32
P. Tett
amount of phytoplankton compared with the period 1970–1976, because of the
additional nutrient input by the salmon farm now present in the loch. Instead, we
found a decrease in average concentrations of chlorophyll (Laurent et al. 2006).
The cause of this has yet to be explained. Are farmed mussels eating more phytoplankton? Is the loch chemically polluted by antifouling compounds? Are new
chemicals in use on land surrounding the loch? Have its waters become more turbid? The WFD calls for investigative monitoring where:
surveillance monitoring indicates that the objectives set out in Article 4 for a body of water
are not likely to be achieved and operational monitoring has not already been established,
in order to ascertain the causes of a water body or water bodies failing to achieve the
environmental objectives.
However, since the emphasis by the WFD, as shown in Table 1.3, is on accelerated
growth of algae, it is not clear that there is a failure to achieve the Directive’s objectives. The question may turn on whether there has been an undesirable disturbance
to the balance of organisms, which takes us to the topic of ecosystem health.
1.12 Ecosystem Health
The WFD’s type specific reference conditions can be interpreted to imply that there
is, or was, an ideal, “natural”, or “pristine” state, and that any change from this state
is a deterioration. But there is a practical problem in identifying reference conditions, given that high status corresponds to a state in which
no, or only very minor, anthropogenic alterations to the values of the physico-chemical and
hydromorphological quality elements… from those normally associated with that type
under undisturbed conditions. The values of the biological quality elements… reflect those
normally associated with that type under undisturbed conditions, and show no, or only
very minor, evidence of distortion.
The practical problem is that there are few sites in Europe that are completely free
of such disturbance and there is, indeed, some uncertainty about separating developing human influence from natural changes since the ending of the last glaciation.
Given that it is unfeasible to seek completely pristine conditions, a realistic aim
might be to describe the way things might have been before the industrial revolution in the 19th century. This is exemplified by a modeling study of nutrient discharge from the river Seine, and its effects on the trophic status of the Seine estuary
(Cugier et al. 2005).
I think of this interpretation of WFD as seeking a return to a past Eden or golden
age, or at least a tolerable approximation thereto. But we live in the here and now,
and it may be better to seek a definition of reference conditions that takes account
of this. So let us consider the alternative idea that the ideal state for an ecosystem
is that of good health, irrespective of whether this state is natural or the result of
human management. According to Costanza (1992), a healthy ecosystem, like a
healthy human body, is a system that functions well and is able to resist or recover
P. Tett
amount of phytoplankton compared with the period 1970–1976, because of the
additional nutrient input by the salmon farm now present in the loch. Instead, we
found a decrease in average concentrations of chlorophyll (Laurent et al. 2006).
The cause of this has yet to be explained. Are farmed mussels eating more phytoplankton? Is the loch chemically polluted by antifouling compounds? Are new
chemicals in use on land surrounding the loch? Have its waters become more turbid? The WFD calls for investigative monitoring where:
surveillance monitoring indicates that the objectives set out in Article 4 for a body of water
are not likely to be achieved and operational monitoring has not already been established,
in order to ascertain the causes of a water body or water bodies failing to achieve the
environmental objectives.
However, since the emphasis by the WFD, as shown in Table 1.3, is on accelerated
growth of algae, it is not clear that there is a failure to achieve the Directive’s objectives. The question may turn on whether there has been an undesirable disturbance
to the balance of organisms, which takes us to the topic of ecosystem health.
1.12 Ecosystem Health
The WFD’s type specific reference conditions can be interpreted to imply that there
is, or was, an ideal, “natural”, or “pristine” state, and that any change from this state
is a deterioration. But there is a practical problem in identifying reference conditions, given that high status corresponds to a state in which
no, or only very minor, anthropogenic alterations to the values of the physico-chemical and
hydromorphological quality elements… from those normally associated with that type
under undisturbed conditions. The values of the biological quality elements… reflect those
normally associated with that type under undisturbed conditions, and show no, or only
very minor, evidence of distortion.
The practical problem is that there are few sites in Europe that are completely free
of such disturbance and there is, indeed, some uncertainty about separating developing human influence from natural changes since the ending of the last glaciation.
Given that it is unfeasible to seek completely pristine conditions, a realistic aim
might be to describe the way things might have been before the industrial revolution in the 19th century. This is exemplified by a modeling study of nutrient discharge from the river Seine, and its effects on the trophic status of the Seine estuary
(Cugier et al. 2005).
I think of this interpretation of WFD as seeking a return to a past Eden or golden
age, or at least a tolerable approximation thereto. But we live in the here and now,
and it may be better to seek a definition of reference conditions that takes account
of this. So let us consider the alternative idea that the ideal state for an ecosystem
is that of good health, irrespective of whether this state is natural or the result of
human management. According to Costanza (1992), a healthy ecosystem, like a
healthy human body, is a system that functions well and is able to resist or recover