bluuebunny/crossref_metadata_2025 huggingface dataset:
Recruitment of Demosponges (Porifera, Demospongiae) in Rocky and Coral Reef Habitats of Santa Marta, Colombian Caribbean*
Authors: Zea Sven
Published: May 2008

Abstract. Recruitment of demosponges (Porifera, Demospongiae) was monitored bimonthly for one year (March 1987 – March 1988) on acrylic plates, and compared to cover of adults, in six rocky and coral reef habitats at Santa Marta, Colombian Caribbean, an area subjected to seasonal, upwelling‐outwelling regimes. According to suggestive but not significant trends, recruitment rates are more positively influenced by the total sponge cover near groups of plates than by cover at a larger (habitat) scale; recruit mortality is lower where recruitment is higher. These findings are in agreement with a model of higher settlement (probably due to short‐distance dispersal) and lower postsettlement mortality within a few meters of adult sponges. Recruitment varied seasonally, being relatively high from May to November‐December during the rainy, outwelling season, when seawater temperature was warmer, water turbidity higher, and benthic algal density lower; it was very low from January to April during the dry, upwelling season.
Benthic Standing Stock and Metabolic Activity in the Bathyal Red Sea from 17°N to 27°N
Authors: Pfannkuche Olaf
Published: May 2008

Abstract. To study the impact of the gradient of primary production between the southern, central, and northern Red Sea, benthic metabolism and standing stocks were investigated in the axial trough between 17°N and 27°N. Data on sediment chloroplastic pigments, macrofauna and meiofauna abundance, particulate adenylate, protein and carbohydrate biomass, as well as electron transport activity of the sediment community give evidence for an enhanced benthic standing stock and activity in the southern Red Sea south of 18°N; this is related to the increased primary productivity in the area south 16°N. Despite a large primary production only small benthic standing stocks were found in all areas investigated; they are much smaller than in other parts of the world's deep oceans with comparable primary production. The low benthic biomass is caused by two factors: a large proportion of particulate organic carbon is remineralized in the water column, while only a relatively small amount sediments to the sea floor; nearly all sedimented particulate organic matter is respired by the benthic community of the deep Red Sea and only a minute proportion is used for the production of benthic biomass.

Euphotic zone primary production in the Red Sea decreases in a strong gradient from south to north. Highest primary production occurs south of 16°N. Benthic stocks of the Red Sea axial trough from 17°N to 27°N (water depth ≤ 1000 m), depending on the sedimentation rate of particulate organic matter from the euphotic zone, exhibited a corresponding south to north decrease in macro‐ and meiofauna abundance, biomass (particulate total adenylates, proteins, carbohydrates) and activity (ETS‐activity). All data give evidence for an enhanced benthic standing stock and metabolic activity south of 18°N. In contrast to other subtropical regions with comparable surface primary production, the biomass of the Red Sea benthos appears extremely low. This is caused by two factors: a large proportion of the sedimenting particulate organic matter is already remineralized in the water column, while only a small part reaches the sea floor; nearly all sedimented material is respired by the benthic community and only a minute proportion is channelled into biomass production.
Burrowing Behavior, Substratum Preference, and Distribution of Schizaster canaliferus (Echinoidea: Spatangoida) in the Northern Adriatic Sea
Authors: Schinner Gottfried O.
Published: May 2008

Abstract. Schizaster canaliferus, an endemic Mediterranean spatangoid, is common in the Bay of Piran (Northern Adriatic Sea). The abundance and distribution of this burrowing species is related to sea water depth and particle size distribution of the substrata. Populations are limited to silt/clay sediments in protected sublittoral areas of the Bay, where densities range from 1.9–2.6 individuals · m‐2. Preferred sediments range from medium to fine silt (2–20 μm). Burrowing activity was found to be functional only in fine sediments similar to those naturally inhabited; it did not occur in sandy sediments (>63μm). Burrowing rates were positively correlated with temperature, suggesting that burrowing speeds are greater in summer than winter. S. canaliferus is limited to the upper, oxygenated sediment layers and always burrowed just above the Redox‐Potential‐Discontinuity‐layer (RPD). At field study sites, the RPD ranged from 37 to 45 mm, while echinoid burrowing depths ranged from 30 to 45 mm. Laboratory manipulations of the RPD‐layer indicated that when this layer is displaced to 8cm depth, sea urchins responded by burrowing deeper, settling at depths just above the reoxygenated sediments. Populations of S. canaliferus in the Bay of Piran were randomly dispersed and size frequencies of individuals were unimodal, indicative of regular annual recruitment. 5. canaliferus is highly substrate specific and does not appear to be as widespread in the Adriatic Sea as earlier studies indicated. Its restricted distribution may be indirectly related to morphological constraints of the burrowing apparatus, which limits its occurrence to fine‐grained sediments within protected areas.

