the global ocean Flashcards
what % of earths surface is water
> 70%
what % of Earth surface is Oceanic
~60%
what part of the water are almost all viable (energy production > respiration) communities located + what organisms dominate these
surface waters
plankton
how many oceans can we sub divide the global ocean to and what are they
5
atlantic, arctic, pacific, Indian, southern
Atlantic ocean characteristics
- Our local
- Between American + Euro/African land masses
- Mid Atlantic ridge
- Full latitudinal ocean
- Characterised by two distinct basins
- Eels known to breed in North Atlantic basin
Arctic ocean characteristics
- Massive light/dark variation – cause ice to melt / form
- Ice coverage - major element in ocean circulation
- Things are changing…
Pacific ocean characteristics
- Largest single water mass on planet
- Northern + southern circular currents
- Various tectonic features – the ring of fire
Indian ocean characteristics
- Several tectonic features crisscross the basin
- Major atolls include Maldives and Chagos islands
- No northern element
- Increased control of land weather conditions on water movement
Southern ocean characteristics
- Circles the Antarctic continent reaching the southern tip of other continents
- No longitudinal boundaries
- Constant, unblocked circular current – no land to block wind – get really high waves
definition of seas
sub sections of oceans - usually enclosed to some extent by land
- generally on the continental shelf and have strong interactions with inputs coming from the land
why is the Mediterranean sea warm + salty
close to africa + a lot of the water evaporates off
what are the 6 main seas
Black sea
North Sea
Baltic Sea
Caribbean sea
Red sea
Dead Sea
Black sea characteristics
- An almost completely landlocked sea
- Water movement only through the Bosporus in Istanbul
- Deep anoxic water underlying warm surface waters
- Major fresh water input through the Danube
- Sea of Azov rapidly disappearing due to extraction and climate change
North Sea characteristics
- Semi open shallow sea with two major routes to the wider Atlantic
- Major riverine inflows from the UK and continental Europe
- One of the busiest shipping areas in the world
Baltic sea characteristics
- Low salinity sea enclosed by land
- Water transfer through the Skagerrak, water flow mainly out of the Baltic into the North Sea
- In many ways an extremely large estuary
Carribean sea characterstics
- A shallow, equatorial sea
- Open to the wider Atlantic
- Generally low suspended sediment load, allows growth of coral species
- Thought to be the impact site of the asteroid which resulted in the extinction of the dinosaurs
Red Sea characteristics
- A narrow sea between the African + Asian continents
- Variable depth, with large shallow areas
- Very little riverine input - clear waters
- Diverse coral reefs
- Major input of nutrients is through deposition of dust from bordering deserts
Dead Sea characteristics
- hypersaline lake
- Input is through the Jordan river
- No outflow from the Sea
- Salinity is ~10 times open sea - Density of water much higher than elsewhere – things float better
- Very little life
5 layers of the ocean
- epipelagic
- mesopelagic
- bathypelagic
- abyssalpelgaic
- hadopelagic
neritic meaning
live at shallow water near coast
pelagic meaning
live in open waters away from sea bed an shore
what are the 3 ocean zones by light
- euphotic zone (sea level): receives sunlight - barely penetrates below this zone
- dysphotic zone (200m): decreased sunlight - photosynthesis not possible
- aphotic zone (1000m+): complete darkness - includes bathypelagic zone onwards
coastal influence of ocean zones
- Most of the oceans are ones with no clear bottom – tend to be the regions where any sort of input from land is fairly minimal
what determine nutrients of ocean zones
- water movements on the surface from different directions
- water movement from the deep water coming upwards which brings nutrients with it
