Living with an enemy: Invasive sun-coral (Tubastraea spp.) competing against sponges Desmapsamma anchorata in southeastern Brazil.

The azooxanthellate corals Tubastraea coccinea and T. tagusensis invaded the Brazilian coast in the 1980s and is still in expansion, favored by lower predation and competition pressure in their new habitats. Interestingly, the native sponge Desmapsamma anchorata has been observed overgrowing these corals. Considering that competitive displacement is expected to play a major role in the successful outcome of an invasion, the present study tested the physical and chemical mechanisms possibly involved in the competition between D. anchorata and the Tubastraea corals through field and aquaria experiments as well as the Raman spectroscopy technique for chemical analysis. Our results showed that the sponge grew in all directions including over Tubastraea colonies and regardless of its presence. There was no evidence of a specific chemical response among sponges or corals. However, we observed the extrusion of mesenteric filaments and tentacles of corals and the projection of sponge tissue during interspecific interaction, which suggests that physical imposition plays a key role for space competition at micro scales. Given the interspersed nature of benthic species distributions and the fast expansion of Tubastraea, it is unlikely that D. anchorata or any other sponges could serve a biological control against these invasive corals at larger scales, but our results showed that at a microscale they can withstand the corals presence and even outgrow them locally.

Abnormal average increase in sea surface temperature may promote the first documented mortality event of a marine sponge in the Southeastern Brazil / Aumento na temperatura média do mar pode ter causado o primeiro evento registrado de mortalidade de esponjas marinhas no Sudeste do Brasil

Abstract Frequent heat waves and mass mortality events on marine biota are positively correlated to ocean warming. Although literature has indicated some species of marine sponges, and some oceanic regions, like the Brazilian Exclusive Economic Zone, may be less affected or seem to be more resilient under future scenarios of climate changes, few studies have focused on the species responses on the climate change issue along Brazilian coast. This paradigm was undone throughout 2019 after an exceptional average increase of 2 °C in the sea surface temperature (SST) and on precipitation values since 2015 at Ilha Grande Bay (IGB, SE Brazil). The combination of SST and precipitation average increase possibly favored an environmental context for the unprecedented strong population decline and mass mortality rate of the marine sponge species Desmapsamma anchorata in the austral spring. The species used to be one of the most frequent benthic species at IGB however it was only recorded in 41.7% sites (n = 12). From 162 individuals recorded at Abraãozinho along 180 m rocky shore, 83 individuals (51.2%) were healthy, 74 (45.7%) were intensively covered by cyanobacteria and locally bleached, and five (3.1%) were completely bleached or died. Desmapsamma anchorata population deterioration in a biogeographic transition zone (Rio de Janeiro state) may reflect a shift in the marine community of IGB, opening space for opportunistic species establishment and coverage increase, since IGB has a high species turnover. The three-dimensionality, the shelter for several species, the high competitive ability and the potential to indicate polluted or not polluted areas make D. anchorata a key species for IGB monitoring in a climate change scenario.

Resumo Ondas de calor e eventos de mortalidade em massa da biota marinha são cada vez mais frequentes e estão positivamente correlacionados ao aquecimento do oceano. Embora a literatura tenha indicado que algumas espécies de esponjas marinhas e algumas regiões oceânicas, como a Zona Econômica Exclusiva do Brasil, podem ser menos afetadas ou serem mais resilientes em cenários futuros de mudanças climáticas, poucos estudos focaram na resposta das espécies à problemática das mudanças climáticas na costa brasileira. Esse paradigma foi desfeito em 2019 após um excepcional aumento médio de 2 °C na temperatura da superfície do mar e nos valores de precipitação, desde 2015 na Baía da Ilha Grande (BIG, SE Brasil). Essa combinação de fatores possivelmente favoreceu um contexto ambiental sem precedentes, levando ao forte declínio populacional e alta taxa de mortalidade da esponja marinha Desmapsamma anchorata na primavera austral. A espécie costuma ser uma das espécies bentônicas mais frequentes na BIG, mas só foi observada em 41,7% dos sítios (n = 12). De 162 indivíduos registrados em Abraãozinho ao longo de 180 m de costão rochoso, 83 indivíduos (51,2%) estavam saudáveis, 74 (45,7%) estavam cobertos por cianobactéria e localmente branqueados e cinco (3,1%) estavam completamente branqueados ou mortos. A deterioração da população de D. anchorata na zona de transição biogeográfica (estado do Rio de Janeiro) pode refletir em uma alteração na comunidade marinha da BIG, abrindo espaço para o estabelecimento de espécies oportunistas, uma vez que a BIG possui alto turnover. A tridimensionalidade, o abrigo a diversas espécies, a alta capacidade competitiva e o potencial de indicar áreas poluídas ou não tornam D. anchorata uma espécie chave no monitoramento da BIG em um cenário de mudanças climáticas.

