Know lot of things about Oceanography.

1. Chapter 15

2. Oceanography
Deals with the study of
world oceans using the
methods and knowledge of
biology, chemistry, physics,
and geology.
The four major oceans are
Atlantic, Pacific, Indian,
and Arctic. Pacific ocean is
considered as the largest
ocean, and has the greatest
average depth.

4. Characteristics of ocean
water:
1. Temperature. Is not
uniform, surface layer has
warm temperature, next
layer is thermocline which
has rapid temperature
change. And the last layer
is the deep water where
temperature decreases
slowly as depth increases.

5. 2. Salinity. Refers to the
proportion of dissolved
salts to pure water and is
expressed in parts per
thousand (‰). Average
salinity in the open ocean
ranges from 35‰ to 37‰.
Principal elements of
ocean salinity; Chlorine
and sodium. Primary
sources of ocean salinity;
chemical weathering of
rocks and outgassing.
Salinity changes with
increasing depth, surface
zone has the higher
salinity.

6. Halocline, is the layer
that is characterized by
rapid decreasing salinity.
Ocean floor topography
Echo sounders and
Multibeam sonars are
devices that can
determine the depth of
the ocean through sonic
signals that bounce off the
ocean floor. Mapping can
also be done by using
satellite.

7. 1. Continental margin. Is
the zone of the ocean
floor that separates the
thin oceanic crust from
the thick continental
crust.
2. Passive continental
margin. Is characterized
by a firm connection
between continental and
oceanic crust. There is a
little volcanic activity
occurring in this
boundary. Contains
continental shelf,
continental slope, and
continental rise.

8. 3. Submarine canyons. Are
deep, steep-sided valleys
that originate on the
continental slope.
4. Active continental margin.
Is the subduction of an
oceanic lithospheric plate
beneath a continental plate.
Has a narrow continental
shelf which grades into a
deep-ocean trench. Located
around Pacific Ocean.
Accretionary wedge is a
body of sediments that has
been scraped off the surface
of oceanic lithosphere as it
moves downward beneath a
continent.

9. 5. Mid oceanic ridge. Is a
submarine mountain
chain that extends
through the entire ocean
basin. It is the site for
seafloor spreading.
6. Ocean basin. Lies
between the continental
margin and the mid-
oceanic ridge system.
Features found on the
ocean basin floor; deep-
ocean trenches, abyssal
plains and seamounts.

10. Ocean floor sediments
1. Terrigenous sediment.
Consists mineral grains
that were weathered
from continental rocks
and transported to the
ocean.
2. Biogenous sediment.
Consists of shells and
skeletons of marine
animals and plants.

11. 3. Hydrogenous sediment.
Includes minerals from
crystallized seawater.
Reefs
Three criteria for organizing
habitats of marine life:
Availability of light,
Distance from the shore,
and Water depth.
Reefs are wave-resistant
structures and composed of
animal skeletons
particularly corals.

12. 3 types of reef:
1. Atoll. Is formed from
corals that grow on the
flanks of sinking
volcanic islands.
2. Fringing reef. Lie
close to the shore of an
island or continent.
3. Barrier reef. Is similar
to fringing reef, except
that they are separated
from the mainland by
lagoon.

13. Importance of ocean
• in removing carbon from
the atmosphere and
providing oxygen.
• Has capacity to collect,
drive and mix water,
heat, and carbon dioxide.
• Economy of communities
• Source of biomedical
organisms

14. Geological resources in
the ocean floor
 Sources of Foods (fish &
shellfish)
 Sources of minerals
(crude oil, salt, sand,
gravel, manganese,
copper, nickel, iron,
cobalt, diamond, gold,
silver through mining.
However, mining can have
negative effect.