Who, What, When, Where, Why, and How of Marine Ecology

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Who, What, When, Where, Why, and How of Marine
Ecology

• Who studies marine-life habitat, populations, and
  interactions among organisms and the surrounding
  environment including their abiotic and biotic
  factors?
• What factors contribute to the distribution of
  marine organisms in their environment?
• When do temperature changes affect communities?
• Where is the benthic zone?
• Why are trophic pyramids important to Marine
  Ecologists?
• How are heterotrophs related to autotrophs?

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Chapter 2 Fundamentals of Ecology
Karleskint
Turner
Small
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Marine Ecology

• Marine Ecology is the scientific study of
  marine-life habitat, populations, and
  interactions among organisms and the surrounding
  environment including their
• abiotic factors - non-living physical and
  chemical factors that affect the ability of
  organisms to survive and reproduce and
• biotic factors - living things or the materials
  that directly or indirectly affect an organism in
  its environment

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Study of Ecology
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• Ecology
• from the Greek word oikos meaning home
• Environment
• biotic factors (living)
• abiotic factors (non-living)
• Habitat where an organisms lives
• Ecosystems
• composed of living organisms and their non-living
  environment

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Study of Ecology
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• The study of organisms interacting with one
  another and their environment. This entails
• biological (biotic) factors
• environmental (abiotic) factors
• the organisms behavior
• Niche an organisms environmental role
• Its job in the environment

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Homeostasis and Distribution of Marine Organisms
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• Maintaining homeostasis
• changes in external environment
• internal adjustments to maintain a stable
  internal environment
• optimal range
• For example, we have optimum temperature (98.6),
  pH, etc.
• zones of intolerance

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Characteristics of the Physical Environment that
Affect Organism Distribution
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• Organisms might be limited as to where there is
  sunlight
• For photosynthesis
• For vision
• Organisms might be limited to location by
  temperature
• ectotherms
• endotherms

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Characteristics of the Physical Environment that
Affect Organism Distribution
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• Organisms might be limited to where they can live
  by salinity
• Some can withstand higher salinity than others

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Characteristics of the Physical Environment that
Affect Organism Distribution
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• Some organisms are limited to location by
  pressure
• 760 mm Hg or 1 atmosphere at sea level
• increases 1 atmosphere for every 10 meters below
  sea level
• Deep sea animals are adapted to living at high
  pressure

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Characteristics of the Physical Environment that
Affect Organism Distribution
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• Metabolic requirements
• nutrients and limiting nutrients
• oxygen as a requirement for cell respiration
• Anaerobic organisms dont need oxygen
• aerobic organisms do need oxygen
• Excess nutrients can result in eutrophication and
  algal bloom
• Metabolic wastes
• carbon dioxide is a common byproduct of metabolism

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• As a review
• Physical characteristics of the environment will
  effect organism distribution
• Temperature
• pH
• Salinity
• Sunlight
• Pressure
• Nutrient availability (oxygen, nitrates,
  phosphates, etc)

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• Individuals
• Population group of individuals of same species
• Community different species living together
• Ecosystem community plus abiotic factors

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Populations
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• A group of the same species that occupies a
  specified area
• Geographic range
• For example, the lagoon, open ocean, deep sea,
  etc.
• Population size

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Distribution of Organisms in a Population
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• Population density (abundance)
• Dispersion
• clumped
• uniform
• random

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Changes in Population Size
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• Can occur through
• reproduction
• immigration
• death
• emigration
• Can be affected by
• survivorship
• life history
• opportunistic and equilibrium species

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Population Growth
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• Many ways a population can increase in size,
  depending on the carrying capacity of the
  environment
• exponential/logarithmic growth
• logistic growth

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Exponential growth
Logistic growth
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Communities
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• Composed of populations of different species that
  occupy one habitat at the same time
• Niche what an organism does in its environment
• fundamental niche
• What all that species could do in the environment
• realized niche
• Species are going to be limited by other species
  in the area that might have similar niches

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Communities
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• Biological environment
• competition
• may be interspecific or intraspecific
• may result in competitive exclusion
• resource partitioning allows organisms to share a
  resource
• predator-prey relationships
• balance of abundance of prey vs. predators
• keystone predators

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Communities
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• Symbiosis living together
• mutualism both organisms benefit
• commensalism one organism benefits, the other
  is nether harmed nor benefited
• parasitism one organism benefits, the other is
  harmed

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Ecosystems Basic Units of the Biosphere

• Energy flow through ecosystems
• Producers Autotrophs
• auto self, troph feed
• Convert energy from the sun and harness it into
  organic molecules that will make their way up the
  food chain
• Photosynthetic producers some bacteria, algae,
  plants
• Majority of primary producers on the planet
• Chemosynthetic producers some bacteria that
  live in hydrothermal vents
• Do not use energy from sun, instead use energy
  from inorganic molecules being released from
  hydrothermal vents at bottom of the ocean

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Ecosystems Basic Units of the Biosphere

• Consumers Heterotrophs
• hetero other, troph feed
• Different levels of consumers
• first-order consumers (herbivores)
• second- and third-order consumers (omnivores and
  carnivores)
• detrivores
• decomposers
• Food chains and food webs

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Ecosystems Basic Units of the Biosphere

• Trophic levels
• number of levels is limited because only a
  fraction of the energy at one level passes to the
  next level
• ecological efficiency
• ten percent rule
• trophic pyramids
• as energy passed on decreases, so does the number
  of organisms that can be supported

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Biogeochemical Cycles

• Hydrologic cycle
• water is lost through evaporation
• carried north and south from equator
• carried west to east within each hemisphere
• returned through precipitation and runoff

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Biogeochemical Cycles

• Carbon cycle
• Cellular respiration
• carbon released from organisms through
  respiration and decomposition
• Thats why we breathe out CO2
• Photosynthesis
• The carbon in CO2 isrecycled by photosynthetic
  producers
• carbon is used in shells, corals and skeletons as
  part of calcium carbonate
• fossil fuels, when burned, release CO2 back into
  atmosphere

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Biogeochemical Cycles

• Nitrogen cycle
• fixation of atmospheric nitrogen by
  microorganisms that have symbiotic relationship
  with plants
• Producers (plants) use nitrogen to synthesize
  amino acids to form proteins
• Other organisms eat those producers, to form
  their own proteins, nitrogen makes its way up
  the food chain
• bacteria recycle nitrogen from wastes and
  decomposing, dead organisms

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Biosphere

• Includes all of earths communities and
  ecosystems
• Examples of ecosystems
• estuaries
• salt marshes
• mangrove swamps
• rocky and sandy shores
• kelp forests
• coral reefs
• open ocean

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Distribution of Marine Communities

• Pelagic division
• Zones according to location to land
• neritic zone (nearshore) and pelagic zone (open
  ocean)
• Zones according to light penetration
• photic zone (light), disphotic zone (little
  light), and aphotic zone (no light, majority of
  the ocean)
• Majority of the biomass of ocean is in photic
  zone
• Organisms that live in the pelagic
• Plankton (organisms that float) and nekton
  (organisms that swim)
• Benthic division
• Bottom sediment area
• shelf zone, bathyal zone, abyssal zone, and hadal
  zone
• Organisms that live in the benthic zone are
  divided into
• Epifauna (organisms that live on top of sediment)
  and infauna (organisms that live in the sediment)

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