bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactions Between Small Sciaphilous Scleractinians and Epizoans in the Northern Mediterranean, With Particular Reference to Bryozoans
Authors: Harmelin Jean‐Georges
Published: May 2008

Abstract. Two small sclcractinians, Lepfopsummiu pruvoti (solitary) and Hoplungiu dur‐olrix (colonial, aggrcgatcd or not), which arc common pcrcnnial componcnts of Mcditcrrancan submarinc cavcs and dccp vcrtical walls, bcar many cpibionts on thc lowcr part of thcir corallitcs. Samplcs were collectcd ncar Marscillcs (7–58 in) undcr various cnvironmcntal conditions and coral densitics. Frequency of occurrencc of thc major cpizoan groups and of individual bryozoan spccics overgrowing the corallites varies according to habitat charactcristics and to acccssibility of the individual corallitcs for adjaccnt epizoans. Thc most frcqucnt colonizcrs arc: bryozoans (by vcgctative growth and larval settlcrnent), sponges (mainly by vcgctativc growth), and scrpulids. Among the 40 recorded bryozoan species (26 on Leptopsammia, 28 on Hoplangiu), 15 spccics are relatively frequent on each host. Comparisons of data from the corallites with thosc obtained from adjoining samples indicatc the preference for coral substratc of Pucflina radiata. This encrusting bryozoan is highly predominant on both Leptopsammia and Hoplangiu as well as on other scleractinian species. SEM observations show that overgrowth processcs are reversible and that corals may control the invading encruSters by embedding them in their sclerenchyme. The balance and benefits of this epizoan/host system are discussed.
Analysis of Benthic Communities in the Cyclades Plateau (Aegean Sea) Using Ecological and Paleoecological Data Sets
Authors: Zenetos Argyro , Papathanassiou Evangelos , Aartsen Jacobus J. Van
Published: May 2008

Abstract. In the Cyclades plateau (Aegean Sea), a qualitative and quantitative analysis of macro‐benthic fauna was carried out in 1986. Standard multivariate analysis techniques were applied to both ecological (living benthic fauna) and paleoecological data sets in order to distinguish distribution patterns.

Results showed that caution must prevail in drawing conclusions from a limited data set. The clearest classification was obtained using total living fauna, while the dead molluscan fauna gave a similar pattern; this indicates similar response to the environmental conditions of the area. In the analysis of the living molluscan fauna, the groups failed to show any clusters, probably as an effect of some impoverished sites.

In the two groups delineated, depth seems to be the major factor in the distribution of species.

The fact that two distinct data sets (subfossil assemblages and living communities), when treated separately, produce similar grouping indicates that the subfossil assemblages could be reliably used as a first approach for determination of the living communities' distribution patterns.
Epimenia arabica spec, nov., a Solenogaster (Mollusca) Feeding on the Alcyonacean Scleronephthya corymbosa (Cnidaria) from Shallow Waters of the Red Sea
Authors: Salvini‐Plawen Luitfried v. , Benayahu Yehuda
Published: May 2008

Abstract. The body organization and some biological data of Epimenia arabica, a new species of Sotenogastres of the order Cavibelonia, are presented. The species is described based on four large‐sized specimens (13–21 cm × 0.7‐1 cm) from three different localities off the coast of the Sinai Peninsula (Red Sea). It feeds on Scleronephthya corymbosa Verseveldt & Cohen (Octocorallia: Alcyonacea), generally at depths of 2–5 meters.
Ontogenetic Shifts in Resource Use and Shoaling Tendency Related to Body Size in Red Sea Goatfish (Parupeneus forsskali, Mullidae)
Authors: Uiblein Franz
Published: May 2008

Abstract. Red Sea goatfish show marked behavioral differences related to body size in food searching, substrate use, and shoaling tendency. While smaller fish mainly use their barbels to search for food hidden in the upper sediment layers or in crevices of corals, the largest fish frequently burrow with their mouths in deeper layers of the sediment. The conspecific shoaling tendency decreases with increasing size. Only smaller‐sized fish are found in mixed‐species shoals. The data are discussed with regard to the relations between ontogenetic changes in body size, resource utilization, and socialization patterns.
Deposit Feeding and Sediment:
Authors: Amon Rainer M. W. , Herndl Gerhard J.
Published: May 2008

Abstract. The effect of defecation and decomposition of fecal pellets egested by the deposit feeding Holothuria tubulosa Gmelin on the microbial productivity of sediments was investigated in microcosm experiments. H. tubulosa specimens were collected from a 5m deep seagrass meadow in the nearshorc waters of the Mediterranean Sea off Lacco Ameno (Island of Ischia, Gulf of Naples, Italy). Experiments were performed under different temperature regimes. Bacterial production in the incubation media and within fecal pellets increased with increasing temperature, ranging from 0.8 to 1.65 μg C 1‐1 h‐1 at 14 oC and up to 16.5 μg C ‐1‐1 h‐1 (27 oC) in the incubation media. The corresponding values within fecal pellets ranged between 3.6 and 8.5 μg C g‐l (fecal matter dry wt) h‐1 (14oC) and 30.3μg C g‐1 (fecal matter dry wt) h‐1 (27oC). Incubation experiments on the effect of feces on natural sediments indicated that fecal pellet production by H. tubulosa enhanced sediment bacterial production by about 30 %.

