Struttura dei popolamenti meiobentonici nella zona intertidale dell'Alto Adriatico a differenti gradi di antropizzazione

The present work is part of the European project THESEUS (Innovative technologies for safer Europeans coasts in a changing climate). The main goals are to provide adequate integrated methodologies for strategic planning of sustainable coastal defence. The present study investigates the structure and composition of meiobenthonic populations of the intertidal zone in four beaches along the Northern Adriatic coast of Emilia Romagna: Lido di Spina, Bellocchio, Lido di Dante e Cervia. The four sites are different for the level of human impacts and for the different management interventions against coastal erosion. The analysis of biotic and abiotic variables revealed different responses due mainly to site-specific characteristics of the investigated sites, in particular as regards the site of Bellocchio. The growing interest in ecosystems of sandy beaches has recently highlighted the importance of the ecological role of meiofauna, emphasizing the need to develop studies aimed to conservation as well as to the use of these organisms as descriptors of the environmental status. The present study showed that the response of the organisms of meiofauna was highly sensitive to the specific environmental conditions of the four sites considered. Therefore it appears to be possible to consider the response of meiofauna to environmental and anthropogenic stressors as supplementary information to the responses of macrobenthic communities, which have been, until now, widely recognized and used as syncretic indicators of the ecosystem status.

Analysis of the relationships between Spartina maritima and nutrient enrichment in North Adriatic salt marshes

Salt marshes are coastal ecosystem in the upper intertidal zone between internal water and sea and are widely spread throughout Italy, from Friuli Venezia Giulia, in the North, to Sicily, in the South. These delicate environments are threatened by eutrophication, habitat conversion (for land reclaiming or agriculture) and climate change impacts such as sea level rise. The objectives of my thesis were to: 1) analyse the distribution and biomass of the perennial native cordgrass Spartina maritima (one of the most relevant foundation species in the low intertidal saltmarsh vegetation in the study region) at 7 sites along the Northern Adriatic coast and relate it to critical environmental parameters and 2) to carry out a nutrient manipulation experiment to detect nutrient enrichment effects on S. maritima biomass and vegetation characteristics. The survey showed significant differences among sites in biological response variables - i.e., live belowground, live aboveground biomass, above:belowground (R:S) biomass ratio, % cover, average height and stem density – which were mainly related to differences in nitrate, nitrite and phosphate contents in surface water. Preliminary results from the experiment (which is still ongoing) showed so far no significant effects of nutrient enrichment on live aboveground and belowground biomass, R:S ratio, leaf %Carbon, average height, stem density and random shoot height; however, a significantly higher (P=0.018) increase in leaf %Nitrogen content in treated plots indicated that nutrient uptake had occurred.

Biogeochemistry (speciation and isotopes of S and C) in bottom sediments, water and bacterial mats from the White Sea

This publication presents results of microbiological and biogeochemical studies in the White Sea. Material was obtained during a series of expeditions in 1999-2002. The studies were carried out in the open part of the White Sea, in the Onega, Dvina and Kandalaksha Bays, as well as in the intertidal zone of the Kandalaksha Bay. Quantitative characteristics of activity of microbial processes in waters and bottom sediments of the White Sea were obtained. The total number of bacteria was equal to 150000-800000 cells/ml, and intensity of dark CO2 assimilation was equal to 0.9-17 µg C/l/day. Bacterial sulfate reduction was equal to 3-150 mg S/m**2/day, and methane formation and oxidation was equal to 13-6840 and 20-14650 µl CH4/m**2/day, respectively. Extremely high values of intensity of all principal microbial processes were found in intertidal sediments rich in organic matter: under decomposing macrophytes, in local pits at the lower intertidal boundary, and in the mouth of a freshwater brook. Average hydrogen sulfide production in highly productive intertidal sediments was 1950-4300 mg S/m**2/day, methane production was 0.5-8.7 ml CH4/m**2/day, and intensity of methane oxidation was up to 17.5 ml CH4/m**2/day. Calculations performed with account for areas occupied by microlandscapes of increased productivity showed that diurnal production of H2S and CH4 per 1 km**2 of the intertidal zone (August) was estimated as 60.8-202 kg S/km**2/day and 192-300 l CH4/km**2/day, respectively.

