Papers by aleksander Drgas
Aquatic Sciences, May 6, 2021
Although detritivorous Tubificinae and chironomid larvae are important groups in functioning of b... more Although detritivorous Tubificinae and chironomid larvae are important groups in functioning of both, fresh and brackish water ecosystem, their co-occurrence patterns in sediment is weakly known. We carried out two-year-long research in the brackish Vistula Lagoon (southern Baltic Sea), where both Tubificinae (Limnodrilus hoffmeisteri and Potamothrix hammoniensis) and larvae of Chironomus balatonicus occur in high densities. Because of different source of their food, we hypothesized that the ecological interactions between those two groups of detritivores are not antagonistic, thus allowing for their co-occurrence along the depth of sediment profile with lack of competition for space. Here we show that maximum burrowing depth, occasionally reaching 25 cm was significantly affected by the total density of the each group in the entire core. Tubificinae and C. balatonicus showed the highest density at 0-10 cm depth, where they co-occurred most frequently, with significant co-occurrence in the layers of 0-2 cm and 2-5 cm. We propose a hypothetical model of interactions between apparently the same functional groups and the complementary role they play in sediment reworking. It points to their coexistence in the shared microhabitat, but using space and food resources differently. Also, the consequences of their activity and habitat structuring are opposite-Chironomus larvae mostly affect the deeper layers of the sediments, while Oligochaeta both the deeper and surface layers. Thus, their requirements and ecological roles seem not to overlap, preventing competitive exclusion and allowing for co-occurrence.
Aquatic Sciences, 2021
Although detritivorous Tubificinae and chironomid larvae are important groups in functioning of b... more Although detritivorous Tubificinae and chironomid larvae are important groups in functioning of both, fresh and brackish water ecosystem, their co-occurrence patterns in sediment is weakly known. We carried out two-year-long research in the brackish Vistula Lagoon (southern Baltic Sea), where both Tubificinae (Limnodrilus hoffmeisteriandPotamothrix hammoniensis) and larvae ofChironomus balatonicusoccur in high densities. Because of different source of their food, we hypothesized that the ecological interactions between those two groups of detritivores are not antagonistic, thus allowing for their co-occurrence along the depth of sediment profile with lack of competition for space. Here we show that maximum burrowing depth, occasionally reaching 25 cm was significantly affected by the total density of the each group in the entire core. Tubificinae andC. balatonicusshowed the highest density at 0–10 cm depth, where they co-occurred most frequently, with significant co-occurrence in th...
Frontiers in Marine Science
Frontiers in Marine Science
Hydrobiologia
The clam Rangia cuneata, originating from the Gulf of Mexico, was recorded in the Vistula Lagoon ... more The clam Rangia cuneata, originating from the Gulf of Mexico, was recorded in the Vistula Lagoon for the first time in the early 2010s, and quickly became the dominant component of the zoobenthic biomass. To assess mortality as a factor potentially controlling the growth of Rangia population, a year-long field experiment involving marked bivalves placed in sediment-filled trays deployed on the bottom was conducted in 2014 and 2015. Predatorinduced mortality of the clams was low in summer, and very high in the winter-spring period. It was inversely proportional to the size of the clams. Such changes can be partially attributed to predation from at least five fish and three duck species, which contained clams in their digestive tracts. Non-predatory mortality particularly affected large individuals, and was highest in spring, several weeks after the end of winter. We hypothesize that it could be caused by persistent low temperatures over several winter months which led to considerable weakening of the condition of clams. A long winter could also reduce their resistance to environmental stress and potential effect of epibionts, as well as increase susceptibility to predation.
Knowledge & Management of Aquatic Ecosystems, 2017
The presented system of experimental trays permits conducting field experiments at considerable d... more The presented system of experimental trays permits conducting field experiments at considerable depths, all year round, and with no application of diving techniques. The deployed set can be entirely hidden under water, which is an advantage in crowded areas. The set is composed of single units, each composed of a tray filled with a substrate, four-legged bridles, and a hanging rope with a removable marker float fixed on top by means of a carabiner clip. The float provides information on the location of deployed trays, and permits proper distribution of next trays to be deployed. After deployment from a boat, the units are connected with a rope, extended on one end by a sinking retrieval rope. The floats are removed immediately after deployment. Any number of units can be deployed to the bottom. It depends on the experimental design and the number of replicates. Retrieval of the set starts with locating the trays by means of GPS, and searching for the retrieval rope by means of a grappling hook dragged behind the boat. Based on our own experience and the literature, the possibilities of development of the described system are proposed depending on the local field conditions and research objectives.
Environ. Sci.: Processes Impacts, 2016
This paper presents the study on the occurrence and spatial distribution of polybrominated diphen... more This paper presents the study on the occurrence and spatial distribution of polybrominated diphenyl ethers (PBDEs), butyltin compounds (BTCs), bisphenol A (BPA), and alkylphenols (APs) in sediments.
