Sewage pollution and extinction risk: an endangered limpet as a bioindicator?

The mollusc Patella ferruginea, endemic to the Mediterranean, is the most endangered marine species on the list of the European Council Directive 92/43/EEC and it is under serious risk of extinction. In spite of the low abundances and restricted distribution of this limpet, important populations have been found in the harbour of Ceuta, north Africa. The main objective of the present study was to characterise, for the first time, the effects of sewage pollution on P. ferruginea and related limpet species, and to evaluate the potential value of these limpet assemblages as bioindicators, using univariate and multivariate analyses. Physicochemical parameters and limpets were sampled in nine stations located at 0, 1, 2, 4, 8, 16, 32, 64 and 128 m away from the discharge point of a sewage effluent in Ceuta harbour. The stations closer to the outfall (0, 1, 2, 4 and 8) were characterised by higher values of turbidity, phosphate and ammonia in the water column, and organic matter, faecal coliforms and faecal Streptococci in sediments. A total of six limpet species were found and studied (Patella ferruginea, P. caerulea, P. nigra, P. rustica, P. ulyssiponensis and Siphonaria pectinata); the number of limpet species increased with increasing distance from the outfall, while diversity and evenness reached the highest values at intermediate sites. Siphonaria pectinata and P. caerulea were the most resistant and abundant species, while P. ferruginea was the most sensitive species to sewage pollution, only found at stations from 32 to 128 m. The distribution of this endangered limpet seems mainly affected by the pollution gradient, and not by the competition with the remaining limpets. The results of this study should be taken into account in future programmes of management and conservation of P. ferruginea.     

Invertebrate Community Associated with the Macroalga Halimeda kanaloana Meadow in Maui,Hawaii

An expansive meadow of the native macroalga Halimeda kanaloana has been found in west Maui, Hawaii. This study examined the invertebrate community associated with the H. kanaloana meadow. Analyses of samples collected by SCUBA divers found that the meadow supports a diverse and unique benthic community. The meadow provides a suitable habitat for a variety of epibenthic and epifaunal invertebrates in the otherwise homogeneous sandy habitat. Infaunal polychaete abundances, species richness and Shannon‐Wiener diversity index were also higher inside the meadow. Abundances of epibenthic organisms, and dissimilarities of the polychaete assemblage, inside and outside the meadow were greater at deeper stations. This might be due to an effect of the Halimeda density rather than depth, suggesting that the macroalgal density might play an important role in shaping the benthic community. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Polychaete distribution on the southwestern Atlantic continental shelf

Diversity and distribution of polychaetes on the southeastern Brazilian Shelf (SBS) adjacent to the city of Santos were studied. The study area is situated in the vicinity of Santos Bay with its estuarine complex and other small rivers along the coast. A total of 16,274 specimens belonging to 214 polychaete species were found at 21 sampling stations during two different periods. Two communities occur along the shelf and were related firstly to sediment characteristics. Prionospio dayi (Spionidae) was dominant in the inner shelf community that was characterized by well-sorted, very fine sand. The outer shelf community was found in muddy sediments with high organic matter content and was dominated by subsurface deposit feeders, like Petersenaspis capillata (Sternaspidae) and Leitoscoloplos kerguelensis (Orbiniidae), and by large carnivores such as Aglaophamus sp. (Nephtyidae) and Sigambra sp. (Pilargidae). A transition zone of mixed sediments presenting high diversity and richness was found between these communities. The characteristics of bottom water and food quality in the sediment were important to divide the inner shelf into two sub-areas. Nearshore sampling stations (A group) were more influenced by freshwater input, mainly during summer. This influence is not conspicuous at stations close to 30?m depth (B group). However the effect of South Atlantic Central Water mass (SACW) intrusion on the benthic system was observed on the inner shelf – B group during the summer. The summer intrusion of SACW onto the inner shelf may explain the higher quality of organic matter that resulted in an increase in polychaete abundance and richness.     

Do Rapoport's rule,the mid‐domain effect or the source–sink hypotheses predict bathymetric patterns of polychaete richness on the Pacific coast of South America?

