Garrett screen

Only one actual comparison of these techniques is available in the literature. Daumas et al. [13] compared the Harvey drum sampler to the Garrett screen, and found greater organic enrichment in both dissolved and particulate matter in the drum samples. The size of the difference between the two samplers suggests that the Garrett screen included 2-3 times as much water as did the Harvey drum. 

Field workers soon found that the choice of screen material, as well as the thickness of the screen, could influence the amount of surface film material recovered. The Garrett screen was also a fair-weather collection method, since such collection had to be done from a small boat, away from the influence of the research vessel. A wide variety of devices and materials were soon tested and compared [125-128]. The general conclusion was that each device or samphng material collected a shghfly different selection of compounds from the surface layer, so that direct comparisons between different collection protocols could... 

Much of the mathematics involved in calculating screen characteristics came from World War II military-based operations analysis and research, where it was important for design of radar, antiair and antisubmarine warfare systems and operations (Garrett and London, 1970). 

Other experimental efforts focused on the collection of ocean surface samples in order to investigate properties of the marine microlayer in the laboratory. Samples were retrieved using either inert screens (Garrett 1965) or drum-type samplers (Carlson et al. 1988, Frew and Nelson 1992). 

Lipid material was extracted from the seawater and screen samples by coprecipitation with ferric hydroxide. Back in the laboratory, the precipitate was acidified and extracted with chloroform. After hydrolysis and methyla-tion of the extract with BF /MeOH, the relative proportions of fatty acids and alcohols in each of the samples was determined by GLC. A distribution of fatty acids centred on C,6 o [i.e., CH3(CH2)i4COOH, palmitic acid] t3rp-ical of planktonic lipids was found as illustrated in Fig. 5a for a typical surface sample. Garrett (1967c) noted that for some samples, the lipid extract was dominated by a high molecular weight material, apparently hydrocarbon, which was not surface active. 

Collection of samples of the sea surface microlayer can be performed from a rowed dinghy, at least one mile upwind of the ship. The method usually used is the metallic steel screen technique described by Garrett (1965). 

Collection of sea surface microlayer (lOO— 150 /tm) by a metallic screen and subsurface water with Van Dome bottles no filtration, coprecipitation with ferric hydroxide followed by an extraction with chloroform IR, GLC Bay of Panama total hydrocarbons isolation of a hydrocarbon substance (M = 400), with a computed formula C29H52 Garrett (1967)... 

Blagg, J., Collins, I., Garrett, M.D., and van Montfort, R.L. (2013) Fragment-based screening maps inhibitor interactions in the ATP-binding site of checkpoint kinase 2. PLoS One, 8 (6), e65689. 

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