Search Results (6)

Rhodoliths are calcareous red algae considered indicators of ocean acidification and key biodiversity hotspots due to their ability to host a variety of species within their three-dimensional structures. This work aims to review the available scientific literature on rhodolith-forming species: reports from literature, the Symbiota digital taxonomic inventory, field observations, and nucleotide databases. A total of 21 species is reported, predominantly from the Corallinaceae family and the Lithophylloideae subfamily. Rhodoliths have been reported in Bocas del Toro, the Gulf of Chiriqui, Coiba National Park (PNC), the Gulf of Panama, and at the Las Perlas Archipelago. This review represents the first step in raising awareness about the presence of these organisms along Panama’s coast and advocating for their inclusion in the management plans of protected areas, such as PNC, a UNESCO World Heritage Site, where rhodoliths are not yet part of the recorded algae species list or the park’s conservation targets, despite their ecological relevance. Knowledge remains limited, and their conservation status is uncertain, but the increasing sampling efforts and integration of morphological and molecular studies will open new opportunities to improve the estimation of rhodolith diversity in Panama. Full article

Polychaetes are important marine invertebrates that contribute to sediment bioturbation, nutrient recycling, and food web dynamics. This study examines the diversity and structure of the polychaete assemblages associated with the red algae Corallina officinalis in areas with different levels of anthropogenic pressures of the Northeastern Adriatic Sea. Sampling was performed in the intertidal zones. Altogether, 54 species from 13 families were found, with Syllidae being the most abundant. Polychaete richness, relative abundance and diversity at sampling locations with and without anthropogenic pressures showed no significant difference. Multivariate analyses revealed significant differences in species composition between sites under anthropogenic pressures and those without, with key species such as Sphaerosyllis pirifera, Syllis rosea, Syllis prolifera, Syllis gerundensis, and Platynereis dumerilii playing significant roles. Syllis rosea was the most abundant in locations without anthropogenic pressures, while S. pirifera was the most abundant in locations under anthropogenic pressures. These results suggest that while polychaete communities are resilient, anthropogenic pressures are causing shifts in species composition. This pattern is consistent with the results of related studies, indicating a broader ecological trend. The shifts observed here should raise concern among conservation ecologists, underscoring the importance of long-term monitoring to understand and mitigate the impacts of human activities on coastal ecosystems. Full article

The taxonomic composition, structure, and distribution patterns of the macrobenthos associated with Corallium rubrum were studied along the coast of Taranto (Ionian Sea), together with the main features of their red coral population. Underwater video transects were performed by professional divers at three sites in correspondence with coralligenous formations at depths from 50 to 65 m. The results revealed a patchy distribution of red coral, with colonies predominantly located in cavities on sub-vertical cliffs and large boulders. Biometric analysis indicated that young colonies predominated at all sites, while older colonies were lacking, likely because of illegal harvesting. The lower density values were recorded at S1, while S2 and S3 presented higher values. A total of 76 taxa were recorded. S1, the shallowest site, showed a prevalence of calcareous algae, while S2 and S3 showed a greater abundance of filter-feeding invertebrates (Porifera and Cnidaria) with the highest presence of Porifera at S3. The results emphasize the heterogeneity of the macrobenthos together with the high vulnerability of the red coral population, highlighting the necessity of site-specific conservation strategies to contribute to the conservation and management of benthic ecosystems in the northern Ionian Sea. Full article