Community structure and biodiversity in marine benthic communities during experiments, 2011

A mesocosm experiment was conducted to quantify the effects of reduced pH and elevated temperature on an intact marine invertebrate community. Standardised faunal communities, collected from the extreme low intertidal zone using artificial substrate units, were exposed to one of eight nominal treatments (four pH levels: 8.0, 7.7, 7.3 and 6.7, crossed with two temperature levels: 12 and 16°C). After 60 days exposure communities showed significant changes in structure and lower diversity in response to reduced pH. The response to temperature was more complex. At higher pH levels (8.0 and 7.7) elevated temperature treatments contained higher species abundances and diversity than the lower temperature treatments. In contrast, at lower pH levels (7.3 and 6.7), elevated temperature treatments had lower species abundances and diversity than lower temperature treatments. The species losses responsible for these changes in community structure and diversity were not randomly distributed across the different phyla examined. Molluscs showed the greatest reduction in abundance and diversity in response to low pH and elevated temperature, whilst annelid abundance and diversity was mostly unaffected by low pH and was higher at the elevated temperature. The arthropod response was between these two extremes with moderately reduced abundance and diversity at low pH and elevated temperature. Nematode abundance increased in response to low pH and elevated temperature, probably due to the reduction of ecological constraints, such as predation and competition, caused by a decrease in macrofaunal abundance. This community-based mesocosm study supports previous suggestions, based on observations of direct physiological impacts, that ocean acidification induced changes in marine biodiversity will be driven by differential vulnerability within and between different taxonomical groups. This study also illustrates the importance of considering indirect effects that occur within multispecies assemblages when attempting to predict the consequences of ocean acidification and global warming on marine communities.

Seawater carbonate chemistry and physiological responses of three temperate coralline algae in a laboratory experiment

Coralline algae are major calcifiers of significant ecological importance in marine habitats but are among the most sensitive calcifying organisms to ocean acidification. The elevated pCO2 effects were examined in three coralline algal species living in contrasting habitats from intertidal to subtidal zones on the north-western coast of Brittany, France: (i) Corallina elongata, a branched alga found in tidal rock pools, (ii) Lithophyllum incrustans, a crustose coralline alga from the low intertidal zone, and (iii) Lithothamnion corallioides (maerl), a free-living form inhabiting the subtidal zone. Metabolic rates were assessed on specimens grown for one month at varying pCO2: 380 (current pCO2), 550, 750 and 1000 µatm (elevated pCO2). There was no pCO2 effect on gross production in C. elongata and L. incrustans but L. incrustans respiration strongly increased with elevated pCO2. L. corallioides gross production slightly increased at 1000 µatm, while respiration remained unaffected. Calcification rates decreased with pCO2 in L. incrustans (both in the light and dark) and L. corallioides (only in the light), while C. elongata calcification was unaffected. This was consistent with the lower skeletal mMg/Ca ratio of C. elongata (0.17) relative to the two other species (0.20). L. incrustans had a higher occurrence of bleaching that increased with increasing pCO2. pCO2 could indirectly impact this coralline species physiology making them more sensitive to other stresses such as diseases or pathogens. These results underlined that the physiological response of coralline algae to near-future ocean acidification is species-specific and that species experiencing naturally strong pH variations were not necessarily more resistant to elevated pCO2 than species from more stable environment.

