Decomposition and mineralization of Eichhornia crassipes litter under aerobic conditions with and without bacteria

Abstract

The water hyacinth (Eichhornia crassipes (Mart.) Solms.) plants in lakes and reservoirs have gained considerable attention in tropical and sub-tropical parts of the world due to its rapid growth. The amount of nutrients released from the dead plant materials is of particular interest. Thus, decomposition of water hyacinth plant parts under aerobic conditions was studied in the laboratory. Roots, petioles, and leaves of water hyacinth were enclosed separately in one litre polypropylene bottles which contained 500 ml of lake water. To study the influence of bacteria on the decomposition, antibiotics were added to half of the bottles. We observed that decomposition of leaves and petioles without antibiotics were relatively rapid through day 61, with almost 92.7 and 97.3% of the dry mass removed, respectively. Weight loss due to bacterial activities during 94 days decomposition was 22.6, 3.9, and 30.5% from leaf, petiole, and root litter. Decomposition of litter in lake water indicated that after 94 days 0.6, 0, and 0.6 g m )2 of leaf, petiole, and root N was dissolved in leachate, while 23.1, 14.4, and 6.0 g m )2 of leaf, petiole, and root N was either volatilized or remained as particulate organic N. Moreover, 0.2, 0, and 0.1 g m )2 of leaf, petiole, and root P remained dissolved in the leachate, while 3.1, 3.4, and 1.1 g m )2 of leaf, petiole, and root P was either precipitated or remained as particulate organic P. The carbon dynamics during the decomposition indicated that 7.4, 28.8, and 3.7 g m )2 of leaf, petiole, and root C remained dissolved in the leachate after 94 days while 228.0, 197.6, and 107.4 g m )2 of leaf, petiole, and root C was either diffused or remained as particulate organic C. These findings are useful for quantifying the nutrient cycles of very shallow lakes with water hyacinth under aerobic water environment. Further examination of the fate of the plant litter as it moves down in deep anaerobic water environment, is necessary to understand the leaching process better.

Decomposition Dynamics ofTypha angustifoliaunder Aerobic Conditions

“…9, 2016 was minimal during this period. 11,23 The mass loss during this time is associated with the release of cytoplasmic fractions and hydrosoluble compounds that were present in the macrophyte. 24,25 The release of phosphorus during the initial decomposition period is linked to the loss of soluble phosphorus that had accumulated in plant tissue vacuoles.…”

“…At the end of 90 days, 234 mg of chloramphenicol was added to each chamber containing samples treated with antibiotics to suppress bacterial growth. 11,14 The decomposition experiment was conducted for 120 days, and samples from each treatment were randomly collected at eight sampling times: 1, 3, 7, 15, 30, 60, 90 and 120 days.…”

“…The detritus decomposition was exponentially modeled as proposed by Gamage and Asaeda: 11 W t = W 0 e −kt (1) where W t is the dry weight at time t, W 0 is the initial dry weight and k is the decay rate constant. By using this model, we assumed that the decomposition process follows firstorder kinetics and that the decomposition rate constant at time t is proportional to the weight at time t. The decay rate was calculated using the equation 1.…”

“…[11][12][13] The main changes in nutrient forms occur during the catabolism stage of the decomposition process, with formation of phenolic compounds, humic substances, and phosphorous derivatives. Microorganisms incorporate inorganic nutrients from senescent biomass and exert an overall impact on both the internal wetland nutrient dynamics and overall nutrient sequestration, both of which are important functions of wetlands in the landscape.…”

Potential of Eichhornia crassipes for biomass refining

“…Much research has been devoted to the decomposition of water hyacinth [3,5,8,11,12,13,15,17,18,25,26,41]. Studies have shown that bacterial decay activity occurs most rapidly within the first 14 days of decomposition [8,11,13,25,41].…”