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Temporal variability and the vertical shoreline profile of an intertidal macroalgal assemblage were examined on the coast of Barton Peninsula, Maxwell Bay, King George Island, Antarctica. Sampling was performed during the three austral summer seasons from November 2016 to January 2019. The sampling interval for the summer shift was 1–2 months. Eighteen algal species were identified, with 75% relative coverage of the predominant red alga Iridaea cordata and endemic brown alga Phaeurus antarcticus. Temporal variation in the macroalgal assemblage showed 78.35% similarity between one month and 64.61% similarity between two months. Contour plots for visualizing macroalgal distribution were first attempted in this study, and compared to general distribution of tables and diagrams that were discontinuously expressed. The coastscape was expressed more quantitatively and continuously, and was also useful for explaining temporal changes such as summer abundance can be described as a shift from I. cordata to P. antarcticus. In addition, in terms of species composition, this study area corresponds to the middle to lower intertidal zone and shows the highest species diversity in King George Island, so it is expected to provide important information for the researches in Antarctic intertidal zones.

Temporal variability and the vertical shoreline profile of an intertidal macroalgal assemblage were examined on the coast of Barton Peninsula, Maxwell Bay, King George Island, Antarctica. Sampling was performed during the three austral summer seasons from November 2016 to January 2019. The sampling interval for the summer shift was 1–2 months. Eighteen algal species were identified, with 75% relative coverage of the predominant red alga Iridaea cordata and endemic brown alga Phaeurus antarcticus. Temporal variation in the macroalgal assemblage showed 78.35% similarity between one month and 64.61% similarity between two months. Contour plots for visualizing macroalgal distribution were first attempted in this study, and compared to general distribution of tables and diagrams that were discontinuously expressed. The coastscape was expressed more quantitatively and continuously, and was also useful for explaining temporal changes such as summer abundance can be described as a shift from I. cordata to P. antarcticus. In addition, in terms of species composition, this study area corresponds to the middle to lower intertidal zone and shows the highest species diversity in King George Island, so it is expected to provide important information for the researches in Antarctic intertidal zones.

The molluscan fauna inhabiting the algal turfs of mesolittoral rocky outcrops, dominated by the coralline alga Ellisolandia elongata, has been quantitatively analysed in a Marine Protected Area of Málaga, southern Spain (W Mediterranean). A total of 2520 mollusc specimens belonging to 46 species were identified. This taxocenosis was compared to that previously studied from the infralittoral level, where the alga Halopteris scoparia was prevailing and 4084 specimens belonging to 66 species of Mollusca were found. The species Pisinna glabrata, Skeneopsis planorbis, Nodulus spiralis and Tricolia miniata dominated the mesolittoral stage. The occurrence of congeneric species pairs (Tricolia miniata/Tricolia pullus, Nodulus spiralis/Nodulus contortus) which achieve high abundance in one of the levels and are scarce or absent in the other was striking. Therefore, the coralline algal turf in the lower part of the intertidal zone is not just an extension of the “Photophilous Algae” community but a benthic community of its own.

Coastal areas are subjected to several anthropogenic stressors with much of the world's intertidal areas receding due to human activities, coastal erosion and sea level rise. The Dutch Eastern Scheldt (ES) has been predicted to lose around 35% of intertidal areas by 2060. This study investigates differences between biogeochemical fluxes of intertidal and subtidal sediments of the ES and assesses how ongoing erosion may modify the sedimentary ecosystem functioning of this coastal bay in the coming decades. Monthly fluxes and porewater concentrations of dissolved inorganic nitrogen (DIN), phosphorous (DIP), silica (DSi), carbon (DIC) and oxygen (O2) as well as organic matter (OM) characteristics were measured from intertidal and subtidal sediments from June 2016–December 2017. Compared to subtidal stations, OM was significantly more reactive in intertidal samples and exhibited 37% higher O2 fluxes, suggesting a strong influence from microphytobenthos. Subtidal sediments exhibited an average efflux of nitrates (0.28 mmol m−2 d−1) and phosphates (0.09 mmol m−2 d−1) into the water column, while intertidal areas displayed average influxes (nitrates = −1.2 mmol m−2 d−1, phosphates = −0.03 mmol m−2 d−1) directed into the sediment. The calculated removal of total DIN and DIP from the water column was 34–38% higher in intertidal compared to subtidal samples suggesting stronger denitrification and phosphorus adsorption to solid particles from intertidal sediments. As an upscaling exercise, we estimate potential erosion induced changes if the ES stations are representative for the system. With this assumption, we estimate 11% and 8% reductions for respective nitrogen and phosphorus removal in the entire ES by 2060. Given the global observations of eroding intertidal areas and rising sea levels, we suggest that the predicted habitat loss may cause significant changes for coastal biogeochemistry and should be investigated further to understand its potential consequences.

Predicting sediment transport at sandy beaches is a significant challenge in civil engineering owing to the variability in hydrodynamic, morphological, and geotechnical properties within a site and across multiple sites. Additionally, there are difficulties in measuring in-situ properties, and challenges in identifying and quantifying the different relevant driving and resisting forces. These challenges are further exacerbated in the intertidal zone where the addition of infiltration-exfiltration, wave run-up and run-down, bore collapse, cyclic emergence and submergence of sediments, interactions between standing waves and incident bores, and other processes must be considered. Among these many processes, pore pressure gradients within sandy beach sediments affect sediment transport by reducing the sediment's effective stress to zero (this process is called liquefaction). Despite the known importance of these pressure gradients with respect to sediment transport, there has been little field evidence of the role that these pore pressure gradients have on sediment transport, how they relate to the hydrodynamic properties, and their inclusion into predictive sediment transport equations. This study is based on field measurements of hydrodynamic and geotechnical properties, as well as pore pressure gradients during storm and non-storm conditions at sandy beaches in the intertidal zone. From the analysis of these field measurements, it was found that (1) liquefying pressure gradients are likely to develop in sediments that are rapidly inundated during storm conditions; (2) the magnitude of pore pressure gradients is related to the asymmetry of the pressure gradient and can occur with shoreward-directed near bed velocities; and (3) during non-storm conditions, pressure gradients that often do not exceed liquefaction criteria occurred more (less) frequently during a time period where erosion occurred in large (small) quantities, indicating that small non-liquefying pore pr

The Building with Nature approach has been gaining ground in hydraulic engineering, increasing the importance of understanding the cross-shore morphodynamic processes. The intertidal zone, where marine and aeolian processes come together, is an important link in the transport of sediment from the sea towards the dunes. The grain size distribution affects the sediment supply in the intertidal zone. This research investigates the effect of marine processes on the cross-shore variations of the grain size distribution in the intertidal zone by using a one-dimensional non linear shallow water XBeach model. The intertidal zone is subject to shoaling, surf and swash zone processes. The grain size influences the beach slope, the initiation of motion and settling to the bed. The cross-shore sediment transport is the combination of sediment that is stirred up from the bed and subsequently transported. Breaking induced turbulence enhances stirring of sediment from the bed and keeps sediment in suspension. The amount of stirring and the transport direction depends on the wave conditions. Input and control data for the model study was provided by the Scanex 2020 fieldwork campaign at Noordwijk, the Netherlands. The ADV velocity data combined with a pressure signal has been used for the tidal and incoming wave signal. Cross-shore profiles have been determined in Matlab based on terrestrial laser scans. Soil samples of the intertidal zone were taken with a sand scraper and analyzed with a sieve tower. For the initial grain size distribution is the average distribution of 14 samples on a transect was used. Based on wave, wind and soil sampling data a model period from 29-2-2020 02:00 to 10-3-2020 13:00 was selected. The XBeach model used is as described by Reniers et al. (2013), but with a time-averaged turbulent kinetic energy and a different implementation of the Riemann boundary. The model consisted of a 176 x 3 grid with a grid size of dx=1 m and dy=5 m. For the in, Civil Engineering | Hydraulic Engineering

