Aquatic Biotopes Research Articles

Morphology and ultrastructure of the gills in two Urodela species: Salamandrina terdigitata and Triturus carnifex

Gill morphology and ultrastructure are described for Triturus carnifex and Salamandrina terdigitata with emphasis on differences occurring between two species that inhabit different aquatic biotopes. The morphology and ultrastructure have been studied using light microscopy and both scanning and transmission electron microscopy. The general organization of the gills is similar in the two species and shows the characteristics of Urodela larvae in which the gills consist of three tufts of filaments supported by gill arches III, IV and V. However, some differences are noticeable in the length of the main filament and in the number of secondary lamellae: in T. carnifex, a pond‐dwelling salamander, the main filaments are long and rich in secondary lamellae; in the stream‐type larva of S. terdigitata, the main filaments are shorter and show a lower number of secondary lamellae, located in its proximal portion. The cellular composition of the gill filament and of respiratory lamellae is different in S. terdigitata: in the gill filament basal cells, pavement cells, ciliated cells, club‐shaped cells, mitochondria rich cells (MRCs) and Leydig cells have been recognized, while in the secondary lamellae the last cellular type does not appear. On the contrary, in T. carnifex we observe the same cellular composition in both filament and secondary lamellae.

Detection of Virulence Genes in Vibrio cholerae Isolated from Aquatic Environment in Kerala, Southern India

Vibrio cholerae is the etiologic agent of cholera. It is an autochthonous inhabitant of all aquatic environments. The virulence of V. cholerae is maintained by the CTX genetic element and tcpA gene. In the present investigation, environmental strains of V. cholerae isolated from different aquatic biotopes in Kerala were identified and serotyped. The antibiotic resistance pattern and presence of virulence and regulatory genes were examined. We found the presence of toxigenic non-O1/non-O139 strains harboring the CTX genetic element, heat-stable enterotoxin, rtxA gene, El Tor hemolysin, and Vibrio pathogenicity island (VPI). The strains also produced the cholera toxin (CT) as determined by monosialoganglioside enzyme-linked immunosorbent assay. A few strains belonging to the O1 serogroup but lacking the CTX genetic element were also observed. The majority of the environmental strains belonged to non-O1/non-O139 serogroup with many possessing toxR, ompU, heat-stable enterotoxin, and rtxA gene. The toxigenic non-O1/non-O139 strains exhibited resistance to trimethoprim, ampicillin, and polymixin B and intermediate resistance to co-trimoxazole. However, all other environmental strains were found resistant to ampicillin and polymixin B. Our findings demonstrate that the virulence genes are dispersed among the environmental strains of V. cholerae and a complex aquatic environment can give rise to pathogenic V. cholerae.

Industrial ecology: engineered representation of sustainability

Industrial ecology is a relatively new field of research and academic study and is well established in North America and in several Asian countries. However, it has not yet received the attention it deserves in some other important parts of the industrialized world, including Germany. This paper may contribute to a better appreciation of industrial ecology as a tool in the process of sustainable development of economies, social systems, and of aquatic and terrestrial biotopes under the pressure of rapidly changing conditions triggered by global warming and urban growth. For this reason, methods are needed to quantify the successful application of industrial ecology measures. The “Integrated Sustainability Triangle” is introduced as a promising new possibility of quantification and monitoring. It enables justification of the contributions industrial ecology can make to sustainable development. The aggregation of individual economic contributions is assumed to create an overall impetus to the entire industrial sector including the sector of environmental engineering. Thus, the potential of industrial ecology is discussed from the macro-economic and the engineering perspective using the concept of sustainable development as a guiding principle. But the authors come to the conclusion that finding solutions to the pressing problems of our time requires more than collaboration of economy and engineering. It requires joint efforts of the whole spectrum of scientific disciplines in close collaboration with industrial and political stakeholders.

