Land based sources of pollution//source estimates

[Bob Buddemeier]

Katharina, or anyone --

Do you have either estimates or expert-judgement opinions on the relative extent
to which (or the geographic areas in which) the observed high-turbidity areas
are primarily related to:
a. medium or large river discharge;
b. stream, small river or open coast runoff; or
c. local resuspension of existing sediments?

Getting some idea of the relative importance of these components of the
turbidity forcing is critical to deriving impact predictions from climate, wave,
and land-use models.

Thanks,

Bob Buddemeier

Katharina Fabricius wrote:

> Another, recently published study from the Indo-Pacific province, in which
> we looked at the effects of increasing turbidity on biodiversity:
>
> Fabricius KE & De'ath G (2001) Biodiversity on the Great Barrier Reef:
> Large-scale patterns and turbidity-related local loss of soft coral taxa.
> Pp 127 - 144 in: Wolanski E (ed) Oceanographic processes of coral reefs:
> physical and biological links in the Great Barrier Reef. CRC Press, London.
>
> The article is best to be read in the original book which contains a CD
> with the colour images and animations of processes. In our chapter, we
> present a spatial model of increasing turbidtiy (originating from a
> single-point-discharge), related to decreasing biodiversity. However I'm
> happy to send out free reprints in paper form (black & white print) or
> electronically (colour).
>
> Abstract:
> Spatial patterns and abiotic controls of soft coral biodiversity were
> determined from an extensive reef surveys on the Great Barrier Reef (GBR).
> Taxonomic inventories of soft corals, and estimates of cover of the major
> benthos forms and of the physical environment, were obtained from 161
> reefs, spread relatively evenly along and across the whole GBR. Reefs on
> the mid-shelf between latitude 13° and 16° represented the "hotspot" of
> taxonomic richness in soft corals on the GBR. Overlapping distributions of
> in-shore and off-shore taxa maximised richness on mid-shelf reefs.
> Taxonomic richness decreased with increasing latitude, and was low and
> relatively even across the shelf south of 21° lat. Soft coral richness was
> strongly depressed in areas of high turbidity. It was also weakly
> positively related to the amount of sediment deposited, and strongly
> increased with depth. Total cover of hard corals and soft corals was poorly
> explained by physical and spatial variables, however both varied with depth.
> The findings presented here have three major management implications: (1)
> Turbidity and sedimentation affect the generic richness of soft corals.
> Reefs with highest soft coral richness are < 20 km from the coast, well
> within the range of terrestrial run-off, and hence a loss of biodiversity
> could result if turbidity increases due to land use practices which
> generate soil loss; (2) Taxonomic composition is more strongly related to
> environmental conditions than total hard and soft coral cover. Taxonomic
> inventories are thus better indicators of environmental conditions and
> human impacts than are assessments of total cover. (3) Richness and cover
> change more within a single site between 0 and 18 m depth, than between
> reefs hundreds of kilometers apart along the shelf at the same depth.
> Valuable additional information can be gained in a cost-efficient way if
> monitoring and survey programs covered several depth zones rather than a
> single depth.
>
> Regards,
>
> Katharina Fabricius
>
> <//\\><+><\\//><+><//\\><+><\\//><+><//\\><+><\\//>
>
> Dr. Katharina Fabricius
> Research Scientist
> Australian Institute of Marine Science
> PMB 3, Townsville Qld 4810, Australia
>
> Fax     +61 - 7 - 4772 5852
> Phone   +61 - 7 - 4753 4412  or 4758 1979
> email k.fabricius at email.aims.gov.au
>
> http://www.aims.gov.au
> http://www.reef.crc.org.au
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--
Dr. Robert W. Buddemeier
Kansas Geological Survey
University of Kansas
1930 Constant Avenue
Lawrence, KS 66047 USA
Ph (1) (785) 864-2112
Fax (1) (785) 864-5317
e-mail:  buddrw at kgs.ukans.edu


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