Avaliações diárias e sazonais das concentrações de CO2 em um ecossistema de manguezal: dimensões micrometeorológicas e econômicas

• Autor(a) principal: Fonseca, Sérgio de Mattos
• Data de Publicação: 2010
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1498
• topic: Manguezal; Créditos de carbono; Micrometeorologia; Mangrove; Carbon credits; Micrometeorologic; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::METEOROLOGIA::MICROMETEOROLOGIA

This study stands out a pioneering project assessing the concentrations and fluxes of carbon in mangrove forests canopy of Para, Brazil. Developed in the context of LBA - Experiment of Large Scale Biosphere-Atmosphere Experiment in Amazonia has operated on an experimental site in the city of Bragança, who hosted the project CARBO-PARA / LBA. In a forest whose canopy reaches heights up to 25 meters were installed meteorological equipment and a system of eddy covariance for continuous measurements of CO2 fluxes. Data from the mangrove ecosystem experimental site of Bragança (PA) suggest the need for an extension of studies on trade flows of mass and energy, and correlation with the economic value of that ecosystem. The technique, known as method of eddy covariance allows to determine if an ecosystem, especially mangroves, is a source or a sink of atmospheric CO2. The following results can be pointed out in this work: a) The lower CO2 concentrations above the mangrove vegetation during the diurnal period occurred around noon, with a mean variation from 352 ppm in March to 392 ppm in October. b) The highest CO2 concentrations over the mangrove on a daily basis, occurred at night, as expected, with a mean variation of 380 ppm (November) to 460 ppm (May). c) The best correlated variables with CO2 concentration, in decreasing order of importance, were: air temperature, global solar radiation, atmospheric stability parameter, friction velocity and wind speed. d) The influence of the tidal on the hourly CO2 concentration was not significant statistically, but, it should be pointed out the effect of the level of water at the peak of the tidals on the magnitudes of CO2 concentration. e) The mean assimilation rates of CO2 during the diurnal period ranged from –7.37 μmol.CO2.m-2.s-1 (June) to –10.75 μmol.CO2.m- 2.s-1 in September, with an overall average during the experimental work of –9.25 μmol.CO2.m-2.s-1. f) The mean ecosystem respiration rates during the nocturnal periods ranged from 3.47 μmol.CO2.m-2.s-1 (March) to 6.31 μmol.CO2.m-2.s-1 (June), with an overall average of 4.47 μmol.CO2.m-2.s-1, during the experimental work. In the context of the Kyoto Protocol project activities for the establishment or reforestation of mangrove ecosystems appear to be quite attractive and economically viable for implementation, either for projects in areas as demonstrated by the thesis, or for more ambitious projects, involving larger areas in activities of afforestation or reforestation. In relation to the Compensation Fund for avoided emissions, such as the newly proposed REDD, if they are included in national accounts of non-anthropogenic removals, as the natural evolution of carbon stocks in forests, is implicit in the thesis proposal: the removals by sinks (mangrove ecosystems) must be paid annually by the balance of NEE calculated and expressed by the average flux of CO2 captured annually per unit area of the ecosystem preserved. The results corroborate the veracity of the hypothesis of this study, which indicates the viability of the afforestation or reforestation of mangroves as project activities for inclusion in the form of CDM / LULUCF or Compensation Funds (REDD et alii), using the methodology described in this study to calculate avoided emissions, reductions and certifications. The experiment conducted in Bragança (PA) points to a net gain of 16.6 TC.ha-1.ano-1 and the possibility of generating up to 60 certificates for reduced emissions per hectare of mangrove forest preserved, restored or planted per year.