The effect of biotope-specific sampling for aquatic macroinvertebrates on reference site classification and the identification of environmental predictors in Mpumalanga, South Africa

The classification of reference sites based on macroinvertebrate assemblages sampled in different aquatic biotopes in Mpumalanga, South Africa, was examined. Environmental variables that best predicted group membership for each of four classifications (stones, vegetation, sand and these three biotopes combined) were identified. Variables at several scales, including catchment, site and habitat, contributed to observed spatial patterns in macroinvertebrate assemblages. Altitude and longitude were important for combined, stones, and vegetation classifications, reflecting the importance of longitudinal zonation and geographic location, respectively. The characteristics of the substratum, including type (bedrock rapid versus cobble riffle), depth, and quality (deposition of silt on stones), were important at habitat scale. Canopy cover was identified as an important predictor in the stones classification. Geological type, which affects overall water chemistry, was important in the stones and combined classification, and temperature was important in the combined classification. Whilst this study is based on correlative data only, it demonstrates that the structure of macroinvertebrate assemblages is a function of both large-scale variables measured at catchment scale and smaller-scale variables measured at site and habitat scale. The study highlights the importance of measuring environmental variables within bioassessment programmes, especially when classifying and assessing reference sites.

Measuring resistant forms of two pathogenic protozoa (Giardia spp and Cryptosporidium spp) in two aquatic biotopes in Yaoundé (Cameroon)

Organisms of the genera Cryptosporidium and Giardia are enteric parasites that are responsible for cryptosporidiosis and giardiasis respectively. They are characterised by profuse diarrhoea, abdominal pain and cramping. The symptoms can be fatal for immunodepressed subjects and children because these are opportunistic pathogens. These pathogenic infections are rampant in developing countries due to the unhygienic and improper disposal of wastewater and the use of surface water as the major sources of potable water. Little information is available about the resistant forms of these microorganisms in the hydrosystems of Cameroon in particular and other sub-Saharan ecosystems in general. The aim of this research was to isolate, identify, and measure these forms of these emerging protozoa in the waste and surface waters of Yaoundé, Cameroon. Giardia spp cysts were identified by Lugol iodine staining, and the Cryptosporidium spp oocysts by the Ziehl-Neelsen technique. The cysts were oval in structure and varied in length from 7 um to 12.0 um. Axostyles were visible along the median line and nuclei were present. The oocysts were round in structure and varied in diameter from 4 um to 6 um. A double cell wall was seen in the apicomplexa. The highest concentrations of Giardia spp cysts were 560 cysts/L in the surface water and 650 cysts/L in the residual effluent, while the corresponding figures for Cryptosporidium spp were 1,110 oocysts/L in the stream and 1,500 oocysts/L in the effluent. The cyst and oocyst counts were higher in the direct effluent because they are released directly into the wastewater by feces, while they are diluted in the surface water, reducing their abundance. Turbidity has a significant effect (p<0.05) on the population dynamics of these microorganisms, thereby indicating the importance of suspended or colloidal particles in the dissemination of these pathogens in aquatic media. The suspended particles in the wastewater adsorb the oocysts and cysts, probably because of the interactions between the electric charges carried by suspended particles and those present at the surface of the parasites. The positive correlation observed between these parasites and ammonia may account for some of the die-off of these resistant forms, because ammonium ions in water are known to inactivate trophozoites and sporozoites present in cysts and oocysts. This may be due to the permeability of the protozoan membrane to the ammonium ion and other alkaline earth metals present in aqueous form in the biotope. These parasite forms in these media represent a considerable health risk to the inhabitants of the study zone who depend on this surface water for drinking. The small size of these parasitic forms, the nonfunctional water purification stations and ineffective water treatment systems expose the community to outbreaks of giardiasis and cryptosporidiosis.

Factors affecting the removal of organic micropollutants from wastewater in conventional treatment plants (CTP) and membrane bioreactors (MBR)

As a consequence of insufficient removal during treatment of wastewater released from industry and households, different classes of organic micropollutants are nowadays detected in surface and drinking water. Among these micropollutants, bioactive substances, e.g., endocrine disrupting compounds and pharmaceuticals, have been incriminated in negative effects on living organisms in aquatic biotope. Much research was done in the last years on the fate and removal of those compounds from wastewater. An important point it is to understand the role of applied treatment conditions (sludge retention time (SRT), biomass concentration, temperature, pH value, dominant class of micropollutants, etc.) for the efficiency of conventional treatment plants (CTP) and membrane bioreactors (MBR) concerning the removal of micropollutants such as pharmaceuticals, steroid- and xeno-estrogens. Nevertheless, the removal rates differ even from one compound to the other and are related to the physico-chemical characteristics of the xenobiotics.

