1 Chapter 1Table 1.1 Summarizes the calculated depth‐integrated sedimentary sulfate re...Table 1.2 Microbiological features of the well‐studied oxygen minimum zones...Table 1.3 Microbiological features of the well‐studied oxygen minimum zones...

      2 Chapter 3Table 3.1 List of iron‐reducing bacteria and archaea isolated from marine s...

      3 Chapter 4Table 4.1 Sedimentary denitrification rates in the Arabian Sea.Table 4.2 The δ¹⁵N of sinking particles from northern Indian Ocean.Table 4.3 The δ¹⁵N values in sediments from the northern Indian Ocean.

      4 Chapter 10Table 10.1 Groupwise distribution of major benthic species with record of e...

      5 Chapter 11Table 11.1 Summary of some of the studies carried out in the coastal region...Table 11.2 Antarctic microalgae endemism (Based on Broyer and Koubbi, 2015;...

      6 Chapter 12Table 12.1 Geographical, geological, and microbiological features of the we...Table 12.2 Main taxonomic groups detected corresponding to the individual m...Table 12.3 Metabolic processes that potentially operate in the brine cores ...

      7 Chapter 14Table 14.1 Hydrothermal vent fluid compositions for different vent fields a...Table 14.2 Updated list of benthic fauna associated with Indian Ocean vent ...Table 14.3 Details of the hydrothermal vent fauna in the Indian Ocean based...Table 14.4 List of the closely matching hydrothermal vent and cold‐seep fau...

      1 Chapter 1Figure 1.1 Global annual oxygen concentration (ml l^–1) at 150 mbsl....Figure 1.2 Annual oxygen concentration (μmol l^–1) in the water column ...Figure 1.3 Vertical distribution of oxygen (solid blue circle) and nitrite c...Figure 1.4 Global distribution pattern of particulate carbon flux to the sea...

      2 Chapter 2Figure 2.1 Homogeneous sulfur isotopic composition of modern seawater sulfat...Figure 2.2 (a) Simplified depth distribution of changes in porewater sulfate...Figure 2.3 Different generations of sedimentary pyrite with early diagenetic...Figure 2.4 (a) Variations in δ³⁴S for chromium reducible sulfur from bulk ro...Figure 2.5 Differentiation of different forms of microbial sulfur cycling as...Figure 2.6 Secular variations in δ³⁴S for carbonate‐associated sulfate (CAS:...Figure 2.7 Range in Δ³³S for sedimentary sulfide and sulfate exhibiting mass...

      3 Chapter 3Figure 3.1 Concentrations and activities of reduced iron and sulfide in seaw...Figure 3.2 Schematic porewater profiles and dominant microbial groups throug...Figure 3.3 Schematic diagram of redox potentials of enzymes in the cascade o...Figure 3.4 Schematic of multiheme cytochromes involved in transporting elect...Figure 3.5 Dissolved iron concentrations and depth stratification in communi...Figure 3.6 Phylogenetic tree of iron‐reducing bacteria and archaea isolated ...

      4 Chapter 4Figure 4.1 A simplified schematic diagram of nitrogen cycling in the global ...Figure 4.2 The major N cycling pathways and the marker genes associated with...Figure 4.3 Mechanism of electron flow during biological N₂ fixation.Figure 4.4 Nitrogen assimilation pathways in cyanobacteria. Glu, glutamate; ...Figure 4.5 Model for NH₃ oxidation to NO₂ ^– in AOB (Caranto and Lancas...Figure 4.6 Mineralization in the N cycle.Figure 4.7 Vertical profile of nitrogen isotope of sinking particulates from...

      5 Chapter 5Figure 5.1 (a) Schematic diagram showing transfer of organic carbon from sur...Figure 5.2 Bathymetric contours from the western margin of India, gray area ...Figure 5.3 One of the oldest contour maps showing organic carbon distributio...Figure 5.4 (a) Distribution of organic carbon (OC) in the surface sediments ...Figure 5.5 Maps showing the distribution of organic carbon