Small Reefs Research Articles

Defining the role of Sabellaria alveolata reefs as nursery areas for juvenile fish: first evidence from drone-based imagery and underwater visual census data

The biogenic reefs built by the honeycomb worm Sabellaria alveolata constitute priority habitats along Atlanto-Mediterranean coastal areas. Despite their wide extent and important ecological role, the nursery value of S. alveolata reefs remains unclear, and more information is needed to define how such structured habitats affect juvenile fish assemblages. In this study, habitat use by juveniles of 7 fish species was investigated by underwater visual census (UVC) at 3 study sites representing a gradient of complexity of Sabellaria reef habitats, spanning from a large and uniform reef to patchy and isolated small reef formations. Sabellaria reef metrics derived by drone-based cartography and GIS analysis were used to quantitatively monitor the seasonal structural changes occurring due to the natural dynamics of the reefs. We also tested the potential effect of Sabellaria habitats on the growth and relative condition factor (Kn) of white seabream Diplodus sargus juveniles. Five of the 7 surveyed species, especially sparid fishes, showed a clear preferential association with Sabellaria formations. Generalized additive modelling revealed a significant effect of the compactness ratio on estimated fish densities at high and low index values. The juvenile fish sampled on Sabellaria reefs exhibited higher values of Kn than those sampled on rocky habitats, supporting the hypothesis that structural complexity positively affected their condition. We provide evidence on habitat use by juveniles, suggesting that the presence of the Sabellaria reef may act as a nursery and affect local fish density in Mediterranean coastal waters.

The vertical distribution of fish on two offshore oil platforms

Knowledge of platform ecology is necessary to best inform decommissioning practice. Remotely operated vehicle (ROV) video is often collected during standard industry operations and may provide insight into the marine life associating with offshore platforms, however, the utility of this video for ecological assessments remains unclear. Archival ROV video surveys at the Wandoo oil platforms on Australia’s North West Shelf was evaluated for its utility, with only 4.9% of imagery usable for standardised ecological studies. Based on the subset of usable ROV video, the influence of depth and structural complexity on attributes of the fish assemblage on the Wandoo oil platforms was examined. Vertical ROV transects on three vertical shafts on the Wandoo platforms were stratified into 10 m depth strata from 0 to 50 m, with 111 fish taxa from 25 families identified and counted across all depth strata. At both platforms, taxonomic richness and abundance was significantly highest in shallow regions and declined with depth. Small reef fish were predominantly associated with structurally complex habitat in shallow regions (<22 m), whilst large demersal species dominated below 32 m. Future decommissioning policy in Australia should consider the vertical fish distributions and the importance of shallow sections of platforms. Finally, the dearth of usable video was due to the haphazard method of collection and it is recommended that future surveys should be conducted according to scientific standards to ensure greater utility of the video for both industry use and scientific research.

Underwater macrophotogrammetry to monitor in situ benthic communities at submillimetre scale

Abstract Larval settlement and recruitment of sessile organisms are key ecological processes for population recovery and maintenance that occur at scales invisible to the human eye. Accordingly, proxies of recruitment have commonly been quantified using artificial substrata such as settlement tiles made of diverse materials and shapes, which are typically transported to the laboratory for examination. However, it is unknown how much bias is introduced with this sampling strategy and how recruitment quantified on tiles relates to recruitment on nearby natural substrata. Here, we applied techniques that combine macrophotography with photogrammetry (macrophotogrammetry) underwater to monitor benthic communities at submillimetre scale. This application allows the investigation of recruitment and community succession of the earliest life‐history stages in situ and on natural substrata. We tested the use of four different imaging systems, varying in costs from US$ 1400 to US$ 5440. While the most expensive SONY αRiv system provided the best visual output and ground resolution (up to 5 μm/pixel with a + 4 close‐up lens); regardless of systems, 3D models always had a ground resolution ≤23 μm/pixel and errors in planar measurements of submillimetre features were similar among systems. This level of resolution compares well with stereomicroscopy in the range of 5:1 to 10:1 magnification, while providing detailed 3D digital records through time. Using a coral reef example, we apply this approach to demonstrate how it can be used to monitor small reef areas (~300–600 cm2) through time, including the quantification of biophysical metrics such as cover of small facilitative and competitive organisms and microhabitat complexity. We further show that organisms as small 0.5 mm in size, such as 2‐month‐old coral settlers, can be located accurately within the 3D models and measured with a good level of confidence. This method can be readily applied to other benthic environments to elucidate drivers of early recruitment and recovery of benthic organisms following disturbance impacts at very fine scales, directly on natural substrata, to avoid biases inherent with laboratory‐based analyses of artificial surfaces.

