Download Unit 8 Marine Life and Environment Notes

Marine Life and the Marine
Environment.
Marine Life/Environment.
• Marine Biologists have identified over 250,000
oceanic species. This number increases every
year.
• Most marine life lives in shallow water near
shore.
• Sunlight is the key to life. (I.E. shallow water).
Marine Life/Environment.
• I. Defining and Classifying Life.
– A. Defining life.
1. Living things can capture store
and transmit energy.
2. They are capable of
reproduction.
3. They can adapt to
environments.
4. They can change through time
(evolution).
Marine Life/Environment.
– B. The 3 domains of life
(Most inclusive
subdivision of life)
• 1. Bacteria – Single
celled, very small, no
nuclei, no organelles.
–a. Cyanobacteria is
an marine example.
Marine Life/Environment.
2. Archaea – Single
celled bacterial “like”
organisms that prefer
extreme
environments (eg.
Volcanic vents).
Often produce
methane and oxidize
sulfer.
Marine Life/Environment.
2. Eukarya – Often
multicellular, have
nuclei, have organelles,
often large and complex.
a. Include Plants,
Animals, Fungi and
Protista
Marine Life/Environment.
C. Domains can divided into 5 kingdoms.
1. Monera – Bacteria. Single celled, lack nuclei.
– a. Include cyanobacteria, heterotrophic bacteria and archaea.
2. Plantae – Multicellular plants (includes algae.
3. Animalia – Multicellular animals
4. Fungi – Fungus, molds and ½ of lichens. Mostly
terrestrial.
5. Protoctista – “catch-all” of organisms that do not
fit neatly into the other kingdoms. Examples
range from some types of algae to protozoans
(like amoeba).
Marine Life/Environment.
Marine Life/Environment.
• D. Kingdoms are then divided in to Phylum,
Subphylum, Class, Order, Family, Genus and finally
Species.
Marine Life/Environment.
E. Species is the most
exclusive order of
taxonomic
classification.
1. Members of a
species may interbreed
and produce fertile
and viable offspring.
Canis lupis
Marine Life/Environment
• 2. Species name is
always 2 words (the
genus and species),
in italics, first word
(the genus)
capitalized, and the
second in small
case. Eg. Homo
sapien
Carl Linnaeus
Marine Life/Environment.
II. Classifying Marine
organisms. (A.
Plankton, B.
Nekton, and C.
Benthos)
- Typically classified
by what they do and
where they live.
Marine Life/Environment.
Plankton
Nekton
Benthos
Marine Life/Environment.
A. Plankton (Floaters) –
plants and animals that
drift with ocean current.
-Do not swim, or paddle
with direction.
- Make up most of
earth’s biomass.
-Jellyfish are the largest
plankton species.
Marine Life/Environment.
1. Different types by
feeding strategy.
a. Phytoplankton –
make their own
food
(photosynthesis)
AKA autotrophic.
b. Zooplankton –
heterotrophic = eat
their food.
Marine Life/Environment.
2. Some is bacterial
=
Bacterioplankton
3. Some is viral =
Viroplankton
Marine Life/Environment.
4. Some is catagorized by life cycle.
a. Holoplankton – whole life spent as
plankton.
b. Meroplankton – Only larval stages
are plankton.
Marine Life/Environment.
5. Some categorized
by size
a. Macroplankton
– large (eg.
Jellyfish)
b. Picoplankton –
very small.
Marine Life/Environment.
B. Nekton (swimmers) –
they can swim.
- most live in shallows
near shore.
-some spend part of
life in fresh water and
another part in salt
water (salmon or eels).
Marine Life/Environment.
C. Benthos (Bottom
Dwellers)
- Much higher
concentration in shallows
- Epifauna – live on
surface of sea floor
- Infauna – live buried
in sediment at the
bottom.
- Nectobenthos – live
on the bottom but can
swim or crawl. (like crabs)
Marine Life/Environment.
-Some benthos
utilize deep water
hydrothermal vents
as energy.
Dispelled
hypothesis that
they only existed in
shallow water
(sunlight).
Marine Life/Environment.
III. How many marine species
exist?
We will not know for a very long
time.
Over two thousand new marine
species cataloged each year.
In 2000 The Census of Marine Life
(CoML) began.
-Extensive 10 year project to
assess and catalog oceanic
diversity.
Marine Life/Environment.
• Currently only 250,000 of
1,750,000 known species
are marine.
– One reason is the
difficulty of underwater
research.
– Another is the oceans
constant environment
(less evolutionary
pressure)
Marine Life/Environment.
• Of known marine species
98% live in the Benthic
Zone (bottom dwellers).
= Benthos
• 2% inhabit pelagic
environment (within the
water column) =
nekton/plankton.
Marine Life/Environment.
IV. Organisms adaptation to oceanic
conditions.
- Ocean environment is much more stable
than terrestrial environments.
- Therefore marine organisms have not
evolved complex means of adaptation to
change.
-Therefore, small changes in Temperature,
salinity etc. can be devastating.
Marine Life/Environment.
- Water provides support for marine creatures .
= Therefore animals must depend on buoyancy and
frictional resistance to sinking (I.e. swimming and floating)
=This requires special adaptations.
Marine Life/Environment.
A. Adaptations to Water Viscosity.
- Viscosity is a substance’s resistance to
flow.
= high viscosity means substance
does not flow easily (toothpaste)
= low viscosity = flows easily (water)
Marine Life/Environment.
=Viscosity is affected by temperature and
salinity.
i. As temp increases, viscosity
decreases.
ii. As salinity increases, viscosity
increases.