Impact Of River Flow Regulation On The Planktonic Population In Ganga River At Rishikesh (Uttaranchal)

Biological monitoring is an essential element to assess the environmental health of aquatic biotopes. Any stress imposed in aquatic ecosystem manifests its impact on the inhabitant communities and result in restructuring the present biotic components. The present study is an effort to assess the impact of damming of river water on the physico-chemical characteristics and their relations to planktonic population of Ganga river. Results indicated remarkable changes in some physico-chemical factors in upstream and downstream of Ganga river at Pashulok barrage. Rich planktonic concentration were observed as 1273.67 ± 598.124 and 1184.25 ± 588.724 units/l in the upstream and downstream section respectively. Phytoplankton always dominated (88.4 to 91.7%) over zooplankton and mainly constituted by Bacillariophyceae (65.07-78.95%) followed by Chlorophyceae (25.34-17.14%) in Ganga river.

A Strategic Interpretation of Beetle (Coleoptera) Assemblages, Biotopes, Habitats and Distribution, and the Conservation Implications

The identification of beetle, and other invertebrate, biotopes based on the recording of species assemblages has become a regular occurrence as a result of increased survey work, with the approach expanded into classifications of grid square pooled species lists at the national scale. A reassessment of beetle biotopes and distribution has been attempted by interpreting the classifications in terms of the major environmental factors of productivity and disturbance, identified as being important drivers in work on habitat templates and strategic triangles. For grassland ground beetle biotopes, productivity was generally related to soil quality whilst disturbance was associated with land management or cover. Productivity of exposed riverine sediment ground beetle biotopes was dependent on deposited organic matter and disturbance on the effects of water flow on site structure. With both ground beetle biotopes, the distribution of assemblages was also affected by substrate water, another abiotic driver. Productivity in aquatic beetle biotopes was a function of base-status, generally reflected by pH, whilst disturbance was mainly due to water flow and wave action. However, disturbance in ditches was also the result of site vegetation management whilst another factor affecting assemblage distribution was water permanence, with temporary water having specific assemblages. For large-scale British, grid-based, classifications productivity and disturbance were interpreted from satellite-derived land cover data. At the national scale, the other important factor influencing distribution was temperature. There is a requirement for better quantification of a number of the factors influencing biotope and assemblage definition. Species strategies employed to cope with the various environmental variables were reflected in traits in such factors as morphology and life-cycles. The effects of environmental perturbations including climate change, pollution and land use are discussed in relation to the environmental variables and to the various species strategies. Biotope classifications, using standardised and reproducible survey methods, allied to a better understanding of the underlying environmental pressures, could produce a unified approach for the conservation of beetle and other invertebrate species.

Distribution of Anodonta (Sinanodonta) woodiana (Rea, 1834) in inland waters of Serbia

Aquatic biotopes are, due to their unique features, among the most disposed ecosystems to bioinvasions. Serbian waters are not an exception, with a increasing colonization by allochthonous organisms observed there during the last few decades. Nonindigenous aquatic species were found among plants, vertebrates and invertebrates. One of the most invasive aquatic macroinvertebrate species found in the region is the Chinese pond mussel Anodonta (Sinanodonta) woodiana (Rea, 1834). The species is dispersed along lowland rivers, associated wetlands and manmade canals. Heavily modified and artificial aquatic habitats, with high silting rates, were found to be especially suitable for population by A. woodiana. A mass occurrence of Chinese mussel was observed among these habitats, particularly where bottom substrata were characterised by the domination of silt-clay.

Differentiation of tetrapod communities and some aspects of biotic events in the early triassic of Eastern Europe

The patterns of spatial differentiation of the Early Mesozoic terrestrial biota in Eastern Europe and Australia-Tasmania demonstrate that the tetrapod faunal recovery following the Permian extinction was characterized by both global and regional heterogeneity. Local distinctions observed in the development of Early Triassic tetrapod assemblages of European Russia allow the recognition of the following realms: (1) the central and northern regions of the East European Platform (Moscow-Mezen Syncline) and the Timan-North Ural Region; (2) the southern Fore-Urals, including the Obshchii Syrt Plateau; and (3) the southern regions of the East European Platform (the slope of the Voronezh Anticline). Climatic conditions at the initial stage of the development of local communities were characterized by an increase in aridity and seasonal contrasts of climate. Therefore, terrestrial assemblages mostly concentrated in the aquatic and coastal biotopes. Accordingly, vertebrate assemblages of the region were dominated everywhere by aquatic amphibians and semiaquatic reptiles, while the accompanying palynomorph assemblages show the predominance of hygrophilous vegetation indicative of swampy mangrove setting. With respect to amphibians, a peak of local biogeographic differentiation falls on the onset of the Early Triassic and, in the case of reptiles, on the end of this time span. This change conforms to the increasing role of reptiles in the overall taxonomic diversity with time. Among the three main biogeographic units of the region, the Southern Fore-Ural Realm is distinguished by the maintenance of distinct faunal links with Gondwanan regions. The Southern Realm shows a connection with the Germanic Basin and more western Euramerican areas, which is documented for the Late Olenekian and occurred under influence of coastal marine conditions.

