Search Results (98)

Mapping coastal landforms is critical for the sustainable management of ecosystems influenced by both natural dynamics and human activity. This study investigates the application of Transformer-based semantic segmentation models for pixel-level classification of key surface types such as water, sandy shores, rocky areas, vegetation, and built structures. We utilize a diverse, multi-resolution dataset that includes NAIP (1 m), Quadrangle (6 m), Sentinel-2 (10 m), and Landsat-8 (15 m) imagery from U.S. coastlines, along with high-resolution aerial images of the Greek coastline provided by the Hellenic Land Registry. Due to the lack of labeled Greek data, models were pre-trained on U.S. datasets and fine-tuned using a manually annotated subset of Greek images. We evaluate the performance of three advanced Transformer architectures, with Mask2Former achieving the most robust results, further improved 11 through a coastal-class weighted focal loss to enhance boundary precision. The findings demonstrate that Transformer-based models offer an effective, scalable, and cost-efficient solution for automated coastal monitoring. This work highlights the potential of AI-driven remote sensing to replace or complement traditional in-situ surveys, and lays the foundation for future research in multimodal data integration and regional adaptation for environmental analysis. Full article

Accurate nearshore bathymetry is essential for various marine applications, including navigation, resource management, and the protection of coastal ecosystems and the services they provide. This study presents an approach to enhance the accuracy of bathymetric estimates derived from high-spatial- and high-temporal-resolution optical satellite imagery. The proposed technique is particularly suited for multispectral sensors that acquire spectral bands sequentially rather than simultaneously. PlanetScope SuperDove imagery was employed and validated against bathymetric data collected using a multibeam echosounder. The study area is the Gulf of Sciacca, located along the southwestern coast of Sicily in the Mediterranean Sea. Here, multibeam data were acquired along transects that are subparallel to the shoreline, covering depths ranging from approximately 7 m to 50 m. Satellite imagery was radiometrically and atmospherically corrected and then processed using a simplified radiative transfer transformation to generate a continuous bathymetric map extending over the entire gulf. The resulting satellite-derived bathymetry achieved reliable accuracy between approximately 5 m and 25 m depth. Beyond these limits, excessive signal attenuation for higher depths and increased water turbidity close to shore introduced significant uncertainties. The innovative aspect of this approach lies in the combined use of spectral averaging among the most water-penetrating bands, temporal averaging across multiple acquisitions, and a liquid-facets noise reduction technique. The integration of these multi-layer inputs led to improved accuracy compared to using single-date or single-band imagery alone. Results show a strong correlation between the satellite-derived bathymetry and multibeam measurements over sandy substrates, with an estimated error of ±6% at a 95% confidence interval. Some discrepancies, however, were observed in the presence of mixed pixels (e.g., submerged vegetation or rocky substrates) or surface artifacts. Full article

This article documents abrupt lower distribution limits of sessile invertebrates and seaweeds from rocky intertidal habitats on Pacific and Atlantic shores from both hemispheres. The common feature of these striking patterns is that they are caused primarily by slow-moving predators or herbivores coming from lower elevations. This contribution aims at stimulating comparative studies on these fascinating systems as well as providing visual materials of educational value. Full article

Macroalgae provide key ecosystem services, forming habitats such as kelp and fucoid forests, rhodolith beds, and coralline reefs that sustain high biodiversity. However, multiple stressors, including climate change, harmful fishery practices, and pollution and coastal urbanization are driving macroalgal diversity loss and changing species composition and abundance. This study aims to assess macroalgal representativeness, richness and endemism in 16 Marine Protected Areas (MPAs), including four oceanic islands, and test if macroalgal assemblages in MPAs are distributed along a latitudinal gradient (0–29° S) in the Southwest Atlantic. To investigate the processes underlying community patterns, β-diversity was decomposition turnover and nestedness components. The complexity of taxonomic structure was measured by taxonomic distinctness. Overall, the studied MPAs comprised 695 macroalgal taxa, about 69% of Brazilian taxa, and 36% of the endemics. Rhodophyta were dominant (449 species) in most studied areas, except at Trindade and Martim Vaz Archipelago MPA, followed by Chlorophyta (158 species) and Ochrophyta (88 species). Macroalgal species composition in MPAs varied with latitude, and not with area size. They were continuously distributed across northeastern, eastern and southeastern Brazil and oceanic island ecoregions, between Fernando de Noronha (3° S) and São Paulo Litoral Norte (23° S) MPAs. Macroalgal diversity dissimilarity among MPAs was 92%, dominated by the turnover component (88%) and nestedness as a minor component (4%), indicating that dissimilarities are mainly driven by the replacement of species, rather than a gradual loss or gain of species. Effective protection of these MPAs should be prioritized as they harbor highly diverse, unique, and heterogeneous macroalgal assemblages along the SWA, surrounded by heavily impacted areas. Assessment of human impacts on macroalgal habitats in MPAs would contribute to defining effective management actions. Mid- and offshore shelf macroalgal habitats, particularly rhodolith beds, which harbor rare kelp species and mesophotic reefs, remain underprotected, and should be integrated into marine spatial planning for biodiversity conservation. Full article

