bluuebunny/crossref_metadata_2025 huggingface dataset:
Marine benthic faunal successional stages and related sedimentary activity
Authors: Rosenberg Rutger
Published: October 2008

This paper is a brief review of successional stages and activity of benthic soft-bottom communities. Benthic communities was first described by Petersen in the 1910s and further developed by Molander, Thorson and Margalef. Successional stages of benthic communities chance in a predictable way in relation to environmental disturbance and food availability. Food supply to the bottom can occur as a vertical flux, but transport through lateral advection is more important in some areas. While at the bottom, the infauna processes the food in many different ways, and the feeding modes can be categorised into more than 20 functional groups, but fewer are present in brackish water. This categorisation is based on animal mobility and where and how they ingest the food. Animal activity in the sediment, bioturbation, has a significant effect on redox conditions and diagenetic processes. Structures in the sediment due to infaunal presence and activity can be observed in situ by sediment profile imaging, and the biogenic structures and redox conditions can be parameterised and have been shown to correlate to benthic community successional stages. The largest threat to benthic faunal biodiversity is the spread of near-bottom oxygen deficiency in many enclosed are stratified coastal areas.
Landscape challenges to ecosystem thinking: Creative flood and drought in the American Southwest
Authors: Fisher Stuart G. , Welter Jill , Schade John , Henry Julia
Published: October 2008

Stream ecology is undergoing a transition from ecosystem to landscape science. This change is reflected in many studies; work at Sycamore Creek in Arizona will be used to illustrate the challenges of this transition and several applications. Conceptual challenges involve clear determination of the organization of research objectives. Ecosystem science is largely concerned with how things work while landscape ecology focuses on the influence of spatial pattern and heterogeneity on system functioning. Questions of system scale, hierarchical structure, dimensionality, and currency must be resolved in order to productively execute research objectives. The new stream ecology is more integrative, more realistic spatially, deals with streams at a larger scale, and treats them as branched system more than former approaches. At Sycamore Creek, studies of sand bar patches and their influence on organisms and nutrient cycling illustrate how variations in patch shape and configuration can alter system outputs. Beyond sandbars, inclusion of riparian zones as integral parts of streams produces a more coherent view of nutrient dynamics than previous studies that began at the water´s edge. Integration of streams with the landscape they drain requires that streams be viewed as branched structures, not linear systems. This view in ecology is in its infancy but it provides an opportunity to identify processing hot spots along flow paths and to reveal presumptive effects of climate change in terms of spatial shifts in biogeochemical activity rather than black-box rate changes.
Atlas of Northwestern Mediterranean Coccolithophores
Authors: Cros Lluïsa , Fortuño José Manuel
Published: October 2008

The present Atlas contains a detailed study, based in scanning electron microscopy (SEM) observations, of living coccolithophores from NW Mediterranean waters. The study contains 103 figures with 411 micrographs, which correspond to 168 coccolithophores (including different taxonomic and morphotypic entities). The figured specimens were collected during different cruises carried out from 1995 to 1999.Classification of the organisms follows modern taxonomy of living calcareous nannoplankton. Measures of the specimens and notes on their taxonomy are given in addition to abridged descriptions of the studied taxa. The atlas contains a large number of previously undescribed forms, specially in the genera Syracosphaera, Papposphaera, Polycrater, Anthosphaera, Corisphaera and Sphaerocalyptra. Several species never illustrated in the literature are presented here for the first time. Coccospheres having coccoliths of different recognized species are presented. These combination coccospheres are nowadays considered as transitional steps between different phases in the cellular life-cycle. An introduction with a brief overview of the actual coccolithophore knowledge and an abridged glossary with figures of the basic terminology are included.
Geographical patterns in abundance and population structure of Nephrops norvegicus and Parapenaeus longirostris (Crustacea: Decapoda) along the European Mediterranean coasts
Authors: Abelló Pere , Abella Álvaro , Adamidou Angeliki , Jukic-Peladic Stjepan , Maiorano Porzia , Spedicato María Teresa
Published: October 2008

The main characteristics concerning distribution, size structure and total mortality of two of the most important decapod crustaceans of commercial interest in the Mediterranean Sea, Nephrops norvegicus and Parapenaeus longirostris, are studied along the European Mediterranean coasts. The study is based on data collected during a series of six trawl surveys performed in spring from 1994 to 1999 from the Gibraltar Straits to the Aegean Sea. The population size structure identified in the different geographical sectors is analysed taking into account two bathymetric sectors: continental shelf and upper slope. Differences in N. norvegicus population demographic structure among geographical sectors, as well as in total mortality, appear to be highly related to different exploitation levels. Size structure in P. longirostris also shows a great heterogeneity throughout the different geographical sectors. Considering that both species are heavily exploited all along the studied area, the observed differences can be interpreted as different responses to exploitation related to the widely differing life history characteristics of the mentioned species. In fact, N. norvegicus is a long-lived, benthic, burrowing species with low growth and mortality rates, and P. longirostris an epibenthic short-lived species characterised by higher rates of growth and mortality.
Distribution of the Mediterranean hake populations (Merluccius merluccius smiridus Rafinesque, 1810) (Ostheichthyes: Gadiformes) based on six years monitoring by trawl-surveys: some implications for management
Authors: Orsi Relini Lidia , Papaconstantinou Costas , Jukic-Peladic Stjepan , Souplet Arnauld , Gil de Sola Luis , Piccinetti Corrado , Kavadas Stefanos , Rossi Marco
Published: October 2008

