Southern Coast Of Finland Research Articles

Effects of winter weather conditions on abundance fluctuations in a nest box breeding population of the Common Merganser Mergus merganser in the southern coast of Finland

Effects of winter weather conditions on abundance fluctuations in a nest box breeding population of the Common Merganser Mergus merganser in the southern coast of Finland

Implications on crustal structure from the South Finland Coastal (SOFIC) deep seismic sounding profile

We present results from a deep seismic sounding (DSS) experiment carried out along the southern coast of Finland in summer 2015. Data used in the survey derived from industrial blasts recorded by temporary project stations and permanent network stations. The western 220 km part of the 450 km long Southern Finland Coastal (SOFIC) profile runs along the Uusimaa belt (UB) in the 1.7–1.9 Ga Southern Finland subprovince (SFS) of the Svecofennian domain, while the 170 km part in the east crosses the 1.62–1.65 Ga Wiborg rapakivi batholith (WRB). The farthest 60 km cross a geologically diverse area consisting of supracrustal rocks and granitoids of the Saimaa area (SA), an eastern extension of the SFS. Our results show that the Moho boundary depth varies significantly, from ca. 52–54 km below UB to 40–45 km below WRB. All three crustal layers (upper, middle, and lower) have their maximum depth in the contact zone between UB and the WRB. Below WRB, a lower crust with Vp ~6.7–6.9 km/s is observed. High velocity lower crust was observed below UB (Vp ~7.2 km/s) and possibly below SA (Vp ~7.35 km/s). The modelling was based on ray tracing, using the extrapolation of seismic wave arrival times with the help of travel times predicted from a one-dimensional velocity model. The resulting two-dimensional velocity model partly relies on data from the intersecting DSS profiles and supports previous observations of the lithospheric structure of southeastern Fennoscandia.

Body Condition in the Tawny Owl Strix aluco near the Northern Limit of Its Range: Effects of Individual Characteristics and Environmental Conditions.

Simple SummaryThe present study examines how the variations in food supply and winter weather are reflected in the body condition of female and male Tawny Owls Strix aluco of different colour morphs in a population near the southern coast of Finland. Winter weather conditions before breeding seemed to have effects on the food availability of Tawny Owls: the depth of the snow cover showed a positive relationship, and the frequency of temperature fluctuations around the freezing point had a negative relationship. In females, intrinsic factors such as colour morph and age, as well as the body condition of the mate and the stage of the season, governed body condition. In males, only age and the stage of the season suggested associations with body condition. Probably due to the efficient use of alternative prey, the effects of fluctuations of vole populations on the body condition of Tawny Owls are only moderate.The body condition of boreal species of vole-eaters seems to vary largely according to fluctuations in vole populations and weather conditions of the preceding winter. I studied females and males of the Tawny Owl Strix aluco of temperate origin near the northern limit of the species’ range in southern Finland to reveal if they show similar patterns to the boreal species. Winter weather conditions before breeding seemed to have pronounced effects on the food availability of Tawny Owls. In females, intrinsic factors such as colour morph and age, as well as the body condition of the mate and the stage of the season (Julian date), governed body condition. In males, only age and Julian date showed pronounced relationships with body condition. The results suggest that deep snow cover protects vole populations through winter until spring better than a minor amount of snow and that frequent temperature fluctuations around the freezing point in early spring make voles more available for owls that are preparing for breeding. This was also reflected positively in the body condition of female owls. Probably due to the efficient use of alternative prey, the effects of fluctuating vole populations on the body condition of Tawny Owls are, in general, only moderate.

Does plumage colour signal fitness in the tawny owl Strix aluco?