Schizaster canaliferus has been studied in the Bay of Piran (Northern Adriatic Sea). The abundance and distribution of this burrowing sea‐urchin is related to sea water depth and particle size distribution. Populations were limited to silt/clay sediments in protected sublittoral areas of the Bay. Burrowing activities were found to be functional only in fine sediments, similar to those naturally inhabited. Burrowing rates were positively correlated with temperature. S. canaliferus was limited to the upper, oxygenated sediment layers and always burrowed just above the Redox‐Potential‐Discontinuity‐layer (RPD). S. canaliferus is highly substrate specific and does not appear to be as widespread in the Adriatic Sea as indicated in earlier studies.
Seasonal Patterns of Dark Carbon Incorporation by Natural Phytoplankton Assemblages in the Central Cantabrian Sea (Bay of Biscay)
Authors: Fernanáez Emilio , Bode Antonio
Published: May 2008

Abstract. Phytoplankton dark carbon incorporation rates measured in the Central Cantabrian Sea (Bay of Biscay) exhibited a clear seasonal pattern. The highest rates were measured in May and September, whereas during winter very low rates were observed. Step‐wise regression analyses were performed with temperature, chlorophyll and the production/chlorophyll ratio as independent variables. The production/chlorophyll ratio was the most significant contributor (29.02%) on a yearly basis. Chlorophyll also explained a relevant percentage of dark carbon incorporation variability (15.36%), whereas temperature accounted for less than 0.5% of variance. Very similar results were obtained when mixing and stratification periods were analysed separately. The ratio between dark and light carbon incorporation showed high values (22–30 %) in January and March at all stations. During late spring and summer this ratio was low, ranging from 4 to 10 %. These results indicate a linkage between dark and light carbon incorporation and, therefore, that the subtraction of dark bottle counts could lead to underestimations of actual primary production rates, especially during low‐production periods.

Carbon incorporation rates integrated over the water column varied from less than 4 to more than 7 mg C · m‐2· h‐1, showing a marked seasonal pattern in close phase with the production/chlorophyll ratio. The highest rates were recorded in May and September at all stations. Verly low rates were measured in winter. Step‐wise regression analysis performed on the data revealed that the production/chlorophyll ratio explained the highest percentage of dark carbon incorporation variability (29.02%) on a yearly basis. The chlorophyll a concentration was also a relevant contributor (15.36%), whereas temperature explained less than 0.5 % of the variance. The percentage of dark to light carbon incorporation exhibited a clear seasonal variation. The highest percentages were measured in January and March. This ratio remained between 4 and 10.3% during late spring and summer.
Patterns of Coral Distribution and Benthic Space Partitioning on the Fringing Reefs of Southern Taiwan
Authors: Dai Chang‐Feng
Published: May 2008

Abstract. The distribution pattern of corals and benthic space partitioning patterns on the fringing reefs of southern Taiwan were studied by the line‐transect method. The bathymetric distribution of corals in the study area was basically homogeneous except on the protected reef slopes and the exposed reef fronts and terraces. Corals on protected reef slopes are mainly foliaceous, including Montipora foliosa, Merulina ampliata, Mycedium elephantotus, and Pachyseris speciosa, but the dominant species on a reef slope vary from site to site. The formation of the foliaceous coral community is possibly related to a complex of environmental factors, chance, and biological interactions. The reef fronts and submarine terraces of exposed areas are dominated by alcyonacean corals. The most abundant species are Sarcophyton trocheliophorum, S. crassocaule, and Lobophytum sarcophytoides; their distributions are relatively homogeneous. The formation of alcyonacean‐dominated assemblages can be related to the special adaptive strategies of these corals. In regard to space partitioning patterns, the major space occupiers on those reefs exposed to storm disturbances are alcyonacean soft corals, scleractinian corals, and algae; on reefs protected from storms, scleractinian corals and algae dominate. Two conspicuous features of the study area are the high proportion of space occupied by algae and the abundant unoccupied space. The dense algal cover is possibly caused by sewage pollution and overfishing of the reef area. The unoccupied space is most likely related to the high frequency of typhoon disturbances.
Ecology of the Symbiotic Coral Cladocora caespitosa (L.) (Faviidae, Scleractinia) in the Bay of Piran (Adriatic Sea): II. Energy Budget
Authors: Schiller Christian
Published: May 2008

Abstract. The temperate, symbiotic coral Cladocora caespitosa occurs naturally with variable numbers of zooxanthellae. This allows us to study differences in the physiology of symbiotic and “non‐symbiotic” polyps and to correlate them with zooxanthellae activities.

Zooxanthellae density in “dark” (normal‐colored) polyps was 50 times higher than in “white” (bleached) polyps.

The chlorophyll a content per zooxanthella was 3 times, and Chi c was 13 times higher in white polyps than in dark ones. O2‐flux experiments were conducted with colonies in situ and with single polyps ‐ dark and white ‐ under laboratory conditions. Two approaches were used to evaluate the contribution of zooxanthellae translocation products to animal respiration. Both revealed that the animal tissues derive a higher benefit from the zooxanthellae during periods of low water temperature than during warm periods.
The Diatom Nitzschia sicula (Castr.) Hust. and Naupliar Faecal Minipellets in the Adriatic sea
Authors: Viliĉć Damir , Krŝinić Frano , Biĉanić Zlatko
Published: May 2008

