Oceanography Syllabus PDF

# SYLLABUS ## OCEANOGRAPHY - OBR (Ocean Bottom Relief) - LOS (Law of seas/Geopolitical division of ocean) - Salinity & temperature - Global warming and its impact on temperature - Sea Level change and global warming - Tides - types, origin, and distribution, influence on coastal climate, fishing be...

# SYLLABUS ## OCEANOGRAPHY - OBR (Ocean Bottom Relief) - LOS (Law of seas/Geopolitical division of ocean) - Salinity & temperature - Global warming and its impact on temperature - Sea Level change and global warming - Tides - types, origin, and distribution, influence on coastal climate, fishing belts - Ocean Currents - warm, cold - Thermo Helling Circulation - AMOC (Atlantic Meridional Overturning Current) - Marine Resources, Biotic resource, Mineral resource - Coral reef, Coral breaching ## 1. OCEAN BOTTOM RELIEF - Ocean bottom has even more complex topographical features than the continents. - They have the longest series of mountains called "ridges" and the deepest trenches, widest basins, and a layer of thick sediments rolling over these features known as ocean deposits. - Primarily, OBR is classified into: - **Continental Margins** - **Primary Relief** - **Secondary Relief** - Continental Shelf - Continental Slope - Continental Rise - Ridges - Basins - Trenches - Reef, Banks - Canyons - Furrows - **Tertiary Relief** - Sea Mounts - Sea Hills - Guyots (Flat seamount) - Knots - Cracks - Deep - **Abyssal Plain/Deep Sea** - **Continental Shelf** - Extends up to 2000m - Slope angle ≤ 1° - Widest: Where coastline is stable and wave action has been long endured - 45-55° N latitude in the Atlantic - Can be both erosional and depositional, some are tectonic - Width = 75km - Narrowest along the "Convergent plate boundary" (e.g. western coast of America) - Continental shelf covers ~ 7.5% of the total oceanic area. - **Continental Slope** - Erosional feature & has moving sediments - 8.5% of total area - It is steep along "Ist Helena" (near Brazil) - Angle = 25-40° (Normally slope angle is 3-5°) - Depth range: 200m to 3650m - **Continental Rise** - Depositional feature - 8.5% of total oceanic area - Transition between oceanic crust and continental crust - Contains both continental sediments and oceanic sediment - Separated from the deep-sea plains by trenches, especially along the "Convergent plate boundary" (subduction) - **Abyssal Plain/Deep Sea Plain**: - Flat, rolling plain divided into basins by ridges - 82.5% of total area - Slope angle = 1:1000 - Covered with ocean deposits mainly pelagic deposits (open ocean) - Oozes (dead organic deposits) - Red Clay (greasy) ## 2. LAW OF THE SEA (Geo-Political Division of Ocean) - **UNCLOS-1** (UN's Convention on Law of the sea) - Held in Geneva (Switzerland) - EEZC (Exclusive fishing zone) extending up to 200 nautical miles was permitted for the littoral (coastal) countries. - **UNCLOS-2**, 1972, Newyork: inconclusive - **UNCLOS-3**, Geneva - EEZE > 200 nautical miles - **The Law of Sea Act, 1982 Dt envisages**: - **Inland** - It includes lagoons, backwaters, estuaries (erosional) and islands (capturing sea) - **Territorial water** - It extends up to 12 nautical mile (sea) from baseline (up to 24 nautical mile), 1 nautical mile = 1.8 km from baseline (sea). - **Contiguous zone** - The sovereign power of a country extends over the territorial water - it extends up to 12 nautical mile. It's a "hot pursuit zone" - **Limited uses**: - Investigation and researches on be conducted (eg: Economic Exploitation is permitted) - Free movement of Navy coast guard; but cannot stop the ships and vessels afloat. - Anchoring of ships and vessels are not permitted - No permanent structures or naval bases - Enemies cannot be chased or pursuit beyond contagious zone (24 nautical miles) - **EEZE**: 200 nautical miles/mineral/Navy - **Open Ocean/High sea**: beyond 200 nautical miles, no country has sovereign rights - Economic rights fopen for world trade or free movement of vessels - Blue Waters - colonial term - Currently used to denote the presence of super powers in the high sea (eg. Diego Garcia ← Island in IOR, USA) ## 3. SALINITY & TEMPERATURE - **Salinity**: The total amount of dissolved material in the sea water, measured as gms/ kg or parts/thousand (‰) (ppt). - **Salinity = Evaporites X 1.8** - **Sources of salinity** - Terrestrial (91.8%) - River wind + waves - Extra (0.1%) - Meteoric Dust - Submarine (2.1%) - Ridges - Oozes- Brine (sum of salt) - **Factors or Determinants of salinity**: - **Insolation** & **Evaporation**: Highest rate of evaporation: tropics (Exposed to sunlight) - Highest along equator - **Precipitation**: Higher at equator - **Winds**: No landmass, winds tend to rate of evaporation (eg: 40-50° S), prevailing winds flow south - **Influx of river water & Ice melt water**: Southern Hemisphere has more salinity among these latitudes than North Hemisphere. - **Ocean Current**: Cold current - less salinity, warm current - more salinity, greater dissolving capability. - **Biota** (Animal + Plant) - They moderate the salinity ## 4. Distribution of Salinity - **Hemispherical S.** - North Hemisphere < South Hemisphere - Why? - Presence of rivers, continents, iceshelfs contributes in fresh water addition - **Latitudinal Salinity**: - 55° - 70° N = 31-33% - (NH) 25° - 15° S = 33-35% (Less) - (25) 15° - 10° S = 34.5% - 10° S - 30° S = 36-37% - (SH) 30° - 40° S = 35-36% (More) - 40° - 50° S = 34-35% - 50° - 60° S = 33-34% - **Salinity in general, declines from Equator to pole (T decrease away from tropics = CTV)** - **Ta Salinity < CTV** - **Salinity & S = true** - **T = false** - **Bay of Bengal v/s Arabian Sea** - Rainfall : 300cm (more open sea in the East) v/s 150cm (comparatively less rivers) - **Baltic Sea v/s No Sea (At same Latitude)** - North Atlantic Drift - More salinity (warm current), while Baltic Sea has more rivers & iceshelf ## 5. Distribution of salinity with depth: - **Equator**: - Up to 5m = low (Due to precipitation / rain) - Thereafter (up to 200m) = more - Then 1000m: sudden decline - Afterwards: stable - 30% (polar) - **Photic zone**: - Depth: 200m - "Salt water" density pycnocline - Isothermic zone: 34-35%, 88%, 35%, 36-37%, 40% - **Thermocline**: - Temperature decline - **Stratosphere**: 100m - (T=const.) - Depth - Appears like "orange k foot" (deer) - **Along with Equator, salinity remains high up to 550m.** - (Because of sinking of heavy water, i.e. cold) - **Then it suddenly declines in thermocline** - **Along poles, the surface water has lower salinity in summers due to ice melts, as in winters the ice freezes, causing "salt (dissolved)" excretion in water, making more saline.** - **At poles, there is seasonality (Summer: less, winters: more)** ## 6. TEMPERATURE (Oceanic) - **Heat**: Quantum of Ee - **Temperature**: Degree of hotness or coldness (it's measurable, tangible, felt on touching) - **Equatortopale temperature**: - 27°C = EQ - 23° = 20° N & 20° S - 14-15° = 40° N & 38° S (heat surplus zone) - 1-3°C = along 60° N & 60° N - 1.3-1.8°C = along polar fringes (freezing point of ocean) ## 7. TIDES - Tides refers to periodical advances (rise) and retard (fall) in sea water, which has diurnal rhythm, synchronization with the rotation of earth, with reference to the revolution of moon. - **Generated by** gravitational pull of sun or moon - **Forces Originating Tides**: Tides are the largest oscillatory motion in the ocean caused by "differential gravitational pull of sun and moon in 5:11." - **Tractive Forces** (like attractive) - Centripetal & Centrifugal force - β as of Earth's rotation - **Frictional forces** (The Coriolis forces < F - **Gravitational Force** = {m1m2)/r2 - **The laws behind the tides:** - Newton's 1st law of inertia - Newton's 3rd law ## 8. CLASSIFICATION OF TIDES: - **Daily Tides**: - **Diurnal**: - **Semi-Diurnal**: - **Monthly Tides**: - **Spring Tides**: Are higher tides with high amplitude - It occurs during the full moon and new moon.