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Ecology and Paleoecology
Fundamental Concepts of Ecology and Paleoecology
Paleoecologists are particularly interested in the marine (ocean)
ecosystem because the fossil record is dominated by
marine life.
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Ecology and Paleoecology
Fundamental Concepts of Ecology and Paleoecology
Ecology is the interrelationship between organisms and
their environment.
Paleoecology is ancient ecology.
The study of the interaction of ancient organisms with
their environment.
In large part, paleoecology depends on comparisons of
ancient organisms with living organisms.
We use modern analogs to help us interpret something
about the way in which the fossils lived and related to
their environment.
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Ecology and Paleoecology
Fundamental Concepts of Ecology and Paleoecology
Ecosystem = the organisms and their environment - the
entire system of physical, chemical, and biological
factors influencing organisms
Habitat = the environment in which the organism lives
Niche = the way in which the organism lives - its role or
lifestyle.
Community = the association of several species of organisms
in a particular habitat (the living part of the ecosystem)
Paleocommunity = an ancient community
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Trophic Levels
The organisms living in the ocean ecosystem are
commonly grouped according to their method of
obtaining nutrients, or their trophic level.
Primary Producers or autotrophs - produce their own
food through photosynthesis, and supply food
and energy for other organisms.
In the marine ecosystem, many of the autotrophs
are plankton, including tiny diatoms and other
photosynthetic organisms.
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Trophic Levels
Primary Producers or autotrophs
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Trophic Levels
Consumers or heterotrophs - cannot produce their
own food and must eat.
Herbivores - heterotrophs that eat plants
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Trophic Levels
Carnivores - heterotrophs that eat herbivores and
other carnivores
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Trophic Levels
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Trophic Levels
Decomposers and Transformers - bacteria and fungi
which break down organic matter converting
it into a form which can be utilized by other
organisms (nutrients)
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Trophic Levels
Parasites - derive nutrition from other organisms
without killing them
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Trophic Levels
Scavengers - derive nutrition from dead organisms
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The Marine Ecosystem
Pelagic Realm
Zones:
Neritic
Oceanic
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The Marine Ecosystem
Benthic Realm
Zones:
Supralittoral
Littoral
Sublittoral
Bathyal
Abyssal
Hadal
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Marine Organisms
Planktonic - small plants and animals that float, drift,
or swim weakly (plankton)
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Marine Organisms
Phytoplankton - plants and plant-like plankton, such as
diatoms and coccolithophores
silica
carbonate
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Marine Organisms
Zooplankton - animals and animal-like plankton, such as
foraminifera and radiolaria
Radiolarians
silica
Foraminifera
carbonate
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Marine Organisms
Nektonic - swimming animals that live within the water
column (nekton)
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Marine Organisms
Benthonic or benthic - bottom dwellers
Infaunal - living beneath the sediment surface;
they burrow and churn and mix the sediment, a
process called bioturbation
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Marine Organisms
Benthonic or benthic - bottom dwellers
Epifaunal - living on top of the sediment surface
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Ocean Chemistry
Nearly all water contains dissolved chemicals.
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Ocean Chemistry
These dissolved chemicals are called “salts”
Salinity is a measure of the total dissolved solids in water.
Salinity is measured in parts per thousand (ppt or o/oo)
by weight.
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Ocean Chemistry
Salinity terms for various types of water:
Normal ocean water = 35 ppt or 35 o/oo or 3.5%
A salinity of 35 ppt means that there are 35 pounds
of salt per 1000 pounds of sea water
Freshwater = about 5 ppt to less than 1 ppt
Brackish water = sea water with less than about 30 ppt
Hypersaline water = more than 250 ppt
(typically in lakes in arid areas, or in enclosed areas
like lagoons or isolated seas in arid areas)
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Ocean Chemistry
Chemical
Constituent
Percentage of Total
Salt Content
Ocean
Water
River
Water
Silica (SiO2)
--
14.51
Iron (Fe)
--
>0.74
Calcium (Ca)
1.19
16.62
Magnesium (Mg)
3.72
4.54
Sodium (Na)
30.53
6.98
Potassium (K)
1.11
2.55
Bicarbonate (HCO3)
0.42
31.90
>Sulfate (SO4)
7.67
21.41
Chloride (Cl)
55.16
8.64
Nitrate (NO3)
--
1.11
Bromide (Br)
0.20
--
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Ocean Chemistry
Many of the chemicals in sea water are essential to life
Carbon dioxide (listed as part of HCO3)
used by marine plants; amount varies with
photosynthesis
Nitrogen - used in proteins and nucleic acids
Phosphorus - a component of DNA and RNA
and molecules used in metabolism
Sulfur - used in proteins and other molecules
an energy source for Bacteria and Archaea
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Movement of Ocean Water
Waves
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Movement of Ocean Water
Waves
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Movement of Ocean Water
Surface currents
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Movement of Ocean Water
Surface currents
Currents are the unidirectional flow of water.
Surface currents are slow drifts of water set in motion
by prevailing winds.
Global current patterns are related to the pattern of
atmospheric circulation and prevailing winds.
Land masses cause currents to be deflected.
Surface currents have an affect on the climate –
transporting warm waters to northern latitudes,
for example.
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Movement of Ocean Water
Surface currents
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Movement of Ocean Water
Surface currents
Coriolis Effect
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Movement of Ocean Water
Surface currents
Currents are also affected by the Earth's rotation
through the Coriolis Effect.
Currents in the northern hemisphere tend to be
deflected toward the right (or clockwise), and
currents in the southern hemisphere tend to be
deflected to the left (or counter clockwise) as a result
of the Coriolis Effect.