Baltic Brackish Water Research Articles

Horizontal transmission of the ectoparasite Gyrodactylus arcuatus (Monogenea: Gyrodactylidae) to the next generation of the three-spined stickleback Gasterosteus aculeatus.

In the parthenogenetic monogeneans of the genus Gyrodactylus Nordmann, 1832, the genetic diversity within or between hosts is determined by the relative roles of lateral transmission and clonal propagation. Clonality and limited transmission lead to high-amplitude metapopulation dynamics and strong genetic drift. In Baltic populations of the three-spined stickleback Gasterosteus aculeatus Linnaeus, the local mitochondrial diversity of Gyrodactylus arcuatus Bychowsky, 1933 is very high, and spatial differentiation weak. To understand the transmission dynamics in a single location, the transmission of the parasite from adults to next generation sticklebacks was investigated in a northern Baltic brackish water location. By sequencing 777 nt of cox1, as many as 38 separate mitochondrial haplotypes were identified. In August, the intensity of gyrodactylid infection on adult hosts was high, the haplotype diversity (h) was extreme and differentiation between fish was negligible (total h = 0.926, mean h = 0.938). In October, only 46% of the juvenile sticklebacks carried G. arcuatus. The number of parasites per young fish followed a Poisson distribution 0.92 ± 1.04 (mean ± SD) on October 2, and was clearly overdispersed 2.38 ± 5.00 on October 25. The total haplotype diversity of parasites on juveniles was nearly as high as in adults (h = 0.916), but the mean per fish was only h = 0.364 (FST = 0.60), due to low intensity of infection and rapid clonal propagation of early arrivals. The initial first come first served advantage of the first gyrodactylid colonisers will be lost during the host adulthood via continuous transmission. Nesting and polygamy are suggested as factors maintaining the high genetic diversity of the parasite population. The transmission dynamics and, consequently, the population structure of Baltic G. arcuatus is fundamentally different from that of G. salaris Malmberg, 1957, on the Baltic salmon Salmo salar Linnaeus.

Recovery from hypoxia with and without sulfide in Saduria entomon: potassium, ATP and behavior

The contribution of potassium pumping, tissue ATP levels and locomotory activity to the oxygen debt was studied in the Baltic brackish water isopod Saduria entomon recovering from hypoxic and sulfidic conditions. The isopods were exposed (8 h; 9°C; salinity 10 ppt) to hypoxia (0.3 kPa) and to hypoxia (1 kPa) with sulfide (45 µM) and allowed to recover from hypoxia (8 h) and sulfide (28 h). When exposed to hypoxia the hemolymph and tissue K+ concentrations decreased significantly. When allowed 8 h recovery, normoxic K+ concentration was restored in the tissue but not in the hemolymph. After exposure to sulfide the hemolymph K+ was not different from the normoxic level but tissue K+ decreased significantly. When allowed 28 h of recovery the tissue K+ concentration was restored but the hemolymph K+ was significantly decreased as compared to the normoxic value. The ATP level in the normoxic control showed a significant decrease with time, indicating a general decrease in metabolic activity. The ATP level was significantly decreased after exposure to both hypoxia and sulfide. When allowed to recover, the ATP level in sulfide was significantly increased as compared to the normoxic value, indicating the occurrence of repair processes. During recovery from hypoxia and sulfide S. entomon showed no increase in locomotory activity. In terms of oxygen equivalents, re-establisment of potassium concentration contributed approximately 25 and 20% to the oxygen debt paid after exposure to hypoxia and sulfide, respectively. The results are discussed in relation to their contribution to the oxygen debt in S. entomon recovering from hypoxic and sulfidic exposure and possible processes not yet identified.

