Water-column profiles

Figure 2. Water-column profiles from Little Rock Lake Treatment Basin in 1989. A, temperature B, dissolved oxygen C, dissolved Hg and D, particulate Hg. (Adapted with permission from reference 21. Copyright 1991...

Water Column DMS Profiles. Nguyen et al. (441 was the first to report DMS water column profiles. One profile had a maximum at 10 m, while the second profile maximum was at 30-32 m. The third profile showed a continual decrease in DMS with depth (0-130 m). They concluded from the data that DMS maximum could move vertically and might account for locally high surface DMS concentrations. 

Figure 7.8 Water column profiles of (a) dissolved organic carbon (DOC) and (b) values (particulate uranium/dissolved uranium) across the redox transition in the stratified Framvaren fjord (Norway). (Modified from Swarzenski et al., 1999.)...

Figure 34-4 Water column profiles of nitrate concentration (open symbols) and c5 N itrate (filled symbols) in the Eastern Tropical North Pacific (ETNP, coastal Baja California), Southern Ocean and North Atlantic (Sargasso Sea). The ETNP shows a large increase in c5 N i ate in the thermocline owing to local water column denitrification. The Southern Ocean shows little deviation from the global deep mean c5 N it te except at the surface, where partial NO3 assimilation leaves residual nitrate enriched in N. The North Atlantic profile shows low c5 N itrate in the thermocline owing to the nitrification of locally fixed N. Note that the ETNP profile also includes deep measurements from near Hawaii (diamonds) the smooth transition between samples at distant locations emphasizes the homogeneity of the deep Pacific.

Many Th measurements in the upper ocean indicate that it is mostly dissolved even though thorium is relatively particle-reactive because dissolved thorium grows into secular equilibrium faster than it is depleted by adsorption to particles. To determine an annual particle flux at a given location one would like to sample the ocean at the frequency of the Th half life about one month. This has been done at the Hawaii Ocean Time series (HOT) near Hawaii, and a few of the monthly profiles are presented in Fig. 6.11 (Benitez-Nelson et al, 2001). In this experiment, monthly estimates of the particulate Th flux determined by water column profiles were transformed to carbon fluxes by using measured particulate C Th ratios and compared with the carbon flux from sediment traps. The two different estimates varied by almost a factor of two, with the trap samples being lower. The largest differences were observed during times... 

Table II. Density Anomaly (ct,) Values of Characteristic Features in the Water-Column Profiles...

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