Aim We evaluated the bathymetric gradient of benthic polychaete species richness from the Chilean coast, as well as its possible underlying causes. We tested three possible hypotheses to explain the richness gradient: (1) Rapoport's effect; (2) the mid‐domain effect (MDE); and (c) the source–sink hypothesis. Location South‐eastern Pacific coast of Chile. Methods The bathymetric gradient in richness was evaluated using the reported ranges of bathymetric distribution of 498 polychaete species, from the intertidal to abyssal zone (c. 4700 m). Rapoport's effect was evaluated by examining the relationship between bathymetric mid‐point and bathymetric range extent, and species richness and depth. The MDE was tested using the Monte Carlo simulation program. The source–sink hypothesis was tested through nestedness analysis. Results Species richness shows significant exponential decay across the bathymetric gradient. The pattern is characterized by a high presence of short‐ranged species on the continental shelf area; while only a few species reach abyssal depths, and they tend to show extremely wide bathymetric ranges. Our simulation analyses showed that, in general, the pattern is robust to sampling artefacts. This pattern cannot be reproduced by the MDE, which predicts a parabolic richness gradient. Rather, results agree with the predictions of Rapoport's effect. Additionally, the data set is significantly nested at species, genus and family levels, supporting the source–sink hypothesis. Main conclusions The sharp exponential decay in benthic polychaete richness across the bathymetric gradient supports the general idea that abyssal environments should harbour fewer species than shallower zones. This pattern may be the result of colonization–extinction dynamics, characterized by abyssal assemblages acting as ‘sinks’ maintained mainly by shallower ‘sources’. The source–sink hypothesis provides a conceptual and methodological framework that may shed light on the search for general patterns of diversity across large spatial scales.     

Polychaete community structure of the northwestern coast of Mexico: patterns of abundance and distribution

In August 1998, 72 benthic stations were sampled off the northwestern coast of Mexico. A baseline survey of the polychaete macrofauna was carried out for the southernmost portion of the Southern California Bight (SCB) region. Spatial patterns of polychaete assemblages were characterized to determine evidence of environmental impact from point sources of wastewater discharge near the study area, and to define a standard against which to detect future change. A total of 4231 polychaetous annelids representing 38 families and 210 species were identified, which constituted 53% of the total macrofauna. Families with highest species richness were Spionidae (18 spp.), Onuphidae (15 spp.), and Terebellidae (14 spp.). Species with greatest abundances were Spiophanes duplex (490 ind.), Spiophanes fimbriata (330 ind.), Lanassa sp. D (209 ind.), Pectinaria californiensis (138 ind.), and Euclymeninae sp. A (124 ind.). Based on polychaete assemblages, communities for the southernmost SCB were found to be composed primarily of non-opportunistic species, and no numerically dominant species were found. High values of polychaete diversity (H) indicated the majority of the area of study could be considered an undisturbed environment. Principal Components Analysis (PCA) applied to environmental and faunistic parameters indicated depth, organic carbon, and sediment grain size as the main influences determining the polychaete faunal communities.     

象山港大型底栖动物生物多样性现状

2006年7月至2008年8月对象山港13个站位进行了8个航次的大型底栖动物采样调查.研究了该海域大型底栖动物群落的优势种组成, 大型底栖动物的丰度、生物量、次级生产力和P/B值,并采用物种丰富度指数、物种均匀度指数和物种多样性指数分析大型底栖动物物种的多样性.调查共获得大型底栖动物123种,其中软体动物48种,甲壳类33种,鱼类和环节动物多毛类各12种,棘皮动物8种,还包括一些腔肠动物、线虫等.群落中优势种较为集中,且优势度指数较高.该海域大型底栖生物年次级生产力平均值为16.70 ·m^-2·a^-1,平均P/B值为0.60.对物种丰富度指数(d)、均匀度指数( J )、辛普森多样性指数(D)和香农多样性指数(H)进行双因素方差分析表明,不同站位之间4种指数的差异均高度显著(P<0.01),周年之间4种指数的差异除均匀度指数不显著外(P>0.05),均高度显著(P<0.01).     