Two independent methods were used to estimate leaching of dissolved carbohydrates from fecal pellets. One method was based on the increase in total dissolved carbohydrates (TDCHO) in the incubation medium of the HgCl2‐treated jars, the other on the decrease in total particulate carbohydrates (TPCHO) of the fecal matter. For the experiment performed at 14 oC, we calculated a TDCHO‐leaching rate of 26.4 % d‐1 based on the increase in the HgCl2‐treated jar, while 20 % d‐1 were obtained from the decline in the TPCHO fraction of the fecal matter.
In situ Observations on Contraction Behaviour and Diel Activity of Halcampoides purpurea var. mediterranea (Cnidaria, Anthozoa) in a Marine Cave
Authors: Boero F. , Cicogna F. , Pessani D. , Pronzato R.
Published: May 2008

Abstract. The contraction behaviour of the sand‐dwelling sea anemone Halcampoides purpurea var. mediterranea was observed in situ in a cave of the Penisola Sorrentina (Gulf of Naples). The circadian rhythm of activity of two specimens, together with migrations of mysidacean swarms in and out the cave, was studied with time‐lapse photography.
Life Cycle of Liocarcinus arcuatus (Brachyura: Portunidae) in the Ría de Arousa (Galicia, NW Spain): Role of Beach and Mussel Raft Culture Areas
Authors: Freire J. , Muiño R. , Fernández L. , González‐Gurriarán E.
Published: May 2008

Abstract. The population biology of the portunid crab Liocarcinus arcuatus is analyzed over a yearly cycle in beach zones and mussel raft culture areas in the Ria de Arousa.

The breeding cycle of this species has two annual peaks, which result in two annual cohorts that are recruited in different areas. The growth rate is higher in the group settled in spring than in autumn, and, especially, in the culture areas compared with the beach zones. There are movements from the beach zones to the raft polygons related to reproductive and feeding behavior as well as growth. The role of mussel culture in the dynamics of this species is discussed.
Comparative Morphology, Ecology, and Fatty Acid Composition of West Indian Spheciospongia (Demospongea)
Authors: Vicente Vance P. , Rutzler Klaus , Carballeira Nestor M.
Published: May 2008

Abstract.The morphological variability of the common West Indian loggerhead sponge,Spheciospongia vesparium,is examined in light of the latest morphological and ecological information and new biochemical criteria, that is, composition and concentration of fatty acids. A typical and a yellow ecophenotypical form are distinguished. Comparing this species with its next relatives in the same zoogeographical region it is found thatS. othella,first described from Bermuda, cannot be maintained as a separate species.S. cuspidifera,previously misinterpreted as“Xestospongia tier‐neyi”,is confirmed as a distinct species ofSpheciospongia,whereas“Prianos” tierneyiis considered a morphological variant ofS. vesparium.
The Meiobenthos Along a Mediterranean Deep‐Sea Transect off Calvi (Corsica) and in an Adjacent Canyon
Authors: Soetaert Karline , Heip Carlo , Vincx Magda
Published: May 2008

Abstract. Meiobenthos densities (excluding hard‐shcllcd foraminifcrans) were compared along a Mediterranean deep‐sea transect off Calvi (Corsica) and in an adjacent canyon. Chloroplastic Pigment Equivalent values (CPE) provided an estimate of the amount of primary production reaching the bottom.

The stations along the transect were characterized by a low CPE content of the sediment, decreasing with increasing station depth. CPE values in the canyon were much higher, which probably resulted from import of material from the adjacent bay of Calvi. Similarly, meiobenthos densities along the transect were much lower than at comparable depths along the canyon.

Meiobenthos density was significantly and positively correlated with CPE values.

Nematodes were the most abundant taxon at all stations, followed by copepods + nauplii and the soft‐shelled foraminiferans. The meiobenthos was most abundant in the upper half centimeter. Nematode and foraminiferan densities tended to decline less rapidly with increasing depth into the sediment. Specimens belonging to the recently described phylum Loricifera, larvae of the parasitic crustacean class Tantulocarida, and fragments of an infaunal Xenophyophoria (large protozoans) are reported for the first time from the Mediterranean.
Sponges from Trawl‐Exploitable Bottoms of Ligurian and Tyrrhenian Seas: Distribution and Ecology*
Authors: Pansini M. , Musso B.
Published: May 2008

Abstract. Sponges from muddy and dctritic bottoms along the coasts of Liguria and Tuscany (Western Méditerranean) were studied to 700 m depth. The distribution of the 66 species identified was compared with depth, geographic location, as well as type of bottom and benthic community in order to determine whether a typical sponge fauna exists in these environments. The most common species (Suberites carnosus, S.ficus, Thenea muricata) are characteristic soft bottom dwellers, but the remaining sponge fauna seems to be linked to the presence of small patches of hard substrate scattered on these bottoms. As a consequence, the neighbouring hard bottom biocoenoses may remarkably affect the composition of this fauna by an export of larvae. Many species are clearly eurybathic, but most were recorded between 50 and 200 m. Type and size of the available substrate for sponge settlement and growth are apparently the most important Écological factors affecting the studied fauna.
Biometry, Bathymetric Distribution, and Reproductive Cycle of the Holothuroid Holothuria tubulosa (Echinodermata) from Mediterranean Sea grass Beds
Authors: Bulteel Patrick , Jangoux Michel , Coulon Pierre
Published: May 2008

