Chlorophyll a

Indicator summary

Summary of indicator structure and function

Examples of how the indicators is used for ecosystem management and ecosystem status and trends

Definition and/or background

The following is from Fulton et al 2004a -

Chlorophyll a (as an easily measurable index of phytoplankton) is already widely used in monitoring the effects of eutrophication (Harris et al. 1996) and is increasingly the subject of correlative studies with fisheries production (e.g. Parsons and Chen 1994). It has a lot of potential as an ecological indicator of the effects of fishing. This is not only because in conjunction with other measures (e.g. size-spectra) it can indicate whether or not fishing is the cause of any changes seen, but in its own right it can highlight the effects of fishing where these impact upon productivity or the trophic structure of the ecosystem. For example, it has been shown (Frid et al. 2000) that the disturbance of the sediment by fishing can modify the remineralisation of organic matter, which in turn effects the nutrient availability in the overlying water column and this effects the phytoplankton (and thus chlorophyll a). The widespread use of this indicator in other fields, mean that there is a large body of literature to build from and that reference points and relationships between chlorophyll a and nutrient levels (e.g. Monbet 1992) are already well known.

Attribute

Tropic structure, community structure, eutrophication

Purpose

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Taxa

As appropriate list an taxa that this indicator is restricted to

Data required

The following is from Fulton et al 2004a -

• Concentration of chlorophyll a

Ecosystem applicability

The following is from Fulton et al 2004a -

Should be applicable in all ecosystems.

Identified capability

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Biological classification level

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Response variable

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Drivers

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Robustness

The following is from Fulton et al 2004a -

Medium: by itself chlorophyll a is probably not a reliable indicator of the effects of fishing, but in conjunction with other indicators (e.g. size-spectra) it could be a very powerful summary indicator that not only identifies change, but helps to identify the cause of the change. However, even though it is widely used in other fields (e.g. water quality management) its role as an indicator for fisheries remains under tested.

Current status and trends

What was it like in an undisturbed/unexploited system?

How would it be expected to change?

Which way is the indicator showing a population is going in? decreasing or increasing?

Management objective/direction

Using the standard set of management objectives from Indiseas
* Conservations biodiversity
* Ecosystem stability and resistance to perturbations
* Ecosystem structure and functioning
* Resource potential

Has it been used in a management strategy? if so how?

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Stakeholder/Public acceptability

Acceptability with stakeholders?
* by all stakeholder
* by the public
* understandable to the stakeholders

References

Fulton, E.A., Smith, A.D.M., Webb, H., and Slater, J. (2004a) Ecological indicators for the impacts of fishing on non-target species, communities and ecosystems: Review of potential indicators. AFMA Final Research Report, report Number R99/1546.

References that Fulton et al uses for this indicator:

Frid, C. L. J., K. G. Harwood, S. J. Hall, and J. A. Hall. 2000. Long-term changes in the benthic communities on North Sea fishing grounds. ICES Journal of Marine Science 57: pp 1302-9.

Harris, G., G. Batley, P. Jernakoff, B. Newell, D. Fox, R. Molloy, J. Parslow, S. Walker, D. Hall, A. Murray, and G. Skyring. 1996. Port Phillip Bay environmental study: final report, CSIRO, Dickson, A.C.T..

Monbet, Y. 1992. Control of phytoplankton biomass in estuaries: a comparative analysis of microtidal and macrotidal estuaries. Estuaries 15, no. 4: pp 563-71.

Parsons, T. R., and Y.-L. L. Chen. 1994. Estimates of trophic efficiency, based on the size distribution of phytoplankton and fish in different environments. Zoological Studies 33, no. 4: pp 296-301.

Background reading

Fulton, E.A., Fuller,M., Smith, A.D.M., and Punt, A. (2004) Ecological indicators of the ecosystem effects of fishing: Final report. AFMA Final Research Report, report Number R99/1546.

Other references that can be used to update this page

Other references that SD has found that would be useful to update the indicator referred to on this page.

Citation

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Page created by:Shavawn Donoghue

Last modified on: Sep 05, 2012 16:16

Versions: 6, 5, 4, 3, 2, 1

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