Plumage colour has been hypothesized to signal fitness in its component parts survival and reproduction. In the tawny owl Strix aluco, grey individuals have been considered to be more viable and productive than brown ones in cold environmental conditions. The recent increase in the frequency of the brown morph in Finland has been explained by the climate warming. However, in recent decades there have been no trends in the general mildness of winters. Therefore, trends in the abundance of owls due to climate warming per se were unexpected. In a population near the southern coast of Finland, the abundance of grey (not brown) individuals increased significantly during the period 1986–2018, suggesting that natural selection has recently favoured the grey colour morph. During snowy and cold winters grey owls seemed to survive better than brown ones, suggesting that plumage colour signals adaptations to winter weather. The proportion of brown individuals in each year was best explained by the joint effect of snow cover and winter temperature. Extreme peaks in snow fall and cold winters seemed to affect substantially and rather similarly the abundance of both colour morphs. Between population differences in the occurrence of colour morphs were probably due to local and temporal differences in the snow cover. The number of fledglings was significantly related to the colour morph and weather conditions of the preceding winter in males but not in females. This suggests that coloration of males signals fitness in reproduction.

Diplodia sapinea found on Scots pine in Finland

AbstractDiplodia sapinea is an important pathogen of Pinus spp. in many parts of the world's temperate and sub‐tropical zones. In Central Europe, this fungus has been known since its first description in the 19th century. But it was only in 2007 that the fungus was identified using DNA‐markers in northern Europe (in Estonia). Viljo Kujala reported observing D. sapinea on logging debris of Norway spruce in Finland in 1945, but we have not been able to verify the identifications from his herbarium samples. In 2004, we collected cones under asymptomatic Scots pine (Pinus sylvestris) trees at one location near the southern coast of Finland but failed to isolate D. sapinea from the samples. In 2015 and 2016, we collected fallen Scots pine cones in 15 Scots pine stands in various parts of Finland and the fungus was found at five locations in southwestern Finland including the location investigated in 2004. Frequency of cones with pycnidia of D. sapinea varied from 1% to 12% in the infested stands. No symptoms of Diplodia tip blight or resinous cankers were detected in trees in the stands where the cones were collected. The results suggest a recent introduction after 2004 of the D. sapinea in Finland.

An allostratigraphic approach to subdivide fine-grained sediments for urban planning

Fine-grained sediments in southern Finland were deposited during the retreat of the continental Fennoscandian ice-sheet at around 13,000 cal BP, leaving subsequent ice-contact deposits and postglacial lake and, finally, the modern brackish water Baltic Sea basin (BSB). As a result of the strong glacioisostatic land uplift of the region, these sediments today lie above sea-level in coastal Finland. The recent expansion of cities to locations where superficial sediments are more challenging for construction purposes has increased the need for comprehensive understanding of the properties and geometry of these fine-grained superficial deposits. Commonly used site-specific lithostratigraphical characteristics of clayey deposits run the risk of ambiguous correlation between sites because of different types of postglacial depositional settings. The present study applies an allostratigraphical approach to classify late- and postglacial clayey deposits using examples from four sedimentary basins in the vicinity of the city of Espoo along the southern coast of Finland. This entails a reinterpretation of 17 core logs collected during the period 2006–2009 and reported in earlier studies, combined with examination of five new cores collected in 2016 coupled with borehole measurements of resistivity-temperature and electrical resistivity tomography (ERT). Physical proxies and sediment characteristics demonstrate that grey postglacial lacustrine silty (Ancylus Lake) clay is truncated at the top by an undulating erosional surface (unconformity), which is covered by a silt to sand layer a few centimetres thick that has a gradual-bioturbated upper contact to the greenish-grey brackish water (Litorina Sea) mud. Sediments above and below the unconformity are intensely bioturbated, and black mottling of Fe-monosulphide is observed in the brackish water mud. Evidently, this unconformity is of high engineering-geological significance because the organic-rich brackish water mud has a poorer bearing capacity and higher abundance of sulphide minerals that form sulphuric acid upon oxidation. It is demonstrated that this unconformity is spatially well recognised and provides a key stratigraphic marker for wider and more accurate comparison between sites with fine-grained deposits in the Helsinki metropolitan area and potentially in other urban areas in the northern Baltic Sea region.

