EPILOGUE: EXPLORATION, OBSERVATION AND EXPERIMENTATION
475
from a surface ship. This technology has developed
rapidly over the last ten years, and is used extensively –
for instance, to study scavenging by deep-sea crustacea
and fish, or to measure temporal variables such as the
oxygen consumption of the sediment community (see
Chapter 11). The use of landers will continue to provide
a valuable platform for deep-sea experimentation.
Possibly the greatest advance for deep-sea experimental biology has been the development of the
manned submersible. In its traditional form this is a
vehicle that will take pilots and observers to the deepsea bed, where they can conduct in situ experiments
as well as making observations. Even more recent
is the development of Remote Operated Vehicles in
which the vehicle is operated by a pilot and observer
on the mother vessel, obviating the potential dangers
of subjecting them to pressures of several hundred
atmospheres in the ocean. ROVs have developed so far
in the last five years that they have almost the same
capability as manned submersibles. Last of the new
batch of engineering technologies is the ‘Autonomous
Underwater Vehicle’, which is able inter alia to map
and photograph the seafloor. Such vehicles may well
herald a new era of deep-sea exploration.
Submersibles have been critical to the success of
observation and experimentation at hydrothermal vents.
Without the ability to work at a scale of less than
one metre, considerably less would have been achieved
at hydrothermal vents. The physiology of the unique
organisms at vents is now well understood (Van Dover,
2000), while the microenvironment (Luther et al., 2001)
and the most intractable of processes, dispersal, are
now being unravelled (Marsh et al., 2001; Pradillon
et al., 2001). Vents are even known to emit light (White
et al., 2000), leading to speculation on the origins of
photosynthesis, and even life itself.
It is always possible to plan and execute experiments,
but it is often the serendipitous observation that leads
to some of the most exciting science. The deep sea
has provided many examples, but one stands out: the
effect of whale falls on the deep-sea bed. Large food
falls entering the deep sea initially provide a food
focus for scavengers; but it is now realized that the
food fall and the scavengers structure the seabed and
cause a variation in the local fauna. Subsequently,
Smith et al. (1989) showed that the whale skeleton
became a cold seep, and there was the suggestion that
such whale falls may be the stepping stones for the
dispersal of hydrothermal-vent faunas. Thus, a feature
that appeared originally to have a short time-scale is
now known to structure the deep-sea community over
a period of decades.
A tool that is fast becoming an essential part of
the armoury of the deep-sea biologist is molecular
technology. The use of molecular techniques in deepsea research has been pioneered particularly by those
working at hydrothermal vents (Vrijenhoek, 1997); but
the technology has massive applications in all aspects
of deep-sea biology, particularly inter alia in the field of
population biology, the identification of cryptic species
(Etter et al., 1999), and the analysis of experimental
studies on the invasion of the deep sea (Tyler and
Young, 1998).
EXPLOITATION
The deep sea is one of the least exploited environments
on earth. Challenges to it in terms of harvesting natural
resources or disposing of anthropogenic waste have
been essentially minimal, owing to the huge assimilative capacity of the ocean. However, the deep sea is now
being seen much more to contain harvestable resources.
Oil exploration is moving into deeper and deeper water.
It should, however, be noted that most exploration oil
companies have a positive environmental attitude to
the deep sea and will not exploit if there is likely
to be an environmental penalty. Of more concern is
fishing activity as it moves into deeper water. Already
the populations of orange roughy (Hoplostethus atlanticus) have declined disastrously before any useful
management strategy could be put in place. Is there
enough productivity along the continental margins to
sustain a profitable fishing industry without the overexploitation seen in many shelf fisheries in the North
Atlantic? Fishing at bathyal depths in the northeast
Atlantic is both actively and passively resulting in
the destruction of colonies of the deep-water coral
Lophelia pertusa and of the large hexactinellid sponges
that are found on soft sediments and rock. Remarkably
little is known about these magnificent organisms
or the associated faunas. Such knowledge should be
gained before exploitation continues. These are specific
challenges for the deep-sea biologist.