Distribution and diversity of polychaetes collected by trawling in Admiralty Bay: an Antarctic glacial fiord

The aim of the study is to determine patterns of distribution, species richness and diversity of polychaetes collected by trawling in Admiralty Bay. Forty-seven species of polychaetes were found in 75 samples collected in 1988 along a depth range from 15 to 500 m. Four polychaete assemblages were distinguished. The most diverse and peculiar assemblage was found in the deepest sublittoral of the central basin from ca. 300–500 m with main constant species Laetmonice producta, Sternaspis sp. and Thelepus cincinnatus. Shallow water assemblages had low diversity and species richness. The most common and eurytopic epifaunal polychaetes were Aglaophamus trissophyllus, Barrukia cristata, Harmothoe spp., Flabelligera mundata and Perkinsiana littoralis. The low species richness in shallow waters of Admiralty Bay is probably associated with depth, influence of glacial streams and suspended matter inflow which is particularly distinct in the shallow water fiord areas.     

Effect of urban and industrial wastes on species diversity of the diatom community in a tropical river,Malaysia

Monthly species diversity and other components of diversity of diatom samples collected over a period of one year at eight stations in the Linggi River Basin, Malaysia were analysed. Species diversity ranged between 0.52–3.62 bits individua^–1. Among the four stations located in the Linggi River (sensu stricto), highest diversity values were recorded at a station polluted by rubber effluent, followed by the stations unpolluted from point sources. Lowest diversity was recorded at a station polluted with urban sewage. At Kundor River, highest diversity was recorded at stations located downstream of rubber and palm oil waste discharges. On the whole, diversity values at unpolluted stations were always lower than at mildly polluted stations. Severe organic loadings caused low diversity by reducing the number of species (species richness) but did not increase the evenness (equitability) as expected when compared with unpolluted or mildly polluted stations. The changes in species diversity can be related to changes in diatom community structure and thereby changes in water quality, but cannot be used as an index of water quality.     

福建漳江口红树林和盐沼湿地的多毛类动物群落

为了比较漳江口4种植物生境之间多毛类动物群落的差异性,2010年对漳江口潮间带秋茄、桐花树、白骨壤和互花米草4种植物生境的多毛类动物进行4个季度的定量取样.共获得15种多毛类动物,4个季度在4种植物生境中均出现三角洲双须虫、溪沙蚕、拟突齿沙蚕、凿贝才女虫、小头虫和加州中蚓虫.多毛类动物栖息密度、生物量、丰度指数、均匀度指数和多样性指数的季节变化不明显;但4种植物生境之间多毛类动物栖息密度、生物量、丰度指数、均匀度指数和多样性指数有显著差异,且互花米草生境与3种红树林生境之间多毛类动物优势种不同.Pearson相关分析表明,漳江口红树林和盐沼湿地除了多毛类物种数与泥温显著相关外,多毛类动物栖息密度、生物量、丰度指数、均匀度指数和多样性指数均与泥温、盐度、总有机碳、总氮无显著相关关系,其原因是漳江口4种植物生境多毛类动物常见种小头虫、加州中蚓虫和溪沙蚕均是广温、广盐及耐高有机质含量的种类.     

Distribution and diversity of the Syllidae (Annelida: Polychaeta) from the Mexican Gulf of Mexico and Caribbean

The objective of this study was to contribute to the knowledge of the syllids distributed in the eastern coasts of Mexico (Gulf of Mexico and Caribbean) taking into consideration their composition, distribution and diversity. Sampling was done at 77 stations including 49 in soft bottoms (terrigenous and carbonate sediments), and 28 in hard bottoms (coralline substrates) sampled in nine reef zones included in three reef systems (Veracruz, Campeche and Cozumel). In all 2084 individuals were collected (13.5% in soft sediments and 86.4% in coralline areas). Forty-five species were identified: 31 in soft bottoms and 38 in corals, with 21 species common to both types of environments. In soft bottoms, the highest species richness and diversity were found in the Carbonate Zone, while syllids were uncommon in the Terrigenous Zone. In hard bottoms, the highest density, species richness and diversity values were found in the Veracruz Reef System, followed by the Campeche Bank and Cozumel Island Reef Systems. The dominant species in soft bottoms were Haplosyllis spongicola, Exogone lourei, Typosyllis cornuta and T. papillosus, whereas T. alosae, T. corallicola, T. cornuta and H. spongicola dominated in hard bottoms. The importance and success of the syllids in both soft bottoms and reef environments, particularly in those of the Gulf of Mexico is emphasized.     

