Soft-bottom macrobenthic faunal associations and factors affecting species distributions in an Arctic glacial fjord (Kongsfjord,Spitsbergen)

The Kongsfjord (west Spitsbergen) hosts the most active glacier on the island. Therefore the glacial impact on the marine ecosystem is very pronounced and easily recognisable. The study examines the influence of the steep glacier-derived environmental gradients on dominant macrofaunal species distributions and faunal associations in the fjord. The macrobenthic fauna was sampled by van Veen grab at 30 stations situated throughout the fjord (at depths 38–380 m). Two major communities were recognised. An inner basin receives the outflows from three glaciers and is occupied by a Glacial Bay Community dominated by small, surface detritus-feeders, with Chone paucibranchiata and a set of thyasirid and nuculanid bivalves (Thyasira dunbari, Yoldiella solidula, Y. lenticula) as characteristic species. An outer basin of the fjord is characterised by a common set of dominant species, including Heteromastus filiformis, Maldane sarsi, Levinsenia gracilis, Lumbrineris sp. and Leitoscoloplos sp. Three associations may be distinguished within the Outer Basin Community. Association TRANS is of transitional character, with Nuculoma tenuis and Terebellides stroemi. Association CENTR is the most typical for the community. It is dominated by tube-dwelling Prionospio sp., Clymenura polaris, Galathowenia oculata and Spiochaetopterus typicus. Association ENTR contains shelf benthos elements, e.g. Ophiura robusta and Lepeta caeca. An opportunistic eurytopic Chaetozone group is present throughout the fjord and its density and dominance increase with proximity to the glaciers. Dominant species distribution is discussed in relation to environmental factors, of which sediment stability, inorganic particle concentration, sedimentation rate and amount of organic matter in sediments are considered to be most important in structuring the communities.     

Spitsbergen glacial bays macrobenthos – a comparative study

Macrobenthos was studied in seven glacial bays situated along the Spitsbergen coast between 77 and 79°N. The fauna was dominated by deposit-feeding or carnivorous polychaetes and bivalves. Only 4 of 118 species identified in the collected material occurred in all the west Spitsbergen localities examined (the polychaetes Chaetozone/Tharyx sp., Cossura longocirrata, Lumbrinereis fragilis s.l. (sensu lato), and the bivalve Thyasira flexuosa). Clustering of samples showed a difference between the faunas of east and west Spitsbergen; the latter formed two subgroups, localities open to Atlantic waters and those from inner fjord basins. The fauna in open basins was dominated by cosmopolitan species, whereas arctic elements shares were higher in inner basins and predominated in the fauna in Bettybukta (east Spitsbergen). This indicates arctic, relict character of the inner fjords sites. The biomass ranged from 6 to 310 g/m² and Shannon diversities from 0.49 to 2.54. Received: 16 July 1997 / Accepted: 9 February 1998     

Food resource partitioning among Arctic sublittoral lysianassoid amphipods in summer

Five species of lysianassoid amphipods (Anonyx nugax, Anonyx sarsi, Onisimus caricus, Onisimus edwardsii, Orchomenella minuta) co-occur in the shallow sublittoral of Kongsfjorden (Svalbard, Arctic), share similar functional attributes, and exploit a common food base. All species are known to be necrophagous; however, this study revealed through combination of gut-content analysis with the morphological characteristics of their mandibles and available information on feeding ecology, the complexity of their trophic strategies. Only mature individuals of A. nugax are true scavengers; immature individuals of this species feed on both animal and non-animal food. A. sarsi and O. caricus are scavengers and predators; the former prefers polychaetes, while the latter relies mostly on zooplankton. O. edwardsii is an omnivorous feeder, and the set of its primary food consists of carrion, crustaceans, and algae. O. minuta is a detrivorous–carnivorous species. These results indicate that niche overlap among these closely related species is reduced, not only by spatial segregation, but also by the exploitation of different components of food resources.     

