Seasonal variations in the Indian Ocean along 110°E. V. Zooplankton biomass

1969 ◽  
Vol 20 (1) ◽  
pp. 77 ◽  
Author(s):  
DJ Tranter ◽  
JD Kerr
Keyword(s):  
Indian Ocean ◽  
Central Region ◽  
Seasonal Variations ◽  
Zooplankton Biomass ◽  
General Level ◽  
Average Value ◽  
The Indian Ocean

Samples of the zooplankton in the upper 200 m were taken with the Indian Ocean Standard Net and Clarke-Bumpus sampler, and their wet weights were determined. Biomass ranged from 3 to 525 mg/m³, the general level being 25-100 mg/m³. The average value by day was 0.6 times that by night. Biomass was fairly uniform over a wide central region (16-27� S.), increasing further north and decreasing further south. The biomass was greatest in September and March and least in December and June.

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.

Seasonal variations in the Indian Ocean along 110°E. II. Particulate carbon

1969 ◽  
Vol 20 (1) ◽  
pp. 51 ◽  
Author(s):  
BS Newell
Keyword(s):  
Indian Ocean ◽  
Seasonal Variations ◽  
Combustion Method ◽  
Particulate Material ◽  
Particulate Carbon ◽  
The Indian Ocean

Particulate carbon at 0, 50, 100, 150, and 200 m was measured by a combustion method. Mineral carbon appeared to be negligible. Some particulate material escaped the Whatman GF/C filters used. The amount of suspended carbon decreased with depth at most stations from values of 20 �g/l, or more at 0 and 50 m, to 15 �g/l, at 150 m, and 10�g/l, at 150 and 200m. Higher values were found at all depths at the two southernmost stations (25-30 �g/I. at 0 and 50 m decreasing to 15 �gll. at 150 and 200 m ) and at shallow depths at the northernmost stations (20-25 �g/l. at 0 and 50m). At all stations and at all depths, least carbon occurred in March.

scholarly journals Dynamics of the seasonal variations in the Indian Ocean from TOPEX/POSEIDON sea surface height and an ocean model

1998 ◽  
Vol 25 (11) ◽  
pp. 1915-1918 ◽  
Author(s):  
Jiayan Yang ◽  
Lisan Yu ◽  
Chester J. Koblinsky ◽  
David Adamec
Keyword(s):  
Indian Ocean ◽  
Seasonal Variations ◽  
Sea Surface Height ◽  
Ocean Model ◽  
Sea Surface ◽  
The Indian Ocean

Seasonal variations in the Indian Ocean along 110°E. IV. Primary production

1969 ◽  
Vol 20 (1) ◽  
pp. 65 ◽  
Author(s):  
HR Jitts
Keyword(s):  
Indian Ocean ◽  
Primary Production ◽  
Seasonal Variations ◽  
High Productivity ◽  
Photosynthetic Organisms ◽  
South Indian ◽  
Daily Rate ◽  
Deep Layers ◽  
Equatorial Upwelling ◽  
The Indian Ocean

Mean productivity (light saturated photosynthesis), Ps, for the meridian rose from 50 mg C/(hr m²) in August 1962 to a maximum of 62 in October, then fell to a minimum of 4 in January, whereafter it rose slowly to 25 in April-May, then sharply to 45 in late May, and remained at that level till August 1963. Mean Ps for the year was 37 mg C/(hr m²). The depth of the layer of photosynthetic organisms varied between 130 m in October and 60 m in January, with a mean of 85 m. Maximum Ps occurred at 25 m in 36% of the stations, at 0 m in 29 %, and at 50 m in 24%. In January-February the whole meridian was occupied by waters of low productivity, approximately 4 mg C/(hr m²) from the centre of the south Indian Ocean. In April-May the Ps remained uniform along the meridian but rose to 24. At other times four latitudinal intervals along the meridian, with distinctive seasonal variations of productivity characteristics, were found. From 9 to 15°S., waters with high Ps (69 mg C/(hr m²)), and sharp stratification at 50 m, caused by equatorial upwelling, occurred from May to October. From 15 to 24 and 24 to 30°S., waters with high Ps (60 mg Cl(hr m²) and (100 m) deep layers of photosynthetic organisms were found during October-November and May-July respectively. From 30 to 32�S., waters of high productivity (70 mg C/(hr m²)) and a deep layer (100 m) were found in the period July-August. The daily rate of primary production, Pa, of the whole meridian varied from 0.13 g C/(day m²) in August to 0.08 from October to early May, rising sharply in late May to 0.18 and again in early August to 0.27. The depth of the euphotic layer varied between 76 m in October and 63 m in July-August, with a mean of 68 m.

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