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Fine organic particles in a sandy beach system (Puck Bay, Baltic Sea)

Kotwicki L., Węsławski J. M., Szałtynis A., Stasiak A., Kupiec A.

Oceanologia

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2005

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No. 47 (2)

165-180

EN

A total of over 550 samples of particulate organic matter (POM) were obtained from swash and groundwater samples taken on a monthly basis from seven localities on the sandy shores of Puck Bay in 2002 and 2003. Sandy sediment cores from the swash zone were collected to assess the amount of POM in the pore waters. The mean annual concentrations of POM varied between localities from 20 to 500 mg in groundwater and from 6 to 200 mg dm-3 in swash water. The carbon/nitrogen (C/N) ratio in suspended matter was always higher in groundwater (annual mean 12) than in swash water (annual mean 7). The C/N ratio indicates a local, algal origin of POM in the shallow coastal zone.

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Deposition of large organic particles (macrodetritus) in a sandy beach system (Puck Bay, Baltic Sea)

Kotwicki L., Węsławski J. M., Raczyńska A., Kupiec A.

Oceanologia

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2005

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No. 47 (2)

181-199

EN

The aim of this study was to evaluate the amount of organic macrodetritus deposited on the sandy shores of the southern Baltic, and to determine the type of washout material and their chemical composition (carbon and nitrogen). Over 900 samples of macrodetritus (particles retained on a 0.5 mm sieve) were collected from seven sampling locations along a 120 km stretch of coastline in Poland at monthly intervals in 2002. Analysis of the C and N content of several categories of detritus supplied information about seasonal changes in and the ageing of algal debris, and indicated that the amount of carrion is constant; the latter is apparently always metabolised very rapidly. The annual deposition of macroalgal detritus on this coast was estimated at 15 000 tonnes fresh weight, that is around 75% of the primary production of filamentous macroalgae in Puck Bay. In comparison with the amounts of kelp deposited on sandy beaches in South Africa (Griffiths & Stenton-Dozey 1981), the massive seaweed washouts on Mediterranean beaches (Morand & Briand 1996), or the deposition of algal mats in the northern Baltic (Norkko & Bonsdorff 1996a), the quantities of macrodetritus on the shore in the study area are average, even allowing for the fact that the Baltic Sea is highly eutrophic (HELCOM 2005).

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Attenuation of wave-induced groundwater pressure in shallow water. Part 1

Massel S. R., Przyborska A., Przyborski M.

Oceanologia

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2004

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No. 46 (3)

383-404

EN

A coastal aquifer has a dynamic seaward boundary at the beach face where physical and ecological processes are influenced by oceanic water level fluctuations. Many basic groundwater concepts and the role of the impact of groundwater seepage on beach ecosystems are still poorly understood. Studies are needed to improve our understanding of the relationships between surface and subsurface flow processes on beaches. This is particularly helpful in clarifying the interaction of the physical processes, biodiversity and productivity of sandy beaches, sediment transport and coastal structure stability and modern beach nourishment techniques. As the estimation of infiltration into beach sand is very difficult to carry out under real sea conditions, a control led large-scale laboratory experiment was carried out in the Large Wave Channel in Hannover (Germany) as part of a project supported by the European Community (contract HPRI-CT-2001-00157). First part of the paper describes the technology applied in the experiment and reports some preliminary results.

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Predrying of stranded wrack material as an aspect of the litterbag techniques in the sandy beach studies

Jędrzejczak M. F.

Oceanological and Hydrobiological Studies

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2003

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Vol. 32, No. 1

59-74

EN

Methodological aspects of the arrangement of stranded wrack for the degradation rates within the litterbags were tested in a simple field experiment on temperate, fine/medium quartz sediment, sandy beach in Poland at the end of the Hel Peninsula (54°36’N, 18°49’E). Litterbags of the mesh size of 0.5 mm were used to construe and assess the role of the pre-drying of wrack before its placement into the bags. The field station was established on the backshore, 15 m in width seaward from the crest of a dune. Three methods of predrying were done: (1) air drying, (2) oven drying, (3) freeze drying, as well as (4) non-dried fresh material was used as reference. The stranded seagrass wrack (Zostera marina L.), obtained directly from the beach, and then prepared in accordance with the procedures described above, was used as the study material. Four trials were run with five repetitions of litterbags 7 cm long ´ 7 cm wide made from nylon mesh with 0.5 mm aperture widths. After exposition, bags were retrieved 5, 10, 50, 100, 150, 200 and 250 days post-placement. In the laboratory, samples of remaining material were dried by the same method as earlier, respectively, and then weighed, and analysed using a CHNS Analyser. It was shown that, under similar conditions of sediment composition, salinity and wave inundation, the method of predrying had little influence on the long-term process of decay. In the case of non-dried replicates, degradation rapidly proceeded in the initial stages and then stabilised to be linear, whereas, in dried samples it was done so linearly throughout the study period with only little differences. Such differences observed in the early part of the experiment were most likely the result of differences in material structure and the initial chemical composition of the plant material caused by a predrying-incurred disturbance in the chemical structure. Nevertheless, short-term environmentally driven sampling strategies fail to obtain conclusive results about degradation estimates of stranded wrack and should be avoided at least with the use of dried material.