Polar Biology, 2009
Intertidal meiobenthos of Hornsund-the southernmost fjord of Spitsbergen-was investigated between... more Intertidal meiobenthos of Hornsund-the southernmost fjord of Spitsbergen-was investigated between July and September 2005. Mean total meiofaunal densities ranged between 4.3 and 328 ind. 10 cm ¡2. Nematode assemblages were impoverished in terms of the number of genera when compared with those from the western Spitsbergen coast (11 vs. 25-28 genera in total, respectively). It is suggested that severe environmental conditions in the southern part of Spitsbergen overcome the adaptation skills of many nematode species and hamper the establishment of a diverse community. Comparatively high nematode numbers on a beach subject to heavy macroalgal wrack input contrast sharply with numerically poor communities in sparse-wrack beaches (up to 315 vs. 31 ind. 10 cm ¡2 , respectively). It is suggested that the wrack input to the Arctic beach may substantially inXuence the richness and composition of the intertidal meiobenthic community. Nematode assemblages were dominated by extreme colonizers: Geomonhystera disjuncta and rhabditids. Their relatively high densities in beach sediments recorded at the beginning of July indicate their ability to recover rapidly after the winter period and to eVective (re)colonization of the intertidal habitat just after the ice melt. Average concentration of rhabditids and monhysterids associated with macroalgal wrack deposited on the upper shore was as high as 52 £ 10 3 individuals per gram of the substrate. It is hypothesized that nematodes can play a substantial role in the wrack decomposition in the Arctic intertidal.
Folia Malacologica, 2013
Live specimens of the gulf wedge clam (Rangia cuneata) were for the first time found in the Polis... more Live specimens of the gulf wedge clam (Rangia cuneata) were for the first time found in the Polish part of the Vistula Lagoon in 2011. The species is native to the Gulf of Mexico and the Atlantic coast of North America. First records of its introduction in Europe were reported in 2005 from Belgium and then in 2010 from the Russian part of the Vistula Lagoon.
Bulletin of the Sea Fisheries Institute, …, 2001
The aim of this work was to estimate the influence of the Oder River on the biological production... more The aim of this work was to estimate the influence of the Oder River on the biological production of the Pomeranian Bay and to identify the role of the local community in organic matter mineralization. The first problem was examined through the comparison of local ...
Polar Biology, 2009
Intertidal meiobenthos of Hornsund-the southernmost fjord of Spitsbergen-was investigated between... more Intertidal meiobenthos of Hornsund-the southernmost fjord of Spitsbergen-was investigated between July and September 2005. Mean total meiofaunal densities ranged between 4.3 and 328 ind. 10 cm ¡2. Nematode assemblages were impoverished in terms of the number of genera when compared with those from the western Spitsbergen coast (11 vs. 25-28 genera in total, respectively). It is suggested that severe environmental conditions in the southern part of Spitsbergen overcome the adaptation skills of many nematode species and hamper the establishment of a diverse community. Comparatively high nematode numbers on a beach subject to heavy macroalgal wrack input contrast sharply with numerically poor communities in sparse-wrack beaches (up to 315 vs. 31 ind. 10 cm ¡2 , respectively). It is suggested that the wrack input to the Arctic beach may substantially inXuence the richness and composition of the intertidal meiobenthic community. Nematode assemblages were dominated by extreme colonizers: Geomonhystera disjuncta and rhabditids. Their relatively high densities in beach sediments recorded at the beginning of July indicate their ability to recover rapidly after the winter period and to eVective (re)colonization of the intertidal habitat just after the ice melt. Average concentration of rhabditids and monhysterids associated with macroalgal wrack deposited on the upper shore was as high as 52 £ 10 3 individuals per gram of the substrate. It is hypothesized that nematodes can play a substantial role in the wrack decomposition in the Arctic intertidal.
Marine Ecology Progress Series, 1999
Benthic biomass size spectra of meiofauna and macrofauna (BBSS) were examined at 4 sites in the A... more Benthic biomass size spectra of meiofauna and macrofauna (BBSS) were examined at 4 sites in the Asko area, on the Swedish coast of the northern Baltic Sea proper. The sites ranged in median sediment grain size from a coarse sand (680 pm) to mud (c63 pm). Previous empirical work and theory suggests that BBSS are bimodal where sediment granulometry permits the existence of both fauna that live interstitially and those that burrow; each biomass mode reflects constraints on organism body size for each activity. Two hypotheses based on this theory are tested here: (1) BBSS are bimodal in sediments which support both an interstitial and burrowing fauna and (2) the biomass trough between modes of the spectrum changes consistently with sediment grain size. None of the BBSS from any of the sites were bimodal; thus, the first hypothesis was rejected. Shapes of spectra varied somewhat among sites but showed no consistent difference related to sediment granulometry; thus, the second hypothesis was rejected. To further test these hypotheses, spectra were conf~ned to infauna by removing the surface sediment layer (0 to 1 cm), thereby removing epibenthic fauna. Both hypotheses were once again rejected when the spectra consisted of only infauna.
