Chapter 3 - Temperature, Salinity, Gases

Notes for Chapter 3:
Sea Temperature, Salinity and Dissolved Gases

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Case History: Pickled Herring

Featured Locality (p. 52): Gulf of Kara Bogaz, Caspian Sea

I. Water as a Medium for Life
terms: oxygen and hydrogen atoms, polarity, hydrogen bonding, viscosity,
surface tension, dissolving power, salt (NaCl)

Fun pre-quiz: How well do you know the properties of water?

Cool MathMol Module on Water

        RQ3.1 (see Fig. 3.1): Describe how each of the following properties
            of the water molecule is important for living organisms in the
            sea? a) hydrogen bonding; b) surface tension; c) dissolving power;
            d) tendency to clump; e) stickiness (viscosity); f) decreased density
            (increased volume) when ice forms

    a) Ocean Salinities
        terms: salinity, major constituents, parts per thousand (^o/oo), parts per
                billion (ppb), minor constituents, brackish

        RQ3.2: What are the top four of the 12 major constituents of sea salt?
            Even though they are measured in ppb, why are the minor
            constituents of sea salt still important to sea life?

Challenge: Prof. Salty determines that the local seawater has
15.0 ^o/oo Chloride. What is the local salinity?

If you are willing to download free Chime plug-in, check out animated versions of water and salt

    b) The Responses of Marine Organisms to Salinity
        terms: osmosis, chloride cells, salt glands (in seabirds), osmoregulators,
            osmoconformers, euryhaline, stenohaline

RQ3.3 (see Fig. 3.3): Why are fish different than most marine
animals with respect to the concentration of salts in their body?

II. Sea Temperatures and Marine Life

a) The Heat Capacity and Temperature of Water
terms: heat capacity, thermocline

b) The Responses of Marine Organisms to Temperature
terms: "cold" vs. "warm" blooded (ecto- vs. endothermy)

1) Warm bodies work faster
terms: endothermous

Featured Organism p. 63: bluefin tuna

RQ3.4: A tuna is partly endothermous. Which part and why
is this advantagous?

2) Extreme temperatures kill organisms
terms: upper thermal limit, zone of resistance, lower thermal limit

      3) Many organisms can shift their temperature tolerances in
            response to seasonal or short-term climatic shifts
         terms: acclimitization, eurythermal, stenothermal

      4) Temperature affects organisms by changing the rates of operation
            of their operation
         terms: enzymes

      5) Sea temperatures exert major control over reproduction and
            geographic distributions of organisms
         terms: upper thermal limit, zone of resistance, lower thermal limit,
                    submergence

        RQ3.5 (Fig. 3.7): If the sand crab, Emerita, occasionally colonizes
            the sandy beaches of Vancouver Island, why doesn't it persist
            there?

        Featured Organism p. 67: Sand crabs (Emerita analoga)
        Featured Organisms p. 68:
                    Atlantic seastar (Asterias forbesi)
                    Jonah crab (Cancer borealis)

6) Water temperature influences the ability of organisms to deal with
other environmental variables - and vice versa.

      7) Temperature tilts the balance of nature in ecological interactions
         terms: upper thermal limit, zone of resistance, lower thermal limit

III. Marine Organisms and Dissolved Gases
         terms: respiration, photosynthesis, O₂, CO₂, H₂S

RQ3.6: How are each of these gases important to marine organisms?
a) O₂b) CO₂ c) H₂S

   a) Dissolved Gases in Water
        Note: This section gets more technical than I will expect you
            to understand. I will do my best to briefly summarize
            important concepts in lecture.

        1) Oxygen is scarce in Water
            terms: Carbon-based biomass
        Note: Bacteria reproduce very rapidly so can quickly exhaust
        available O₂ dissolved in seawater.

2) Carbon dioxide and its derivatives are abundant in the ocean.
terms: bicarbonate

        3) Algal photosynthesis decreases water's ability to dissolve
            the skeletal hard parts of animals; animal respiration increases
            the water's dissolving power.

4) The acidity of water is buffered by the carbonate system.
terms: pH, alkaline vs. acidic

        5) Diffusion is a spontaneous movement of molecules that
            can nourish (or destroy) cells.
            terms: diffusion, osmosis

b) The Uptake of Gases by Plants
terms: rhizomes

c) The Uptake of Gases by Animals
terms: hemoglobin or hemocyanin (arthropods and molluscs only)

1) Gills, blood proteins, and moving blood assist the diffusional
uptake of oxygen by many animals.

        RQ3.7: How is a gill like a radiator? Why do blood proteins
            such as hemoglobin or hemocyanin improve the delivery
            of oxygen to cells of the body?

2) Gills make fishes vulnerable to loss of heat and loss of
water.

d) The Lethal and Stressful Effects of Low Oxygen Concentration

    e) The Special Problems and Adaptations of Diving Birds and
         Mammals
            terms: oxygen debt, diving mammal reflex

        RQ3.8: Why is a seal able to hold its breath for so long
            underwater? Why don't they get the bends as a human
            would?

In 1863 a whaler took a ride underwater caught by a sperm whale.
Is this an example of diving mammal reflex? I don't know!

    f) Coping with Hydrogen Sulfide
            terms: anoxic sediment = poison, u-shaped or blind burrows,
          hydrothermal vents and cool sulfide seeps

Featured Organism p. 77 (Fig. 3.12): ghost shrimp

        RQ3.9: How does a typical burrowing mudflat animal like a
            ghost shrimp manage to live contently only mm from toxic
            hydrogen sulfide?

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or Lecture Notes by Chapter
Back to Chapter 2 or ahead to Chapter 4