Avaliação dos efeitos de temperatura e nutrientes sobre a ecofisiologia de Laurencia catarinensis (Ceramiales, Rhodophyta)

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Biologia de Fungos, Algas e Plantas, Florianópolis, 2015.Dentre as algas vermelhas os representantes com metabolismo secundário mais rico estão delimitados pelo gênero Laurencia (Ceramiales, Rhodomelaceae). Estes metabólitos apresentam importante papel ecológico e destacado potencial biotecnológico. Diversas espécies deste gênero possuem um metabolismo capaz de sintetizar substâncias de classes distintas, sendo os sesquiterpenos os mais abundantes e característicos do gênero. Estes papéis importantes nos ecossistemas marinhos são ameaçados, pelo aquecimento global e estressores locais uma vez que estas mudanças ambientais podem comprometer a aptidão fisiológica, empobrecendo o metabolismo secundário. Dessa forma, o presente trabalho teve com objetivo conhecer a fenologia reprodutiva de Laurencia catarinensis nos períodos de verão e inverno para então avaliar os impactos causados pelo aquecimento global e poluição antrópica sobre aspectos bioquímicos e fisiológicos da alga.Primeiramente, este trabalho avaliou a variação sazonal das concentrações dos pigmentos fotossintetizantes, Amido, compostos fenólicos totais, atividade antioxidante e no geral, pode-se observar que ocorreu aumento do conteúdo de clorofila a, Ficobiliproteínas e amido no perído de inverno e aumento das concentrações para os compostos fenólicos e carotenoides no período de verão, para praticamente todos os estádios reprodutivos.Dentro deste contexto, foi possível inferir, através do experimento realizado com a macroalga, que poderá ocorrer o aumento da sensibilidade de L. catarinensis a fatores como aquecimento global e poluição antrópica. Para a Taxa de crescimento relativo nas menores temperaturas com adição de nutrientes, o crescimento da macroalga foi maior variando entre (0,58 mg/gMF a 3,37 mg/gMF). Níveis altos de poluentes e o aumento da temperatura demonstraram toxicidade a macroalga podendo causar alterações bioquímicas e fisiológicas, diminuindo a produção de clorofila a nos tratamentos com concentrações altas de nutrientes (CAN) e temperatura de 28°C, em contrapartida o aumento das concentrações dos pigmentos acessóriosFicocianina e Ficoeritrina para aumento da captação de luz ao aparato fotossintético. Dessa forma, a análise do perfil dos carotenoides determinados por cromatografia liquida de alta eficiência (CLAE) identificou a Luteína, Zeaxantina e a- caroteno. A Luteína foi o composto majoritário em todos os tratamentos. Com relação ao perfil de compostos fenolicos (determinados por CLAE) foram detectados os seguintes compostos: epicatequina, galocatequina, epigalocatequina, acido cafeico, 4,5 dicafeoilquinico, acido Cumárico e dois compostos ainda não identificados (Composto X-Rt 4,3 min e Composto Y-Rt 9,2 min), sendo o composto majoritário a Epicatequina. O conteúdo de carotenoides e compostos fenólicos pode ser associado ao aumento de temperatura e fotoproteção e ao estresse causado pelo incremento de nutrientes, sendo que o mesmo pode ser verificado pelo teste de atividade antioxidante que foi observado em maior porcentagem no tratamento a 28°C. Com relação aos conteúdos de açucares totais e amido, ocorreu diminuição do conteúdo destes compostos produzidos pelas algas na temperatura de 28°C e no tratamento CAN.Para os dados da fluorescencia da clorofila a analisados através do PAM, verificou-se decréscimo da irradiância de saturação (Ik) da alga L.catarinensis na temperatura de 28°C, o mesmo também foi observado nos parâmetros ?F/F´m, ETR e a ETR. Para os dados de Fv/Fm tanto os tratamentos CBN quanto CAN decresceram seus valores em temperaturas de 28°C.Abstract : Among the red algae, representatives with richest secondary metabolism are delimited by genus Laurencia (Ceramiales, Rhodomelaceae). These metabolites have important ecological role and highlighted biotechnological potential. Several species of this genus have a metabolism able to synthesize different classes of substances, sesquiterpenes being the most abundant and characteristic of the genus. These important roles in marine ecosystems are threatened by global warming and local stressors because these environmental changes can impair the physiological fitness, impoverishing the secondary metabolism. Thus, this study was carried out to know the reproductive phenology of L. catarinensis in the summer and winter seasons and then evaluate the impacts of global warming and anthropogenic pollution on biochemical and physiological aspects of seaweed.First, this study evaluated the seasonal variation of concentrations of photosynthetic pigments, Total sugars, starch, total phenolics, antioxidant activity and can be seen that there was an increase of chlorophyll content, Phycobiliproteins, total sugars and starch in the winter period prescribed and increasing concentrations for the phenolic compounds and carotenoids in the summer period, for practically all reproductive stages. Inside this context, it was possible to conclude, with this study, which could take the increased sensitivity of L. catarinensis to factors such as global warming and anthropogenic pollution. For the growth rate on the lower temperatures with the addition of nutrients, the growth of macroalgae was higher ranging from (0.58 mg / gDW to 3.37 mg / gDW). High levels of pollutants and increasing temperature to demonstrate toxicity seaweed causing biochemical and physiological changes, reducing the production of chlorophyll in treatments with high concentrations of nutrients (HNC) and of 28 °C, however increasing concentrations of pigments acessories Phycoerythrin and Phycocyanin and for increased light reception the photosynthetic apparatus. Thus, the profile analysis of carotenoids determined by high performance liquid chromatography(HPLC) identified Lutein, Zeaxanthin and a-carotene. Lutein was the major compound in all treatments. Regarding the profile of phenolic compounds (determined by HPLC) The following compounds were detected: epicatechin, gallocatechin, epigallocatechin, caffeic acid, 4,5 dicaffeoylquinic, coumaric acid and two as yet unidentified compounds (Compound X-Rt 4.3 min, compound Y-Rt 9.2 min), being the major compound epicatechin. The content of phenolic compounds and carotenoids was associated with increases in temperature and photoprotection and stress caused by the increase of nutrients, where it can be verified by the test that the antioxidant activity was observed in a greater percentage in the treatment at 28°C. Relative to those of total sugars and starch content, a decrease in the temperature of 28°C and HNC, these compounds produced by algae. For the chlorophyll a fluorescence , there was a decrease in saturation irradiance (Ik) of the algae L.catarinensis at 28°C, it was also observed in parameters ?F/ F'm parameters ETR and a ETR. For data Fv / Fm both treatments LNC and HNC decreased their values in temperatures of 28°C

