Bio 2F03 – Lecture 5 – Friday September 13 , 2013
Life in water – chapter 3
What is different?
-density, oxygen, light, no water shortage, pressure
-water does not compress or affect animals in aquatic ecosystems
How much water is there?
-71% of Earth’s surface
`(97& ocean, 2% glaciers, 1% freshwater (1/5 Baikal (in Russia in south central Asia, 1/5 in the
great lakes, 1/5 in the rift valley lakes (in Africa, a tectonic fissure that splits Africa into east and
How deep is the ocean?
-4000m on average
Are chemical and physical conditions in the ocean similar at different latitudes?
Are chemical and physical conditions in the ocean similar at different longitudes?
-there are consistent differences
Life in water: latitude and longitude
-winds influence currents; currents bring cold or warm water
-is there any consistencies in the movement? –there’s movement towards the equator
Corealis force – water moves where there is least resistance
-water currents have an effect on the climate of regions on land
-eg. Water from Antarctica flows towards the equator to Africa and cools Africa from the
west side of Africa
Differences in longitude is because of continental differences
-differences in latitudes is due to the north and south climates
Life in water: oceanic zones
-what drives the conditions in water
-light gets absorbed by water very quickly
-there is an exponential loss of light, drop in oxygen, and temperature
-“there is a decreasing light and temperature with depth which produces a series of vertical
- drop in oxygen although the drop is reversed in greater depth because cold water contains
more oxygen which gets circulated deeper in the ocean (although amount of oxygen in water is
-open water and bottom habitats (water is bounded by land which means there would be coastal
habitats and bottom habitats which is important for the diversity of the ecosystem)
-freshwater often floats on top of salt water so the mixing of both waters is not thorough
-How many g/ L of salt in ocean salt water?
-35g/L (some areas may have less eg. In estuaries where the water may be diluted after
Zone names for oceans:
Intertidal – bottom shorezone between the lowest and the highest tide
Neritic – open on the continental shelf (depth of 50 – 200m), water on the shelf
Epipelagic – pelagic = open water, on top of th