Assessment of particulate organic matter in river water

Abstract

Particulate organic matter in a downriver riffle of the Grand River, the largest Canadian Great Lakes tributary, was studied between June 1970 and April 1972. In winter and spring, concentrations of particulate organic matter (1.0–26.2 mg/l) varied with river flow. High summer levels (3.4–12.7 mg/l) were attributable to high autochthonous primary production. Mean chlorophyll a concentration in summer (29.8 mg/m3) was nearly 15 times higher than in winter, and 8 times the spring mean level. High algal cell counts (15,000–19,000 cells/l) also occurred in summer. Autochthonous and allochthonous contributions to the total particulate organic carbon input to the river in summer were estimated by daily organic input and river flow relationships, carbon to chlorophyll a and to pheopigments ratios. The allochthonous source accounted for 21.5% of the total organic carbon while the autochthonous contributed the remaining 78.5%. The latter included living algae (23.0%), senescent plant material (30.3%) and detritus (25.2% — including microbes). The study establishes a new approach whereby the various components of particulate organic matter in river water can be indirectly partitioned and their biomass estimated by using quantitative relationships among readily obtainable parameters of river flow, standing biomass, chlorophyll a and pheopigments.

Particulate organic matter in a mountain stream in the south-western Cape, South Africa

“…All of these authors felt that ATP content and/or heterotrophic respiration rates are more accurate indicators of food quality; these factors have not yet been investigated for BOM in Langrivier. Liaw & MacCrimmon (1977) reported that high C: N ratios (18-45) of BOM in streams are usually associated with fresh plant residues or particulate organic matter of terrestrial origin. In a mature river, they recorded their highest values (9.5) during winter and spring run-off, when organic material was washed in from the land.…”

“…Over the last two decades a considerable body of knowledge has accumulated on various aspects of the biotic processes in such streams, with particular attention being paid to the input of allochthonous organic matter (Winterbourn, 1976;De La Cruz & Post, 1977;Liaw & MacCrimmon, 1977;Blackburn & Petr, 1979;Bird & Kaushik, 1981;Webster & Waide, 1982;Connors & Naiman, 1984), the fate of this material in the stream (Mathews & Kowalczewski, 1969;Fisher & Likens, 1973;Petersen & Cummins, 1974;Malmqvist et al, 1978;Naiman & Sedell, 1980;Short & Ward, 1980), and the food and feeding adaptations of the stream fauna (Minshall, 1967;Anderson et af., 1978;Anderson & Sedell, 1979;Wakefield et al, 1980;Minshall et al, 1982;Winterbourn, 1982a, b;Taylor & Roff, 1984). Several authors have also dealt with the capacity of streams to retain allochthonous detritus (Naiman & Sedell, 1979a;Minshall et al, 1983;Rounick & Winterbourn, 1983;Speaker et al, 1984), and the process of formalising the description and sampling of this material has begun (Boling et al, 1975;Naiman & Sedell, 1979a;Vannote et al, 1980;Minshall et al, 1982).…”

Dynamics of seston constituants in the Ari�ge and Garonne rivers (France)

“…These improve the understanding of the biogeochemical studies, often assessing the exports to the oceans cycles in rivers . While the first studies were mainly and lakes (Cahill, 1977 ;Martin & Meybeck, concerned with the geochemistry of large rivers 1979 ; Meybeck, 1982 ;Ryding, 1988) and to the (Livingstone, 1963), more recently interest has allochthonous and autochthonous origins of the 1 84 organic matter (Liaw & Mc Crimmon, 1977 ;Richey et al, 1980 ;Dessery et al, 1984a), rarely associated element cycles and ecological functioning (Dessery et al, 1984b). Budgets of carbon and organic matter were studied in the downstream part of the Garonne (Cauwet & Martin, 1982 ;Relexans & Etcheber, 1982), while in the middle part of the river research was mainly oriented geochemically (Probst, 1985) .…”

Compositions and fluxes of particulate organic material in the Amazon River1

“…The typical range of atomic C : N values for riverine POM (1 O-12) closely matches that of soil organic matter (Meybeck 1982), suggesting a predominantly allochthonous source for most of the world's rivers. Other forms of POM also are present at least seasonally in some rivers, as indicated by high C : N values (2 20) typical of relatively unaltered vascular plant detritus (Liaw and MacCrimmon 1977;Naiman and Sedell1979) or significant concentrations of photosynthetic pigments characteristic of phytoplankton or periphyton (Liaw and MacCrimmon 1977). With a few exceptions (e.g.…”