Disposal in the deep sea is nowhere near the scale on
which it has occurred in coastal waters. Environmental
legislation is resulting in the clean-up of coastal waters,
and may limit any disposal in the deep sea. Since the
1980s, official action has been taken to limit waste
disposal in the deep sea; previously it was more or less
unrestricted (see Chapter 13). Subsequently, there has
475
from a surface ship. This technology has developed
rapidly over the last ten years, and is used extensively –
for instance, to study scavenging by deep-sea crustacea
and fish, or to measure temporal variables such as the
oxygen consumption of the sediment community (see
Chapter 11). The use of landers will continue to provide
a valuable platform for deep-sea experimentation.
Possibly the greatest advance for deep-sea experimental biology has been the development of the
manned submersible. In its traditional form this is a
vehicle that will take pilots and observers to the deepsea bed, where they can conduct in situ experiments
as well as making observations. Even more recent
is the development of Remote Operated Vehicles in
which the vehicle is operated by a pilot and observer
on the mother vessel, obviating the potential dangers
of subjecting them to pressures of several hundred
atmospheres in the ocean. ROVs have developed so far
in the last five years that they have almost the same
capability as manned submersibles. Last of the new
batch of engineering technologies is the ‘Autonomous
Underwater Vehicle’, which is able inter alia to map
and photograph the seafloor. Such vehicles may well
herald a new era of deep-sea exploration.
Submersibles have been critical to the success of
observation and experimentation at hydrothermal vents.
Without the ability to work at a scale of less than
one metre, considerably less would have been achieved
at hydrothermal vents. The physiology of the unique
organisms at vents is now well understood (Van Dover,
2000), while the microenvironment (Luther et al., 2001)
and the most intractable of processes, dispersal, are
now being unravelled (Marsh et al., 2001; Pradillon
et al., 2001). Vents are even known to emit light (White
et al., 2000), leading to speculation on the origins of
photosynthesis, and even life itself.
It is always possible to plan and execute experiments,
but it is often the serendipitous observation that leads
to some of the most exciting science. The deep sea
has provided many examples, but one stands out: the
effect of whale falls on the deep-sea bed. Large food
falls entering the deep sea initially provide a food
focus for scavengers; but it is now realized that the
food fall and the scavengers structure the seabed and
cause a variation in the local fauna. Subsequently,
Smith et al. (1989) showed that the whale skeleton
became a cold seep, and there was the suggestion that
such whale falls may be the stepping stones for the
dispersal of hydrothermal-vent faunas. Thus, a feature
that appeared originally to have a short time-scale is
now known to structure the deep-sea community over
a period of decades.
A tool that is fast becoming an essential part of
the armoury of the deep-sea biologist is molecular
technology. The use of molecular techniques in deepsea research has been pioneered particularly by those
working at hydrothermal vents (Vrijenhoek, 1997); but
the technology has massive applications in all aspects
of deep-sea biology, particularly inter alia in the field of
population biology, the identification of cryptic species
(Etter et al., 1999), and the analysis of experimental
studies on the invasion of the deep sea (Tyler and
Young, 1998).
EXPLOITATION
The deep sea is one of the least exploited environments
on earth. Challenges to it in terms of harvesting natural
resources or disposing of anthropogenic waste have
been essentially minimal, owing to the huge assimilative capacity of the ocean. However, the deep sea is now
being seen much more to contain harvestable resources.
Oil exploration is moving into deeper and deeper water.
It should, however, be noted that most exploration oil
companies have a positive environmental attitude to
the deep sea and will not exploit if there is likely
to be an environmental penalty. Of more concern is
fishing activity as it moves into deeper water. Already
the populations of orange roughy (Hoplostethus atlanticus) have declined disastrously before any useful
management strategy could be put in place. Is there
enough productivity along the continental margins to
sustain a profitable fishing industry without the overexploitation seen in many shelf fisheries in the North
Atlantic? Fishing at bathyal depths in the northeast
Atlantic is both actively and passively resulting in
the destruction of colonies of the deep-water coral
Lophelia pertusa and of the large hexactinellid sponges
that are found on soft sediments and rock. Remarkably
little is known about these magnificent organisms
or the associated faunas. Such knowledge should be
gained before exploitation continues. These are specific
challenges for the deep-sea biologist.
Disposal in the deep sea is nowhere near the scale on
which it has occurred in coastal waters. Environmental
legislation is resulting in the clean-up of coastal waters,
and may limit any disposal in the deep sea. Since the
1980s, official action has been taken to limit waste
disposal in the deep sea; previously it was more or less
unrestricted (see Chapter 13). Subsequently, there has