Distribution of Thecosomatous Pteropods off the Central Coast of Western Australia

1978 ◽  
Vol 29 (6) ◽  
pp. 853
Author(s):  
FE Wells
Keyword(s):  
Indian Ocean ◽  
Western Australia ◽  
General Context ◽  
Central Coast ◽  
The Indian Ocean ◽  
The Mean

A series of surface plankton tows was made along eight transects in the Indian Ocean off the central coast of Western Australia during June 1976. The transects were spaced 1� 30' apart latitudinally from 24� 30'S. to 35� 00'S. and stretched from the coast westward to 105� E. Fifteen species and subspecies of the cosomatous pteropods were collected during the survey. The mean total the cosome density was 5.61 per 10³ m³ of water filtered. Four species (Cavolinia inflexa, Clio pyramidata, Cuvierina columnella and Styliola subula) together constituted 87.3 % of all the cosomes collected. The results of this survey are placed into the general context of our knowledge of the zooplankton off Western Australia.

Interannual Rainfall Extremes over Southwest Western Australia Linked to Indian Ocean Climate Variability

2006 ◽  
Vol 19 (10) ◽  
pp. 1948-1969 ◽  
Author(s):  
Matthew H. England ◽  
Caroline C. Ummenhofer ◽  
Agus Santoso
Keyword(s):  
Indian Ocean ◽  
Western Australia ◽  
Wind Field ◽  
Large Scale ◽  
Extreme Rainfall ◽  
Ekman Transport ◽  
Eastern Indian Ocean ◽  
Basin Scale ◽  
Rainfall Extremes ◽  
The Indian Ocean

Abstract Interannual rainfall extremes over southwest Western Australia (SWWA) are examined using observations, reanalysis data, and a long-term natural integration of the global coupled climate system. The authors reveal a characteristic dipole pattern of Indian Ocean sea surface temperature (SST) anomalies during extreme rainfall years, remarkably consistent between the reanalysis fields and the coupled climate model but different from most previous definitions of SST dipoles in the region. In particular, the dipole exhibits peak amplitudes in the eastern Indian Ocean adjacent to the west coast of Australia. During dry years, anomalously cool waters appear in the tropical/subtropical eastern Indian Ocean, adjacent to a region of unusually warm water in the subtropics off SWWA. This dipole of anomalous SST seesaws in sign between dry and wet years and appears to occur in phase with a large-scale reorganization of winds over the tropical/subtropical Indian Ocean. The wind field alters SST via anomalous Ekman transport in the tropical Indian Ocean and via anomalous air–sea heat fluxes in the subtropics. The winds also change the large-scale advection of moisture onto the SWWA coast. At the basin scale, the anomalous wind field can be interpreted as an acceleration (deceleration) of the Indian Ocean climatological mean anticyclone during dry (wet) years. In addition, dry (wet) years see a strengthening (weakening) and coinciding southward (northward) shift of the subpolar westerlies, which results in a similar southward (northward) shift of the rain-bearing fronts associated with the subpolar front. A link is also noted between extreme rainfall years and the Indian Ocean Dipole (IOD). Namely, in some years the IOD acts to reinforce the eastern tropical pole of SST described above, and to strengthen wind anomalies along the northern flank of the Indian Ocean anticyclone. In this manner, both tropical and extratropical processes in the Indian Ocean generate SST and wind anomalies off SWWA, which lead to moisture transport and rainfall extremes in the region. An analysis of the seasonal evolution of the climate extremes reveals a progressive amplification of anomalies in SST and atmospheric circulation toward a wintertime maximum, coinciding with the season of highest SWWA rainfall. The anomalies in SST can appear as early as the summertime months, however, which may have important implications for predictability of SWWA rainfall extremes.

