Some chemical factors regulating the growth of Lyngbya majuscula in Moreton Bay, Australia: importance of sewage discharges

Bell, PRF and Elmetri, I (2007) Some chemical factors regulating the growth of Lyngbya majuscula in Moreton Bay, Australia: importance of sewage discharges. Hydrobiologia, 592 1: 359-371. doi:10.1007/s10750-007-0773-8


Author Bell, PRF
Elmetri, I
Title Some chemical factors regulating the growth of Lyngbya majuscula in Moreton Bay, Australia: importance of sewage discharges
Journal name Hydrobiologia   Check publisher's open access policy
ISSN 0018-8158
Publication date 2007-01-01
Sub-type Article (original research)
DOI 10.1007/s10750-007-0773-8
Open Access Status DOI
Volume 592
Issue 1
Start page 359
End page 371
Total pages 13
Place of publication Dordrecht
Publisher Springer
Language eng
Abstract The relative importance of the additions of iron (Fe), phosphorus (P) and the chelating agent EDTA in promoting the growth of Lyngbya majuscula in waters collected from the NW region of Moreton Bay was investigated using a series of continuous-flow growth studies. In addition, the possible impact of sewage/waste-water treatment plant (WWTP) discharges on the growth of L. majuscula was investigated in a series of batch and semi-continuous-flow growth studies. A preliminary study on the potential of phytoplankton growth in the receiving waters to affect the productivity of L. majuscula was also conducted. The results from the continuous-flow growth studies show that the growth rates of L. majuscula in the NW Moreton Bay waters were stimulated by the addition of EDTA alone but were not stimulated by the addition of P. The additions of P + EDTA, FeEDTA and P + FeEDTA did not result in higher growth rates than those obtained by the addition of EDTA alone. These results demonstrate that the productivity of L. majuscula in the NW Moreton Bay waters was not limited by P and that the addition of Fe did not affect the productivity. The stimulation effect of EDTA could be due to various reasons but we hypothesise that the principal reason for the stimulation is that EDTA increases the bioavailability of non-labile Fe species already present in the water. The results of the batch and semi- continuous-flow growth studies show that diluted (100:1) WWTP discharge water and the receiving waters impacted by WWTP discharges supported significant growth of L. majuscula and that the addition of EDTA to those waters increased the growth potential of L. majuscula. Also the growth of phytoplankton in a sample of the receiving waters impacted by WWTP discharges significantly reduced the growth rate of L. majuscula but the addition of EDTA restored the growth rate to near its maximum value. These results suggest that phytoplankton growth (and probably that of the associated bacterioplankton) could reduce the bioavailability of trace chemical factors needed for the growth of L. majuscula in Moreton Bay and in particular, could reduce the bioavailability of Fe. Overall the results support the hypothesis that growth of L. majuscula in Moreton Bay is often limited by the bioavailability of Fe and the principal reason for this is the lack of supply of suitable organic ligands/chelators, not the lack of Fe per se.
Keyword Marine & Freshwater Biology
Lyngbya majuscula
EDTA
iron
chelation
sewage discharges
Marine-phytoplankton
Nitrogen-fixation
Trichodesmium Spp.
Iron Limitation
Oceanic Waters
Edta
Cyanobacteria
Rates
Populations
Speciation
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Journal Article Import (ISI/CVs)
 
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Created: Tue, 19 Feb 2008, 00:56:31 EST