Abstract. Nitzschia sicula (Castr.) Hust., a planktonic pennate diatom, dominated the microphytoplankton (104‐5 times 104 cells. 1‐1) in the central, oligotrophic Southern Adriatic Pit waters (20‐50m layer) in May 1990. Nauplii dominated the microzooplankton (3 indiv. 1‐1in the 0‐50m layer, 130 μm mean body length) and produced a considerable amount of faecal (mini)pellets (1900. 1‐1 at 50m, mean diameter 47μm), which were compactly filled with N. sicula frustules. The subsurface accumulation of diatoms and nauplii was probably the result of both productive activity under specific hydrographic conditions and the convergence in a relatively strong southern Adriatic cyclonic gyre; the advective transport of populations along the shear zone, at the boundary between water masses of different thermo‐haline characteristics may also have played a role. The amount of minipellets was high if compared with the data available from other seas. This was probably due to high production of minipellets, their slow sinking rate, and/or an absence of manipulation of the faecal material by zooplankton.
A New Genus and Species of Rhynchonellid (Brachiopoda, Recent) from Submarine Caves in the Mediterranean Sea
Authors: Logan Alan , Zibrowius Helmut
Published: May 2008

Abstract. A new rhynchonellid brachiopod genus Tethyrhynchia, with type species Tethyrhynchia mediterranea n. sp., is described from specimens discovered in dark zones of submarine caves along the Mediterranean coast of France between Marseille and La Ciotat, and also at Zembra Island, off the Gulf of Tunis, Tunisia. Other brachiopods occurring with this diminutive rhynchonellid are also small and include the megathyridids Argyrotheca cistellula and Megathiris detruncata. This is the first recorded occurrence of a rhynchonellid from the Mediterranean Sea. The new form is apparently neotenous, in that the lophophore in adults never develops beyond the trocholophous stage. A new type of rhynchonellid crus, crescentic in profile and here named the lunifer type, is described. The new genus is assigned to the new family Tethyrhynchiidae, and comparisons are made with other extant rhynchonellid genera.
Plankton Distribution Patterns in a Mediterranean Dilution Basin: Amvrakikos Gulf (Ionian Sea, Greece)
Authors: Panayotidis P. , Pancucci M. A. , Balopoulos E. , Gotsis‐Skretas O.
Published: May 2008

Abstract. The present work describes Amvrakikos Gulf (Ionian Sea, Greece) as a dilution basin and provides information concerning the relationships between the hydrology and plankton composition and distribution.

Amvrakikos Gulf is characterized by a differentiated planktonic system which is apparently directly influenced by the input of the rivers located at the northern part of the gulf.
Resource Competition and Selective Grazing of Plankton in a Multispecies Pelagic Food Web Model*
Authors: Riegman Roel , Kuipers Bouwe R.
Published: May 2008

Abstract. An idealized mathematical, multispecies model of the pelagic foodweb was used to explore the impact of resource competition, selective grazing, and species composition within each trophic level on the structure and functioning of a foodweb at a variety of light irradiance and nutrient levels. This concept is based on the general assumption that poorly edible species are poor competitors. The concept demonstrates that with increasing eutrophication, specialists in competition will be replaced by generalists and subsequently by poorly edible primary producers. Controlling factors not only determine the growth rate of primary producers but also select predators according to their ability to utilize the energy fixation of the system. Plankton community structure seems to adapt in such a way that the energy fixation rate of the system is optimized at a given set of nutrients and light. Red tides, dense algal blooms in shallow lakes and the varying results of biomanipulation in shallow lakes, can be explained by the concept of selective grazing. If this assumption is correct, the same ecosystem concept may be applicable for terrestrial ecosystems.
The Interstitial Environment of Sandy Beaches
Authors: McLachlan Anton , Turner Ian
Published: May 2008

Abstract. The interstitial system of sandy beaches is lacunar and has its dimensions defined by the sand granulometry. It can be described by features such as pore size, porosity, permeability, and water content. The most important process occurring in this system, water filtration, is driven by inputs of freshwater from groundwater discharge, and inputs of seawater by tides, wave run‐up, and subtidal wave pumping. Reflective beaches have seawater input effected mainly by waves; they filter large water volumes with short residence times. Dissipative beaches display the opposite patterns, slowly filtering small volumes input by tides. Flow patterns and their effects on interstitial climate are described. The water table of the beach moves in response to groundwater discharge, tides, and waves and influences erosion/accretion processes on the beach face: a high water table promotes erosion. A series of moisture zones can be recognised from the dry surface sand at upper tide levels, to permanently saturated sand below the low tide water table, namely: a stratum of dry sand, a stratum of retention, a stratum of resurgence, and stratum of saturation. Interstitial chemistry is briefly described in terms of salinity changes, organic loads, oxygen content, and nutrient cycling. It is concluded that the interstitial environment of sandy beaches spans a continuum between physically and chemically controlled extremes: the former condition occurs on coarse sand reflective beaches, which experience low organic inputs and high filtration rates of large water volumes — resulting in powerful hydrodynamic forces; the latter occurs on dissipative beaches of fine sand, which are subject to high organic inputs and low filtration volumes — resulting in stagnation and steep vertical chemical gradients. Many intermediate situations occur and these are more favourable to interstitial life than either of the extremes.
Is the Determination of Meiobenthic Diversity Affected by the Sampling Method in Sandy Beaches?
Authors: Gourbault N. , Warwick R. M.
Published: May 2008

Abstract. Meiobenthic samples were collected by two different methods from the microtidal coralline sand beach at Gosier, Guadeloupe, West Indies: (I) vertical cores and (2) the Karaman/Chappuis (KC) technique of digging a hole and filtering the seepage water from the bottom. Nematode species diversity was unaffected by the sampling method, but nematode species composition differed. There was no evidence from statistical analysis to suggest differences in diversity or composition of higher taxa between sampling methods, although gastrotrichs appeared to be underrepresented by the KC technique.
Distribution of Living Larger Foraminifera NW of Sesoko‐Jima, Okinawa, Japan
Authors: Hohenegger Johann
Published: May 2008