Seasonal variations in the Indian Ocean along 110°E. III. Chlorophylls a and c

1969 ◽  
Vol 20 (1) ◽  
pp. 55 ◽  
Author(s):  
GF Humphrey ◽  
JD Kerr
Keyword(s):  
Regression Analysis ◽  
Indian Ocean ◽  
Water Column ◽  
Chlorophyll A ◽  
Seasonal Variations ◽  
The Indian Ocean ◽  
The Mean

The mean concentrations for all samples analysed were 0.17 �g/l for chlorophyll a and 0.22 �g/I. for chlorophyll c; there were 27 mg/m² of a and 35 mg/m² of c in the water column to 150 m. June-August gave the highest values. The model depth at which concentrations were greatest was 75 m. Diagrams of regression surfaces fitted to the results are given. Regression analysis showed that depth, latitude, and season affected the concentration of chlorophylls; latitude and season affected the column amount of chlorophylls.

scholarly journals Annual, Seasonal, and Interannual Variability of Air–Sea Heat Fluxes in the Indian Ocean

2007 ◽  
Vol 20 (13) ◽  
pp. 3190-3209 ◽  
Author(s):  
Lisan Yu ◽  
Xiangze Jin ◽  
Robert A. Weller
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Interannual Variability ◽  
Seasonal Cycle ◽  
Arabian Sea ◽  
Heat Fluxes ◽  
The Other ◽  
Net Heat Flux ◽  
The Indian Ocean ◽  
The Mean

Abstract This study investigated the accuracy and physical representation of air–sea surface heat flux estimates for the Indian Ocean on annual, seasonal, and interannual time scales. Six heat flux products were analyzed, including the newly developed latent and sensible heat fluxes from the Objectively Analyzed Air–Sea Heat Fluxes (OAFlux) project and net shortwave and longwave radiation results from the International Satellite Cloud Climatology Project (ISCCP), the heat flux analysis from the Southampton Oceanography Centre (SOC), the National Centers for Environmental Prediction reanalysis 1 (NCEP1) and reanalysis-2 (NCEP2) datasets, and the European Centre for Medium-Range Weather Forecasts operational (ECMWF-OP) and 40-yr Re-Analysis (ERA-40) products. This paper presents the analysis of the six products in depicting the mean, the seasonal cycle, and the interannual variability of the net heat flux into the ocean. Two time series of in situ flux measurements, one taken from a 1-yr Arabian Sea Experiment field program and the other from a 1-month Joint Air–Sea Monsoon Interaction Experiment (JASMINE) field program in the Bay of Bengal were used to evaluate the statistical properties of the flux products over the measurement periods. The consistency between the six products on seasonal and interannual time scales was investigated using a standard deviation analysis and a physically based correlation analysis. The study has three findings. First of all, large differences exist in the mean value of the six heat flux products. Part of the differences may be attributable to the bias in the numerical weather prediction (NWP) models that underestimates the net heat flux into the Indian Ocean. Along the JASMINE ship tracks, the four NWP modeled mean fluxes all have a sign opposite to the observations, with NCEP1 being underestimated by 53 W m−2 (the least biased) and ECMWF-OP by 108 W m−2 (the most biased). At the Arabian Sea buoy site, the NWP mean fluxes also have an underestimation bias, with the smallest bias of 26 W m−2 (ERA-40) and the largest bias of 69 W m−2 (NCEP1). On the other hand, the OAFlux+ISCCP has the best comparison at both measurement sites. Second, the bias effect changes with the time scale. Despite the fact that the mean is biased significantly, there is no major bias in the seasonal cycle of all the products except for ECMWF-OP. The latter does not have a fixed mean due to the frequent updates of the model platform. Finally, among the four products (OAFlux+ISCCP, ERA-40, NCEP1, and NCEP2) that can be used for studying interannual variability, OAFlux+ISCCP and ERA-40 Qnet have good consistency as judged from both statistical and physical measures. NCEP1 shows broad agreement with the two products, with varying details. By comparison, NCEP2 is the least representative of the Qnet variabilities over the basin scale.

scholarly journals COMPARISON OF INDONESIAN TUNA LONGLINE FISHING PERFORMANCE WITHIN AND OUTSIDE INDONESIA EXCLUSIVE ECONOMIC ZONE (EEZ)