On the basis of trawl survey data collected during the MEDITS project (1994-1999), the distribution of Mediterranean hake populations was described in coastal areas corresponding to about three quarters of both the latitudinal and longitudinal extensions of the Mediterranean Sea, and in the 0-800 m range. Abundance and biomass indices (in terms of number and kg per km2) are presented in 15 geographical sectors and 40 subareas from the Alborán Sea to the Aegean Sea. A statistical analysis by generalized linear modelling performed on such indices per main national blocks (Greece, France, Italy and Spain), and considering the effects of the six years of sampling and the depth, showed that biomass increased from west to east, while for all areas the most significant depth effect appeared between 100 and 200 m, corresponding to the depth range that hosts most of the summer nursery areas. The overall size-frequency distributions in shelf and slope waters, average sizes and total mortality coefficient Z per sector showed that the bulk of the MEDITS samples consisted of young individuals and, with only a few exceptions (western Sardinia, central Aegean), a generalized condition of growth overfishing was apparent. However, no negative trend was found, either in biomass or in average size of fishes, during the six years of the present study. Recruitment patterns were studied by distinguishing the youngest fish as Gaussian groups (modal length from 6 to 9 cm total length) in length-frequency distributions of each subarea and main stratum (shelf and slope). Considering the timing of MEDITS surveys (May-July), this approach emphasised the nurseries in the northern part of the western Mediterranean (Gulf of Lions, Ligurian Sea, northern Tyrrhenian Sea) and in the northern central Mediterranean, where recruitment occurs mainly during spring. On the other hand, few recruits were found in part of the central and particularly in the eastern Mediterranean, where recruitment occurs mainly in summer. MEDITS recruitment patterns therefore gave support to distinctions among Mediterranean hake populations, previously suggested on the basis of vertebral counts and other morpho-physiological, albeit fragmentary, data. In particular the central Mediterranean hake populations do not seem to be homogeneous, with an Adriatic unit very close to the northwestern one. The MEDITS experience therefore suggests that future management measures could take into account both general and regional patterns, the latter concerning mainly the younger fraction of the populations.
STATIS-CoA: A methodological solution to assess the spatio-temporal organization of species assemblages. Application to the demersal assemblages of the French Mediterranean Sea
Authors: Claude Gaertner Jean , Bertrand Jacques A. , Souplet Arnauld
Published: October 2008

The organizational patterns of demersal assemblages (fish, crustaceans and cephalopods) in the Gulf of Lions were investigated on the basis of a set of six bottom trawl surveys performed between 1994 and 1999 (MEDITS programme). The use of a recent multitable method (STATIS-CoA) provided a detailed representation of the stable and variable parts of the spatial organization of demersal assemblages during the studied period. We showed that demersal assemblages of the Gulf of Lions were organized along a coast-open sea gradient. At the scale of the Gulf, we showed that this gradient can be split into three areas: 1) the coastal region and the continental shelf (10 to 200 m depth), 2) the upper slope (200 to 500 m) and 3) the deeper slope (500 to 800 m). Associated to this bathymetric structuring we found a species-richness gradient which decreases from the coast to the upper slope. Our analysis showed that this spatial organization pattern was highly persistent during the course of the study. However, some species caught in the slope area exhibited a strong variability of their spatial distribution mainly during the 1999 survey. From a methodological point of view, STATIS-CoA offers a rigorous theoretical framework for the simultaneous analysis of a three-dimensional set of data. Applied in the field of fisheries ecology, this method (1) constitutes a relevant way to analyse the spatial organization of species assemblages and its pattern of changes, and (2) could be of particular interest to treat the MEDITS data both at a local and at the North Mediterranean Sea scales.
Trends in the abundance of demersal species in the southern Aegean Sea
Authors: Tserpes George , Peristeraki Panagiota
Published: October 2008

The present work identifies trends in the abundance of the main demersal species of the South Aegean Sea utilising catch and effort data derived from an international Mediterranean bottom trawl survey (MEDITS). The experimental surveys were accomplished annually from 1994 to 2000 on 61 pre-defined sampling stations. Selection of stations was based on a depth-stratified random sampling scheme that included five depth strata: 10-50, 50-100, 100-200, 200-500 and 500-800 m. The results suggest the existence of a general increasing trend in the biomass of the demersal species, particularly at the 10-50 m and 500-800 m depth strata. Findings are discussed in relation to the fisheries exploitation pattern and productivity of the area.
Marine benthic algae of Namibia
Authors: Rull Lluch Jordi
Published: October 2008