Global impacts of projected climate changes on the extent and aboveground biomass of mangrove forests

Aim: Over the past 50 years, anthropogenic activities have led to the disappearance of approximately one-third of the world's mangrove forests and their associated ecosystem services. The synergetic combined effect of projected climate change is likely to further impact mangroves in the years to come, whether by range expansions associated with warming at higher latitudes or large-scale diebacks linked to severe droughts. We provide an estimate of future changes in the extent and aboveground biomass (AGB) of mangrove forests at global scales by considering contrasting Representative Concentration Pathway scenarios (decade 2090-2100 under RCP 2.6 in line with the Paris Agreement expectations, and RCP 8.5 of higher emissions). Location: Global. Methods: Boosted regression trees fitted occurrence and AGB of mangroves against high-resolution biologically meaningful data on air temperature, precipitation, wave energy, slope and distance to river Deltas. Results: On the global scale, models produced for present-day conditions retrieved high accuracy scores and estimated a total area of 12,780,356 ha and overall biomass of 2.29 Pg, in line with previous estimates. Model projections showed poleward shifts along temperate regions, which translated into comparable gains in total area, regardless of the RCP scenario (area change RCP 2.6: 17.29%; RCP 8.5: 15.77%). However, biomass changes were dependent on the emission scenario considered, remaining stable or even increasing under RCP 2.6, or undergoing severe losses across tropical regions under RCP 8.5 (overall biomass change RCP 2.6: 12.97%; RCP 8.5: -11.51%). Such losses were particularly aggravated in countries located in the Tropical Atlantic and Eastern Pacific, and the Western and Eastern Indo-Pacific regions (regions with losses above similar to 20% in overall biomass). Conclusions: Our global estimates highlight the potential effect of future climate changes on mangrove forests and how broad compliance with the Paris Agreement may counteract severe trajectories of loss. The projections made, also provided at the country level, serve as new baselines to evaluate changes in mangrove carbon sequestration and ecosystem services, strongly supporting policy-making and management directives, as well as to guide restoration actions considering potential future changes in niche availability.info:eu-repo/semantics/publishedVersio

Phenotypic plasticity in sargassum forests may not counteract projected biomass losses along a broad latitudinal gradient