Abstract. Living, symbiont‐bearing, larger foraminiferids restricted to the photic zone incorporate mechanisms blocking solar radiation and water current transportation. They can be divided in two groups according to their wall structure: 1, Families with opaque test walls, reducing light penetration: Peneroplids inhabit shallow‐water environments from the intertidal (Peneroplis in large numbers) down to 40 m (Dendritina, preferring sandy substrates). Soritids are restricted to subtidal environments with less water turbulence and range from the reef moat down to 60 m. Amphisorus and Marginopora are common down to 30 m, whereas Parasorites is restricted to deeper parts of the reef slope. Alveolinella can be found in the upper 40 m of the reef slope. 2. Families with hyaline test walls, adjusted for light penetration: amphisteginids inhabit the whole photic zone, demonstrating a correlation of test flattening with increasing depth. Calcarinids cling with their spines to firm substrates such as algal thalli or macroids. Baculogypsina is restricted to high energetic regions on the reef flat. Calcarina inhabits similar environments, extending its distribution range within fore reefs down to 80 m. Baculogypsinoides is a dominant calcarinid genus from 30 to 70 m depth. Within nummulitids, Heterostegina prefers hard substrates on the reef slope, while Assilina (= Operculina) is frequent in deeper parts and is independent of substrates. Sandy bottoms from 30 to 60 m are inhabited by the last living representative of the genus Nummulites, N. venosus. The giant foraminifer Cycloclypeus, with test sizes up to 7 cm, is restricted to fore reef areas below 50 m down to the base of the photic zone.
Local Distribution and Seasonal Variation of Fe, Pb, Zn, Cu, Cd, Na, K, Ca, and Mg Concentrations in the Seagrass Cymodocea nodosa (ucria) Aschers. in the Antikyra Gulf, Greece
Authors: Malea P. , Haritonidis S.
Published: May 2008

Abstract. The local distribution and seasonal variation of Fe, Pb. Zn, Cu. Cd, Na. K, Ca, and Mg concentrations in Cymodocea nodosa (ucria) Aschers., one of the most abundant seagrasses of the area. as well as their concentrations in the sediment and seawater were studied in the Gulf of Antikyra (Greece). The gulf is characterized by a bauxitic substrate and waste discharges from an aluminiumproducing factory. Many of the metals investigated constitute components of the two above‐mentioned metal sources.

The mean metal concentrations (± SE) in the seagrass decreased in the order: Ca > Na > K > Mg > Fe > Pb > Zn > Cd > Cu.

At the sampling stations A1, A2, A3, B3, and C1, where sufficient data was available for statistical analysis. the concentrations of metals in the plant did not vary significantly among stations (P > 0.05).

Metal concentrations in C. nodosa revealed two patterns of significant seasonal variation. The first pattern involved Fe, Cd, Na. and Ca and was characterized by high mean concentrations in summer and autumn. A reverse pattern was shown by Pb, Cu. and Mg. These patterns are discussed in relation to the growth dynamics. and leafage of the seagrass. the metal concentrations in the environment. the intermetal correlation, etc.

Cu, Cd, Pb, and Ca concentrations in the seagrass were significantly correlated with those in the sediment, whereas a direct relation of plant and seawater concentrations was obtained only for Ca and Mg. The intermetal correlation matrices in C. nodosa showed synergistic interactions between Cd‐Ca, Pb‐Mg, Fe‐Ca, Cu‐Pb, Na‐K, and Na‐Ca and antagonistic interactions between Cd‐Pb, Cd‐Mg, and Pb‐Ca.

The Cu, Cd, and Pb concentrations and the maximum Fe concentration in C. nodosa in the Antikyra Gulf are high compared with species belonging to the Cymodorroideae subfamily from other geographical areas.

Fe, Cu, Pb, Cd, Ca, Na, and Mg concentrations in C. nodosa displayed significant seasonal variation. The mean concentrations of Fe, Cd, Na, and Ca were high in summer and autumn. In contrast, Pb, Cu, and Mg concentrations were high in December and March. The concentrations of Fe, Cu, Zn, Cd, Pb, Na, K, Ca, and Mg did not vary significantly among the stations A1, A2, A3, B3, and C1 of Antikyra Gulf (Greece). Significant correlations were obtained between Ca and Mg concentrations in the seagrass and seawater and between Cu, Cd, Pb, and Ca concentrations in the plant and the sediment. Cd‐Ca, Pb‐Mg, Fe‐Ca, Cu‐Pb, Na‐K, and Na‐Ca showed positive correlations, whereas Cd‐Pb, Cd‐Mg, and Pb‐Ca showed negative correlations in the plant. Finally, the mean metal concentrations in C. nodosa decreased in the order: Ca > Na > K > Mg > Fe > Pb > Zn > Cd > Cu.