Marine Ecology, 1998
Biomass size spectra were prepared for benthic (macro-and meiobenthos) communities at 5 stations ... more Biomass size spectra were prepared for benthic (macro-and meiobenthos) communities at 5 stations located in the shallow, coastal area of the Gulf of Gdansk (Southern Baltic Sea). Stations differed in their sediment characteristics (coarse sand vs. organic matter-enriched fine sand). Spectra were based on measurements of meio-and macrobenthic animals collected with 3 types of gear: 24.4 and 75.0 mm diameter hand-held corers and 0.1 m2 V A N VEEN grab. Benthic biomass at the stations consisted mainly of nematodes and oligochaetes among the meiobenthos and of hydrobiid snails and Myrilu.7 d d i s among the macrobenthos. Regardless of habitat, size spectra peaked initially at the meiofaunal range weight class (251.19-501 .I9 ng C). The separation between meio-and macrobenthic peaks was, however, not as distinct as that found in other studies. Normalized size spectra demonstrated that most of the variability was introduced by macrobenthos: a rather clear separation between the macrofauna of coarse-and fine-grained sediments was evident as well. However, benthic biomass spectra of all the stations conformed to a common pattern and could be represented by a single. averaged spectrum. Problem The implications of individual body size of members of different communities in regard to community structure and function are receiving growing attention among researchers engaged in studies on both terrestrial (GRIFFITHS, 1986) and aquatic (BANSE, 1982) environments. Relationships between body size and parameters of individual performance (intrinsic growth rate, metabolism, fecundity, production etc.) extend to the population level and to that of community and ecosystem as well (PETERS, 1983). According to PETERS (1983) the aggregation of populations into mixed-species assemblages of similar body size is a form of community analysis U. S.
Journal of Environmental Monitoring, 2012
The concentrations of organochlorine pesticides, PCBs, and PCDD/Fs were measured in sediment samp... more The concentrations of organochlorine pesticides, PCBs, and PCDD/Fs were measured in sediment samples collected from the Gulf of Gdańsk, the Gdańsk Deep, the Vistula Lagoon and the off-shore waters in the southern Baltic Sea. The determinations were conducted in the fraction <63 μm. The highest levels of pollutants were found in sediments from the Gulf of Gdańsk and the Gdańsk Deep. In these sediments, concentrations of pp'-DDT and its metabolites (pp'-DDE and pp'-DDD) ranged from 2 to 11 μg kg(-1) dw. Concentrations of HCB were between 0.1 and 1.0 μg kg(-1) dw. Concentrations of the sum of α-, β-, γ-HCH were between 0.3 and 2.58 μg kg(-1) dw. Concentrations of marker PCBs ranged from about 2 to 11 μg kg(-1) dry weight. Total TEQ PCDD/F/dl-PCB values in the studied samples varied between 1 and 18 ng kg(-1) dw. The data were evaluated in terms of ecotoxicological criteria based on the environmental impact of the pollutant effects. Our research indicated that in the sediment from the southern Baltic Sea, the PCDD/F and PCBs occurred at concentrations which could be dangerous to marine organisms.
ABSTRACT MANUELA (Meiobenthic and Nematode Biodiversity Unravelling Ecological and Latitudinal As... more ABSTRACT MANUELA (Meiobenthic and Nematode Biodiversity Unravelling Ecological and Latitudinal Aspects) is a Responsive Mode Project undertaken within the MarBEF (http://www.marbef.org) EU Network of Excellence, funded under the Sixth Framework Programme of the European Union. One aim of the project was to carry out a “joint activity” across a number of European laboratories engaged in meiofaunal research. Following a planning workshop held in Hel, Poland in 2006, it was decided that a field experiment should be undertaken at four European beaches (Portugal, Belgium, Greece and Poland) aimed at examining whether meiofaunal assemblages respond in a unified manner to an environmental perturbation. Such responses have been assumed in studies of disturbance and pollution, but results have often been contradictory. This can be explained in terms of ecological theory as current models are not based on monotonic responses. However, the problem for ecologists has been to understand the location of a system (the starting point) in relation to the theoretical model. In this experiment, the experimental model was the potential disturbance effects of rainfall on beach sands not normally inundated by seawater, but known to harbour meiofaunal assemblages. The experiment also provided an opportunity to understand the potential impact of a predicted result of global warming, an increase in amount and intensity of rainfall, on marine systems. This talk will describe the background to the experiment, consider practical and scientific aspects of field experimentation and give preliminary results.
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Papers by aleksander Drgas