scholarly journals Effects of phosphorus on the growth and nitrogen fixation rates of Lyngbya majuscula: implications for management in Moreton Bay, Queensland

2004 ◽  
Vol 281 ◽  
pp. 27-35 ◽  
Author(s):  
I Elmetri ◽  
PRF Bell
Keyword(s):  
Nitrogen Fixation ◽  
Lyngbya Majuscula ◽  
Moreton Bay

Effects of Lyngbya majuscula (Cyanophycea) blooms on sediment nutrients and meiofaunal assemblages in seagrass beds in Moreton Bay, Australia

2006 ◽  
Vol 57 (2) ◽  
pp. 155 ◽  
Author(s):  
Rosa García ◽  
Ron W. Johnstone
Keyword(s):  
Depth Distribution ◽  
East Coast ◽  
Oxygen Depletion ◽  
Seagrass Beds ◽  
Biogeochemical Processes ◽  
Sediment Depth ◽  
Lyngbya Majuscula ◽  
Moreton Bay ◽  
Bloom Period ◽  
Abundance And Distribution

Blooms of Lyngbya majuscula have been increasingly recorded in the waters of Moreton Bay, on the south-east coast of Queensland, Australia. The influences of these blooms on sediment infauna and the implications for sediment biogeochemical processes was studied. Sediment samples were taken from Moreton Bay banks during and after the bloom season. The deposition of L. majuscula seems to be responsible for the higher total Kjedahl nitrogen (TKN) concentrations measured during the bloom period. Total organic carbon (TOC) concentrations did not change. Lyngbya majuscula blooms had a marked influence on the meiobenthos. Nematodes, copepods and polychaetes were the most abundant groups of meiofauna, and the bloom produced a decrease in the abundance and a change in the sediment depth distribution of these organisms. The distribution of nematodes, copepods and polychaetes in sediment became shallower. Further, the bloom did not affect the abundance and distribution of polychaetes as strongly as it did copepods and nematodes. The changes observed in the distribution of meiofauna in the sediment during the bloom period indicate that L. majuscula produces oxygen depletion in sediments, and that different fauna seem to be affected to different degrees.

Using Animal-Borne Imaging to Assess Green Turtle (Chelonia mydas) Foraging Ecology in Moreton Bay, Australia

2007 ◽  
Vol 41 (4) ◽  
pp. 9-13 ◽  
Author(s):  
Karen E. Arthur ◽  
Judith M. O'Neil ◽  
Colin J. Limpus ◽  
Kyler Abernathy ◽  
Greg Marshall
Keyword(s):  
Feeding Ecology ◽  
Green Turtle ◽  
Foraging Ecology ◽  
Chelonia Mydas ◽  
Lyngbya Majuscula ◽  
Imaging Device ◽  
Green Turtles ◽  
Moreton Bay ◽  
Turtle Population ◽  
Insight Into

Traditional techniques for studying green turtle foraging ecology, such as the analysis of food availability and ingested dietary material, have concluded that green turtles are primarily herbivorous but selective foragers. However, green turtles that forage during Lyngbya majuscula blooms are exposed to toxins produced by the cyanobacterium overgrowing the seagrass. We used the Crittercam, an animal-borne imaging device, to observe green turtle foraging behavior in Moreton Bay, Australia, and to evaluate the system for assessing the impacts of Lyngbya blooms on green turtles. Eight large green turtles were captured while foraging on seagrass flats and each was fitted with a Crittercam. The deployments yielded over 28 hours of video and associated time-depth records. Turtles swam almost continuously and rarely stopped to feed on seagrass. Six turtles were observed feeding and all six consumed gelatinous animals from the water column. This prey source was previously undocumented in the Moreton Bay green turtle population but described in other green turtle populations using the Crittercam. Only one turtle was observed foraging on seagrass. The results of this study indicate that Crittercam technology can provide insight into turtle diet selection and that it will be a useful tool in identifying the impacts of Lyngbya blooms on green turtle feeding ecology. This study has also demonstrated that turtles in Moreton Bay may have a more flexible diet than previously described, indicating they could potentially supplement their diet with alternate prey items when seagrass quality or quantity is compromised. Longer deployment times, with an initial acclimation phase, are required to more fully understand questions pertaining to feeding ecology.

Dermal toxicology of Lyngbya majuscula, from Moreton Bay, Queensland, Australia

Harmful Algae ◽  
2008 ◽  
Vol 7 (5) ◽  
pp. 584-589 ◽  
Author(s):  
Nick Osborne ◽  
Alan Seawright ◽  
Glen Shaw
Keyword(s):  
Lyngbya Majuscula ◽  
Moreton Bay

The potential of benthic iron and phosphorus fluxes to support the growth of a bloom forming toxic cyanobacterium Lyngbya majuscula, Moreton Bay, Australia

2016 ◽  
Vol 67 (12) ◽  
pp. 1918 ◽  
Author(s):  
Peter Hanington ◽  
Andrew Rose ◽  
Ron Johnstone
Keyword(s):  
Water Column ◽  
Benthic Community ◽  
Sediment Cores ◽  
Community Change ◽  
Flood Event ◽  
Nutrient Fluxes ◽  
Marine Cyanobacterium ◽  
Lyngbya Majuscula ◽  
Moreton Bay ◽  
Sandy Sediments

Lyngbya majuscula is a bloom-forming toxic marine cyanobacterium. Most research on L. majuscula growth in Moreton Bay has focussed on water column supplies of iron and phosphorus with little consideration of benthic sources and supply. This study investigates the potential for sandy sediments in a shallow, well mixed subtropical embayment (Deception Bay, Moreton Bay, Australia) to supply iron and phosphorus for L. majuscula growth after significant benthic community change following a major flood event. Measurements of benthic oxygen, iron and nutrient fluxes were obtained by incubating intact sediment cores sampled from Deception Bay. Results suggest that post-flood sediment communities are capable of supplying >1300% of daily L. majuscula Fe requirements and up to 9.2% of daily P demands, suggesting that L. majuscula growth in Deception Bay is likely to be P limited. The benthic release of PO43– and FeII only occurred after water column DO became depleted below 3mgL–1. This study suggests that the benthic release of PO43– and FeII could support the initiation and growth of L. majuscula blooms in Deception Bay.

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