BIOLOGICAL CYCLING OF MICRO-NUTRIENTS IN BRUGUIERA PARVIFLORA 63 Malays. Appl. Biol. (2008) 37(1): 63–68 * To whom correspondence should be addressed. BIOLOGICAL CYCLING OF MICRO-NUTRIENTS (Cu, Fe AND Zn) IN BRUGUIERA PARVIFLORA DOMINATED MANGROVE FOREST AT KUALA SELANGOR NATURE PARK, MALAYSIA MAHMOOD HOSSAIN 1* , SABERI OTHMAN 3 , MISRI KUSNAN 2 and JAPAR SIDIK BUJANG 2 1* Forestry and Wood Technology Discipline Khulna University, Khulna -9208, Bangladesh Tel: 880-41-721791 Ext: 228 Fax: 880-41-731244 E-mail: mahmoodhossain@hotmail.com 2 Faculty of Science, University Putra Malaysia, Malaysia 3 Faculty of Science and Technology University Pendidikan Sultan Idris, Malaysia ABSTRACT The biological cycling of micro-nutrients (Cu, Fe and Zn) was studied at the Kuala Selangor Nature Park mangrove forest, Malaysia. The total stock of Cu, Fe and Zn in standing biomass of Bruguiera parviflora saplings and trees was 1195.38 g ha -1 , 87962.30 g ha -1 and 2295.02 g ha -1 , respectively. The annual accumulation of Cu, Fe and Zn in plant components was 125.44 g ha -1 , 10073.63 g ha -1 and 238.55 g ha -1 , and the annual return was 79.80 g ha -1 , 790.29 g ha -1 and 178.15 g ha -1 . The calculated turnover period and absorption coefficients of Cu Fe and Zn were 15 yr, 111 yr and 13 yr; and 0.006, 0.001 and 0.003, respectively. The sequences of absorption coefficient and utilization coefficient were Cu>Zn>Fe and Zn>Cu>Fe, respectively. Key words: Biomass, litter production, micro-nutrients, mangroves, nutrient cycling INTRODUCTION Estimation of standing biomass, annual biomass increment, litter production and litter standing crop are the approaches for estimating the productivity and functioning of a mangrove forest (Ong et al., 1985; Gong and Ong, 1990). Measurement of within stand nutrient cycling could be another useful approach for estimating the same. Plants uptake nutrients from soil and translocate them to different parts to perform physiological functions (such as respiration, transpiration and photosynthesis), normal growth or to complete the life cycle (Jones et al., 1991; Marschner, 1995). During the physiological functions, a portion of the absorbed nutrients is accumulated in plant biomass and remainder are released as litter fall and dead root, which is rapidly taken up by the plants and retained within the system (Duvigneaud and Smet, 1970; Binkley, 1986). Micro-nutrient (e.g. Cu, Fe and Zn) content in plant is influenced by metabolic requirements (Baker and Walker, 1990), fluctuation of climatic condition, soil physiochemical characteristics and content of other nutrients in soil (Walbridge, 1991; Jones, 1998). The uptake, return and cycling of macro-nutrients in Avicennia marina, Rhizophora apiculata, Aegiceras corniculatum and Kandelia candel dominated stands at different mangroves have been studied (Clough and Attiwill, 1975; Aksornkoae and Khemnark, 1984; Gong and Ong, 1990; Li, 1997). But, within stand cycling of micro- nutrient in the tropical mangroves is yet to be investigated. Bruguiera parviflora is distributed throughout Southeast Asia to tropical Australia and least studied among the mangrove communities. Present study synthesized the previous and new data and estimates the biological cycling of micro-nutrients (Cu, Fe and Zn) in B. parviflora dominated tropical mangroves.