Accession Number : ADA166657
Title : Effects of Sediment Composition on Growth of Submersed Aquatic Vegetation
Descriptive Note : Final rept.
Corporate Author : ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
Personal Author(s) : Barko, John W ; Smart, R M
Report Date : Jan 1986
Pagination or Media Count : 44
Abstract : Experiments with two submersed aquatic macrophytes, Myriophyllum spicatum L. and Hydrilla verticillata (L.f.) Royle, grown on 40 different sediments from 17 geographically widespread North American lakes, indicated tenfold and twentyfold declines in growth with increasing sediment organic matter up to a concentration of about 20 percent dry sediment mass. Poor growth was obtained also on inorganic sediments with a sand fraction exceeding 75 percent dry sediment mass. Diminished growth on organic sediments occurred at low values of sediment density, and on sands at high values of sediment density. Differential centrifugation of organic sediment, facilitating an increase in sediment density with no change in organic matter content, stimulated Hydrilla growth, indicating that sediment density rather than organic matter content was most influential in regulating growth. Macrophyte growth and nutrient accumulation in shoots were closely correlated, but essentially unrelated to concentrations of nutrients in shoots. Additions of phosphorus and iron in combination to organic sediments with nitrogen supplied in the overlying solution resulted in significant growth increases in Hydrilla, suggesting that diminished growth on unfavorable sediments was caused by multiple nutrient limitation. It is further postulated that variations in the ability of different aquatic macrophytes to cope with infertility or other factors associated with unfavorable sediment composition may influence the species composition of aquatic macrophyte communities.
Descriptors : *VEGETATION , *SEDIMENTS , *AQUATIC PLANTS , DENSITY , MASS , NUTRIENTS , NITROGEN , IRON , ORGANIC MATERIALS , PLANT GROWTH , VISIBILITY , ACCUMULATION , DRY MATERIALS , PHOSPHORUS , LAKES , CENTRIFUGE SEPARATION , NORTH AMERICA , INORGANIC MATERIALS
Subject Categories : Biology
Distribution Statement : APPROVED FOR PUBLIC RELEASE