THE FOSSIL RECORD

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THE FOSSIL RECORD 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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THE FOSSIL RECORD 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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THE FOSSIL RECORD 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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THE FOSSIL RECORD 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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THE FOSSIL RECORD Trophic Levels
Primary Producers or autotrophs
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THE FOSSIL RECORD Trophic Levels
Consumers or heterotrophs - cannot produce their
own food and must eat. Herbivores -
heterotrophs that eat plants
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THE FOSSIL RECORD Trophic Levels
Carnivores - heterotrophs that eat herbivores and
other carnivores
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THE FOSSIL RECORD Trophic Levels
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THE FOSSIL RECORD 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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THE FOSSIL RECORD Trophic Levels
Parasites - derive nutrition from other organisms
without killing them
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THE FOSSIL RECORD Trophic Levels
Scavengers - derive nutrition from dead organisms
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THE FOSSIL RECORD The Marine Ecosystem
Pelagic Realm Zones Neritic Oceanic
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THE FOSSIL RECORD The Marine Ecosystem
Benthic Realm Zones Supralittoral Littoral Subli
ttoral Bathyal Abyssal Hadal
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THE FOSSIL RECORD Marine Organisms
Planktonic - small plants and animals that float,
drift, or swim weakly (plankton)
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THE FOSSIL RECORD Marine Organisms
Phytoplankton - plants and plant-like plankton,
such as diatoms and coccolithophores
silica
carbonate
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THE FOSSIL RECORD Marine Organisms
Zooplankton - animals and animal-like plankton,
such as foraminifera and radiolaria
Radiolarians silica
Foraminifera carbonate
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THE FOSSIL RECORD Marine Organisms
Nektonic - swimming animals that live within the
water column (nekton)
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THE FOSSIL RECORD 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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THE FOSSIL RECORD Marine Organisms
Benthonic or benthic - bottom dwellers Epifaunal
- living on top of the sediment surface
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THE FOSSIL RECORD Ocean Chemistry
Nearly all water contains dissolved chemicals.
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THE FOSSIL RECORD 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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THE FOSSIL RECORD 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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THE FOSSIL RECORD Ocean Chemistry
Chemical Constituent Percentage of Total Salt Content Percentage of Total Salt Content
Chemical Constituent Ocean Water River Water
Silica (SiO2) -- 14.51
Iron (Fe) -- gt0.74
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
gtSulfate (SO4) 7.67 21.41
Chloride (Cl) 55.16 8.64
Nitrate (NO3) -- 1.11
Bromide (Br) 0.20 --
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THE FOSSIL RECORD 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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THE FOSSIL RECORD Movement of Ocean Water Waves
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THE FOSSIL RECORD Movement of Ocean Water Waves
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THE FOSSIL RECORD Movement of Ocean
Water Surface currents
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THE FOSSIL RECORD 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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THE FOSSIL RECORD Movement of Ocean
Water Surface currents
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THE FOSSIL RECORD Movement of Ocean
Water Surface currents Coriolis Effect
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THE FOSSIL RECORD 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.