A Mediterranean Fine-sand Polychaete Community and the Effect of the Tube-dwelling Owenia fusiformis DELLE CHIAJE on Community Structure

Samples were taken in fine-sand community of the North Latium coast in February and September for two years. Eigthy-eight species of Polychaetes were identified. The most abundant was Owenia fusiformis which was highly correlated to the clay fraction in the sediments. Species richness and abundance of other polychaete species were related to the abundance of this tubicolous species which provides a spatial refuge from predators and implements sediment stability. There was a persistency in the community structure in spite of seasonal fluctuations in the abundance of dominant species.     

The subtidal macrobenthic assemblages of Bahía San Sebastián (Tierra del Fuego,Argentina)

Bahía San Sebastián (BSS), a shallow and protected environment on the eastern coast of Tierra del Fuego (Argentina), is a prime habitat for several species of nearctic migratory birds that visit the area during summer to feed in its huge intertidal mudflats. The area has also great economic value due to the extraction and transport of hydrocarbons. Twenty-three dredge stations were analysed and presence/absence data were used to classify stations and species by cluster analysis. Two algae and 113 taxa of macrobenthic invertebrates from 12 animal phyla were identified. Species richness was one order of magnitude higher (mean 29.0 sp st⁻¹) in stations located outside or in the southern unprotected section of BSS than in most muddy or sandy stations within the bay (mean 3.7 sp st⁻¹). Hard bottom stations outside BSS were dominated by a rich assemblage of sessile filter-feeders, mainly bryozoans, hydrozoans, ascidians, sponges, and the bivalve Aulacomya atra. Soft bottom areas inside BSS were mainly populated by relatively few species of deposit-feeders, such as the orbiniid polychaete Phylo felix, which was particularly frequent and widespread. Shells of the clam Mulinia edulis are very common, representing one of the few hard substrata available for sessile species on soft bottoms. Epibenthic assemblages within BSS were dominated by the detritivorous isopod Serolis paradoxa and the crab Eurypodius latreillei. The macrobenthic fauna of BSS can be regarded as typical of the Magellan region, showing affinities with those of other localities around Tierra del Fuego, the Straits of Magellan and the southern Chilean fjords.     

Occurrence and settlement of the common shipworm Teredo navalis (Bivalvia: Teredinidae) in Bremerhaven harbours, northern Germany

The shipworm Teredo navalis L. is a xylophagous bivalve mollusc (Bivalvia: Teredinidae) with a long record of being very destructive to wooden ships and harbour buildings. It has been reported from numerous sites at the coasts of both the North and Baltic Seas since the eighteenth century. Here, we document for the first time the occurrence of live adult T. navalis in the harbours of Bremerhaven (Weser estuary, northern Germany). From August to December 1998, various wooden structures (fir floating fenders and pier posts, oak piles) from seven stations in different docks of two harbours (überseehafen, Fischereihafen) were investigated for the presence and density of live specimens and burrows of T. navalis. The settlement of larval shipworms was studied by exposing experimental fir panels 0.06 m² in size at 20 stations at water depths between 1 and 2 m for periods of 4 months between July and November. In addition, hydrographic profiles (0–8 m water depth) were obtained at 17 stations in five docks once every month from August to December. Live adult shipworms were found in both fir floating fenders and oak piles at four stations. The largest specimen found was 250 mm long. Shipworm burrows were detected at five stations in almost every wooden structure investigated but their abundances differed significantly: Maximum values were >10,000 m^–2 in fir floating fenders, 4,600 m^–2 in oak piles and 200 m^–2 in fir pier posts. Actual shipworm infestation was detected at three of 16 stations in the exposed fir panels (1–3 burrow holes per panel). Water temperatures and salinities varied considerably during the 4-month investigation period. Temperatures decreased from 19.9°C in August to 0.7°C in December. Salinities ranged from 17.6 in August to 1.1 in November, but only at two lock stations during November and December did value drop below 5, which is regarded as the lethal limit for the larvae of this euryhaline teredinid species. We conclude that T. navalis encounters favourable conditions for growth and reproduction in the harbours of Bremerhaven, at least during summer and autumn, and is a common element of the harbour ecosystem. Therefore, a persistent infestation of all wooden structures after a relatively short period of time seems to be highly probable. Electronic Publication     