Physical factors affecting the survival of Tachypleus tridentatus eggs were investigated by translocating their eggs between the high intertidal zone and the low intertidal zone of a known spawning site. The mean egg survival rates per day were highest in the mid intertidal zone (45.1 ± 25.4%) and lowest in the low intertidal zone (13.3 ± 27.6%). Differences in the elevation, air exposure time, and water content of the spawning ground were significant factors determining the egg survival rates. Excessive or insufficient air exposure time resulted in inadequate water content at higher and lower intertidal zones reducing egg survival. On the other hand, moderate saturation and dehydration were repeated with each tidal movement in the mid intertidal zone. This dynamic is considered one of the crucial factors for the survival of eggs and is considered optimal for spawning. Therefore, the protection of the mid intertidal zone is imperative for maximizing the egg survival rate in Tsuyazaki Cove where almost all suitable nesting sites have disappeared due to coastal development. By protecting these optimal sites for spawning and recovering other optimal sites on suitable beaches a positive contribution could be made to future management and conservation. The study also suggests the possibility of translocating eggs from marginal to optimal spawning sites as a recovery strategy for this globally endangered species.

In order to test if there is a connection between sediment structure and the abundance of certain Polychaeta, samples of three different spots in the intertidal zone of the wadden sea on Sylt were analysed with respect to species composition and population density of bristleworms. We examined two different kinds of sediment, muddy sands and mudflats. There was a clear dominance of Nereis virens and a lack of other species in the muddy sands, whereas the mudflats showed a high diversity of different Polychaeta such as Heteromastus filiformis, Tharyx killariensis or Scoloplos armiger. The muddy sands, however, receive influx of organic material from a pipe and are partially isolated from the rest of the wadden sea, which might have an impact on Polychaeta diversity. Analysis of sediment properties showed only few differences in grain size between the two spots. Finally, our findings consider anthropogenic pollution and the isolated position of the muddy sands near Lister Haken on Sylt to cause a clear decrease in local biodiversity in comparison to the adjacent mudflats., Um zu prüfen, ob ein Zusammenhang zwischen Sedimentstruktur und Abundanz bestimmter Polychaeta besteht, wurden Proben von drei verschiedenen Stellen in der Gezeitenzone des Wattenmeeres auf Sylt hinsichtlich Artenzusammensetzung und Populationsdichte von Borstenwürmern untersucht. Wir untersuchten zwei verschiedene Arten von Sedimenten, schlammigen Sand und Wattenmeer. In den Schlammsanden herrschte eine deutliche Dominanz von Nereis virens und ein Mangel an anderen Arten, während das Watt eine hohe Diversität verschiedener Polychaeta wie Heteromastus filiformis, Tharyx killariensis oder Scoloplos armiger aufwies. Die schlammigen Sande erhalten jedoch organisches Material aus einem Rohr und sind teilweise vom Rest des Wattenmeeres isoliert, was einen Einfluss auf die Polychaeta-Vielfalt haben könnte. Die Analyse der Sedimenteigenschaften zeigte nur wenige Unterschiede in der Korngröße zwischen den beiden Spots. Schließlich gehen unsere Ergebnisse davon aus, dass anthropogene Belastungen und die isolierte Lage der Schlammsande beim Lister Haken auf Sylt eine deutliche Abnahme der lokalen Biodiversität im Vergleich zum angrenzenden Watt verursachen., Peer Reviewed

Durch eine Beobachtung in der Gezeitenzone von Le Cabellou in der südlichen Bretagne ist uns aufgefallen, dass Actinia fragacea nur bis in das mittlere Eulitoral vorkommt. Die Amplitude der Verbreitung von Actinia equina ist größer, da das Vorkommen von Actinia equina bis in das obere Eulitoral reicht. Diese Hypothese haben wir im September 2016 untersucht, in dem wir Transekte in die Gezeitenzone von Le Cabellou gelegt haben. Die aufgenommenen Daten der Anthozoa zwischen dem Supralitoral und dem Sublitoral haben gezeigt, dass Actinia equina im oberen Eulitoral vorherrschend ist. Dadurch konnte unsere Hypothese bestätigt werden. Zudem lässt die Untersuchung Rückschlüsse auf die unterschiedliche Ökologie von Actinia equina und Actinia fragacea zu., Through an observation in the intertidal zone of Le Cabellou in southern Brittany, we noticed that Actinia fragacea only occurs as far as the middle eulittoral. The amplitude of the distribution of Actinia equina is greater, since the occurrence of Actinia equina extends into the upper eulitoral. We examined this hypothesis in September 2016 when we placed transects in the intertidal zone of Le Cabellou. The recorded data of the anthozoa between the supralitoral and the sublittoral have shown that Actinia equina is predominant in the upper eulitoral. This confirmed our hypothesis. In addition, the study allows conclusions to be drawn about the different ecology of Actinia equina and Actinia fragacea., Peer Reviewed

Like many traditional water systems, salt fields in the coastal region of Danzhou are now facing unprecedented challenges from social development and climate change. In an era of rapid urbanization and tourism development, the project aims to provide a landscape approach that balances historical preservation with the development of local public life and tourism. By exploring the potential of the landscape narrative, the project uses landscape elements such as heritage structure, local material, local plants, buildings and roads to make salt heritage, a valuable cultural heritage, a driving force for the development of traditional salt villages. When the historic, economic and ecological value of salt fields is revalued, these traditional water systems can be revived and provide more opportunities for a coastal area to develop into a resilient system., Architecture, Urbanism and Building Sciences | Landscape Architecture

In order to understand the long term behavior of intertidal ridge-runnel systems high resolution spatial and temporal data covering extended periods of time is needed. Such datasets are still rare but are becoming more available through the usage of remote sensing technologies such as Argus and Terrestrial Laser Scanning. A three month period (Feb – April 2020) with data obtained by laser scanning at the beach of Noordwijk, the Netherlands, has been analysed to evaluate the longshore variability of rip channels. During this period varying weather conditions occurred. The timeseries consist out of snapshots taken around the occurrence of the lowest tidal water level each day, containing elevation data of an 1km alongshore section of the beach. Each scan in this timeseries is processed in order to remove noise, objects and correct for time dependent rotations. The spatial gaps in the scans present in the data as the result of flowing or standing water are interpolated using a 2D grid interpolation method. The analysis is done using two different methods: a 1D-method using longshore elevation transacts, and a more advanced 4D-Object-by-Change based upon elevation changes over time. The 1D-method detected 44 rip channels that existed for multiple days, with an average alongshore migration rate of 1.55 m/day. The average spacing between rip channels was found to be 131 meters. The 4D-OBC detected less rip channel when compared to the 1D-method but did capture other morphological features such a runnels. A comparison of the alongshore migration rates and the dominant wave and wind directions that during this period showed a correlation between wind and wave direction and the direction of the alongshore migration direction, however some exceptions are visible. Comparing this research to similar research and literature did show differences in the migration rates and rip spacing. These are explained by the different nature of both datasets (2D vs 3D) and methodology used in

Purpose: The intertidal and supratidal coastal zone challenges the osmoregulatory capacity of aquatic inhabitants. Four new species of Gyrodactylus ectoparasites on two intertidal fishes from Chile are described based on molecular and morphological analyses. Methods: Monogeneans were found from two fish species, the clingfish Sicyases sanguineus Müller & Troschel, 1843 and the combtooth blenny Scartichthys viridis Valenciennes, 1836. The morphology was described by drawings, and minimal measurements. The parasites were barcoded via the sequencing of the ribosomal DNA over ITS1–5.8S–ITS2. Results: The air-breathing clingfish S. sanguineus carried Gyrodactylus amphibius sp. nov., hiding in the ventral sucker formed by the modified pectoral fins of the fish. The intertidal combtooth blenny S. viridis carried three other new species: Gyrodactylus scartichthi sp. nov., Gyrodactylus viridae sp. nov., and Gyrodactylus zietarae sp. nov. Conclusion: The four new species were all phylogenetically related with the previously described G. chileani Ziętara et al. 2012 on triplefin Helcogrammoides chilensis Cancino, 1960 in the same habitat. Thus, the five Chilean Pacific Gyrodactylus species formed a statistically well-supported (100%) monophyletic clade together with three geographically distant species recorded in Europe. The Chilean Pacific parasites are not related to G. salinae and G. magadiensis, parasites described in extreme osmotic stress environments earlier.