Abstract. Holothuria tubulosa individuals were sampled regularly at three different depths (6, 19, and 33m) over a 20‐month period in a Posidonia oceanica meadow off Ischia Island (Italy). Biometrical analysis demonstrated that holothuroids have a well‐marked size‐related distribution according to depth, with the smallest individuals in the shallowest part of the meadow and the large ones in its deepest part. The observed distributions reflect the ability of H. tubulosa to grow more efficiently in areas of low water turbulence where Posidonia shoots are scattered and detrital food is more easily accessible. Recruitment takes place in the shallow meadow, and holothuroids with high reproductive potential only occur in the deep meadow. Small holothuroids (shallow individuals of similar sizes) may be either juveniles or sexually mature individuals; environmental constraints apparently restrict the growth of individuals and their gonads. There is a progressive downward migration of growing individuals when the whole population is considered, although at the level of the individual the migration occurs randomly. Accordingly, the size of a sexually mature individual is more a function of its past history in the meadow than of its real age.
Respiratory Rate and Assessment of Secondary Production in the Holothuroid Holothuria tubulosa (Echinodermata) from Mediterranean Seagrass Beds
Authors: Coulon Pierre , Jangoux Michel , Bulteel Patrick
Published: May 2008

Abstract. Respiration in Holothuria tubulosa was investigated in individuals from the Posidonia oceanica meadow off Lacco Ameno (Ischia Island, Italy). Respiratory rates increase with increasing body weight and increasing sea water temperature. Oxygen consumption of an average individual (7g dw body wall) ranges from 0.409 (14 °C) to 1.300 (26 °C) mg O2· h‐1. Data on population density, mean size of individuals, and annual sea water temperature variations allow an assessment of holothuroid production. Values of 45.65 and 13.75 kJ · m‐2· y‐1 were calculated for shallow (3 to 10 m) and deep (25 to 33 m) areas of the Posidonia meadow, respectively. Holothuroid production shows a bathymetric pattern similar to primary production of the Posidonia‐epiphytes complex and the production of Posidonia litter.
The Sponge Population of the Cabrera Archipelago (Balearic Islands): Characteristics, Distribution, and Abundance of the Most Representative Species
Authors: Uriz María Jesús , Rosell Dolors , Martín Daniel
Published: May 2008

Abstract. The abundance, distribution, and species richness of the littoral sponges (0–55 m) from the Cabrera Archipelago (Balearic Islands) were studied along light gradients from the surface to the sea bottom and from cave mouths to their inner parts. A total of 98 species (11 Calcarea and 87 Demospongiae) were recorded, 8 of which are new records for the Spanish coast.

Cluster and correspondence analyses enabled the identification of a sciophilous sponge group including three subgroups: sponges found only in semi‐dark cave habitats, a subgroup common to the coralligenous, precoralligenous, and semi‐dark cave biocoenoses, and a third subgroup exclusive to the coralligenous biocoenosis. A small number of photophilic species and other species having a wide bathymetric distribution made up another separate group. No species clusters for the different semi‐sciophilous (either fleshy or carbonate) or photophilic seaweed communities were discernible. The number of sponge species was negatively correlated with the irradiance level.
Rejection of Intracoelomic Invading Material by Leptosynapta inhaerens (Echinodermata: Holothuroida): A Process of Ecological Significance?
Authors: Jans Didier , Jangoux Michel
Published: May 2008

Abstract. The synaptid holothuroid Leptosynapta inhaerens has the ability to expel unwanted particles that enter its body cavity. Intracoelomic particles (viz. experimentally injected carmine particles) are trapped either by a coelom‐produced mucoid net or by specialized organs (the vibratile urnae) that occur in bands in some interradial areas. Whatever the trapping method, particles are incorporated into dense mucoid masses that move towards the posterior part of the body cavity, in the vicinity of the rectum. These aggregates then cross the rectal wall through rectal pores, mix with the faeces, and are eventually incorporated into the wall of the synaptid burrow. Clearance of foreign particles requires 2 to 3 days. The coelom‐cleaning system of synaptids appears to be the most effective within the class Holothuroidea, being well designed for endofaunal organisms whose walls are delicate and easily rupture.
Combined Effects of Temperature and Salinity on the Zoeal Development of the Crab Liocarcinus puber (Decapoda: Portunidae)
Authors: Nagaraj M.
Published: May 2008

Abstract. Larval development of the crab Liocarcinus puber was studied from hatching to the megalopa stage under 12 different temperature and salinity combinations, 10°C, 15°C, and 20°C (T): 20, 25, 30, and 35% (S), with a view to establishing optimum conditions for zoeal development. High larval mortalities were recorded at 10°C in all the experimental salinities, indicating the sensitivity of the larvae to low temperatures. Highest zoeal survival was obtained in the higher salinity and temperature combinations. First zoeae completed their development in all T‐S combinations tested, while successive stages showed increased sensitivity and suffered high mortalities in lower salinities at 15° and 20°C and in all salinities at 10°C. The duration of zoeal development decreased with increasing temperature, whilst the lower salinities delayed development. Q10 values did not differ much at higher salinities, with values ranging from 1.5 to 2.6.
Diurnal Variation in Pigment Content in Porphyra laciniata and Chondrus crispus and its Relation to the Diurnal Changes of Underwater Light Quality and Quantity
Authors: López‐Figueroa Félix
Published: May 2008

Abstract. Short‐term diurnal changes in the pigment content of two red algae, Porphyra laciniata and Chondrus crispus, in their natural environment (Helgoland, North Sea) were detected. Simultaneously, diurnal variations in underwater light quality and quantity were analyzed. A relation between rapid changes in pigment content at twilight and drastic changes in certain wavelength bands: red: far‐red, green: red, and blue: red was observed. Through these ratios, which were detected by various photoreceptor systems, the algae were able to modulate the pigment content during the course of the day.

