Marine Biology and Ecology

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Marine Biology and Ecology
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Marine Biology and Ecology

• Marine biology is the study of organisms in the
  ocean, or other marine bodies of water
• Marine biology differs from marine ecology, which
  focuses on how marine organisms interact with one
  another and their environment

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Characteristics of Life

• All living organisms (marine or otherwise) share
  the following characteristics in common
• Organization
• Metabolism (the ability to transfer energy from
  their environment)
• Reproduction
• Interaction/response to their environment
• Evolutionary adaptation
• DNA

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The First Law of Thermodynamics

• Life cannot exist without energy
• Energy cannot be created or destroyed (but it can
  be transferred or transformed)
• A plant can transform light energy into chemical
  energy
• An animal can transform
  chemical energy into energy of
  movement, heat, etc.

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Primary Productivity is the synthesis of organic
materials

• Light energy from the sun is absorbed by primary
  producers (plants, algae, and certain bacteria)
  and converted into chemical energy through a
  process known as photosynthesis
• This energy is stored as organic material
  (carbohydrates, fats, proteins) and later
  released as it is used for growth, movement,
  reproduction, repair and other functions

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Photosynthesis
www.bio.miami.edu/dana226/226F08_10.html
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What kind of troph are you?

• Primary producers are known as autotrophs
  organisms that use sources of energy (sun) to
  produce their own organic matter (food)
• All other organisms are heterotrophs, which must
  obtain nourishment by consuming food from other
  organisms (autotrophs or other heterotrophs)
• Heterotrophs are consumers

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Marine Food Webs

• A food web describes who eats who and
  illustrates the transfer of energy through the
  marine ecosystem
• Very complex!
• Changes with life history (age),
  food availability, location, and
  our knowledge!

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Marine Food Webs

• Consumers can make up many levels of the food
  web, or trophic levels
• Primary consumers eat producers
• Secondary consumers eat primary consumers
• Tertiary consumers
  eat secondary
  consumers,
  and so on.

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Arrows always point to the consumer (to whom the
energy is being transferred)
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The Second Law of Thermodynamics

• The transfer of energy is never 100 efficient
  some of this energy is lost as heat
• Why you sweat while you run
• Why your car generates heat
  while it runs!

• Only 10 of the energy stored in food is
  transferred to the next trophic level
• Lost as heat, movement, metabolism

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Marine Food Webs
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The marine environment is classified into
distinct zones

• Scientists divide the marine environment into
  zones
• Primarily, these zones include pelagic (open
  water) and benthic (bottom) regions, but are
  further broken down by light, by depth, or by
  distance from shore

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The Pelagic Zone

• The pelagic zone describes the open water region
  of the oceans
• Subdivided into the neritic zone (nearshore over
  the continental shelf) and the deep water oceanic
  zone
• The pelagic community consists of organisms that
  live suspended in the water column
• They either drift (plankton) or swim (nekton)

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The Pelagic Zone

• Nekton are pelagic organisms that swim
• Plankton drift or swim very weakly, unable to
  move against a current

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Into the Deep

• The oceanic zone is further subdivided by depth
• Epipelagic zone - upper 200 meters of ocean
  includes photic zone
• Mesopelagic zone 200-1000m middle zone some
  light penetrates but insufficient for
  photosynthesis
• Bathypelagic zone 1000-4000m aphotic, cold
  (4C)
• Abyssopelagic zone 4000-6000m very deep, at or
  near the bottom

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Deep Sea Communities

• 75 of the ocean does not receive sunlight yet
  the twilight mesopelagic zone and the perpetually
  dark bathy- and abysso-pelagic zones are not
  devoid of life
• Organisms here have evolved special adaptations
  for surviving darkness, sparse food, sparse
  mates, cold temperatures, and immense pressures

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Deep Sea Communities

• Food is extremely limited in the deep ocean (no
  photosynthesis!)
• Animals here depend on food supplied from the
  photic zone via fall-out (marine snow) or the
  settling of large carcasses (fish, whales, etc)
  from above

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Deep Sea Biology

• Adaptations for deep sea organisms include
• Small body size ( lt10 inches)
• Slow metabolism sit and wait
• Watery bodies
• Extendable, hinged jaws
• Hermaphroditism
• Upward-looking eyes (or no eyes)
• Bioluminescence

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Deep Sea Organisms Dragonfish

• Small body size
• Extendable, hinged jaw
• Bioluminescent barb
• Photophores on underside
  of body
• Dark body coloration

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Deep Sea Organisms Hatchetfish

• Small body size
• Large, upward-facing eyes
• Photophores on underside
• Large, extendable mouth
• Silver body coloration

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Deep Sea Organisms Fangtooth

• Small body size
• Black

• Large, extendable jaw
• Sensory systems along body

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Deep Sea Organisms Anglerfish

• Bioluminescent angler (lure)
• Small body size
• Black body
• Extendable jaw
• Watery composition
• Parasitic sexual reproduction!

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And you thought your boyfriend was clingy

• Because mates are few and far between, the male
  anglerfish is equipped with specialized olfactory
  organs to detect and find a female
• When he does, he bites into her skin, fusing with
  the female and atrophies loses digestive system,
  brain, heart and eyes, but not gonads!

Parasitic male!
http//rmbr.nus.edu.sg/news/images/20050129-photoc
orynus_spiniceps-male_female.jpg
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Deep Sea Organisms Ctenophores

• 96 water
• Sticky (not stinging) cells for capturing food
• Bioluminescent

• Capable of capturing small prey

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The Benthic Zone

• The benthic zone includes all bottom terrain of
  the oceans
• Subdivided into
• Littoral (intertidal zone)
• Sublittoral (subtidal)
• Bathyl (includes continental slope)
• Abyssal (deep ocean floor)
• Hadal (deepest of all associated with trench
  walls and floors)

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Hydrothermal Vent Communities

• Bottom water surrounding hydrothermal vents is
  loaded with oxygen, carbon dioxide, and poisonous
  hydrogen sulfide
• No sunlight reaches this area, yet astounding
  life forms exist on and around the vent systems
• Chemosynthetic bacteria use the energy contained
  in the hydrogen sulfide to convert carbon dioxide
  into organic matter (just as solar energy is used
  in photosynthesis!)

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Hydrothermal Vent Communities

• The bacteria form the base of the food web
• Large, mouthless (and gutless!) tube worms house
  the bacteria and in return for shelter, obtain
  nourishment from the bacteria
• Large abundances of shrimp feed on the bacteria
  (primary consumers),
  while fish feed on the shrimp
  (secondary consumers) and
  so on supporting a rich food
  web

www.flickr.com/photos/aakova/6493192/
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Hydrothermal Vent Communities

• Origin of life on Earth?
• Are dead whales stepping stones for transitional
  vent communities?
• Each vent community
  hosts a unique
  assemblage of
  species!

http//www.whoi.edu/page.do?pid12458tid441cid
5709ct61article2505