The concentrations of the heavy metals Cu, Cd, and Pb in C. nodosu in the study area are high compared with species belonging to the Cymodoceoideae subfamily from other areas.
A δ13C Study of the Feeding Habits in Four Mediterranean Leptomysis species (Crustacea: Mysidacea)
Authors: Dauby P. A.
Published: May 2008

Abstract. Mediterranean Leptomysis species are bentho‐nectonic shrimps living close to seagrass bed bottoms, forming swarms during the day and feeding on detritus and sedimentary organic matter during the night. As this matter is derived from different plant sources (phytoplankton, seagrasses, macro‐ and microalgae), assimilated carbon entering mysid tissues can hardly be identified on the basis of digestive tract analyses. Stable carbon isotope ratio measurements help to delineate food sources of the different studied Leptomysis species because plants are distinct isotopically. These 6°C measurements reinforce the view of the minor role of seagrass carbon in benthic food webs and of the importance of algae in the dynamics of these ecosystems.

Four Leptomysis species inhabit three relatively closely adjoining biotopes in the Gulf of Calvi: L. lingvura near the surface, forming shoals within rock blocks, L. posidoniae in Posidonia seagrass beds, and the couple L. heterophila +L. gracilis at the lower border of the infralittoral zone. These three biotopes are characterized by different main plant food sources (namely macroalgae, seagrasses, and phy‐toplankton), which are C isotopically well separated. δ13C measurements of the different Leptomysis populations show that these shrimps do not feed preferentially on the carbon source prevailing in their own biotope, but rather have an isotope ratio (‐16.5 to ‐20%0) close to the algal ratio. These observations can either be explained by feeding selectivity or by a differential assimilation rate of ingested material; in any case, they corroborate the role of algae in the trophodynamics of Mediterranean seagrass ecosystems.
Population Structure and Secondary Production of the Mediterranean Octocoral Lophogorgia ceratophyta (L. 1758)
Authors: Mistri M.
Published: May 2008

Abstract. The gorgonian Lophogorgia ceratophyta thrives in turbid water at Tinetto Rock, La Spezia Gulf, Ligurian Sea. Its age structure suggests that the population is in a steady state; nevertheless, it is difficult to discern whether the main factors controlling this population are biological or event‐related. Secondary production was estimated by means of an increment‐summation method and yielded 0.54 g ash‐free dry weight (AFDW)*m‐1 a‐1. This estimate does not take into account biomass losses due to reproductive output and non‐lethal predation. Standing stock biomass was 5.44 g AFDW e m‐2. The annual P/B ratio was 0.10 and turnover time about 10a
Nematode Community Structure Along a Mediterranean Shelf‐slope Gradient
Authors: Soetaert K. , Vincx M. , Heip C.
Published: May 2008

Abstract. Nematode assemblages along a Mediterranean depth transect (160–1220 m) and vertically in the sediment were investigated. The station at the edge of the continental shelf (160 m) was distinctly different from those situated on the continental slope (280–1220 m). On the slope, nematode communities in the upper centimetre differed significantly from communities in the deeper sediment layers, which were dominated by fewer and larger species. Vertical segregation could be a factor explaining the coexistence of several species belonging to the genus Sabatieria, with larger species penetrating deeper into the sediment. Clear differences in buccal morphology suggest food resource partitioning as the dominant factor promoting coexistence of several species belonging to the other dominant genus, Acantholaimus.
Behaviour of Cyclopoid, Harpacticoid, and Calanoid Copepods from Coastal Waters of Taiwan
Authors: Hwang Jiang‐Shiou , Turner Jefferson T.
Published: May 2008

Abstract. Cinematographic techniques were used to compare behaviour patterns of three cyclopoid, one harpacticoid, and two calanoid species of copepods from coastal waters of Taiwan. Behaviour was quantified in terms of allocation of time to swimming versus non‐swimming behaviour, and behavioural transitions/minute. The different species of copepods exhibited different patterns of behaviour. Oithona nana and O. similis had long periods of inactivity punctuated by comparatively few transitions to intermittent leaps of motion. Oncaea venusta had a more jerky pattern of numerous small hops with frequent transitions between motion and rest. Macrosetella gracilis spent more time swimming than did the cyclopoids, but with fewer behavioural transitions than O. venusta, more like the Oithona species. Temora turbinala swam virtually continuously and transitions to non‐swimming were rare. Undinula vulgaris var. taiwanicus frequently alternated between upward motion and sinking at rest, making a feeding current about a fourth of the time. There was considerable intraspecific variability between individual animals, but for reasons of experimental design, it was impossible to statistically test the significance of this variation. Differences in behaviour patterns between the different species are discussed within the context of what is known about the feeding ecology of these species from previous investigations.
The Fauna of Floating Cyanobacterial Mats in the Oligohaline Eulittoral Zone off Hiddensee (South‐west Coast of the Baltic Sea)
Authors: Vopel K. , Arlt G.
Published: May 2008

Abstract. The fauna — including macrofauna, meiofauna, and large ciliates — of floating cyanobacterial mats in a brackish shallow‐water area was studied by analysing six 20 cm2 pieces of mat. Although these microbial aggregations were scarcely 1 cm thick, their total meiofauna abundance was about five times as high as in the uppermost 4 cm of the adjacent sediment. The mat fauna was dominated by harpacticoids, although large ciliates, rotifers, nematodes, and oligochaetes were also markedly more abundant than in the sediment. All species occurring in the mats were members of the surrounding sediment fauna. Out of the 47 species found, only a few, among them predominantly the harpacticoid, Mesochra lilljeborgi Boeck, 1864, and the nematode Daptonema setosum (bütschli, 1874), accounted for the majority of the individual abundance in the mats. Both are regularly found in sulphidic biotopes near Hiddensee. As SEM micrographs revealed, the oligochaete Paranais litoralis (O. F. Müller, 1788) and the harpacticoid Cletocamptus confluens (Schmeil, 1894) were apparently optimal substrates for dense lawns of cyanobacteria. This indicates possible close interactions between the meiofauna and these microbiota. The frequent predation of histophagous ciliates on nematodes and harpacticoids, which were probably weakened by oxygen deficiency and/or high sulphide concentrations, were not only a sign of a generally neglected pathway in the food chain, but also impressively emphasized the huge variety of interactions taking place between meio‐ and microfauna within this specific benthic microcosm. Because of their floating character, the mats can play an important role in the dispersal of benthic fauna.
Mediterranean Marine Reserves: Fish Indices as Tests of Protection Efficiency
Authors: Harmelin J.‐G. , Bachet F. , Garcia F.
Published: May 2008