Mediterranean Sea has been proposed as the sixth greatest accumulation zone for marine litter and the most affected regarding to microplastics (MPs). Tarragona (Catalonia, NE Spain) coastal region suffers high pressure due to urbanization, tourism, industrial harbour and petrochemical/plastic industries. The present study aims to quantify and characterize in size, morphology and composition the MPs present in sandy beaches, marine sediments, and surface seawaters of Tarragona coastal region. MPs mean abundance were 1.30 items/m(3) in surface seawaters, 32.4 items/kg in marine sediments, and 10.7 items/kg in sandy beaches. Polyester fibres were dominant MPs in bottom sediments and seawater meanwhile polyethylene and polypropylene fragments were the main MPs in beaches. The fibres balls associated with bottom sediments, organic matter and plankton were abundant, masking the real quantity of fibres in each reservoir. The abundance by volume of seawater MPs was higher to those found in oceanic areas and similar to other areas of Mediterranean Sea, corroborating that Western Mediterranean Sea as a region of MPs accumulation. MPs composition and abundance suggested the input of numerous land-base-sources, WWTP (wastewater treatment plants) effluents discharges, and emissaries as the most important. Marine MPs pollution were studied from an integrative point of view, that indudes superficial sea water, sand from beaches and sediments. The dynamics of MPs in Tarragona coast were characterized by seawater as the media that receive and facilitate dispersion and fragmentation. The shoreline acts as an intermediate reservoir with constant weathering and active exchange with seawater surface and the sediments acts as a significant sink for medium MPs sizes. It is necessary to develo

Tides are a major component of the interaction between the marine and terrestrial environments, and thus play an important part in shaping the environmental context for the evolution of shallow marine and coastal organisms. Here, we use a dedicated tidal model and palaeogeographic reconstructions from the Late Silurian to early Late Devonian (420Ma, 400Ma and 380Ma, Ma=millions of years ago) to explore the potential significance of tides for the evolution of osteichthyans (bony fish) and tetrapods (land vertebrates). The earliest members of the osteichthyan crown-group date to the Late Silurian, approximately 425Ma, while the earliest evidence for tetrapods is provided by trackways from the Middle Devonian, dated to approximately 393Ma, and the oldest tetrapod body fossils are Late Devonian, approximately 373Ma. Large tidal ranges could have fostered both the evolution of air-breathing organs in osteichthyans to facilitate breathing in oxygen-depleted tidal pools, and the development of weight-bearing tetrapod limbs to aid navigation within the intertidal zones. We find that tidal ranges over 4m were present around areas of evolutionary significance for the origin of osteichthyans and the fish-tetrapod transition, highlighting the possible importance of tidal dynamics as a driver for these evolutionary processes.

Digestive microbiota provides a wide range of beneficial effects on host physiology and are therefore likely to play a key role in marine intertidal bivalve ability to acclimatize to the intertidal zone. This study investigated the effect of intertidal levels on the digestive bacterial microbiota of oysters Crassostrea gigas and clams Ruditapes philippinarum, two bivalves with different ecological niches. Based on the 16S rRNA region sequencing, digestive glands, seawater and sediments harbored specific bacterial communities, dominated by OTUs assigned to the Mycoplasmatales, Desulfobacterales and Rhodobacterales orders, respectively. Field implantation modified digestive bacterial microbiota of both bivalve species according to their intertidal position. Rhodospirillales and Legionellales abundances increased in oysters and clams from low intertidal level, respectively. After a 14-day depuration process, these effects were still observed especially for clams, while digestive bacterial microbiota of oysters were more subjected to short-term environmental changes. Nevertheless, 3.5 months stay on intertidal zone was enough to leave an environmental footprint on the digestive bacterial microbiota, suggesting the existence of autochthonous bivalve bacteria. When comparing clams from the three intertidal levels, 20% of the bacterial assemblage was shared among the levels and it was dominated by OTU affiliated to the Mycoplasmataceae and Spirochaetaceae families.

Wave height was used as a proxy to assess the effect of hydrodynamics on the development and structure of intertidal North-East Atlantic rocky macroalgal communities (Brittany). The characterization of hydrodynamics at small-scale (about 10 m) was performed through wave height in situ monitoring using pressure sensors. Both the diversity and the cover of the macroalgal communities were sampled in parallel. Wave heights exhibit large variations with values ranging from ca. 5 cm to 1.60 m. We show that wave height directly controls the cover of macroalgal canopies (Pearson's r between −0.62 and −0.39). In all communities, most of the fucoid covers regressed with increasing wave height values. By contrast, positive correlations were found at low shore levels between wave heights and the cover of the kelp Laminaria digitata and also of several species of Rhodophyta. Redundancy analysis points out the significant effect of wave height on the inner variability of macroalgal communities, explaining up to 19% of their upright structure and more than 15% of the distribution of canopy-forming groups. In assemblages dominated by either Pelvetia canaliculata or Fucus serratus, a significant negative correlation was also evidenced with the index of community structure (Ics), which gives an appraisal of both the structure and the development of macroalgal communities. In conclusion, this study provides a novel experimental approach helping to quantify the effects of hydrodynamics on the structure of macroalgal communities using a small-scale in situ quantification of wave heights, revealing hydrodynamics as the main environmental driver of inner structural variations in seaweed assemblages.

This exegesis situates my work in the intertidal zone. In Australia the intertidal zone is a site of historic, cultural, and ecological significance. It is my argument that thinking intertidally attunes us to concepts of inbetweenness and interconnection. These concepts are further articulated in relation to contemporary understandings of nature as outlined in different ways by Timothy Morton and Jane Bennett. Contemporary artists Mark Dion and Fiona Hall both draw on museological representations of nature to critique taxonomic classificatory logics — their work informs my rejection of such perspectives. Considering art and politics in the intertidal zone, where boundaries between inside and outside, nature and culture are porous and shifting informs my discussion of artistic influences of my practice including Anne Hamilton, Jonathon Jones and Fiona Foley and Janet Laurence. My process driven approach to art making, drawing on recent understandings of nature, artists exploring ecological concerns and material concerns of making has informed my immersive installations of kinetic sculpture and drawings. These aim to provide a rich sense of the interconnection between people and nature informed by the diverse materiality of the intertidal zone.

This study describes an unusual case of trampling on intertidal rocky shores by the largest rodent, the capybara, Hydrochoerus hydrochaeris (Linnaeus, 1766). Groups of capybaras were sighted swimming, diving and resting along the rocky shores of Anchieta Island State Park, Brazil. The possible effects of daily trampling on rocky shores by a large and uncontrolled capybara population are discussed, and management and research interventions are proposed., Este estudo descreve um caso incomum de pisoteio nos costões rochosos entremarés pela maior espécie de mamífero roedor, a capivara, Hydrochoerus hydrochaeris (Linnaeus, 1766). Grupos de capivaras foram observados nadando, mergulhando e descansando ao longo de costões rochosos do Parque Estadual da Ilha Anchieta, Ubatuba, São Paulo. São discutidos os possíveis efeitos do pisoteio diário em costões rochosos por uma grande e incontrolada população de capivaras, bem como as intervenções de manejo e pesquisa necessárias.