Sediment and carbon accumulation rates off the southern coast of Finland

The southern coast of Finland encompasses about one third of the coasts of the Gulf of Finland. It is a mosaic of hundreds if not thousands of islands, peninsulas and bays, which also are reflected in the seabed of the coast. The sea floor is composed of a patchy and fragmented mosaic of mainly quite small basins separated from each other by thresholds of islands, peninsulas or submarine ridges. This affects transport and near bottom currents such that deposition of suspended particles is restricted to certain areas only. Linear sediment accumulation rates along the southern coast of Finland were studied from 28 cores of a sampling campaign in 2000 – 2004 through gamma spectrometry of 137Cs. Sediment accumulation in this environment with such diverse character was found very patchy and net sedimentation rates varying from less than 0.5 cm/a to values of nearly 3 cm/a as well as mass accumulation rates from 0.5 kg/m2/a to 8.8 kg/m2/a were found. The sediment accumulation rates were observed to be higher in shallower water in coastal sheltered or semi-sheltered bays. Total carbon concentrations varied from 1.3 % to 12.6 % and carbon accumulation rates from 20 g/m2/a to 355 g/m2/a such that the highest carbon concentrations were usually found in deeper water with some distance from the coast, while the highest carbon accumulation rates were found in the coastal shallow basins where sediment accumulation was found strongest.

Benthic conditions around a historic shipwreck: Vrouw Maria (1771) in the northern Baltic proper

Since her shipwreck in 1771, the wooden vessel Vrouw Maria has been lying on the seabed at 41m depth on the border between the Archipelago Sea and the northern Baltic proper, off the southern coast of Finland. The wreck lies in an upward position in a right angle to the dominating bottom current, which is potentially affecting seabed topography, sediment characteristics and zoobenthic communities both upstream (NE) and downstream (SW) of the wreck. This multidisciplinary study attempts to clarify abiotic and biotic patterns and processes in the vicinity of the wreck by combining field investigations with physical simulation studies in the field and in the laboratory. Multibeam echo-sounder techniques were utilised to generate a map of the wreck area and sediment grab samples were taken to characterize the sediment type and its zoobenthic community. A medium-sized field experiment generated data on the accumulation of sediment organic matter in the presence and absence of a current and/or a barrier on the seafloor and a small-scaled laboratory study was conducted to simulate scour forming processes.The results showed that a deeper basin, scour area, with the dimensions 150×300m, was present downstream of the wreck and there was also a smaller scour area upstream of the wreck. Similar traces on the bottom were simulated in the laboratory. The organic content (recent mud) and the proportion of finer sediment were more pronounced in areas closer to both sides of the wreck. These results were in turn imitated in a field experiment, where the accumulation of organic matter in the sediment increased significantly downstream, when a current was interrupted by a barrier. Regarding zoobenthos in the wreck area, 11 taxa and a mean total abundance of 773 individuals per m2 were registered. The dominant species were Macoma balthica and Marenzelleria sp., which together made up >80% of the total number of individuals. Multivariate data analyses showed significant differences in community structure between upstream and downstream sides of the wreck and these differences were basically expressed as more individuals upstream of the wreck of the seven most common species. Univariate data analyses also showed significantly more species and higher total abundance in the scour area upstream of the wreck compared to the downstream scour area. The weakened communities downstream of the wreck were possibly due to accumulation of organic matter and more frequent occurrence of hypoxia. The results are useful for describing bottom areas around long-term physical barriers/artificial reefs, as background measurements ahead of possibly increased archaeological diving activities, sediment excavations or measures taken to raise the wreck to the surface, as well as for any attempts to preserve the wreck in situ.

More evidence that anaerobic oxidation of methane is prevalent in soils: Is it time to upgrade our biogeochemical models?

