Physical properties of the Great Barrier reef Lagoon waters near Townsville. II. Seasonal variations

1981 ◽  
Vol 32 (3) ◽  
pp. 321 ◽  
Author(s):  
E Wolanski ◽  
M Jones ◽  
WT Williams

The distribution of salinity, temperature, suspended particles, light transmissivity, chlorophyll a and phaeopigments across the Great Barrier Reef lagoon offshore Townsville, was measured from 9 January 1979 to 23 January 1980 at approximately weekly intervals. Previous observations at Low Isles. 400 km to the north, on seasonal variations of temperature and salinity were generally applicable here. A shallow summer thermocline was frequently observed in offshore waters, in the dry season and in calm weather. As a result of evaporation from the lagoon and adjoining mangrove swamps during the dry season, an inverse estuarine circulation can exist when high salinity, sediment-rich, nearshore waters sink below the less saline offshore waters. Only nearshore were bottom sediments strongly entrained in the water column during strong winds, principally in winter.

1982 ◽  
Vol 33 (4) ◽  
pp. 717 ◽  
Author(s):  
TA Walker

The occurrence of an evaporation-driven circulation in the Great Barrier Reef lagoon has recently been proposed. When the data on which the proposal is based are examined, together with further oceanographic and meteorological records for the same time period, it can be shown that the observed salinity structure resulted from advection of runoff-diluted water from the north. It is concluded that there is currently no evidence to support the existence of evaporation-driven circulation, and the probability of occurrence of such a process is low.


1981 ◽  
Vol 32 (3) ◽  
pp. 305 ◽  
Author(s):  
E Wolanski ◽  
M Jones

Floods from land runoff, principally the Burdekin River. created buoyant freshwater plumes along the coast of the Great Barrier Reef lagoon. From Cape Upstart near the Burdekin River mouth to Innisfail 250 km north. no evidence was found of these plumes directly reaching the Great Barrier Reef. Small buoyant patches, detached from the river plumes, found further offshore might reach the Great Barrier Reef. Classical estuarine circulation in the lagoon. even in flood conditions, and tidal flushing by the ocean do not appear to be significant compared to advective processes.


1986 ◽  
Vol 37 (5) ◽  
pp. 545 ◽  
Author(s):  
GL Pickard

At Davies Reef, flow over the east reef flat was unidirectional downwind at 10-20 cm s-1 with strong winds and smaller tides but was semi-diurnal tidal reversing at 5-15 cm s-1 with lighter winds and higher tides. The flood direction was to the south-east out of the lagoon and the ebb into the lagoon. Wave overtopping was estimated to contribute at least 40% of the flow over the reef flat-the first estimate of this component of flow over reef flats. Transit times over the reef flat were 30-170 min and flushing times for the east lagoon were estimated as ½ -1 day for strong winds to the north-west but 2-4 days for lighter winds. In the east lagoon, the upper-layer currents were semi-diurnal tidal reversing all the time at speeds up to 20 cm s-1, with longer-term net flow downwind at about 2 cm s-1 with strong winds but upwind at 0.2 cm s-1 with light winds. In the east passage, the strongly tidal currents (up to 60 cm s-1.) had a long-term net flow to the south at about 2 cm s-1 without any clear correlation with the wind.


2012 ◽  
Vol 65 (4-9) ◽  
pp. 249-260 ◽  
Author(s):  
Britta Schaffelke ◽  
John Carleton ◽  
Michele Skuza ◽  
Irena Zagorskis ◽  
Miles J. Furnas

2021 ◽  
Vol 171 ◽  
pp. 112655
Author(s):  
G.L. McCloskey ◽  
R. Baheerathan ◽  
C. Dougall ◽  
R. Ellis ◽  
F.R. Bennett ◽  
...  

1990 ◽  
Vol 41 (3) ◽  
pp. 399 ◽  
Author(s):  
MCL Dredge

Movement, growth and natural mortality rate of the red spot king prawn, Penaeus longistylus, occurring in waters of the Great Barrier Reef off Townsville, Queensland, were investigated in a series of tagging experiments. Adult P. longistylus did not migrate after leaving nursery areas. Their growth rate was slower than that of the conspecific species P. plebejus, and significant inter-annual variation in growth parameters was observed. The natural mortality rate, assessed by sequential tagging experiments that eliminated the possibility of confounding with the rate of fishing mortality, was estimated to be 0.072 (week-1).


1956 ◽  
Vol 7 (3) ◽  
pp. 317 ◽  
Author(s):  
R Endean ◽  
W Stephenson ◽  
R Kenny

The species composition and general ecology of intertidal organisms present at Heron Island, a coral cay in the Capricorn Group, are recorded in this paper. It was found that the general zonation picture on this Great Barrier Reef island differed markedly from that found previously at localities on the Queensland mainland (Endean, Kenny, and Stephenson 1956). In particular the mainland upper barnacle (Chthamalus) zone was not represented at Heron I., and the species forming the mainland lower barnacle zone (Tetraclita squamosa (Bruguiere) ) was replaced by a different species (Tetraclita vitiata Darwin). Also the characteristic algal zone of mainland localities was replaced by a lithothamnion-zoanthid-coral zone. In order to investigate the possibility of a gradual transition from the mainland type zonation to that found on the Great Barrier Reef, as exemplified by Heron I. zonation, the species composition and general ecology of intertidal organisms inhabiting a series of continental islands lying off the Queensland coast between lat. 16� and 22� S. were investigated. The fauna of these islands was found to be closely allied to that of the mainland. There was, however, an intrusion of corals and zoanthids on the more exposed of the islands visited which lie between lat. 20� and 22�S., and also on the more northerly of the islands visited. The biogeographical implications of these findings are discussed, and it is noted that the results of the present investigation support the contention of Whitley (1932) that a longitudinal division of the Queensland marine fauna into "Solanderian" and "Banksian" elements is warranted. Accounts are also given of the major environmental factors that might affect specific composition and zonation patterns at the localities investigated. Analyses of these have given much information on the general ecology and distribution of many Queensland intertidal species. Thls information is discussed. Of particular interest was the finding that the Peronian barnacle Tetraclita rosea (Krauss) has extended its range,to the north of the biogeographical boundary situated near lat. 25� S. by colonizing the more exposed of the continental islands.


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