Two species of intertidal insects are reported from Galicia for the first time (NW Iberian Peninsula): Myrmecopora (Xenusa) sulcata (Kiesenwetter, 1850) and Brundinia marina (Mulsant & Rey, 1853) (Coleoptera, Staphylinidae, Aleocharinae). The previous Iberian records are commented and some data on the distribution and ecology of those species are also provided., Se citan por primera vez en Galicia (N.O. de la Península Ibérica) dos especies de insectos de la zona intermareal: Myrmecopora (Xenusa) sulcata (Kiesenwetter, 1850) y Brundinia marina (Mulsant & Rey, 1853) (Coleoptera, Staphylinidae, Aleocharinae). Se comentan los registros ibéricos previos y también se aportan algunos datos sobre la distribución y ecología de dichas especies.

New records of three species of insects occurring on the intertidal zone of some coastal areas of Galicia (NW Iberian Peninsula) are presented: Aepus gallaecus Jeannel, 1926, Aepopsis robinii robinii (Laboulbène, 1849) (Coleoptera, Carabidae), and Aepophilus bonnairei Signoret, 1879 (Hemiptera, Aepophilidae). The previous records in the Iberian Peninsula are compiled and commented, and some data on the distribution and ecology of those species are provided., Se presentan nuevos registros de tres especies de insectos presentes en la zona intermareal de algunas áreas costeras de Galicia (N.O. de la Península Ibérica): Aepus gallaecus Jeannel, 1926, Aepopsis robinii robinii (Laboulbène, 1849) (Coleoptera: Carabidae, Trechini) y Aepophilus bonnairei Signoret, 1879 (Hemiptera, Aepophilidae). Se recopilan y comentan los registros previos en la Península Ibérica y se aportan algunos datos sobre la distribución y ecología de dichas especies.

Kelp are ecologically important organisms because they provide food and habitat to many other creatures. On wave-swept rocky shores, kelp must withstand the force of moving water from waves and currents, while also growing to large sizes to outcompete neighboring macroalgae for light and space. If the forces from moving water (e.g. drag) exceed the strength of the kelp, the kelp can be damaged or dislodged from the shoreline, effectively removing the kelp from the ecosystem. Here, I use the intertidal kelp Egregia menziesii, one of the largest kelp found in the rocky intertidal zone along the west coast of North America, to investigate how the kelp’s growth and structure are affected by, and alter its interaction with, moving water in waves, as well as the animals that use the kelp for food and habitat.In Chapter One, I examine how the gas-filled bladders (pneumatocysts) of kelp help keep the fronds of E. menziesii afloat in wave-driven flow. Field surveys revealed that this species shows great variation in pneumatocyst size, number, and location on fronds. In laboratory towing-tank studies, I found that drag on pneumatocysts was reduced when they were bent over by flowing water. The drag due to pneumatocysts was small compared to the drag on a whole frond. At flow speeds up to 0.58 m s-1, the buoyant force exerted by a pneumatocyst was greater than the drag it experienced. In wave-tank experiments using models of fronds with pneumatocysts at different positions, the pneumatocysts were most effective at lifting fronds high in the water column when they were located at the distal tips of the fronds, both in small and large waves. However, if fronds had pneumatocysts that were not at the tip, an increase in the peak velocities of waves led to an increase in the heights of the fronds in the water column. In the field, pneumatocysts did not affect the back-and-forth horizontal motion of E. menziesii exposed to waves, but fronds with pneumatocysts were higher in the wate

Information dealing with different ecological aspects of gastropod mollusks in Mexico is insufficient, especially in marine priority regions (MPRs) that have been determined by the National Commission for Knowledge and Use of Biodiversity. In the state of Guerrero there are four MPRs. The aim of this research was to determine the richness, abundance, distribution, size composition and abundance and length relationship of the dominant species of the Fissurellidae family with the type of substrate and wave intensity (Mollusca: Gastropoda), which has been reported as representative family in the ro-cky intertidal zone in Guerrero. The work was carried out at 23 sites in the rocky intertidal zone. The specimens were collected at low tide and the sampling unit was 1 m2. The sampled area by site and collection was 10 m2. The specimens found within the sampling unit, were collected and preserved in 96 % alcohol. 1 669 specimens were analyzed; 14 species were identified. Fissurella morrisoni is reported as a new adhesion to the list of species of this family in Guerrero. Fissurella nigrocincta has the highest abundance with 1 043 agencies. It was determined that Fissurella. nigrocincta and Fissurella gemmata as species with wide distribution to be present in 90 % of sites. Fissurella gemmata has the greatest length in shell. The species with the greatest abundance and lengths have preferences for a substrate composed of rock masses and large blocks, where wave intensity is high., La información sobre los diversos aspectos ecológicos de interés de los moluscos gasterópodos en México es insuficiente, sobre todo en las regiones marinas prioritarias (RMPs), que la Comisión Nacional para el Conocimiento y Uso de la Biodiversidad ha decretado. En el estado de Guerrero existen cuatro RMPs. El objetivo de esta investigación fue determinar la riqueza, abundancia, distribución, composición de tallas y la relación de la abundancia y longitud de las especies dominantes de la familia Fissurellidae (Mollusca:Gastropoda), con el tipo de sustrato y la intensidad del oleaje, que ha sido reportada como familia representativa del intermareal rocoso de Guerrero. Se trabajó en la zona intermareal rocosa de 23 sitios; las colectas se realizaron durante la marea baja; la unidad de muestreo fue de 1 m2; el área muestreada por sitio y por colecta fue de 10 m2. Los especí-menes encontrados dentro de la unidad de muestreo se colectaron y preservaron en alcohol al 96 %. Se analizaron 1 669 especímenes, de los cuales, se identificaron 14 especies. Se reporta a Fissurella morrisoni como una nueva adhesión al listado de especies de esta familia en Guerrero. Fissurella nigrocincta registró la mayor abundancia con 1 043 organismos. Se determinó a Fissurella nigrocincta y Fissurella gemmata como de amplia distribución, al estar presentes en más del 90 % de los sitios. Fissurella gemmata registró la mayor longitud en concha. Las especies de mayor abundancia y longitud presentaron preferencias por un sustrato compuesto por macizos rocosos y grandes bloques, en donde la intensidad del oleaje es alta.

Rocky intertidal organisms are commonly exposed to environmental gradients, promoting adaptations to these conditions. Emersion time varies along the intertidal range and in the supralittoral zone is frequently larger than a single tidal cycle, even lasting for weeks. The planktonic-dispersing gastropod Melarhaphe neritoides is a common species of the high shore, adapted to reduce water loss in order to survive during long-term emersion. In this study, we investigated the molecular response, at the proteome level, of M. neritoides collected in high-shore tide pools to a series of emersion periods, from 8 to 24 days, in laboratory conditions. We compared this response to individuals maintained submerged during this period, because this was their original habitat. We also included a reversion treatment in the study, in which emersed individuals were returned to the submerged conditions. Although we detected an increase in overall protein concentration with longer emersion periods, contrary to general expectation, the two dimensional electrophoresis (2DE)-based proteomic analysis did not show significant differences between the treatments at the level of individual protein spots, even after an emersion period of 24 days. Our results suggest that the metabolism remains unaltered independent of the treatment carried out or the changes are very subtle and therefore difficult to detect with our experimental design. We conclude that M. neritoides could be equally adapted to emersion and submersion without drastic physiological changes

Characteristics of vertical distribution, species composition and biogeographical structure of macrobenthos of the intertidal communities of Kunashir Island (South Kurile Islands) are described. In the rocky and bouldery intertidal zones, communities dominated by barnacle Chthamalus dalli and a gastropod species Littorina sitkana with the poor species composition of the macrobenthos are typical for the upper intertidal subzone. The middle intertidal subzone is occupied by fucoid assemblages. The dense beds of laminarian algae dominate in the lower intertidal subzone with the total macrobenthic biomass up to 100 kg wet wt m?2. On wave-exposed sandy beaches formed by clean sand, populations of the macrobenthic organisms are very poor, and macrophytes and the other attached forms are absent. The communities dominated by eelgrass Zostera japonica and a gastropod species Batillaria cumingii are found only in the sandy intertidal zones of the southern coast of Kunashir Island, in Izmeny Bay. Reduction of species richness and increase of biomass of macrobenthos have been recorded from 1963 to 1991 in Izmeny Bay, and it is due to the fact that this area has been exposed to anthropogenic impact. At least, 563 species of macrobenthos are found in the intertidal zone of Kunashir Island. Pacific low-boreal and Pacific wide-boreal species are dominant. Warm-water species are more abundant in the intertidal zones of Izmeny Bay and on the Sea of Okhotsk coast as compared to those on the Pacific coast of Kunashir Island. It is probably associated with the flow patterns of the Soya Warm Current. Species composition and distribution of the intertidal macrobenthos of Kunashir Island are typical for the low-boreal intertidal zone with irregular diurnal and semi-diurnal tides. The intertidal zones of Kunashir Island and neighboring Shikotan Island have similar species composition and distribution patterns of the macrobenthic communities.