2017 ◽  
Vol 23 (1) ◽  
pp. 1
Author(s):  
Bram Setyadji ◽  
Irwan Jatmiko
Keyword(s):  
Indian Ocean ◽  
Bluefin Tuna ◽  
T Test ◽  
Exclusive Economic Zone ◽  
Southern Bluefin Tuna ◽  
The Indian Ocean ◽  
The Mean ◽  
Economic Zone ◽  
Tuna Longline ◽  
High Seas

Indonesian tuna longline fleets have been fishing in the Exclusive Economic Zone (EEZ) and high seas of the Indian Ocean for quite some time. However, effort has never been made to separate catch from the EEZ and the high seas as it important for fisheries management. A total of 2,430 set-by-set longline fishing data had been collected by scientific observers based in the Research Institute of Tuna Fishery in Bali since August 2005 to December 2014 on which present analysis was made. The research aims to compare between trend of tuna catch of the EEZ and of the high seas of Indian Ocean. The results show that the mean hook rate of both catches of big eye tuna (BET) and southern Bluefin tuna (SBT) caught in the high seas was significantly higher than that the EEZ (two sample t-test, p<0.05), while for yellow fin tuna (YFT) it was in the opposite direction (two sample t-test, p<0.05). As for albacore (ALB), the mean hook rate value was statistically similar in both fishing grounds (two sample t-test, p>0.05).

scholarly journals Two new species of Eulepethidae (Polychaeta) from Australian seas

Zootaxa ◽  
2011 ◽  
Vol 2839 (1) ◽  
pp. 47
Author(s):  
SKIPTON WOOLLEY ◽  
ROBIN S. WILSON
Keyword(s):  
New Species ◽  
Indian Ocean ◽  
South China Sea ◽  
Western Australia ◽  
Continental Margin ◽  
World Wide ◽  
Southeastern Australia ◽  
The Family ◽  
Two New Species ◽  
The Indian Ocean

Exploration of poorly known regions of the Australian continental margin has resulted in the discovery of two new species in the scale worm family Eulepethidae. Grubeulepis kurnai sp. nov. occurs in southeastern Australia while Proeulepethus payungu sp. nov. was collected at one site in the Indian Ocean on the continental margin of Western Australia. Pareulepis malayana (Horst, 1913), also collected from the continental margin of Western Australia, is newly recorded from Australia, representing a range extension of that species previously known from Madagascar, Malaysia and the South China Sea. Four species, and four of the six known genera of Eulepethidae are now known from Australian waters. The family Eulepethidae remains species-poor compared with most polychaete families, and now comprises 21 species world wide.

scholarly journals Strong Intraseasonal Variability of Meridional Currents near 5°N in the Eastern Indian Ocean: Characteristics and Causes

2017 ◽  
Vol 47 (5) ◽  
pp. 979-998 ◽  
Author(s):  
Gengxin Chen ◽  
Weiqing Han ◽  
Yuanlong Li ◽  
Michael J. McPhaden ◽  
Ju Chen ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Rossby Waves ◽  
Intraseasonal Variability ◽  
Upper Ocean ◽  
Mean Flow ◽  
Eastern Boundary ◽  
Typical Period ◽  
The Indian Ocean ◽  
The Mean

AbstractThis paper reports on strong, intraseasonal, upper-ocean meridional currents observed in the Indian Ocean between the Bay of Bengal (BOB) and the equator and elucidates the underlying physical processes responsible for them. In situ measurements from a subsurface mooring at 5°N, 90.5°E reveal strong intraseasonal variability of the meridional current with an amplitude of ~0.4 m s−1 and a typical period of 30–50 days in the upper 150 m, which by far exceeds the magnitudes of the mean flow and seasonal cycle. Such prominent intraseasonal variability is, however, not seen in zonal current at the same location. Further analysis suggests that the observed intraseasonal flows are closely associated with westward-propagating eddylike sea surface height anomalies (SSHAs) along 5°N. The eddylike SSHAs are largely manifestations of symmetric Rossby waves, which result primarily from intraseasonal wind stress forcing in the equatorial waveguide and reflection of the equatorial Kelvin waves at the eastern boundary. Since the wave signals are generally symmetric about the equator, similar variability is also seen at 5°S but with weaker intensity because of the inclined coastline at the eastern boundary. The Rossby waves propagate westward, causing pronounced intraseasonal SSHA and meridional current in the upper ocean across the entire southern BOB between 84° and 94°E. They greatly weaken in the western Indian Basin, but zonal currents near the equator remain relatively strong.

