SUMMER BIOMASS OF AQUATIC MACROPHYTES IN RELATION TO SEDIMENT CHARACTERISTICS IN LAKE AINO-NUMA, MIYAGI

Abstract

Biomass of aquatic macrophytes and selected environmental factors were measured in August 1979 for 51 quadrats in Lake Aino-numa, Miyagi ; 21 quadrats for helophyte and 30 quadrats for hydrophyte communities. Dominant helophyte species included Zizania latifolia, Carex faponica, Equisetum limosum, Phragmites communis and Scirpus fluviatilis. Dominant hydrophyte species included Spirodela polyrhiza (free-floating) ; Trapa bispinosa, Nelumbo nucifera and Hydrocharis dubia (floating leaved) ; Potamogeton maackianus, Ceratophyllum demersum and Hydrilla verticillata (submerged). The average total biomass was 630,286,525 and 114 gm^<-2> for emergent, floating leaved, submerged and freefloating types, respectively. Total nitrogen and available phosphorus in the soil showed positive correlations with total biomass of helophyte communities, while in hydrophyte communities soil conductivity and available phosphorus showed negative correlations with total biomass.