Abstract. The fish assemblages of a strictly protected area and of a neighbouring fished area, located off a Mediterranean urbanized coast (Carry‐le‐Rouet, France), were compared in order to select the most evident, constant, and easily recorded indices of the ‘reserve effect’. Visual censusing was repeated simultaneously at both sites eight time a year during 3 years along four permanent transects layed on shallow rocky bottoms (9–14 m). Overall species richness was 16% higher in the reserve, but differences in average instantaneous richness were only marginally significant. The most contrasting results were shown by the occurrence frequency, abundance, and demographic structure of two types of target species. The type A target species group comprises 16 large meso‐ and macrocarnivores particularly threatened by spearfishing, including the common nectobenthic sparids Diplodus spp. Type B target species are represented by two small territorial fishes particularly impacted by angling: the serranid Serranus cabrilla and the terminal phase males of the labrid Coris julis. The size structure of Diplodus spp., S. cabrilla, and C.julis subpopulations strongly argues for the role of protected areas as a reservoir of large spawners. Fishing pressure is assumed to modify the social conditions of the C. julis local populations and to induce earlier sex change.
Occurrence of Spadella cephaloptera During One Year at Ischia Island (Gulf of Naples)
Authors: Goto T.
Published: May 2008

Abstract. The life cycle of the benthic arrowworm, Spadella cephaloptera, which inhabits the Posidonia meadow at Ischia (Gulf of Naples, Italy), was examined by a one‐year systematic sampling survey and by laboratory culture. The seasonal fluctuations in abundance and the reproductive characteristics indicate that there were two generations of S. cephaloptera in one year; these generations have a different life span. The habitat of S. cephaloptera depends on the growth of the Posidonia meadow; the influence of different factors on the S. cephaloptera population, especially of the Posidonia vagile fauna, is discussed.
Observations on the Microbial Biomass in two Stations of Terra Nova Bay (Antarctica) by ATP and LPS Measurements
Authors: Ferla R. La , Allegra A. , Azzaro F. , Greco S. , Crisafi E.
Published: May 2008

Abstract. This paper reports on the temporal distribution of microbial biomass, over a I‐month survey during austral suinmer 1990. at two sampling stations in Terra Nova Bay (Antarctica) by means of biochemical methodologies such as ATP (adenosine triphosphate) and LPS (lipopolysaccharides). Microbial estimates. derived from ATP measurements. showed an unstable temporal trend and a range characteristic for water with low or. seldom. moderate trophism. Biomass decreased with increasing depth. and photo‐autotrophic organisms seem to dominate the whole microbial assemblage. The bacterial population, as derived from LPS determinations, did not show much variability and was well‐correlated to other microbiological and chemical parameters. Our data showed that larger mic‐roplankters were dominant. but that sometimes pico‐sized organisms contributed about 60% to the microbial biomass; this emphasizes the ‘still poorly‐known’ importance of microbes in Antarctic food webs.
Hurricanes Cause Population Expansion of the Branching Coral Acropora palmata (Scleractinia): Wound Healing and Growth Patterns of Asexual Recruits
Authors: Fong P. , Lirman D.
Published: May 2008

Abstract. Three mechanisms aiding recovery and expansion of a population of Acropora palmata on a patch reef that was directly in the path of Hurricane Andrew were documented: rapid wound healing, high rates of asexual recruitment, and rapid growth rate of the new recruits. In addition, the growth pattern of new recruits was assessed in order to quantify the initial sequence of Structural changes during the transition from recruit to adult morphology. Wound healing was initially rapid (1.59 cm of linear growth per month). but slowed with time. Nine months after the storm, 72% of 218 hurricane‐generated fragments of A. palmata had cemented to the bottom, becoming new asexual recruits. Within 18 months of the storm, the number of fragments in the same area had increased to 271, average fragment size was larger, and 94% had become recruits. Recruits showed complex patterns of branch formation, including rapid growth of solitary proto‐branches, differential growth of proto‐branches dependent on recruit orientation, and dominance within aggregates of proto‐branches. We present a conceptual model that suggests A. palmata is adapted to disturbances of both low intensity and high frequency (conditions typical of reef flat zones) and episodic high intensity and low frequency events (hurricanes and tropical storms).
Macrofauna Associated With Sponge Species of Different Morphology
Authors: Koukouras A. , Russo A. , Voultsiadou‐Koukoura E. , Arvanitidis C. , Stefanidou D.
Published: May 2008