The Baie de Somme is an infilling estuarine environment, controlled by intensive marine hydrodynamics forcing (megatidal tide and waves) and a small river flow. Morpho-sedimentary dynamics of this bay and sedimentary fluxes were studied at two spatial and temporal scales. I) At the scale of intertidal hydraulic dunes, studied during semi-diurnal and semi-lunar tidal cycles with neap tides (NT) and spring tides (ST). In this context, a strong forcing variability (winds, tide, waves) control sedimentary fluxes and morphodynamics evolutions of dunes (λ : 5-23 m ; H : 20-60 cm). These fluxes generally increase with tide and waves, inducing a net sediment transport to the east or west, according to the predominance of current (flood/ebb), which depends on the characteristics of wind and waves. Low tide morphology of dunes depends on hydrodynamic conditions and sediment transport : asymmetry eastwards under a threshold water depth of 2,64 to 2,73 m. ; asymmetry westwards above this threshold, during quiet or agitated tide (Hs max < 1,5 m) ; sub-symmetry and flattening dunes during very agitated ST ( Hs max ≥ 1,83 m) ; asymmetry eastwards during a storming ST. Migration of dunes crests is more intense during ST than during NT and is not always in accordance with net sediment transport directions. It is due to significant variations in dunes morphology and polarity. During a semi-lunar tide cycle with waves, net sediment transport and dunes migrations are in direction of internal area of the bay (eastward). II) At the scale of the bay, studied to seasonal, annual and multiannual time steps, infilling dynamics is significant. Superficial sedimentary cover of the bay, observed in 2013, show a filtering gradient of sediment « offshore-coast » and « central axis-shoreline », with internal borders characterized by an increase in muds and carbonates rates between 1980 and 2013. At recent historical scale (1947-2011), orthophotos show a strong progress of coastal barriers (sand du, La Baie de Somme est un environnement estuarien en comblement, contrôlé par des forçages hydrodynamiques marins intenses (marée de type mégatidal et houle) et un faible régime fluviatile. La dynamique morpho-sédimentaire de cette baie, ainsi que les flux sédimentaires responsables, ont été étudiés à deux échelles spatiales et temporelles. I) A l'échelle de champs de dunes hydrauliques intertidales, étudiés durant des cycles de marées semi-diurnes et semi-lunaires de mortes-eaux (ME) et de vives-eaux (VE). Dans ce contexte, il s'avère que la forte variabilité des forçages (vents, marée, houle) contrôle les flux sédimentaires et les évolutions morphodynamiques des dunes (λ : 5-23 m ; H : 20-60 cm). Ces flux augmentent globalement avec le coefficient de marée et les conditions d'agitation, induisant un transport sédimentaire net vers l'est ou vers l'ouest, selon la prédominance des courants (flot/jusant), qui dépend des caractéristiques de vent et de houle. Les dunes adoptent une morphologie à basse-mer qui est dépendante des conditions hydrodynamiques du milieu et du transport sédimentaire : asymétrie vers l'est sous un seuil de profondeur d'eau de 2,64-2,73 m ; asymétrie vers l'ouest au-dessus de ce seuil, lors des marées calmes à agitées (Hs max < 1,5 m) ; sub-symétrie et aplatissement des dunes lors de VE très agitées (Hs max ≥ 1,83 m) ; asymétrie vers l'est lors d'une VE de tempête. La migration des crêtes de dunes est plus intense en VE qu'en ME et ne présente pas toujours de similitude avec les directions de transport sédimentaire net, ceci étant dû aux variations importantes de morphologie et de polarité. Durant un cycle de marée semi-lunaire assez agité, le transport sédimentaire net ainsi que la migration nette des dunes s'effectuent vers les zones internes de la baie (vers l'est). II) A l'échelle de la baie, étudiée aux pas de temps saisonniers, annuels et pluriannuels, la dynamique de comblement est importante. La couverture sédimentaire superficielle de la

Changes in spatiotemporal variability of aeolian sediment transport as result of bar welding are studied in this paper, within the scope of SEDEX²., Civil Engineering and Geosciences, Hydraulic Engineering / Coastal Engineering, Hydraulic Engineering and Water Resource Management (HEWRM), C73B23

The effect of grazers on the diversity, distribution, and composition of their principal food source has rarely been described for the high intertidal zone of rocky shores, a model system for studying the potential effects of climate change. Along rocky, wave-swept shores in central California, the microphytobenthos (MPB) supports diverse assemblages of limpets and littorine snails, which, at current benign temperatures, could potentially partition food resources in a complementary fashion, thereby enhancing secondary productivity. Two limpet species in particular, Lottia scabra and L. austrodigitalis, may partition components of the MPB, and are likely to affect the composition of the MPB on which they graze. In this study, we describe the composition, nutritional value (C:N ratio), and fluorescence (an index of chlorophyll density) of ungrazed, L. scabragrazed and L. austrodigitalis-grazed MPB, each as a function of temperature. Fluorescence de-creased with increased average daily maximum temperature for ungrazed MPB, but temperature had no discernible effects on either fluorescence or the composition of the MPB of grazed assemblages. L. austrodigitalis and L. scabra did not partition the MPB, and did not exhibit complementarity. Both species exhibited an ordered grazing scheme, in which limpets grazed down certain components of the MPB before others, and grazing increased the C:N ratio of the MPB, decreasing its nutritional value. Taken together, these results suggest that L. austrodigitalis and L. scabra may experience increased competition as warming temperatures reduce the available MPB.

西南日本において海産ユスリカの生態に関わる研究を行った。その結果，計20種が採集され，垂直分布では，潮間帯上部あるいは中部域のみに分布する種は少なかったが，下部域のみに分布する種は多かった。基質については岩石面や泥中のみに棲む種は少なかったのに対し，海藻類のみに棲む種は多かった。また，地理的分布では南西諸島や本土外洋沿岸域のみに分布する種は少なかった。一方，数種は，瀬戸内海沿岸と本土外洋沿岸域，本土外洋沿岸域と南西諸島，あるいは全地域に分布することが分かった。また，羽化時期については，Dicrotendipes enteromorphaeは夏季・秋季のみ，S. endocladiaeは周年出現し，他種は秋季・冬季のみあるいは冬季・春季のみに出現した。これらのことから，潮間帯には様々な生活様式を持つ多くの種のユスリカが棲息し，生態系において重要な役割を果たしていることが示唆された。, Ecological studies were conducted on marine chironomids in south-western Japan. A total of 20 species was collected. For vertical distribution, only a few species was distributed only at high or middle intertidal zone while many species were distributed only at low zone. For substrate preference, some species were collected only on rocks or in mud while many species were collected only in seaweeds. For geographical distribution, a few species was collected only in the southwestern islands or in the oceanic coast in the Japanese main islands. In contrast, some species were collected in the Seto Inland Sea and the oceanic coast in the main islands, in the oceanic coast in the main islands and the southwestern islands, or in all areas. For seasonal emergence, Dicrotendipes enteromorphae was collected only in summer and autumn, and Semiocladius endocladiae was collected in all seasons. Other species were collected only in autumn and winter, or only in winter and spring. These results suggest that many chironomid species with a variety of lifestyles dwell in intertidal zones and have some important roles in the ecosystems.