Ultrastructure of nuchal organs in some marine polychaetes

Polychaetes normally possess one pair of nuchal organs at the posterior edge of the prostomium or peristomium. They have been regarded as chemosensory organs. The nuchal organs of four marine polychaete species with different habits were investigated by electron microscopy. Although the shapes of nuchal organs can vary greatly from simple ciliary bands (Scolelepis squamata, Spionidae) to retractile tongue-like, piston- or finger-shaped forms (Eteone longa, Anaitides mucosa, Phyllodocidae; Heteromastus filiformis, Capitellidae), the structural components, including the ciliated supporting cells, sensory cells, and nuchal epidermal cells, are essentially similar. The differences basically concern 1) the position of the sensory cells with relation to the ciliated supporting cells, 2) the location and structure of the nuchal nerve, and 3) the structure of the nuchal cuticle. The diverging nature of this modified cuticle is described and discussed in detail. Comparisons are made with the fine structure of nuchal organs of other polychaete species. Similarities of cellular components of nuchal organs are found not only in the four species studied here but also in all nuchal organs investigated so far. This is hypothesized to be due to the fact that the polychaete stem species already possessed nuchal organs with the respective cell types. Differences in the number and distribution of cellular components and in the overall shape of nuchal organs are thought to have evolved in correlation with the equipment of other cephalic appendages and with different habits and modes of nutrition.     

Invasion of a Reef-builder Polychaete: Direct and Indirect Impacts on the Native Benthic Community Structure

In this work, we evaluate the effect of the introduced reef-building polychaete Ficopomatus enigmaticus on the benthic community and on sediment characteristics of a southwestern Atlantic coastal lagoon. When reefs were experimentally added, density of the native crab Cyrtograpsus angulatus dramatically increased in a short time period. After reefs and crabs were experimentally transplanted as a unit, they decreased the density of the free-living soft-bottom polychaetes Heteromastus similis and Laeonereis acuta. Exclusion/inclusion caging experiments showed that Cyrtograpsus negatively affect the density of soft-bottom polychaetes (H. similis, L. acuta, Nephtys fluviatilis) and ostracodes. Our results showed that this effect is much higher in areas populated by reefs because of the increased density of crabs that find shelter under the reefs. Thus, reefs have a cascading effect on the native benthic community within the areas colonized by them. Analysis of crab stomach contents indicated that crabs feed on a wide variety of prey, including infaunal organisms, small gastropods and also algae. When reefs and crabs were experimentally added, the amount of bivalve shells on superficial sediments increased. Our results suggest that this bivalve shell accumulation and sediment composition are due to the reworking activity of Cyrtograpsus in the sediment where they dig burrows. The invasive habits of Ficopomatus may be favoring crabs to have a major effect on the integrity of the native community in the lagoon. Ficopomatus should be considered a bioengineer organism by creating and regulating refuge for other species, altering the interactions between preexistent species and also by changing the physical factors of the invaded environment.     

Chaetal arrangement in Orbiniidae (Annelida,Polychaeta) and its significance for systematics

The systematic position of Orbiniidae within Polychaeta is still uncertain. In order to provide additional comparative data, we investigated the chaetal arrangement in this family, which is considered valuable for polychaete systematics. Specimens of Scoloplos armiger, Orbinia latreillii, and Pettibonella multiuncinata were examined by SEM and serial sections analysed by computer aided 3D-reconstructions. The obtained data suggest that the chaetal arrangement of Orbiniidae resembles that of other sedentary polychaetes in only a few respects. Transverse rows are only present in the main, anterior part of the chaetal patches of thoracic neuropods. The position of the formative site indicates homology with the transverse rows of several sedentary polychaete taxa. The chaetal patches thus differ significantly from those known in Apistobranchidae. Independent rows with an own caudal formative site, which run along the caudoventral edge of the chaetal patches, resemble the neuropodial ventral longitudinal rows known in Spionidae and related taxa. The abdominal neuropodia of S. armiger and O. latreillii bear longitudinal rows of chaetae. These are reorientated during ontogenetic chaetiger transformation and become the transverse rows of the thoracic chaetal patches. 3D reconstruction of S. armiger revealed that the notopodial chaetal bundles are organized in rows as well. Notopodia and abdominal neuropodia bear deep reaching supportive chaetae. They are the first chaetae formed during neuropodial development and reside dorsally to the longitudinal row of capillary chaetae. Neither position nor structure indicates homology with the supportive chaetae of other sedentary polychaetes. Spionidae and related taxa are thus the only sedentary polychaetes, which specifically resemble Orbiniidae in certain aspects of their chaetal arrangement. Dedicated to Prof. Dr. Wilfried Westheide on the occasion of his 70th birthday.     

