Percorrer por autor "Soares, Marcelo O."
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- Rhodolith beds in Brazil—a natural heritage in need of conservationPublication . Schubert, Nadine; Magris, Rafael A.; Berchez, Flávio; Bernardino, Angelo F.; Ferreira, Carlos E. L.; Francini‐Filho, Ronaldo B.; Gaspar, Tainá L.; Pereira‐Filho, Guilherme H.; Rossi, Sergio; Silva, João; Sissini, Marina N.; Soares, Marcelo O.; Tâmega, Frederico T. S.; Tuya, Fernando; Horta, Paulo A.Aim: Brazil harbours the largest known extent of rhodolith beds (RBs) in the world, a habitat whose ecological and economic importance have been widely overlooked. This creates a dire situation that is likely to worsen with the rapidly expanding human activities, considering that less than 5% of Brazil's ocean area is fully protected. We assessed the importance of Brazilian RBs for supporting biodiversity, at a country-wide level, and identified multi-criteria hotspots that, in face of lack of protection and presence of anthropogenic threats, could safeguard conservation seascapes across Southwestern Atlantic waters. Location: Southwestern Atlantic Ocean. Methods: We performed a systematic review of studies on Brazilian RBs to retrieve information regarding their spatial distribution and associated biodiversity. Multi-criteria hotspots were identified based on the areas where high species diversity co-occurs with a high presence of endemic, threatened and commercially important species. Furthermore, we assessed how well RBs are covered by marine protected areas (MPAs), as well as their spatial overlap with multiple threats. Results: Existing records for Brazilian RBs indicate >1000 different species, mostly fish and algae, including significant numbers of endemic, threatened and commercially important species. Most of the RBs are either unprotected or only partially protected, including the majority of the biodiversity hotspots identified by our analysis. Among the main potential threats to RBs, bottom trawling ranks highest, while the expansion of seabed mining and oil and gas activities may sharply increase the risk of cumulative impacts on RBs in the near future. Main Conclusions: Our large-scale quantitative assessment confirms the significant role of RBs as biodiversity hotspots. This information could be leveraged to help meet the twin goals of RB conservation, through the establishment of highly-protected MPAs in hotspot areas, and their sustainable use through an ecosystem-based approach that accounts for vulnerabilities of RBs to multiple threats.
- Trophic ecology of Caribbean octocorals: autotrophic and heterotrophic seasonal trendsPublication . Rossi, Sergio; Schubert, Nadine; Brown, Darren; Gonzalez-Posada, Alba; Soares, Marcelo O.Studies over the past decades indicate that octocorals are becoming the dominant group in some areas of the Caribbean. Yet, basic knowledge about the trophic ecology of these organisms and their seasonal and species-specific variability is still scarce, though this might play a key role in determining their importance in benthic-pelagic coupling processes and, consequently, their role in carbon cycles. In the present study, two Caribbean gorgonian species (Plexaurella nutans and Pterogorgia anceps) were studied during an annual cycle, to assess seasonal variations in their reliance on heterotrophic versus autotrophic energy inputs. Zooplankton capture rates and bulk tissue stable isotopes were measured on a monthly basis to assess heterotrophic energy input, while autotrophic contribution was quantified monthly by Symbiodiniaceae cell densities and pigment contents, accompanied by seasonal measurements on Symbiodiniaceae (Breviolum sp.) photosynthetic performance and host respiratory demand. The results show that while autotrophy was the main energy source for both species, there was also a non-neglectable input through zooplankton that accounted for 0.2-0.8% and 0.7-3.4% of the energy demands in P. nutans and P. anceps, respectively. Our data further demonstrate that there are species-specific and seasonal differences in the contributions of these two nutrition modes, though there is no indication of shifts in the predominant mode during the year in either species. The energy inputs resulted in a positive energy balance throughout the year, with an energy surplus available for somatic growth, gonads, and/or energy reserves (e.g., lipids). However, the seasonal patterns differed between species, a feature that is most likely related to the different reproduction periods of the octocorals. Altogether, the information gathered here serves for a better understanding of the trophic ecology of mixotrophic octocorals and the seasonal variability of the nutritional modes that will define their potential impact in the carbon cycle and benthic-pelagic coupling processes of coral reefs.