Integrated ecological assessment of Danish Baltic Sea coastal areas by means of phytoplankton and macrophytobenthos

The Water Framework Directive (WFD) demands an integrated assessment of ecological quality based on biological parameters. In this context combined macrophytobenthos and phytoplankton data sets along the Danish Baltic Sea coast were analysed for similarities and differences in their response to abiotic variables. Zostera marina's depth limits showed a significantly negative correlation with concentrations of total-nitrogen, total phosphorus and chlorophyll a as well as with Myrionecta rubra biomass and a strongly positive correlation with Secchi depth. The results documented that selected phytobenthos and phytoplankton indicators show correlated responses to water quality. All biotic and abiotic parameters clustered in two groups, indicating two trophic states but, at the same time, also two distinct salinity classes. One class was characterised by low nutrient levels and low salinity while the other class was characterised by high nutrient levels and high salinity, indicating that the mixing of relatively nutrient poor brackish Baltic water with more nutrient rich North Sea water overruled traditional estuarine gradients in the investigated area. The results therefore allow an analysis of the eutrophication state regarding the additional influence of decreased salinity on euryhaline marine species. The consequences of the results are discussed in relation to classification systems for brackish water ecosystems.

Mitochondrial DNA variation in populations of the mussel Mytilus trossulus from the Southern Baltic

The mussel Mytilus trossulus is an important component of the Baltic brackish water ecosystem. The genetic structure of mussel (M. trossulus) populations was studied in sites along the Polish coast, Southern Baltic for two segments of mitochondrial DNA (mtDNA). The mode of inheritance of Mytilus mtDNA is termed doubly uniparental; two genomes are passed independently down the female (the F genome) and male (the M genome) lines of descent. The M genome has not been detected at high frequency in M. trossulus, thus the present study focuses on the F genome. PCR and RFLP analysis was used to characterise haplotypes in the coding region ND2-COIII; PCR was used to detect length variants in a major noncoding region. Significant differentiation between populations was observed in the frequency of 24 coding region haplotypes and 14 different length variants. For the three most frequent coding region haplotypes, two (I and III) are associated with the length variants, whereas the third (II) is monomorphic for a single variant of short length. It is suggested that variant II is derived by introgression from a related species, M. edulis, and may be resistant to expansion in the noncoding region. In both regions studied, the Ewens–Watterson test reveals significant deviations from neutrality with an excess of rare variants. This might be due to selection against slightly deleterious variants and is consistent with previously published results for Mytilus taxa. The present study also points towards the potential utility of mtDNA length variation in studies of population differentiation of Mytilus.

Evaluation of the anthropogenic influx of metallic pollutants into Puck Bay, southern Baltic

Distributions of 15 elements with depth in two sediment cores from Puck Bay in the Gulf of Gdansk show that Ag, Cd, Pb, Zn and possibly Cu and Ni are anthropogenically enriched in the sediments there. The concentrations of these elements decrease sharply with depth in the sediment column and the elements are preferentially enriched in the <2 μm size fraction of the sediment. The sequence of element enrichment depends on whether the enrichment factor (EF) and the anthropogenic factor (AF) are used to calculate the element enrichment. By contrast, the anthropogenic elements show no systematic decrease in concentration with depth in a sediment core taken from near the mouth of the Vistula River. This reflects the higher sedimentation rate there such that the entire upper 20 cm of the core was deposited during the major, post-war period of industrialization in Poland. In addition, these elements are enriched in the 2–63 μm fraction compared to the <2 μm fraction in these sediments. This suggests that the heavy metals are mainly adsorbed on Fe oxyhydroxide particles with diameters greater than 2 μm at the hydrological front where Vistula river water mixes with brackish Baltic water. It appears that heavy-metal pollution of sediments in parts of Puck Bay may be greater than that near the mouth of the Vistula River which may reflect, in part, the higher sedimentation rate near the mouth of the Vistula River. The mode of incorporation of heavy-metals into the sediments in the two areas may also be different.