Megabenthic commmunities in the waters around Svalbard

 Composition and distribution of megabenthic communities around Svalbard were investigated in June/July 1991 with 20 Agassiz trawl and 5 bottom trawl hauls in depths between 100 and 2100 m. About 370 species, ranging from sponges to fish, were identified in the catches. Species numbers per station ranged from 21 to 86. Brittle stars, such as Ophiacantha bidentata, Ophiura sarsi and Ophiocten sericeum, were most important in terms of constancy and relative abundance in the catches. Other prominent faunal elements were eunephthyid alcyonarians, bivalves, shrimps, sea stars and fish (Gadidae, Zoarcidae, Cottidae). Multivariate analyses of the species and environmental data sets showed that the spatial distribution of the megabenthos was characterized by a pronounced depth zonation: abyssal, bathyal, off-shore shelf and fjordic communities were discriminated. However, a gradient in sediment properties, especially the organic carbon content, seemed to superimpose on the bathymetric pattern. Both main factors are interpreted as proxies of the average food availability, which is, hence, suggested to have the strongest influence in structuring megabenthic communities off Svalbard. Received: 28 April 1995/Accepted: 18 November 1995     

Benthic invertebrates as indicators of organic pollution in the Western Baltic Sea

The quantitative distribution of some important benthic invertebrates in a shallow inshore area of Kiel Bay (Western Baltic Sea) is described. This region is partly polluted by domestic sewage from the municipality of Kiel. Three groups of species are distinguished with reference to their densities and other population parameters in the different subareas: Progressive species of the 1st and 2nd order indicate a high and moderate to slight degree of pollution respectively by high population numbers. Regressive species are adverse indicators, absent or occurring in exceptionally low numbers in affected areas. In many cases the examination must be concentrated on sand bottom, because a series of species normally dwelling on aufwuchs build up dense populations in sand, if it is organically enriched. The polychaetes Capitella capitata, Nereis diversicolor and Polydora ligni are regarded as progressive species of the 1st order. The amphipods Corophium insidiosum and Gammarus salinus, the mussel Mytilus edulis, the polychaete Pygospio elegans, the snail Hydrobia ulvae, and some other invertebrates belong to the group of indicators for slight organic pollution. The main regressive species are the amphipod Bathyporeia sarsi and the mite Copidognathus fabriciusi.     

The functional response of copepodid stages to adult of Parabroteas sarsi (copepoda,calanoida)

P. sarsi is a carnivorous calanoid commonly found in South Andes lakes. Feeding experiments were carried out in order to analyze the functional response of P. sarsi (copepodid IV to adult) on different cladoceran prey. Predation rates increased with increasing prey density up to maximum (type II) in almost cases. The highest attack coefficients were obtained when P. sarsi adults were fed with the smaller prey (C. dubia juvenile and B. longirostris). The ingestion rates of copepodid IV and CV were smaller than for the adults. The ingested biomass as a proportion of predator biomass (B_e/B_p) showed an inversal relationship with the predator length. The maximum B_e/B_p ratio, in both sex of P. sarsi, was achieved with C. dubia adult, the intermediate-sized prey.     

