Search results for "benthic"

Mercury in fishes from Augusta Bay (southern Italy): risk assessment and health implication

2013

Our study reports on the total mercury (HgT) concentrations measured in the muscles and livers of several benthic, demersal and pelagic fish species caught inside and outside of Augusta Bay (southern Italy), a semi-enclosed marine area, highly contaminated by the uncontrolled (since the 1950s to 1978s) discharge of the largest European petrochemical plant. Mercury levels in fish tissues are discussed with regard to specific habitat, size and/or age of the specimens and HgT distribution in the bottom sediments. Results suggest a still active Hg release mechanism from the polluted sediments to the marine environment. Also, the high HgT concentrations measured in fishes caught in the external …

Long-term response of marine benthic fauna to thin-layer capping with powdered activated carbon in the Grenland fjords, Norway

2021

The Grenland fjords in Norway have a long history of contamination by large emissions of dioxins and mercury. As a possible sediment remediation method in situ, thin-layer capping with powdered activated carbon (AC) mixed with clay was applied at two test sites at 30 m and 95 m depth in the Grenland fjords. This study presents long-term effects of the AC treatment on the benthic community structure, i.e. nine years after capping. Capping with AC significantly reduced the number of species, their abundance and biomass at the two test sites, compared to uncapped reference sites. At the more shallow site, the dominant brittle star species Amphiura filiformis disappeared shortly after capping a…

Bottom-Up Control of Macrobenthic Communities in a Guanotrophic Coastal System

2015

Soft bottom macrobenthic communities were studied seasonally in three coastal ponds (Marinello ponds, Italy) at increasing distances from a gull (Larus michahellis) colony to in- vestigate the effect of seabird-induced eutrophication (i.e. guanotrophication) on macro- benthic fauna.We hypothesized that enhanced nutrient concentration and organic load caused by guano input significantly alter the trophic and sedimentological condition of ponds, affecting benthic fauna through a bottom-up control. The influence of a set of envi- ronmental features on macrobenthic assemblages was also tested. Overall, the lowest macrobenthic abundances and functional group diversity were found in deeper sites,…

Toxicity Testing of Silver Nanoparticles in Artificial and Natural Sediments Using the Benthic Organism Lumbriculus variegatus

2016

The increased use of silver nanoparticles (AgNP) in industrial and consumer products worldwide has resulted in their release to aquatic environments. Previous studies have mainly focused on the effects of AgNP on pelagic species, whereas few studies have assessed the risks to benthic invertebrates despite the fact that the sediments act as a large potential sink for NPs. In this study, the toxicity of sediment-associated AgNP was evaluated using the standard sediment toxicity test for chemicals provided by the Organization of Economic Cooperation and Development. The freshwater benthic oligochaete worm Lumbriculus variegatus was exposed to sediment-associated AgNP in artificial and natural …

Caddis larvae (Trichoptera, Hydropsychidae) indicate delaying recovery of a watercourse polluted by pulp and paper industry

2012

Abstract We studied ecotoxicological responses of aquatic insects to evaluate the recovery of a watercourse with a history of over 100 years as a recipient of pulp and paper mill effluents. The recovery of the water quality began in 1985 due to the improved technology, but ecotoxicological effects on biota have still been evident two decades later, as indicated by morphological abnormalities in tracheal gills of caddis larvae. We hypothesized that these abnormalities are related to organic contaminants, such as resin acids, alkylated PAHs and chlorinated organic compounds, released historically from the mills, and more recently via resuspension from the sediment. Samples were collected betw…

Relazione tra le densità di Dendropoma petraeum e la microtopografia del reef a vermeti”

2011

The Chironomidae (Diptera) in Two Polyhumic Reservoirs in Western Finland

1980

ABSTRACT Composition and distribution of chironomid and other benthic fauna was studied at two adjacent 15 years old polyhumic reservoirs in western Finland by taking benthic and emergence samples. The littoral (0.5 m) coarse debris habitats, previously coniferous forest, had considerably less chironomid larvae (6–7 types, maximally 800 individuals or 0.1 g, AFDW/m2) than the mossgrown habitats, previously peatland (9–10 types, maximally 4000 individuals or 3·4 g/m2). The Chironomus larvae which were dominant at the moss sites were almost lacking at the coarse debris sites. Zalutschia zalutschicola Lipina and Tonytarsus larvae were found only at the deepest areas at 6 m. Altogether 17 speci…

Effects of temperature and sediment properties on benthic CO2production in an oligotrophic boreal lake

2010

Summary 1. Temperature and many other physical and chemical factors affecting CO2 production in lake sediments vary significantly both seasonally and spatially. The effects of temperature and sediment properties on benthic CO2 production were studied in in situ and in vitro experiments in the boreal oligotrophic Lake Paajarvi, southern Finland. 2. In in situ experiments, temperature of the water overlying the shallow littoral sediment varied seasonally between 0.5 and 15.7 °C, but in deep water (≥20 m) the range was only 1.1–6.6 °C. The same exponential model (r2 = 0.70) described the temperature dependence at 1.2, 10 and 20 m depths. At 2.5 and 5 m depths, however, the slopes of the two re…

Application of the new multimetric MMI_PL index for biological water quality assessment in reference and human-impacted streams (Poland, the Slovak R…

2014

Abstract A new multimetric MMI_PL index, which is based on the macroinvertebrate composition and combines six single key metrics, has already been implemented in Poland according to the requirements of the EU Water Framework Directive. The objectives of our survey were to assess the biological water quality using the new multimetric MMI_PL index in both reference and human-impacted streams, to analyze whether the values of the new multimetric index properly reflect the ecological status of the water in upland and mountain streams as well as to determine which environmental factors influence the distribution of benthic macroinvertebrates and the values of the metrics. The study was carried o…

Use of the preliminary Jedlice Reservoir for water protection in the Turawa Reservoir on the Mała Panew River

2009

Abstract Physico-chemical variables of water quality and benthic community structure were assessed in order to evaluate the need for reinstating the use of the preliminary Jedlice Reservoir. The waters of the Mała Panew River carry a significant load of nutrient compounds, particularly nitrates and phosphates. Deteriorating water quality results in permanent algal blooms and changes in the macrofauna structure. It was confirmed that the use of a preliminary reservoir could contribute to the protection of the Turawa Dam Reservoir against pollutants transported by the waters of the Mała Panew River.