Diurnal changes in the total photosynthetic pigment (chlorophyll a and biliprotein) contents and pigment ratios of the red algae Porphyra laciniata growing at 0.5 m and 3.5 m and Chondrus crispus at 2‐2.5 m under natural conditions in Helgoland (North Sea) in July 1990 have been observed.

The underwater light quality and quantity, the attenuation coefficient (K) in some wavebands, and the ratios: red: far‐red (R: FR), green: red (G: R), and blue: red (B: R) throughout the day and at different depths (0.5, 1, 1.5, 2.5, and 3.5 m) were measured at the same time as the pigment contents. At twilight, rapid quality changes were observed. Directly after this period, major pigment changes in Porphyra and Chondrus were detected.

Drastic changes in the pigment content in Porphyra laciniata at twilight, immediately after this period, and after noon were observed. The pigment content of plants growing at 0.5 m and plants transplanted to 3.5m were significantly different (P <0.05). Porphyra at 3.5m had higher PE/PC and PE/Chl a ratios than at 0.5 m. The maximum biliprotein level was observed immediately after noon. The algae growing at deeper levels produced more biliprotein in response to a simultaneous decrease in light intensity and an increase in the G: R ratio. In addition, at dawn, an “inverse chromatic adaptation” was observed, since PE/PC and PE/Chl a ratios during this period decreased when G/R increased.

In Chondrus crispus, diurnal Chl a variations showed a reverse pattern in relation to biliprotein variations: the biliprotein content increased during daylight, while Chl a decreased. Maximum PE and PC was produced after noon. The biliprotein: Chl a ratio showed a clear circadian rhythm.

The changes in R: FR, G: R, and B: R ratios are proposed as being “photomorphogenic signals” which control the pigment content in algae. Because R: FR and G: R ratios increase linearly with depth, the detection of light quantity changes through these ratios is proposed.
Proximate Constituents in the Sea‐grasses Zostera marina and Z. noltii in Ireland: Seasonal Changes and the Effect of Blade Removal
Authors: Dawes Clinton J. , Guiry Michael D.
Published: May 2008

Abstract. Zostera marina L. from the lower intertidal of Galway Bay and Dingle Harbour, Ireland, showed new blade growth in the winter and spring months, a period of high protein levels (to 22%). Soluble carbohydrates (28–49%) were highest in the rhizome in November and after blade production in May. During the period of blade production or blade removal by means of cropping, soluble carbohydrate levels decreased in the rhizome indicating a storage function. The diminutive upper intertidal species, Z. noltii (Hornem.) Reichb. from Dungarvan Harbour, Ireland, also had highest protein levels in its blades in November and May, but the level of soluble carbohydrates in its rhizome was low compared with the larger species. The study indicates that Z. marina, being a perennial with a rhizome that functions as a storage organ, shows “K” type ecological strategies compared with the smaller species.

Protein as well as soluble and insoluble carbohydrate and lipid levels of the blades, rhizomes, and roots of Zostera marina collected seasonally from Galway Bay and Dingle Harbour, Ireland, were similar to published data for the species and to data of other seagrasses. Protein levels were high in the blades and highest during spring blade growth. Soluble carbohydrate was highest in the rhizome segments during the winter, decreasing during spring blade production or when the blades were cropped. In contrast, the diminutive species Z. noltii did not show a seasonal rise in soluble carbohydrate and its blades tended to have high levels of protein in both fall and spring collections. The storage of soluble carbohydrate and long‐term survival of Z. marina suggests that this species is more a “K” strategist, while Z. noltii appears to be an opportunistic species.
Cotylorhiza tuberculata (Cnidaria: Scyphozoa) ‐ Life History of a Stationary Population
Authors: Kikinger Reinhard
Published: May 2008

Abstract. The life history of a stationary population of Cotylorhiza tuberculata (Maori, 1778) was studied on the Ionian island of Lefkada, Greece, in 1980 and 1981. Occurrence, growth, maturation, and aging of medusae indicated an annual life cycle of this rhizostomous jellyfish. Ephyrae are liberated during strobilation peaks in spring and summer; exceptionally high growth rates lead to medusa diameters of up to 40 cm after six months. Due to symbiotic zooxanthellae the medusae are potentially autotrophic; P: R values ranged from 0.36 to 1.17. The gonochoristic medusae mature during summer; a sexual dimorphism is evident by brood‐carrying filaments in females. The life span of the medusae is about half a year, while scyphistomae are potentially perennial. The observed annual metagenetic cycle is interpreted as a life history adaptation to a highly seasonal environment.

