standardization of environmental data and information - International ...

To obtain quality data on metals in pore water and the water
column, ultraclean techniques should be used for measurement and to
permit calculation. Samples would have to be collected by trained technical
staff before they were sent to laboratories capable of doing ultraclean
measurements.
In addition, core depths would have to be specified. For example, a
flux calculation theoretically required only the gradient at the
sediment/water interface, including the bottom water and the 0-1 cm layer.
However, if the rest of the core was discarded, some important part of the
profile might be missed. Thus, sediment intervals must be specified,
though not necessarily a large number.
Measurements would not have to be taken too often: before and
after mining should be sufficient to assess the bottom flux, with no need for
a time series. Flux measurements could be done near the mooring
locations.
As to chemical parameters, he advocated the use of standard,
commonly used methodologies. Oxygen could be measured by a Winkler
system device or an electrode. Oxygen demand, if it were to be measured,
was usually assessed by a time-series study. Oxygen reduction potential
(ORP), suggested as a parameter in some literature, could be measured by
electrode. Nitrate, nitrite, phosphate and silicate could be done by
standard methods using colorimetry or a similar technique, and alkalinity by
titration. The procedure for turbidity was straightforward. For metals,
atomic absorption analysis (AAA) could be used, although ICP-MS
(inductively coupled plasma - mass spectrometry) would probably be
preferable, as it was cheap and accurate.
SUMMARY OF DISCUSSION ON CHEMICAL PARAMETERS
Placement of moorings
Professor Craig R. Smith raised a point about the location of
moorings for monitoring instruments and the number of current meters they
should hold. He noted that he had suggested a change in the
recommendations made by physical oceanographers at the 1998 Sanya
Workshop, 1 relating to the distribution of data collection that they saw as
useful for understanding the current regime in a claim area of 150,000
288 INTERNATIONAL SEABED AUTHORITY