Abstract. The macrofaunas associated with the three morphologically different North Aegean Sea sponge species Agelas oroides, Aplysina aerophoba, and Axinella cannabina were compared. The faunal abundance was not related to sponge surface area for any of the three species. Each sponge species supported a significantly different number of individuals per unit canal volume; A. aerophoba supported the most, A. oroides the least. A. aerophoba supported the highest species richness, A. cannabina the lowest. Canal volume was a good predictor of associated faunal abundance and species richness for two of the three sponge species. Faunal abundance was also directly related to sponge mean canal diameter. The species composition of associated fauna was similar on A. aerophoba and A. oroides and significantly different on A. cannabina.
Trophic Structure and Community Composition of Polychaetes Inhabiting Some Sabellaria alveolata (L.) Reefs Along the Valencia Gulf Coast, Western Mediterranean
Authors: Porras R. , Bataller J. V. , Murgui E. , Torregrosa M. T.
Published: May 2008

Abstract. A total of 24 samples from Sabellaria alveolata reefs have been collected and subjected to cluster analysis using the trophic dominance of each feeding guild as grouping variables. The result is the arrangement of samples by colony physical structure and S. alveolata dominance.

Relating cluster groups to reef development phases reveals an inverse relationship between reef growth and the organization of the associated polychaete taxocoenosis. During the growth phase of the reef, S. alveolata dominates the community, excluding other taxa from colonization. Growth is followed by the destruction phase. Negative physical and biological factors for reef enlargement may open patches on the reef surface, allowing recruitment of other species and colony erosion. The end of this phase is represented by eroded reefs with high structural complexity and high species richness.

Sabellaria alveolata reefs reported from 13 localities in the study area have been classified according to their structural features into two main types: a) developed reefs, with considerable volume and a shape independent of the underlying substrate and b) eroded reefs, which form tiny encrusting plates covering the substrate. Based on cluster analysis each one of these may be subdivided according to SAQD values.
The Brittlestar Amphiodia urtica; A Candidate Bioindicator?
Authors: Maurer D. , Nguyen H.
Published: May 2008

Abstract. The ophiuroid Amphiiodia urtica Lyman is presently under study as a potential wastewater discharge indicator species from ocean outfalls in the Southern California Bight. On the San Pedro Shelf, the maximum abundance of A. urtica was found at depths from 30 to 100 m, and in sediment with a median grain size of 0.085 nim, 60–80% sand. 15–30% silt, 0–37% clay, and 0.2–0.5% TOC. The mean abundance of A. urtica fluctuated annually with a slight increase from 1977 through 1993.

The hypothesis was posed that the distribution and abundance of A. urtica is not influenced by an ocean outfall and its operation on the San Pedro Shelf. Based on long‐term (1977–1994) and intensive (2860 samples) sampling. the hypothesis was rejected. However, the effect of the outfall is not clear because sediment bioassays from test stations and controls produced no significant differences in survivorship and growth of juveniles. Amphiodia presently occupies areas within the Zone of Initial Dilution (ZID) where it was not found during the mid‐1970s and early 1980s. While recognizing that A. urtica abundance responds to proximity to the outfall, the mechanism for this response is still unclear. The application of a single species as a bioindicator is not recommended, and most certainly not without fully essing its role in community structure and function.
The Influence of the Cockle, Cerastoderma edule, on the Macrozoobenthic Community of Tidal Flats in the Wadden Sea
Authors: Flach Els C.
Published: May 2008

Abstract. The cockle Cerastoderma edule is one of the large and important species of the tidal flats of the Wadden Sea. C. edule disturbs the upper sediment layer due to its crawling and “shaking” behaviour. About 7% of a cockle population move within one week. The mean distance of movement is ‐4 cm per week, which, in the case of a 2‐year‐old cockle with a length of ˜3 cm, means that ˜20 cm2 of sediment is disturbed to a depth of ˜3 cm. Besides these measurable movements, cockles also regularly “shake” themselves, thereby disturbing the sediment around them to at least ˜0.5 cm. At a density of 500 cockles per m2 of a mean length of 3 cm, ˜16% of the sediment surface is occupied by cockles and another ˜29% is disturbed by cockles within one week.

To study the effects of cockles on recruitment of other benthic species, densities of 0, 125, 250, 375 and 500 cockles (mean length 3 or 3.5 cm) were added to 1‐m2 plots within large depopulated squares in April. Subsequently, sediment samples were sieved once a month (from June to September) and the densities of all macrozoobenthic species were estimated. The presence of cockles significantly reduced the densities of juveniles of the bivalve species C. edule, Macoma balthica, Mya arenaria, Tellina (Angulus) tenuis, and Ensis directus and of the worm species Pygospio elegans, Lanice conchilega, Eteone longa, Anaitides spec., Nephtys hombergii, Heteromastus filiformis, Scoloplos armiger, and Tharyx marioni and of the amphipods Corophium volutator and C. arenarium. Non‐significant effects were found only in Capitella capitata and Nereis diversicolor. For all species mentioned above a negative effect was already observed at the lower cockle densities of 125 ‐ 250 per m2. Reductions of about 50% or more were found at densities of 500 per m2, which was more than could be expected based on the area occupied by the cockles (˜16%), but close to the area occupied plus disturbed (˜45%). It is concluded that (dense) assemblages of adult cockles can have a strong influence on the macrozoobenthic community.
Meiobenthic Organisms as Indicators of Mixing Processes in the Baltic Surface Sediments*
Authors: Pempkowiak Janusz , Kozuch Joanna , Szymelfenig Maria
Published: May 2008

Abstract. Two sediment cores were collected in the southern Baltic Sea and sliced into 1.0cm‐thick layers. Sediments of each layer were analysed for activities of 210Pb, 137Cs, 134Cs and for the density of meiobenthic organisms (meiofauna).

