Macroinvertebrate distribution and aquatic ecology in the Ruoergai （Zoige） Wetland, the Yellow River source region

The Ruoergai （Zoige） Wetland, the largest plateau peatland in the world, is located in the Yellow River source region. The discharge of the Yellow River increases greatly after flowing through the Ruoergai Wetland. The aquatic ecosystem of the Ruoergai Wetland is crucial to the whole Yellow River basin. The Ruoergai wetland has three main kinds of water bodies： rivers, oxbow lakes, and marsh wetlands. In this study, macro- invertebrates were used as indicators to assess the aquatic ecological status because their assemblage structures indicate long-term changes in environments with high sensitivity. Field investigations were conducted in July, 2012 and in July, 2013. A total of 72 taxa of macroinvertebrates belonging to 35 families and 67 genera were sampled and identified. Insecta was the dominant group in the Ruoergai Basin. The alpha diversity of macroinvertebrates at any single sampling site was low, while the alpha diversity on a basin-wide scale was much higher. Macroinvertebrate assemblages in rivers, oxbow lakes, and marsh wetlands differ markedly. Hydrological connectivity was a primary factor causing the variance of the bio-community. The river channels had the highest alpha diversity of macroinvertebrates, followed by marsh wetlands and oxbow lakes. The density and biomass of Gastropoda, collector filterers, and scrapers increased from rivers to oxbow lakes and then to marsh wetlands. The fiver ecology was particular in the Ruoergai Wetland with the high beta diversity ofmacroinvertebrates, the low alpha diversity of macroinvertebrates, and the low taxa richness, density, and biomass of EPT （Ephemeroptera, Plecoptera, Trichoptera）. To maintain high alpha diversity of macro-invertebrates in the Ruoergai Wetland, moderate connec- tivity of oxbow lakes and marsh wetlands with rivers and measures to control headwater erosion are both crucial.

SINO-GERMAN COOPERATIVE RESEARCHES ON AQUATIC ECOTOXICOLOGY AND ECOLOGICAL CHEMISTRY

China has a huge population with relatively poor freshwater resources.With the development of industry and the explosion of its urban population,a great deal of industrial waste water containing various chemicals and untreated urban sewage has been discharged into rivers and lakes and caused severe contamination of many freshwater resources.The deterioration of the aquatic environment has affected the quality of drinking water, fishery and agricultural irrigation.It is estimated that by the 21st century,there will be a shortage of freshwater resources,which arc indispensable to human life, and the future shortage of freshwater

Florida Springs--A Water-Budget Approach to Estimating Water Availability

Florida＇s artesian springs receive groundwater outflows from the Floridan Aquifer System and are concentrated north of I-4 and west to the Florida Panhandle. These springs and their resulting spring runs support a unique freshwater ecology dependent on perennial flows, constant temperature and chemistry, and high light transmissivity. Numerous observations indicate that Florida＇s springs flows are declining as a result of the increasing extraction of groundwater for human uses. North Florida＇s karst environment is especially susceptible to nitrogen pollution from agricultural and urban development. An empirical springs/aquifer water budget is needed to better understand these spring stressors. Discharge data from 393 of the state＇s 1,000＋ artesian springs are used to estimate trends in total spring discharge by decade since 1930-39. This analysis indicates that average spring flows have declined by about 32%. Large groundwater pumping centers are altering spring flows over the whole springs region. Existing groundwater pumping rates from the Floridan Aquifer in 2010 were more than 30% of average annual aquifer recharge, and allocated groundwater use in north-central Florida is nearly double current estimated uses. Based on biological research conducted in Florida springs, these flow reductions are from two to six times greater than declines known to result in significant harm to aquatic resources.