Estimating future fluxes of CH4 between land and atmosphere requires well-conceived process-based biogeochemical models. Current models do not represent the anaerobic oxidation of methane (AOM) in land surface soils, in spite of increasing evidence that this process is widespread. Our objective was to determine whether AOM, or potential AOM, commonly occurs in 20 hydromorphic soils spanning a wide range of chemical properties. Bulk soil samples were collected under shallow water near the shoreline of 15 recently drained fish ponds in southern Bohemia (Czech Republic), as well as from below the water table at 3 peatland locations in northeast Scotland and 2 acid sulfate soils on the southern coast of Finland. Each soil slurry was incubated under both oxic and anoxic conditions, with or without the addition of alternative electron acceptors (SO42− and NO3−) or H2PO4−. Here, “oxic” and “anoxic” conditions refer to anoxic soil respectively incubated in a headspace containing air or argon. Using the isotope dilution method, we determined the gross production and oxidation rates of CH4 after 2 days incubation under oxic headspace conditions, and after 2, 21 and 60 days incubation under anoxic conditions. Large differences in net CH4 fluxes were observed between soil types and between incubation conditions. AOM was detected in each of the 20 bulk soil samples, which spanned >6 pH units and 2 orders of magnitude in organic C content. Significant positive relationships were found between AOM and gross CH4 production rates under anoxic conditions, resulting in AOM rates that were sometimes higher than CH4 oxidation rates under oxic headspace conditions. There was no relationship between net and gross CH4 production rates, such that 2 soil types could display similar low net rates, yet conceal very large differences in gross rates. The effects of alternative electron acceptors on AOM were idiosyncratic and resulted in no net trend. We did find, however, a negative effect of SO42− and H2PO4− on gross CH4 production rates under anoxic and oxic conditions respectively. Under oxic headspace conditions, CH4 oxidation was related to soil organic C content. Taken collectively, our results suggest that AOM, or potential AOM, is prevalent over a wide range of soil types, that AOM may contribute substantially to CH4 oxidation in soils, and that AOM in soils should be integrated to current process-based CH4 cycling models.

The history of settlement on the coastal mainland in Southern Finland. Palaeoecological, archaeological, and etymological evidence from Lohjansaari Island, Western Uusimaa, Finland

According to earlier views, the southern coast of Finland was a peripheral area until the 12th and 13th centuries, when Swedish colonists arrived with technological advances and the maritime landscape could be settled. In the course of multidisciplinary work over the past ten years, plenty of new data has been collected, and it should no longer be assumed that the area was empty before the Swedish colonization. In order to better understand the settlement history in the zone between the coast and the inland, we studied the small island of Lohjansaari, which is situated in the large lake of Lohjanjärvi, approximately 62 km northwest of Helsinki.The evidence from archaeology, palaeoecology, and etymology suggests that sedentary settlement based on agriculture became established on the NE shore of Lake Lohjanjärvi by the beginning of the Viking Age at the latest, and the island of Lohjansaari has been used for resources from about AD 570 onwards. A major change towards an open cultural landscape was dated on the island of Lohjansaari to about AD 1095. In general, this dating agrees with former pollen analyses from the coastal areas, where the shift to a fully agrarian landscape becomes visible starting from the period between AD 940 and 1100. A change interpreted as a shift to a two-year crop rotation system took place from AD 1250 onwards.

Palaemon elegans Rathke, 1837 (Caridea: Palaemonoidea: Palaemonidae) established in the Gulf of Finland

New observations are presented on the distribution of Palaemon elegans Rathke, 1837 in the Gulf of Finland and in the Archipelago Sea. P. elegans has spread and become established in the north-eastern Baltic Sea. Ovigerous females and juveniles were found, indicating that P. elegans reproduces in this area. The species was recorded, sometimes in high densities, along the southern coast of Finland between Naantali and Loviisa. Information on the distribution of P. elegans along the Estonian coast is also included.

Management mitigates the impact of urbanization on meadow vegetation

Urban regions often contain remnants of ecologically valuable habitats. Whilst meadow habitats have been recognized as ecologically important and much studied, little attention has been given to meadow assemblages of urban locations. We studied the effects of meadow type, urbanization level, and management on vascular plant species richness, field layer diversity and soil chemistry in 18 grassland sites in the Helsinki Metropolitan Area (60°E, 25°N), on the southern coast of Finland during the summer of 2007. We recorded a total of 252 species, though the average number of species per m2 was only 12.6. The negative effects of urbanization on forbs seemed to result in particular from increased soil nitrate (NO 3 - -N) concentration. The highest NO 3 - -N and Fe concentrations and ratios of total inorganic nitrogen (Ntot) to phosphorus (P) and potassium (K), were recorded from the soils of urban rocky meadows. Management by mowing decreased soil NO 3 - -N and Fe concentrations, ratios of Ntot:P and Ntot:K, and increased species richness and diversity. Elevated NOx deposition is considered as a major driver of urbanization effects on vegetation, though changes in soil pH and metal concentrations, such as zinc (Zn), may also negatively affect the frequency of both forbs and grasses. This study shows that regular management by mowing and removal of hay mitigates these effects. We also recommend increasing the provision of dry meadows and maintaining more areas of supplementary semi-natural grassland habitats in urban green space as concrete measures for the conservation of dry meadow assemblages and urban biodiversity.

