Anna Szaniawska

Behaviour, survival and glycogen utilisation in the baltic isopod Saduria entomon exposed to long‐term oxygen depletion

The benthic isopod Saduria entomon was exposed to different oxygen saturations (92, 6, and < 1%, T = 8°C). The behaviour of S. entomon under hypoxia and anoxia differs from that observed under normoxia. During the first few hours under low oxygen conditions animals became more active. After that time they lay motionless on the sediment surface. A few of them were partially buried. When oxygenation decreased, the percentage of individuals that emerged from the sediment rapidly increased. It was four and seven times higher under hypoxia and anoxia, respectively. S. entomon is able to survive long periods (41 days) under severe hypoxia, whereas the LT50 under anoxia varied between 12 and 18 days according to animal size. The glycogen content, which is the essential substrate for anaerobic metabolism of this species, decreased after 41 days under anoxia down to 48% of the normoxic level.

THE EFFECT OF HYPOXIA AND ANOXIA ON OSMOTIC AND IONIC REGULATION IN THE BRACKISH WATER ISOPOD SADURIA ENTOMON (LINNAEUS) FROM THE GULF OF GDANSK (SOUTHERN BALTIC)

Abstract The experimental material for the investigations was collected from the deep zones of the Gulf of Gdañsk. The experiments were performed at salinities of 3.0 PSU (96.87 mmol/kg), 7.3 PSU (235.73 mmol/kg), 15 practical salinity unit (PSU) (484.39 mmol/kg) and 25 PSU (807.32 mmol/kg) in conditions of hypoxia (saturation = 15% O2), anoxia (saturation <1% O2) and control conditions in aerated water (saturation = 100% O2), at a constant temperature of 10°C. Hypoxia (saturation = 15% O2) had no statistically significant effect (P > 0.05) on the osmoregulation of S. entomon in comparison with the control samples. Anoxia (saturation <1% O2) decreased the osmotic concentration of hemolymph in S.entomon. After 6 h only at salinity 3 PSU there was a statistically significant difference between the anoxic and control samples (P < 0.05). After 96 h there was a statistically significant tendency (P < 0.05) for the osmotic concentrations to decrease in anoxic conditions at all the salinities tested except 25 PSU. A tendency was observed for the Na+ concentrations in the hemolymph to decrease in anoxic conditions, which was statistically significant at salinity 7.3 PSU (P < 0.05) after 96 h but not statistically significant at the other salinities tested. The results show a low concentration of K+ in the hemolymph of S. entomon and slight fluctuations of K+ concentrations, but at environmental salinities the K+ concentration decreases under anoxic conditions but not to a statistically significant extent (P > 0.05).

A laboratory-based comparison of osmoregulatory ability at different water temperatures and salinities in the stenothermic isopod Saduria entomon (Linnaeus, 1758) and the eurythermic amphipod Corophium volutator (Pallas, 1766) from the Baltic Sea

The aim of the investigation was a comparison of osmoregulatory ability at different water temperatures and salinities by the stenothermic isopod Saduria entomon (Linnaeus, 1758) and the eurythermic amphipod Corophium volutator (Pallas, 1766) from the Baltic Sea. The experiments were performed under laboratory conditions at different water temperatures (5, 10 and 15 °C) and salinities (3, 6.6, 15 and 25 PSU for S. entomon and 3, 6.3, 15 and 25 PSU for C. volutator). The osmotic concentrations of the crustaceans’ haemolymph were determined using the melting point method. Temperature had a statistically significant effect on the osmoregulation in S. entomon, but had generally no statistical influence on the osmoregulation in C. volutator. This physiological information regarding adaptation provides a basis for predicting the distribution of these species in changing environments. The implications of the results for the comparative adaptability of the two species are considered.

Short-term study on the early succession stages of fouling communities in the coastal zone of Puck Bay (Southern Baltic Sea)

Short-term study on the early succession stages of fouling communities in the coastal zone of Puck Bay (southern Baltic Sea) The aim of this study was to distinguish the early succession stages of the fouling community in Puck Bay at depths of 3-7 m, to evaluate its biodiversity and to find the point at which the biodiversity of the assemblages achieved similarity. The depth at the study site was 8 m. The investigation lasted from 24 July to 22 September 2008 (61 days) when the colonisation and succession process of fouling communities is most intensive. During this period five sets of samples were collected. The investigations were focused on sessile organisms that established themselves on 105 PVC settlement panels (15 × 15 cm, 0.2 cm thick), 21 panels being deployed at each of five depths - 3, 4, 5, 6 and 7 m. A total of twelve sessile taxa and eight mobile (accompanying) taxa were identified over the course of the experiment. The panels became overgrown with fouling organisms in a characteristic manner - a layer of barnacles became covered with a layer of mussels. This type of community development created a double-layered structure (multi-strata growth). Assemblages reached a thickness of 2 cm as a result of the stratified fouling process. The species diversity was highest on 12 August (the first sampling day) at 7 m depth. Biodiversity differences during the study indicated that communities from all examined depths in Puck Bay became similar after a two-month colonisation period. By the end of the study Balanus improvisus and Mytilus trossulus were dominant in the communities at all depths.

Energy strategy of Corophium volutator (Pallas, 1766) (Amphipoda) population from the Gulf of Gdańsk

Abstract The goal of this paper is to determine seasonal changes in energy values and lipid levels in specimens of Corophium volutator from the Gulf of Gdansk as an energy strategy under the conditions of the inhabited environment. Materials for the study were collected in the near-shore part of the Gulf of Gdansk, at Swarzewo, between October 1991 and September 1992. Energy values were determined by means of a modified calorimetric microbomb of the Phillipson type. Lipids were determined by extraction using a mixture of chloroform, methanol and water. Females generally predominate in the population of Corophium volutator . This population is characterized by a low energy value, 12.69 ± (SD) 3.49 J mg −1 DW (18.22 ± (SD) 2.49 J mg −1 AFDW). The small mean lipid level in their bodies, 5.8 ± (SD) 4.14% DW, explains their relatively low energy value. It has been shown that, additional to such factors as food quality and availability, seasonal variation in the population has a significant influence on the nature of the changes in the energy value and lipid level in Corophium volutator .

