standardization of environmental data and information - International ...

edeposit on the surrounding seafloor, burying the
sediment/water interface and biota under sediment blankets
ranging in thickness from a few grains to several centimetres. A
diffuse plume will persist in the benthic boundary layer for
weeks to months, potentially travelling hundreds of kilometres. 4 .
iii. In the surface ocean, release of bottom water entrained with
lifted nodules, as well as sediments and nodule fragments, may
enhance nutrient and heavy-metal concentrations, and reduce
light levels; these alterations may affect, among other things,
rates of primary production, food-web dynamics and survival of
larval fish in oceanic surface waters. Settling of sediments and
nodule fragments from this discharge into the oxygen-minimum
zone may lead to the release of heavy metals.
iv. The discharge of tailings from nodule processing will (by future
ISA regulations) occur in the deep ocean below the oxygenminimum
zone (i.e., typically below a depth of 1200 m). Once
again, a large sediment plume will be formed, altering
suspended particle concentrations, potentially influencing midwater
food webs and yielding sediment redeposit ion on the
underlying seafloor. 5
Following several decades of nonexclusive prospecting for
polymetallic nodules at the abyssal seafloor, mining claimants are now
entering the exploration stage of nodule mining. In accordance with
regulations developed by ISA 63 (discussed in chapter 1 above), exploration
is the
“searching for deposits of polymetallic nodules in the Area
with exclusive rights, the analysis of such deposits, the
testing of collecting systems and equipment, processing
facilities and transportation systems, and the carrying out of
studies of the environmental, technical, economic,
commercial and other appropriate factors that must be
taken into account in exploitation” (regulation 1.3(b)).
Exploration can occur only after approval by ISA of an application
from the potential contractor explaining, among other things, (1) a plan of
work, (2) what baseline studies will be conducted and (3) a preliminary
assessment of possible environmental impacts of the proposed exploration
activities. The plan of work for exploration will be for 15 years, and may be
extended for an additional 5 years. The size of exploration areas will not
exceed 150,000 km 2 , i.e., an area equivalent to a square of 387 km on a
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