the potential of anthropogenic Asian dust as a marker of the Anthropocene and its impacts on lake ecosystems may contribute to an improved definition of the characteristics and timing of the Anthropocene.In this context,we measured spectrally-inferred chlorophyll a from the sediments of an undisturbed alpine lake in northern China,and compared the results with dust storm data from the same cores and with regional climatic records.Asian dust is a widely distributed,globally significant signal of human activity,and it is also well preserved in various geological archives;hence,we propose anthropogenic dust can be considered as a potential marker of the Anthropocene.Anthropogenic dust signals in stratigraphic records during the past~2000 years differ substantially from those during the early and middle Holocene,which demonstrates that,at least since~2000 years ago,human activity has exceeded the natural forcing of dust transport in northern China.We therefore propose that there are spatial and temporal differences in the onset of the Anthropocene,as defined by anthropogenic dust deposition,which is therefore time-transgressive.Our spectrally-inferred chlorophyll a record is consistent with dust storm activity over the past~2000 years(except since the 1950s),suggesting that anthropogenic dust storms were the dominant control on lake primary production.Prior to the 1950s the interactions of the East Asian summer monsoon(EASM),human activity,dust storms and lake ecosystems resulted in a shift from a pattern in which“human activity outpaced the EASM as the dominant control on the Earth surface system”to one in which,after the 1950s,“human activity became the dominant factor influencing the EASM and the Earth surface system”.In the future this pattern may trend towards one in which there is the“sustainable development of humans and the environment”.We suggest that,in order to better understand the interactions of human activity,climate and environment,future research on the Anthropocene should focus on its time-transgressive characteristics and regional differences,in addition to the“Great Acceleration”