The Portuguese Atlantic continental coast serves as a biogeographic transition zone where numerous macroalgal species reach their distribution limits, making it an especially intriguing area for studying shifts in species distribution. This region features sandy beaches and rocky outcrops that serve as habitats for a diverse range of organisms, including macroalgae. This illustrated guide aims to provide a simple and accessible overview of some of the most representative macroalgae species found along this coastline, specifically those designed for non-specialists in seaweed identification. Rather than offering a detailed identification key, the guide introduces key aspects of macroalgae—such as pigment composition, taxonomic classification, morphology, branching types, habitat on rocky shores, and potential human uses—in a clear and approachable format. Each species is accompanied by a photographic image, a general morphological description, and information about its typical habitat. Additionally, icons indicate whether a species has potential human applications or is considered non-indigenous. Species are categorized into green, brown, or red macroalgae based on their color and morphological characteristics. Full article

Citizen science is not only a participatory means of contributing to scientific knowledge but also an effective approach to addressing a wide range of societal challenges. Integrating citizen science with sustainability entails leveraging public engagement in scientific research to promote sustainable practices and advance the United Nations 2030 Agenda for Sustainable Development Goals (SDGs). The degree of public participation can influence the learning outcomes achieved. This study investigated the benefits and limitations of a co-creation citizen science approach implemented in a school context for monitoring species distribution on rocky shores, aligned with SDGs 4, 13, and 14. A mixed-methods design was applied, combining questionnaires administered to students (n = 100); participant observations of students, teachers, and researchers; and the analysis of observations submitted by one class (C2) to the iNaturalist platform. Students recorded 21 valid observations representing 13 different taxa, and developed skills such as critical thinking, problem-solving, collaboration, and interpersonal communication. They also recognised the potential of co-creation as a means of addressing scientific questions. However, teachers reported constraints in implementing the project, notably the breadth of the school curriculum and the lack of local support. This study reinforces the potential of co-creation citizen science projects to foster sustainable education. Full article

Invasive species can alter community composition and ecosystem functioning. In the subtidal rocky shores of Arraial do Cabo Bay, southeastern Brazil, the invasive coral Tubastraea spp. has established populations, raising concerns about long-term impacts on native benthic communities. This study investigates temporal shifts in β-diversity across 44 fixed plots containing Tubastraea spp., monitored over 383 days. Underwater photographic surveys and multivariate analyses identified nine distinct benthic community types, each forming mosaic structures of sessile organisms. Temporal β-diversity analyses revealed that only the group characterized by Tubastraea, crustose calcareous algae and the zoantharian Palythoa caribaeorum showed significant differences between species gains and losses over time, suggesting temporal-scale dependency. Key contributors to community dissimilarity included P. caribaeorum, crustose calcareous algae, turf, the sponge genus Darwinella, and Tubastraea. This study highlights the importance of considering both spatial and temporal heterogeneity when assessing the ecological impact of marine invasive species. Our findings underscore the need for multi-scale monitoring to fully understand the dynamics of tropical subtidal ecosystems under biological invasion. While numerous studies report a correlation between Tubastraea abundance and shifts in ecological diversity, this relationship may be weak, as critical drivers such as the complexity of community organization are rarely accounted for. Full article

Understanding habitat use in sympatric species is key to informing conservation efforts. Lontra felina and L. provocax are semi-aquatic mustelids commonly known as South American marine and southern river otters, respectively, that occupy contrasting coastal environments in southern Chile. We investigated habitat characteristics associated with sightings of both species in the Raúl Marín Balmaceda Multiple Use Protected Area, northern Chilean Patagonia. Our results show L. felina is restricted to exposed, steep rocky shores with sparse vegetation and intertidal belts dominated by Durvillaea antarctica and Lessonia spp., while L. provocax was found to be associated with sheltered, forested margins and estuarine areas dominated by Macrocystis pyrifera and other meadow-forming algae. Records did not show coexistence of both species in the same location; therefore, it is concluded that they exhibit a sympatric but non-syntopic pattern. Full article