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Microphytobenthic primary production along a non-tidal sandy beach gradient : an annual study from the Baltic Sea

Urban-Malinga B., Wiktor J.

Oceanologia

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2003

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No. 45 (4)

705-720

EN

The microphytobenthic primary production and chlorophyll a content were studied over the annual cycle (May 1998 - May 1999) on a non-tidal Baltic sandy beach at three stations along the beach gradient: littoral, waterline and splash zone. The chlorophyll a concentrations varied between 0.88 and 12.18 žg cm-3. Net and gross primary production rates respectively lay within the ranges 0.1-31.4 mgC m-2 h-1 and 0.2-41.8 mgC m-2 h-1. The highest values of both Chl a content and primary production were noted at the littoral station, the lowest ones at the waterline. The mean annual P/B ratio was highest at the waterline. The differences in Chl a content between stations were statistically significant and may be related to water dynamics, resuspension and water content. Production rates were highly variable on monthly time scales, and the highest results at all the study locations were noted in July. The gross photosynthetic rates were significantly correlated with water temperature.

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Seasonal changes of itersititial community respiration in a Baltic sandy beach

Urban-Malinga B., Opaliński K. W.

Oceanological Studies

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2002

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Vol. 31, No. 3-4

57-70

EN

Interstitial community respiration in a Baltic sandy beach on the Gulf of Gdańsk was investigated in terms of sediment oxygen consumption over a seasonal cycle. The study was carried out at four locations on the beach slope (littoral, waterline, splashzone and middle beach). Oxygen uptake changes over time were not statistically significant and no correlation was found between sediment respiration and water temperature. It seems that food supply to the sandy beach system is the predominant factor determining the interstitial community metabolism. The lowest values of oxygen consumption (9-33 cm3 O2 m-2 h-1) were noted in the middle beach station; the highest results (up to 212 cm3 O2 m-2 h-1) were related to the littoral site. Organic matter concentration in the sediment ranged between 0.09 and 0.9% dwt.

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Stranded Zostera marina L. vs wrack fauna community interactions on a Baltic sandy beach (Hel, Poland) : a short-term pilot study. Part I. Driftline effects of fragmented detritivory, leaching and decay rates

Jędrzejczak M. F.

Oceanologia

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2002

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No. 44 (2)

273-286

EN

The effects of the beach community structure of macro- and meiofauna on the process of beach wrack decay were investigated by means of a simple field colonisation experiment in a temperate, fine quartz sediment, sandy beach at the end of the Hel Peninsula in Poland. 1260 replicate litterbags of three mesh sizes (12 mm, 0.5 mm, 48 žm) containing fresh wrack were used to assess the role of faunal and non-faunal components in the breakdown of stranded Zostera marina. Wrack breakdown was determined during a three-year field study. This paper presents the first part of the results of this field experiment, which refer to the effects of fragmentation detritivory, leaching and decay rates. Material was lost from the bags at a rapid rate, with only 22-32% of the original dry mass remaining after 27 days in the field. This degradation was not directly related to the faunal succession of the eelgrass tissue, which proceeded in two distinct phases throughout the study period. Exclusion of macrofauna from the wrack by the use of finer-mesh litterbags (< 1 mm) had no appreciable effect on the rate of dry matter loss. Microbial decay, and abiotic leaching and fragmentation are probably the major causes of seagrass weight loss from the litterbags.

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Stranded Zostera marina L. vs wrack fauna community interactions on a Baltic sandy beach (Hel, Poland) : a short-term pilot study. Part II. Driftline effects of succession changes and colonisation of beach fauna

Jędrzejczak M. F.

