Research On Carbon Storage Of Major Aquatic Plant Communities

This paper is started from the survey of aquatic plant community of Hongze Lake WetlandReserve, based on field works and collection of relevant information and data.6kinds of wetlandaquatic plants were selected to study: Phragmites communis, Nelumbo nucifera, Alternantheraphiloxeroides, Ceratophyllum demersum L., Potamogeton crispus, Lemnaminor. To studydifferent aquatic plant communities of biomass, carbon content and soil carbon content in fourseasons, spatial differences and seasonl dynamics of carbon storage. The study contents and dataof Hongze Lake Wetland were enriched. Main findings are as followed:（1）Plant biomass in Hongze Lake Wetland were changed in seasons, in general, the plantbiomass was higher in summer and autumn due to the growth period. On the contrary, the plantbiomass was lower in the spring and winter. The average plant biomass was, Phragmitesaustralis> Nelumbo nucifera> Potamogeton crispus>Alternanthera philoxeroides>Ceratophyllum demersum L.> Lemnaminor. For the emergent plants, the root-shoot ratio ofPhragmites australis was2.96, the root-shoot ratio of Nelumbo nucifera was0.63.（2） The average soil contents of six aquatic plant communities were decreased with theincreasing depth of the soil. The average soil contents of Phragmites australis community was thehighest; besides, the average soil contents of Nelumbo nucifera community was higher than otheraquatic plant communities. So, the emergent plants with developed root systems could accumulateorganic deep into the45cm depth of soil. Average soil contents of aquatic plant communities were:Phragmites australis（4.69%）> Nelumbo nucifera（3.50%）>Alternanthera philoxeroides（2.52%）> Ceratophyllum demersum L.（2.28%）> Lemnaminor （1.75%）> Potamogeton crispus（1.50%）.（3） The average plant carbon concentration of Phragmites australis community was themaximum among these plant communities, it reached53.68%, and there was no significantdifferences among other plant communities, it was the range of42.07%-44.96%. The minimumcarbon concentration was42.07%on Ceratophyllum demersum L. community. In the differentseasons, the change of carbon concentration of different plant communities was relativelyobvious. Meanwhile, for the emergent plants, the carbon concentration of above-ground andunderground was different; it was changed with the seasons.（4） The soil carbon storage was: Phragmites australis(5.32kg m^-2)> Nelumbo nucifera(3.83kg m^-2)> Ceratophyllum demersum L.(2.35kg m^-2)> Alternanthera philoxeroides(2.11kg m^-2)> Lemnamino(r1.56kg m^-2)> Potamogeton crispus1.33kg m^-2). In april, the soilcarbon storage of Phragmites australis community was the highes(t7.69kg m^-2)，the soil carbonstorage of Alternanthera philoxeroides community was higher than Ceratophyllum demersum L.community. In july, the soil carbon storage of Nelumbo nucifera community was higher thanPhragmites australis community, the value was the maximun(4.80kg m^-2),and the minimum was Lemnaminor community(1.70kg m^-2). In September, the soil carbon storage had littledifferences.in December, the soil carbon storage of Phragmites australis community was thehighest, as well as the Nelumbo nucifera community, otherwise, others were minimum of theirown in a year.（5） the maximum value of plant carbon storage per unit area was Phragmites australiscommunity and the minimum was Lemnaminor community. The average of plant carbon storageper unit area of six aquatic plant communities was: Phragmites australis community(2.27kg m^-2)> Nelumbo nucifera community(0.51kg m^-2)> Potamogeton crispus community(0.18kg m^-2)> Ceratophyllum demersum L. community(0.11kg m^-2)>Alternanthera philoxeroidescommunity (0.09kg m^-2)>Lemnaminor community(0.05kg m^-2).