Biogenic mass transport in Great Lakes sediments
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Case Western Reserve University School of Graduate Studies / OhioLINK
1995
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=case1058876530 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-case10588765302021-08-03T05:31:23Z Biogenic mass transport in Great Lakes sediments Wang, Xiaosong Biogeochemistry Biogenic transport Great Lakes sediment Mechanisms of biogenic mass transport in sediment by major freshwater benthic invertebrates, Branchiura sowerbyi, Limnodrilus hoffmeisteri, Tubifex tubifex, Chironomus plumosus, Coelotanypus sp., Hexagenia limbata, Sphaerium transversum, and Anodonta grandis, have been studied using 137Cs and 22Na to trace the movement of solid particles and pore fluid in sediment. Oligochaete B. sowerbyi, L. hoffmeisteri, and T. tubifex are important sediment particle transporters. They removed sediment particles from a depth of 3-20 cm and deposited them onto the sediment surface resulting in significantly enhanced mass flux across the sediment-water interface. At a population density of 1,000/m<sup>2</sup>, B. sowerbyi removed 66.82-78.59 kg dry sediment/m<sup>2</sup>/yr; L. hoffmeisteri and T. tubifex transport 7.73-8.79 kg dry sediment/m<sup>2</sup>/yr. However, the oligochaetes did not cause significant mixing of the sediment. The mixing and feeding activities of the organisms are strongly depth dependent. Chironomids C. plumosus and Coelotanypus sp. are significant solute transporters, even though they did not mix and transport sediment particles to a significant degree. These chironomids transported solutes in the sediment mainly by constructing vertical or U-shaped burrows and irrigat ing them with the overlying water causing direct exchange of solutes between the overlying water and the pore fluid. B. sowerbyi also greatly enhanced solute flux across the sediment-water interface. H. limbata could be important in particle transport, depending on its size. S. transversum and A. grandis are less important than the oligochaetes and chironomids in terms of either particle or solute transport. Particle and solute transport models were developed to simulate biogenic mass transport processes. Methods for evaluating the model parameters were also developed. For particle transport, a dynamic mixing model predicted the tracer activity profiles in the presence of infauna. For solute transport by B. sowerbyi, the enhanced vertical diffusion model worked nicely indicating that sediment mixing by these worms could be approximated as a diffusive process. Solute transport by chironomids was better described by the radial or cylindrical diffusion model because the irrigation of their burrows caused radial diffusion across the burrow walls. Also the strong directional flow of solute in the burrows can not be described by diffusive process. However, the nonlocal exchange model using a constant α term described the solute transport in all the experiments very well except in the B. sowerbyi experiment in which a depth dependent α term was suggested. Model parameters were evaluated independently of the models. Therefore, the very good match between the modeled tracer activity profiles and the measured profiles indicated the model validity and great possibilities of applications of these models to in-situ conditions 1995 English text Case Western Reserve University School of Graduate Studies / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=case1058876530 http://rave.ohiolink.edu/etdc/view?acc_num=case1058876530 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Biogeochemistry Biogenic transport Great Lakes sediment |
| spellingShingle |
Biogeochemistry Biogenic transport Great Lakes sediment Wang, Xiaosong Biogenic mass transport in Great Lakes sediments |
| author |
Wang, Xiaosong |
| author_facet |
Wang, Xiaosong |
| author_sort |
Wang, Xiaosong |
| title |
Biogenic mass transport in Great Lakes sediments |
| title_short |
Biogenic mass transport in Great Lakes sediments |
| title_full |
Biogenic mass transport in Great Lakes sediments |
| title_fullStr |
Biogenic mass transport in Great Lakes sediments |
| title_full_unstemmed |
Biogenic mass transport in Great Lakes sediments |
| title_sort |
biogenic mass transport in great lakes sediments |
| publisher |
Case Western Reserve University School of Graduate Studies / OhioLINK |
| publishDate |
1995 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=case1058876530 |
| work_keys_str_mv |
AT wangxiaosong biogenicmasstransportingreatlakessediments |
| _version_ |
1719421239197433856 |