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identifying species at various locations would suffice for that purpose. His
point was that sampling difficulties made assessment difficult at this stage
and that, in order for sampling to be useful, more of it had to take place.
Endorsing Rex’s plea for molecular genetic studies of deep-sea
organisms, Smith cited two arguments: (1) Many species might be
identifiable only by using molecular techniques, which might cut the time
required to differentiate species and understand distribution patterns. (2)
By using population genetic models, estimates of population size could be
made, based on genetic diversity within a population. Thus, some of the
concerns that had been voiced could be addressed without exhaustive
sampling, using population genetic techniques.
Rex added that this approach could also provide information about
dispersal, which was a factor in recolonisation, and about the relationships
between larger regional pools of species and local populations. As to how
sampling might be improved, he said that researchers faced a dilemma.
From what had been said about sampling in nodule fields, it seemed that
box-core sampling worked well but the sample size was small. The way to
learn more about the regional species pool would be to use epibenthic
sleds and take a lot of samples. These would be bigger samples that could
not be used to quantify by biomass and density but that would give a clearer
indication of the species pool. That technique was difficult to employ in this
environment, however, because the nodules tore up the material and would
probably tear up the dredge. Thus, he guessed the answer lay in more box
cores.
Smith observed that a lot of engineering expertise had gone into the
design of mining heads to separate nodules from sediments. As using sleds
to sample sediments without nodules raised the same problem in reverse,
the Workshop might recommend that thought be given to developing a
large-scale sampling device in the form of an epibenthic sled that would
bring up sediment without having the nodules grind the animals to bits,
thereby improving the analysis of distribution patterns.
Reinforcing this point, another participant said the problem he had
found, when working on CCFZ polychaetes, was that there were never
enough specimens in a box core, making it difficult to investigate
biodiversity as opposed to ecology. Working with box cores was a nightmare
when asking questions about regional ranges of species. A sled-type
sampler was desperately needed.
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