Localising terrestrially derived pollution inputs to threatened near-shore coral reefs through stable isotope, water quality and oceanographic analysis

Near-shore coral reefs are at high-risk of exposure to pollution from terrestrial activities. Pollution impacts can vary with site-specific factors that span sources, rainfall and oceanographic characteristics. To effectively manage pollution, we need to understand how these factors interact. In this study, we detect terrestrially derived nutrient inputs on near-shore reefs at Norfolk Island, South Pacific by analysis of dissolved inorganic nitrogen (DIN) and stable isotopes. When compared to a reef site with predominantly oceanic inputs, we found that both the lagoon and a small reef adjacent to a catchment have signatures of human-derived DIN shown through depleted δ15N signatures in macroalgae. We find pollution exposure of reef sites is associated with known and unknown sources, rainfall and mixing of water with the open ocean. In characterising exposure of reef sites we highlight the role of site-specific context in influencing pollution exposure for benthic communities even in remote island systems.

An experimental study on oscillatory characteristics of young mangroves behind a portable reef

ABSTRACT Approximately half of the world’s mangroves are concentrated in Asia, but they have been logged at an alarming rate. To compensate for this, mangrove plantations are being attempted at various sites but with many failures. In this study, we investigated the role of a small portable reef in protecting young mangrove plants from hydrodynamic disturbances caused by short-period waves. To investigate the effectiveness of such a small reef, an experiment using a large wave flume was conducted with two types of real-sized portable reefs (stone and block reefs). A numerical wave model was also constructed to analyze in detail the turbulence around the reef. Our previous study showed that short-period waves can cause resonant oscillations in young mangrove plants. To confirm whether this occurs even behind a reef system, a young mangrove model made of flexible olefin resin was tested with a small wave flume placed behind porous and non-porous reefs, and its oscillation was precisely measured using a high-speed camera. These experiments yielded several new findings. If appropriately designed, small porous reefs can minimize oscillations with adverse effects and provide a favorable environment for the initial growth of mangroves at restoration sites.

Aquatic Walking and Swimming Kinematics of Neonate and Juvenile Epaulette Sharks.

The epaulette shark, Hemiscyllium ocellatum, is a small, reef-dwelling, benthic shark that-using its paired fins-can walk, both in and out of water. Within the reef flats, this species experiences short periods of elevated CO2 and hypoxia as well as fluctuating temperatures as reef flats become isolated with the outgoing tide. Past studies have shown that this species is robust (i.e., respiratory and metabolic performance, behavior) to climate change-relevant elevated CO2 levels as well as hypoxia and anoxia tolerant. However, epaulette shark embryos reared under ocean warming conditions hatch earlier and smaller, with altered patterns and coloration, and with higher metabolic costs than their current-day counterparts. Findings to date suggest that this species has adaptations to tolerate some, but perhaps not all, of the challenging conditions predicted for the 21st century. As such, the epaulette shark is emerging as a model system to understand vertebrate physiology in changing oceans. Yet, few studies have investigated the kinematics of walking and swimming, which may be vital to their biological fitness, considering their habitat and propensity for challenging environmental conditions. Given that neonates retain embryonic nutrition via an internalized yolk sac, resulting in a bulbous abdomen, while juveniles actively forage for worms, crustaceans, and small fishes, we hypothesized that difference in body shape over early ontogeny would affect locomotor performance. To test this, we examined neonate and juvenile locomotor kinematics during the three aquatic gaits they utilize-slow-to-medium walking, fast walking, and swimming-using 13 anatomical landmarks along the fins, girdles, and body midline. We found that differences in body shape did not alter kinematics between neonates and juveniles. Overall velocity, fin rotation, axial bending, and tail beat frequency and amplitude were consistent between early life stages. Data suggest that the locomotor kinematics are maintained between neonate and juvenile epaulette sharks, even as their feeding strategy changes. Studying epaulette shark locomotion allows us to understand this-and perhaps related-species' ability to move within and away from challenging conditions in their habitats. Such locomotor traits may not only be key to survival, in general, as a small, benthic mesopredator (i.e., movements required to maneuver into small reef crevices to avoid aerial and aquatic predators), but also be related to their sustained physiological performance under challenging environmental conditions, including those associated with climate change-a topic worthy of future investigation.