The intertidal zone is an ideal habitat to investigate effects of global warming because species living in it are very close to their physiological limits. Initial studies of invertebrate physiological responses to heat stress have employed relatively abrupt increases in temperature. My research investigates effects of ecologically more realistic temperature profiles on feeding in the intertidal hermit crab, Pagurus sameulis. Recent work in the Wright lab showed that feeding in this species is inhibited by an abrupt increase in temperature. Because temperature change in the natural environment of Pagurus is much more gradual, I hypothesize that such a gradual temperature profile might be more readily tolerated. I heated hermit crabs with a fast (10 min), medium (30 min) and slow (100 min) rate of change to 29°C. As hypothesized, consumption of food pellets upon reaching 29°C was undetectable after 10-minute heating. Pellet consumption after medium or slow heating to 29°C was significantly greater than after the rapid 10-min heating profile. Thus, these results proved my hypothesis correct: consumption of a squid pellet suggests that behavioral and physiological responses to high temperature are sensitive to the rate at which the high temperature is reached.

Aim Broad-scale patterns of heat stress play an important role in shaping the geographical distributions of many species and may differ from large-scale changes in average temperatures. For species living on rocky intertidal shores extreme heat stress occurs when hot dry aerial conditions coincide with midday low tides. We used empirical and modelled temperature data, and estimates of cumulative aerial exposure and solar radiation, in order to test the hypothesis that heat stress on Australian rocky intertidal shores decreases with increasing latitude. Location Rocky intertidal shores of south-eastern Australia spanning > 1500 km and 13° of latitude (26°24′23″ S to 39°07′47″ S). Methods In situ temperature measurements, hourly tidal elevations and daily solar radiation taken over three consecutive summers (December 2009-February 2012) were used to quantify latitudinal variability in extreme heat stress, cumulative aerial exposure and solar radiation, respectively. Comparisons between hourly in situ temperatures and meteorological data were used to produce a large-scale statistical model capable of estimating intertidal substratum temperatures during daytime low-tides, which was then extrapolated across 22 locations. Results Heat stress estimated using in situ loggers deployed across five east coast locations typically did not decline with increasing latitude and neither did midday exposure or solar radiation. The meteorological model proved to be a successful method for estimating rocky shore heat stress and in contrast to the empirical data displayed strong latitudinal trends in mean daily maxima and cumulative heat stress. Modelled acute heat stress (i.e. summer maxima), however, did not decline with increasing latitude, as there was greater thermal variability at higher latitudes. Main conclusions The meteorological model developed in this study represents a useful approach for estimating broad-scale patterns of heat stress on rocky intertidal shores. Results als

Seagrass meadows provide a wide variety of ecosystem services, but their distribution and health are adversely affected by man. In the present study, we examined the influence of coastal exploitation in terms of invertebrate harvesting and harbour activity on invertebrate community composition in subtropical seagrass meadows at Inhaca Island, Mozambique, in the Western Indian Ocean. There was a fivefold higher invertebrate density and biomass, and clearly higher invertebrate species richness, in the protected (control) site compared to the two exploited sites. The causes for the clear differences between protected and exploited sites were probably a result of (1) the directional outtake of large edible or saleable invertebrates (mostly molluscs) and the absence of boat traffic in the harvested site, and (2) harbour activities. Invertebrate community composition in the two exploited sites also differed (although less clear), which was likely due to inherent distinction in type of disturbance. Our findings revealed that protection of seagrass habitat is necessary and that disturbances of different origin might require different forms of management and conservation. Designing protected areas is however a complex process due to competition for use and space with activities such as invertebrate harvesting and harbours., AuthorCount:2

Proceedings of 4th JSPS-VAST Joint Seminar on 'Coastal Marine Science', Hai Phong, Viet Nam, 26-28 October 2009, Ocean Pollution

The gastropod communities around motu Tiahura are currently under various stresses, both natural and anthropogenic. Distribution studies can help understand how these pressures are affecting gastropod communities. The shallow waters around motu Tiahura were partitioned into six distinct habitats. Transects were examined in each habitat to observe gastropod abundance and diversity. Results show that the waters off the conglomerate platform are the most diverse, while the lagoon is least diverse. Three of the habitats were relatively similar in gastropod community, while the other three were distinct. Night transects revealed that burrowing gastropods form a distinct nocturnal community. Differences between gastropod communities may arise from biotic interactions and unique physical factors in each habitat.

Numerosos estudios en ecología marina se han enfocado en evaluar qué determina la estructura espacial y variabilidad temporal de los organismos que habitan la zona costera e intermareal. Nuestros resultados sugieren que individuos de Scartichthys viridis, separados espacialmente por una escala mayor a los 200 km, deberían ser demográficamente independientes, manteniendo actividades reproductivas y dinámicas poblacionales propias. Esta segregación espacial es sugerida a partir del análisis de elementos traza en los otolitos de reclutas, obtenidos simultáneamente de las localidades de Los Molles e Isla Negra, Chile central. Considerando el potencial de dispersión (92-106 días), basado en el conteo de micro incrementos diarios en otolitos, ambas poblaciones podrían estar conectadas. Sin embargo, la distribución vertical selectiva de sus estadios larvales favorecería su retención cerca de las áreas donde eclosionaron. Aunque el presente estudio no determina en particular los mecanismos biofísicos involucrados en la distribución larval, propone alternativas que pueden responder a tal interrogante. Estos resultados sientan un precedente para futuros estudios que permitan determinar explícitamente segregación poblacional a escalas espaciales menores, así como él o los mecanismos biofísicos que determinan el transporte, dispersión larval y conectividad poblacional de peces costeros intermareales., Several studies in marine ecology have focused on evaluating what determines the spatial and temporal structure of organisms within the intertidal and coastal zone. Our results suggest that individuals of Scartichthys viridis, separated by spatial scales greater that 200 km, would also be demographically separated, having independent reproductive activity and population dynamics. Such spatial difference is suggested by analyzing trace elements found in the otoliths of recruited specimens, which were obtained simultaneously from Los Molles and Isla Negra, central Chile. Considering larval dispersion potential (92-106 days), based on daily micro increments of otoliths, both populations could be connected. However, this may not be the case, since the behavioral trend of these fish during larval stages seems to be near the areas where they hatched. Although this study does not fully reveal the specific biophysical mechanisms involved, it proposes some alternatives that may address such questions. These results may assist in guiding further studies towards explicitly determining population segregation at minor spatial scales, as well as the specific biophysical mechanisms that determine transport, larval dispersion and population connectivity of fishes in intertidal environments.

