Indian Ocean abundances

Like the Atlantic, the Indian Ocean is characterized by foram oozes along its mid-ocean ridge and most of its abyssal plains. Only in basins where the water depths exceed 5000 m are abyssal clays abundant. 

In addition to the species mentioned, there are others that also introduced from the near-shore waters of the Pacific or Indian oceans after the opening of the Suez Canal initially, they established in the coastal waters of Europe and the Adriatic Sea and then were driven to the Black Sea. These are the poly-chaets Capitellethus dispar and Glycera carpita, the gastropod Potamopyrgus jenkinsi, and the decapod—Chinese mitten crab Eriocheir sinensis. However, these invaders have not become abundant species in the Black Sea. 

D.M. SHENOY M. DILEEP KUMAR / Variability in abundance and fluxes of dimethyl sulphide in the Indian Ocean 277-292... 

Variability in abundance and fluxes of dimethyl sulphide in the Indian Ocean... 

In DMS flux calculations it is assumed that DMS in air is negligible compared to that in seawater and therefore the concentration difference used in the flux calculation is essentially equal to DMS concentration in seawater. Figure 10 depicts variations in surface DMS flux in the coastal and open ocean areas of the Indian Ocean. The DMS fluxes from the coastal waters of India are lower than that from the open Ocean. Higher DMS fluxes in the central Indian Ocean are associated with higher DMS abundance and high wind speeds in winter of 1999. In the coastal areas the DMS flux varied between 0.04 pmol m-2 d 1 and... 

In the Indian Ocean, near surface values of N are sHghdy elevated (Gruber and Samfrento, 1997). As these elevated values are located just above some of the lowest A/ values found anywhere in the world oceans, they suggest rather strong N2 fixation. Observations of Trichodesmium abundance (Carpenter, 1983) and a few direct rate measurements (reported in Capone et al. (1997)) support this conclusion. The low A/ concentrations in the thermocHne of the Arabian Sea (Fig. 1.12)... 

Figure 13 Nd abundance versus (a) salinity and (b) silicate in deep seawater. Nd concentrations do not show the same well-behaved characteristics as Nd-isotope ratios with salinity and silicate in global deep water. Mixing envelopes are shown between North Atlantic and Pacific end-members, and the circum-Antarctic, South Atlantic, and Indian Ocean samples fall outside of it. Plotted data are from >2,500 mb si, except two Drake Passage data from 1,900 m and 2,000 m (Nd data sources Piepgras and Wasserburg, 1980, 1982, 1983, 1987 Spivack and Wasserburg, 1988 Piepgras and Jacobsen, 1988 Bertram and Elderfield, 1993 Jeandel, 1993 Shimizu et al., 1994 Jeandel et ah, 1998). Where salinity or silicate were not available in the publication, they were estimated from Levitus (1994),...

Smith, S.L. (1982) The northwestern Indian Ocean during the monsoons of 1979 Distribution, abundance and feeding of zooplankton. Deep-Sea Research, 29, 1331-1353. 

Wiebinga, C.J., Veldhuis, M.J.W. and DeBaar, H J.W. (1997) Abundance and productivity of bacterio-plankton in relation to seasonal upwelling in the northwest Indian Ocean. Deep-Sea Research I, 44, 451—476. 

Pacific Ocean Atiantic Ocean indian Ocean Southern Ocean World Ocean average Crustai abundance Enrichment factor Shallow marine Lakes... 

Atlantic Ocean Nodule abundance in the Atlantic Ocean appears to be more limited than in the Pacific or Indian Oceans, probably as a result of its relatively high sedimentation rates. Another feature which inhibits nodule abundance in the Atlantic is that much of the seafloor is above the calcium carbonate compensation depth (CCD). The areas of the Atlantic where nodules do occur in appreciable amounts are those where sedimentation is inhibited. The deep water basins on either side of the Mid-Atlantic Ridge which are below the CCD and which accumulate only limited sediment contain nodules in reasonable abundance, particularly in the western Atlantic. Similarly, there is a widespread occurrence of nodules and encrustations in the Drake Passage-Scotia Sea area probably due to the strong bottom currents under the Circum-Antarctic current inhibiting sediment deposition in this region. Abundant nodule deposits on the Blake Plateau can also be related to high bottom currents. 

Marine processes. Sea water reacts with ocean-bed sediments containing volcanic ash, or biogenic silica from Radiolarians, to form zeolites. This process is common in deep-sea sediments and phillipsite makes up 80% of the sediment in the Indian and Pacific Oceans. Clinoptilolite is abundant in Atlantic sediments and both phillipsite and clinoptilolite are found in manganese nodules on the ocean beds. 

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