Search results for "lake ecosystem"

Generalist invasion in a complex lake food web

2023

Invasive species constitute a threat not only to native populations but also to the structure and functioning of entire food webs. Despite being considered as a global problem, only a small number of studies have quantitatively predicted the food web-level consequences of invasions. Here, we use an allometric trophic network model parameterized using empirical data on species body masses and feeding interactions to predict the effects of a possible invasion of Amur sleeper (Perccottus glenii), on a well-studied lake ecosystem. We show that the modeled establishment of Amur sleeper decreased the biomasses o ftop predator fishes by about 10%–19%. These reductions were largely explained by inc…

Drivers of change and ecosystem status in a temperate lake over the last Post-Glacial period from 14.5 kyr

2020

AbstractUnderstanding the long-term dynamics of ecological communities on the centuries-to-millennia scale is important for explaining present-day biodiversity patterns. Placing these patterns in a historical context could yield reliable tools for predicting possible future scenarios. Paleoarchives of macro+ and micro-fossil remains, and most importantly biomarkers such as fossil pigments and ancient DNA present in various sedimentary deposits, allow long term changes in ecological communities to be analysed. We use recent compilations of data including fossil pigments, metabarcoding of sedimentary ancient DNA and microfossils together with data analysis to understand the impact of gradual …

Hydrology is reflected in the functioning and community composition of methanotrophs in the littoral wetland of a boreal lake

2010

In lake ecosystems a major proportion of methane (CH4) emissions originate from the littoral zone, which can have a great spatial variability in hydrology, soil quality and vegetation. Hitherto, spatial heterogeneity and the effects it has on functioning and diversity of methanotrophs in littoral wetlands have been poorly understood. A diagnostic microarray based on the particulate methane monooxygenase gene coupled with geostatistics was used to analyse spatial patterns of methanotrophs in the littoral wetland of a eutrophic boreal lake (Lake Kevaton, Eastern Finland). The wetland had a hydrology gradient with a mean water table varying from −8 to −25 cm. The wettest area, comprising the h…

Ostracod palaeolimnological analysis reveals drastic historical changes in salinity, eutrophication and biodiversity loss in a coastal Mediterranean …

2013

The Albufera of Valencia, one of the largest oligohaline coastal lagoons of the Iberian Peninsula, has suffered hydrological and landscape modifications since medieval times. This paleolimnological study clears up the controversy about the factors, which drove the lake to its present state. Lithological descriptions, ostracod paleoassemblages and Cyprideis torosa (Jones, 1850) shell morphological variations and geochemistry (δ18O, δ13C and Sr/Ca) have been used to reconstruct the lake ecosystem evolution during the last two centuries. The sandy sediments at the bottom of L’Antina core (63 cm) presented a typical assemblage of brackish water ostracods, with shell-derived δ18O values, inferre…

Assessment of the Pressure Level over Lentic Waterbodies through the Estimation of Land Uses in the Catchment and Hydro-Morphological Alterations: Th…

2021

The features of lentic waterbodies largely depend on the surrounding environment. Mediterranean coastal lagoons have been historically altered, with their catchment being highly modified for agricultural, livestock, or urban uses. Changes in land uses induce pressures that impact the waterbodies and alter their ecological status. The objectives of this paper were: to develop a methodological approach (LUPLES: Land Uses for estimating Pressure Levels to approach the Ecological Status), to quantify the main pressures on the waterbodies and to forecast the possible impacts of these pressures on their ecological status. Corine-Land Cover maps and Geographic Information System technics were used…

Genetic and Environmental Controls on Nitrous Oxide Accumulation in Lakes

2015

We studied potential links between environmental factors, nitrous oxide (N2O) accumulation, and genetic indicators of nitrite and N2O reducing bacteria in 12 boreal lakes. Denitrifying bacteria were investigated by quantifying genes encoding nitrite and N2O reductases (nirS/nirK and nosZ, respectively, including the two phylogenetically distinct clades nosZ(I) and nosZ(II)) in lake sediments. Summertime N2O accumulation and hypolimnetic nitrate concentrations were positively correlated both at the inter-lake scale and within a depth transect of an individual lake (Lake Vanajavesi). The variability in the individual nirS, nirK, nosZ(I), and nosZ(II) gene abundances was high (up to tenfold) a…

Within-lake variability in carbon and nitrogen stable isotope signatures

2006

SUMMARY 1. We assessed spatial and temporal variation in carbon and nitrogen isotopic signatures in different compartments of a single lake ecosystem. Stable isotope analyses were made on samples of particulate organic matter (POM), zooplankton, periphyton, macrophytes, macroinvertebrates and fish collected from several locations throughout the ice-free period. 2. No spatial variation in d 13 Co rd 15 N values was found for pelagic samples of POM and zooplankton. However, pelagic d 15 N signatures increased steadily through the summer resulting in an almost 6& average increase in POM and zooplankton. A concurrent decrease in epilimnetic nitrate concentrations suggested that the increase in …

Corrigendum to “Climate variability and lake ecosystem responses in western Scandinavia (Norway) during the last Millennium” [Palaeogeogr. Palaeoclim…

2020

Environmental history of an urban lake: a palaeolimnological study of Lake Jyväsjärvi, Finland

2003

Sedimentary diatom frustules and chironomid remains, in addition to the chemical stratigraphy of 32 elements and organic pollutants such as resin acids, PCB, DDT and its metabolites, were studied from core samples taken from Lake Jyvasjarvi in Central Finland (64° 14′ N, 25° 47′ E). The sediment profile covered over 200 years, with the oldest samples representing a period of very low human interference. The town of Jyvaskyla was established on the lake shore in 1837, and the lake received untreated municipal wastewater from the town up until, 1977. A paper mill started operations in 1872 and began discharging effluent into Lake Jyvasjarvi. In recent years this effluent loading has been redu…

Parameter Sensitivity and the Quality of Model Predictions

1994

Using SIM-PEL, a comprehensive model for the pelagic compartment of lake ecosystems, we analyse synergistic toxicant effects in lake ecosystems. We show, that — even for a rather simple model — model predictions may be strongly dependent on the time horizon of the prediction and on the quality of input parameters. For longer time spans, small errors in parameter estimation may lead to qualitatively wrong prediction of toxicant effects. Monte Carlo simulations allow to take errors in parameter estimation into account, but they need rather good estimates of parameter variance.