scholarly journals Effects of a Warm-Core Eddy on Fish Distributions in the Tasman Sea of East Australia

1981 ◽  
Vol 6 ◽  
pp. 19-33 ◽  
Author(s):  
SB Brandt
Keyword(s):  
Warm Core ◽  
Tasman Sea ◽  
Fish Distributions

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.

Hyperiid amphipods (Crustacea : Peracarida) from a warm-core eddy in the Tasman Sea

1987 ◽  
Vol 38 (6) ◽  
pp. 711 ◽  
Author(s):  
JW Young
Keyword(s):  
Life History ◽  
Vertical Distribution ◽  
Breeding Season ◽  
New Records ◽  
Abundant Species ◽  
Geographic Range ◽  
Gelatinous Zooplankton ◽  
Warm Core ◽  
Coral Sea ◽  
Tasman Sea

Hyperiid amphipods were sampled from a warm-core eddy in the Tasman Sea in August, September and October 1979. Samples were taken at night to a depth of 400 m using a midwater trawl (RMT-8). In all, 22 798 hyperiids representing 38 species and 10 families were identified, adding 13 new records for eastern Australian waters. For each species, synoptic information is given on taxonomy, life history, vertical distribution, geographic range and associations with gelatinous zooplankton. Hyperiids were confined mainly to the upper 100 m of water at night. Evidence for a summer breeding season was found in three abundant species (Scina crassicornis, Primno johnsoni and Brachyscelus crusculum). Tropical hyperiid species may be transported into the Tasman Sea by the southward movement of eddies from their origin in the Coral Sea.

scholarly journals Tropical Transition of the 2001 Australian Duck

2010 ◽  
Vol 138 (6) ◽  
pp. 2038-2057 ◽  
Author(s):  
Luke Andrew Garde ◽  
Alexandre Bernardes Pezza ◽  
John Arthur Tristram Bye
Keyword(s):  
Potential Vorticity ◽  
Large Scale ◽  
Three Dimensional ◽  
Vertical Wind Shear ◽  
Heat Fluxes ◽  
Pressure System ◽  
Surface Heat Fluxes ◽  
Warm Core ◽  
Tasman Sea ◽  
Upper Level

Abstract In March 2001, a hybrid low pressure system, unofficially referred to as Donald (or the Duck), developed in the Tasman Sea under tropical–extratropical influence, making landfall on the southeastern Australian coast. Here, it is shown that atmospheric blocking in the Tasman Sea produced a split in the subtropical jet, allowing persistent weak vertical wind shear to manifest in the vicinity of the developing low. It is hypothesized that this occurred through sustained injections of potential vorticity originating from higher latitudes. Hours before landfall near Byron Bay, the system developed an eye with a short-lived warm core at 500 hPa. Cyclone tracking revealed an erratic track before the system decayed and produced heavy rains and flash flooding. A three-dimensional air parcel backward-trajectory scheme showed that the air parcels arriving in the vicinity of the mature cyclone originated from tropical sources at lower levels and from the far extratropics at higher levels, confirming the hybrid characteristics of this cyclone. A high-resolution (0.15°) nested simulation showed that recent improvements in the assimilation scheme used by the Australian models allowed for accurately simulating the system’s trajectory and landfall, which was not possible at the time of the event. Compared to the first South Atlantic hurricane of March 2004, the large-scale precursors were similar; however, the Duck was exposed to injections of upper-level potential vorticity and favorable surface heat fluxes for a shorter period of time, resulting in it achieving partial tropical transition only hours prior to landfall.

Geographical distribution of living planktonic foraminifera (Protozoa) off the east coast of Australia.