Diurnal Changes in Arginine Vasotocin and Isotocin Plasma Levels in Rainbow Trout Adapted to Freshwater and Brackish Baltic Water

Diurnal Changes in Arginine Vasotocin and Isotocin Plasma Levels in Rainbow Trout Adapted to Freshwater and Brackish Baltic Water

Response of circulating arginine vasotocin and isotocin to rapid osmotic challenge in rainbow trout

The plasma levels of arginine vasotocin (AVT) and isotocin (IT) in rainbow trout ( Oncorhynchus mykiss) were studied to demonstrate changes in neurohypophysial nonapeptides following rapid osmotic challenge. Freshwater-adapted fish were transferred to brackish Baltic water (BW) and brackishwater-adapted fish were transferred to fresh water (FW). In both experiments blood samples for AVT, IT and osmolality were taken 30 min, 1, 2, 24 hr, and 10 days after transfer. Hormones were determined by gradient high-performance liquid chromatography preceded by solid-phase extraction. The pattern of AVT and IT response to external salinity changes was similar during the first hours and showed transient increase or decrease after transfer to brackish or fresh water, respectively. The AVT plasma concentration after 10 days in FW was significantly higher than that in BW, whereas the IT plasma concentrations in both salinities did not differ. These data suggest that the synthesis and or release of AVT and IT are controlled independently, and the roles of hormones in long-term osmotic adaptation are different.

Diurnal Changes in Plasma Arginine Vasotocin and Isotocin in Rainbow Trout Adapted to Fresh Water and Brackish Baltic Water

The plasma levels of arginine vasotocin (AVT) and isotocin (IT) in rainbow trout (Oncorhynchus mykiss) were studied to assess possible diurnal variations in neurohypophysial nonapeptides. Fish were kept under natural photoperiod and adapted to fresh and brackish Baltic water. Blood was sampled at 5:00, 11:00, 16:00, 22:30, and again at 5:00. Hormones were determined by gradient high-performance liquid chromatography preceded by solid-phase extraction. The marked diurnal changes of AVT were detected in plasma of fish adapted to both fresh and brackish waters. AVT levels (fmol/ml) were maximal at 16:00 and minimal at 5:00 (253.4±35.7 and 45.5±17.3, respectively). Unlike AVT, isotocin levels displayed no diurnal changes. AVT concentrations at 11:00, 16:00, and 22:30 were significantly higher than IT values measured throughout the day. Plasma AVT concentrations determined in brackish water-adapted fish at 16:00 were significantly lower than those of freshwater-adapted fish at the same time. These data suggest that synthesis and/or release of AVT and IT are controlled independently, so that these nonapeptides have different physiological roles in teleost fish. AVT might participate in circadian time-keeping system in fish.

Recovery from hypoxia with and without sulfide in Saduria entomon:oxygen debt, reduced sulfur and anaerobic metabolites

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 143:131-139 (1996) - doi:10.3354/meps143131 Recovery from hypoxia with and without sulfide in Saduria entomon: oxygen debt, reduced sulfur and anaerobic metabolites Vismann B, Hagerman L The Baltic brackish water isopod Saduria entomon was exposed (8 h; T: 11°C; S: 10 ppt) to hypoxia (0.1 kPa) and to hypoxia (0.7 kPa) with sulfide (41 µM). Oxygen consumption was measured using computer-controlled intermittent respirometry. The routine oxygen consumption was 0.109 mg O2 h-1 g-1 at normoxia (19.5 kPa). The recovery from hypoxia with and without sulfide was studied in terms of oxygen debt, reduced sulfur concentration and anaerobic metabolites. In hypoxia, the metabolism of S. entomon was reduced by 70% compared to the normoxic level and the oxygen debt was 0.57 mg O2 g-1. Normal respiration rate was re-established after 8 h of recovery. Lactate oxidation accounted for 44% of the oxygen debt. In hypoxia with sulfide, the metabolism was reduced by 38% compared to the normoxic level and the oxygen debt was 2.74 mg O2 g-1 (5 times the oxygen debt at hypoxia). Normal respiration level was not restored until 28 h after exposure. Lactate oxidation accounted for only 20% of the oxygen debt. Sulfide and detoxification products accounted for as little as 0.04% (1 µg O2 g-1 wet wt) of the oxygen debt. The majority (80%) of processes that occurred during the recovery from sulfide exposure are inferred to be involved in restoring normal cell function. Removal of internal sulfide and reoxidation of anaerobic metabolites play secondary roles. Sulfide · Hypoxia · Recovery · Oxygen debt · Anaerobic metabolites · Saduria entomon Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 143. Publication date: November 14, 1996 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1996 Inter-Research.