Phenotypic plasticity and local adaptation can adjust individual responses to environmental changes across species' ranges. Studies addressing the implications of such traits have been underrepresented in the marine environment. Sargassum cymosum represents an ideal model to test phenotypic plasticity, as populations along the southwestern Atlantic Ocean display a sharp decrease in abundance toward distributional range limits. We (1) characterized the macroecological environment of S. cymosum across a latitudinal gradient, (2) evaluated potential differences in ecophysiological adjustments (biomass, photosynthetic pigments, phenolic compounds, total soluble sugars and proteins, and carbon-nitrogen-CN-content), and (3) tested for differences in thermal tolerance based on time series analyses produced from the present to contrasting representative concentration pathways scenarios (RCP) of future climate changes. Our results showed distinct macroecological environments, corresponding to tropical and warm temperate conditions, driving biomass and ecophysiological adjustments of S. cymosum. Populations from the two environments displayed contrasting thermal tolerances, with tropical individuals better coping with thermal stress when compared to more temperate ones (lethal temperatures of 33 degrees C vs. 30 degrees C); yet both populations lose biomass in response to increasing thermal stress while increasing secondary metabolites (for example, carotenoids and phenolic compounds) and decrease chlorophyll's content, Fv/Fm, total soluble sugars concentration and CN ratio, owing to oxidative stress. Despite evidence for phenotypic plasticity, significant future losses might occur in both tropical and warm temperate populations, particularly under the no mitigation RCP scenario, also known as the business as usual (that is, 8.5). In this context, broad compliance with the Paris Agreement might counteract projected impacts of climate change, safeguarding Sargassum forests in the years to come.This study was supported by grants from Boticario Foundation, FAPESC-Foundation Support Research and Innovation in the State of Santa Catarina, Capes Higher Education Personnel Improvement Coordination, CNPq-National Council for Scientific and Technological Development, Petrobras Ambiental, REBENTOS-Habitat monitoring network coastal Benthic and ProspecMar-Islands Sustainable Prospecting in Ocean Islands: Biodiversity, Chemistry, Ecology and Biotechnology, Rede Coral Vivo, REDEALGAS, a Pew Marine Fellowship, the Foundation for Science and Technology (FCT) of Portugal via SFRH/BSAB/150485/2019, SFRH/BD/144878/2019, UID/Multi/04326/2019, PTDC/BIA-CBI/6515/2020 and the transitional norm DL57/2016/CP1361/CT0035. LPG received a doctorate scholarship (88882.438723/2019-01) from Capes. CFDG thanks CNPq grants PQ-309658/2016-0and306304/2019-8. PAH thanks CAPES-Senior Visitor, CAPESPrInt 310793/2018-01, CNPq-PVE 407365/2013-3, CNPq-Universal 426215/2016-8 and CNPq-PQ308537/2019-0. GK received a master's scholarship from CAPES.info:eu-repo/semantics/submittedVersio

Corrigendum to “Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation” [Sci. Total Environ., 729 (2020) Start page – End page/ 138745]

info:eu-repo/semantics/publishedVersio

Impactos das mudanças climáticas nas florestas marinhas e costeiras: cenário atual e perspectivas futuras