In the Ionian Sea the metagenetic cycle of a stationary bay population of Cotylorhiza tuberculata is annual. Strobilation occurs during spring and summer. Rapid growth leads to medusa diameters of up to 40 cm within 6 months. The medusae are potentially autotrophic due to their zooxanthellae. The gonochoristic medusae exhibit sexual dimorphism, and spermatozoa are released as spermatozeugmata. Fertilization is internal, with embryogenesis taking place inside the female moutharm canals. The life span of the medusae is limited by deterioration of somatic tissue to about half a year; no medusae of the bay population survive winter. The planula is the only stage within the metagenetic cycle without zooxanthellae, and infection with algal symbionts occurs in scyphistomae. In the laboratory, the potentially perennial scyphistomae preferentially colonize the underside of hard substrates and reproduce by lateral budding; strobilation is monodiscous.
Reproductive Cycles of the Ascidians Microcosmus sabatieri and Halocynthia papillosa in the Northwestern Mediterranean
Authors: Becerro M. A. , Turon X.
Published: May 2008

Abstract. The reproductive cycles of Microcosmus sabatieri Roule and Halocynthia papillosa (Linnaeus) (Ascidiacea, Pyuridae) were investigated by means of histological observations of the gonads and gonad index measurements on monthly samples from Northeast Spanish coast populations during 1985. Both species are simultaneous hermaphrodites, and the spawning season lasts for two to three months ‐ between September and November ‐ after the period of highest water‐temperatures in the area. The evolution of the gonads during the whole cycle is markedly different in both species. Spawning time is extended towards summer in H. papillosa and towards winter in M. sabatieri.

The parameters studied in H. papillosa and M. sabatieri indicate a single spawning season per year in the area studied. Both species are simultaneous hermaphrodites, and gamete release occurred after the period of highest seawater temperatures, with a maximum in September‐October for H. papillosa and in October‐November for M. sabatieri. Moreover, the release is noticeably more rapid in H. papillosa.

Mean oocyte diameter and gonad index show a good correlation. The values of the latter were almost twice as high in H. papillosa than in M. sabatieri. Since no development of nutritional tissue has been observed in histological sections, this can reasonably be interpreted as a higher investment in gamete production in H. papillosa.

Rapid buildup of the gonad, gradual release of gametes, and low gonad indices occur in M. sabatieri, whereas gradual buildup, rapid release, and higher gonad indices are displayed by H. papillosa. This indicates different reproductive behavior in these species, a conclusion which is confirmed by statistical analyses.
Population Parameters, Life Cycle, and Feeding ofMysidium columbiae(Zimmer) in the Waters Surrounding a Belizian Mangrove Cay
Authors: Modlin Richard F.
Published: May 2008

Abstract.The ecology of tropicalMysidaceais poorly known.Mysidium columbiae(Zimmer), because of its ubiquitous distribution in the tropical western Atlantic and the information available on its aggregative behavior, is an ideal subject of study to reconcile aspects of this problem. Information and data were obtained on abundance, population size, shoal/school structure, fecundity, development, and feeding of aM. columbiaepopulation inhabiting waters surrounding Twin Cays, a mangrove archipelago in Belize. Although reproduction was continuous and proportions of life stages within shoals remained relatively constant throughout the year, population size decreased by an order of magnitude from summer to winter. Embryonic development averaged 4.7 days, with postlarvae being released near the surface before dawn. Aquarium experiments suggested that olfaction may be more sensitive than vision, although both senses were used to locate food. This species is a detritivore, but gut contents suggested that it may also be a predator.
The Distribution of Polychaetes Along Environmental Gradients: An Example from the Or betel I o Lagoon, Italy
Authors: Lardicci C. , Abbiati M. , Crema R. , Morri C. , Bianchi C. N. , Castelli A.
Published: May 2008

Abstract. Biological zonation in brackish habitats is usually related to the gradients of several factors, of which salinity is often taken as the most important. In contrast, recent papers, mainly on Mediterranean lagoons, have emphasized the role of other factors such as water movement and trophic status. In this paper, the distribution of polychaetes in the Orbetello lagoon (a poly‐hyperhaline pond on the northern Tyrrhenian coast) is compared with the gradients of a number of environmental parameters. Polychaete distribution turned out to be under the control of a variety of highly interrelated factors. The study of biotic zonation as a function of a single driving factor is thus overly simplistic even when dealing with ‘simple’ environments, as lagoons are often defined. Several factors and their synergistic effects must always be taken into account.

A total of 79 species was collected from 13 sites in the Orbetello lagoon, comprising both brackish‐water and marine species as well as a large number of species typical of organically enriched habitats. Through correspondence analysis, three major polychaete assemblages were recognized, linked to three different zones of the lagoon: 1) the channels connecting the lagoon to the sea; 2) the western lagoon; 3) the eastern lagoon (including a small part of the western lagoon situated near the town of Orbetello). Such a zonation was shown ‐ by Trend Surface and linear correlation analyses ‐ to be consistent with the spatial trends of a number of environmental parameters such as vivification/confinement, water movement, dissolved oxygen, poikilohalinity, and poikilothermy (in the order of importance); in contrast, salinity (minimal values), sediment grain size, and primary productivity showed little or no relation to polychaete distribution. However, almost all environmental parameters were significantly correlated with each other, thus making it impossible to identify the principal factor. This demonstrates that biotic zonation cannot be explained as the resultant of the action of a single driving factor (e. g., salinity or confinement), even in environments which are usually considered to be relatively simple from a synecological point of view, such as brackish habitats. Both the synergism among the various abiotic factors and the influence of biotic interactions must always be taken into account.
Spawning and Dispersal in Ciona intestinalis (L.)
Authors: Svane Ib , Havenhand Jon N.
Published: May 2008