Distribution of Non-Indigenous Tubificid Worm Branchiura Sowerbyi (Beddard, 1892) in Serbia

ABSTRACTRecently, dispersion of invasive species became an important theme, since the man-aided outspread of the organisms was recognized as one of the major threats to the biodiversity. Aquatic biotopes are, due to its unique features, among the most disposed ecosystems to this kind of disturbance. Non-indigenous species of different origin were found among plants, vertebrates and invertebrates. Aquatic worm Branchiura sowerbyi (Beddard 1892) is obvious example of human induced dispersal of invertebrates. The aim of the study was to contribute to the cognition of the current distribution of this invasive species and to point up, once again, the risk of devastation of aquatic ecosystems caused by distribution of alien species. B. sowerbyi was for the first time observed in Serbia in 1972 in fish pond in Vojvodina. Since that time the worm spread its areal and now it could be found in a lot of ponds, channels, reservoirs and lowland rivers in Serbia. According to our results B. sowerbyi has been well adapted in artificial and modified water bodies in Serbia.

The Charetum contrariae association, new to Hungary

The Charetum contrariae, stoneworth plant community, was found during the research of aquatic biotopes in the catchment area of the Ipeľ river in the summer of 2000. It has not been detected in Hungary. Up to now, the community is known from Slovakia and Poland at the territory of Central Europe.

A Preliminary Survey of the Birds from Velikent (Bronze Age, Daghestan, Russia)

This paper presents a preliminary overview of the bird remains from the early/middle Bronze Age site of Velikent, a series of mounds situated on the Caspian coastal plain of the Russian republic of Daghestan. A total of 25 taxa, including 21 species, have been identified thus far. They represent species from both aquatic and terrestrial biotopes, although one species, the Great bustard, Otis tarda, constitutes the dominant element of all subsamples . Whether this was actually so or not and whether most of the secondary patterns reported below are trustworthy is an open question partly due to the small samples thus far available for study and partly to a manual retrieval of remains that will need to be improved in the future if patterns are to be coupled with those available for comparison from other faunal sets, domestic mammals in particular.

Seasonal dynamics of rotifers in relation to physical and chemical conditions of the river Yamuna (Delhi), India

We examined the seasonal succession of the rotifer assemblages in the backwaters of the Delhi segment of the river Yamuna in relation to 18 physical–chemical variables across one year. These shallow, weedy, and perennial aquatic biotopes support a diverse and abundant zooplankton. A total of 89 rotifer species belonging to 34 genera and 18 families were recorded. Their seasonal dynamics were characterized by (i) maxima and minima in total densities during spring–early summer and winter, respectively; (ii) individual species reaching maximum and minimum densities during different seasons; and (iii) an absence of seasonal variation in species diversity. The relative importance of various physical and chemical factors in determining rotifer community structure and seasonal succession is evaluated and Pearson-product moment correlations between physical–chemical variates and rotifer densities are analyzed and discussed.

Ecomorphological Characteristics of the Marsh Frog Rana ridibunda from the Galich'ya Gora Nature Reserve