A theoretical study on the formation of iodine oxide aggregates and monohydrates

Biotic and abiotic emissions of molecular iodine and iodocarbons from the sea or the ice surface and the intertidal zone to the coastal/polar marine boundary layer lead to the formation of iodine oxides, which subsequently nucleate forming iodine oxide particles (IOPs). Although the link between coastal iodine emissions and ultrafine aerosol bursts is well established, the details of the nucleation mechanism have not yet been elucidated. In this paper, results of a theoretical study of a range of potentially relevant aggregation reactions of different iodine oxides, as well as complexation with water molecules, are reported. Thermochemical properties of these reactions are obtained from high level ab initio correlated calculations including spin–orbit corrections. The results show that the nucleation path most likely proceeds through dimerisation of I2O4. It is also shown that water can hinder gas-to-particle conversion to some extent, although complexation with key iodine oxides does not remove enough of these to stop IOP formation. A consistent picture of this process emerges from the theoretical study presented here and the findings of a new laboratory study reported in the accompanying paper (Gomez Martin et al., 2013).

Propagation and use of Spartina alterniflora for shoreline erosion abatement /

Experimental plantings to stabilize eroding shorelines in Bogue Sound in 1974 were successful. Better stands were produced on sites subject to severe wave stress by reducing transplant spacing to 1.5 to 2 feet apart. Rhizomes without well-developed culms attached were worthless as propagules within the intertidal zone. Seeding was unsuccessful due to exposure to excessive wave energy.

Variation in mangrove forest structure and sediment characteristics in Bocas del Toro, Panama

Mangrove forest structure and sediment characteristics were examined in the extensive mangroves of Bocas del Toro, Republic of Panama. Forest structure was characterized to determine if spatial vegetation patterns were repeated over the Bocas del Toro landscape. Using a series of permanent plots and transects we found that the forests of Bocas del Toro were dominated by Rhizophora maugle with very few individuals of Avicennia germinans and Laguncularia racemosa. Despite this low species diversity, there was large variation in forest structure and in edaphic conditions (salinity, concentration of available phosphorus, Eh and sulphide concentration). Aboveground biomass varied 20-fold, from 6.8 Mg ha(-1) in dwarf forests to 194.3 Mg ha(-1) in the forests fringing the land. But variation in forest structure was predictable across the intertidal zone. There was a strong tree height gradient from seaward fringe (mean tree height 3.9 m), decreasing in stature in the interior dwarf forests (mean tree height 0.7 m), and increasing in stature in forests adjacent to the terrestrial forest (mean tree height 4.1 m). The predictable variation in forest structure emerges due to the complex interactions among edaphic and plant factors. Identifying predictable patterns in forest structure will aid in scaling up the ecosystem services provided by mangrove forests in coastal landscapes.

Are mangroves in the tropical Atlantic ripe for invasion? Exotic mangrove trees in the forests of South Florida

Abstract Two species of mangrove trees of Indo- Pacific origin have naturalized in tropical Atlantic mangrove forests in South Florida after they were planted and nurtured in botanic gardens. Two Bruguiera gymnorrhiza trees that were planted in the intertidal zone in 1940 have given rise to a population of at least 86 trees growing interspersed with native mangrove species Rhizophora mangle, Avicennia germinans and Laguncularia racemosa along 100 m of shoreline; the population is expanding at a rate of 5.6% year-1. Molecular genetic analyses confirm very low genetic diversity, as expected from a population founded by two individuals. The maximumnumber of alleles at any locus was three, and we measured reduced heterozygosity compared to native-range populations. Lumnitzera racemosa was introduced multiple times during the 1960s and 1970s, it has spread rapidly into a forest composed of native R. mangle, A. germinans, Laguncularia racemosa and Conocarpus erectus and now occupies 60,500 m2 of mangrove forest with stem densities of 24,735 ha-1. We estimate the population growth rate of Lumnitzera racemosa to be between 17 and 23% year-1. Populations of both species of naturalized mangroves are dominated by young individuals. Given the long life and water-dispersed nature of propagules of the two exotic species, it is likely that they have spread beyond our survey area. We argue that the species-depauperate nature of tropical Atlantic mangrove forests and close taxonomic relatives in the more species-rich Indo-Pacific region result in the susceptibility of tropical Atlantic mangrove forests to invasion by Indo-Pacific mangrove species.