Assessment method of the sea turtle-nesting habitat of small reef islands

The coral islets in the lagoon of New Caledonia are a major breeding and nesting site for various species. Many species reproduce and nest there, whether they are Chelonians (green turtles and loggerhead turtles), offshore seabirds (Procellariidae: shearwaters, petrels …) or more coastal (Laridae: terns, ospreys …) or sqamata (sea krait: Laticauda saintgironsi and Laticauda laticaudata). These species are dependent on the persistence of the islets in which they find the necessary conditions for nesting. Previous research has shown that these islets can evolve very rapidly at a yearly to decadal timescale. These geomorphological evolutions lead to surface area variations as well as geomorphological, topographical and land cover changes. These changes may lead to an evolution of the sea turtle nesting habitat: reduction of suitable areas for nesting and changes of the accessibility to the nesting sites. The goal of our work is to propose a method that allows to determine, map and quantify the more or less favourable character of the islets coasts to the nesting of sea turtles. Using several parameters, an indicator of the nesting attractiveness of coast is constructed and mapped. This method was applied to 13 coral islets in the southern lagoon of New Caledonia. Comparison of the results with the location of sea turtle nests acquired during the 2020 campaign attest the relevance of the method.

Ecosystem engineering kelp limits recruitment of mussels and microphytobenthic algae

Ecosystem engineers often exert strong effects on the recruitment of other species through modification of the local abiotic and biotic environment. In 2015, artificial reefs in eastern Tasmania (− 42.64693, 148.01481) spanning seven different patch sizes (0.12–7.68 m2) and supporting four densities of transplanted kelp (Ecklonia radiata at 0, 4.1, 8.2 and 16.4 kelp m−2) were used to determine how the patch size and density of this ecosystem engineer influenced the recruitment of microphytobenthic (MPB) algae, and a secondary ecosystem engineer, the mussel Mytilus galloprovincialis. Increasing kelp density and patch size inhibited the establishment of subcanopy MPB algae on settlement slides and reduced the recruitment of mussels in standardised rope fibre habitats (RFHs). The productivity:biomass ratio (P:B) of mussel recruits tended to be lower on small reefs and reefs without kelp, relative to larger reefs with high densities of kelp. Canopy shading and reduced cover of turf algae appeared to negatively impact the recruitment of MPB algae and mussels, whilst reduced sediment accumulation on the reefs due to the kelp was also negatively associated with mussel recruitment. These findings highlight the role of ecosystem engineering by kelp in inhibiting the establishment of other species which may additionally impact community dynamics and primary and secondary productivity. The limited capacity of small kelp patches to inhibit the recruitment of other organisms supports the notion that fragmented patches of ecosystem engineers could be more suspectable to adverse outcomes from species interactions making them less resistant to shifts towards an alternative ecosystem state.

Influence of variability to coastline dynamic in the small uninhabited reef islands of Kepulauan Seribu

Small reef islands provide habitable land for coastal communities in many parts of the world. However, the small, low lying reef islands are commonly considered among the most geomorphically sensitive landforms to changes in sea level, wave processes, sediment supply and anthropogenic impacts. Kepulauan Seribu in the Java Sea comprise of numerous reef islands. By 2019, the islands chain is host to more than 24 thousand people. Kepulauan Seribu is affected by monsoon wind cycle. The monsoon wind also known to interact with an interannual phenomenon such as Indian Ocean Dipole (IOD) which affecting regional and local wind circulation. This study aims to examine the reef shoreline response to seasonal and interannual climate variability using satellite data that encompasses yearly monsoon cycle and IOD event. Strengthens (weakens) of winds speed in the study area during the East (West) Monsoon, which in some year also coincides with a positive (negative) IOD event, are observed from 2009 to 2018 ERA - Interim by The European Centre for Medium - Range Weather Forecasts (ECMWF) data. This variability influences the shoreline shifting in the uninhabited reef islands of Kepulauan Seribu as identified based on satellite imagery analysis. More pronounce shifted of large sediment flux are perceptible on opposing monsoon which coincides with positive/negative IOD event. Small uninhabited reef islands have ecological and economical value. Hence, enhancing coastal resilience from erosion by using conservation-types approach should be taking into consideration. Ultimately, a good understanding of climate variability that controlled changes in beach systems of reef islands is important for adequate coastal management decisions.