Anaerobic metabolism, hypoxia and hydrogen sulphide in the brackish water isopodSaduria entomon(L.)

Abstract The Baltic brackish water isopod Saduria entomon was simultaneously exposed to hydrogen sulphide (150 µmol 1−1 ) and hypoxia (4.0-6.7 kPa) for up to 100 hours. In contrast to haemoglobin-carrying species, the haemocyanin of S. entomon functions as oxyhaemocyanin also in the presence of hydrogen sulphide. The synthesis of new haemocyanin is, however, prevented. The hydrogen sulphide is oxidised in the midgut gland to S2O3 2− and SO3 2− Both lactate and alanine accumulate in the presence of hydrogen sulphide. When exposed to hypoxia and hydrogen sulphide anaerobic end products start to accumulate already at a water oxygen tension of at least 4.0–6.7 kPa, this means that hydrogen sulphide is correlated with an anaerobic metabolism.

Magnetic susceptibility in sediment records of Lake �dran, eastern Sweden: correlation among cores and interpretation

Magnetic susceptibility was used to test the representativity of the lithostratigraphy of a master sediment sequence from Lake Adran, eastern Sweden. Five further sediment cores from the same lake were correlated and compared with the master sequence using magnetic susceptibility records. Mineral magnetic correlations are generally based on matching prominent susceptibility features but may be significantly improved by using slot sequence analyses. The result of these analyses show that the sediment in the Lake Adran master sequence can be considered representative for the basin. The variations in the magnetic susceptibility in relation to pollen and diatom analyses also seem to reflect water level changes and shore displacement in the Baltic between 9900 14C years B.P. and the isolation at 5900 14C years B.P. The first emergence of scattered non-vegetated islands is characterised by high susceptibility values. Along with a continuous water lowering and the development of the vegetation during the Ancylus fresh water stage, susceptibility values gradually decrease. A rapid phase of the Ancylus regression between 9200 and 9000 14C years B.P. is seen as an increase in magnetic susceptibility. During the following Baltic brackish water stage, the Litorina stage, susceptibility values are at their lowest, followed by higher values at the isolation from the Baltic with a maximum around 5000 14C years B.P. Shore displacement between 9900 and 5900 14C years B.P. is discussed based on the magnetic susceptibility measurements and their relationship to the pollen and diatom analyses.

Temperature selection behaviour of the isopod Saduria entomon (L.)

1. 1|The behaviour of stenothermal cold water isopods Saduria entomon (L.), kept in their native Baltic brackish water (salinity 6‰) at 4°C was analysed in a toroidal thermal gradient. One animal at a time was studied in the gradients extending from 2 to 17°C and from 9 to 24°C. 2. 2|The animals selected the temperatures at around 15°C in both of the gradients. At the selected temperature, they settled down through thermotactic (or thermoklinokinetic?) behaviour, i.e. by doing 180° turnings in the gradient and through orthokinetic behaviour, i.e. by a low motility at the selected temperature. 3. 3|In the gradient from 2 to 17°C, the animals selected temperature of about 15°C very distinctly, but at the higher temperature gradient, their distribution at rest was fairly even. 4. 4|The results suggest that high temperature seeking behaviour of Saduria may be important in their life at low temperatures.

Seasonal variations in some blood parameters in perch, Perca fluviatilis L.

Summary Clinical blood tests on fish exposed to contaminants are used extensively both in laboratory and field studies. Seasonal variability is examined in some of the parameters commonly used in health assessments. Hematocrit, hemoglobin concentration and inorganic ion concentration were studied in perch, Perca fluviatilis, from a Baltic brackish water area. Seasonal cycles were demonstrated in hematocrit and in chloride, magnesium and potassium ion concentrations. Other parameters studied reacted irregularly or only slightly to the shift of seasons.

