Macrozoobenthos Samples Research Articles

Reference conditions of German stream types analysed and revised with macroinvertebrate fauna

This study investigates reference conditions of German stream types using the top-down stream typology developed by Pottgiesser & Sommerhäuser (2004) and 264 macrozoobenthos samples selected as representing reference status. With the aid of discriminant and correlation analyses, the use of typological parameters is investigated as regards their relevancy and the study aims to show whether the metrics used in the newly developed type-specific indices ( Böhmer et al. 2004b) reflect the reference conditions. The data cover 15 of the 24 German stream types. The use of stream size, of ecoregions as an indirect parameter for geographical altitude, and of the bottom substrate for the lowland stream types as typological factors can be confirmed, as can six stream types as separate and independent. As bottom substrate is an essential factor for the lowland stream types, their independency is at least probable. For the stream types of the lower mountain regions, a separation of siliceous and calcareous types seems not to be crucial for the bioassessment on metric level, while a new approach for and a possible splitting of the small streams in floodplains is recommended.

The environmental effects of the installation and functioning of the submarine SwePol Link HVDC transmission line: a case study of the Polish Marine Area of the Baltic Sea

This paper describes the two-phase study of the environmental impact of the SwePol Link submarine electrical energy transfer system between Sweden and Poland. During the first phase (1997–1998), the potential effects of proposed technical solutions for the transmission line and different routes across the Baltic Sea were analysed. During the second phase (1999–2000), studies on environmental and background conditions before cable installation (1999) and studies on the environmental effects after cable system installation (2000) were undertaken. During this phase, underwater TV and video inspection of the bottom, observations of the bottom habitats by scuba-divers, sampling and laboratory analysis of macrozoobenthos and measurements of the earth's magnetic field were conducted. Underwater observations along the cable route indicated that one year after the cable had been laid no mechanical disturbances on the dynamic sandy bottom were visible. Studies of the bottom macrofauna indicated that there had been no significant changes in zoobenthos species composition, abundance or biomass which could have been clearly related to cable installation. Changes in the components of the magnetic field, although significant in the vicinity of the cable itself, did not exceed natural variability at a distance of 20 m.

Impact of iceberg scouring on macrobenthic communities in the high-Antarctic Weddell Sea

UW-video guided multibox corer sampling in- and outside iceberg scours provided quantitative macrozoobenthos samples for analyses of effects of grounding icebergs on infaunal benthic communities. These studies were performed on the southeastern Weddell Sea shelf off Kapp Norvegia and Austasen. Based on the UW-video sequences, stations were grouped a priori into two different "disturbance categories" and into undisturbed areas.

Determination of trace elements in macrozoobenthos samples by total reflection X-ray fluorescence analysis

The paper describes the analysis of a set of metals in macrozoobenthos samples from a river in Western Austria by using total reflection X-ray fluorescence analysis (TXRF). Metal concentrations in aquatic insect larvae from an industrially contaminated site are significantly higher than in larvae from a reference site. Furthermore, species-specific differences in metal accumulation were found. TXRF allows multi-element analysis of very low metal concentrations in very small sample masses (e.g. single aquatic insect larvae with a dry weight of only a few milligrams). Due to its multi-element capability and high sensitivity total reflection X-ray fluorescence analysis is a valuable tool for biomonitoring studies of metal contamination in aquatic ecosystems.

Stream acidification in South Germany – chemical and biological assessment methods and trends*

Chemical measurements are designed to classify acid sensitive streams in Baden-Wurttemberg (South West Germany) as a basis on which a biological indication method for stream acidity is worked out. Sampling of macrozoobenthos is carried out as a basis for the biological classification of the degree of acidity in acid sensitive silicate streams. Interlinking of the chemical and biological data is made with, among others, statistical methods aiming to describe the pH values and other parameters relevant to acidification which effect the presence of the organisms. The sensitivity levels of the benthic macroinvertebrates are related to the pH values and the corresponding indicator values for the bioindication are assigned to the current acidification level of the calcium-poor streams. Relevant data, information, and procedures from literature were hereby taken into account. Computer-aided assessment of the acidity status of the slightly-buffered streams based on the macrobenthic cenosis following the principle of maximum biological sensitivity of the individual taxa has been carried out. This has been done by successive examination of the values of all observed indicator species, beginning with the most acid sensitive ones. Cartographic presentation of the biological results – obtained between 1992 and 1998 – reveals a slight improvement of the degree of acidity in streams of the Black Forest. This can also be observed in the chemical data. Most sampling sites show an increasing trend in pH-values as well as in buffer capacity. On the other hand most of the streams in poorly buffered areas show a declining trend in their aluminium concentrations and their content of sulphate-ions, which is a consequence of the decreasing sulphur-dioxide concentrations in the air during the last 15 years.