Intertidal Benthic Invertebrates and Sediment Stability at the Mouth of Delaware Bay

From December 1970 to December 1972, the monthly species composition, density, species richness, and biomass of marine macroscopic invertebrates were quantitatively studied from a wave-protected, intertidal sand flat at the mouth of Delaware Bay. Considerable erosion, transportation, and deposition of sand occurred throughout the study period. The fauna was extremely flexible and resilient in its response to a gradient of considerable sediment mobility. This response was similar in scope to one recognized along the coast of California. Comparison of the local biota with other sand flats and beaches from Maine to South Carolina showed that (1). haustoriids were among the dominant species, (2). densities were roughly comparable, and (3). secondary species were similar. Based on the biological index value, three species contained 87.8% of the fauna from the Cape Henlopen tide flat. These species were the polychaete Scoloplos fragilis and the amphipod Neohaustorius biarticulatus, which were characteristic of sand bars, and the polychaete Heteromastus filiformis, which was more characteristic of troughs or depressions. Mean density varied considerably both monthly and annually with almost no cyclic repetition for any of the three species. There was evidence to indicate that specific habitat requirements of a few species can strongly affect the structure which emerges for a total fauna. Morphology, behavior, physiology, and reproductive strategy are aspects of biology which link dominant benthic species of intertidal sand beaches together.     

Spatial and inter-annual variability of the macrobenthic communities within a coastal lagoon (Óbidos lagoon) and its relationship with environmental parameters

The present work aims to analyse spatial and inter-annual variability in the benthic environment within the Óbidos lagoon, assessing the relationships between environmental characteristics and macrobenthic distribution patterns. Sediment samples were collected in February 2001 and 2002 for the study of macrofauna and biogeochemical parameters (sediment grain size, organic matter, organic carbon, chlorophyll a, and phaeopigments). Comparing 2001 to 2002, a general increase in the number of species, diversity and equitability indices was observed throughout the study area. Likewise, there was an increase of phytopigments and organic matter contents in the upper sediment layer. Based on the macrobenthic community patterns and environmental variables three main areas could be distinguished in both years: an outer area near the inlet mostly influenced by the sea, with very depressed number of species and abundance, and dominated by Saccocirrus papillocercus, Lekanesphaera levii, Microphthalmus similis and Nephtys cirrosa; an intermediate area located in the central part of the lagoon characterized by sandy sediment and low organic carbon, and colonized by a high diverse community with Hydrobia ulvae, Cerastoderma edule and Abra ovata as the most characteristic species; and the innermost area of the lagoon with muddy enriched sediments dominated by Heteromastus filiformis, oligochaetes, Scrobicularia plana, Cyathura carinata, Corophium acherusicum, phoronids, insect larvae and Corbula gibba. Deposit-feeders were dominant in the muddy sediments from the inner area, where suspension-feeders were also abundant. Carnivores were associated with clean sandy sediments from the inlet area and herbivores were more abundant within the central area.     

Benthic foraminifera contribution to fjord modern carbon pools: A seasonal study in Adventfjorden,Spitsbergen

The aim of this study was to determine the amount of organic and inorganic carbon in foraminifera specimens and to provide quantitative data on the contribution of foraminifera to the sedimentary carbon pool in Adventfjorden. The investigation was based on three calcareous species that occur commonly in Svalbard fjords: Cassidulina reniforme, Elphidium excavatum and Nonionellina labradorica. Our results show that the species investigated did not contribute substantially to the organic carbon pool in Adventfjorden, because they represented only 0.37% of the organic carbon in the sediment. However, foraminiferal biomass could have been underestimated as it did not include arenaceous or monothalamous taxa. Foraminiferal carbonate constituted up to 38% of the inorganic carbon in the sediment, which supports the assumption that in fjords where non‐calcifying organisms dominate the benthic fauna foraminifera are among the major producers of calcium carbonate and that they play crucial roles in the carbon burial process. The results presented in this study contribute to estimations of changes in foraminiferal carbon levels in contemporary environments and could be an important reference for palaeoceanographic studies.     

