Origins of water within warm-core eddies of the western Tasman Sea

1983 ◽  
Vol 34 (4) ◽  
pp. 525 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
High Salinity ◽  
East Australian Current ◽  
Surrounding Water ◽  
Warm Core ◽  
Tasman Sea ◽  
The Face

Comparison of the salinity within and around warm-core eddies of the western Tasman Sea has shown (a) that such eddies have their origin solely within waters of the East Australian Current (EAC); (b) that as these eddies drift southward within the EAC, their salinity characteristics differ little from those of the surrounding water; (c) that after separation from the EAC at around 34�S., their salinity characteristics are generally conserved in the face of much lower salinities of the surrounding waters. This latter feature was especially marked in the case of eddy J, which maintained in the upper 250 m an abnormally high salinity signature to as far south as 40� Below 300 m, this eddy J contained remnants of another high-salinity eddy. Possible derivations of these deeper waters are examined.

Some zooplankton characteristics of warm-core eddies shed by the East Australian Current, with particular reference to copepods

1983 ◽  
Vol 34 (4) ◽  
pp. 587 ◽  
Author(s):  
DJ Tranter ◽  
DJ Tafe ◽  
RL Sandland
Keyword(s):  
Free Fall ◽  
Dry Weight ◽  
Physical Structure ◽  
East Australian Current ◽  
The South ◽  
Warm Core ◽  
Tasman Sea

Several eddies in the south-western Tasman Sea were investigated to see whether they differed faunistically from the seas around them. Zooplankton samples (0-200 m) were taken by free-fall net for dry weight measurements and copepod analyses. The counts obtained for 20 species of copepod were used to classify 51 stations into (eight) groups. These were taken to constitute the major zooplankton habitats in the study area. These habitats corresponded in most respects with the known physical structure of the study area. Eddies were faunistically distinct from the seas that surrounded them. Eddy J was similar in 1979-1980 to the waters of the East Australian Current, which were periodically entrained within the eddy circulation. There were significant faunal differences between eddy J and eddy F, an isolated eddy sampled in December 1978.

Hydrological stucture and phytoplankton distribution in the region of a warm-core eddy in the Tasman Sea

1981 ◽  
Vol 32 (4) ◽  
pp. 479 ◽  
Author(s):  
BD Scott
Keyword(s):  
Phytoplankton Biomass ◽  
New South ◽  
Mesoscale Eddy ◽  
Surrounding Water ◽  
The Core ◽  
Phytoplankton Distribution ◽  
Warm Core ◽  
South Wales ◽  
Tasman Sea ◽  
Phosphate Silicate

The distribution of temperature, salinity, density, dissolved oxygen, phosphate, silicate, and nitrate to 2000 m depth, and phytoplankton to 150 m depth is described in the region of an anticyclonic mesoscale eddy located in the Tasman Sea. Vertical discontinuities in the hydrological properties showed that the eddy had entrained several surrounding water types at the surface and at depths of up to 500 m. In particular, Bass Strait water normally found among the slope waters along the New South Wales coast was entrained by the eddy and transported to positions 200 km from the coast. The temperature and salinity of the eddy appeared to have been increased below the core of the eddy at depths of 300-600 m. due to the entrainment of and mixing with Bass Strait water. The distribution of density, oxygen, nutrients and phytoplankton in the central portion of the eddy between 60 and 240 m depth showed differences between adjoining positions which were attributed to vertical water movements within the eddy core. These movements appeared to be responsible for increases of phytoplankton biomass within the eddy, of up to 10 times that of the surrounding ocean.

Physical evolution of Tasman Sea Eddy J

1983 ◽  
Vol 34 (4) ◽  
pp. 495 ◽  
Author(s):  
GR Cresswell
Keyword(s):  
Mixed Layer ◽  
East Australian Current ◽  
Surface Mixed Layer ◽  
Deep Surface ◽  
Warm Core ◽  
Tasman Sea ◽  
Observation Period ◽  
Subsequent Identification

The evolution of warm-core eddy J was followed from March 1979 until May 1980. From March to October 1979, eddy J developed a deep surface mixed layer that, after summer capping, became a subsurface 'signature' for subsequent identification. During the first half of the observation period, eddy J was subjected to frequent peripheral injections of northern water, mainly from the East Australian Current but on one occasion from a northern eddy. Between mid-December 1979 and early February 1980, the signature layer of eddy J moved on top of the signature layer of another eddy. This is suggested to be an indication of the coalescence of the two eddies. The prehistory of eddy J was conjectured from the nature of a signature layer that the eddy already had in March 1979.

Isothermal temperatures and transformations of the warm-core eddies in the western Tasman Sea

1983 ◽  
Vol 34 (4) ◽  
pp. 681 ◽  
Author(s):  
D Airey
Keyword(s):  
Ad Hoc ◽  
Eastern Coast ◽  
East Australian Current ◽  
Isothermal Temperature ◽  
Warm Core ◽  
Tasman Sea

Warm-core eddies off the eastern coast of Australia are characterized by their isothermal core temperatures. For coastal eddies, core temperatures correlate with the latitude of the eddy at the end of winter. The isothermal temperature is used to identify and track eddies. Eddy positions from 1976 to 1981 have been charted to show patterns in their formation, drift and interactions with other eddies and the East Australian Current. To date, eddies have been named alphabetically in an ad hoc way that has caused confusion because of the unexpected behaviour of some eddies. To overcome this, a systematic way of naming eddies is suggested, which takes into account the eddy's history.