The role of the formation and destruction of the Hudson Strait glacial ice dam in changes of climate and sea level during the Last Interglacial-Glacial transition

During the Last interglacial period of constant sea level, large coral reefs formed on the tectonically rising island of Barbados, and a broad lagoon with a small barrier reef formed at the Cane Vale site. The constant sea level was ended by a rapid glaciation, causing a fall of world sea level of 2.4 m, as measured by surveys of features associated with breaking waves on Barbados. The fall began about 120 ka BP, and lasted roughly 400 years, according to a lake pollen record from western Europe. That rapid fall was terminated at a wave-cut step on Barbados and with a quite small reversal in falling sea level. The rise was caused by rapid melting of the marine-based Barents Sea ice dome and other ice masses, due to a restored strong Atlantic Meridional Overturning Circulation (AMOC) flow. The sea level fall then resumed until it was halted at a wave-cut step at a world sea level 12.3 m below the last interglacial level, as recorded at the University of the West Indies site on Barbados. Following the erosion of that second step, a zonal northern North Atlantic circulation prevailed, causing a glacial ice-volume decrease and rise in sea level of 3.8 m. These two sea level fall reversals were caused respectively by the formation and destruction of a Hudson Strait ice dam and the resulting increase and much later decrease in the rate of AMOC flow.

Long-term demographics of a coral-reef fish: growth, survival and abundance at several spatial scales

In marine organisms, pelagic larval dispersal often results in genetic panmixis among widely separated populations; however, local conditions may produce populations of marine organisms that differ in key life history traits. Here, we assess spatial differences in growth, body condition, survivorship and movement over a decade for lemon damselfish Pomacentrus moluccensis. Newly recruited fish were tagged on the southern (One Tree Island, 23°S), and northern Great Barrier Reef (Lizard Island, 15°S), 1200 km apart, and monitored for over a decade to provide direct data on growth and survivorship. New recruit physiological condition (lipid content) had a weak positive influence on early survival, but not on long-term persistence or growth, and the larval supply signal was lost after 2 years, suggesting post-settlement processes were key in long-term population persistence. Fish exhibited extreme site fidelity, with older/larger fish moving most (all less than 7 m). At Lizard Island, under 5% of individuals remained after 3 years, none after 4 years, while at One Tree Island 5% of individuals survived over 5 years, with 1% remaining after a decade, suggesting Lizard Island populations may require more frequent replenishment to persist. Among-site (within location) variation in mortality was high, and not related to density, suggesting local conditions such as wave exposure and predators were important. Surprisingly, mean growth at the two locations, which differ by around 2 °C on average in sea temperature, was practically identical, levelling off after 3 years, but with high variation among nearby sites within each location, which would affect size-based fecundity and time of first reproduction at these smaller spatial scales. Neither early post-settlement growth nor mortality were density-dependent, and early growth was not related to overall longevity. These small reef fishes are highly sedentary and some demographic parameters, but not others, differ at a range of scales, with post-settlement populations likely driven largely by mortality patterns at the larger spatial scale. Latitudinal and smaller-spatial scale differences in performance (growth, survival) of this species, leading to offsets in expected time to maturity an fecundity, are contrasted by evidence of stability of adult populations over two decades at One Tree Island, which suggests that resilience to environmental change/climate change and other externalities differ considerably across this species’ distribution.