Zones with the rapid mixing occur in the uppermost layers (0–3 cm) of the cores based on I34Cs profiles. The extent and density of meiofauna confirmed the rapid mixing and revealed layers with slow mixing (4–8 cm). Sedimentation rates were derived from 210Pb profiles below the mixing zones (1.21 and 1.72 mm a‐I) and were confumed by 137Cs distribution. Of twenty‐one major meiofauna taxa commonly found in the Baltic sediments, three were present in the cores.
The Effect of the Introduction of the American Species Marenzelleria viridis (Polychaeta; Spionidae) on the Benthic Ecosystem of Vistula Lagoon
Authors: ŻMudziński Ludwik
Published: May 2008

Abstract. In the late 1980s, a radical change in the macrozoobenthos composition occurred in the Vistula Lagoon, an oligohaline and silted water basin. This structural change is a result of the mass appearance of the very strongly euryhaline spionid polychaete Marenzelleria viridis Verrill, a newcomer from North American estuaries. It considerably reduced the previous bottom macrofauna, which was composed mainly of Chironornidae larvae and oligochaetes.

The penetration depth of the macrozoobenthos into the sediments and its total biomass increased in the last years, which enhanced the organic matter displacement in sediment layers of a greater thickness. The previous bottom dwellers inhabited mainly the most superficial sediment layer, whereas the new polychaete immigrant can penetrate down to a depth of 20–40 cm.
The Black Sea Ecosystem Changes Related to the Introduction of New Mollusc Species
Authors: Zolotarev Valentin
Published: May 2008

Abstract. The unintentional introduction of the new mollusc species Rupunu rhomasiuna, Mya arenaria, and Scuphurcu inaequivulvis has become a significant reason for modern transformations of certain bottom biocoenoses in the Black Sea. These molluscs have been passed across natural barriers in fouling of ships or in ship seawater ballast and have successfully acclimatized in the new region, forming communities with a high density and biomass. The resulting changes in the structure of the bottom biocoenoses after these introductions are in many cases comparable with or exceed the consequences of other episodic environmental events and other kinds of anthropogenic activity. The intense spreading of the introduced species in the new area is the result of their high adaptive capability and the instability of the Black Sea ecosystem, the latter being due to its few species, low level of competitive interactions, and constant growth of diverse anthropogenic loads.
Episodic Events: Their Relevance to Ecology and Evolution
Authors: Boero Ferdinando
Published: May 2008

Abstract. An episodic event can be one of the many “episodes” forming a normal flow of related events. But it can also be an “incident” interrupting a trend and initiating a new one. Appreciation of contrasting meanings of apparently identical categories of phenomena is familiar to evolutionary biologists who, for instance, envisage evolution as the result of both gradual and punctuated events. Seasonal plankton blooms (both normal and noxious), species outbreaks, mass mortalities, and human predation are taken as examples of “episodes” that can influence and/or modify what we perceive as “normality”. Recruitment is another example of an episodic event heavily conditioning both community structure and function, as recently highlighted by the so‐called supply‐side ecology. The reductionistic study of ecology. more linked to thermodynamics than to history, allowed the formulation of general ecological laws which, however, stem from the laws of thermodynamics. The totalizing value of such laws blurs appreciation of heterogeneity and change, so that many ecologists tend to be rather conservative, using a concept like “conservation” as an absolute paradigm to follow and to consider “change” as an a priori negative phenomenon. Episodes can have a “conservative” or “innovative” meaning, and are the driving force of the history of life. Their importance is recognized mainly when dealing with the history of organisms (evolutionary biology), whereas the assemblages of organisms (i.e., communities) are too often described and interpreted in an ahistorical context or in a too narrow time frame. Recognition of the importance of history in ecology (evolutionary ecology) can lead to a better understanding of environmental dynamics, albeit restricting the supposed predictive strength of ecology, a science timely integrating the reductionistic‐thermodynamic approach with the holistic‐historical one.
Episodic Mass Invasions of Juvenile Gadoids into the Wadden Sea and their Consequences for the Population Dynamics of Brown Shrimp (Crangon crangon)
Authors: Berghahn Rüdiger
Published: May 2008

Abstract. The brown shrimp Crangon crungon is considered to be a key species in the coastal waters of the North Sea and in particular in the Wadden Sea, since it occurs in masses and acts as both a highly efficient predator and important prey. The Wadden Sea is the nursery ground for brown shrimp. In 1990, a mass invasion of O‐group whiting (Merlangius merlangus) reduced Crangon numbers to almost zero. Similar events, which had previously been reported in the 19th century, were observed in 1959 (whiting), 1970 (cod, Gadus morhua), and 1983 (cod and whiting).

The 1990 invasion and the decline of the shrimp stock are documented on the basis of surveys that are compared with the years preceding and following. Consequences for the food web in the Wadden Sea and the reasons for the complete recovery of the shrimp stock in each case within one year after its collapse are discussed with regard to the Crangon crungon behaviour and reproductive potential. Sampling error and the impact of fisheries are also considered.