A high local species richness and biodiversity within high-latitude calcareous aggregates of tube-building polychaetes

In general, biodiversity and species richness follow the latitudinal diversity gradient and decrease from the tropics towards the poles. Exceptions have however been recorded, as for deep coldwater coral reefs at high latitudes, which comprise biodiversity hotspots. Here we assess and characterise the high-latitude (69°N) species richness and diversity of a local shallow-water fauna associated with small calcareous aggregations of a serpulid polychaete. A dense and very species rich fauna was recorded within aggregations of Filograna implexa Berkeley, 1828. Totally 4663 individuals belonging to 99 species (61 solitary, 38 colonial) were recorded in a total aggregation volume of only 4.4 l covering an area less than 0.05 m² of a wreck situated in a tidal stream in North Norway. The number of species within each aggregation was positively related to its size, indicating that the high species diversity may be due to structural heterogeneity, which increase with aggregation size and probably creates new microhabitats and protect against predation. We present a species list including abundance and biomass, pin-point common species and describe a method for sampling such faunas associated with calcareous structures.     

Species richness of marine Bryozoa in the continental shelf and slope off Argentina (south-west Atlantic)

Abstract.  A total of 246 marine bryozoan species was recorded within an area of the south-west Atlantic between 35° and 56°S, and between the coast of Argentina and 50°W. The distribution pattern of benthic stations surveyed during the most important cruises in the area shows that the sampling effort has been biased towards southern shelf areas off Santa Cruz and Tierra del Fuego, as well as around the Malvinas (Falkland) islands. The littoral zone, Patagonian gulfs and the continental shelf off Chubut, Río Negro and Buenos Aires state received less attention, and should be surveyed more intensively in the future. Only 2% of the species can be regarded as non-indigenous, all of them inhabiting biofouling communities in harbour environments. With the exception of some thoroughly surveyed localities, the number of species recorded for different areas of the coast, shelf and slope is estimated to be just a small fraction of the actual number of species present. A distinct diversity gradient was found, with species-rich stations located only in the southern shelf. Highest diversity occurred in shelf areas dominated by coarse sediments, and along a high-productivity shelf-break front. A remarkable decrease in species richness was found in inner and middle shelf areas off Chubut, Río Negro and Buenos Aires state. This pattern may be related to the Pacific origin of the Magellanic fauna, since the diversity of bryozoans is higher in the Pacific than in the Atlantic Ocean. The trend of species richness is, however, overemphasized by the fact that the least diverse faunistic assemblage occurs in areas where surveys have been relatively less frequent. An up-to-date checklist of species recorded for the study area is included.     

Phytoplankton communities in water bodies at Dungeness,U.K.: analysis of seasonal changes in response to environmental factors

The species richness and the dynamics of the ciliatecommunitieswere studied at three stations along a streamlet formed bywaterdischarged from a geothermal sulphur spring. Altogether, 73specieswere identified. Ciliate coenoses were composed primarily offreshwater forms, but they were numerically dominated byeuryhalinespecies. The great fluctuation in both number of species andindividuals observed along the streamlet were due to vigorouschemical changes in the physico-chemical characteristics ofthewater. These changes were caused mainly by the sulphide andsaltgradient observed along the water course. The maximum value ofsulphide was observed in August with 391 µM l^–1, andthehighest conductivity value was observed in April with 18 mScm^–1. The most characteristic and abundant species weresmall-sized bacterivorous scuticociliates which have a rapidecological adaptability and whose tolerance limits toenvironmentalchanges are wide. Bacterivorous scuticociliates such as Cyclidium citrullus, C. glaucoma, Cinetochilummargaritaceum, and Uronema nigricans were numericallydominant when the thermal water contained the highestconcentrationof sulphide. The diversity index values changed sharply intimeboth inside and among sampling stations, indicating unstablecommunities which depended on highly fluctuatingconditions.     