A bacteria-based index of biotic integrity indicates aquatic ecosystem restoration

Intensive ecological interventions have been carried out in highly polluted shallow lakes to improve their environments and restore their ecosystems.However,certain treatments,such as dredging polluted sediment and stocking fish,can impact the aquatic communities,including benthos and fishes.These impacts can alter the composition and characteristics of aquatic communities,which makes community-based ecological assessments challenging.Here we develop a bacteria-based index of biotic integrity(IBI)that can clearly indicate the restoration of aquatic ecosystems with minimal artificial interventions.We applied this method to a restored shallow lake during 3-year intensive ecological interventions.The interventions reduced nutrients and heavy metals by 27.1%and 16.7%in the sediment,while the total organic carbon(TOC)increased by 8.0%due to the proliferation of macrophytes.Additionally,the abundance of sulfur-related metabolic pathways decreased by 10.5%as the responses to improved ecosystem.The score of bacteria-based IBI,which is calculated based on the diversity,composition,and function of benthic bacterial communities,increased from 0.62 in 2018 to 0.81 in 2021.Our study not only provides an applicable method for aquatic ecological assessment under intensive artificial interventions but also extends the application of IBI to complex application scenarios,such as ecosystems with significantly different aquatic communities and comparisons between different basins.

Analysis of microplastics in spring water

Springs are crucial as primary water sources for various human needs,including in Batu City,East Java,Indonesia.Preserving the integrity of these springs is essential to protect them from contamination,including emerging pollutants such as microplastics,which have been reported in aquatic ecosystems.Therefore,it is vital to analyze the presence of microplastics in springs to mitigate pollution.However,there is a lack of studies reporting the content of microplastics in springs,particularly in Batu City.This study aims to analyze microplastics in multiple springs within Batu City using a descriptive research method.The research materials encompass the abundance and characteristics of microplastics and various water quality parameters such as dissolved oxygen,pH,temperature,turbidity,color,total dissolved solids,taste,odor,and current velocity.Sampling was conducted at six springs in Batu City:Sumber Ngesong,Sumber Banyuning,Sumber Gemulo,Sumber Torong Belok,Sumber Kasinan,and Sumber Dari.The findings of this study indicate that the water quality in the springs of Batu City complies with established standards.However,microplastics were detected in all the sampled springs,with concentrations ranging from 208 to 354 particles/m^(3).The identified microplastics primarily included fibers,films,and fragments.MP polymers obtained in this study were Nylon,Low-Density Polyethylene(LDPE),Polyethylene terephthalate(PETE),and Polyvinyl chloride(PVC).Based on the study results,while the water in the spring area of Batu City meets water quality standards,it is necessary to implement mitigation measures to address the emerging pollutant pollution,such as microplastics,to safeguard the springs as a vital water source for human life.To the best of our knowledge,this study is the first to report the characteristics of microplastics in the springs of Batu City.

Electrogenic sulfur oxidation mediated by cable bacteria and its ecological effects

At the sediment-water interfaces,filamentous cable bacteria transport electrons from sulfide oxidation along their filaments towards oxygen or nitrate as electron acceptors.These multicellular bacteria belonging to the family Desulfobulbaceae thus form a biogeobattery that mediates redox processes between multiple elements.Cable bacteria were first reported in 2012.In the past years,cable bacteria have been found to be widely distributed across the globe.Their potential in shaping the surface water environments has been extensively studied but is not fully elucidated.In this review,the biogeochemical characteristics,conduction mechanisms,and geographical distribution of cable bacteria,as well as their ecological effects,are systematically reviewed and discussed.Novel insights for understanding and applying the role of cable bacteria in aquatic ecology are summarized.

Ecological variation along the salinity gradient in the Baltic Sea Area and its consequences for reproduction in the common goby

Although it has become clear that sexual selection may shape mating systems and drive speciation, the potential constraints of environmental factors on processes and outcomes of sexual selection are largely unexplored. Here, we investigate the geographic variation of such environmental factors, more precisely the quality and quantity of nest resources （bivalve shells） along a salinity gradient in the Baltic Sea Area （Baltic Sea, Sounds and Belts, and Kattegat）. We further test whether we find any salinity-associated morphological differences in body size between populations of common gobies Pomatoschistus microps, a small marine fish with a resource-based mat- ing system. In a geographically expansive field study, we sampled 5 populations of P. microps occurring along the salinity gradient （decreasing from West to East） in the Baltic Sea Area over 3 consecutive years. Nest resource quantity and quality decreased from West to East, and a correla- tion between mussel size and male body size was detected. Population density, sex ratios, mating- and reproductive success as well as brood characteristics also differed between populations but with a less clear relation to salinity. With this field study we shed light on geographic variation of distinct environmental parameters possibly acting on population differentiation. We provide insights on relevant ecological variation, and draw attention to its importance in the framework of context-dependent plasticity of sexual selection.