Food partitioning and spatial subsidy in shelter‐limited fishes inhabiting patchy reefs of Patagonia

The diets of the most conspicuous reef‐fish species from northern Patagonia, the carnivorous species Pseudopercis semifasciata, Acanthistius patachonicus, Pinguipes brasilianus and Sebastes oculatus were studied. Pinguipes brasilianus had the narrowest diet and most specialized feeding strategy, preying mostly on reef‐dwelling organisms such as sea urchins, limpets, bivalves, crabs and polychaetes. The diet of A. patachonicus was characterized by the presence of reef and soft‐bottom benthic organisms, mainly polychaetes, crabs and fishes. Pseudopercis semifasciata showed the broadest spectrum of prey items, preying upon reef, soft‐bottom and transient organism (mainly fishes, cephalopods and crabs). All S. oculatus guts were empty, but stable‐isotope analyses suggested that this species consumed small fishes and crabs. In general, P. brasilianus depended on local prey populations and ate different reef‐dwelling prey than the other species. Pseudopercis semifasciata, A. patachonicus and probably S. oculatus, however, had overlapping trophic niches and consumed resources from adjacent environments. The latter probably reduces the importance of food as a limiting resource for these reef‐fish populations, facilitating their coexistence in spite of their high trophic overlap.     

近岸典型生态系统大型底栖动物的次级生产力——以瓯江口、洞头列岛为例

为更好了解和估算河口及岛屿生态系统大型底栖动物次级生产力的情况,以近岸两个典型生态系统河口-瓯江口、岛屿-洞头列岛为例,于2015年4月和10月在该海域进行大型底栖动物调查,采用3种Brey经验模型对大型底栖动物次级生产力进行估算,并分析次级生产力与环境因子的关系。结果表明:(1)以去灰干重(ash-free dry weight,AFDW)计,Brey经验公式估算瓯江口和洞头列岛海域年均次级生产力分别为0.48 g(AFDW)m~(-2)a~(-1)和0.70 g(AFDW)m~(-2)a~(-1),Brey模型估算瓯江口和洞头列岛海域年均次级生产力分别为0.51 g(AFDW)m~(-2)a~(-1)和1.55 g(AFDW)m~(-2)a~(-1),Brey模型估算瓯江口和洞头列岛海域年均次级生产力分别为0.25 g(AFDW)m~(-2)a~(-1)和0.99 g(AFDW)m~(-2)a~(-1)。(2)3种经验模型反映大型底栖动物年均次级生产力空间分布趋势一致:瓯江口海域有1高值区,位于瓯江口南部;洞头列岛海域有2高值区,分别位于洞头本岛东北部的三盘岛与花岗岛之间和东黄岛东南部的岛屿之间。(3)瓯江口海域大型底栖动物年均次级生产力主要贡献种为双鳃内卷齿蚕Aglaophamus dibranchis、长吻沙蚕Glycera chirori、异蚓虫Heteromastus filiforms、焦河篮蛤Potamocorbula ustulata、薄云母蛤Yoldia similis、圆筒原盒螺Eocylichna braunsi,它们对次级生产力的贡献率超54.2%;洞头列岛海域大型底栖动物年均次级生产力主要贡献种为双鳃内卷齿蚕、异蚓虫、薄云母蛤、绒毛细足蟹Raphidopus ciliatus、隆线强蟹Eucrate crenata、脑纽虫Cerebratulina sp.、红狼牙鰕虎鱼Odontamblyopus rubicundus,它们对次级生产力的贡献率超57.1%。(4)次级生产力与环境因子的相关性分析显示化学需氧量、悬浮物和表层沉积物中值粒径是影响瓯江口海域大型底栖动物年均次级生产力的重要环境因子,而环境因子与洞头列岛海域大型底栖动物年均次级生产力相关关系不显著。(5)瓯江口海域Brey经验公式与Brey模型估算结果基本一致,洞头列岛海域Brey经验公式与Brey模型估算结果基本一致。     