The Signal Crayfish Pacifastacus leniusculus — Distribution and Invasion in the Southern Baltic Coastal River

ABSTRACT The signal crayfish Pacifastacus leniusculus (Dana, 1852) of North American origin was introduced to Europe (to Scandinavia) in the 1960s. Since that time due to translocation to many countries, biological features and ecological plasticity, it became widespread, invasive and displaced native species. The paper reports first multi- point colonization of P. leniusculus in the Polish rivers. The aim of the study was to determine the current distribution of the signal crayfish in the coastal Baltic tributary (the River Wieprza) after 20 years of deliberate releases in its drainage area. During sampling at 28 sites with use of the “Pirate” crayfish traps and hand collection methods in spring and summer 2014, 127 P. leniusculus individuals were found at 8 sites in the Wieprza and its two tributaries, both away from and close to known sites of their introduction in 1995 and 1996 in the Wieprza River drainage area. The species spreads via the Wieprza River towards the Baltic brackish waters. With such expansion of this species, it is expected to be found in Polish coastal waters of the Baltic Sea and in other coastal rivers in the near future. The conflict between legal aspects of the signal crayfish farming, colonization by the species of the natural aquatic ecosystems and the expectations of consumers is discussed.

Screening of 17α-ethynylestradiol and non-steroidal anti-inflammatory pharmaceuticals accumulation in Mytilus edulis trossulus (Gould, 1890) collected from the Gulf of Gdańsk

Abstract Pharmaceuticals are commonly found in water collected from wastewater treatment plants, fresh water and saline water. Their presence in water may result in constant accumulation in living organisms, and consequently a negative impact on those organisms. Abiotic samples collected from the Gulf of Gdańsk were already proven to be polluted by several classes of pharmaceuticals, but the bioaccumulation was not investigated as far. This study presents the first results on the accumulation of pharmaceuticals in Mytilus edulis trossulus (Gould 1890) mussels collected from the Gulf of Gdańsk. The content of target 6 non-steroidal anti-inflammatory pharmaceuticals (ibuprofen, flurbiprofen, diclofenac, paracetamol, naproxen, ketoprofen) and 17α-ethynylestradiol in water and tissue samples was determined. The selected pharmaceuticals (paracetamol, flurbiprofen, 17α-ethynylestradiol) were found only in the largest individuals. The in situ BAFs calculated for paracetamol and flurbiprofen were 2850 and 16154 l kg-1 (dry weight), respectively, suggesting a high potential for the bioaccumulation of these compounds. The synthetic hormone 17α-ethynylestradiol was also found in the collected mussels at the concentration of 310 ng g-1 of dry weight. Generally, the examined mussels showed poor condition and it is highly likely that the accumulated pharmaceuticals are one of the important factors contributing to this.

The spiny-cheek crayfish Orconectes limosus (Rafinesque, 1817) as an inhabitant of the Baltic Sea — experimental evidences for its invasion of brackish waters

The main aim of the present study was to determine the effect of low salinity conditions (3 PSU and 7 PSU) on the hatching success, growth and mortality of Orconectes limosus. The results revealed that berried females survived exposure to salinities of 3 PSU and 7 PSU whilst incubating their eggs. The reproductive success reached 100% at both salinities. The length increment of young crayfish per molt was larger at 7 PSU than at 3 PSU — but their condition was affected by higher salinity. The mortality among juveniles reached approximately 50% within 5 weeks of hatching at both salinities.

Folliculinids - epibiotic ciliates from Puck Bay

Folliculinids - epibiotic ciliates from Puck Bay The present paper reports on the occurrence of the epibiotic ciliates of the family Folliculinidae Dons on the American crayfish Orconectes limosus (Raf., 1817). This is the first report of folliculinid ciliates from coastal waters of Puck Bay observed on animal substrata.

Spiny-cheek crayfish Orconectes limosus (Rafinesque, 1817) on its way to the open coastal waters of the Baltic Sea

Abstract The aim of this work was to assess the adaptive capabilities of the spiny-cheek crayfish Orconectes limosus (Rafinesque, 1817) in the open coastal waters of the Baltic Sea. The results could help to predict the likely further expansion of this species and its colonization of brackish waters. The following aspects were discussed in the paper: the occurrence of the species in the Polish coastal zone of the Baltic Sea, the plasticity demonstrated in the body size of individual crayfishes, food preferences, hemolymph osmolality and reproduction in waters of different salinities, which enable the species to colonize brackish waters. In the Vistula Lagoon (salinity 2-3 PSU), where the population of O. limosus is stable, the length of individuals ranged from 77 to 118 mm. These crayfish mostly fed on fodder; the second and the third food preferences were crayfish abdominal muscle and green algae. O. limosus is a hyper-regulator in freshwaters and at low salinities (up to 13 PSU), and a hyporegulator at higher salinities (14, 21, 28, 35 PSU). Laboratory studies showed that the embryonic development of O. limosus at salinities of 3 and 7 PSU was normal and a high level of reproductive success was achieved. Salinity of 3 PSU is more favorable for the development of juveniles than 7 PSU. It seems to be just a matter of time before this crayfish starts to form populations in the brackish, coastal waters of the Baltic Sea.