Abstract. Oviparous solitary ascidians, such as Ciona intestinalis (L.), generally spawn freely into the water‐column where the eggs are fertilized and develop into free‐swimming non‐feeding larvae. In the laboratory, both spawning and settlement are controlled by light. It has been suggested that both spawning and development time are synchronized so that larval settlement takes place under optimal light conditions in the middle of the day when larvae are best able to locate shaded habitats. Our observations of field populations, however, have shown that Ciona may spawn and settle at any time of the day. Freely spawned eggs, which are negatively buoyant and slightly adhesive, may become attached to any available substratum. Ova can also be released in mucus strings which are particularly adhesive and will readily adhere to adult Ciona and other surfaces. In all cases, fertilization and development proceed normally. Laboratory investigations have shown that newly hatched larvae may either escape to the plankton or be retained in the mucus string until settlement. Thus, the dense aggregations of both adults and newly settled Ciona which are commonly observed in the field could be explained by abbreviated dispersal due to mucus string spawning and epibenthic retention of eggs.

In the field, Ciona intestinalis embryos at different developmental stages are found simultaneously, indicating that spawning is not confined to a specific time of day. Free eggs are negatively buoyant and slightly adhesive. Eggs are spawned in mucus strings, where fertilization and development takes place. Such strings are retained epibenthically. Settlement and subsequent metamorphosis takes place in the mucus strings, but in the laboratory 40 to 60 % of the larvae escape to the plankton. The aggregation of both adult and juvenile Ciona observed in the field can be explained by mucus string spawning and epibenthic retention of eggs.
Microbial Shell Destruction in Deep‐Sea Mussels, Florida Escarpment
Authors: Hook James E. , Golubic Stjepko
Published: May 2008

Abstract.Two distinctive patterns of microbial destruction of mineral shell in mussels from the Florida Escarpment (3266 m water depth) are described. One pattern follows a surfacial selective removal of intercrystalline organic matrix creating caries‐like pits. Pitting of the shell resembles spreading bacterial colonies and results in substantial thinning of the original shell. The second pattern consists of an extensive system of sacs with branched and tapered extensions penetrating deep into the shell. Both activities are carried out by unknown microbial agents on live mussels, as evidenced by the presence of repair nacre, which often underlies effected areas. Shell destruction is primarily biological, providing conditions for enhanced chemical dissolution of the mineral shell.

Damage and removal of the protective periostracum layer of deep‐sea mussels by various eukaryotic and prokaryotic microorganisms (Hook& Golubic, 1988, 1990, 1992) exposes the mineral portion of the shell to microbial destruction. This biogenic destruction exceeds the rates of inorganic carbonate dissolution in the area of study. Two types of destructive agents attack the shells of live mussels. The first type forms shallow caries along the interface between periostracum and the mineral shell, primarily attacking intercrystalline organic matrix. The second type represents boring microorganisms, morphologically similar to chytrids, that penetrate and permeate the entire mineral portion of the shell. These activities significantly weaken the shell structure and increase its internal porosity.
Distribution and Abundance of Calyco‐phores (Siphonophora, Calycophorae) in the Mediterranean and Adriatic Sea
Authors: Gamulin Tomo , Kršinic Frano
Published: May 2008

Abstract. The paper presents data on the distribution of calycophores in the open Mediterranean waters based on samples collected during the R/V “Atlantis II” cruise in May‐June 1969, as well as the first data on the distribution and quantity of nectophores and gonophores in the coastal and open Adriatic waters. The following species were numerically important in the eastern Mediterranean: Eudoxoides spiralis, Bassia bassensis, Sulculeoaria chuni, Lensia campanella, and Diphyes dispar. In the western part of the study area, however, calycophores were found in low numbers. The presence of the immigrating Atlantic forms, Muggiaea atlantica and Lensia subtiloides, was also registered. Among 22 Adriatic calycophores, numerically important were: Muggiaea kochi, Lensia subtilis, Sphaeronectes gracilis, and S. irregularis. Other species were rarely found and mainly distributed in the Otranto Strait and the Southern Adriatic Pit.

This paper presents data on calycophores found in samples taken during the R/S “Atlantis II” cruise from Rhodos to Gibraltar in May–June 1969, the seasonal cruises along the eastern Adriatic coast in 1973/74, and those in the open Adriatic waters in 1974–1976.

In the eastern Mediterranean the species E. spiralis, B. bassensis, S. chuni, L. campanella, and D. dispar were numerically important. In contrast, calycophores were not as abundant in the western Mediterranean. However, the presence of the immigrating Atlantic forms M. atlantica and L. subtiloides was registered.

In the Adriatic Sea as many 22 species were found; the most widespread and numerically important were M. kochi, L. subtilis, S. gracilis, and S. irregularis.

The dominant species M. kochi contributed from 57 to 87% to the total number of nectophores. Other species were rarely present or of smaller quantitative importance and were mainly distributed in the Otranto Strait and the South Adriatic Pit; north of the Ancona‐Losinj profile these forms were not registered at all.

A statistically significant positive correlation between the quantity of nectophores and sexual persons of gonophores was determined. Gonophores were more abundant than nectophores throughout the study period. They were especially numerous during the warmer months.
Seasonality and Reproductive Phenology of Algae Inhabiting Littoral Pools in the Western Mediterranean
Authors: Benedetti‐Cecchi Lisandro , Cinelli Francesco
Published: May 2008

Abstract.This paper reports on a one‐year investigation carried out inCystoseira‐dominated littoral pools from the west coast of Italy.

