Pablo Riul

Decrease in Lithothamnion sp. (Rhodophyta) primary production due to the deposition of a thin sediment layer

Coralline algae are important reef-builders which can form nodules, known as rhodoliths, occurring worldwide in beds sustaining a high biodiversity. Although considered a non-renewable resource, they are exploited as a source of calcium carbonate used mainly for agricultural purposes. In Brazil between 96,000 and 120,000 metric tonnes of rhodoliths are extracted per year. Besides the direct impact caused by removal on the coralline bed, the dredge process may also produce a plume of fine sediment, which can change the primary production of the remaining organisms. In this study, four treatments, with three replicates, were used to acquire Lithothamnion sp. net photosynthetic rates with and without a sediment layer using a Clark-type oxygen microelectrode and micromanipulator. The results demonstrated that, under controlled conditions, the addition of a thin sediment layer resulted in a 30% reduction of the irradiance, decreasing the Lithothamnion sp. net production in 70%. For this reason direct and indirect effects of mechanical exploitation of the rhodolith beds should be included in future studies that focus on environmental impacts of dredging activity, whether it is linked to the extraction of these algae.

Encrusting Sabellariidae (Annelida: Polychaeta) in rhodolith beds, with description of a new species of Sabellaria from the Brazilian coast

Rhodoliths or maerl are calcareous nodules of coralline red algae growing unattached to the substrata. They sustain a high biodiversity, being one of the most important marine benthic environments dominated by macrophytes. Sabellariidae are tube-dwelling filter feeding marine polychaetes that build their tubes by secreting cement from their thoracic glands. Some species are solitary, while others build tubes together, forming large aggregates. This study analyses Sabellariidae collected in rhodolith beds along the subtidal zone of the coast of Joao Pessoa and Cabedelo, Paraiba, north-eastern Brazil. A total of 100 individuals of six species were identified. Four are reported for the first time for the north-east coast of Brazil: Phragmatopoma caudata Morch (1863), Sabellaria bella Grube (1870), Sabellaria nanella Chamberlin (1919), and Sabellaria wilsoni Lana & Gruet ( 19 8 9 ). The first occurrence of Sabellaria pectinata Fauvel ( 1923 ) along the western Atlantic is provided as well as the description of a new species of the genus Sabellaria.

A Guide to Scientific Crowdfunding

Crowdfunding represents an attractive new option for funding research projects, especially for students and early-career scientists or in the absence of governmental aid in some countries. The number of successful science-related crowdfunding campaigns is growing, which demonstrates the public’s willingness to support and participate in scientific projects. Putting together a crowdfunding campaign is not trivial, however, so here is a guide to help you make yours a success.

The anti-predator role of within-nest emergence synchrony in sea turtle hatchlings

Group formation is a common behaviour among prey species. In egg-laying animals, despite the various factors that promote intra-clutch variation leading to asynchronous hatching and emergence from nests, synchronous hatching and emergence occurs in many taxa. This synchrony may be adaptive by reducing predation risk, but few data are available in any natural system, even for iconic examples of the anti-predator function of group formation. Here, we show for the first time that increased group size (number of hatchlings emerging together from a nest) reduces green turtle (Chelonia mydas) hatchling predation. This effect was only observed earlier in the night when predation pressure was greatest, indicated by the greatest predator abundance and a small proportion of predators preoccupied with consuming captured prey. Further analysis revealed that the effect of time of day was due to the number of hatchlings already killed in an evening; this, along with the apparent lack of other anti-predatory mechanisms for grouping, suggests that synchronous emergence from a nest appears to swamp predators, resulting in an attack abatement effect. Using a system with relatively pristine conditions for turtle hatchlings and their predators provides a more realistic environmental context within which intra-nest synchronous emergence has evolved.

Evaluation of impacts of climate change and local stressors on the biotechnological potential of marine macroalgae: a brief theoretical discussion of likely scenarios

Climate change can be associated with variations in the frequency and intensity of extreme temperatures and precipitation events on the local and regional scales. Along coastal areas, flooding associated with increased occupation has seriously impacted products and services generated by marine life, in particular the biotechnological potential that macroalgae hold. Therefore, this paper analyzes the available information on the taxonomy, ecology and physiology of macroalgae and discusses the impacts of climate change and local stress on the biotechnological potential of Brazilian macroalgae. Based on data compiled from a series of floristic and ecological works, we note the disappearance in some Brazilian regions of major groups of biotechnological interest. In some cases, the introduction of exotic species has been documented, as well as expansion of the distribution range of economically important species. We also verify an increase in the similarities between the Brazilian phycogeographic provinces, although they still remain different. It is possible that these changes have resulted from the warming of South Atlantic water, as observed for its surface in southeastern Brazilian, mainly during the winter. However, unplanned urbanization of coastal areas can also produce similar biodiversity losses, which requires efforts to generate long-term temporal data on the composition, community structure and physiology of macroalgae.

Global controls on carbon storage in mangrove soils

Global-scale variation in mangrove ecosystem properties has been explained using a conceptual framework linking geomorphological processes to distinct coastal environmental settings (CES) for nearly 50 years. However, these assumptions have not been empirically tested at the global scale. Here, we show that CES account for global variability in mangrove soil C:N:P stoichiometry and soil organic carbon (SOC) stocks. Using this ecogeomorphology framework, we developed a global model that captures variation in mangrove SOC stocks compatible with distinct CES. We show that mangrove SOC stocks have been underestimated by up to 50% (a difference of roughly 200 Mg ha−1) in carbonate settings and overestimated by up to 86% (around 400 Mg ha−1) in deltaic coastlines. Moreover, we provide information for 57 nations that currently lack SOC data, enabling these and other countries to develop or evaluate their blue carbon inventories.A global model that incorporates information about coastal environmental settings indicates that mangrove soil organic carbon stocks have been significantly underestimated in carbonate settings, and overestimated in deltaic coastlines.

Filling a Knowledge Gap on the Biodiversity of Rhodolith-Associated Echinodermata from Northeastern Brazil

Rhodolith beds formed by non-articulated calcareous algae have been recognized as important habitats for a range of organisms. The Brazilian coast is home to one of the largest beds of the Southwestern Atlantic, but the lack of faunal studies in these habitats represents one of our major gaps in the knowledge of Brazilian biodiversity. This study compares the composition, abundance and diversity of echinoderm species associated with rhodoliths in three different isobaths (10, 15 and 20 m) along the coast of the State of Paraíba, Northeastern Brazil. These rhodolith beds provided 2,855 specimens, representing 32 species from four Classes, of which Ophiuroidea was the most numerous. The echinoderm community was significantly different considering the abundance of individuals (F=452.86, p=0.001) and the number of species (F=45.14, p=0.006) among the three depths analyzed. Abundance and species numbers decrease with increasing depth. Rhodolith beds in the State of Paraíba are an important habitat for echinoderms, harboring a high diversity and abundance of associated species. Richness and diversity records exceed those found in other coastal areas around the world, indicating that these banks are of special relevance for the conservation of echinoderms in Brazil.