Exam 1 Flashcards
Name 2 elements in very high abundance and 2 in low abundance in planet Earth
Earth is rich in Silicate (Si) and Iron (Fe), and low on Hydrogen (H) and Helium (He) and volatile elements
What is the mean oceans depth?
4000 meters
What are the earth layer from the inside to the outside?
Inner Core
Outer Core
D” Layer
Lower Mantle
Shallow Mantle
Crust and Lithosphere
Name the Top 3 Earth’s elements in abundance
Iron (Fe) 31.9%
Oxygen (O) 29.7%
Silicate (Si) 16.1%
Name top 3 elemental abundance in the Ocean
Oxygen (O)
Hydrogen (H)
Chloride (Cl)
Sodium (Na)
What is a Divergent Plate Boundary?
Is when plates diverge at mid-ocean ridges
What is a Convergent Plate Boundary?
Plates converge producing a subduction zone
What is a Transform Fault?
Plates move laterally past each other
What is a secular/unsteady trend?
Is a progressive directional change from initial condition
What is steady state cycling?
Balance between input and output rates
What is the average temperature and salinity is the world’s oceans?
- 5 degrees Celcius
- 7 ppt
True or false! The most common elements in the crustal are the most common in the solar system
FALSE
True or False! The lighter elements are more abundant that heavy elements
TRUE
What is an advantage of the Heat Capacity of water?
Prevents extreme ranges of temperature, tends to maintain uniform body temperatures
What are the components of sea salt?
Cl (55%)
Na (30.6%)
Sulfate (7.7%)
Mg (3.7%)
Ca (1.2%)
K (1.1%)
What are the so called MAJOR IONS?
Cl
Na
Mg
SO4
Ca
K
True or false! One of the most important properties of seawater is that its major components are CONSTANT
TRUE
What is a Conservative Element?
It is an element that is unreactive
What are the main two components of rivers and seawater?
Seawater = Cl and Na
Rivers = HCO3- and Ca
In a graph with the line (mixing) if you have a deviation from the straight line what does it mean? Give an example
A deviation from the line means the element is being added or removed. For example silica is higher in rivers than in oceans. In an estuary we will typically see a negative deviation from the line due to plankton uptake
How do water molecules change in the presence of ions?
The organization of the water molecules will change depending on the charge of the ions. Because of this organizations the water properties of seawater change compared to river water
What type of ion pairs are in seawater and what do they mean?
Covalent bond: not strictly and ion pair. Atoms sharing electron (strong interaction)
Contact pair: two ions closely to each other due to different charge
Solvent share: two ions of different charge sharing a water molecule between them
Solvent separated: two ions of different charge being separated by water molecules or solvent molecules
What is residence time of an element?
t = M/(dM/dt)
M = [] x amount of water in the ocean
dM/dt = [] in “river” x amount of water flowing into the ocean
What forms of solute dominate in seawater?
Bicarbonate HCO3-
Carbonate ion CO3 (2-)
Carbonic Acid H2CO3
Why is there a deep chlorophyl maximum?
Because at that depth phytoplankton produces more chlorophyl and more pigments due to the lack of light. Photoacclimation!
River input happens it what type of margins?
Passive margins
What is a convergent margin?
Coast with volvanic activity, subductive sediments, high mountains, rapid transition from continent to ocean
Where is the new crust generated?
Spreading centers or mid-ocean ridges
What is the MIXING TIME of the Oceans
1000 years
What are the two majot ions in river water?
Bicarbonate and Calcium
How does weathering occur?
We have silicate rock up in the continent that react with carbonic acid (from CO2 + H2O), and start to alter the rock. The carbonic acid kicks out the Ca ions from the rock and dissolves the rock in some degree, producing Ca ions and Silica in solution and bicarbonate, abundant in river water. Drains into the oceans from the continents all the time. Those component run into the sea and build up and in precipitated in the ocean biologically in the form of calcium carbonate and silica used for shells.
What is the reaction equation of the reaction between CO2 + H2O?
H2O + CO2 → H2CO3 → H+ + CO2-3
What is the aprox. residence time of Na and Cl?
100 million years
How can is an element is being removed fast from the system?
Its residence time is much faster than the mixing time fo the ocean
Where is runoff the highest?
In the tropics (highest precipitation)
Name 2 boundary conditions in the oceans
Hydrothermal vents and estuaries
What is the weathering reaction equation?
CaSiO3 + H2CO3 → Ca+ + Si4+ + HCO-3 → SiO2 + CaCO3
Weathering ions is rivers Depossition
The sediment input composition depends on what?
Depends on the on the geographycal region, since different regions have different rock compositions
What region of the world produces the highest amount of sediments?
The indo-pacific
When is something reduced or oxydized?
Reduced = Gains of electrons
Oxidized = Looses electrons
How many photons are needed to fix 1 molecule of C?
8 photons!
What limits photosynthesis in the Ocean?
Nutrients and Light
What is the source of electrons in photosynthesis?
WATER H2O
Describe briefly what happens during photosynthesis?
Light comes to P680, water gets split, electrons go off through the b6f complex, protons get pumped across the membrane into the lumen to make a proton gradient. The electrons come to the PS700, there is more light energy, and electrons get handed off to NADPH. The protons inside the lumen are used by ATP synthase to convert the energy in the gradient into ATP (photophosphorylation)
How many NADPH and ATPs get formed in photosynthesis?
2 NADPH + 4 ATPs
What are the other accesory pigments?
Carotenoids and Phycobiliproteins
Why are the other pigments so important?
