Freshwater ecosystem | EPFL Graph Search

Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes, ponds, rivers, streams, springs, bogs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats can be classified by different factors, including temperature, light penetration, nutrients, and vegetation. There are three basic types of freshwater ecosystems: Lentic (slow moving water, including pools, ponds, and lakes), lotic (faster moving water, for example streams and rivers) and wetlands (areas where the soil is saturated or inundated for at least part of the time). Freshwater ecosystems contain 41% of the world's known fish species. Freshwater ecosystems have undergone substantial transformations over time, which has impacted various characteristics of the ecosystems. Original attempts to understand and monitor freshwater ecosystems were spurred on by threats to human health (for example cholera outbreaks due to sewage c

Hydrological Importance and Water Quality Treatment Potential of a Small Freshwater Wetland in the Humid Tropics of Costa Rica

Manon Bachelin

Rapid increases in population and growing food demand are causing widespread deterioration of tropical wetlands globally, and an increased focus on the role and function of these imperiled ecosystems is required. Objectives of this study were to investigate the hydrological dynamics and water quality treatment potential of a small freshwater wetland in the humid tropics of Costa Rica. High-resolution, spatially distributed surface water and meteorological data were combined with a detailed topographical survey to quantify the wetland water balance, hydroperiod, and seasonal variability of wetland area, volume, and residence time. The water balance was dominated by precipitation and outflow, with little contribution from runoff, except during the largest storms. Over 80% of the wetland was flooded continuously; hydroperiods in remaining areas were bi-modal. Small seasonal variations in wetland area, volume, and residence times yielded high and sustained water quality treatment potential. Potential pollutant removal efficiencies were 63.6-99.8% for biological oxygen demand; 60.0-99.8% for total suspended solids; 51.1-98.5% for total nitrogen; and 34.2-99.7% for total phosphorous. The study provides insights into the hydrological functions of this and similar small Central American wetlands and provides a template for extending in-depth hydrological monitoring to other tropical wetland sites.

2011

Development and implementation of eco-genomic tools for aquatic ecosystem biomonitoring: the SYNAQUA French-Swiss program

Régis Lionel Vivien

The effectiveness of environmental protection measures is based on the early identification and diagnosis of anthropogenic pressures. Similarly, restoration actions require precise monitoring of changes in the ecological quality of ecosystems, in order to highlight their effectiveness. Monitoring the ecological quality relies on bioindicators, which are organisms revealing the pressures exerted on the environment through the composition of their communities. Their implementation, based on the morphological identification of species, is expensive because it requires time and experts in taxonomy. Recent genomic tools should provide access to reliable and high-throughput environmental monitoring by directly inferring the composition of bioindicators' communities from their DNA (metabarcoding). The French-Swiss program SYNAQUA (INTERREG France-Switzerland 2017-2019) proposes to use and validate the tools of environmental genomic for biomonitoring and aims ultimately at their implementation in the regulatory bio-surveillance. SYNAQUA will test the metabarcoding approach focusing on two bioindicators, diatoms, and aquatic oligochaetes, which are used in freshwater biomonitoring in France and Switzerland. To go towards the renewal of current biomonitoring practices, SYNAQUA will (1) bring together different actors: scientists, environmental managers, consulting firms, and biotechnological companies, (2) apply this approach on a large scale to demonstrate its relevance, (3) propose robust and reliable tools, and (4) raise public awareness and train the various actors likely to use these new tools. Biomonitoring approaches based on such environmental genomic tools should address the European need for reliable, higher-throughput monitoring to improve the protection of aquatic environments under multiple pressures, guide their restoration, and follow their evolution.

SPRINGER HEIDELBERG2018

Direct determination of niobium at the low nanogram level in mineral waters and freshwaters

Michaël Bensimon, Montserrat Filella, David-Julien Magnenat

The increasing use of elements such as Nb and Ta in green and information technologies makes it necessary to develop appropriate analytical methods for studying their environmental and ecotoxicological behaviour. This paper describes the first time Nb has been directly identified in mineral and freshwaters, using inductively coupled plasma sector field mass spectrometry (ICP-SFMS). The scant values of Nb concentrations in freshwaters published include many values which are very close, or directly below, the detection limit of the technique used; when low values are reported, the techniques used often include solid phase extraction preconcentration; with the associated difficulty in obtaining low blanks and risk of incomplete resin desorption. We analysed 20 water samples of contrasting characteristics along with certificate reference material SLRS-5. Values detected ranged from 0.3 to 12 ng L-1. No sample was below the detection limit. Our results show that the determination of Nb by ICP-SFMS is possible, although it is not a routine analysis (i.e., it requires excellent blanks and machine response stability). These results are consistent with existing information. Currently, Nb ecotoxicological characteristics and behaviour in environmental compartments are essentially unknown; the possibility of directly determining Nb at these concentrations opens up new avenues for studying this element at meaningful environmental levels.

Royal Society of Chemistry2014

Development and implementation of eco-genomic tools for aquatic ecosystem biomonitoring: the SYNAQUA French-Swiss program

Régis Lionel Vivien

SPRINGER HEIDELBERG2018