The first comprehensive study of the marine algal flora of Namibia including descriptions and illustrations of most species is presented. The main objective of this work is to report a flora that, until now, has scarcely been studied. The work compiles all the available information on the marine benthic flora of Namibia and provides new data about it composition and biogeography, as well as detailed descriptions and remarks of most of its species. The samples on which this study is based were collected between 1986 and 1989 in the eulittoral and the upper sublittoral zones of the north half of the Namibian coast. According to the present data, the marine benthic flora of Namibia comprises 196 taxa (147 Rhodophyceae, 20 Phaeophyceae, 15 Ulvophyceae, 6 Cladophorophyceae and 8 Bryopsidophyceae), 21 of which has not been recorded from this coasts. This temperate flora is mainly characterized by a low number of species, a low proportion of Phaeophyceae and a high degree of endemism. Concerning the species number, the flora is quite poor due to both the scarce availability of colonizable substratum and the low diversity of habitats. On the other hand, the low proportion of Phaeophyceae is the reason for which the R/P and (R+C)/P ratios take disproportionately high values and so they are not useful in this geographical area. As regards the degree of endemism, the marine benthic flora of Namibia includes quite a high number of taxa endemic to southern Africa (55 taxa; 28.1% of the flora); 25 of these 55 taxa (12.8% of the flora) are endemic to the biogeographic Benguela Marine Province and only Acrosorium cincinnatum is endemic to the Namibian coasts.
Inverse relationship between cod recruitment in the North sea and young fish in the continuous plankton recorder survey
Authors: Lindley John A. , Reid Philip C. , Brander Keith M.
Published: October 2008

There is a significant (p
Sardine regime shifts off Portugal: a time series analysis of catches and wind conditions
Authors: Borges M. F. , Santos A. M. P. , Crato N. , Mendes H. , Mota B.
Published: October 2008

Decadal changes have been observed in the annual catch of sardine (Sardina pilchardus W). Long-term changes have also been observed in alongshore winds off Portugal in the last decades in winter months. During sardine spawning season (winter), northerly winds that favour upwelling led to unfavourable conditions for egg and larval survival. By using time series analysis, we investigated the effect of wind conditions and North Atlantic Oscillation (NAO) on the sardine catches, in the period from 1946-1991. We also investigated the time lag between recruitment strength and its turnout in catches. We concluded that recruitment is forced to a lower level when the frequency and intensity of northerly wind exceeds a certain limit in winter. Our time series retrospective analyses led to evidence of climatic driven regime-shifts in West Portugal sardine productivity in late 1960s-early 1970s. These results are discussed in terms of their implications in fisheries management plans.
Stock dynamic of the Iberian sardine (Sardina pilchardus, W.) and its implication on the fishery off Galicia (NW Spain)
Authors: Carrera Pablo , Porteiro Carmela
Published: October 2008

The recent failure of sardine catches off Galicia (NW Spain), an area where landings reached up to 100 thousand tonnes only a few years ago, may be explained by two possible hypotheses. The ";depletion"; hypothesis states that diminishing sardine catches were due to a decrease in stock biomass resulting from a combination of reduced recruitment and increased fishing mortality. The ";change in distribution"; hypothesis states that catch failure was due to a change in the distribution of the stock owing to environmental changes. Available information, based on direct observations from acoustic and ichthyplankton surveys and the fishery, was analysed. When the stock size is high, the spawning area of the sardine extends offshore in the Cantabrian Sea, and spreads along the continental shelf off northern Portugal. Moreover, adult fish undertake feeding migration towards Galician waters. This spawning behaviour results in a recruitment located mainly off Portugal. Low stock size causes a shrinkage in the distribution area throughout coastal waters and in the Cantabrian Sea, reaching the inner part of the Bay of Biscay. This process also affects the migration range and favours a higher retention in coastal waters of the early life stages (from eggs to recruits), which remain primarily in the same area where they were hatched. The lack of sardine in Galicia may be explained by a depletion process which affects both the feeding migration of adult fish and the recruitment occurrence off southern Galicia. This paper also analyses the dynamics of this stock in the context of a metapopulation. Taking this concept into consideration, we also examined the influence of the dynamics of each sub-population and the environmental conditions that might affect the success of the recruitment.
Fish stock assessments in the Mediterranean: state of the art
Authors: Lleonart Jordi , Maynou Francesc
Published: October 2008

The Mediterranean fisheries are characterised by fragmented fleets, usually composed by relatively small vessels, use of a large number of landing sites, multi-species catches and low CPUEs. Fish are commercialised mainly fresh and the prices are relatively high. These factors make it difficult and expensive to get extensive and reliable data time series and to get biological samples. Most of the fish caught in the Mediterranean are the recruits (0-1 year old) of the main target species. Since the recruitment is much more uncertain than the abundance of the adult stages, the assessments are also more uncertain. Furthermore, no TAC or adaptive management is in place, so the administrations do not require monitoring in order to manage the fisheries. The continental shelf is narrow (with some exceptions) and there are few stocks shared between two or more countries. Consequently, the international management structures have not been sufficiently enforced, and until recently no regular assessments were made by international working groups. These characteristics have led to a situation in which most of the assessments have been done in the framework of scientific projects, and therefore do not have continuity in time. The results of these assessments have rarely been incorporated in management.
Quality of fisheries data and uncertainty in stock assessment
Authors: Chen Yong
Published: October 2008