Bioecology of coral reef in Panjang Island of Central Java Indonesia

Coral reefs currently are suffered from natural factors along with increasing anthropogenic activity. Panjang Island, a small reef island located in Jepara Regency, may also be experiencing such conditions. Therefore, this work was aimed to observe the condition of the coral cover of Panjang Island. Line intercept transect was applied to survey the coral cover and mortality index from fourteen stations. Insitu data consisted of the bottom substrate composition of the reefs and the physical parameters of the sea. The secondary data, i.e. coral reef area maps from 2001 to 2019 were taken from Landsat Image 7 and 8, data of wind were obtained from www.ogimet.com, while tidal data were collected from BMKG. The bathymetry was determined from the Geospatial Information Agency data, salinity global analysis forecast Phy 001.024 (CMEMS). Sea surface temperature (SST), and chlorophyll-a distribution were analyzed using ENVI software. The result showed that Panjang Island has a poor to the moderate condition of hard coral. Two out of six categories of abiotic and dead coral were found to be high. The mortality index of coral was in the high category (average 0.52). During research periods the sea waters were characterized by high sea surface temperature (29.34-30.94°C), chlorophyll-a was also tended to be high (0-2.65 mg.m-3), and an average of salinity was high 32 ‰. The weak currents came to all sides of the island, therefore the coral reef was not exposed to extreme currents. The waves came from the east, then the energy decreases after being blocked by coral reefs on the eastern side of the island, so that coral reefs in the northeast and south sides were safer to be exposed. The results suggest that hydrodynamic ecology directly or indirectly affected the percentage of coral cover and mortality index at the reefs of Panjang Island.

How a Small Reef in the Kuroshio Cultivates the Ocean

AbstractVertical nitrate fluxes associated with turbulent mixing and upwelling around a small reef in the Kuroshio are quantified by continuously deploying a turbulence microstructure profiler with an attached submersible ultraviolet nitrate analyzer while drifting from the upstream to the downstream of the reef. Flow separations and trains of Kelvin‐Helmholtz billows (thickness = 60 m) are identified using a shipboard ADCP and an echo‐sounder. The turbulence diffusivity associated with the vigorous turbulent mixing reaches up to O(10−1 m2 s−1), resulting in strong nitrate fluxes of O(1–103 mmol m−2 day−1). In addition, large differences between the upstream and downstream density profiles suggest a strong upwelling velocity of O(10−3 m s−1), as well as an upwelling nitrate flux of O(102 mmol m−2 day−1) in the entire subsurface layer.

Social organization variation and behavioural flexibility in the facultative cleaning goby Elacatinus prochilos

Social species often show intraspecific variation in the size and composition of their social units, i.e. the social organization. This variation represents a challenge for comparative studies trying to understand evolutionary transitions in social organization complexity. Most studies on intraspecific variation in social organization (IVSO) have focused on the environmental factors selecting for variation in social organization but the mechanisms underlying such variation remain relatively unexplored. Here we investigated the potential mechanisms giving rise to IVSO in the Caribbean cleaning goby Elacatinus prochilos . This small reef fish typically exhibits two types of social organization, pair living or group living, which not only differ in group size but also in feeding strategy and social behaviour. Pair-living gobies cooperatively feed on ectoparasites removed from larger visiting fish, while group-living gobies feed on microinvertebrates living inside sponges and aggressively defend the best feeding spots against each other. We tested how flexible the social organization, social structure and competition over a food source of E. prochilos are by experimentally manipulating group composition, habitat structure and feeding condition of pair-living and group-living wild adult gobies in laboratory. Despite having different original social organizations in the wild, both pair-living and group-living gobies formed dominance hierarchies and exhibited affiliative behaviours in our group manipulations. This indicates that IVSO in this species is not driven by pre-determined or early-developed mechanisms, but rather a consequence of flexibility in social organization, also known as social flexibility. • We investigated the mechanisms of social organization variation in E. prochilos. • We used a controlled group manipulation to test the behavioural flexibility of individuals. • Individuals exhibiting different social organizations in the wild converged in social behaviour. • This indicates that variable social organization is driven by social flexibility.