Large-scale climatic phenomena and timing of breeding in a local population of the Osprey Pandion haliaetus in southern Finland

The effects of large-scale climatic phenomena on the timing of breeding in the Osprey Pandion haliaetus were studied during 1981–2006 in a small local population of about 20 pairs near the southern coast of Finland. The timing of breeding was estimated on the basis of the wing length of the largest young within the brood. The wing lengths were plotted against the date of the measurement to get a linear regression model characterizing the average developmental stage of broods in relation to date. This model was used when converting the measurements to correspond to the median date of all the measurements. Large-scale climatic phenomena were characterized by the winter and monthly indices of the North Atlantic oscillation (NAO). A significant positive relationship between the winter NAO index and timing of breeding in the Osprey, as indicated by the wing length of the largest young in the brood, was found. The relationship was even stronger when only the monthly value of January was considered. These relationships seemed to be linked with consequent earlier ice melting after mild winters. The results indicate prominent effects of large-scale climatic phenomena and that they can be monitored with relatively modest effort.

Late Holocene sea-level changes along the southern coast of Finland, Baltic Sea

Lake isolation studies provide a reliable method for reconstructing the sea-level history of areas affected by the glacio-isostatic land uplift. In this study, Late Holocene relative sea-level changes were investigated along the southern coast of Finland, Gulf of Finland in the Baltic Sea, by studying 11 isolation basins in four areas (Kirkkonummi, Orslandet, Tenhola and Prästkulla), which extend across 120 km of Finnish coastline that is characterised by a narrow archipelago. The methods employed were lithostratigraphic interpretation, diatom analyses and radiocarbon dating. Also used in this work are the results from three previously studied isolation basins with four 14C dates. The sea-level history varies within the study area. The 3000 yr old Baltic Sea shoreline is located about 11 m above present sea-level (a.s.l.) in Prästkulla, and about 8 m a.s.l. in Kirkkonummi. These differences are due to the differences in isostatic uplift rates, which have been slower in the east. The main trend in relative sea-level along the southern coast of Finland is one characterised by a generally decreasing uplift rate during the Late Holocene. However, we identify the uplift anomalies in two areas where our data show phases of relative sea-level lowering. They are the first verified Late Holocene land uplift anomalies detected in Finnish sea-level data.

Biomarkers of pollution effects in the bivalves Mytilus edulis and Macoma balthica collected from the southern coast of Finland (Baltic Sea)

ABSTRACT: Levels of selected biomarkers in 2 bivalve species, the hard-bottom filter-feeder Mytilusedulis and the infaunal deposit/suspension-feeder Macoma balthica were measured in 2 areas (Tvar-minne and Turku Archipelago) in the southern coast of Finland. The bivalves were collected for themeasurement of acetylcholinesterase (AChE), glutathione-S-transferase (GST) and catalase (CAT)activities, and for the determination of metallothionein (MT) content. The content of organochlorines(8 PCB congeners, DDE, DDD, DDT, HCH, HCB, dieldrin) and selected heavy metals (Cd, Cu, Hg,Zn) were measured in the soft tissues. In M. balthica collected from the Turku Archipelago region,biomarker gradients were observed in MT, GST and CAT, mostly coinciding with the tissue concen-trations of total PCBs, DDTs and selected metals. In M. edulis the biomarker responses were less con-sistent with regard to tissue pollutant concentrations. In the Tvarminne region no marked biomarkergradients were observed. The levels of all biomarkers varied significantly between the two species.The integrated biomarker response (IBR) index showed good accordance with the observed high tis-sue levels of organochlorines at the northern Airisto station in both species. This study is the first ofits kind performed in the coastal waters of Finland, and the results clearly demonstrate the usefulnessof the multibiomarker approach. Moreover, the use of 2 sessile species with markedly differing feed-ing modes and living habitats is considered a rational strategy for assessing the pollution status ofcoastal sea areas.KEY WORDS: Biomarkers · Baltic Sea · Bivalves ·

