A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

Submitted to: IISCLBA – 2 ND SCIENTIFIC CONFERENCE OF LARGE SCALE BIOSPHEREATMOSPHERE EXPERIMENT IN AMAZÔNIA (LBA)MANAUS, AM, 07-10 JULY, 2002.THE ROLE OF MANGROVE ECOSYSTEM IN THE ATMOSPHERIC CARBONBUDGET - BRAGANCA, AMAZONIAN COASTAL REGION.Rafael FERREIRA da COSTA 1 ; R. B. SILVA 2 ; Paulo J. OLIVEIRA 3 ; Y. MALHI 3 ; P. MEIR 3 ;A. C. L. COSTA 2 ; J. M. N. COSTA 4 ; M. L. P. RUIVO 1 and V. ANDRADE 2 .1 MPEG/CCTE, Belém, PA, Brazil.Contact; e-mail: rfcosta@museu-goeldi.br or rfcostampeg@bol.com.br2 UFPA, Belém, PA, Brazil.3IERM/UEdin, Edinburgh, Scotland, UK.4 UFV, Viçosa, MG, Brazil.ABSTRACTThis study was conducted near of old small city of Braganca distant about 200 kmeast-northeast of Belém, Pará, Brazil (00°51´S, 46°38´W), at the estuary of the Caeteriver into the Large Scale Biosphere Atmosphere Experiment in Amazônia (LBA). Themangrove ecosystem are constituted by a wet forest kind in the coastal region, the majorpart of the tropical coastline, between latitudes of 30 o N and 30 o S, is edged bymangroves. The mean height of Braganca’s canopy is about 20m. The tree speciespredominant in the landscape of mangrove are Rhizophora mangle (red mangue),Avicennia germinans (siriuba) and Laguncularia racemosa (white mangue), some reacharound 25m high. The CO 2 fluxes measurements were made in an aluminium tower with30m high, where was installed an eddy covariance system (Edisol software, University ofEdinburgh), using a infrared gas analyser LI-6262 (Li-Cor, Nebraska, USA), the sonicanemometer was mounted in a metallic arm with 3m length at the top of tower, in theeasterly side minimising flow distortion for the prevailing wind direction. The CO 2 fluxeswere measured during a period in the beginning of rainy season (2-15 January 2001). Thetotal rain registered was 253.3mm with events in 13 of 14 days. The mean daily cycle ofCO 2 fluxes were +4.1µmolm -2 s -1 at 4 a.m. and –11.4µmol m -2 s -1 at 1 p.m. The dailycarbon budget reached –0.17 gCm -2 day -1 (day 6, with 19.1mm of rain), and –3.13 gCm -2 day -1 in January 7, with 1.9mm of rain. For all the period, the mean of carbon release tothe atmosphere was 1.8 gCm -2 day -1 (between 7p.m. until 7a.m) and the atmosphericcarbon sequestrated (between 8a.m and 6p.m.) was –3.2 gCm -2 day -1 . If extended for oneyear, the carbon budget will be –4.9 MgCha -1 year -1 . For that period, the mangroveecosystem functioned like a significant atmospheric carbon sink.Key words: Mangrove ecosystem, Carbon budget, Amazônia, Atmosphere.