The marsh frog is a widespread and flexible speciesthat mainly occupies various aquatic biotopes. In theLipetsk oblast, these frogs avoid only closed forestwater bodies and springs, and their habitats in the Cen-tral Russian Upland and the Oka–Don Lowland obvi-ously differ from each other. According to Klimov et al. (1999), the number of these amphibians in the Oka–Don Lowland is greater. The comparison of morpho-logical variation in frogs from these regions shows thatthe pressure of natural selection is greater in the CentralRussian Upland (Vykhodtseva, 1992; Vykhodtseva andKlimov, 1993; Kovylina and Vykhodtseva, 1993; Kli-mov et al. , 1999), and this pressure determines the rela-tionship between the demographic and morphologicalcharacteristics of the amphibian populations.This study was performed at the Galich’ya GoraNature Reserve (Zadonskii raion, Lipetsk oblast) withthe purpose of analyzing the changes in the morpholog-ical parameters of frogs depending on the biotopiccharacteristics of the environment.The material was collected on the bank of the DonRiver within the reserve on August 14–22, 1996. Thecorresponding segment of the river is approximately 3km long. Mount Morozova is located on its left bank.Its northern part is a forested slope descending to thefloodplain. Southward, the floodplain sharply narrows,and the slope becomes steeper and descends almost tothe edge of water. Mount Galich’ya is on the right bank.The floodplain is only in its southernmost part; in otherplaces, the sloping primary bank adjoins the edge ofwater.The banks of the Don River and their plant cover inthese areas are fairly variable. For this reason, the studyarea was arbitrarily divided into several sites with moreor less similar conditions: (1) a flat sandy bank withrare clumps of willow, (2) a steep sandy bank over-grown with willow, (3) a steep sandy bank partiallycovered with willow and riparian grasses, (4) a steppebank partially covered with willow and ripariangrasses, (5) a mainly stony bank covered with a forest,and (6) a steep bank overgrown with thick ripariangrasses and rare clumps of willow (Fig. 1). Sites 1–3were on Mount Morozova, and sites 4–6, on MountGalich’ya.At each site, no less than 30 frogs of different sexand age groups (i.e., female, male, adultus, and sub-adultus) were collected. On the whole, there were 169frogs from five sites (the frogs rarely appeared at site 1).The phenetic description of Rana ridibunda frogswas made according to the studies by Borkin andTikhenko (1976, 1979), Zhukov and Kubantsev (1976),and Peskov (1976). Eight characters were analyzed, sixon the dorsal and two on the ventral side:(1) Dl , the central (dorsomedial) strip (1, absent; 2,from the snout to the anus; 3, from the snout to the pec-toral girdle; 4, from the snout to the pelvic girdle; 5,from the eyes to the anus; 6, from the eyes to the pelvicgirdle; 7, from the nostrils to the anus; and 8, a traceconsisting of several spots).(2) s , the discontinuity of the central strip (1, in thepectoral girdle area; 2, in the hind limb area; and 3, inthe forelimb area and in the middle of the back).(3) z , the sinuousness of the central strip (1, a bendin the front limb area; 2, a bend in the area of the tym-panic membrane and the middle of the back; 3, a bendin the tympanic membrane area; 4, displacement to oneside in the hind limb area; 5, a bend in the eye area; and6, a bend in the hind limb area).

Significance of side-tributaries and floodplains for Danubian fish populations.

Changes of aquatic biotopes and the natural dynamics of the Danube by human activity were the main cause of fish decline since the 19 th century. Several fish species have recently displayed a drastic reduction in their distribution, and some of them are close to extinction. The restoration fo floodplain functions and biotope diversity is essential for the successful management of fish populations. The present paper describes the most important long-term changes of the Middle Danubian hydrosystem due to river regulations and summarizes the main habitat requirements of fish.

SSU rRNA-based phylogenetic position of the genera Amoeba and Chaos (Lobosea, Gymnamoebia): the origin of gymnamoebae revisited.

Naked lobose amoebae (gymnamoebae) are among the most abundant group of protists present in all aquatic and terrestrial biotopes. Yet, because of lack of informative morphological characters, the origin and evolutionary history of gymnamoebae are poorly known. The first molecular studies revealed multiple origins for the amoeboid lineages and an extraordinary diversity of amoebae species. Molecular data, however, exist only for a few species of the numerous taxa belonging to this group. Here, we present the small-subunit (SSU) rDNA sequences of four species of typical large gymnamoebae: Amoeba proteus, Amoeba leningradensis, Chaos nobile, and Chaos carolinense. Sequence analysis suggests that the four species are closely related to the species of genera Saccamoeba, Leptomyxa, Rhizamoeba, Paraflabellula, Hartmannella, and Echinamoeba. All of them form a relatively well-supported clade, which corresponds to the subclass Gymnamoebia, in agreement with morphology-based taxonomy. The other gymnamoebae cluster in small groups or branch separately. Their relationships change depending on the type of analysis and the model of nucleotide substitution. All gymnamoebae branch together in Neighbor-Joining analysis with corrections for among-site rate heterogeneity and proportion of invariable sites. This clade, however, is not statistically supported by SSU rRNA gene sequences and further analysis of protein sequence data will be necessary to test the monophyly of gymnamoebae.

