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e measured must be specified. I recommend a minimum of four stations,
corresponding in number and location to those recommended for seafloorcommunity
studies (see section 2.4.1 above). Because Pb-210 mixed layer
depths appear to be shallow in the CCFZ 22 , I also recommend that the
depth levels within cores for Pb-210 assays be more concentrated near the
sediment/water interface (i.e., at 0-0.5, 0.5-1.0, 1.0-1.5, 1.5-2.5 and 2.5-5
cm). Because of the long characteristic time scale of excess Pb-210
activity (~100 years), bioturbation intensities need to be evaluated only
once at each station for baseline purposes.
2.6. Sedimentation
The baseline requirement for evaluation of sedimentation, as
recommended by LTC, is as follows (paragraph 8(f)):
“gather data of the flux of materials from the upper-water
column into the deep sea”.
The Sanya Workshop recommended that two sets of sediment traps
be deployed on two moorings for at least 12 months. One trap on each
mooring should be at a depth of ~2000 m to characterize mid-water particle
flux and one trap on each mooring should be ~500 m above the seafloor
(and outside of the benthic boundary layer) to evaluate deep-particle flux.
Traps should sequentially sample at no longer than one-month intervals.
Traps may be deployed on the current-meter moorings. More detailed trap
protocols and the measurements to be made on the collected material
must be specified. I suggest adopting the JGOFS protocols 23 for deep
sediment traps, an d that variables measured include the fluxes of total
mass, particulate organic carbon mass, calcium carbonate, biogenic silica
and excess Pb-210 (again using JGOFS protocols).
3. Other Issues for Baseline-Data Collection
3.1. Frequency, duration and spatial distribution
Variability in baseline conditions within claim areas can result from
seasonal, interannual (e.g., El Niño, La Niña) and decadal (e.g., climatic
regime shifts) phenomena. 24 It is neither feasible nor desirable to evaluate
variations in all the baseline parameters on all these time scales, so certain
time scales must be targeted for particular parameters. Because response
times (e.g., recovery times following disturbance) are thought to be slow for
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