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Chapter 14
Biodiversity in the Deep-Sea Benthos:
Pattern and Scale. Sampling and
Analytical Problems Associated with
Assessment in Abyssal Regions
Dr. Michael A. Rex, Professor of Biology, Department of Biology,
University of Massachusetts, Boston, United States of America
Since serious interest developed during the 1960s in commercially
mining deep-sea polymetallic nodules, a great deal has been learned about
patterns of biodiversity in the deep-sea benthos at local, regional and global
scales. Biodiversity refers to the variety of living organisms. It involves all
levels of organization including genetic, population-species, communityecosystem
and landscape, each with its own components of pattern and
process 1 . The present Workshop has reviewed general patterns of
biodiversity in the deep-sea benthos, and the special problems of
measuring biodiversity and impact assessment in the abyss where mining is
planned.
1. Pattern and Scale
1.1. Genetic Level
The Regulations of the International Seabed Authority 2 do not
specifically address biodiversity at the genetic level but this could be
included in a highly cost-effective way by using the same collections of
benthos that are being used to measure community makeup. Genetic
biodiversity is an essential part of understanding the effects of mining and
other anthropogenic disturbances on deep-sea ecosystems, and developing
sound conservation protocols.
The primary evidence used for conservation of biodiversity at the
genetic level is genetic population structure, the spatial pattern of genetic
diversity within and among populations 3 . It is a critical component of
biodiversity for conservation efforts because the ability of species to adapt
to changing environments depends directly on their genetic diversity. Loss
and fragmentation of habitats reduce population size and erode genetic
variation, making populations more vulnerable to local extinction. This, in
turn, destabilizes biotic interactions within communities and depresses
INTERNATIONAL SEABED AUTHORITY 303