The Strait of Sicily represents a biogeographically rich and complex region. The diverse geological origin and past continental connection of its islands have shaped a highly heterogeneous fauna, mainly composed of both African and European taxa. The Italian sea-slater, Ligia italica (Fabricius, 1798), is a small isopod inhabiting rocky shores of the Mediterranean Sea, Black Sea, and Atlantic Ocean. Despite its wide distribution, the phylogeography of this species is poorly understood, with limited available data suggesting a remarkable level of cryptic diversity. In this study, we investigated the mitochondrial genetic diversity (COX1) of L. italica across nine Italian and Maltese islands across the Strait of Sicily, aiming to clarify the biogeographic patterns underlying the distribution of these insular populations. Our results reveal an unexpectedly high genetic diversity within our study area, with eight different haplogroups, each characterized by low internal genetic variation and mutual distances ranging from 5.5% to 17.9%. These values are comparable to those associated with species-level rank within the genus Ligia. Overall, the phylogenetic relationships between the lineages appear well supported; however, the same relationships are not clearly correlated with geographic proximity or connectivity among the sampled localities. The distribution patterns of some of the detected haplogroups suggest possible passive dispersal mechanisms (e.g., rafting), while others indicate more intricate biogeographic scenarios. The overall diversity of L. italica within the Strait of Sicily, as well as the unclear origin of some insular populations, cannot be fully explained with the current data. In particular, the high genetic structure observed within the Maltese Archipelago, may partially reflect human-mediated dispersal (e.g., maritime transport), possibly involving source populations that remain unsampled or genetically uncharacterized. Our results highlight that the Strait of Sicily can be considered a diversity hot spot for L. italica and support the designation of this taxon as a putative species complex, with a cryptic diversity worthy of an exhaustive taxonomic revision. Full article

Here, we confirm the presence of two species of caridean shrimps for the first time in Brazil: Latreutes parvulus and Ambidexter cochensis. During active samplings conducted in December 2023, April 2024 and September 2024 on the rocky shore of Prainha da USP (Ubatuba municipality, São Paulo state, southeastern Brazil), we captured five ovigerous females of L. parvulus and fifteen individuals of A. cochensis (five males, three non-ovigerous females and seven ovigerous females). All the females of L. parvulus exhibited eyestalks with small, truncated processes separating the cornea from the stalk, a unique feature of this species. On the other hand, all specimens of A. cochensis exhibited a unique combination of characteristics: a rostrum with an apex bifid, a stylocerite bearing a lateral spinule and a transverse row of setae between the anterior pair of spines, and three longitudinal rows of setae on the telson. Also, males of A. cochensis had the tip of their appendix masculina armed with four simple apical setae and another two setae positioned below them. All analyzed shrimps had fully developed gametes in their reproductive systems, indicating breeding populations in this area. This is the first record of L. parvulus on the Atlantic coast of South America and a new meridional distribution limit for A. cochensis. Full article

The infraclass Euthyneura (Mollusca, Heterobranchia) exhibits significant diversity in morphology, size, life habits, and color. Several species are important for research in evolution, ecology, chemistry, and pharmacology. Despite Colombia’s expansive Pacific and Caribbean coasts, which host ecosystems such as rocky shores and coral reefs, key habitats for sea slugs and sea hares, the biodiversity of Euthyneura remains largely understudied. This study aims to expand the inventory of Euthyneura diversity in intertidal and shallow subtidal rocky and coral reef environments in Colombia’s Pacific (Uramba Bahía Málaga National Natural Park) and Caribbean (Seaflower Biosphere Reserve) areas. Rapid biodiversity assessments using snorkeling and errant scuba diving at depths of 1–40 m resulted in the documentation of 31 species (14 in Caribbean coral reefs and 17 in Pacific intertidal and shallow subtidal rocky shores and reefs). Eleven species were new records. The family Aplysiidae was the richest with five species, followed by Facelinidae with four, and Aeolidiidae, Discodorididae, Chromodorididae, and Plakobranchidae with three each. Given the limited sampling effort (~40 h in the Caribbean and ~20 h in the Pacific) and the substantial new data collected, it is evident that there is still much to learn about this group in these areas. Increased efforts, combined with detailed morphological and molecular techniques, will enhance our understanding and documentation of Euthyneura diversity in Colombia. Full article