Oceanologia

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2002

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No. 44 (3)

367-387

EN

This paper evaluates the second part of a three-year field study to investigate the effects of the beach macro- and meiofauna community structure on the decay of stranded wrack on Hel Beach (see Jedrzejczak 2002), focusing on successional changes and the colonisation of wrack by beach fauna. The investigation enabled the associated faunal assemblages to be characterised. Zostera marina tissue was colonised by the supralittoral fauna in two distinct phases. The macrofauna, including the talitrid amphipod Talitrus saltator, adult Diptera and Coleoptera, colonised the wrack within a day, with maximum numbers being recorded after 3 days. Thereafter, their numbers in the samples declined and the meiofauna, consisting of nematodes, oligochaetes, turbellarians and dipteran larvae, became increasingly abundant. After 18 days, the wrack surface was dominated by meiofauna. This faunal succession was not directly related to the degradation of the seagrass tissue, which proceeded linearly throughout the study period. Exclusion of macrofauna from the wrack by the use of < 1 mm mesh litterbags had no appreciable effect on the rate of dry matter loss. Therefore, the major macrofaunal wrack consumers, including T. saltator and Coleoptera, did not affect the rate of seagrass disintegration. The effect of meiofaunal nematodes, oligochaetes, gastrotrichs and turbellarians on wrack breakdown could not be accurately determined. However, the development of the meiofaunal community suggested that changes in the fauna community were linked more closely to successional changes in the chemistry and/or microflora of the beach wrack than to its physical breakdown.

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Spatio-temporal decay 'hot spots' of stranded wrack in a Baltic sandy coastal system. Part I. Comparative study of the pattern : 1 type of wrack vs 3 beach sites

Jędrzejczak M. F.

Oceanologia

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2002

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No. 44 (4)

491-512

EN

The significance of distance along the beach-dune transect and different moisture conditions as regards the decay of Zostera marina leaf litter was investigated in simple field experiments in three temperate, medium- to fine-quartz-sediment, sandy beaches of the Gulf of Gdansk in Poland. 1800 replicate litterbags of freshly stranded Zostera marina leaves were placed in beach sediments at different strata and levels on each of the beaches. The litterbags were sampled after 5, 10, 50, 100 and 150 days in the field and the remaining material was then dried and weighed. Under similar conditions of sediment composition, salinity and wave inundation, ANOVA tests revealed significant differences in breakdown through time and site. Thus there were some differences in the decay process between the low and high beach. In the former, degradation proceeded rapidly in the initial stages and then stabilised, while in the latter it remained linear throughout the study period. Matter loss in each stratum was also seasonally dependent. This may, however, be more closely linked to successional changes in the chemistry and/or microflora of the beach wrack than to its physical breakdown. Differences between organic matter degradation in the high and low beaches may be explained by differences in the moisture regime and nutrient status, and not by differences in the decay processes themselves. Therefore, two decay centres were found in the beach-dune system: the low beach together with the strandline (wrack consumption 12-21% day-1 in the warm season, and 4-10% day-1 in the cold season) and the dune (active consumption 2-6% day-1 in the warm season only).

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Interstitial community oxygen consumption in a Baltic sandy beach: horizontal zonation

Urban-Malinga B., Opaliński K. W.

Oceanologia

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2001

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No. 43 (4)

455-468

EN

The oxygen consumption of a sandy beach interstitial community was determined on four occasions (January, May, August, October) on the Gulf of Gdansk (southern Baltic Sea). The study was carried out at four locations on the beach slope (littoral, waterline, splash zone and middle beach). Oxygen consumption varied from 158-159 cm3 O2 m-2 h-1 at the underwater site and waterline to 20-36 cm3 O2 m-2 h-1 in the middle beach. According to these data, interstitial organisms are able to utilize from 206 to 1641 mg of organic carbon per square metre per day. In general, metabolic activity decreased gradually from the waterline towards the middle beach, and a significant correlation was found between oxygen consumption and sediment water content. Changes in oxygen consumption on the beach slope were statistically significant.

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Bacteriological investigations of the sandy beach ecosystem in Sopot

Olańczuk-Neyman K., Jankowska K.

Oceanologia

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1998

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No. 40 (2)

137-151

EN

The paper presents the results of bacteriological investigations relating to the coastal seawater and sandy sediments along the beach in Sopot in an area between the mouths of two streams, Grodowy Potok and Kamienny Potok. The sandy sediments investigated at four sites along a transect perpendicular to the shore contained variable numbers of saprophytic bacteria. In areas close to the littoral zone large numbers of allochthonous bacteria were found. With increasing distance from the waterline their domination declines to the advantage of autochthonous bacteria, an indication of the decreasing influence of anthropogenic pollution.