THE FOSSIL RECORD Ecology and Paleoecology Fundamental Concepts of Ecology and Paleoecology Paleoecologists are particularly interested in the marine (ocean)

THE FOSSIL RECORDEcology 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.

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.

THE FOSSIL RECORDEcology and PaleoecologyFundamental 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

THE FOSSIL RECORDEcology and PaleoecologyFundamental Concepts of Ecology and Paleoecology

THE FOSSIL RECORDTrophic 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.


Primary Producers or autotrophs


Consumers or heterotrophs - cannot produce their own food and must eat.

Herbivores - heterotrophs that eat plants


Carnivores - heterotrophs that eat herbivores and other carnivores



Decomposers and Transformers - bacteria and fungi which break down organic matter converting it into a form which can be utilized by otherorganisms (nutrients)


Parasites - derive nutrition from other organisms without killing them


Scavengers - derive nutrition from dead organisms

THE FOSSIL RECORDThe Marine Ecosystem

Pelagic Realm

Zones:

Neritic

Oceanic

THE FOSSIL RECORDThe Marine Ecosystem

Benthic Realm

Zones:SupralittoralLittoralSublittoralBathyalAbyssalHadal

THE FOSSIL RECORDMarine OrganismsPlanktonic - small plants and animals that float, drift,

or swim weakly (plankton)

THE FOSSIL RECORDMarine Organisms

Phytoplankton - plants and plant-like plankton, such as diatoms and coccolithophores

carbonate

silica


Zooplankton - animals and animal-like plankton, such as foraminifera and radiolaria

Foraminiferacarbonate

Radiolarianssilica


Nektonic - swimming animals that live within the water column (nekton)

THE FOSSIL RECORDMarine OrganismsBenthonic or benthic - bottom dwellers

Infaunal - living beneath the sediment surface; they burrow and churn and mix the sediment, a process called bioturbation


Benthonic or benthic - bottom dwellersEpifaunal - living on top of the sediment surface

THE FOSSIL RECORDOcean Chemistry

Nearly all water contains dissolved chemicals.


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 )

by weight.


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)

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 --


Many of the chemicals in sea water are essential to lifeCarbon 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


THE FOSSIL RECORDMovement of Ocean Water

Waves


Waves


Surface currents


Surface currentsCurrents 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.


Surface currents


Surface currents

Coriolis Effect


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.

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THE FOSSIL RECORD Ecology and Paleoecology Fundamental Concepts of Ecology and Paleoecology Paleoecologists are particularly interested in the marine (ocean)