1988 ◽  
Vol 39 (1) ◽  
pp. 71 ◽  
Author(s):  
S Andrijanic
Keyword(s):  
Sea Water ◽  
Planktonic Foraminifera ◽  
Distribution Patterns ◽  
Water Masses ◽  
Individual Species ◽  
The South ◽  
The North ◽  
Warm Core ◽  
Tasman Sea ◽  
Eastern Australia

Major water masses found off eastern Australia can be identified by their planktonic foraminiferal faunas. A total of 83 surface and oblique plankton samples from two cruises, in spring (October) and summer (January), between Hobart at 44� S. and Townsville at 18� S. yielded 27 species belonging to four distinct faunas: 'tropical', 'warm subtropical', 'cool subtropical' and 'transitional'. The tropical fauna is characterized by Globigerinoides sacculifer at an abundance greater than 42% and the co- dominance of Globigerinoides conglobatus, and is associated with Coral Sea water of equatorial origin. The subtropical fauna can be subdivided into warm and cool elements. The warm-subtropical fauna, with G. sacculifer more abundant than Globigerinoides ruber, inhabits Coral and Tasman Sea waters. The cool-subtropical fauna is a mixture of the warm subtropical and the transitional faunas. The transitional fauna is dominated by Globorotalia inflata and Globigerina bulloides in the south Tasman Sea subantarctic waters. It characterizes the South West Tasman water as defined by Rochford (1957). These water masses can be clearly separated, and the extent of mixing determined by their foraminiferal fauna. The shifts in the boundaries between the faunal zones was evident between spring and summer. The boundary between the tropical and subtropical water corresponds to the tropical convergence and the subtropical/transitional boundary is the Tasman Front. During the spring cruise, a warm core eddy was identified by its warm subtropical foraminiferal fauna surrounded by a transitional fauna to the south and cool subtropical fauna to the north. This water body was near 32� S., which is consistent with the reported positions of eddies shed by the East Australian Current. The distribution patterns of individual species are discussed.

Mesopelagic crustacea in and around a warm-core eddy in the Tasman Sea off eastern Australia

1983 ◽  
Vol 34 (4) ◽  
pp. 609 ◽  
Author(s):  
FB Griffiths ◽  
SB Brandt
Keyword(s):  
Secondary Succession ◽  
Water Mass ◽  
Sea Water ◽  
Abundant Species ◽  
Frequency Distributions ◽  
Warm Core ◽  
Tasman Sea ◽  
Eastern Australia ◽  
Decapod Crustacea ◽  
Species Abundances

Decapod Crustacea were collected during five cruises (in August, September, and October 1979, February and May 1980) at sites inside, at the edge, and outside of warm-core eddy J. These sampling sites were considered to have come from different domains of the Tasman Sea water mass. All 146 samples in this time series were taken in the upper 500 m at night using horizontal tows with an RMT 8. A total of 21 494 individuals belonging to 41 species and five larval categories was found. Nine of the 18 abundant species were cosmopolitan species: typical of samples from outside, at the edge of, and inside eddy J. Oplophorus spinosus was typical only at the eddy edge. Four species were typical of the outside and edge domains, and another four were typical of the inside and edge domains. Species abundances outside the eddy were dominated by Sergia prehensilis, Gennadas gilchristi, and Acanthephyra quadrispinosa. The first two species, plus Systellaspis debilis, were dominant at the eddy edge. Six species (Systellaspis debilis, Sergia prehensilis, Sergia scintillans, Sergia splendens, Sergestes atlanticus, and Parapandalas cf. richardi) were dominant at various times inside the eddy. There were no significant differences in the abundance of Sergia prehensilis in the three domains. Systellaspis debilis was significantly more abundant inside and at the eddy edge than outside the eddy, and Gennadas gilchristi was significantly more abundant outside and at the eddy edge than inside the eddy. An analysis of the community changes with time showed that the outside communities remained very similar in spite of the 5°30' change in latitude of eddy J between August 1979 and May 1980. In contrast, the inside communities were quite dissimilar between months, and there was no trend in this pattern. The edge communities were very similar except in May, when a large increase in the abundance of Gennadas gilchristi was found. Comparisons of communities between domains within each month showed the outside and edge communities were very similar over the entire period. In contrast, the outside and inside communities became increasingly different in time, mainly caused by changes in the abundances of species inside the eddy. The inside and edge communities were also quite different, but no consistent pattern in their dissimilarity with time was seen. Differences in the size-frequency distributions of Sergla prehensilis and Systellaspis debilis between domains through time suggest that breeding and recruitment were occumng at different times inside and outside the eddy. There was little evidence for colonization of the eddy by Tasman Sea species. We conclude that a secondary succession has been initiated, probably in response to the different physical and biological environments present inside eddy J as compared with the surrounding Tasman Sea.

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