Semi-quantitative study of macrobenthic fauna in the region of the South Shetland Islands and the Antarctic Peninsula

During the BENTART 95 Expedition, 24 Agassiz trawls for macrozoobenthos sampling were carried out at depths of 40–850 m, from north of Livingston Island to the Antarctic Peninsula. The samples were analysed using a semi-quantitative method, and with the resulting numerical data, transformed into a six-point scale, we constructed a Bray-Curtis similarity matrix. A total of 74,624 specimens, belonging to 38 taxonomic groups, were collected. The most abundant group was Polychaeta Sedentaria, with 36% of the total, whereas the highest relative masses were from Ascidiacea (23%), Echinoidea Regularia (18%) and Ophiuroidea (16%). The maximum number of specimens recorded was 15,600 ind./50 l. Cluster analysis separated stations located in Foster Bay (Deception Island), characterised by low taxonomic richness and high relative mass (average: 26.7 kg). A zonation of ascidians, regular sea urchins and ophiuroids was observed at Deception Island, clearly related to depth and substratum type. The remaining stations were separated into two groups. The first one comprised the shallowest stations (40–130 m), dominated by sessile active filter-feeders, belonging to Ascidiacea, Demospongia and Bryozoa, and probably related to high primary production zones. The second group comprised deeper stations and was dominated by classes exhibiting a diversity of trophic strategies: Ophiuroidea and Asteroidea, to 400 m, and Polychaeta Sedentaria at greater depths.

An evaluation of the ABC-method (abundance/biomass comparison) as applied to macrozoobenthic communities living on tidal flats in the Dutch Wadden Sea

The ABC-method proposed by Warwick (1986) for detecting pollution effects on marine zoobenthic communities, was tested on distribution patterns of numbers and biomass among species in macrozoobenthos samples taken annually for 13 yr in a uniform way at 15 tidal-flat stations in the western part of the Dutch Wadden Sea. Along the margins of the tidal-flat area studied, where exposition to either drainage or water movements is extreme, the k-dominance plots for numbers were generally situated above those for biomass. In these areas values for biomass and species richness were relatively low and a few small-sized species such asCorophium volutator andHydrobia ulvae were very numerous. In the central part of the area, where environmental conditions are less severe, values for biomass and species richness were higher. Biomass was dominated by large adults ofMya arenaria, Mytilus edulis and/orArenicola marina. However, in only a restricted part of this area were plots for numbers consistently below biomass plots. In most of the central area high numbers ofH. ulvae occasionally occurred, causing plots for numbers to be situated above those for biomass during such periods. There appears to be no reason to interprete a high abundance ofH. ulvae as a sign of pollution or any other kind of disturbance or stress. It is concluded that the ABC method cannot be applied to tidal flat communities without reference to long-term and spatial series of control samples. In areas where such smallsized and sometimes numerous species asH. ulvae occur in strongly fluctuating numbers, the method appears useless for assessing the pollution status of a benthic community.

Baltic eutrophication: A contribution to the discussion

Abstract Quantitative sampling of macrozoobenthos has been performed in the southern Baltic in the 1920s and the 1950s. Some of these stations (43) were revisited in 1982/83. The total abundance and biomass was significantly increased in 1982/83 compared to 1921. A small, non-significant, increase in biomass was found in 1982/83 compared to the 1950s. It is suggested that the main part of the biomass increase might be due to reduced stocks of predatory flatfishes in the 1920s and 1930s. The most conspicuous difference in the comparisons is the widespread distribution of the polychaete Capitella capitata in 1982/83. This is attributed to increased trawling activities in recent decades and not to organic enrichment.

Biocenotical Classification of the Lithorheophilous Communities in the Karst Running Waters According to the Macro Benthic Fauna

AbstractThis paper analyses the biocenotical structure of the macro benthic fauna in lithorheophilous communities of karst rivers. A lithorheophilous community on different types of stony substrate was biocenotically defined on the basis of population density and determination of the index of dominance for particular representatives. Accepting today's limnological and biocenotical classifications of running waters (SHADIN; ILLIES; STEFFAN; WACHS) a lithorheophilous community in this work is taken as a choriocenosis (“Teilbiozönose”) which is a composite bio‐association of rhithron eco‐biocenosis.The qualitative and quantitative analysis of macrozoobenthos samples indicates a mosaic structure of lithorheophilous choriocenosis. Six subordinated bio‐associations were determined on the basis of dominant representatives of macro benthic fauna on four types of stony substrate in lithorheophilous choriocenosis, which is biocenotically defined as Gammaretum‐community.