For effects of tidal rhythms, intertidal bivalves are exposed to prolonged daily emersion periods during low tide. As a response to air exposure, the mussel Perumytilus purpuratus (Lamarck, 1819) closes its valves and shifts its metabolism to anaerobic pathways by the interruption of the oxygen flux. Consequently, body fluids low their pH causing the CaCO3 disolution of the shell, which would act as a pH buffer. In this study, the role of shell CaCO3 in the regulation of internal homeostasis at different periods of aerial exposure was evaluated. We measured the variation of pH, Ca2+ and HCO3 - concentrations in the extrapallial cavity and Ca2+ concentration at the shell of P. purpuratus individuals from the low and high intertidal zones. The results show that pH increases in the extrapallial cavity fluids during the emersion period in the laboratory, followed by a decrease of the shell Ca2+. Ca2+ and HCO3 - concentrations did not show a significant variation in extrapallial fluids during the aerial exposure periods. Moreover, significant differences were found in the Ca2+ and HCO3 - concentrations at the extrapallial fluids between individuals from low and high tidal levels. However, in the majority of measured variables, in spite of acclimation period, the basal levels were different between individuals from the low and high intertidal zones, suggesting physiological differences due to genetic differences among organisms inhabiting both zones, Por efecto de los ritmos de marea, los bivalvos intermareales quedan expuestos a prolongados periodos de emersión diarios durante las mareas bajas. Bajo estas condiciones, el mitílido Perumytilus purpuratus (Lamarck, 1819) cierra sus valvas y entra en anaerobiosis por la interrupción del flujo de oxígeno. En esta situación baja el pH de los fluidos corporales provocando la disolución del CaCO3 de las valvas y que actuaría como amortiguador de pH. En este estudio se evaluaron las fluctuaciones de pH, Ca2+ y HCO3 - en los fluidos de la cavidad extrapaleal y de Ca2+ en las valvas de individuos de P. purpuratus provenientes del intermareal bajo y alto, expuestos a periodos progresivos de emersión. Los resultados indican que el pH en los fluidos de la cavidad extrapaleal aumentó durante el periodo de emersión en laboratorio, lo cual fue seguido por una disminución de la concentración de Ca2+ de las valvas. Las concentraciones de Ca2+ y HCO3 - en los fluidos extrapaleales no mostraron variación significativa durante el tiempo de exposición aérea. Además, se encontraron diferencias significativas en las concentraciones de Ca2+ y HCO3 - de los fluidos extrapaleales entre individuos del intermareal rocoso alto y bajo. No obstante lo anterior y a pesar del periodo de aclimatación, los niveles de la mayor parte de las variables medidas presentaron un valor basal diferente entre individuos del intermareal bajo y alto, lo cual sugiere diferencias fisiológicas, debido a diferencias genéticas, entre individuos de ambas zonas.

The species composition and relative abundance of the annelid benthic macrofauna (Polychaeta and Oligochaeta) inhabiting the rocky intertidal zone of the ria of Ferrol (Galicia, NW Spain) were studied during field collections, from 2000 to 2002. A total of 14,619 specimens (11,585 polychaetes belonging to 76 species and 24 families and 3,034 oligochaetes belonging to 18 species and two families) were collected from 98 quantitative samples taken from 13 sampling sites. The general spatial distribution of the annelid fauna reflects an increase of the diversity from the inner to the outer part of the ria. The general patterns found in the annelid composition suggest that the assemblages were dominated by oligochaetes in the inner sheltered sampling sites and polychaetes in the outer more exposed sites. Several faunistical and taxonomical remarks on selected species are presented. Two new species of oligochaetes are described: Coralliodrilus artabrensis sp. n. and Pirodrilus fungithecatus sp. n. (Naididae, Phallodrilinae). A new biological index, based on the oligochaete/polychaete ratio (O/P), is proposed as tool to evaluate environmental quality and to monitor future changes in the environment.

A study was conducted in Arcachon Bay, France, to determine the effect of seasonal dynamics in a Zostera noltii meadow on P and Fe cycles in the superficial sediments of a tidal mudflat. The redox-sensitive Fe particulate pool and associated P in the root zone showed a seasonal variation following the growth and decay of Z. noltii biomass, with a maximum content during the growth period. In comparison, the bare sediments did not show significant seasonal changes. A dissolved inorganic phosphorus (DIP) uptake was measured from the water column to the sediment in vegetated sediments, whereas a net DIP efflux was observed in the unvegetated sediments. During the growth period, the formation of an iron oxihydroxide-rich zone occurred and acted as a trap for dissolved phosphorus, constituting a reserve of available P for eelgrass growth. At the periphery of the rhizosphere, a strong reduction of the sediment occurred during the growth phase, probably due to increasing organic matter inputs via the roots. The iron oxihydroxide dissolution releases Fe(II) and the recently bound phosphorus to the pore water, making it available for assimilation by the eelgrass roots for growth metabolism. Fe(II) is re-oxidized to solid Fe(III) forms depleted in P into the root zone, or re-precipitated below as sulphur forms. The highest P uptake occurs by this process, and the seasonal variations in redox-sensitive P stock are sufficient to support the annual Z. noltii P requirement. During the decline period, as the P plant demand and the oxic layer thickness drop, the unused released DIP pool supplies large amounts of DIP to the pore water and water column.

The rocky intertidal zones of southern California are important ecosystems, not only for biodiversity and coastal protection, but also for human interest and education. Like most ocean environments, these areas are sensitive to alteration due to human interference. Measuring the biodiversity in these areas is important, so scientists can track how species abundances and diversity change over time. The goal of this capstone project was to promote the awareness of human impact in the intertidal zone by creating a website. The website serves as a field guide, complete with photos for identification purposes, as well as information on how to lessen impact when visiting these tidepooling sites.

This study describes and quantifies the eumetazoan parasite community of the toadfish Aphos porosus (Valenciennes, 1837). To accomplish this purpose, 30 toadfish individuals were collected from intertidal rocky pools at El Tabo, Central Chile between October 2006 and January 2007. The descriptors of the parasite infracommunity (abundance, richness, diversity and eveness) were calculated and correlated with the host body weight to determine if these variables have any relationship. The trophic level in which the toadfish is positioned in its community is also suggested, according to the life cycles of the parasites found in the fish. From the total sample, 93% fish were parasitized and 2,104 parasite individuals, belonging to nine taxa, were collected. The cestodes of Tetraphyllidea and the nematode Pseudoterranova sp. were the most prevalent and abundant parasites. At the infracommunity level, only the abundances (numeric and volumetric) of parasites increased significantly with host body weight which may be a consequence of a major consumption of infected prey and accumulation of parasites because several parasite species were larvae and encysted in the celomatic cavity and muscles of the fish. At the infrapopulation level only Tetraphyllidea showed a significant correlation between abundances and host body size. The toadfish would be in an intermediate trophic level; it preys over crustaceans which are intermediate hosts for several parasite species found in this study. At the same time, toadfish can be preyed by elasmobranchs and marine mammals which usually are definitive hosts of most endoparasite species found., En este estudio se describe y cuantifica la comunidad de parásitos eumetazoos del bagre de mar Aphos porosus (Valenciennes, 1837). Con este objeto se recolectaron 30 ejemplares desde las pozas intermareales de El Tabo, Chile central, entre octubre 2006 y enero 2007. Se cuantificaron los descriptores infracomunitarios de parásitos (riqueza, abundancia numérica, abundancia volumétrica, dominancia, diversidad y uniformidad) y se correlacionaron con el peso corporal del hospedador para determinar si había relación entre estas variables. Se indagó sobre el nivel trófico que ocupa el bagre de mar en su comunidad de acuerdo a los ciclos de vida de los parásitos encontrados en este hospedador. El 93% de los bagres de mar estaba parasitado. Se recolectaron 2.104 individuos parásitos, pertenecientes a nueve taxones. Los cestodos de Tetraphyllidea y el nemátodo Pseudoterranova sp. fueron los parásitos más prevalentes y abundantes. A nivel infracomunitario sólo las abundancias (numérica y volumétrica) de parásitos aumentaron significativamente con el tamaño corporal del bagre de mar, lo que podría ser causa de una mayor ingesta de presas infectadas y a una acumulación de parásitos a medida que el hospedador crece, dado que varias especies parásitas se encontraron en estados larvales enquistados en la cavidad celomática y musculatura del pez, mientras que a nivel poblacional, sólo Tetraphyllidea aumentó en abundancia con el tamaño corporal del hospedador. El bagre de mar se ubicaría en un nivel trófico intermedio; depredaría sobre crustáceos, los cuales son hospedadores intermediarios de varias de sus especies parásitas, y a su vez, sería consumido por elasmobranquios y mamíferos marinos, principales hospedadores definitivos de la mayoría de los endoparásitos registrados.

