Influence of macronutrient and iron enrichment on phytoplankton productivity and community dynamics: an in situ microcosm study in a drinking water supply reservoir

Luong, HA; Rohlfs, AM; Facey, JA; Colville, A; Davie, AW; Pera, JB; Mitrovic, SM

Influence of macronutrient and iron enrichment on phytoplankton productivity and community dynamics: an in situ microcosm study in a drinking water supply reservoir

Luong, HA Rohlfs, AM Facey, JA Colville, A Davie, AW Pera, JB Mitrovic, SM

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Publisher:: TAYLOR & FRANCIS LTD
Publication Type:: Journal Article
Citation:: Inland Waters, 2025, 15, (1)
Issue Date:: 2025-01-01

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Field	Value	Language
dc.contributor.author	Luong, HA
dc.contributor.author	Rohlfs, AM
dc.contributor.author	Facey, JA
dc.contributor.author	Colville, A
dc.contributor.author	Davie, AW
dc.contributor.author	Pera, JB
dc.contributor.author	Mitrovic, SM
dc.date.accessioned	2025-08-06T04:15:58Z
dc.date.available	2025-08-06T04:15:58Z
dc.date.issued	2025-01-01
dc.identifier.citation	Inland Waters, 2025, 15, (1)
dc.identifier.issn	2044-2041
dc.identifier.issn	2044-205X
dc.identifier.uri	http://hdl.handle.net/10453/189203
dc.description.abstract	This study examines the influence of macronutrients (nitrogen and phosphorus) and trace metals (iron and manganese) on phytoplankton productivity and community composition in Prospect Reservoir, a key component of the drinking water supply for Greater Sydney, Australia. In situ microcosm bioassays were set up at 2 sites (shallow and pelagic) during the Austral growing season (early autumn), and the responses of phytoplankton to various nutrient enrichment scenarios were assessed following an 8-day incubation period. Initial conditions and nutrient additions were compared by analyzing productivity indicators including chlorophyll a (Chl-a), total phytoplankton, and potentially toxic cyanobacteria biovolume. Phytoplankton community changes were identified using functional group classification and hierarchical cluster analysis. Productivity was colimited by nitrogen and phosphorus. Addition of these nutrients was associated with significant growth and dominance of group F, representing green algae such as Scenedesmus and Oocystis. Significant growth was also observed in meso-eutrophic groups that included the nuisance cyanobacteria Microcystis (M). An additional enhancement in Chl-a and phytoplankton biovolume in the pelagic site was observed when iron was added. Group D, represented by the nuisance taxon Synedra, seemed to dominate in low-P conditions. The study highlights the importance of informed eutrophication management strategies that address nutrient dynamics including macronutrient colimitation, macronutrient ratios, and iron to mitigate the risks associated with increased phytoplankton productivity and nuisance phytoplankton growth in drinking water reservoirs. This knowledge is particularly significant given the projected increase in macronutrient and trace metal micronutrient inputs and climate change-driven events such as bush fires and flooding.
dc.language	English
dc.publisher	TAYLOR & FRANCIS LTD
dc.relation.ispartof	Inland Waters
dc.relation.isbasedon	10.1080/20442041.2025.2475662
dc.rights	info:eu-repo/semantics/openAccess
dc.subject	0406 Physical Geography and Environmental Geoscience, 0502 Environmental Science and Management, 0602 Ecology
dc.subject.classification	3103 Ecology
dc.subject.classification	4104 Environmental management
dc.title	Influence of macronutrient and iron enrichment on phytoplankton productivity and community dynamics: an in situ microcosm study in a drinking water supply reservoir
dc.type	Journal Article
utslib.citation.volume	15
utslib.for	0406 Physical Geography and Environmental Geoscience
utslib.for	0502 Environmental Science and Management
utslib.for	0602 Ecology
pubs.organisational-group	University of Technology Sydney
pubs.organisational-group	University of Technology Sydney/Faculty of Science
pubs.organisational-group	University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	open_access	*
dc.rights.license	This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-nd/4.0/
dc.date.updated	2025-08-06T04:15:55Z
pubs.issue	1
pubs.publication-status	Published
pubs.volume	15
utslib.citation.issue	1

Abstract:

This study examines the influence of macronutrients (nitrogen and phosphorus) and trace metals (iron and manganese) on phytoplankton productivity and community composition in Prospect Reservoir, a key component of the drinking water supply for Greater Sydney, Australia. In situ microcosm bioassays were set up at 2 sites (shallow and pelagic) during the Austral growing season (early autumn), and the responses of phytoplankton to various nutrient enrichment scenarios were assessed following an 8-day incubation period. Initial conditions and nutrient additions were compared by analyzing productivity indicators including chlorophyll a (Chl-a), total phytoplankton, and potentially toxic cyanobacteria biovolume. Phytoplankton community changes were identified using functional group classification and hierarchical cluster analysis. Productivity was colimited by nitrogen and phosphorus. Addition of these nutrients was associated with significant growth and dominance of group F, representing green algae such as Scenedesmus and Oocystis. Significant growth was also observed in meso-eutrophic groups that included the nuisance cyanobacteria Microcystis (M). An additional enhancement in Chl-a and phytoplankton biovolume in the pelagic site was observed when iron was added. Group D, represented by the nuisance taxon Synedra, seemed to dominate in low-P conditions. The study highlights the importance of informed eutrophication management strategies that address nutrient dynamics including macronutrient colimitation, macronutrient ratios, and iron to mitigate the risks associated with increased phytoplankton productivity and nuisance phytoplankton growth in drinking water reservoirs. This knowledge is particularly significant given the projected increase in macronutrient and trace metal micronutrient inputs and climate change-driven events such as bush fires and flooding.

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http://hdl.handle.net/10453/189203