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Origin and Formation of Organic and Inorganic Particles in Aquatic Systems
Published in Roger S. Wotton, The Biology of Particles in Aquatic Systems, 2020
G. Milton Ward, Amelia K. Ward, Cliff N. Dahm, Nicholas G. Aumen
The decomposition of estuarine macrophytes has received more extensive study than that of algae. Studies have dealt with factors regulating decomposition rates,81–83 structural changes and nutrient losses/gains from decomposing material,84–87 and the nutritional potential of macrophyte detritus for consumers.83,88,89 Much of the information on estuarine macrophyte processing was summarized in the second Detritus Symposium and published in the Journal of Marine Science (volume 35, 1984). The pattern of macrophyte decomposition is similar to that found in terrestrial plant material. There is a rapid loss of soluble organic matter in the early stages of decomposition, followed by a rapid colonization of the detritus by microbes and mass loss due to microbial utilization. Finally, there is a period of reduced rate of mass loss of the remaining refractory portions of the macrophyte tissue.
Soil Quality: Carbon and Nitrogen Gases
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Soils and Terrestrial Systems, 2020
Philippe Rochette, Sean McGinn, Reynald Lemke
Carbon is a major constituent of biomass and soil organic matter. However, more than 99% of global carbon is locked into sediments and fossil forms and is not available for biological processes. The small remaining active fraction of global carbon transits between atmospheric CO2, biomass and soil organic matter, and detritus in the so-called carbon cycle (Figure 1). The carbon cycle is driven by photosynthetic fixation of atmospheric CO2 by plants. In global terrestrial ecosystems, it is estimated that plant photosynthesis fixes more than 200 Gt of CO2 every year.[1] Eventually, similar amounts are returned to the atmosphere by the respiration of animals and by the aerobic heterotrophic decomposition of soil organic matter and plant litter. In the absence of oxygen and other electron acceptors, CH4 is the final product of soil organic matter decomposition. Human activities, including changes in land use and soil management, are contributing to unprecedented rapid increases in atmospheric CO2 and CH4 concentrations, which may result in important modifications of the Earth’s climate. In dry soils, auto-oxidation of organic compounds can produce carbon monoxide (CO). Carbon monoxide can also be biologically oxidized to CO2 in moist but well-aerated soils.
The Ecological Significance to Fisheries of Bottomland Hardwood Systems: Values, Detrimental Impacts, and Assessment: The Report of the Fisheries Workgroup
Published in James G. Gosselink, Lyndon C. Lee, Thomas A. Muir, Ecological Processes and Cumulative Impacts, 2020
H. Dale Hall, Victor W. Lambou, Paul Adamus, James Brown, C. Fred Bryan, Ellis Clairain, Fred Dunham, Gerry Horak, Joseph Jacob, Richard Johnson, Albert Korgi, William Kruczynski, Edward Smith
We identified the importance of vegetational dominance in bottomland hardwood systems to fishes for sites of egg deposition, cover for larval and juvenile fishes, production of plankton for nutrition of the young and detrital material for the base link of the food chain and a direct food source for crawfish. Hall (1979) and Gosselink et al. (Chapter 17) pointed out the importance of detrital export to the sustenance of stream fisheries during the non-flood season. The basic premise is that in a bottomland hardwood system, detritus is the source of nutrient introduction that feeds the aquatic ecosystem. Not only does detritus provide the base link of the food chain, it also aids in erosion control through buffering the “splash” effects of rainfall on the soil. This, in turn, contributes to good water quality that is important to sensitive egg, larval, and juvenile fishes.
Shoot litter breakdown and zinc dynamics of an aquatic plant, Schoenoplectus californicus
Published in International Journal of Phytoremediation, 2018
Silvana Arreghini, Laura de Cabo, Roberto José María Serafini, Alicia Fabrizio de Iorio
Schoenoplectus californicus is indigenous to coastal regions from southern North America (Mason 1957) south to Chile and Argentina [see (Wagner, Herbst, and Sohmer 1990)] and forms monoespecific stands known as “marshes.” In marshes, the dynamics of the aboveground biomass of Schoenoplectus californicus depends on tidal cycles (Pratolongo, Kandus, and Brinson 2008). Since many phytoremediation studies focus on phytoextraction of metals and/or stabilization in sediments, it is very important to evaluate the relationship between the decomposition rates of the plant biomass and the release of the pollutants originally immobilized. Frequently, most of the organic matter production of aquatic macrophytes is decomposed before it enters the food chain (Mitsch and Gosselink 1993). Decomposition of organic matter is one of the most important processes that determines the structure and function of aquatic systems, since it is the process that controls the cycling of C and the availability of nutrients. The process of detritus decomposition in aquatic systems is regulated by environmental factors, such as temperature, redox conditions, nutrient concentration, and the quality of the detritus (nitrogen, phosphorus, lignin and/or polyphenol content, etc.), and it is affected by the presence of degradation agents like shear stress, fungi and shredders (Gessner 1999). Several authors have studied the influence of these factors on the decomposition rate of organic matter (Lambers, Stuart Chapin III, and Pons 1998; Kalburtji, Mosjidis, and Mamolos 1999; Cross et al. 2003; Lecerf et al. 2007; Balasubramanian et al. 2012). Some studies have reported a decrease in the rate of decomposition of detritus in soils [see (Chew, Obbard, and Stanforth 2001; Boucher et al. 2005)] and streams [see (Sridhar et al. 2001; Duarte et al., 2008)] that are contaminated with metals due to the negative effect on the diversity and activity of decomposing microorganisms.