Fledgling production and population trends in Finnish common eiders (Somateria mollissima mollissima) — evidence for density dependence

We present a 57-year time series of a common eider, Somateria mollissima mollissima (L., 1758), population from one of the core monitoring areas in the Baltic Sea, the Söderskär bird sanctuary, Gulf of Finland. We applied permutation tests to inspect the relationships between breeding parameters and population density. Of the parameters studied, only fledging rate (during a 34-year period) showed a significant negative relationship with population size, indicating density dependence. Furthermore, the fledging rate responded strongly to the population growth rate and to the rate of recruitment. Clutch size and duckling (downy young entering the water) rate did not show negative density dependence. Thus, losses during brood rearing seem to be the regulatory factor. The population decline at Söderskär is similar to those recorded in many other monitoring sites around the southern coast of Finland. Compared with data from more productive sea districts in northwestern Europe (Dutch Wadden Sea and Scottish North Sea), the Finnish fledging rates do not seem excessively bad. There are indications of viral infections playing an increasingly central role in duckling mortality, whereas adult female mortality has not been affected.

For the quality of life - evolution of and lessons learnt from water and sanitation services in Porvoo, Finland, 1900-2000

The paper describes and analyses the 100 year development of water supply and sanitation and the lessons learnt in Porvoo, a municipality of 46,000 people on the southern coast of Finland. In urban areas the municipality-owned utility has always dominated. Over 90 per cent of the investments for the recent wastewater treatment plant went into services, equipment and goods bought from the private sector through 12 tenders, all based on competition. In the neighbouring rural areas, recently merged with the city, there are nine consumer-managed, non-profit water cooperatives that buy water in bulk from the city water utility. Although the solutions are based on local conditions and subsidiarity, some more general principles are also highlighted and discussed. Past decisions inevitably also affect future development options.

Evaluation and control of eutrophication in Helsinki sea area with the help of a nested 3D-ecohydrodynamic model

Helsinki is located on the southern coast of Finland by the Baltic Sea. The ecological state of the archipelago in front of Helsinki is affected by several factors. The effects of local point and scattered loads are mixed with the transboundary effects from neighbouring countries and atmospheric deposition. Municipal waste waters of 800000 inhabitants of the capital area are released outside the archipelago into the open Gulf of Finland (GoF). In addition, river Vantaanjoki is transporting load originating from agriculture, industry and settlements of the drainage area to the shores of Helsinki. Toxic algal blooms and annoying filamentous algal mats have become a problem to the users of the coastal zone.A local nested 3D-hydrodynamic model with water quality and ecosystem modules was set up in the Helsinki sea area. The model gives us an opportunity to examine ecosystem processes in a simplified format. The whole Gulf of Finland is included into the calculation area with low resolution (5000 m) increasing in two steps towards the coastal area around Helsinki (1000- and 250-m resolution). The model calculates water flows, transport of nutrients and growth of two groups of phytoplankton and one group of littoral filamentous algae. For model validation, a measurement program was carried out (flows, nutrients, chlorophyll-a, littoral filamentous algal biomass).Two nutrient load reduction scenarios were analysed with the validated model. The first scenario describes planned improvements in the efficiency of Helsinki municipal wastewater treatment, and the second scenario decrease in riverine load from the drainage area. The wastewater scenario decreased both phytoplankton and filamentous algal biomass by 5–15% in the vicinity of the outlet located in the outer archipelago of Helsinki. Changes in the inner archipelago and close to the shoreline were hardly detectable. The effects of the agriculture scenario on the algal biomasses stayed mainly below the arbitrarily selected detection limit of 2%. The reason for low impact is probably the effective transport of the riverine nutrients out of the estuary. The water of river Vantaanjoki has a very high concentration of suspended solids making the growth of both phytoplankton and filamentous algae clearly light limited in front of the river mouth. Low light availability decreases the algal growth and nutrient uptake allowing an effective transport of even highly biologically available nutrients. When the nutrients are transported and diluted into a large area, also the effects of load reductions easily fade below the detection limit.

