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standardization of environmental data and information - International ...

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Regarding the sampling protocols utilized for mei<strong>of</strong>auna, he said<br />

DISCOL had sampled at 1 centimetre intervals up to 6 cm; NOAA at 0.5 cm<br />

intervals up to 3 cm; JET at 0.25 cm intervals up to 1 cm, then 0.5 cm<br />

intervals up to 3 cm <strong>and</strong> 1 cm intervals up to 5 cm; IOM at 0.5 cm up to 3<br />

cm <strong>and</strong> 1 cm intervals up to 6 cm, <strong>and</strong> INDEX at 2 cm intervals up to 10 cm.<br />

The Indian group had chosen broad intervals because it did not have access<br />

to a multicorer. Once again, there was non-uniformity in the sampling<br />

protocols for mei<strong>of</strong>auna. Yet, the mei<strong>of</strong>auna was a good indicator <strong>of</strong> impact<br />

from mining for nodules. Many biologists said that the top 2 cm would be<br />

critical, as the largest numbers <strong>of</strong> mei<strong>of</strong>auna in the sediment column were<br />

located there <strong>and</strong> mining would disturb the top 5 to 10 cm.<br />

He next cited an example <strong>of</strong> the measurement <strong>of</strong> water content<br />

from three samples taken at the same location but using two different<br />

coring devices. The <strong>data</strong> from a box core, even taking the averages at three<br />

different levels in the sediment core, indicated that the water-content levels<br />

were extremely heterogeneous, with no particular pr<strong>of</strong>ile or trend. The<br />

multicorer, however, showed a clear downward trend in water content.<br />

Thus, different samplers gave different patterns <strong>of</strong> <strong>data</strong> for samples<br />

collected at the same location.<br />

In another comparison, he cited sediment-density estimates from<br />

Indian <strong>and</strong> Japanese sites using four different methods involving the<br />

removal or non-removal <strong>of</strong> air from the sediment: (1) measurement without<br />

creating a vacuum in the sediment, where the sample was dried but<br />

exposed for some time; (2) similar measurement where the sample was<br />

dried but not exposed; (3) measurement by creating a vacuum <strong>and</strong><br />

exposing the sample for some time, <strong>and</strong> (4) similar measurement but<br />

without exposing the sample. Again, different values had been obtained for<br />

sediment density. Probably the ideal method would have been to use a<br />

vacuum device, dry the sediment, not expose it to the atmosphere, remove<br />

all moisture, remove all air <strong>and</strong> then measure the density <strong>of</strong> the sediment.<br />

He then compared the scales <strong>of</strong> the BIEs. Their duration had been<br />

between 18 <strong>and</strong> 88 hours, whereas the expected duration <strong>of</strong> mining was<br />

300 days/yr. The experiments covered areas <strong>of</strong> 33-141 km 2 , whereas the<br />

expected area <strong>of</strong> mining was about 300-600 km²/yr. The recovery rate in<br />

the experiments had been 0.77-1.4 m³/minute, while the expected rate<br />

during mining was about 37.5 m³/min. Thus, the experiments were orders<br />

<strong>of</strong> magnitude smaller than mining, so that extrapolation <strong>of</strong> <strong>data</strong> was a<br />

question mark.<br />

INTERNATIONAL SEABED AUTHORITY 495

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