Are mangroves in the tropical Atlantic ripe for invasion? Exotic mangrove trees in the forests of South Florida

Two species of mangrove trees of Indo- Pacific origin have naturalized in tropical Atlantic mangrove forests in South Florida after they were planted and nurtured in botanic gardens. Two Bruguiera gymnorrhiza trees that were planted in the intertidal zone in 1940 have given rise to a population of at least 86 trees growing interspersed with native mangrove species Rhizophora mangle, Avicennia germinans and Laguncularia racemosa along 100 m of shoreline; the population is expanding at a rate of 5.6% year-1. Molecular genetic analyses confirm very low genetic diversity, as expected from a population founded by two individuals. The maximumnumber of alleles at any locus was three, and we measured reduced heterozygosity compared to native-range populations. Lumnitzera racemosa was introduced multiple times during the 1960s and 1970s, it has spread rapidly into a forest composed of native R. mangle, A. germinans, Laguncularia racemosa and Conocarpus erectus and now occupies 60,500 m2 of mangrove forest with stem densities of 24,735 ha-1. We estimate the population growth rate of Lumnitzera racemosa to be between 17 and 23% year-1. Populations of both species of naturalized mangroves are dominated by young individuals. Given the long life and water-dispersed nature of propagules of the two exotic species, it is likely that they have spread beyond our survey area. We argue that the species-depauperate nature of tropical Atlantic mangrove forests and close taxonomic relatives in the more species-rich Indo-Pacific region result in the susceptibility of tropical Atlantic mangrove forests to invasion by Indo-Pacific mangrove species.

Variação no conteúdo protéico e pigmentar em variantes cromáticas de Gracilaria domingensis nas populações naturais de Rio do Fogo-RN, BRASIL

The seaweed Gracilaria domingensis is a common species in the coast of Rio Grande do Norte. This species lives in the intertidal zone, where colour strains (red, green and brown) co-occur during the whole year. Seaweeds that live in this region are exposed to daily changes and to the rhythm of the tide. During the low tide they are exposed to dissection, hiper-or hipo-osmotic shock, high temperatures and high irradiance. The aim of this study was to analyze whether the pigment and protein content of the colour strains of G. domingensis is affected by some environmental parameters in a temporal scale. The seaweeds were collected during 10 months in the seashore of Rio do Fogo (RN). The total soluble proteins and the phycobiliprotein were extracted in phosphate buffer and the carotenoids were analyzed by a standardized method through HPLC-UV. The pigments analysis showed that phycoerithrin is the most abundant pigment in the three strains. This pigment was strongly correlated with nitrogen and the photosynthetically active radiation. Chlorophyll presented higher concentrations than carotenoids during the whole, but the ratio carotenoid/chlorophyll-a was modified by incident radiation. The most abundant carotenoid was ß-carotene and zeaxanthin, which had higher concentrations in the higher radiation months. The concentration increase of zeaxanthin in this period indicated a photoprotective response of the seaweed. The three strains presented a pigment profile that indicates different radiation tolerance profile. Our results pointed that the green strain is better adapted to high irradiance levels than the red and brown strains

Contribution à l'étude du peuplement du littoral rocheux du Vietnam (sud)

In this part 1, after a brief description of the habitat, the author describes in details (in descending order) the supralittoral, littoral and infralittoral zones. The author describes many permanent groups of Cyanophyceae in the higher horizon of intertidal zone, the cosmopolitan group of Navicula Grevillei, Hildenbrandtia prototypus, the pantropical group of Calothrix pilosa, Chaetomorpha antennina, indopacific group of Dermonema Frappieri, Sargassum, Padina, Thatassia Hemprichii, Halophila. The group of cold or temperate habitat with Bangiophycideae are present in winter. Some are described, formed by the oysters, Vermetus or Cirripeds, or by the algae (Calothrix, Brachytrichia, Gelidium, Dermonema, Chaetomorpha).

