Discussion by disease topic

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Discussion by disease topic

• Get ready to move around!
• Form groups of 4 by disease (not usual groups) to
  work on activity
• Go to a corner of the room corresponding to the
  organism your disease affects
• Coral ? chalk board
• Marine mammals (otters, seals, etc.) ? podium
• Shellfish (shrimp, lobster, oysters, clams) ?
  back door
• Fish ?corner opposite back door
• Other ? center aisle
• Find 3 others working on same disease and find a
  place to sit

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Exploration Design a research study

• In disease-groups, break into pairs (so each gets
  a chance to talk) to compare findings
• (2 minutes)
• Reform group of 4 to work on the assignment
• Pick someone to record
• Write each persons name and each persons normal
  group (folder) name at top
• Design a research study
• Briefly describe the disease (summarize your
  homework in a few lines)
• Define the problem (knowns/unknowns about
  disease)
• Develop one testable hypothesis that would
  provide information to increase our knowledge
  about this disease
• Remember the termites Termites follow a circle
  because
• Design a method to test the hypothesis
• Predict results that would support or refute your
  hypothesis
• If the experiment shows X, that means Y is
  true. Butthen

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Origins and spread of ocean diseases

• Aquaculture (spread disease to new areas as
  animals are moved around concentrated hosts)
• Ballast water (from ships)
• Rates of spread can be very fast
• Pathogens may be able to survive in open water
• Vector-borne diseases spread by predators,
  migratory sea birds
• Transport from land via rivers to sea

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Infectious stages and host ranges

• Microorganisms can persist for very long times
  (1000s of yr) in sediment
• Environmental reservoirs
• Places pathogen can live besides the host
• Other species, sediments, soil, reef crevices
• Therefore, pathogen does not depend on host for
  survival (unlike if the only place the pathogen
  can live is in one species of host)
• Wide host ranges
• Pathogen can infect many species of host
• Outbreaks affecting endangered species
• Large population of alternate host can support
  the pathogen, which then affects the smaller,
  endangered species population

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Taxonomic diversity of hosts and pathogens in
oceans

• More different kinds of animals in oceans than on
  land
• 25/34 animal phyla live only in the ocean
• Lots of potential combinations for hosts and
  pathogens
• More kinds of organisms are parasites
• More kinds of microbes in oceans
• Modular and clonal life form common
• Low genetic diversity in hosts, slow evolution of
  resistance to pathogen

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Anthropogenic agents and pathogens

• Chemical contaminants can reduce resistance of
  organisms to pathogens
• Eutrophication (excess nutrients)
• Can increase growth rates of pathogenic microbes

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Epidemiological models

• Model way of thinking about a system
• Marine organisms have short-lived immunity
• Humans often have lifetime immunity once exposed
• Lots of unknowns

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What to do about ocean diseases?

• Vaccination, antibiotic therapy, quarantine,
  culling, development of resistant transgenics
• Ineffective or too expensive to implement
• Reduce pathogen inputs and stressors
• Pathogen inputs from land
• Pollution
• Chemicals
• Nutrients
• Mitigate climate change

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For Thursday Effects of loss of species in oceans
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Homework

• Read Kappel (2005) Losing pieces of the puzzle
  threats to marine, estuarine, and diadromous
  species
• Print out the food web diagram on the next page
  and
• 1. Use a highlighter to identify the links that
  represent relationships between see otters,
  urchins, and kelp
• 2. Draw a model that explains why kelp forests
  disappear when sea otters are removed
• 3. Use the food web to predict effect of
  decreases in sea otter populations on herbivorous
  fish/inverts abalones, sea stars, and large
  crabs. Explain predictions in writing (list
  format).
• Bring 2 copies, one to hand in, one to use in
  class. Put name and group name on paper!

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Your Name__________________________ Group
Name__________________________