Marine Ecology
Marine Biology, Marine Ecology and Biological
Oceanography – only synonyms?
• Marine Biology – biological discipline; focused on the
biology and physiology of marine organisms
• Marine Ecology – ecological discipline; focused on the
interaction of organisms with their environment and
mass or energy cycles within ecosystem
• Biological Oceanography – interdisciplinary ecological
discipline; focused on the ecology of the ocean, the
interaction between organisms and their environment
and takes into account aspects of marine chemistry,
geology and physics
The Earth – A Planet of Water
• ~71% of the earth’s surface are oceans
•
• Total volume: 1370 x 106 km3
• Average depth: 3800 m
• Maximum depth: 10,924 m (Challenger
Deep in the Mariana Trench )
–
(Land: Mt Everest 8,848 m)
• The Mariana Trench is located at a convergent plate boundary.
• Here two converging lithospheric plates collide with one another.
• At this collision point, one of the plates descends into the mantle.
• At the line of contact between the two plates the downward flexure forms a
trough known as an ocean trench.
• Ocean presents 300 times space for life
than land and freshwater combined.
• All known phyla originated in the sea, and
life on earth is believed to have begun in
the ancient oceans.
• Only 2% of human food originates from
the oceans but present 20% of high quality
protein nutrition.
Major ocean basins
1. Atlantic
2. Pacific
3. Indian
4. Arctic
Other oceans,
Caribbean, Mediterranean, Black sea, Antarctic
• 2/3rd of land area is located in the Northern hemisphere.
• 80% of Southern hemisphere is covered by water.
• Tropical to cold polar region – Basic pattern of atmospheric
& oceanic circulation.
Comparison of Oceans
Ocean
Area
(106 km2)
Volume
(106 km3)
Mean Depth (m)
Maximum
Depth (m)
Pacific
181.3
714.4
3940
11022
Atlantic
94.3
337.2
3575
8605
Indian
74.1
284.6
3840
7450
Arctic
12.3
13.7
1117
4600
1349.9
3800
Total/Me 362.0
an
Zonation of the Marine Environment
Zonation of the Marine Environment
Classification of the Marine Environment
•
Classification by light
– Photic and aphotic
– Phytoplankton need light to photosynthesize
and can only thrive in the photic zone
– Zooplankton (animals) and bacteria do not
need light and inhabit the oceans down to
the deep-sea floor
• Classification by location
– Water and sea floor divided into specific
zones: benthic & pelagic
– By water depth divided into coastal, neritic,
oceanic
– Each has distinct physical and chemical
characteristics
– Each supports different organisms