Intertidal mussel reefs change the composition and size distribution of diatoms in the biofilm

Migrating diatoms are microscopic ecosystem engineering organisms that have functional consequences on the seascape scale by significantly contributing to the microphytobenthos biofilm. The microphytobenthos biofilm is a thin photosynthesising layer that covers the sediment on intertidal flats. It fuels the food web, increases sediment stability, and enhances the deposition of particles, providing ecosystem services to coastal communities. Here we tested the effect of another ecosystem engineering habitat, intertidal blue mussel reefs, on the composition and properties of migrating diatom communities. Small-scale reefs constructed in the intertidal mimicked and reinforced the natural pattern in diatom community composition and function that we documented in the field. The field experiment adding small reefs to the intertidal ran from 30 April to 10 June 2015 and the field samples were collected around a natural blue mussel bed on the same tidal flat on 7 October 2015 (N 53.489°, E 6.230°). Both the constructed small-scale reefs and the natural reef changed the community composition of diatoms in the biofilm by promoting higher numbers of smaller-sized cells and species. Small diatoms have higher growth and gross photosynthesis rates, indicating that this explains the higher production and chlorophyll-a concentration of the biofilm measured on natural intertidal shellfish reefs. Our results showed that shellfish reefs have a large impact on biofilm functioning. However, biofilms are also fuel for the shellfish, indicating that the two very different ecosystem engineers may facilitate coexistence on tidal flats through a positive feedback loop.

Vital rates of small reef corals are associated with variation in climate

AbstractWith coral cover declining on most tropical reefs, efforts are intensifying to understand the mechanisms by which environmental stressors are driving populations into demographic deficit. Here, the population dynamics of sexual cohorts of small corals (≤ 4 cm diameter) in St. John, US Virgin Islands were used to test the hypothesis that the association of vital rates with environmental conditions has changed over 22 yr. The annual fate of 3999 corals at six sites and 7–9 m depth were used to populate Leslie Matrices and calculate assemblage growth rates (λ, without recruitment), mortality of the smallest corals, and graduation from the largest size class. Vital rates were tested for associations with temperature, the number of days with seawater warmer than 29.4°C (i.e., hot days), and rainfall. Transition probabilities varied among years, and usually more corals remained in their original size class than moved among size classes. Corals in the smallest size class had the highest mortality rate (42% yr−1), λ had a grand mean of 0.688, and there were trends for λ to vary with the number of hot days and rainfall through quadratic relationships. The linear dependence of λ on rainfall over consecutive 3‐yr periods declined over two decades, suggesting that this colony size‐defined coral assemblage has undergone phenotypic change in their responsiveness to varying environmental conditions.

Abundance and distribution of the invasive polychaete Ficopomatus enigmaticus in three South African estuaries

Ficopomatus enigmaticus (Fauvel 1923) is a reef-building serpulid polychaete that is found in warm and temperate estuaries across the globe. This ecosystem engineer causes ecological and socio-economic impacts in invaded systems through efficient filtering of the water column and the formation of large calcareous reefs. As such it is important to monitor F. enigmaticus invasions and track changes in distribution and abundance. Although recent genetic studies have highlighted cryptic sympatric species within invasions previously ascribed to F. enigmaticus the genetic status in South Africa remains unresolved. This study provides an assessment of the invasion by this tube worm in three estuaries of conservation importance in the Western Cape, South Africa. Through the use of historical data, the trajectories of these invasions were considered. Zandvlei Estuary supported the largest standing stock (29 194.22 kg) while Berg River Estuary supported only 3.39 kg. It was notable that in both estuaries the worm was almost totally confined to artificial substrata. Despite the presence of large intact reefs in Milnerton Lagoon, no live worms were recorded in 2019. Comparisons with historical data revealed that populations have declined in all three estuaries. These results highlight the need for routine monitoring of Ficopomatus populations. It is suggested that episodic removal of the small reefs from Berg River Estuary could minimise spread within the estuary and prevent the negative impacts known from elsewhere. Strategic removal from Zandvlei Estuary, and Milnerton Lagoon should the worm be detected again, could limit its negative impacts in these systems while retaining the benefit of enhanced water quality associated with this prolific filter feeder.