The kelp Undaria pinnatifida is considered one of the 100 worst invasive species in the world. The presence of Undaria in Portugal was reported more than 20 years ago, but there is not recent detailed information about its distribution and impacts. The aims of this study are to provide updated data about the distribution of Undaria in marinas and natural habitats along the north Portuguese coast, to afford insights about Undaria impacts on native macroalgae and to test the efficiency of mitigation actions based on Undaria removal. Mitigation measures were implemented in a marina where a native kelp was recently displaced by Undaria. The results showed stable populations of Undaria in marinas, but few ephemeral ones on natural rocky shores. The observed distribution pattern suggests an important role of salinity and wave exposure in shaping the distribution of Undaria. Moreover, Undaria was able to displace a native kelp and overgrow mussels in marinas, while on natural rocky shores, it was able to overgrow Gongolaria baccata but not native kelps. Finally, mitigation actions resulted in a partial recolonization by the native kelp. Full article

The present study aimed to describe the reproductive cycle of the black-footed limpet (Patella depressa Pennant, 1777) from an intertidal rocky shore on the Algarve coast (southern Portugal). Samples were collected monthly between January 2017 and December 2018, with the species’ gametogenic cycle being described based on gonad histology and the mean gonadal index. The presence of both transitional and mosaic hermaphrodites indicates that some individuals are able to change sex (sequential hermaphroditism). Despite the occurrence of hermaphroditism, sex proportions were approximately equal, suggesting the absence of protandric sex change in this species. The population exhibited an extensive occurrence of ripe and spawning gonads throughout almost the whole study period, probably related to consecutive processes of gonadal re-ripening and partial spawning events. The reproductive dynamics of P. depressa displayed clear inter-annual differences, with a short resting period recorded in 2017 (June–August) and the absence of resting gonads in 2018. The continued monitoring of this population and collection of environmental data are required to further improve knowledge of the reproductive dynamics of this species. Such information is crucial for proposing additional management measures for the sustainable harvesting of limpets in southern Portugal. Full article

This study investigates the diversity and distribution of intertidal Cystoseira sensu lato (s.l.) species across different protection zones within the “Capo Gallo-Isola delle Femmine” Marine Protected Area (MPA) in the central Mediterranean Sea. Five Cystoseira s.l. species (Cystoseira compressa, C. foeniculacea, Ericaria amentacea, E. brachycarpa and E. crinita) were observed on the intertidal rocky shores, with varied abundances across the MPA’s protection zones. Ericaria amentacea was the only species found in all zones, with a much higher cover percentage in the most protected area (zone A). However, its morpho-functional traits showed an inverse trend, with the largest thalli found in the moderately protected zone B and C. The remaining Cystoseira s.l. species were only found in zones B and C probably due to their wider area and greater habitat diversity compared to zone A. The presence of two non-indigenous species, Asparagopsis taxiformis and Caulerpa cylindracea, was observed exclusively in the less protected zones B and C. Our findings highlight the complex interactions between MPA protection levels and Cystoseira s.l. species conservation, with protection having, in some respects, a positive influence on selected Cystoseira s.l. species, indicating the importance of careful consideration in MPA design and management. Furthermore, this study provides a baseline for future monitoring of Cystoseira s.l. populations in light of ongoing environmental changes in the Mediterranean Sea. Full article

When a species is introduced in a new location, it is common for it to establish itself when it finds favorable conditions in the receptor community with regard to interspecific interactions with native species. The azooxanthellate corals Tubastraea coccinea and Tubastraea tagusensis are invasive species introduced in the Caribbean Sea, the Gulf of Mexico, and the Brazilian Southwest Atlantic. They are successful competitors for space, have multiple reproductive modes, and have high larval dispersion and recruitment, but studies on food and trophic relationships of the genus Tubastraea are still scarce. In the present study, we used isotopic values of δ¹³C and δ¹⁵N to investigate trophic relationships in rocky shore communities invaded by T. tagusensis and T. coccinea corals under different oceanographic and anthropogenic contexts. Using metrics derived from the isotopic values, we show that invaded communities have a lower degree of trophic diversity, with species characterized by similar trophic ecologies while abiotic factors seem to contribute to the biotic resistance of communities exposed to invasion events. Tubastraea spp. occupy a niche space similar to that occupied by the native community of suspension feeders, sharing resources already consumed by the receptor community, which makes invading corals successful competitors for food. Full article