The absorb other wavelenghts than chlorophyl
Where are those accesoty pigments?
The photoreaction systems have ANTENNA PIGMENTS to help increase the abiloty of the receptor to absorb lught energy
How do the light reactions work?
CO2 gets fixed by being reduced and added to a sugar called Ribulose-1.5-biphosphate by the enzyme RuBisCO
How many cycles are needed to produce a 6 Carbon Sugar?
6 CYCLES
Why do phytoplankton allow themselves to be limited by the capacity of the light or dark reactions?
- Making more pigments is a waste of investment if you are never going to need it
- You can only make so much RuBisCO
- Having too many pigments is dangerous if the dark reactions can’t keep up due to free O2 radicals
How can an organism increase it alpha?
Make more pigment
How can an organism increase its Pmax?
Make more RuBisCO
In a P vs. E (photosynthesis vs. light intensity) curve explain the alpha
The values of the slope are the alpha. This part of the curve is light-limited since more light means more photosynthesis. Inside the organis, this means that the light reactions are producing ATP and NADPH at a rate that the dark reactions can easily keep up
In a P vs. E (photosynthesis vs. light intensity) curve explain the Ek
Ek is the light intensity saturating point. This means the rate of photosynthesis reached a maximum limit becuase the dark reaction are working at its maximum capacity, and can’t process ATP and NADPH any faster
In a P vs. E (photosynthesis vs. light intensity) curve explain the Pmax
Pmax is the maximum rate of photosynthesis = ATP and NADPH are being consumed as they are being processed, almost at steady state
In a P vs. E (photosynthesis vs. light intensity) curve explain the photoinhibition
It happens because the light reactions were still capturing light energy and trying to process electrons, but the elctron did not have a place to go because the dark reactions were not using ATP and NADPH fast enough, and the whole system collaped. The excess of electrons formed O2 radicals, damaging the photsystems and other proteins and nucleic acids. The cell has repairing mechanisms but this mechanisms also have a maximum working capacity, if they can’t repair fast enough, photoinhibition occurs
What is an ideal solution?
In ideal solutions the solvent has an insignifficant effect on the reaction and the only interactions exhibited by the solutes are those of the reaction of interest
Why does seawater NOT have an ideal behavior?
Because major ions are exceerting forces on each other and on the reactants and products in the chemical reaction of interest
What is the ion strength of a solution?
Is the total concentration of positive and negative charges in a solution contributed by ionic solutes
What is an acid/base reaction?
I a reaction with a proton donor such as H+ and a proton acceptor such as OH-
What are non specific interactions?
Are electrostatic effects, for example oppositely charged ions will attract one another and ions of similar charge will repel each other
Why do Na and Cl only experience non specific interaction?
Na and Cl ions are completely sorrounded by water molecules. They are so well hydrated that they experience only nonspecific interactions
What is pH?
pH = -log {H+}
Activity of protons sensed by an electrode
How are ionic strength and ideal behavior related?
Ideal behavior is reached at very low ionic strength and solute concentrations.
What is the ionic strength and pH of seawater?
Ionic stength = 0.7
pH = 8.1
When is a reaction favorable, unfavorable or at equilibrium?
Delta G = O EQULIBRIUM
Delta G < 0 FAVORABLE
Delta G > 0 UNFAVORABLE
What is the activity coefficient?
In non ideal solutions the activity coefficient (gamma) is the correction factor of all the interactions between other solutes and component i
What affects the equilibrium constant of seawater Kw?
Kw is affected mostly by SO2-4 and Mg2+ which form ion pairs
H+ + SO2-4 ⇔ HSO-4
OH- + Mg2+ ⇔ MgOH+
How does pH change with photosynthesys and respiration?
pH increases wih Photosynthesis
pH decreases with Respiration
What would happen if all the salts from seawater were remove in terms if the activity of H+?
It will mean that gamma (activity coefficient) would tend to 1 and the activity will be the same as the concentration of H+
Eh is a meassure of what and what does it mean if it is positive or negative?
Eh is the voltage and can be also be expressed as the
-log{e-} = pe
If Eh is positive it means it is an exidating environment and the activity of electrons is low. If it is negative, it is a reduzing environment and the activitu of electrons in high.
In terms if Eh what is going on in the Z-Scheme?
In the Z-Scheme the electron activity is high and therefore is a reduzing environment and the Eh is negative
How do phytoplankton incorporate nitrate inside the cell?
Through active transport since the concentration of it is so low in seawater
Why does it have to be such a high concentration of nitrate inside the cell?
Because the Nitrate Reductase has a very low affinity for the substrate so they concentrations have to be high inside the cell
In a Micahaelis-Menten curve, what are Ks and Vmax?
Ks is the half-saturation concentration and Vmax is the maximum nitrate uptake. Also, Ks are often described as the affinity of the enzyme to its substrate. A lower Ks means a high affinity!
Similar to alpha depending on the amount of pigments and Pmax depending on the amount of RuBisCO, what do Ks and Vmax depend on?
Ks depends on the amount of substrate available and Vmax depends on the amount of enzyme in the system
On what type of organisms would you expect a lower Ks?
In organisms growing in low nutrient environments, because a lower Ks menas a higher affinity and therefore more uptake of nutrients.
What can an oceanic phytoplankton compared to a coastal phytoplankton to increase its uptake?
- Increase the enzyme amounts at low levels on Nitrate
- Increase the production of the same transporter, which does not increase Ks, but increases Vmax
- Increse nitrate storage inside the cell