Colonisation par la faune des dépressions créées par la verse des arbres suite à l'ouragan Lothar – premiers constats dans quelques forêts vaudoises | The role of depressions resulting from uprooted trees as new biotopes – preliminary observations in forests after hurricane Lothar

On 26th December 1999, hurricane Lothar blew over Europe causing widespread damages, particularly on forested areas of Western Switzerland. One consequence of uprooted trees were depressions in the ground where rain water could collect and remain, depending on the soil characteristics. Colonisation of these aquatic depressions by plants and animals was surveyed in 2000. Our study showed that these new depressions were only colonized secondarily, organisms (insects and amphibians)preferring aquatic biotopes already present in the surrounding forest such as ditches, marshes or ponds. First colonization started around mid-May, but only within the depressions which were deep and filled with permanent water. The present study describes the colonization process of these depressions and discusses their contribution to forest biodiversity.

Polybrominated diphenyl ethers: occurrence, dietary exposure, and toxicology.

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in plastics (concentration, 5--30%) and in textile coatings. Commercial products consist predominantly of penta-, octa-, and decabromodiphenyl ether mixtures, and global PBDE production is about 40,000 tons per year. PBDEs are bioaccumulated and biomagnified in the environment, and comparatively high levels are often found in aquatic biotopes from different parts of the world. During the mid-1970--1980s there was a substantial increase in the PBDE levels with time in both sediments and aquatic biota, whereas the latest Swedish data (pike and guillemot egg) may indicate that levels are at steady state or are decreasing. However, exponentially increasing PBDE levels have been observed in mother's milk during 1972--1997. Based on levels in food from 1999, the dietary intake of PBDE in Sweden has been estimated to be 0.05 microg per day. Characteristic end points of animal toxicity are hepatotoxicity, embryotoxicity, and thyroid effects as well as maternal toxicity during gestation. Recently, behavioral effects have been observed in mice on administration of PBDEs during a critical period after birth. Based on the critical effects reported in available studies, we consider the lowest-observed-adverse-effect level (LOAEL) value of the PBDE group to be 1 mg/kg/day (primarily based on effects of pentaBDEs). In conclusion, with the scientific knowledge of today and based on Nordic intake data, the possible consumer health risk from PBDEs appears limited, as a factor of over 10(6) separates the estimated present mean dietary intake from the suggested LOAEL value. However, the presence of many and important data gaps, including those in carcinogenicity, reproduction, and developmental toxicity, as well as additional routes of exposure, make this conclusion only preliminary. Moreover, the time trend of PBDEs in human breast milk is alarming for the future.

Concentrations of 17 elements in the zebra mussel (Dreissena polymorpha), in different tissues of perch (Perca fluviatilis), and in perch intestinal parasites (Acanthocephalus lucii) from the subalpine lake Mondsee, Austria

AbstractConcentrations of the elements Al, Ag, Ba, Ca, Cd, Co, Cr, Cu, Fe, Ga, Mg, Mn, Ni, Pb, Sr, Tl, and Zn were analyzed by inductively coupled plasma mass spectrometry in the acanthocephalan Acanthocephalus lucii (Müller); in its host, Perca fluviatilis (L.), and in the soft tissue of the zebra mussel, Dreissena polymorpha (Pallas). All animals were collected from the same sampling site in a subalpine lake, Mondsee, in Austria. Most of the elements were found at significantly higher concentrations in the acanthocephalan than in different tissues (muscle, liver, and intestinal wall) of its perch host. Only Co was concentrated in the liver of perch to a level that was significantly higher than that found in the parasite. Most of the analyzed elements were also present at significantly higher concentrations in A. lucii than in D. polymorpha. Barium and Cr were the only elements recorded at higher concentrations in the mussel compared with the acanthocephalan. Thus, when comparing the accumulation of elements, the acanthocephalans appear to be even more suitable than the zebra mussels in terms of their use in the detection of metal contamination within aquatic biotopes. Spearman correlation analysis revealed that the concentrations of several elements within the parasites decreased with an increasing infrapopulation. Furthermore, the levels of some elements in the perch liver were negatively correlated with the weight of A. lucii in the intestine. Thus, it emerged that not only is there competition for elements between acanthocephalans inside the gut but there is also competition for these elements between the host and the parasites. The elevated element concentrations demonstrated here in the parasitic worm A. lucii provide support for further investigations of these common helminths and of their accumulation properties.