The quality of fisheries data has great impacts on the quality of stock assessment, and thus fisheries management. In this paper, using a case study I evaluate the impacts of two types of error, biased error and atypical error, that can negatively affect the quality of fisheries data in stock assessment. These errors are commonly associated with fisheries data, and assumptions on their sources and statistical properties can have great impacts on the outcome of stock assessment. Although the sources and statistical properties of these errors differed, both of them could result in errors in stock assessment if estimation methods are not appropriate. Different statistical approaches used in fitting models differ in their robustness with respect to errors of different statistical properties in data. This study showed the importance of evaluating the quality of input data and the possibility of developing an approach that is robust to errors in data. Considering the likelihood of fisheries data being affected by errors of different statistical properties, I suggest that the robustness of a stock assessment be evaluated with respect to data quality.
Integrative fish stock assessment by frequentist methods: confidence distributions and likelihoods for bowhead whales
Authors: Schweder Tore
Published: October 2008

Frequentist concepts of confidence distribution, reduced likelihood and likelihood synthesis are presented as tools for integrative statistical analysis, leading to distributional inference. Bias correction, often achieved by simulations, is emphasised. The methods are illustrated on data concerning bowhead whales off Alaska, and they are briefly compared with Bayesian methods.
Occupancy rates and nesting success of European storm-petrels breeding inside artificial nest-boxes
Authors: De León Ana , Mínguez Eduardo
Published: October 2008

We report on occupancy rates and nesting success of European storm-petrels Hydrobates pelagicus breeding in artificial nest-boxes for five years. Plastic nest-boxes were installed inside two natural caves on the island of Benidorm (western Mediterranean), where breeding colonies of the species occur. The location of nest-boxes was (a) over exposed natural nests or (b) at sites without nests, but usually close to them. Nest-boxes were visited during the breeding season following installation, when only nest-boxes over old nests were occupied. Occupancy rates in both types of nest-box increased gradually year after year, reaching 29% in the fifth year. Nesting success of pairs breeding inside boxes was higher than nesting success of pairs breeding at natural sites.
Managing seabird metapopulations in the Mediterranean: constraints and challenges
Authors: Oro Daniel
Published: October 2008

In recent times metapopulation models have contributed important insights to conservation, and they have inspired field studies that focus on collecting key data on demography and movement. Seabirds are suitable models for studying ecological processes in metapopulations because they breed in discrete local populations (i.e. colonies) both in space and time. However, in the Mediterranean, seabird colonies mostly show conservation problems at an ecosystem level, linked to human activities (e.g. fisheries, tourism, industrial pollution) and the resulting loss of habitat and deterioration of habitat quality. From a conservation point of view, it is crucial to study transfer processes in seabird metapopulations (i.e. emigration, immigration and colonisation) in order to propose management measures. Conservation agencies should always take into account these processes and the spatial factor involved in metapopulation dynamics. However, it is difficult to estimate demographic parameters at a metapopulation level because of technical and financial constraints. In addition, there is a need to act at large geographical scales, since seabirds are wide-ranging species, which operate in ranges beyond political boundaries and far greater than those encompassed by traditional management practices.
Status of the Balearic shearwater (Puffinus mauretanicus) on the Galician coast (NW Iberian Peninsula
Authors: Mouriño Jorge , Arcos Francisco , Salvadores Rafael , Sandoval Antonio , Vidal César
Published: October 2008

This paper aims to assess the status of the threatened Balearic shearwater Puffinus mauretanicus along the Galician coast (NW Iberian Peninsula) by studying its movements and numbers. Balearic shearwaters are detected off Galicia during their annual cycle although they are uncommon between November and May. Overall, 44 groups of over 150 birds have been recorded in seven main areas since 1976, especially in the Vigo Ria and the Pontevedra Ria and along the coast of Bergantiños (Sisargas-Baldaio). Birds have been observed moulting primary and secondary feathers, mainly in June. North-eastward migration is evident along the Atlantic coast (capes Silleiro and Fisterra, daily maximum of 476 birds per hour) between June and August, where it seems to overlap with local movement. However, south-westward migration is far more frequent between September and October (daily maximum of 360 birds per hour) along the Cantabrian coast. The results might be biased due to the methodological problems, on account of the existence of irregular flows, an important inter-annual variability and local movements, probably brought about by the distribution of food resources.
Impact of fisheries on activity, diet and predatory interactions between yellow-legged and Audouin's gulls breeding at the Chafarinas Islands
Authors: González-Solís Jacob
Published: October 2008

