ADAPTATION
OF
PELAGIC LIFE
Lin Yuan-Shao (林元烧 ),tel,218 9433,email,yslin@xmu.edu.cn
Cao Wen-Qing (曹文清 ),tel,218 9433,email,wqcao@xmu.edu.cn
Guo Dong-Hui (郭东晖 ),tel,218 8471,email:dhguo@jingxian.xmu.edu.cn
Wu Li-Sheng (吴荔生 ),tel,218 8455,email,lisheng@jingxian.xmu.edu.cn
Fang Lv-Ping (方旅平 ),tel,218 9433,email,lpfang@xmu.edu.cn
Chapter 13
Adaptation of pelagic life
?Significance of staying afloat
?Keep buoyancy mechanism
?Movement
§ 13.1 Significance of staying afloat
? Phytoplankton,to get enough
light for photosynthesis.
? Once sinking or being carried
out of the photic zone by water
movement,in generally,they
will stop metabolism and die,
unless they can somehow get
back into the sunlit layer.
? zooplankton,they need sunlight
for their bio rhythm and their food
is in the shallow water.
Staying afloat
? To live in the water layers,organisms must stay in
the epipelagic,All epipelagic organisms face a
fundamental problem—— cells and tissue are
denser than water.
Keep buoyancy mechanism
Organisms must avoid sinking to stay in the
epipelagic,This is achieved by
? Increased resistance
? Increased buoyancy
? The floaters
? Reduced body density
Increased resistance
? Surface-to-Volume Ratio
?Organism’s shape
?Long projections or spines
§ 13.2 Increased buoyancy
? The second way that epipelagic organisms
can stay near the surface is to have special
adaptations that make them more buoyant.
Unlike adaptations that help the organism
resist sinking,buoyancy reduces the
tendency to sink.
? Store lipids,such as oils or fats
Calanus with oil sac
? Pockets of gas
Gas sac of Velella
like a sail
The floaters
? Marine biologists usually refer to the surface-
dwelling organisms as neuston.
? The most common method of doing this is to
have some sort of gas-filled structure to
provide buoyancy.
Gas sac of Velella
like a sail
Porpita porpita
Porpita mediterranea
Water strider
Reduced body density
Pteropods
Movement
Appendix
muscle
cilia and flagella