Problems in polychaete systematics

Some of the intriguing issues in current polychaete systematics are reviewed. (1) The root of the `polychaete' tree. Currently there are two major hypotheses concerning the root position among polychaetes. One is based on rooting cladograms with outgroups such as Mollusca and result in simple-bodied taxa such as Opheliidae and Questidae forming a basal annelid grade along with Clitellata. Other hypotheses do not use outgroup rooting but involve scenarios on the evolution of the group and would place taxa in Aciculata as basal annelids, thus making Aciculata and Phyllodocida paraphyletic. Molecular sequence data has been of little help in resolving this issue thus far, largely due to limited taxon sampling. (2) Paraphyly. Owing, in part, to a tradition involving the emphasis on differences among taxa, and the application of Linnean ranks (e.g., family), paraphyly is undoubtedly a widespread phenomenon in polychaete systematics. An example of this has been proposed already for Spionidae. If the tree topology and rooting used by Blake & Arnofsky (1999) is correct, Spionidae is made paraphyletic by the recognition of the following four family-ranked taxa; Trochochaetidae, Poecilochaetidae, Longosomatidae and Uncispionidae. Another possible example is seen with Cirratulidae. A preliminary cladistic analysis shows that it is entirely possible that seven other taxa recognised as families may be nested within Cirratulidae. These include Acrocirridae, Ctenodrilidae, Fauveliopsidae, Flabelligeridae, Flotidae, Poeobiidae and Sternaspidae. (3) Problematic taxa. Apart from the problems exposed by the analysis of Cirratuliformia, the position of some of these groups, such as Aberranta, Alciopidae, Hesionides,Lopadorhynchidae, Microphthalmus,Nerillidae, Spinther,Tomopteridae and Sabellariidae, is discussed.     

Broad-scale effects of marine salmonid aquaculture on macrobenthos and the sediment environment in southeastern Tasmania

A comparison of sediments and associated macrobenthos at sites sampled within 20 fish farm leases distributed across southeastern Tasmania indicated major natural changes along a regional cline. Introduced taxa were strongly represented in the fauna, comprising 45% of total macrofaunal biomass. Large differences were evident between sites affected by different levels of organic farm waste. Sites located adjacent (< 10 m) to farm cages possessed significantly depressed sediment redox levels, a dominance of capitellid and dorvilleid polychaetes, and low macrofaunal species richness. Subtle impacts extended across farm lease areas in the form of depressed redox potential at 40 mm depth and changes to the macrobenthic community, including a prevalence of the dogwhelk Nassarius nigellus and a paucity of the heart urchin Brissus sp. and the maldanid polychaetes Asychis sp. and Rhodine sp. Minor farm effects were also evident at sites sampled 35 m outside farm lease boundaries, most notably as elevated population numbers of the polychaete Terrebellides sp., bivalve Mysella donaciformis and heart urchin Echinocardium cordatum. Amongst the univariate metrics examined, redox potential at 40 mm depth and the ratio of bivalves to total molluscs provided the most sensitive indicators of farm impacts, with the latter metric relatively insensitive to spatial variation between locations within the region studied.     

Benthic Invertebrates in Delaware Bay: Animal-Sediment Associations of the Dominant Species

The purpose of this study was to determine the composition of the benthic fauna near the mouth of Delaware Bay. One hundred and five species were collected and identified from 277 grab samples. A sediment sample was also collected at each of the stations. Faunal density was low with the number of individuals rarely exceeding 10/0.1 m². Species were ranked according to number of individuals; the nine top species comprised 83.4% of the fauna. The top three species, Tellina agilis, Gemma gemma, and Nucula proxima, comprised 65.2% of all the individuals collected. A high percentage of the species (41.9%) occurred in two samples or less. The six most frequently collected species were compared with six sediment classes based on weight percentage of siltclay. Protohaustorius wigleyi and Trichophoxus epistomus were found mainly in less than 10% silt-clay. Tellina agilis and Ampelisca verrilli were transitional between the pure sand and mud facies. Nucula proxima and Heteromastus filiformis were members of a high silt-clay facies (<50% silt-clay). Diversity values were significantly greater (.05) in the low silt-clay sediments (0–25% silt-clay) than in the high silt-clay sediments (> 25% silt-clay). The relative dominance (redundancy) was not significantly different in any of the sediment types.     

