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Marine dissolved organic matter: Isolation, adsorption and role in primary fouling.

Edwards, Raymond. (1982) Marine dissolved organic matter: Isolation, adsorption and role in primary fouling. Doctoral thesis, University of Surrey (United Kingdom)..

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Humic materials, which have been implicated in a number of adsorption processes in the marine environment, were isolated from seawater using three extraction procedures (adsorption onto XAD-2 resin, ultrafiltration and chloroform-emulsion extraction). XAD extraction appeared to be best suited to the isolation of fulvic acids whilst high molecular weight components were best extracted using ultrafiltration. The chloroform-emulsion technique may be used to extract the surface-active humic materials. These extracts were shown to be capable of adsorbing to hydrophilic and hydrophobic substrates and more detailed adsorption characteristics (adsorption isotherms; effect of pH, ionic strength, temperature and surface area on adsorption) were determined using silver iodide powder as the adsorbent. These adsorption studies reflected the polydisperse and polyelectrolyte nature of the extracts. The use of silver iodide allowed the infrared examination of adsorbed materials from these experiments and a comparison with an adsorbed film formed from unfractionated seawater was made. Contact angle data showed that hydrophilic and hydrophobic substrates remained or became hydrophilic after adsorption of some of the extracts on their surfaces. These adsorbed layers were shown to inhibit the attachment of a marine pseudomonad (NCMB 2021), as shown for a clean hydrophilic substrate and this was in marked contrast to high numbers of attached organisms on a clean hydrophobic substrate. It is suggested that the major components of adsorbed "conditioning" films formed in vivo are humic acids with fulvic acids and lipids being minor components. It is further suggested that adsorbed materials may not play an active role in bacterial attachment, it may simply be that macromolecule adsorption precedes it in nature.

Item Type: Thesis (Doctoral)
Divisions : Theses
Authors :
Edwards, Raymond.
Date : 1982
Contributors :
Additional Information : Thesis (Ph.D.)--University of Surrey (United Kingdom), 1982.
Depositing User : EPrints Services
Date Deposited : 22 Jun 2018 13:00
Last Modified : 06 Nov 2018 16:52

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