Pollution effects in Visakhapatnam harbour,India: An overview of 23 years of investigations and monitoring

Visakhapatnam Harbour, a semi-enclosed water body on the east coast of India, is subject to a high degree of pollution caused by industrial and urban wastes. Studies carried out during the last twenty years or so at 6 selected stations in the harbour revealed appreciable hydrographic and biotic changes. Over the years, the concentration of nitrites (max. 5 mg/l) and phosphates (9.6 mg/l) has increased. Dissolved oxygen registered all-time-high values (max. 21.6 mg/l) caused by periodic outbursts of phytoplankton, notably,Skeletonema costatum and other species. Benthic conditions have also changed and only certain pollution-tolerant species (e.g.Capitella capitata) inhabited the bottom sediments that contained a heavy load (2.5%) of organic matter. In the harbour, increased pollution led to the disappearence of stenoecious species and their replacement with other forms known for their tolerance to pollution. The paper describes the major changes which have occurred in water quality and organisms in the harbour as a result of pollution increase during the last two decades.     

Influence du substrat sur la répartition des Crustacés stygobies interstitiels du Haut-Atlas occidental

The interstitial stygobiont distributions of two rivers in the western High Atlas is analyzed in relation with sediment granulometry. Sixteen stations were sampled along the rivers N'Fis and Zat and their tributaries. Granulometry analyses were performed. Three grain size sediment types constitute the subterranean biotopes and reflect the local hydrodynamical conditions. The main rivers stations, which undergo frequent natural or human disturbances, are characterized by a high content of fine sediment; in contrast, tributaries stations show coarse and well-classified sediments due to more stable biotopes and more regular hydrological conditions. The 92 taxa group 28 stygobiontic species with 11 crustaceans species. PCA. based on 16 stations, three faunistic richness indexes and three granulometric factors display a high correlation between coarse grain-size content and the richness of stygobiontic taxa. A high silt content both limits the interstitial taxa and excludes crustaceans that occur only in coarse gravels. The granulometric preferenda in the species of the amphipod genus Metacrangonyx and isopods Microcerberus. Microcharon and Typhlocirolana are shown on Shepard triangular diagrams. Cohabitation of several species of the same genus could be explained by the occupancy of different ecological niches resulting from the grain-size proportion.     

Early detection of potentially invasive invertebrate species in Mytilus galloprovincialis Lamarck, 1819 dominated communities in harbours

Constan?a harbour is a major port on the western coast of the semi-enclosed Black Sea. Its brackish waters and low species richness make it vulnerable to invasions. The intensive maritime traffic through Constan?a harbour facilitates the arrival of alien species. We investigated the species composition of the mussel beds on vertical artificial concrete substrate inside the harbour. We selected this habitat for study because it is frequently affected by fluctuating levels of temperature, salinity and dissolved oxygen, and by accidental pollution episodes. The shallow communities inhabiting it are thus unstable and often restructured, prone to accept alien species. Monthly samples were collected from three locations from the upper layer of hard artificial substrata (maximum depth 2?m) during two consecutive years. Ten alien macro-invertebrate species were inventoried, representing 13.5% of the total number of species. Two of these alien species were sampled starting the end of summer 2010, following a period of high temperatures that triggered hypoxia, causing mass mortalities of benthic organisms. Based on the species accumulation curve, we estimated that we have detected all benthic alien species on artificial substrate from Constan?a harbour, but additional effort is required to detect all the native species. Our results suggest that monitoring of benthic communities at small depths in harbours is a simple and useful tool in early detection of potentially invasive alien species. The selected habitat is easily accessible, the method is low-cost, and the samples represent reliable indicators of alien species establishment.     

Polychaete assemblages of a sub-arctic Newfoundland fjord: habitat, distribution, and identification

This study explores the association of 24 polychaete species with sandy and muddy habitats located in a sub-arctic fjord, and across Atlantic Canada including Labrador, Newfoundland, and the Gulf of St. Lawrence. Key characters used to facilitate species identification are also summarized. Within Bonne Bay, distinctive polychaete assemblages were associated with specific sediment types and polychaete species richness and density were significant both predictors of corresponding total (infaunal) density and species richness. Polychaetes were denser and more diverse in sandy sediments, partly because sandy locales were associated with the outer portion of the bay, and therefore were closer to the more productive and diverse Gulf of St. Lawrence. In general, species that occupied both sediment types were more widely distributed within Bonne Bay and across the region. The biogeography of most species also suggests that the Bonne Bay fauna is transitional between Labrador and Acadian biogeographic provinces.