Anti-inflammatory potential of invasive sun corals (Scleractinia: Tubastraea spp.) from Brazil: alternative use for management?

OBJECTIVES: The objective was to analyse the anti-inflammatory potential of the invasive coral species Tubastraea coccinea and Tubastraea tagusensis. METHODS: Methanolic extracts, fractions and synthesized compounds were evaluated for their anti-inflammatory ability, and their composition was elucidated through chemical analysis. KEY FINDINGS: The genus Tubastraea (Order Scleractinia, Family Dendrophylliidae) (known as sun corals) presents compounds with pharmacological value. The introduction of these azooxanthellate hard corals into Brazil, initially in Rio de Janeiro state, occurred through their fouling of oil and gas platforms from the Campos oil Basin. The two invasive species have successfully expanded along the Brazilian coast and threaten endemic species and biodiversity. The HPLC-MS and GC-MS data suggest the presence of aplysinopsin analogues (alkaloids). Anti-inflammatory activity was observed in all samples tested in in-vivo assays, especially in T. coccinea. The ethyl acetate fraction from this sample was more effective in in-vitro assays for anti-inflammatory activity. Depending on the concentration, this fraction showed cytotoxic responses. CONCLUSIONS: These species have potential pharmacological use, and considering their invasive nature, this study presents a potential alternative use, which may enhance the management of this biological invasion.

Mutagenic, genotoxic and cytotoxic studies of invasive corals Tubastraea coccinea and Tubastraea tagusensis.

The high diversity of species in the marine environment gives rise to compounds with unique structural patterns not found as natural products in other systems and with great potential for pharmacological, cosmetic and nutritional use. The genus Tubastraea (Class Anthozoa, Order Scleractinia, Family Dendrophylliidae) is characterized as a hard coral without the presence of zooxanthellae. In species of this genus alkaloids derived from the compound aplysinopsin with pharmacological activity are known. In Brazil T. coccinea and T. tagusensis are characterized as non-indigenous and invasive and are currently found along the Brazilian coast, from Santa Catarina to Bahia states. This study aims to analyze the mutagenic, cytotoxic and genotoxic potential of methanolic and ethanolic extracts from T. coccinea and T. tagusensis collected in Ilha Grande Bay, Rio de Janeiro state, Brazil. Bacterial reverse mutation assay on the standard strains TA97, TA98, TA100, TA102 and TA104, in vitro micronucleus formation test and colorimetric assays for cytotoxic signals on the cell lines HepG2 and RAW264.7 were used. We also synthesized an oxoaplysinopsin derivate alkaloid (APL01) for comparative purposes. No mutagenic (250; 312.5; 375; 437.5 and 500 µg/plate) or genotoxic (0.05; 0.5; 5.0; 50 and 500 µg/mL) effects were observed in any sample tested for all measured concentrations. Cytotoxic responses were observed for eukaryotic cells in all tested samples at 500 and 5000 µg/mL concentrations. Cytotoxicity found in the WST-1 assay was independent of the metabolism of substances present in samples compositions. The cytotoxicity observed in the LDH release assay depended on metabolism.

Fatty acids as chemotaxonomic markers of marine macrophytes from Rio de Janeiro state, Brazil.

The distribution of fatty acids in 13 species of macroalgae (Chlorophyta, Ochrophyta and Rhodophyta) and 1 seagrass (Spartina sp), collected on the Rio de Janeiro state coast was determined. The results were evaluated in search of correlations between the taxonomic and phylogenetic position of these macrophytes. Statistical analyses showed the effectiveness as taxonomic and phylogenetic markers of the distribution of the methyl fatty acid esters in these macrophytes.