PCDD, PCDF, PCB and thiamine in Baltic herring (Clupea harengus L.) and sprat [ Sprattus sprattus (L.)] as a background to the M74 syndrome of Baltic salmon (Salmo salar L.)

Baltic herring and sprat were sampled between October 1994 and January 1995 off the southern coast of Finland and around the Åland Islands. From this material fish of 135–159 mm in length, a size class that was assumed to be preferred as prey by Baltic salmon, were selected and grouped according to species, sex and age. Herring were 1–3 years and sprat 3–13 years old. In addition, one group of smaller, two-year-old, female sprat was selected. Thus twenty groups were formed and prepared as whole-fish homogenates. Thiamine was quantified from all homogenates, while female and male sprat and female herring were analysed for polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). There were no significant differences between sexes within each species in the total thiamine concentrations, but the mean total thiamine concentration in 1 to 3-year-old herring (8.6 nmol g −1 ) was higher than that in 2 to 13-year-old sprat (6.7 nmol g −1 ). The mean-fresh-weight concentrations of total PCBs, coplanar PCBs, PCDDs and PCDFs were on average 2–3 times higher in 2 to 10-year-old sprat than in 1 to 3-year-old herring of a similar size, although the difference in PCDD concentrations was not significant. In sprat females there were no significant correlations between age or fat content and the fresh-weight concentrations of coplanar PCBs or PCDFs. However, the higher OC concentrations in sprat could be explained both by their higher fat content, with the younger age groups being the most fatty, and by their age, which reflects their slower growth rate. The fat-weight-based total PCB, PCDD, PCDF and coplanar PCB concentrations increased with age in sprat and, after controlling for age, there was a significant positive relationship between the fat content and the fresh-weight-based concentrations of OCs, apart from total PCBs. On a fat-weight basis the concentration of coplanar PCBs was also higher in sprat than in herring. It is concluded that the Baltic salmon is provided with an adequate supply of thiamine, at least for growth, from its two main prey species, Baltic herring and sprat. Furthermore, sprat might have been the principal source of organochlorines, particularly coplanar PCBs and PCDFs, for salmon. The concentrations of these compounds were earlier found to have increased in salmon coincidently with the outbreak of the M74 syndrome. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved .

Physical and chemical characteristics of shallow embayments on the southern coast of Finland

Regular water-quality monitoring is yielding a great number of hydrographical and chemical data regarding the brackish Baltic Sea. However, present monitoring programmes often do not include shallow and sheltered near-shore areas, which are adjacent to human population and used for recreation purposes. We collected new near-shore water quality data from the southern coast of Finland that will allow the definition of the present state of these systems and may serve as reference data for possible future monitoring programmes. The data set comprises 45 small and shallow embayments with a mean surface area of 211 ha and a mean depth of 4.3 m. According to redundancy analysis (RDA), catchment land use explained 20.3% of the variance in the measured water chemistry. Agriculture had the strongest influence on the water quality of the study sites, capturing 13.1% of the variance. Nitrogen seemed to be strongly related to agriculture, whereas phosphorus was correlated with urban areas and industry. Higher than average nutrient concentrations regularly occurred at the mouths of large rivers, or close to human settlement, emphasising the significance of local sources to the nutrient concentrations of coastal waters. No increasing trend in nutrient or chlorophyll-a concentrations was observed from west to east in these shallow and sheltered nearshore areas. This contrasts with earlier results from pelagic samplings that report a marked influence of the River Neva and St. Petersburg on the nutrient status of the Gulf of Finland. Because these shallow embayments are strongly influenced by the local nutrient load, continued measures must be undertaken to reduce the nutrient load from land to prevent the continued deterioration and eutrophication of the nearshore, coastal waters.