Interactions between yellow-legged Larus cachinnans and Audouin´s Larus audouinii gulls and fisheries operating around the Chafarinas Islands, located 4.5 km off the Moroccan Mediterranean coast, are reviewed. At the Chafarinas archipelago two distinct types of fisheries operate: trawlers and purse seines. Gulls take advantage of both fisheries. They scavenge trawler discards and congregate around shoals of fish attracted to the surface by the purse-seine lamps. When both trawlers and purse-seine boats are in operation, the diet of both gull species is similar, with epipelagic fish accounting for over 60% of the biomass, partially collected in association with the purse-seine fishery. When only trawlers operated yellow-legged gulls, but not Audouin´s gulls, augmented their diet mainly with human waste from refuse dumps, suggesting that competition for food between the two species is mainly limited to the periods when resources made available by fishery activities are abundant. Likewise, when only trawlers operated, there was an increase in the predation pressure on eggs and chicks of Audouin´s gulls. In particular, during the week of celebrations for the holy lamb festival when neither fishery operated, egg losses of Audouin´s gull increased dramatically, suggesting that severe food shortage caused by the cessation of fishing can result in an increased predation pressure by yellow-legged gulls, affecting Audouin´s gull productivity. These results suggest a novel socio-ecological link between gulls, fisheries and local feasts.
Evidence for enhanced primary production resulting from relative vorticity induced upwelling in the Catalan Current
Authors: Granata Timothy C. , Estrada Marta , Zika Ulrike , Merry Carolyn
Published: October 2008

In baroclinic fronts, jets and eddies, potential vorticity, P = (V + f) / D, connects horizontal motions of planetary vorticity, f, and relative vorticity, V, to vertical transport through increases and decreases of the water column height, D. In this paper we present evidence that positive changes in relative vorticity of the SW flowing Catalan Current and meandering of the coastal jet follow the 500 m isobath and are associated with topographic steering by offshore canyons. Generally, positive relative vorticity is a result of cyclonic torque that generates cyclonic flow causing the water column to upwell since both P and the volume of the flow are conserved. With coastal jets that flow over abrupt topographies, such as deep canyons, D increases and flow must take on a cyclonic circulation, favoring upwelling conditions. In the case of a westward flowing current, we would expect the flow to acquire a cyclonic vorticity upstream of the canyon but to enter at the canyon obliquely (Cushman-Roisin, 1994) causing downwelling. Upwelling in meandering coastal jets can also occur when horizontal streamlines diverge, unable to adjust to relative vorticity changes, and fluid parcels near the edge of the front separate. Using pycnocline thickness as an indicator of D, we show that deep canyons stretch the water column causing cyclonic meandering (positive relative vorticity), upstream of the canyon during the FRONTS cruises 1991 to 1993. This phenomena has been shown to cause upwelling upstream of meander troughs (Onken, 1992) which in this case would mean upstream of canyons. We hypothesize that the increased relative vorticity, associated with upwelling in the pycnocline, fuels episodic primary production across the front accounting for more than 30% of the new production in this coastal zone.
Phenology of Caulerpa taxifolia and temporal dynamics of its epibiontic meiofauna in the port of Malinska (Croatia, northern Adriatic Sea)
Authors: Travizi Ana , Zavodnik Nevenka
Published: October 2008

The qualitative and quantitative composition of epibiontic meiofauna were studied in the C. taxifolia settlement recently recorded in the Malinska port (Krk Island, northern Adriatic Sea). The samples were taken monthly, from May 1998 till June 1999 covering the complete life cycle of C. taxifolia. In total, 14 meiofaunal taxa were recorded. The meiofauna assemblage was characterized by the dominance of Copepoda (58%), the subdominant position of Nematoda (25%), and the low single participation of other taxa. The results of monthly monitoring indicated a seasonal trend in meiofaunal distribution. The beginning of the summer was a period of a low meiofaunal abundance (139 ind. sample-1), and also a start of its exponential increase. The autumn was characterized by a fairly high abundance (~1000-1500 ind. sample-1) and moderate variation of the constituent taxa levels. During the winter exponential growth (to about 10000 ind. sample-1) and high faunal diversity was detected. In subsequent months meiofaunal abundance reached over 19.000 ind. sample-1 - remaining extremely high until May when C. taxifolia fronds disappeared. The increase of meiofaunal abundance was positively correlated with the increase of the algal frond´s length during the summer-autumn period, and with the increasing quantity of sediment particles and detritus accumulated on algal fronds during the C. taxifolia vegetative cycle. This study has shown that C. taxifolia can provide a suitable habitat for numerous benthic invertebrates, although it is known as a species that reduces the benthic biodiversity.
Mechanisms regulating amphipod population density within macroalgal communities with low predator impact
Authors: Christie Hartvig , Kraufvelin Patrik
Published: October 2008

