Seasonal trends in growth and biomass accumulation of selected nutrients and metals in six species of emergent aquatic macrophytes

Abstract

Muscle Shoals, Alabama 35660, USA Growth and biomass accumualtion of selected nutrients and trace metals were monitored for six species of aquatic macrophytes during June, August and November, 1993. Plant species were cultivated in two polyculture treatments, each replicated three times. Polyculture I consisted of Scirpus acutus (hardstem bullrush), Phragmites communis (common reed), and PhaZaris mmiinaceu (canary grass). Polyculture II consisted of Trpha spp. (cattail), Scirpus atrovirens (green bullrush), and Scirpus cyperims (wool grass).Each of the six cells ( 6 x 9 x 0.6 m), was operated as a gravel-substrate, subsurface-flow wetlands in a continuous recirculating mode. At six week intervals, macro, micro and trace elements were dissolved and added to the sump of the recirculating system . On each of three sampling dates, replicate shoot and root samples were collected, segregated by species and tissue type (roots, rhizomes, stems and leaves), and prepared for gravimetric biomass estimates and chemical analysis. Tissue specific concentrations of N, P, K, Ca, Mg, Fe, Mn, Zn and Cu. were determined on each date for each species and tissue type. Results will be discussed with respect to species specific growth rates, biomass accumulation, and seasonal uptake and translocation of plant nutrients. KEYWORDSAquatic macrophytes; biomass; constructed wetlands; heavy metals; mesocosm; nutrients; root to shoot rat io; translocation; NTRODUCTION Emergent aquatic plants help to regulate water quality and concentrations of nutrients and other dissolved compounds in natural and constructed wetlands.Nutrient regulation is via plant uptake, biomass accumulation and modification of the rhizosphere to facilitate microbially mediated oxidation-reduction reactions , Brix 1993, Armstrong et ai. 1990, and Gersberg et al. 1986). Although uptake and storage of nutrients by aquatic macrophytes is relatively minor compared to storage and retention in wetland soils (Johnston 1991), their ability to assimilate and transform dissolved nutrients and other substances into stable organic compounds can result in significant improvements in the quality of surface waters. According to Reddy and DeBusk (1987), desirable traits of emergent macrophytes for waste water treatment include rapid growth, high biomass potential and the ability to assimilate and store nutrients for prolonged periods of time. Extensive data bases have been compiled which provide information related to rates of nutrient uptake, tissue specific nutrient concentrations and nutrient storage capacity for many of the floating and emergent macrophytes (Johnson 1991, Reddy andDebusk 1985). However, much of the information is derived from surface flow and natural wetland studies conducted at different locations, during different seasons and under widely differing environmental condition. In a recent technology assessment of subsurface flow constructed wetlands it was noted that there is a critical need for evaluating wetland plants other than cattails reeds and rushes (Reed 1993

Nutrient Accumulation by Phragmites australis and Phalaris arundinacea Growing in Two Constructed Wetlands for Wastewater Treatment

“…In constructed wetlands, however, the R/S ratio is usually <1.0 (Behrends, Bailey, Bulls, Coonrod, & Sikora, 1994;Bernard & Lauve, 1995). Similar results were observed in our study (Table 11.1).…”

“…Bernard and Lauve (1995) reported N concentrations between 22.0 and 46.0 g kg −1 in a system treating landfill leachate in the United States (New York). Behrends et al (1994) reported values between 22.0 and 33.0 g kg −1 in experimental constructed wetlands in Alabama, and Hurry and Bellinger (1990) found nitrogen concentrations up to 45.0 g kg −1 in treatment wetland in England. In enrichment experiments, Dubois (1994) reported the range of 16.0-36.0 g kg −1 .…”

Plants used in constructed wetlands with horizontal subsurface flow: a review

“…Studies have shown that Phalaris increases its aboveground biomass as a result of higher nutrient supply (Kätterer & Andrén, 1999;Green & Galatowitsch, 2001). The same phenomenon has been reported from HF CWs where aboveground biomass is substantially higher than belowground biomass (Behrends et al, 1994;Bernard & Lauve, 1995;Vymazal & Kröpfelová, 2005, 2008a.…”

“…However, at present, Scirpus is mostly Stormwater runoff Taiwan Kao et al (2001) Airport runoff UK Worrall et al (2002) Switzerland Röthlisberger (1996) Nursery runoff Australia Headley et al (2001) Agricultural runoff China Zhou et al (2004) Hydrobiologia (2011 used in North America, Australia and New Zealand (Table 5) (e.g. Behrends et al, 1994;Tanner, 1994;Wallace & Knight, 2006;Kadlec & Wallace, 2008 …”

Water and Air Quality Performance of a Reciprocating Biofilter Treating Dairy Wastewater

“…However, subsurface wetlands can have low nitrification rates due to low dissolved oxygen concentrations (Behrends et al 1996, USEPA 1993. A new type of subsurface wetland (or biofilm reactor) has been developed by the Tennessee Valley Authority (TVA) that achieves aeration by alternately draining and filling subsurface-flow constructed wetland basins to draw air into contact with biofilm on rock aggregate.…”