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Ecologia, Florianópolis, 2021.Iniciativas de mitigação de mudanças climáticas atraíram um grande interesse no papel dos ?sumidouros naturais de carbono?, particularmente nos ecossistemas marinhos costeiros. A biomassa acima do solo (AGB) representa uma parte substancial do reservatório de carbono orgânico das florestas marinhas que podem ser afetadas pelas mudanças climáticas. A importância do estudo de perdas AGB tem se tornado cada vez mais urgente, porque é a partir dela que o CO2 atmosférico é incorporado no organismo e assim transforma-se em biomassa. Desta forma, este trabalho teve como objetivo investigar os fatores ambientais responsáveis pela variabilidade espacial da biomassa e distribuição de florestas marinhas e costeiras como aquelas estruturadas por Sargassum e Manguezais, sob cenários futuros de mudanças climáticas. No primeiro capítulo, nós utilizamos ferramentas estatísticas de modelagem de ocorrência e biomassa ?Boosted regression trees? (BRT), para mostrar o importante destaque da macroalga Sargassum como um potencial recurso para mitigação de CO2. Sargassum AGB totalizou 13,1 Pg C em escala global, o que é uma quantidade significativa de carbono e comparável a outros ecossistemas marinhos, como florestas de mangue, marismas e gramas marinhas. No capítulo 2, nós avaliamos as diferenças no ajuste ecofisiológico de Sargassum ao longo da costa brasileira e testamos se estes ajustes eram suficientes para a manutenção do crescimento, sob cenários futuros de aquecimento global. Nós verificamos que o Sargassum apresenta compostos químicos ao longo da costa brasileira impulsionados por fatores ambientais macroecológicos que também determinam províncias e ecorregiões biogeográficas. Os fatores abióticos, principalmente a temperatura nos trópicos, levam a grandes estoques de biomassa e carbono. As duas populações de Sargassum cymosum podem perder biomassa em conseqüência da diminuição da taxa de crescimento relativo sob estresse térmico, particularmente se o clima do planeta seguir o pior cenário RCP 6.0 e 8.5. Populações de borda como as que estão presentes em Santa Catarina apresentaram maior suceptibilidade na temperatura de 30°C, pois as taxas de crescimento passam a apresentar valores negativos, aproximadamente -1% d-1. Por fim, no terceiro capítulo, nós analisamos as perdas de área e AGB nas florestas de mangues sob mudanças climáticas previstas nos cenários (RCP 2.6 e 8.5), levando em consideração temperatura e precipitação, através da modelagem estatistica BRT. As perdas potenciais de biomassa em florestas de mangue devido às mudanças climáticas variam de 5 a 14% na área e de 26 a 42% na biomassa em escala global. Isso corresponde a perdas absolutas de 8.345 a 24.212 km2 e de 0,56 a 0,90 Pg de AGB. Nossos resultados reforçam a importância de estudos com enfoque na perda de área/biomassa e consequentemente dos serviços ecossistêmicos por ambientes marinhos. Este estudo mostra como a variação dos recursos ambientais sob mudanças climáticas podem aumentar a vulnerabilidade das espécies, principalmente das macroalgas formadoras de dossel como o Sargassum e florestas de mangues.Abstract: Climate change mitigation initiatives have attracted interest in the role of natural carbon sinks, particularly in coastal systems. The atmospheric CO2 is incorporated into the organism and convert in biomass. Above-ground biomass (AGB) represents a substantial part of the organic carbon reservoir in marine forests that can be affected by climate changes. Here, we address the environmental factors responsible for the spatial variability in distribution and AGB of two important components of marine ecosystems, such as Sargassum and mangrove forests under climate changes. The first chapter addresses the potential role of Sargassum in climate change mitigation. We modelled global distributions and quantified carbon stocks as above-ground biomass (AGB) with machine learning algorithms ?Boosted regression trees? and climate data. Sargassum AGB totalled 13.1 Pg C on a global scale, which is a significant amount of carbon and comparable to other marine ecosystems, such as mangrove forests, salt marshes and seagrass. In Chapter 2, we assessed the differences in Sargassum's ecophysiological adjustment along the Brazilian coast, and we tested for differences in the thermal sensibility to warming between edge populations collected in tropical and warm temperate regions. Sargassum presents chemical compounds along the Brazilian coast driven by macroecological environmental factors that also determine provinces and biogeographic ecoregions. Abiotic factors, especially temperature in the tropics, leading to large stocks of biomass and carbon. However, the two populations of Sargassum cymosum could lose biomass because of the decrease in the relative growth rate under thermal stress, mainly if the planet's climate follows the RCP 8.5 scenario. Edge populations in the warm temperate region showed greater susceptibility at a temperature of 30°C, and growth rates presented negative values around -1% d-1. In the last chapter, we report the potential loss of mangrove forests under contrasting scenarios of future climate change (RCP 2.6 and 8.5) by modelling global distributional and biomass shifts. Potential biomass losses in mangrove forests varied from 5 to 14% in the area and from 26 to 42% in biomass on a global scale. This corresponds to total losses of 8,345 to 24,212 km2 and 0.56 to 0.90 Pg of AGB. Our results reinforce the importance of studies focusing on the loss of area/biomass and, consequently, on ecosystem services in marine environments. This study shows how the variation of environmental resources under climate change can increase the vulnerability of species, especially canopy-forming macroalgae such as Sargassum and mangrove forests

Range map data of marine ecosystem structuring species under global climate change

Data on contemporary and future geographical distributions of marine species are crucial for guiding conservation and management policies in face of climate change. However, available distributional patterns have overlooked key ecosystem structuring species, despite their numerous ecological and socioeconomic services. Future range estimates are mostly available for few species at regional scales, and often rely on the outdated Representative Concentration Pathway scenarios of climate change, hindering global biodiversity estimates within the framework of current international climate policies.Here, we provide range maps for 980 marine structuring species of seagrasses, kelps, fucoids, and cold-water corals under present-day conditions (from 2010 to 2020) and future scenarios (from 2090 to 2100) spanning from low carbon emission scenarios aligned with the goals of the Paris Agreement (Shared Socioeconomic Pathway 1-1.9), to higher emissions under reduced mitigation strategies (SSP3-7.0 and SSP5-8.5). These models were developed using state-of-the-art and advanced machine learning algorithms linking the most comprehensive and quality-controlled datasets of occurrence records with high-resolution, biologically relevant predictor variables. By integrating the best aspects of species distribution modelling over key ecosystem structuring species, our datasets hold the potential to enhance the ability to inform strategic and effective conservation policy, ultimately supporting the resilience of ocean ecosystems

Range map data of marine ecosystem structuring species

Range map data, encompassing 980 marine ecosystems structuring species of seagrasses, kelp forests, fucoids, and cold-water corals, were generated using machine learning algorithms linked with datasets of occurrence records and biologically relevant predictor variables. These data comprise predictive habitat suitability maps for each species under present-day conditions and future climate change scenarios at a global scale, along with uncertainty maps depicting the standard deviation of predictive responses. The performance of the models was assessed under a cross-validation framework, and the relative contribution, as well as physiological tolerance limits (tipping points) for each predictor variable, were determined.</p