In eight mesocosms (land based basins) macroalgae communities with associated fauna were transplanted from the sea and established during two years. Then, different doses of nutrients (N and P) were added to the basins throughout the following three years. During the period of nutrient addition, macroinvertebrate grazers showed seasonal fluctuations with densities usually between 500,000 and 1 million individuals per mesocosm during summer and to a level of about 100,000 during winter. The macroinvertebrate grazers mainly consisted of about 10 species of amphipods and isopods, among which the amphipod Gammarus locusta dominated strongly by biomass. Although the number of predators was very low, the grazer populations never reached a density where considerable grazing impact could be found on the macroalgae. No increase in grazer density was found in the basins with improved nutrient conditions. Thus food quality may be insufficient for further population growth, or density dependant regulation mechanisms may have prevented the grazers from flourishing and overgrazing the system. In aquarium experiments we showed that G. locusta could grow and reproduce on Fucus serratus, Ulva lactuca, periphyton and detritus, and that cannibalism by adult G. locusta on juveniles may have great impact on the population growth. The basins were run with a water flow through system. Nets were placed in front of the inflow and outflow tubes to measure immigration and emigration. Only few individuals (and no Gammarus sp.) were recorded in the inflowing water, while high numbers of both amphipods and isopods were found in the outflowing water. Emigration reached peak values during night-time, and it was then two to three times as high as during day-time. Emigration of mobile grazers from the basins amounted to 1-2% of the standing stock daily. These mechanisms that regulate grazers do contribute to maintenance of the seaweed dominance and thus the stability of the seaweed community.
Demography of the over-exploited Mediterranean red coral (Corrallium rubrum L. 1758)
Authors: Santangelo G , Maggi E. , Bramanti L. , Bongiorni L.
Published: October 2008

The precious octocoral, Corallium rubrum, endemic to the Mediterranean, has long been overexploited. A demographic approach to the conservation and management of this species would therefore be highly valuable. To this end, a coastal population of red coral was studied in detail. The population represents a true "genetic unit", as it is mainly "self-seeding". It is moreover gonocoric, and the sex ratio is significantly biased toward females. For this study, 4408 colonies, collected from 28, 300-cm2 samples, were divided into 10 size (age) classes. Recruits represent about half the population. The frequency of colonies in each class decreases exponentially with colony size. On these bases, an "ad hoc" life history table has been updated to include the mortality and reproduction coefficients actually measured in the population. The major reproductive output is due to the first 3 reproductive classes (79%), while larger colonies, although having higher reproductive coefficients, are sparse and only account for a small portion of the population overall reproductive output. The ratio of larval survival to adult density found indicates that some density-dependent limitation of population growth is likely at play in the population under study. Such results will be important for understanding dynamics of red coral disturbed or exploited populations.
Amphipod and Sea Urchin tests to assess the toxicity of Mediterranean sediments: the case of Portmán Bay
Authors: Cesar A. , Marín-Guirao L. , Vita R. , Marín A.
Published: October 2008

The sediment formed by the tailings of an abandoned mine, which discharged into Portmán Bay, Murcia, SE-Spain, was tested to establish a possible gradient of heavy metals. The results were compared with tolerance limits of what was calculated from control sites. Whole sediment toxicity tests were performed on two amphipod species, Gammarus aequicauda and Microdeutopus gryllotalpa, while sediment-water interface and porewater toxicity tests were performed on three sea urchins species, Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis. The sensitivity of these marine organisms was evaluated by exposure tests using the reference substances: ammonium chloride (NH4Cl), cadmium chloride (CdCl2), potassium dichromate (K2Cr2O7), sodium dodecyl sulfate (C12H25NaO4S) and zinc sulfate (ZnSO4). The concentration of heavy metals decreased along the pollution gradient. Amphipod 10 day acute toxicity tests clearly demonstrated the gradient of toxicity. The sediment-water interface tests conducted with sea urchins also pointed to a pollution gradient and were more sensitive than the tests involving amphipods.
Community structure and diversity of demersal fish assemblages: the role of fishery
Authors: Labropoulou Mary , Papaconstantinou Costas
Published: October 2008

Seasonal experimental trawl surveys were carried out in the Northern Aegean and Thracian seas (NE Mediterranean, Greece), from summer 1990 to autumn 1993, during which a total of 172 fish species were caught. In these areas, fishing pressure is very high, since approximately 50% of the Greek otter trawl fleet operates there, producing more than 57% of the total demersal landings. Different statistics were used to assess spatial structure, seasonal changes and diversity of the demersal fish assemblages on the continental shelf and upper slope. The following measures were applied to the species abundance matrix: species diversity, species richness, evenness and dominance. The analysis of 501 bottom trawls revealed that, in general, species diversity, richness and evenness decreased with water depth, with the highest values at depths 200 m. The effect of depth on the diversity patterns observed was always significant, while seasonal trends were similar with those described for the overall diversity characteristics in each area. Classification and ordination methods showed the existence of 4 groups associated with the continental shelf and upper slope in each area. Classification of the top ranking species at each group and area revealed that commercially important species were dominant in the shallowest zone (
Culturable vibrios biodiversity in the Northern Ionian Sea (Italian coasts)
Authors: Cavallo Rosa Anna , Stabili Loredana
Published: October 2008

