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Rapid development has fragmented Singapore’s coastal habitats and converted them into artificial shorelines, with implications for the ecosystem services they provide. This study investigated the impact of urban development on two ecosystem services related to fisheries (direct provisioning and indirect nursery functions) by comparing adjacent mangrove and artificial rocky shore sites at two locations. In terms of fisheries provisioning ecosystem services, fish video data indicated that fish assemblage structure was significantly different between the two habitat types, with Ellochelon vaigiensis , Ambassis kopsii , Ambassis interrupta , and Zenarchopterus buffonis contributing most significantly. Trap data indicated that there were significantly more fish on the artificial rocky shore than mangrove at one of our locations in Pasir Ris. There were also significant differences in the size distribution of fish between habitat types at both locations, with high proportions of smaller fish in the mangroves. Even with higher juvenile presence, the role of urban mangroves in providing nursery ecosystem services is less clear, since we cannot determine whether this habitat type is essential for any individual fish species. This study indicates that mangroves provide a level of fisheries ecosystem services as part of a heavily developed and fragmented landscape in conjunction with other substrate types.

The abundance and biomass of benthic foraminifera are high in intertidal rocky‐shore habitats. However, the availability of food to support their high biomass has been poorly studied in these habitats compared to those at seafloor covered by sediments. Previous field and laboratory observations have suggested that there is diversity in the food preferences and modes of life among rocky‐shore benthic foraminifera. In this study, we used the stable nitrogen isotopic composition of amino acids to estimate the trophic position, trophic niche, and feeding strategy of individual foraminifera species. We also characterized the configuration and structure of the endobiotic microalgae in foraminifera using transmission electron microscopy, and we identified the origin of endobionts based on nucleotide sequences. Our results demonstrated a large variation in the trophic positions of different foraminifera from the same habitat, a reflection of endobiotic features and the different modes of life and food preferences of the foraminifera. Foraminifera did not rely solely on exogenous food sources. Some species effectively used organic matter derived from endobionts in the cell cytoplasm. The high biomass and species density of benthic foraminifera found in intertidal rocky‐shore habitats are thus probably maintained by the use of multiple nitrogen resources and by microhabitat segregation among species as a consequence. Diverse trophic ecology in microhabitat of coralline algae can be demonstrated by the compound‐specific stable nitrogen isotope analysis of amino acids and estimation of trophic position shown in this study. We confirmed a large variation in the trophic positions of different foraminifera from the same habitat, a reflection of endobiotic features and the different modes of life and food preferences of the foraminifera. The high biomass and species density of benthic foraminifera found in intertidal rocky‐shore habitats are thus probably maintained by the use of multiple nitrogen resources and by microhabitat segregation among species as a consequence.

Prosorhochmidae, known as smiling worms, are hoplonemerteans of great interest to nemertologists, since some species display viviparity and hermaphroditism, both rare traits in this phylum, and can be found in terrestrial and marine environments. Prosorhochmus is a predominantly marine genus and was never recorded on the Brazilian coast. The present study documents the first record of the oviparous Prosorhochmus belizeanus, along with population genetic diversity analyses. Here, we sequenced cytochrome c oxidase subunit 1 (COI) and 16S ribosomal RNA (16SrRNA) regions from individuals of three localities along the Brazilian Northeast coast. From these analyses, we found moderate genetic diversity, no genetic structuring, and no clear geographical pattern. In addition, migration analysis evidenced some influence of the Brazilian Current in the species’ dispersion. Those findings indicate colonization by a small number of mtDNA lineages followed by population stability and shed light into the importance of deepening the knowledge about those organisms to elucidate genetic and dispersion patterns of oviparous invertebrates of rocky shores.

Marine infrastructures are increasing, generating a variety of impacts and introducing artificial habitats which have low ecological value and support assemblages that differ significantly from those on natural rocky coasts. While in the past there was little ecological consideration as to how artificial structures were built, now the trend is to look for “greener” designs inspired by or mimicking nature. These greening efforts have had a strong focus on enhancing physical habitat structure to support more diverse assemblages, driven by the untested assumption that artificial habitats lack the physical structure proper to natural habitats. We tested this assumption by comparing five descriptors of physical structure (inclination; exposure; roughness; abundance, and diversity of surface morphological microelements) across a combination of natural and artificial habitats of regular and irregular morphologies (seawalls = artificial regular; cliffs = natural regular; breakwaters = artificial, irregular; and boulder fields = natural irregular) in the North Adriatic Sea. Most structural descriptors were similar between artificial and natural habitats. Only inclination was consistently steeper in the artificial than in the natural habitats. Other minor differences in roughness or in the abundance of some surface microelements were related to the general morphology (regular or irregular) of the habitat rather than to its artificial or natural identity. The outcomes challenge the widespread assumption that artificial habitats lack the physical structure proper to natural habitats and stimulate renewed consideration about other structural and non-structural elements that could enhance the performance and sustainability of artificial marine structures, such as construction material, environmental setting or maintenance. They also encourage a wider reflection about what makes an artificial building surface “greener”: structural complexity is an important ecological parameter, and its deliberate increase will lead to responses in the biota, however, this may not necessarily match “more natural” conditions.

Lavaud, L.; Pezerat M.; Coulombier, T.; Bertin, X., and Martins, K., 2020. Hydrodynamics on a rocky shore under moderate-energy wave conditions. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1473-1479. Coconut Creek (Florida), ISSN 0749-0208. Wave hydrodynamics on rocky shore platforms can be different from that on sandy beaches, namely due to a higher bed roughness. This study investigates short and infragravity waves transformation on a A-type rocky shore platform under moderate-energy wave conditions. Seven pressure sensors and two current meters were deployed along a cross-shore transect topped by a steep sandy beach. Data analysis complemented with a 1D model of energy flux conservation for short and infragravity waves reveals that commonly used value for the bottom drag coefficient has to be multiplied by 20 to match the field observations. Incoming infragravity waves suffer a strong dissipation at low tide due to bottom friction, while a slight shoreward increase is observed at high tide. Further analysis shows that, at this tidal stage, infragravity waves are almost fully reflected.

The collapse of macroalgal habitats is altering the structure of benthic communities on rocky shores globally. Nonetheless, how the loss of canopy-forming macroalgae influences the structure of epilithic microbial communities is yet to be explored. Here, we used experimental field manipulations and 16S-rRNA-gene amplicon sequencing to determine the effects of macroalgal loss on the understory bacterial communities and their relationship with epiphytic bacteria on macroalgae. Beds of the fucoid Hormosira banksii were exposed to different levels of disturbance resulting in five treatments: (i) 100% removal of Hormosira individuals, (ii) 50% removal, (iii) no removal, (iv) a procedural control that mimicked the removal process, but no Hormosira was removed and (v) adjacent bare rock. Canopy cover, bacterial communities (epilithic and epiphytic) and benthic macroorganisms were monitored for 16 months. Results showed that reductions in canopy cover rapidly altered understory bacterial diversity and composition. Hormosira canopies in 50% and 100% removal plots showed signs of recovery over time, but understory epilithic bacterial communities remained distinct throughout the experiment in plots that experienced full Hormosira removal. Changes in bacterial communities were not related to changes in other benthic macroorganisms. These results demonstrate that understory epilithic bacterial communities respond rapidly to environmental disturbances at small scales and these changes can be long-lasting. A deeper knowledge of the ecological role of understory epilithic microbial communities is needed to better understand potential cascading effects of disturbances on the functioning of macroalgal-dominated systems.