final

Question 1

Describe the NPP and NEP for diff environment

Answer 1

terrestrial : medium NPP, + NEP
wetlands: high NPP, +or - NEP
aquatic: low NPP, - NEP

Question 2

Wetland biogeochem functions

Answer 2

sink, source, transformers

Question 3

oxidation reaction order

Answer 3

only nice microbes find some cold meth

Question 4

limitations of redox potentials

Answer 4

1. most redox couples not in equilibrium
2. systems continuously cycle electrons
3. redox potential is closely related to pH
4. electrode surfaces can be contaminated

Question 5

describe organic matter accumulation

Answer 5

detrital plant biomass, detritus, peat

Question 6

methanogenesis in wetlands

Answer 6

• co2 reduced to CH4 during oxidation
  -ch4 released from plant leaves

Question 7

why is sulfur redox cycling significant

Answer 7

it accounts for half or more of the total organic carbon mineralization in many environments

Question 8

physical properties of water

Answer 8

• max density at 4 C
• ice and warmer water is less dense
  -when dense water is on top, there is overturn
  -less dense on top there is stratification

Question 9

describe lake structure

Answer 9

• epilimnion
  -metalimnion (thermocline)
  -hypolimnion

Question 10

describe the epilimnion

Answer 10

warm surface waters, light energy rapidly attenuates with depth

Question 11

Metalimnion

Answer 11

zone of rapid temperature change

Question 12

hypolimnion

Answer 12

cooler, deep waters

Question 13

primary production and nutrient cycling during summer

Answer 13

there are phytoplankton, which contribute most NPP confined to surface waters
-NPP depends on external nutrients
-epilimnion is oxic so OM decomposes quickly

Question 14

fate of primary production ( photsynthetic POM)

Answer 14

dead particulate organic matter (POM) sinks into the hypolimnion where it is decomposed by microbial respiration
-decay in the hypo consumes O2 –> low redox potential
-o2 is consumed and nutrients build up

Question 15

export of POM from the epilimnion

Answer 15

• export ratio = percentage of PP that sinks to the hypo
• export ratio is 10-50% of NPP in 12 US lakes

Question 16

lake productivity is linked to nutrient concentration

Answer 16

• most lakes are P limited
  -other factors may be important
  -studies suggest co limitation

Question 17

P v N limitation

Answer 17

• natural P input to lakes is small (retention in watersheds w veg and soil; P associated with soil minerals not available)
• large amount of P is in plankton biomass- not much available
  -P recycling in the epilimnion is dominated by bacterial decomp of om

Question 18

allochthonous

Answer 18

introduced from a different area

Question 19

autochthonous

Answer 19

from that spot

Question 20

vegetation impacts soil holding capacity

Answer 20

-reduces runoff
-reduces average soil moisture content
-when removed, run off and soil water content rises

Question 21

soil porosity and texture affect runoff

Answer 21

• soil properties (porosity and texture) affect infiltration rates and soil water content
  -sands > 2mm have higher porosity than class < 0.002

Question 22

field capacity

Answer 22

water holding ability ; water content a soil can hold against the force of gravity
- is a function of porosity, water retention and presence of impermeable layers

Question 23

groundwater height =

Answer 23

stream height

Question 24

Estuaries

Answer 24

fresh (river) water to saline (ocean) water and tidal influence

Question 25

factors that determine processes on shelves

Answer 25

-presence or absence of large rivers -presence or absence of upwelling -location of ocean boundaries -shelf width

Question 26

drowned river valleys or coastal plain estuaries

Answer 26

most common - formed by sea level rise during holocene -tide and river dominated

Question 27

coastal plain, bar built estuaries

Answer 27

-longshore currents form a sand bar or sand spit across an embayment -lack a major river source -usually shallow and wind dominated

Question 28

Fjord type estuaries

Answer 28

deep, built by glaciers, shallow sill, sill might trap anoxic bottom water

Question 29

tectonically produced estuaries

Answer 29

-formed by earthquakes and block faulting -common on active coasts -creates basins that become filled with water

Question 30

estuary circulation

Answer 30

net flow is out at the surface and in along the bottom - two layered circulation

Question 31

Type A = salt wedge estuary

Answer 31

- highly stratified, river discharge dominated over tidal action -salt exchange by vertical advection across the halocline -mississippi

Question 32

Type B- Partially mixed estuary

Answer 32

- part mix, moderate stratification - tidal flow increases relative to river discharge -vertical advection and turbulence mix the system -Chesapeake bay

Question 33

Type C- well-mixed estuary

Answer 33

-vertically homogenous and well-mixed -intense tidal flow and strong turbulent mixing -lateral heterogeneity sometimes cause by strong winds -Delaware bay

Question 34

Type D- Fjord

Answer 34

sill results in stagnant bottom waters, usually highly stratified

Question 35

name the mixing proceses

Answer 35

1. advection- water mass intact but transported 2. diffusion- random scattering of water particles bc of random motions 3. dispersive mixing- scattering of water particles bc of tidal sloshing

Question 36

river and sea water ion ratios

Answer 36

1. Na/K - reflects lower affinity of marine ricks for sodium as compared to K, ocean = less effective sink for Na 2. Ca/Mg- reflects preferential removal of calcium in the ocean as biogenic calcite ( ocean more effective sink for ca)

Question 37

mixing curve for salinity

Answer 37

- in conc v salinity is linear : conservative - if non linear: non conservative

Question 38

mid estuary turbidity maxima

Answer 38

Zones of elevated suspended particulate matter (SPM) concentration at the interface between the river and the sea.

Question 39

flocculation

Answer 39

process where solids form larger clusters, or flocs, to be removed from water.