Vibrio spp. in the marine environment play an important role in biodegradation, nutrient regeneration and biogeochemical cycling. These microorganisms are normal residents in coastal waters and their numbers depend on environmental parameters. The qualitative and quantitative composition of culturable Vibrio spp. in water samples from the Northern Ionian Sea (Italy) was investigated. The study was carried out from December 1999 to November 2000 in 10 stations along the coast line between Castellaneta Marina and Santa Maria al Bagno. Seasonal distribution of culturable vibrios densities showed the highest values during the summer-autumn period. Furthermore, in all the examined sites vibrio abundance was higher at the stations nearest the shore. During the sampling period 387 Vibrio spp. strains were isolated. Vibrio mediterranei was the predominant species, V. nereis and V. harveyi also represented two consistent components of the isolated culturable vibrio community. V. alginolyticus and V. parahaemolyticus showed a mean isolation percentage of about 7%. Recovery of some vibrio species was correlated with temperature. Data provided in this study will improve our understanding of the distribution of Vibrio species in the Northern Ionian Sea.
Observations on the distribution, population structure and biology of Bathypterois mediterraneus Bauchot, 1962 in three areas of the Mediterranean Sea
Authors: D'Onghia Gianfranco , Lloris Domingo , Sion Letizia , Capezzuto Francesca , Labropoulou Mary
Published: October 2008

During the DESEAS cruise Bathypterois mediterraneus specimens were sampled in the Balearic Sea between 1000 and 2800 m as well as in the western and eastern Ionian Sea from 800 to 3300 m and from 800 to 2600 m respectively. The species was found to be more abundant at depths of 1500-2000 m. The size-range was 26-190 mm and the most abundant size class was around 100-120 mm standard length. No significant size-depth trends were shown for either length or weight. Negative allometry was shown in the growth of fishes and otoliths and in the relationship between fish length and otolith size in the samples from the western and eastern Ionian Sea. In these two areas the absolute growth was estimated by adopting the Von Bertalanffy function (western Ionian: SL∞ = 194.3 ± 38.51 mm, k = 0.146 ± 0.061/year, t0 = - 0.921 ± 0.699, ø' = 3.74; eastern Ionian: SL∞ = 180.23 ± 63.36 mm, k = 0.150 ± 0.112/year, t0 = - 0.968 ± 0.868, ø' = 3.70). Although most of the specimens were immature, some ripe gonads were recorded in individuals greater than 104 mm in standard length, confirming the simultaneous hermaphroditism in this fish. The results are discussed in relation to previous observations on the life strategy of B.mediterraneus in the Mediterranean Sea.
Interdisciplinary oceanographic observations: the wave of the future
Authors: Dickey Tommy D. , Bidigare Robert R.
Published: October 2008

Oceanographic measurements, though difficult and expensive, are essential for effective study, stewardship, preservation, and management of our oceanic and atmospheric systems. Ocean sciences have been driven by technologiesenabling new observations, discoveries, and modelling of diverse interdisciplinary phenomena. Despite rapid advances inocean sampling capabilities, the numbers of disciplinary variables that are necessary to solve oceanographic problems arelarge and increasing. In addition, the time and space scales of key processes span over ten orders of magnitude; presently, there remain major spectral gaps in our sampling. Thus, undersampling presents the main limitation to our understanding of global climate change; variability in fish biomass and regime shifts; and episodic and extreme events. Fortunately, recentadvances in ocean platforms and in situ autonomous sampling systems and satellite sensors are enabling unprecedented rates of data acquisition as well as the expansion of temporal and spatial coverage. Consequently, improved sampling strategies will lead to a reduction in ocean forecasting error for predictions of a multitude of atmospheric and oceanic processes. Nonetheless, major challenges remain to massively increase the variety and quantity of ocean measurements and to effectively coordinate, synthesize, and distribute oceanographic data sets. In particular, numbers of measurements are limited by the costs of instruments and their deployment as well as data processing and production of useful data products and visualizations. Looking forward, many novel and innovative technologies involving computing, nanotechnology, robotics, information and telemetry technologies, space sciences, and molecular biology are being developed at a fast pace for numerous applications (Kaku, 1997; Kurzweil, 1999). It is anticipated that several of these can and will be transitioned to the ocean sciences and will prove to be extremely beneficial for oceanographers in the next few decades. Already, autonomous, ‘robotic’ in situsampling, high spectral resolution optical and chemical instrumentation, multi-frequency acoustics, and biomolecular techniques are being utilized by a limited number of oceanographers. Also, increased temporal and spatial sampling capabilities for expanding numbers of interdisciplinary variables are being accelerated thanks to both new technologies and utilization of data assimilation models coupled with autonomous sampling platforms. Data networks coupled with internet connectivity are rapidly increasing access to and utilization of data sets. In this essay, we review recent technological progress for solving some key oceanographic problems and highlight some of the foreseeable challenges and opportunities of ocean science technologies and their applications.
Circulation in the Mediterranean Sea: evidences, debates and unanswered questions
Authors: Millot Claude
Published: October 2008