Pathologies of non‐marine bivalve shells from the Late Triassic of Poland

Gorzelak, P., Nied?wiedzki, G. & Skawina, A. 2010: Pathologies of non‐marine bivalve shells from the Late Triassic of Poland. Lethaia, Vol. 43, pp. 285–289. Shells of Late Triassic non‐marine bivalves from Lisowice (Lipie ?l?skie clay pit, southern Poland), which co‐occur with remains of several vertebrate taxa (mammal‐like reptiles, carnivorous dinosaurs, pterosaurs, temnospondyl amphibians, hybodont sharks, dipnoan and ganoid fish), bear evidence of pathologies. Distribution, dimension and shape of some of these injuries (radiate tooth marks) closely match the dental morphology of lungfish (here probably represented by the genus Ceratodus). Thus, we interpret these pathologies as evidence of unsuccessful predatory attack on bivalves by this fish. This interpretation is also consistent with modern examples of such behaviour among lungfish. The feasibility that other culprits caused other pathologies (shell scarring and wedges) on the bivalves analysed is also discussed. Discovery of these traces constitutes important evidence of predator–prey interaction, which provides ‘fingerprints’ of trophic structure within this Late Triassic freshwater ecosystem. □Freshwater bivalves, lungfish, pathologies, predation, Triassic.     

Heavy Metal Contents in Tissues of Dominant Species of the Benthos and in Bottom Sediments of Zolotoi Rog Bay, Sea of Japan

Data on heavy metal contents in polychaetes and free-living nematodes inhabiting the bottom sediments of Zolotoi Rog Bay near the port of Vladivostok are reported. Chronically high contents of heavy metals (Fe, Cu, Zn, and Cd) were found in the bottom sediments and in the infauna. The levels of some toxic elements in tissues of the polychaete Dorvillea (Schistomeringos) japonica inhabiting polluted sediments of Zolotoi Rog Bay were higher than in worms of this species from relatively clean areas of the Sea of Japan. Similar high concentrations of Fe were found in the polychaete Capitella capitata and the nematode Oncholaimium ramosum. The highest concentrations of Fe, Zn, Cu, and Cd were found in tissues of the free-living nematode O. ramosum. Chronic heavy pollution of the bottom sediments leads to a decrease in the biodiversity of the infauna and to specific metal-tolerant communities.Original Russian Text Copyright © 2005 by Biologiya Morya, Davydkova, Fadeeva, Kovekovdova, Fadeev.     

Preservation effects on wet weight, dry weight, and ash-free dry weight biomass estimates of four common estuarine macro-invertebrates: no difference between ethanol and formalin

Two preservative treatments traditionally used in aquatic sciences, formalin (4%) and ethanol (70%), were compared for their effects on biomass estimations. The effects of both preservatives on wet weight, dry weight, and ash-free dry weight were determined for samples preserved for 10, 21, and 90 days. The effects were studied in four different macrofauna species commonly found in German estuaries: Heteromastus filiformis (Capitellidae, Polychaeta), Hediste diversicolor (Nereididae, Polychaeta), Corophium sp. (Amphipoda, Crustaceae), and Gammarus spp. (Amphipoda, Crustacea). The biomass estimates of preserved samples were compared with those of unpreserved samples. In all four species the loss in wet weight, dry weight, and ash-free dry weight was most pronounced within the first 10 days, and an additional weight loss was recorded between days 10 and 21. However, there was no further loss in weight for samples kept for as long as 90 days in the preservatives. In general, crustaceans exhibited higher weight loss than polychaetes, and smaller species (H. filiformis and Corophium sp.) showed higher weight loss and a higher variability than larger species. As our main result, significant differences between the two preservative treatments did never occur. Our results contradict some earlier investigations on this matter where formalin has been reported to be superior to alcoholic preservatives because weight loss was less pronounced than in ethanol. Factors affecting biomass estimates are discussed and we conclude that, for the macrofauna groups tested, the use of the toxic formalin solution is not justified when the major intent is biomass estimation.