Paleocene-Lower Eocene carbonate platforms of westernmost Tethys

The Paleocene-lower Eocene succession is well exposed in Sierra Espuña-Mula Basin (Betic Cordillera, S Spain) and carbonate platforms are well represented as part of this succession. The study of the paleoenvironmental evolution of these platforms has allowed to cover an important gap in the knowledge in the westernmost Tethys. Thirteen microfacies (Mf1 to MF13) were recognized based mainly on the fossil assemblage (principally larger benthic foraminifera), texture and fabric of the microfacies. The fossiliferous assemblage of the entire succession shows a mixture of photozoan and heterotrophic biogenic elements, typical of an inner to outer ramp environment of a warm temperate biogeographic province. Fragments of hermatypic corals have also been detected in the lower part of the succession (Paleocene) allowing thinking in propitious conditions in this period. The succession evolves upwards (Lower Eocene) to low-energy shallow marine protected environments (lagoon) in inner ramp settings. In addition, abundant porcelaneous larger benthic foraminifera such as alveolinids and soritids are indicative of euphotic shallow marine conditions in moderately oligotrophic upper subtidal environments. In the upper part of the succession, hermatypic corals as displaced fragments and in situ isolated coral phaceloid colonies also appear together with other biogenic components indicating warm shallow and euphotic marine conditions (coral-maërl environment). Lenticular larger benthic foraminifera, characterizing marine mesophotic and oligotrophic habitats can be found in the upper part of the middle ramp, and flattened larger benthic foraminifera forms indicating lowermost mesophotic conditions in a distal middle ramp. The obtained results have been compared with other similar Tethyan sectors obtaining a broader view. The biogenic marine association is characterized by the absence of the ‘Lockhartia community’ of the Tethyan domain, together with the dominance of alveolinids, nummulitids and orthophragminids. During most of the Paleocene, northern Mediterranean Tethys platforms were located in the middle paleolatitudes and characterized by coral-reef and coralgal biofacies. The studied platforms (located at a latitude close to 25°N) show, in a ramp-like context, underdeveloped in situ coral constructions probably of patch-reef type. In the early Eocene the expansion and abundance of the larger benthic foraminifera and the practical disappearance of coral took place in the sedimentary platforms through the entire Tethys. However, in the study area small reef coral build-ups have also been observed in the lower Cuisian beds, indicating that in westernmost Tethys coral construction continued at these latitudes.

Parasites of Small Cryptic Coral Reef Fish from the South China Sea

Parasites in 61 individuals of eight species of coral reef fish (Caracanthus maculatus, Scorpaenodes sp., Sebastapistes cyanostigma, Gobiodon unicolor, Paragobiodon modestus, P. echinocephalus, Pseudocheilinus hexataenia, and Halichoeres sp.) were studied in April–May 2012–2014 and November 2017. All studied fish were symbionts of corals of the genera Acropora and Pocillopora. The parasites found were the nematodes Spirocamallanusistiblenii, Raphidascaris (?) sp., and Ascarophis sp., a larva of the cestode Nybelinia sp., as well as metacercariae of the trematodes Stephanostomum sp. 1, Stephanostomum sp. 2, and Trematoda gen. sp. The low prevalence, infection rate, and diversity of parasites could be related to low population numbers of fish hosts, their efficient individual anti-parasitic defense, as well as to predation by corals that prey on dispersal stages of parasites.

Experimental investigations on a portable atmospheric water generator for maritime rescue

Abstract To offer an alternative for supplying fresh water to people in distress in tropical seas before rescue or to garrison soldiers on a small reef, a portable solar-photovoltaic atmospheric water generator was designed and tested experimentally, and is composed of a water generating module, a water purifying module, a power supply and control module, and a buoyancy module. The results showed that the best water production rate of 460 mL/h was achieved when Tin = 27, RHin = 92%, Qa = 600 m3/h, with the desalination rate above 99.65%, proving itself a feasible solution as a portable desalination device. The daily water production can reach 5.52 L/d, which is more than twice the minimum quantity of the WHO drinking water standard (2.5 L/capita-day), and the energy consumption can be controlled under 200 W. The influences of major operating parameters on the device performance were analyzed and performance comparisons were carried out with the reported AWG products/prototypes. By integrating with a distress signal launcher and positioning module to shorten rescue time, the device has the potential to be employed as a small rescue platform for people in distress in tropical oceans, carried on board ship as a precaution.