The overall counterclockwise alongslope circulation of Atlantic Water (AW) in the western basin of the Mediterranean Sea is now generally accepted. As the eastern basin displays similar general features, why is it generally assumed to function in a different way, and why is AW now said to circulate across the interior of the eastern basin? Relatively huge mesoscale anticyclonic eddies induced by the instability of the AW circulation in the south of the western basin have lifetimes up to several years. It is possible that they extend down to the sea bottom and play a major role in the distribution of all water masses. Why have apparently similar eddies generated in the eastern basin never received specific attention? Once formed, Mediterranean Waters (MWs) must spread and circulate before outflowing. Why have simple dynamical arguments for understanding the circulation of AW, such as the Coriolis effect, rarely been considered for the circulation of MWs? In this paper we address these major aspects of water circulation in the Mediterranean Sea. In order to be as objective and convincing as possible, and to write a paper that can be understood by as broad a readership as possible, we have chosen to present only raw data sets that can be easily interpreted by the reader without any help from the author. Based on the evidence provided by these data sets, we specify the current debates and list what we think are the main unanswered questions.
The bivalves from the Scotia Arc islands: species richness and faunistic affinities
Authors: Zelaya Diego G.
Published: October 2008

Species richness of the shallow-water bivalves from the Scotia Arc islands was studied on the basis of new collections and by reviewing extant information. Seventy-three species are recognised from the entire area. South Georgia, the South Orkney Islands and the South Shetland Islands were similar in species richness to the Antarctic Weddell sector. New records for 51 bivalve species are provided and the presence of 18 undescribed species is reported. The faunistic similarity of the islands of the Scotia Arc to the Magellan region and the Antarctic Weddell sector is re-examined. These islands show a high similarity to the Antarctic Weddell sector (49 to 85%) and a low similarity to the Magellan region (12 to 32%). Evidence from bivalves clearly supports the placement of the Scotia Arc islands within the Antarctic region.
Diversity and endemism in cold waters of the South Atlantic: contrasting patterns in the plankton and the benthos
Authors: Boltovskoy Demetrio , Correa Nancy , Boltovskoy Andrés
Published: October 2008

In total, ca. 7000 zooplanktonic species have been described for the World Ocean. This figure represents less than 4% of the total number of known marine organisms. Of the 7000 zooplanktonic species world-wide, some 60% are present in the South Atlantic; about one third of the latter have been recorded in its Subantarctic waters, and ca. 20% south of the Polar Front. When compared with those of benthic animals, these figures indicate that proportions of the overall inventories that are present in the cold waters are almost two times higher among the zooplankton. In agreement with this pattern, the proportions of Antarctic endemics in the benthos are very significantly higher than those in the plankton. For the water-column dwelling animals, the Polar Front boundary is more important than the Tropical-Subtropical limit, but almost equivalent to the Subtropical-Transitional limit, and weaker in biogeographic terms than the Transitional-Subantarctic boundary. Some of the implications of these dissimilarities, both for ecological theory and for resource allocation strategies, are discussed.
Ascidians (Tunicata, Ascidiacea): species distribution along the Scotia Arc
Authors: Tatiàn Marcos , Antacli Julieta Carolina , Sahade Ricardo
Published: October 2008

Ascidians are found in all the oceans. The Polar Front is considered a strong barrier, especially for benthic organisms, separating the Southern Ocean from other oceans. Its influence on ascidian species present at the boundary of the Magellan and Antarctic regions along the Scotia Arc and on the species composition at each station is inferred from the samples taken during the “LAMPOS” cruise. Ascidians were collected by Agassiz (AGT) and bottom (GSN) trawls at depths between 250 and 587 m on different types of substrate. Of 25 identified species/morphospecies one is new and eight were found in new localities, enlarging the known range of five of these species. Muddy bottoms were found to support higher species richness than hard bottoms, and the South Georgia Islands are found to be the northern limit for Antarctic species and the southern limit for Magellan ones. Affinity between the ascidian fauna of the Magellan region and the Antarctic is slightly stronger than was previously considered; there is also a species gradient along the Scotia Arc, which can be regarded as a bridge between the two regions.
Soft-bottom macrobenthic faunal associations in the southern Chilean glacial fjord complex
Authors: Ríos Carlos , Mutschke Erika , Montiel Americo , Gerdes Dieter , Arntz Wolf E.
Published: October 2008

Macrobenthic associations were investigated at 29 sampling stations with a semi-quantitative Agassiz trawl, ranging from the South Patagonian Icefield to the Straits of Magellan in the South Chilean fjord system. A total of 1,895 individuals belonging to 131 species were collected. 19 species belong to colonial organisms, mainly Bryozoa (17 species) and Octocorallia (2 species). The phylum Echinodermata was the most diverse in species number (47 species), with asteroids (25 species) and ophiuroids (13 species) being the best represented within this taxon. Polychaeta was the second dominant group in terms of species richness (46 species). Multidimensional scaling ordination (MDS) separated two station groups, one related to fjords and channels off the South Patagonian Icefield and the second one to stations surrounding the Straits of Magellan. 45 species account for 90% of the dissimilarity between these two groups. These differences can mainly be explained by the influence of local environmental conditions determined by processes closely related to the presence/absence of glaciers. Abiotic parameters such as water depth, type of sediment and chemical features of the superficial sediment were not correlated with the numbers of individuals caught by the Agassiz trawl in each group of sampling stations.