Journal of Limnology最新文献

{"title":"A snapshot of alien cyanobacteria found in northeastern European freshwaters - Lithuania case","authors":"Izabelė Šuikaitė, J. Karosienė, J. Koreivienė","doi":"10.4081/jlimnol.2024.2183","DOIUrl":"https://doi.org/10.4081/jlimnol.2024.2183","url":null,"abstract":"In recent years, cyanobacterial invasions have increased in European temperate lakes. Climate warming is highlighted as a key driver of the distribution and establishment of alien cyanobacteria, and water bodies in poor ecological status, characterized by meso-eutrophic conditions, are underlined as a suitable habitat for invasion. The establishment of newly arrived species is directly related to fluctuating physicochemical factors such as temperature, and nutrient concentrations, especially phosphorus and nitrogen, or biotic factors such as competition. Cyanobacterial invasions can have profound ecological impacts, such as displacing native species, causing the biodiversity loss of local communities, and modifying the ecosystem’s cyanotoxins profile. This study presents the occurrence of four alien bloom-forming potentially toxic cyanobacteria - Chrysosporum bergii, Cuspidothrix isstaschenkoi, Raphidiopsis raciborskii and Sphaerospermopsis aphanizomenoides - in the northern parts of their current range in temperate Europe and provides insights into their ecology. Special attention was paid to the lakes of Lithuania (Simnas, Jieznas and Gineitiškės), which is the northernmost location of distribution zone for some alien cyanobacteria and provides as a dispersion route to Norther Europe via the continental area. We i) described dynamics of indigenous cyanobacteria community invaded by alien cyanobacteria; ii) assessed concentrations of cyanotoxins in field and culture samples, and suggested toxin producers; and iii) detailed the correlation between the biomass of alien cyanobacteria and environmental conditions. These species were found in three human-affected shallow hyper-eutrophic lakes during warm period of the year; however, their biomass was low. We assume that present temperatures do not limit the occurrence of these alien species but are insufficient for their successful proliferation. In addition, we provided the first evidence of anatoxin-a production by isolated strains of C. issatschenkoi in Lithuania. Alien cyanobacteria were detected at an early stage of their development, however, a rise in global temperatures and the spread of strains with toxigenic potential could lead to increased proliferation and further northward expansion of these alien species.","PeriodicalId":509392,"journal":{"name":"Journal of Limnology","volume":"18 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140980842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sediment biomarkers record hydrological and anthropogenic-driven environmental changes since 1800 AD in the Ili-Balkhash Basin, arid Central Asia","authors":"Hongliang Zhang, Jinglu Wu, Long Ma, Shuie Zhan, Miao Jin, Zhangdong Jin","doi":"10.4081/jlimnol.2024.2106","DOIUrl":"https://doi.org/10.4081/jlimnol.2024.2106","url":null,"abstract":"Human activity and hydroclimate change greatly influence the environment in a lake and its catchment, particularly in areas with fragile ecosystems, such as arid Central Asia. In this study, lipid biomarkers (n-alkanes and n-fatty acids) were measured in a 210Pb- and 137Cs-dated sediment core from Lake Balkhash to determine their environmental significance and infer the history of environmental change over the last ~200 years. The terrestrial origin of long-chain n-alkanes and the aquatic origin of both n-fatty acids and mid-/short-chain n-alkanes were inferred from molecular distributions and diagnostic ratios. Three major environmental phases were identified over the past two centuries based on stratigraphic shifts in biomarker indicators. During 1800-1860 AD, the lake exhibited a high-water level with abundant submerged/floating macrophytes and limited phytoplankton, as suggested by multiple indicators, e.g., high proportions of aquatic macrophytes (Paq) and long-chain n-fatty acids (L-FAs). Overall, minor terrestrial inputs were revealed by low concentrations of long-chain n-alkanes (L-ALKs), suggesting dense vegetation cover in the catchment. The lake environment experienced a pronounced change in the subsequent phase from 1860–1930 AD, during which the cover of submerged/floating macrophytes gradually diminished, as revealed by the decreasing trend of aquatic proxies, e.g., L-FAs and Paq. In contrast, the number of emergent plants and terrestrial inputs increased, as suggested by the decreased Paq values. A great variation in water levels likely resulted in the shrinkage of the submerged/floating macrophyte cover. During 1930-2017 AD, anthropogenic impacts began to appear on the sediment profile. The highest terrestrial inputs, as revealed by the maximum L-ALK abundance on record, indicated intensive exploitation of the catchment during 1935-1959 AD. The lowest L-FA and Paq values suggested that submerged/floating macrophytes were at the lowest levels during this phase, possibly in response to the decreased water levels and increasing salinity. Increased human-induced nutrient loading coupled with elevated regional temperature prompted the lake to become an increasingly productive lake system, especially in more recent decades, as indicated by the highest levels of short-chain lipids. These results highlight the important role of hydrological variation and human activity in the environmental evolution of the Ili-Balkhash Basin.","PeriodicalId":509392,"journal":{"name":"Journal of Limnology","volume":"24 8‐9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140426309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How the catchment-river-lake continuum shapes the downstream water quality","authors":"S. Vilbaste, P. Pall, M. Haldna, P. Nõges, K. Piirsoo, T. Nõges","doi":"10.4081/jlimnol.2024.2167","DOIUrl":"https://doi.org/10.4081/jlimnol.2024.2167","url":null,"abstract":"Lakes play a crucial role in the nutrient cycling of Earth, despite covering only a small fraction of the planet’s surface. Their interactions with their surrounding catchment areas significantly impact ecosystems and regulatory services. The connection between a lake and its catchment, especially the drainage ratio (catchment area to lake surface area), shapes the characteristics of lakes and their response to catchment processes. Within the catchment area, geological, land cover, and land use factors influence the composition of stream water that flows into the lake. These factors play a role in transporting various substances, both organic and inorganic, to the streams. Lakes act as dynamic filters, altering the chemical composition of water that flows through them. This study aims to investigate how a large, shallow lake impacts the quality of the river water as it passes through. It builds on an analysis of nutrient (carbon, nitrogen, phosphorus, silicon) fluxes into Lake Võrtsjärv, using six years of monthly monitoring data from five main inflows and the outflow. The research explores how catchment characteristics and hydrology affect nutrient concentrations and loadings into the lake, as well as the retention or release of substances by the lake. Findings reveal that catchment characteristics, such as land use and forest cover, significantly influence water quality parameters. Different inflows showed variations in water quality, and annual variations were observed, largely correlated with precipitation and discharge. Võrtsjärv plays a critical role in retaining or releasing nutrients, with varying impacts depending on the water budget of the lake. In years with a positive water balance, the lake retains all nutrients, whereas in dry years only inflowing N and P loads exceed their outflow. Overall, this study underscores the importance of lakes as integral components of catchment ecosystems, shedding light on their complex interactions with the environment and the implications for water quality. It emphasizes the need for careful consideration of land use and hydrological factors in managing and preserving these vital aquatic systems.","PeriodicalId":509392,"journal":{"name":"Journal of Limnology","volume":"754 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140479502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}