Ecophysiology of the marine cyanobacterium, Lyngbya majuscula (Oscillatoriaceae) in Moreton Bay, Australia

Watkinson, AJ, ONeil, JM and Dennison, WC (2005) Ecophysiology of the marine cyanobacterium, Lyngbya majuscula (Oscillatoriaceae) in Moreton Bay, Australia. Harmful Algae, 4 4: 697-715. doi:10.1016/j.hal.2004.09.001

Author Watkinson, AJ
ONeil, JM
Dennison, WC
Title Ecophysiology of the marine cyanobacterium, Lyngbya majuscula (Oscillatoriaceae) in Moreton Bay, Australia
Journal name Harmful Algae   Check publisher's open access policy
ISSN 1568-9883
Publication date 2005-01-01
Sub-type Article (original research)
DOI 10.1016/j.hal.2004.09.001
Volume 4
Issue 4
Start page 697
End page 715
Total pages 19
Editor S.E. Shumway
T. Smayda
Place of publication Netherlands
Publisher Elsevier
Language eng
Subject C1
270702 Marine and Estuarine Ecology (incl. Marine Ichthyology)
770399 Other
Abstract Large blooms of the marine cyanobacterium Lyngbya majuscula in Moreton Bay, Australia (27 degrees 05'S, 153 degrees 08'E) have been re-occurring for several years. A bloom was studied in Deception Bay (Northern Moreton Bay) in detail over the period January-March 2000. In situ data loggers and field sampling characterised various environmental parameters before and during the L. majuscula bloom. Various ecophysiological experiments were conducted on L. majuscula collected in the field and transported to the laboratory, including short-term (2h) C-14 incorporation rates and long-term (7 days) pulse amplitude modulated (PAM) fluorometry assessments of photosynthetic capacity. The effects of L. majuscula on various seagrasses in the bloom region were also assessed with repeated biomass sampling. The bloom commenced in January 2000 following usual December rainfall events, water temperatures in excess of 24 degrees C and high light conditions. This bloom expanded rapidly from 0 to a maximum extent of 8 km(2) over 55 days with an average biomass of 210 g(dw)(-1) m(-2) in late February, followed by a rapid decline in early April. Seagrass biomass, especially Syringodium isoetifolium, was found to decline in areas of dense L. majuscula accumulation. Dissolved and total nutrient concentrations did not differ significantly (P > 0.05) preceding or during the bloom. However, water samples from creeks discharging into the study region indicated elevated concentrations of total iron (2.7-80.6 mu M) and dissolved organic carbon (2.5-24.7 mg L-1), associated with low pH values (3.8-6.7). C-14 incorporation rates by L. majuscula were significantly (P < 0.05) elevated by additions of iron (5 mu M Fe), an organic chelator, ethylenediaminetetra-acetic acid (5 mu M EDTA) and phosphorus (5 mu M PO4-3). Photosynthetic capacity measured with PAM fluorometry was also stimulated by various nutrient additions, but not significantly (P > 0.05). These results suggest that the L. majuscula bloom may have been stimulated by bioavailable iron, perhaps complexed by dissolved organic carbon. The rapid bloom expansion observed may then have been sustained by additional inputs of nutrients (N and P) and iron through sediment efflux, stimulated by redox changes due to decomposing L. majuscula mats. (c) 2004 Elsevier B.V. All rights reserved.
Keyword Marine & Freshwater Biology
Lyngbya Majuscula
Moreton Bay
C-14 Incorporation
Pam Fluorometry
Natural Organic-matter
Nutrient Concentrations
Primary Productivity
Estuarine Gradient
N-2 Fixation
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2006 Higher Education Research Data Collection
National Research Centre for Environmental Toxicology Publications
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Created: Wed, 15 Aug 2007, 15:21:44 EST