The Kinome of Pacific Oyster Crassostrea gigas, Its Expression during Development and in Response to Environmental Factors

Oysters play an important role in estuarine and coastal marine habitats, where the majority of humans live. In these ecosystems, environmental degradation is substantial, and oysters must cope with highly dynamic and stressful environmental constraints during their lives in the intertidal zone. The availability of the genome sequence of the Pacific oyster Crassostrea gigas represents a unique opportunity for a comprehensive assessment of the signal transduction pathways that the species has developed to deal with this unique habitat. We performed an in silico analysis to identify, annotate and classify protein kinases in C. gigas, according to their kinase domain taxonomy classification, and compared with kinome already described in other animal species. The C. gigas kinome consists of 371 protein kinases, making it closely related to the sea urchin kinome, which has 353 protein kinases. The absence of gene redundancy in some groups of the C. gigas kinome may simplify functional studies of protein kinases. Through data mining of transcriptomes in C. gigas, we identified part of the kinome which may be central during development and may play a role in response to various environmental factors. Overall, this work contributes to a better understanding of key sensing pathways that may be central for adaptation to a highly dynamic marine environment.

Spatial distribution patterns and movements of Holothuria arguinensis in the Ria Formosa (Portugal)

Holothurian populations are under pressure worldwide because of increasing demand for beche-de-mer, mainly for Asian consumption. Importations to this area from new temperate fishing grounds provide economic opportunities but also raise concerns regarding future over-exploitation. Studies on the habitat preferences and movements of sea cucumbers are important for the management of sea cucumber stocks and sizing of no-take zones, but information on the ecology and behavior of temperate sea cucumbers is scarce. This study describes the small-scale distribution and movement patterns of Holothuria arguinensis in the intertidal zone of the Ria Formosa national park (Portugal).Mark/recapture studieswere performed to record theirmovements over time on different habitats (sand and seagrass). H. arguinensis preferred seagrass habitats and did not show a size or life stage-related spatial segregation. Its density was 563 ind. ha−1 and mean movement speed was 10 m per day. Movement speed did not differ between habitats and the direction of movement was offshore during the day and shoreward during the night. Median home range size was 35 m2 and overlap among home ranges was 84%. H. arguinensis' high abundance, close association with seagrass and easy catchability in the intertidal zone, indicate the importance of including intertidal lagoons in future studies on temperate sea cucumber ecology since those systems might require different management strategies than fully submerged habitats.

Variação no conteúdo protéico e pigmentar em variantes cromáticas de Gracilaria domingensis nas populações naturais de Rio do Fogo-RN, BRASIL

The seaweed Gracilaria domingensis is a common species in the coast of Rio Grande do Norte. This species lives in the intertidal zone, where colour strains (red, green and brown) co-occur during the whole year. Seaweeds that live in this region are exposed to daily changes and to the rhythm of the tide. During the low tide they are exposed to dissection, hiper-or hipo-osmotic shock, high temperatures and high irradiance. The aim of this study was to analyze whether the pigment and protein content of the colour strains of G. domingensis is affected by some environmental parameters in a temporal scale. The seaweeds were collected during 10 months in the seashore of Rio do Fogo (RN). The total soluble proteins and the phycobiliprotein were extracted in phosphate buffer and the carotenoids were analyzed by a standardized method through HPLC-UV. The pigments analysis showed that phycoerithrin is the most abundant pigment in the three strains. This pigment was strongly correlated with nitrogen and the photosynthetically active radiation. Chlorophyll presented higher concentrations than carotenoids during the whole, but the ratio carotenoid/chlorophyll-a was modified by incident radiation. The most abundant carotenoid was ß-carotene and zeaxanthin, which had higher concentrations in the higher radiation months. The concentration increase of zeaxanthin in this period indicated a photoprotective response of the seaweed. The three strains presented a pigment profile that indicates different radiation tolerance profile. Our results pointed that the green strain is better adapted to high irradiance levels than the red and brown strains