The seasonal occurrence of the algae and their reproductive characteristics are described. The importance of environmental factors and recruitment processes in determining algal distribution and abundance are also discussed.

Algal seasonality and reproductive phenology was studied inCystoseira‐dominated tidepools from July 1989 to July 1990. Algae were collected monthly, sorted to species, and checked for reproductive structures. The data were analyzed by means of multivariate techniques (PCA and cluster analysis).

Seasonal fluctuations were more evident for annual and ephemeral algae, with peaks in abundance during the summer, while perennial algae showed a slight decline in winter because of storms. Among the 66 taxa recorded, 26 algae were found to be fertile at least once during the study year. These species showed a considerable variation in the seasonal periodicity of reproduction.

We suggest that the seasonal patterns of the assemblage were mainly regulated by physical factors, because herbivores were virtually absent in the investigated pools. Moreover, the periodicity of algal reproduction could also have an effect. Since the pool of propagules available to colonize newly disturbed areas changes through time according to the reproductive phenology of the algae and varies so widely, early successional sequences may be governed by the disturbance regime and propagule availability.
A Simulation Model of a Deep Meiobenthic Compartment: A Preliminary Approach
Authors: de Bovee F. , Labat J. Ph.
Published: May 2008

Abstract. On the basis of data obtained during the ECOMARGE programme and during an annual survey of a deep station (910 m), a first attempt at modelling the carbon flux through a simplified benthic system is presented. Three compartments are simulated: organic matter, bacteria, nematodes. Several hypotheses are proposed by the present simulation: constant or seasonal input of organic matter, intra‐compartmental control or lack thereof. The pulses related to the seasonal input of organic matter and to the internal kinetics of the system are described. Nine to 11 mg C · m‐2· d‐1 are necessary to equilibrate the carbon budget of this simplified deep‐sea benthic system.

A simulation model is used to estimate the importance of energy transfers which could equilibrate the needs of a deep nematode community in the course of time.

The observed values for the compartments are obtained from the annual survey of a deep station (910m) of the ECOMARGE programme. Surface sediment organic matter concentrations ranged from 0.50 % to 0.56 % sediment dry weight (or 67,000 mg C · m‐2 to 75,000 mg C · m‐2, respectively), for a mean near‐bottom flux input of 33g C · m‐2· a‐1 (90mg · m‐2· d‐1). The mean organismal biomass approximated to 30 mg C · m‐2 for the bacteria and 37 mg C · m‐2 for the meiofauna.

In the simulations, when 9–11% of the input flux are used by the system (9–10 mg C · m‐2· d‐1), the meiofauna compartment is maintained close to the osberved level, while bacterial biomass (9 mg C · m‐2) is lower than the observed value. At lower rates (<8%), the meiobenthic compartment disappears, at higher rates (> 12%) the simulated biomasses show unrealistic values. With a seasonal input flux, the periods of the meiofauna biomass pulses correspond well with the observed data. The mean time lag between the maximum values of the organic matter input and the simulated maximum biomass is 60 days, slightly smaller than the observed value.
Ecology of the Symbiotic Coral Cladocora caespitosa (L.) (Faviidae, Scleractinia) in the Bay of Piran (Adriatic Sea): I. Distribution and Biometry
Authors: Schiller Christian
Published: May 2008

Abstract. Cladocora caespitosa is a relatively common, colonial, symbiotic, scleractinian coral in the Mediterranean Sea. It inhabits a wide ecological range: hard and soft bottoms, shallow waters or depths to about 50m, calm water or sites exposed to strong currents and wave action. The present study compares the distribution of this coral at two sites, one shallow (3m — wave exposed) and one deeper (12m — soft bottom).

Different parameters including dry weight, volume, and skeletal growth rates were investigated. The polyp biomass, carbon content, and overall area of fully expanded polyps were also measured. Equations are given for the relationship of skeleton diameter to polyp tissue dry weight as well as skeleton diameter to the possible filter area of fully expanded polyps.

C. caespitosa harbors a rich community of vagile and sessile organisms within the skeleton. The cryptofauna was sorted to higher taxonomic levels and their biomass determined. Several highly significant linear relationship were found between skeleton dry weight, volume and cryptofauna biomass. Thus, the determination of colony volume allows the prediction of cryptofauna biomass.

The interstitial space is dominated by sponges ‐ many of them borers ‐ which erode the corallites close to the living tissue until they break off from the colony. At the deeper sampling site, 26% of all colonies are smaller than 2 cm and 48% are smaller than 5 cm. The fragmentation process is discussed with respect to reproduction.
Fluctuations and Variations in Coastal Marine Environments
Authors: Boero Ferdinando
Published: May 2008

Abstract. The manifold aspects of variability of coastal marine ecosystems are reviewed, with special reference to the response of species and communities. Fluctuations are defined as recurrent modifications in community structure, for instance due to seasonality, whereas variations are defined as changes permanently leading from a given community to a different one. Both patterns are described and linked to the interaction between life history traits and environmental factors. Resting stages are proposed to play a still underestimated role in the dynamics of coastal communities, especially for plankton. Rare species are considered as an essential constant of communities, being the source of potential variation and alternance in the contribution to the standing biomass.
Interaction Between Macrophytobenthic Groups on the Sublittoral Belt of a Greek Island
Authors: Diappoulis Aristidis , Conides Alexis , Koussouris Theodore
Published: May 2008

Abstract. The interrelationships between the main phytobenthic groups of Chlorophyceae, Phaeophyceae, and Rhodophyceae around Milos Island, Central Aegean Sea, were studied using standard ecological and mathematical methods. The analysis was based on seasonal sampling of 114 different macrophytobenthic species.