Cupped oysters, Crassostrea gigas, often suffer abnormal mortalities during summer, at one year of age. Both scientists and professionnals are interested in finding practical methods to reduce these mortalities. The present study tries to answer two questions : 1- are there any differences of summer mortalities among various batches of spat available from spat collection areas (Arcachon and Charentes) ? 2- is it possible to improve summer survivals by wintering the spat at high air exposure locations (« hardening » procedure) ? The first comparison did not reveal any significant difference between the 16 batches of spat tested (mortalities between 5 % and 30 %). The second comparison in the same summer conditions was not able to show to any improvement from the « hardened » spat (all mortalities below 10 %). We can simply conclude from these two studies that no effect can be demonstrated in the years like 1998 unpropicious to mortalities., Les huîtres creuses, Crassostrea gigas, d'un an subissent depuis quelques années des mortalités en cours d'été, auxquelles scientifiques et professionnels recherchent des parades. L'étude proposée en 1998 cherche à répondre à deux questions : 1- y a-t-il une variabilité des performances d'élevage (de survie estivale en particulier) à partir des différents lots de naissain issus des bassins de captage (Arcachon et Charente) ? 2- est-il possible d'améliorer la survie estivale d'un lot de naissain, en lui faisant subir préalablement un traitement destiné à «l'endurcir» (hivernage en haut d'estran dans l'essai présent) ? La première comparaison portant sur 16 lots de naissain n'a pas mis en évidence de différence de survie estivale significative (mortalités comprises entre 5% et 30 %). La seconde montre que dans les mêmes conditions estivales, le naissain «endurci» durant l'hiver en haut d'estran ne manifeste pas des performances améliorées l'été suivant (mortalités toutes inférieures à 10 %). On peut seulement conclure qu'une année de faibles mortalités comme l'année 1998 n'est pas propice à la mise en évidence de facteurs éventuels d'amélioration de la survie estivale.

In 1990, a study of the phytobenthos of the rocky intertidal platforms in the Safi-Essaouira region (Sidi Boulbra, Western Morocco) was carried out at three sites. The intertidal zonation was analysed along permanent transects, and a qualitative and quantitative study of two characteristic units of the eulittoral vegetation - the vegetation belt of Fucus spiralis and the communities of Florideophyceae - was made. One hundred and twenty-nine macroalgal taxa and three phases were listed: 19 Ulvophyceae, 19 Fucophyceae, 1 Bangiophyceae and 93 Florideophyceae. The intertidal communities of the area are typical of semi-exposed and unpolluted platforms of Western Morocco, in the eulittoral zone, most of the typical Fucales that occur along the NE Atlantic coasts are absent, with the result that Florideophyceae are dominant. The composition and distribution of the communities are influenced by the short morphology (extensive platform, gentle slope and roughness degree), the substrate (sandstone), the occurrence of sediment and by high exposure to wave action. The vegetation belt of Fucus spiralis of Sidi Boulbra ranks floristically amongst the richest described in the NE Atlantic, and is characterized by the presence of southern species. The communities of Florideophyceae exhibit a mixture of exposed-shore, sheltered-shore and sand-tolerant species, resembling those described from SW Portugal. The dominant species change according to the season and environmental conditions. Over low-roughness platforms, an Osmundea, Gigartina (site 1) and a Leptosiphonia (site 3) community may be observed in winter-spring, and a Caulacanthus, Ceramium, Gelidium community in summer-autumn, Over extensive high-roughness platforms (site 2), this scheme is somewhat obscured by the development of varied Fucophyceae (Dictyotales, Sphacelariales). Moreover, any extensive destruction of eulittoral communities usually induces a green algal bloom (Ulvales). Amongst the common algae from Sidi Boulbra

Studies of the functioning of intertidal ecosystems are widely based on analyses of the biological rhythms due to sea movements, estimating an average rate for emersion at all points of the foreshore. This estimate supplies an explicative parameter related to distribution of animal and vegetable species. We present a spatial model for estimation of emersion rates based on the processing of geocoded data within a geographical information system (GIS).

This literature survey contains published information on wetlands vegetation of Alaska prior to September, 1977. The literature review and summaries are organized under the broad habitat categories of: (a) freshwater wetlands (ponds and lakes, freshwater marshes, peatlands, streams, and riparian gravel bars and cutbanks), and (b) saline or brackish water wetlands (strands and supratidal meadows, saline or brackish marshes, and intertidal zones). The floristics and vegetation of these categories are discussed on a regional basis which includes Southeastern Alaska, Southeastern Alaska, Southcentral Alaska, Aleutian Islands, Bering Sea Islands, Bering Sea Mainland, Chukchi Sea, Beaufort Sea, and Interior Alaska. (Author)

Progress is reported on two tasks designed to develop remote sensing beach reconnaissance techniques applicable to benthic and beach intertidal zones. In Task1--whose goal is to develop remote sensing algorithms for important beach composition and physical parameters--results of radiative transfer model development and application are reported. The model calculates the radiance of a beach, given physical and compositional information. In Task 2--whose goal is to develop remote sensing algorithms for mapping of bottom features in the benthic zone--results of radiative transfer model calculations and an evaluation of the modified ratio algorithm (MRA) performance in scattering waters are presented. (Author)

This report presents results of a location intensive seasonal study of the beach fauna of a barrier island in Dare County, NoC. The study area includes the beach face from the margin of the swash zone to 60 meters offshore on the ocean beach and from the swash zone to 300 meters offshore on the sound beach. The dominant species on the ocean beach were Emerita talpoida, Scolelepis squamata, Donax sp., and Parahaustorius longimerus. Three communities were defined on the beach by a factor analysis of physical and biological parameters measured. The sound beach was also characterized by 3 distinct faunistic communities. The Scolecolepides community -- characterized by high densities of Scolecolepides viridis, Chironomid larvae, and Peloscolex sp. and the presence of Rangia cuneata -- extended from 90-140 m to at least 300 m offshore. The zone between the beach margin and the edge of the Scolecolepides community was characterized by the burrowing amphipod Lepidactylus dysticus. A small developing marsh community, characterized by higher organic content, higher temperatures, lower salinities, increased numbers of species and higher species densities was the third community on the site. Species diversities were low.

Dredge spoil has been successfully stabilized with plantings of North Carolina's dominant marsh grass, Spartina alterniflora (smooth cord grass). Benefits of stabilizing spoil with Spartina appear to be: (1) Short term--marsh grass slows erosion of spoil back into the waterways, thereby reducing need for frequent and costly dredging; and (2) Long term--areas covered with Spartina come to look like natural marshlands. Marsh provides a vital source of nutrients and food for many young fish and shellfish and is, therefore, important to fishery resources. Even though outwardly it looks like natural marsh, scientists aren't sure if spoil covered with Spartina has characteristics similar to nature's marsh beneath the surface. Natural marsh is habitat for animal life much of which is found nowhere else. Complex nutrient cycles involving the marsh fauna, sediments, grass, and overlying waters are also found only in natural marsh. The purpose of this research was to answer the general question: Does spoil covered with smooth cordgrass function similarly to natural marsh. Objectives were: (1) To determine what fauna are found in transplanted spoil; (2) To compare spoil and natural marsh fauna; (3) To determine if spoil will ever resemble that of the natural marsh; (4) If the answer to (3) is yes, to determine how long after spoil is deposited animal life in the new marsh will become similar to natural marsh fauna; and (5) To investigate how growth of Spartina may affect development of animal life. This research shows that planting Spartina on dredge spoil can lead to creation of salt marsh that resembles natural marsh., Report for the Sea Grant Program of North Carolina State Univ., Raleigh, Publication no. UNC-SG-74-15.