Coral reefs off the coast of the Republic of Sudan are still considered to be among the most pristine reefs in the central Red Sea. The complex coastal fringing reefs, offshore banks, and shoals of Dungonab Bay in the north and Sanganeb atoll situated further to the south, about 23 km off the Sudanese mainland coast, were inscribed on the UNESCO World Heritage List in 2016. Due to their remote location and limited access, monitoring of the status of the reefs has been sporadic. Here, we present the results of a repeated large area photomosaic survey (5 m × 5 m plots) on the Sanganeb atoll, first established and surveyed in 1980, and revisited in 1991 and most recently in 2019. The 2019 survey recovered and reinstated the four original monitoring plots. Evaluation of photographic and video records from one photomosaic plot on the seaward slope of the atoll revealed general continuity of the overall community structure and composition over 39 years. Individual colonies of Echinopora gemmacea and Lobophyllia erythraea were recorded in the exact same positions as in the 1980 and 1991 plots. The genera Acropora and Pocillopora remain dominant, although in altered proportions. Shifts in composition were detected at the species level (e.g., increase in Pocillopora verrucosa, Stylophora pistillata, Acropora hemprichii, Dipsastraea pallida, and Echinopora gemmacea, decrease in Acropora cytherea and A. superba), in addition to changes in the extent of uncolonized substrate (e.g., increase from 43.9% in 1980 to 52.2% in 2019), and other scleractinian, hydrozoan, and soft coral living cover. While the temporal resolution only includes three sampling events over 39 years (1980, 1991, 2019), this study presents one of the longest time series of benthic community surveys available for the entire Red Sea. A semi-quantitative estimate of vertical reef growth in the studied test plot indicates a reduction in net accretion rates of more than 80%, from 2.27 to 2.72 cm/yr between 1980 and 1991 to 0.28–0.42 cm/yr between 1991 and 2019. We carefully conclude that the changes observed in the coral community in the plot in 2019 (Acropora–Pocillopora shift, increase in Montipora and calcareous algae) are representative of impacts at the community level, including rising sea surface temperatures and recent bleaching events. Full article

Red calcareous algae create bio-aggregations ecosystems constituted by carbonate calcium, with two main morphotypes: geniculate and non-geniculate structures (rhodoliths may form bio-encrustations on hard substrata or unattached nodules). This study presents a bibliographic review of the order Corallinales (specifically, rhodoliths), highlighting on morphology, ecology, diversity, related organisms, major anthropogenic influences on climate change and current conservation initiatives. These habitats are often widespread geographically and bathymetrically, occurring in the photic zone from the intertidal area to depths of 270 m. Due to its diverse morphology, this group offers a special biogenic environment that is favourable to epiphyte algae and a number of marine invertebrates. They also include holobiont microbiota made up of tiny eukaryotes, bacteria and viruses. The morphology of red calcareous algae and outside environmental conditions are thought to be the key forces regulating faunistic communities in algae reefs. The impacts of climate change, particularly those related to acidification, might substantially jeopardise the survival of the Corallinales. Despite the significance of these ecosystems, there are a number of anthropogenic stresses on them. Since there have been few attempts to conserve them, programs aimed at their conservation and management need to closely monitor their habitats, research the communities they are linked with and assess the effects they have on the environment. Full article

During the greenhouse conditions prevailing in the early–middle Eocene, larger benthic foraminifers (LBF) spread out on carbonate platforms worldwide while rhodolith beds were scarcely represented. This reduction in rhodolith beds coincided with a relative decrease in coralline algal diversity and with a drastic decline of coral reef abundance. Middle Eocene rhodoliths from two tropical (San Jacinto Fold Belt in northern Colombia and Bahoruco Peninsula in the Dominican Republic) and two mid-latitude (Salinas Menores Ravine and Sierra del Zacatín in Southern Spain) localities were studied. Rhodolith rudstones in the tropical areas accumulated on relatively deep (several tens of meters) platform environments and were also redeposited in deeper settings downslope. In Salinas Menores, rhodoliths are dispersed in planktic foraminifer-rich marls. Miliolids are common in the infilling of constructional voids in these rhodoliths, indicating that they originally grew in shallow-water inner-shelf settings and afterwards they were transported to deeper environments. In Sierra del Zacatín, rhodoliths are scarce and coralline algae mainly occur as crusts attached to and intergrowing with corals. Here, LBF dominated shallow-water carbonate platforms. In terms of taxonomic composition, coralline algae of the order Hapalidiales are the most abundant in the study areas, followed by Sporolithales. The order Corallinales is poorly represented except in Salinas Menores, where it is relatively abundant and diverse. The impact of high temperatures due to high levels of atmospheric CO₂ during the Eocene and widespread oligotrophic conditions, which favored formation of LBF-rich lithofacies, might account for the low abundance of rhodolith beds at mid and high latitudes. In contrast, the more productive equatorial regions would have favored the formation of rhodolith beds. Full article