Predicting changes in distribution of a large coastal shark in the face of the strengthening East Australian Current

2020 ◽  
Vol 642 ◽  
pp. 163-177 ◽  
Author(s):  
Y Niella ◽  
AF Smoothey ◽  
V Peddemors ◽  
R Harcourt
Keyword(s):  
Austral Summer ◽  
Conservation Strategies ◽  
Limiting Factor ◽  
Commercial Fisheries ◽  
East Australian Current ◽  
Spatial And Temporal Patterns ◽  
Marine Animals ◽  
Factors Affecting ◽  
Southeastern Australia ◽  
The Face

In the face of accelerating climate change, conservation strategies will need to consider how marine animals deal with forecast environmental change as well as ongoing threats. We used 10 yr (2009-2018) of data from commercial fisheries and a bather protection program along the coast of New South Wales (NSW), southeastern Australia, to investigate (1) spatial and temporal patterns of occurrence in bull sharks and (2) environmental factors affecting bull shark occurrence along the coast of NSW. Predicted future distribution for this species was modelled for the forecast strengthening East Australian Current. Bull sharks were mostly harvested in small to larger estuaries, with average depth and rainfall responsible for contrasting patterns for each of the fisheries. There was an increase in the occurrence of bull sharks over the last decade, particularly among coastal setline fisheries, associated with seasonal availability of thermal gradients >22°C and both westward and southward coastal currents stronger than 0.15 and 0.60 m s-1, respectively, during the austral summer. Our model predicts a 3 mo increase in the availability of favourable water temperatures along the entire coast of NSW for bull sharks by 2030. This coastline provides a uniquely favourable topography for range expansion in the face of a southerly shift of warmer waters, and habitat is unlikely to be a limiting factor for bull sharks in the future. Such a southerly shift in distribution has implications for the management of bull sharks both in commercial fisheries and for mitigation of shark-human interactions.

scholarly journals The Role of the New Zealand Plateau in the Tasman Sea Circulation and Separation of the East Australian Current

2018 ◽  
Vol 123 (2) ◽  
pp. 1457-1470 ◽  
Author(s):  
Christopher Y. S. Bull ◽  
Andrew E. Kiss ◽  
Erik van Sebille ◽  
Nicolas C. Jourdain ◽  
Matthew H. England
Keyword(s):  
New Zealand ◽  
East Australian Current ◽  
Tasman Sea

Investigations of the Tasman Sea by satellite altimetry

1984 ◽  
Vol 35 (6) ◽  
pp. 619 ◽  
Author(s):  
R Coleman
Keyword(s):  
Spatial Distribution ◽  
Satellite Data ◽  
Satellite Altimetry ◽  
Sea Surface ◽  
Altimeter Data ◽  
Winter Period ◽  
East Australian Current ◽  
Tasman Sea ◽  
Topographic Influence ◽  
Surface Variability

Altimeter data obtained over a period of 3.6 years (from April 1975 to November 1978) and over the winter period July-September 1978 from the GEOS-3 and SEASAT satellites were used to study the spatial distribution of mesoscale sea-surface variability in the Tasman Sea. Satellite data generally agreed with existing hydrographic measurements. Patterns of higher sea-surface variability were shown to be associated with the East Australian Current and eddy areas. Though the Tasman Front is known to be present at certain times of the year, it is concluded that it is not a permanent feature across the Tasman Sea. Low variability levels in the mid-Tasman Sea are seemingly dictated by the Lord Howe Rise, thus suggesting some sort of topographic influence.

Bass Strait water intrusions in the Tasman Sea and mean temperature-salinity curves

1981 ◽  
Vol 32 (5) ◽  
pp. 699 ◽  
Author(s):  
M Tomczak Jr
Keyword(s):  
Water Mass ◽  
East Australian Current ◽  
Shelf Edge ◽  
The South ◽  
The North ◽  
Mean Temperature ◽  
Tasman Sea

At temperatures of 8-18�C mean temperature-salinity curves for the Tasman Sea show slightly higher salinities in the south than in the north. It is shown that this is the effect of intrusions of Bass Strait Water which enters the Tasman Sea predominantly in winter and can be traced in individual stations over distances of 600 nautical miles along the shelf edge and 200 nautical miles offshore. The paths of individual intrusions and the degree of mixing are highly variable and seem to depend, among other factors, on the path of the East Australian Current and its eddies. This is interpreted as an indication that the eddies may play a major role in the formation of the water-mass characteristics of the Tasman Sea.

scholarly journals A numerical modeling study of the East Australian Current encircling and overwashing a warm-core eddy

2013 ◽  
Vol 118 (1) ◽  
pp. 301-315 ◽  
Author(s):  
H. S. Macdonald ◽  
M. Roughan ◽  
M. E. Baird ◽  
J. Wilkin
Keyword(s):  
Numerical Modeling ◽  
East Australian Current ◽  
Warm Core ◽  
Modeling Study
Sign in / Sign up

Export Citation Format

Share Document