Marine Life/Environment.
-Therefore, very small organisms in cold or very salty water
do not require as many “extensions” to stay afloat
(Plankton).
= More extensive projections = more surface area to
volume in ratio.
= More surface area to volume = more buoyancy.
Marine Life/Environment.
-Large animals must be
streamlined to move
efficiently through more
viscous water.
Fish shape is a prime
example.
Marine Life/Environment.
B. Temperature adaptations
-Ocean temp is far more stable than
terrestrial temperatures.
=Including daily temps and seasonal
temps.
Marine Life/Environment.
-Four reasons for ocean temp stability.
1. Heat capacity of water is higher than
land.
2. Evaporation slows heating of ocean.
3. Sunlight is distributed throughout many
meters of depth in the oceans.
4. Currents, waves and tides distribute heat.
Marine Life/Environment.
-Warm vs. Cold water species.
= Warm water plankton smaller with more
projections (more ornate).
= Warm water organisms = shorter life
cycle.
=Warm water organisms = more
biodiversity, BUT less biomass.
Marine Life/Environment.
C. Salinity – Due to osmotic pressure
organisms have varying degrees of tolerance
to salinity change.
- Euryhaline – organisms that can tolerate
a range of salinity (estuaries)
- Stenohaline – organisms that tolerate
little range of salinity (open ocean)
Marine Life/Environment.
- Diffusion – movement of molecules (often
dissolved in water) from high concentration
to low concentration.
- Osmosis – movement of water from high
“free water” concentration to low “free
water” concentration across a membrane.
Marine Life/Environment.
- Isotonic solution – Solution with equal solutes
on both sides of membrane (no net movement).
Marine Life/Environment.
- Hypotonic sol. – Solution with less solutes
than inside cell or organism. (Water diffuses
into cell/organism).
Marine Life/Environment.
- Hypertonic sol.
– Sol. with
more solutes
than in cell /
organism.
(Water diffuses
out of cell /
organism).
Marine Life/Environment
Osmotic pressure – increases as the difference
in solute concentration increases.
Marine Life/Environment.
-Adaptations –
= Saltwater fish are
hypotonic to their
environment. They
drink large
amounts of water
and release salt
from gills and
through urine.
Marine Life/Environment.
= Freshwater
fish are hypertonic
to their
environment. They
do not drink water
and release large
amounts of diluted
urine.
Marine Life/Environment.
D. Dissolved Gasses – Cold water dissolves
More gas than warm water.
- High latitude oceans produce large
quantities of plankton due to high CO2 and
O2 concentrations.
- Most marine organisms utilize gills to
exchange gasses.
Marine Life/Environment
-Most marine
organisms utilize gills
to exchange gasses.
-Water enters
through mouth,
passes gills and exits
through gill slits.
Marine Life/Environment
E. Water’s high
transparency.
- Light penetrates
ocean water to 1000
meters.
- Due to transparency
predators often rely
on site.
Marine Life/Environment
-To counter predation marine organisms often
migrate vertically to remain just under light
penetration.
- Some counter-shade (dark on top light
underneath).
-Some are transparent……Jellyfish.
Marine Life/Environment
V. Main Divisions of the
Marine Environment.
-Two main divisions =
Pelagic Environment
(open sea) and
Benthic Environment
(Sea bottom).
Marine Life/Environment
-Sunlight penetration side note.
= Euphotic Zone – From surface to about
100 meters (enough light for
photosynthesis).
= Disphotic Zone – 100m through 1000m
(small but measurable light).
= Aphotic Zone – 1000m+ (No light)
Marine Life/Environment
A. Pelagic
Environment
– Divided
into neritic
and oceanic
provinces.
Marine Life/Environment
1.Neritic province ( from coast seawardwater less than 200m in depth).
-High concentration of species diversity–
biodiversity typically decreases moving from
continental margins to open sea.
- Influenced by breaking waves, tidal
movements, seasonal variations in
temperatue and salinity.
Marine Life/Environment
2. Oceanic Province –
Seaward from point
where depth exceeds
200m –
-Divided into 4
biozones (Epipelagic,
mesopelagic,
bathypelagic and
abyssopelagic zones).
Marine Life/Environment
a. Epipelagic Zone – Only zone with enough
light for photosynthesis (photic zone).
Marine Life/Environment
b. Mesopelagic Zone – Minimum light.
-Many organisms capable of
bioluminescence.
-Deep scattering layer (caused by high
concentration of plankton) located here.
Marine Life/Environment
c. Bathypelagic and
Abyssopelagic Zones –
No light.
- Most organisms blind.
- Most predatory
-Most have sharp teeth,
very large mouths and
small bodies.
Marine Life/Environment
B. Benthic Environment (Sea
Bottom) – Divided into
Supralittoral zone,
Subneritic province, and
Suboceanic province.
1. Supralittoral zone – only
emersed during tsunamies
and severe storms (spray
zone).
Marine Life/Environment
2. Subneritic Province – High tide shoreline to
200m depth.
a. Littoral zone – Between high and low tide.
b. Sublittoral zone – Low tide to 200m deep.
i. Inner sublittoral zone– area algae
remains attached to the sea floor
(about 50m depth)
ii. Outer sublittoral zone – Algae freefloating (50m to 200m depth)
Marine Life/Environment
3. Suboceanic Province – divided into bathyal,
abyssal and hadal zones.
a. Bathyal zone – 200 – 4000m depth.
b. Abyssal zone – 4000 – 6000m depth.
c. Hadal zone – 6000+m
i. Associated with deep-sea trenches.
Marine Life/Environment