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dc.contributor.authorPaul, Wendy J.
dc.contributor.authorHamilton, David P.
dc.contributor.authorGibbs, Max M.
dc.date.accessioned2009-08-02T23:42:57Z
dc.date.available2009-08-02T23:42:57Z
dc.date.issued2008
dc.identifier.citationGibbs, M. M., Hamilton, D. P. & Paul, W. J. (2008). Low-dose alum application trialled as a management tool for internal nutrient loads in Lake Okaro, New Zealand. New Zealand Journal of Marine and Freshwater Research, 42, 207- 217.en
dc.identifier.urihttps://hdl.handle.net/10289/2725
dc.description.abstractAluminium sulfate (alum) was applied to Lake Okaro, a eutrophic New Zealand lake with recurrent cyanobacterial blooms, to evaluate its suitability for reducing trophic status and bloom frequency. The dose yielded 0.6 g aluminium m–3 in the epilimnion. Before dosing, pH exceeded 8 in epilimnetic waters but was optimal for flocculation (6–8) below 4 m depth. After dosing, there was no significant change in water clarity, hypolimnetic pH decreased to 5.5, and soluble aluminium exceeded recommended guidelines for protection of freshwater organisms. Epilimnetic phosphate concentrations decreased from 40 to 5 mg m–3 and total nitrogen (TN):total phosphorus (TP) mass ratios increased from 7:1 to 37:1. The dominant phytoplankton species changed from Anabaena spp. before dosing, to Ceratium hirudinella , then Staurastrum sp. after dosing. Detection of effectiveness of dosing may have been limited by sampling duration and design, as well as the low alum dose. The decrease in hypolimnetic pH and epilimnetic TP, and increase in Al3+ and chlorophyll a, are attributed to the low alkalinity lake water and coincidence of alum dosing with a cyanobacterial bloom and high pH.en
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherRSNZ Publishingen_NZ
dc.relation.urihttp://www.royalsociety.org.nz/Site/publish/Journals/nzjmfr/2008/018.aspxen
dc.rightsThis article has been published in the New Zealand Journal of Marine and Freshwater Research. © The Royal Society of New Zealand 2008.
dc.subjectflocculationen
dc.subjectalkalinityen
dc.subjectanabaenaen
dc.subjectceratiumen
dc.subjecthirudinellaen
dc.subjectphosphorusen
dc.titleLow-dose alum application trialled as a management tool for internal nutrient loads in Lake Okaro, New Zealanden
dc.typeJournal Articleen
dc.identifier.doi10.1080/00288330809509949en_NZ
dc.relation.isPartOfNew Zealand Journal of Marine and Freshwater Researchen_NZ
pubs.begin-page207en_NZ
pubs.elements-id33529
pubs.end-page217en_NZ
pubs.issue2en_NZ
pubs.volume42en_NZ


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