Shozo Shiraiwa

Seasonal variation in the leaf gas exchange of tropical forest trees in the rain forest-savanna transition of the southern Amazon Basin

The photosynthetic light response of Amazonian semi-deciduous forest trees of the rain forest-savanna transition near Sinop Mato Grosso, Brazil was measured between July 2000 and September 2003 to test the hypothesis that the photosynthetic capacity of trees acclimated to different growth light environments will decline during the dry season. Maximum photosynthesis (A max ) and stomatal conductance (g max ) were significantly higher during the wet season; however, the physiological response to drought was not a clear function of growth light environment. For some species, such as Psychotria sp. growing in the mid-canopy, internal leaf CO 2 concentration (C i ) was > 30% lower during the dry season suggesting that declines in A max were caused in part by stomatal limitations to CO 2 diffusion. For other species, such as Brosimum lactescens growing at the top of the canopy. Tovornita schomburgkii growing in the mid-canopy, and Dinizia excelsa growing in the understorey, dry season C i declined by < 20% suggesting that factors independent of CO 2 diffusion were more important in limiting A max . Dry-season declines in g max appeared to be important for maintaining a more consistent leaf water potential for some species (T. schomburgkii and D. excelsa) but not others (Psychotria sp.). These results indicate that while seasonal drought exerts an important limitation on the physiological capacity of semi-deciduous Amazonian forest trees, the mechanism of this limitation may differ between species.

Estudos geofísicos integrados no lixão de Cuiabá, MT, Brasil: resultados preliminares

One of the major concerns in geoenvironmental projects is the soil and water contamination caused by the waste disposal. The geophysical methods applied are a good way to get some information required in a site characterization program. This work shows some results obtained through resistivity, EM inductive and GPR surveys in the search of informations about the impact caused by a waste disposal area in Cuiaba, State of Mato Grosso, Brazil.

Aplicação de métodos geofísicos para identificar áreas contaminadas por resíduos de um curtume

The main problem on environmental investigations is the determination of contaminated extension area. This work exhibit some results obtained with the geophysical methods applied to locate potentially contaminated areas with tanning residues. The area is located near to the city of Varzea Grande, Mato Grosso State. It was now interdicted and disabled for the residues deposition. The data were acquired from electrical profiles, with inline dipole-dipole array and 4 m spacing electrodes, allowing 5 investigation depths. The data of apparent electric conductivity were acquired in 2 dipole modes (horizontal and vertical coplanar) with intercoil spacing of 10 meters. The 200 MHz unshielded antennas were used to collect GPR data. The station interval to each 0.25 meters and 128 stacks. The areas were classified in Contaminated Area - AC - (sa > 40 mS/m, r 50 ohm.m and low attenuation of GPR). The integrated results allow the contamination maps elaboration, indicating a potentially contaminated area with a preferential NW-SE flux. The geophysics and geological information showed an efficient preliminary analysis in the identification of contaminated areas.

GPR para a verificação do nível d'água subterrânea em transição floresta amazônica e cerrado

A Ground Penetratin Radar (GPR) water level monitoring study of a mature transitional tropical forest is presented. Three water tables monitoring wells were installed during 2001/2002 at three different sites: under permanent forest, under managed forest and pasture. The GPR profiles show that the water table appears as a strong horizontal reflector in March and August, 2002,and as a weak, discontinuous reflector during measurements in May and October 2001. Due to several laterite lenses in the soil, the water table can easily be mistaken in place of such lenses. Soil moisture had an influence on these reflection signals, changing the dielectric constant of soil. The depth of the water table varied 1.8 m under permanent forest, 0.9 m under management forest and 3.7 m under pasture.

Aplicação do método eletromagnético indutivo na investigação da pluma de contaminação da água subterrânea por resíduos de cromo de curtume

Este trabalho apresenta os resultados obtidos com a aplicacao do metodo eletromagnetico indutivo, para descrever a estrutura aquifera e eventual contaminacao relacionada a residuos de couro no distrito de Capao Grande, em Varzea Grande, Estado de Mato Grosso. Esta area fora utilizada por mais de 10 anos como local de descarte de lodo de curtume em valas previamente escavadas no solo, estando atualmente interditada pela SEMA-MT - Secretaria de Estado do Meio Ambiente de Mato Grosso. Os resultados obtidos com a aplicacao do metodo eletromagnetico indutivo mostraram que tanto no nivel de 7,5 m como de 15,0 m da superficie do solo, a condutividade do solo sobre a vala foi aproximadamente 2 a 3 vezes superior a obtida na linha sobre a estrada, margeando a area de deposicao. Os maiores valores de condutividade aparente puderam tambem ser relacionados as maiores concentracoes de cromo na agua subterrânea atraves de dados obtidos do trabalho de investigacao direta (analise quimica da agua coletada em quatro pocos de monitoramento realizados pela SEMA). Os ensaios realizados na area comprovam a necessidade de se manter um monitoramento constante da regiao pela possibilidade de migracao lenta dos residuos para outras areas adjacentes aquela do deposito interditado em regioes com densidade populacional maior e sem conhecimento dos perigos da utilizacao da agua do lencol freatico.

Gestão participativa na recuperação de área degradada pela agricultura

Researchers at Federal University of Mato Grosso (UFMT) subsidized a strategy for participatory management, in order to plan and implement a degraded area recovery plan (DARP) in the permanent preservation area at the basin of the Sao Lourenco river, in Campo Verde, municipality prominent in Mato Grosso and Brazil agribusiness. Research was carried out using group dynamics that are often applied in quality management standards ISO 9001. There was little interaction between local actors in terms of implementation of environmental recovery actions. The economic cost of deployment and maintenance of DARP is a bottle neck. The lack of perspectives to consider DARP as a productive area was also limiting point in farmers perspectives. The research that UFMT undertook strengthened efforts in order to reduce degradation that currently occupies around 33% of the State of Mato Grosso.