Lasionectes exleyi, sp, nov., the first remipede crustacean recorded from Australia and the Indian Ocean, with a key to the world species

1996 ◽  
Vol 10 (1) ◽  
pp. 171 ◽  
Author(s):  
J Yager ◽  
WF Humphreys
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Western Australia ◽  
The Bahamas ◽  
World Species ◽  
Density Interface ◽  
The World ◽  
First Occurrence ◽  
The Indian Ocean

The first remipede crustacean from the Southern Hemisphere and the Indian Ocean is reported. Lasionectes exleyi, sp. nov., is described from an anchialine cave on the Cape Range peninsula of Western Australia. This is the eleventh species of modern remipede to be described and the second species to be described in the genus Lasionectes. A key to all known species is presented. The discovery of remipedes in Australia represents the first occurrence of a genus other than Speleonectes off the Bahamas Banks and only the second continental occurrence of extant remipedes. The species is known from below a density interface in a single nutrient-enriched cave.

scholarly journals Platycephalus orbitalis, a new species of flathead (Teleostei: Platycephalidae) collected from western Australia

Zootaxa ◽  
2009 ◽  
Vol 2271 (1) ◽  
pp. 57-63 ◽  
Author(s):  
HISASHI IMAMURA ◽  
LESLIE W. KNAPP
Keyword(s):  
New Species ◽  
Indian Ocean ◽  
Western Australia ◽  
Posterior Margin ◽  
Morphological Characters ◽  
The Body ◽  
The Other ◽  
Eastern Australia ◽  
The Indian Ocean ◽  
A New Species

A new plataycephalid, Platycephalus orbitalis, is described on the basis of specimens collected in the Indian Ocean off the coast of Western Australia at depths of 50–144 m. The new species had been mistakenly identified as P. marmoratus, which is now known to be restricted to eastern Australia. Several morphological characters (e.g, 65–68 pored scales in lateral line, snout and interorbit naked, and caudal fin blackish with white posterior margin) can separate Platycephalus orbitalis sp. nov. and P. marmoratus from the other 14 congeners. In addition, Platycephalus orbitalis sp. nov. differs from P. marmoratus in having the margin of the interopercle scalloped, skinny sensory tubes on the infraorbitals, the preopercle well developed and mostly covering the cheek region, and the body and head lacking distinct large spots and bands dorsally.

Multitestis Manter 1931 (Digenea: Lepocreadiidae) in ephippid and chaetodontid fishes (Perciformes) in the south-western Pacific Ocean and the Indian Ocean off Western Australia

Zootaxa ◽  
2010 ◽  
Vol 2427 (1) ◽  
pp. 36 ◽  
Author(s):  
RODNEY A. BRAY ◽  
THOMAS H. CRIBB ◽  
JEAN-LOU JUSTINE
Keyword(s):  
Indian Ocean ◽  
Great Barrier Reef ◽  
Western Australia ◽  
Body Shape ◽  
New Caledonia ◽  
Western Pacific Ocean ◽  
Barrier Reef ◽  
Lizard Island ◽  
The Indian Ocean ◽  
Oval Body

Five species of the genus Multitestis are described, figured or discussed: Multitestis pyriformis from Platax orbicularis off Lizard Island, northern Great Barrier Reef, Australia and Platax teira off New Caledonia; Multitestis coradioni n. sp. (syn. Multitestis pyriformis Machida, 1963 of Bray et al. (1994)) from Coradion chrysozonus off Heron Island, which differs from M. pyriformis in its oval body-shape, the more posteriorly situated testicular fields and larger eggs, Multitestis elongatus from Platax pinnatus off Lizard Island, Multitestis magnacetabulum from P. teira off Heron Island, southern Great Barrier Reef, Australia, and New Caledonia, Multitestis paramagnacetabulum n. sp. from P. orbicularis off Ningaloo Reef, Western Australia, which differs from M. magnacetabulum in the more posteriorly situated testicular fields.

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