ch 8

Question 1

what are the three ways gasses can be found in the ocean

Answer 1

in gas phase in a bubble

as true solute surrounded by water molecules

trapped in solid (ice or clathrate hydrates)

Question 2

what is daltons law

Answer 2

daltons law of partial pressuers

gasses in a mixture exert partial pressures

Question 3

what is the volume of one more of gas at STP

Answer 3

22.414 L

Question 4

what are the trends of CO2 in winter versus summer

Question 5

CO2 trends in N and S hemisphere

Question 6

mean atmospheric pressure at sea level

Answer 6

1 atm

Question 7

equilibrium concentration of a gas in water

Answer 7

ingassing and outgassing are equal

K= [Asw]/[Ag]

Question 8

henrys law

Answer 8

gasses dissolve in seawater in proportion to their partial pressures

has henrys law coefficient

K ,HA

Question 9

what does K(HA) tell us

Answer 9

how many moles of gas A dissolves in 1 L of seawater at partial pressure of one atm of partial pressure A

Question 10

what do oceanographers use as thier henrys law coeficient

Answer 10

Bunsent solubility coeficient Ba

asks how many mL of gas can be dissolved per L of seawater Pa of 1 atm

Question 11

how is gas solubility affected by temperature

Answer 11

decreases with tempertaure

Question 12

how is solubility affected by salinity, why?

Answer 12

decreases with salinity

due to electrostatic forces exerted by salt ions that cause unfavourable conditions for dissolution

These forces need to be
overcome to make space for gas
between the water molecules

Question 13

NAEC

Answer 13

normal atmospheric equilibrium concentrations

Question 14

at equilibrium, seawater is _ saturated

Answer 14

100%

Question 15

what leads to deviations from equilibrium concentrations

Answer 15

physical effects

chemical/biological effects

Question 16

what gasses are effected by physical effects and which are affected by chemicall/biological effects

Answer 16

• Non-reactive gases are useful as a reference point - only affected by
  physical processes, e.g., by temperature and salinity
• Reactive gases (O2, CO2, et al.) influenced by physical processes
  plus biological and chemical processes

Question 17

what are the physical effects that cause deviations in NAEC

Answer 17

1. Bubble injection
2. Fast changing conditions (ocean or
   atmosphere)
3. Sea surface slicks or surfactants
4. Post-equilibrium temperature changes
5. Sedimentary or hydrothermal sources
6. Nonlinear effects of mixing

Question 18

explain bubble injection

Answer 18

At high winds, air
can be injected directly into the sea surface
through bubble formation

Question 19

result of bubble injection

Answer 19

causes supersaturation

Question 20

fast changing conditions

Answer 20

Also known as kinetic consideration,
occurs when environmental conditions change faster than equilibrium can
be achieved.
For example, when water masses sink before they reach equilibrium or
if pressure or temperature change dramatically

Question 21

fast changing conditions result

Answer 21

super or under saturation

Question 22

sea surface obstruction to air sea fluxes

Answer 22

slicks - slow exchange

sufactants- do opposite

sea ice- like slicks but much more- greatly slow or even blocks the
exchanges (depends how complete and how thick is the ice coverage)

Question 23

post equilibrium changes

Answer 23

Changes in the atmospheric composition of a gas
over time (e.g. increasing CO2,decreasing O2) causes water masses isolated
from the sea surface to deviate from the NAEC

Question 24

post equilibrium changes result

Answer 24

super or under saturated

Question 25

subsurface sources

Answer 25

Some gases have minor
sources related to physical phenomena in the deep ocean,
such as hydrothermal vents or release from warming
sediments

Question 26

subsurface sources result

Answer 26

super or under saturation

Question 27

what is the benifit of inert gasses

Answer 27

Inert gases are not affected by
biological processes
* So useful as tracers of
physical processes

Question 28

what kind of gasses does bubble mediated gas exchange effect

Answer 28

Bubbles-mediated gas exchange
affects low solubility gases more

Question 29

In deeper waters:
* more soluble and more-
temperature dependent gases
- are _

Answer 29

undersaturated

• they formed in high lats after
  rapid cooling -> needed more
  gas to flow in the ocean to
  reach 100% sat. -> might
  have sunk before it
  Hamme and Severinghaus 2007
  28
• less soluble gases are near equilibrium
  (reached the 100% equilibrium before sunk)
  or supersaturated

Question 30

what is the surface/ subsurface peak

Answer 30

strongest for most
temperature sensitive gases – as these get warmed
by the sun -> % of saturation increases,

Question 31

non linear effects of mixing

Answer 31

as seen
before the solubility
curve is nonlinear
(concave upward

mixing line ends up being higher than original solubility curve

Question 32

non linear effects of mixing result

Answer 32

only super saturation

Question 33

what controls O2 concentration

Answer 33

Oxygen: horizontal patterns of concentration vs. % saturation
A. Creation or destroying of O2
i. Photosynthesis (+)
ii. Remineralization (-)
B. Water mass mixing (+/-,depending on
[O2] in the other mass)
C. Exchanges with atm.:
* Bubble injection (+)
* Net flow of O2 across the sea surface:
* +/- depending on % saturation
* % saturation depends on A), B)
and changes in temperature