The employed ecological indices revealed that the sampling areas located on the north, south, and east side of Milos Island show similar annual fluctuations in abundance and species diversity. The resemblance was particularly high between all stations in October‐February, between south and east stations during May, and between north and east stations during July.

Additionally, an annual cycle of group interaction with regard to species diversity and abundance exists between the Chlorophyceae, Rhodophyceae, and Phaeophyceae. The Rhodophyceae are the most abundant and dominant group throughout the year, showing percentages in the samples higher than 70% in all sampling areas.
Growth Dynamics, Production, and Nutrient Status of the Seagrass Cymodocea nodosa in a Mediterranean Semi‐Estuarine Environment
Authors: Pérez Marta , Romero Javier
Published: May 2008

Abstract. Cymodocea nodosa is a relatively small seagrass species which is common in the Mediterranean. An intensive survey on its growth and production was carried out in a dense, monospecific stand located in a semi‐estuarine embayment. Data on leaf appearance and growth, shoot recruitment and death, rhizome growth, above‐ and belowground biomass, and nutrient content in the different parts of the plant were obtained over 2 years. All these variables showed a clear seasonality. In general, maximum growth and production occurred in early summer (July), and maximum biomass was reached between July and September. Biomass, shoot density, growth and production showed clear minima in winter.
Response of Sublittoral Hard Substrate Invertebrates to Estuarine Sedimentation in the Outer Harbour of Bilbao (N. Spain)
Authors: Salinas J. I. Saiz , Urdangarin I. Isasi
Published: May 2008

Abstract.Four sampling stations with relatively similar hard‐bottom substrates were investigated to determine if there were differences between the sublittoral invertebrates near the Nervión River mouth (N. Spain) and those closer to the open sea, and if faunal differences could be attributed to the impact of estuarine sedimentation. Four 100 m long transects were surveyed using photographic and quadrat techniques, yielding data on percentage cover of all invertebrates from 136 visual inventories. Data were analysed to determine whether any community response to sedimentation was evident. Ordination (multidimensional scaling) and classification (group‐average clustering) based on Bray‐Curtisdissimilarity measures separated the stations at three levels based on the different faunal assemblages. The analysis suggests the presence of a gradient along the estuary discharge, mainly affecting the east side of the outer part of Bilbao harbour, since the estuarine plume flows to the east. The influence can be expressed in terms of retrogression of the variety of species and disappearance of the algal fraction, which is progressively replaced by an animal assemblage of tolerant and opportunistic suspension feeders. Several ‘indicator’ species were identified on the basis of strong density differences between sites; matrix correlations presented here were found to produce complementary and consistent results. The role of estuarine sedimentation disturbance as the main factor controlling subtidal assemblages in outer Bilbao harbour is discussed.
Polychaete Depth Distribution in a Posidonia oceanica Bed (Rhizome and Matte Strata) and Neighbouring Soft and Hard Bottoms
Authors: Somaschini A. , Gravina M. F. , Ardizzone G. D.
Published: May 2008

Abstract. The study was carried out in a Posidonia oceanica bed and in the neighbouring sandy and rocky bottoms, at Ponza Island (Central Tyrrhenian Sea), in order to investigate the distributional pattern of the polychaete community at different depths. A total of 15232 individuals of polychaetes belonging to 218 species was collected and three new species of Syllidae were found. The polychaete community of the matte can be clearly distinguished from the neighbouring communities; this is due to the high species richness in Posidonia, which is related to the heterogeneity of the biotope. In the Posidonia bed the shallow stations (1 m and 5 m depth) were the richest in terms of species numbers and individuals due to the high shoot density of the seagrass bed. In the shallow waters polychaete community structure changed according to the different exposure to water movement. Rocky bottom species, which preferentially inhabit crevices, were more abundant in the matte exposed to water movement (5–10 m depth). In contrast, soft‐bottom species were more abundant in the sheltered zone (1 m depth) as well as in the deeper zone due to the reduction of the Posidonia bed.
The Structure of Coral Communities at Hurghada in the Northern Red Sea
Authors: Riegl Bernhard , Velimirov Branko
Published: May 2008

Abstract. The community structure of hard and soft corals, with an emphasis on hard corals, was determined by means of line‐transects on 9 on‐and off‐shore reefs of different type and different wave exposure in the Northern Red Sea near Hurghada in Egypt. Coral communities were found to differentiate along a horizontal wind‐ and wave‐exposure gradient. Exposed communities were dominated by Acropora species, sheltered communities by Porites species, and semi‐exposed communities by Millepora species. Also, vertical within‐reef zonations following a depth gradient were observed; these were unique for each exposure‐determined community type. Average transect diversity was highest on semi‐exposed reefs, lowest on sheltered reefs. Reef slopes were more diverse than other reef zones. The observed community structure was compared with data from the literature, and widely distributed, roughly comparable hard and soft coral communities were identified.