New records of seaweeds and filamentous cyanobacteria from Trindade Island: an updated checklist to support conservation guidelines and monitoring of environmental changes in the southern Atlantic archipelagos

Abstract

Oceanic islands are natural laboratories for investigating species diversity and richness patterns. Changes in abiotic parameters may induce shifts in marine biota. Seaweeds are recognized as bioindicators, though those from remote tropical islands have been rarely studied. This study updates the diversity, richness and distribution of macroalgae from Trindade, a Brazilian volcanic island located 1140 km off the coast. Biotic data, obtained in a global database and in situ and compiled in a new records list, were associated with abiotic parameters. Conservation and ecological issues were discussed in the context of the observed greater richness, expansion of the distributional range and low endemism. A total of 141 species were identified, including 60 new records and 20 taxa of filamentous cyanobacteria. The greater richness, including potential cryptogenic species, may primarily be associated with past incomplete samplings, current new techniques and combined taxonomical methods, including molecular analysis for cryptic species. However, on the macroscale, this study provides information for the re-evaluation of aspects of endemism, connections and biogeographical distribution shifts of seaweed as­semblages, considering environmental changes. In addition, this updated checklist establishes a baseline for further compara­tive studies, reinforcing the hypothesis that biogeographical isolation can be disrupted by meteorological and oceanographic shifts, altering dispersal patterns and resulting in higher ecosystems connectivity.

Perdida em Meio à Vastidão do Oceano Atlântico: Síntese da Tendência de Publicações, Diversidade Biológica e Conservação na Ilha da Trindade

“…With a relatively high diversity in comparison with other Brazilian oceanic islands (e.g. Fernando de Noronha Archipelago, Rocas Atoll, Abrolhos and São Pedro e São Paulo Archipelago), Trindade Island has been suggested to be a hotspot for seaweeds in the Southwestern Atlantic, being a transition zone with low endemism as result of complex connectivity relationships (Sissini et al, 2017;Pellizzari et al, 2020). In comparison with other oceanic archipelagos, the Açores has a more diverse algal diversity, with more than 400 species (Freitas et al, 2019).…”

“…Island are still scarce, with the prevalence of oceanic taxa, such as fishes (Pinheiro and Gasparini, 2009;Pinheiro et al, 2016), birds (Luigi et al, 2009), and algae (Pellizzari et al, 2020). Also, there are two reported extinctions of native species on the island: the red-footed booby (Sula sula), locally extinct, and Peperomia beckeri E. F. Guim.…”

Compared antioxidant activity of six tropical macroalgal species from Trindade, a Brazilian oceanic island

“…Thus, oceanic islands are natural models to elucidate changing biochemical and oceanographic patterns (Pellizzari et al 2020a;Santos-Silva et al 2018). Trindade is a volcanic island located ca., 1,170 km off the Brazilian coast, and is the most isolated macroalgal community from Brazil, influenced by a complex ocean circulation pattern (Pellizzari et al 2020b).…”

“…Along Trindade beaches, the major stressing factors are herbivory (Tavares et al 2021), higher temperatures and UV radiation throughout the year (Pellizzari et al 2020b). One hypothesis posits that these environmental stressors may interact and engender synergistic or antagonistic effects on the physiological responses of seaweeds, thereby predisposing cell oxidation.…”

“…Phenolic compounds represent the most numerous group of secondary metabolites from plants and macroalgae, including bromophenol, phlorotannin, tocopherol, besides vitamin C and E (Hentati et al 2018). In seaweed physiology, phenolics compounds are involved in protection against UV radiation, resistance to pathogens, defense against epiphyte and anti-herbivory (Pellizzari et al 2020b). Carotenoids are essential to the conjugation and stability of some complex photosynthetic pigments-proteins and the photoprotection of these apparatus against oxidative damage (McDermid et al 2019).…”