Aspects of osmotic and lonic regulation in two Baltic teleosts: Effects of salinity on blood and urine composition

Hydromineral regulation was studied by examining the response to different environmental salinities in two Baltic brackish-water (BW) teleosts—a species of marine ancestry, Myoxocephalus scorpius (L.), and a glacial relict, M. quadricornis (L.). M. scorpius tolerated fresh water (FW) and M. quadricornis sea water (SW) for only about 24 h, but the survival time of M. scorpius in SW and M. quadricornis in FW was one to several weeks. M. scorpius seems able to balance plasma ionic concentrations in salinities down to about 2 to 3‰. Death of M. scorpius in FW was associated with partial haemolysis, increased volume of red blood cells (RBC), increased plasma K+ concentration, and decreased concentrations of Na+, Cl- and Mg2+ in plasma and, to a lesser extent, in urine. Death of M. quadricornis in SW was associated with increased plasma osmolality, and Na+, Cl- and Mg2+ concentrations, but the renal excretion of ions approached that generally found in marine teleosts. In most cases, RBC volume followed the changes in plasma osmolality or Na+ and Cl- concentrations. Both species showed an ability to increase tubular Mg2+ secretion much over that needed in BW, and increased secretion was associated with high urine Cl- concentration. M. quadricornis, but not M. scorpius, reabsorbed Na+ effectively in SW also. Differences between Oceanic and Baltic specimens of M. scorpius are discussed.

Measurements of Community Metabolism in Some Baltic Brackish Water Rockpools by Means of Diel Oxygen Curves

Estimates of community metabolism have been made in some Baltic brackish water rockpools by means of the diel oxygen technique. The rockpools are especially suitable for this method because of their well-defined and usually unstratified water bodies. Primary production values (gross photosynthesis) of between 2.7 and 21.8 g 02 m-2 day-1 and community respiration values between 2.7 and 18.2 g O2 i-M2 day-1 were recorded. Variations between individual pools could be explained by deviations in geomorphology and biology. These productivity figures, measured during the summer, are high, even compared with tropical shallow water ecosystems. Photosynthesis exceeds respiration in all the pools and these autotrophic conditions are generally found throughout the year in spite of a heavy load of nutrients and a limited exchange of water with the sea. The photosynthetic efficiency is highest in the early afternoon in pools with dominating benthic macrofiora but in the morning and later afternoon hours in pools with dominating planktonic microalgae. A Lemna cover on the surface of a pool effectively prevents metabolic processes in the water, measurable by the method used.

SALINITY REACTIONS OF SOME FRESH- AND BRACKISH-WATER CRUSTACEANS

1. The salinity reactions of Asellus aquaticus from fresh and Baltic brackish water (6‰), of Idotea baltica and of Gammarus spp. from brackish water were studied with the apparatus of Hodgson (1951). Both natural brackish-water and pure NaCl solutions were used.2. None of the experimental animals had, for brackish water, reaction thresholds low enough to allow behavioral selection of salinities to occur in natural conditions.3. The reaction threshold for NaCl solutions was higher in brackish-water than in fresh-water specimens of Asellus. Asellus always preferred the more dilute concentration. Idotea baltica and Gammarus preferred brackish water to fresh water. Gammarus preferred even 6‰ NaCl to fresh water.4. In Asellus, the chemoreceptors mediating the response to salinity variations seem, for the most part, to be situated on the antennae and/or antennulae. In Gammarus, the salinity receptors are situated on the antennae and antennulae.

III.—The Recent Geological History of the Baltic and Scandinavia and its importance in the Post-Tertiary History of Western Europe

We will now try and picture to ourselves how the circulation of the water was affected by the breach in the land bridge. We have seen in the earlier part of these papers that one of its effects was that the southern and western part of the Baltic became rapidly richer in marine forms. This is because the Straits between Gjedserodde in the island of Falster and Darrserort on the mainland of Mecklenburg form a great barrier to the eastern migration of the marine mollusca, whose species increase greatly in numbers when we pass westward of them. This seems to again point to the fact that the inflow of salt waters into the Baltic from the North Sea passes chiefly through the deeper Belts and not through the shallower Sound, which is the chief outlet of the more brackish Baltic water. On the other hand, the Swedish side of the sea remains poor in fauna until we reach the latitude of the island of Saltholm, due partly to its greater shallowness, which only allows a smaller proportion of the incoming North Sea water to pass.