Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth...
-
Upload
emil-shepherd -
Category
Documents
-
view
214 -
download
1
Transcript of Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth...
![Page 1: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/1.jpg)
Vertical profiles of elements come in a few flavors
• Increasing with depth• Decreasing with depth• Constant
These correspond to the removal processes
• Biological removal• Chemical removal• Not much removal
Summary: Lecture 2
![Page 2: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/2.jpg)
The “biological pump”
Photosynthesis• Depletion of carbon and nutrients• Production of oxygen
Respiration• Depletion of oxygen• Regeneration of carbon and nutrients
![Page 3: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/3.jpg)
Insights from 2-box model
1) physical supply = biological export(from blackboard)
Ps
Pd
![Page 4: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/4.jpg)
Biological export equals Physical supply (or, What goes down must come up)
Blood Sweat and Tears
• Jazz-Rock band • 1967 – present• Famous for “Spinning Wheel”• Terrible
The First Lawof Chemical Oceanography
![Page 5: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/5.jpg)
A Deep Ocean Clock: 14C
n + 14N 14C + p
14Cinit
14C1/2=5730 yrs
Radioactive carbon created in the atmosphere enters the ocean as 14CO2.
It decays with a half-life of 5730 years, providing a “clock” for the flow of seawater from the surface into the deep ocean.
atmosphere
ocean
“Cosmic Rays”
Ocean circulation can be timed with radioactive “tracers”.
![Page 6: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/6.jpg)
Insights from 2-box model
2) Deep Ocean residence time(from blackboard)
Radioactive Carbon
Surface ~ 6%below standard
Mean deep ocean ~ 10% below surface
(plotted relative to an arbitrary standard)
€
Δ14C =14C
14C std
−1 ⎛
⎝ ⎜
⎞
⎠ ⎟* 1000
![Page 7: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/7.jpg)
Willard Libby
•UCLA Professor of Chemistry•Inventor of radiocarbon dating•Nobel prize in 1960•Married to Leona Woods
(also famous scientist, also UCLA professor, developed first nuclear reactor)
The Second Lawof Chemical Oceanography
The deep ocean is ~1000 years “old”.
![Page 8: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/8.jpg)
Insights from 2-box model
3) Global Ocean Productivity
The elemental composition of Marine plankton
μmol/kg
0
5000
1000
dep
th
1 2 3 4
€
106CO2 +16 HNO3 +H 3PO4 + 78 H 2O
€
C106H175O42N16P +150O2
![Page 9: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/9.jpg)
Alfred Redfield
• Harvard Professor of Zoology• Discovered close relationship between plankton biomass and ocean chemistry(a.k.a. “Redfield ratios”)• Pipe smoker, bowtie wearer
Result: Carbon is exported to deep ocean at ~5x1015 g/yr
Plankton are built of elements in nearly constant proportions.
But what was Redfield made of?
The Third Lawof Chemical Oceanography
![Page 10: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/10.jpg)
Human Stoichiometry
€
106 : H 375O132C 85.7N 6.4Ca1.5P1
103 :S206Na183K177Cl127Mg40Si38.6Fe2.7Zn 2.1
100 :Cu 76I14Mn13F13Cr7Se4Mo3Co1
“The Proportions of Man”Leonardo Da Vinci
How and why are we similar to or different from phytoplankton?
Human ProportionsA chemical view
Human ProportionsA geometrical view
![Page 11: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/11.jpg)
The “biological pump”
Photosynthesis• Depletion of carbon and nutrients• Production of oxygen
Respiration• Depletion of oxygen• Regeneration of carbon and nutrients
![Page 12: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/12.jpg)
A problem with the 2-box ocean
The elemental composition of Marine plankton
(from blackboard)
O2μmol/kg
0
4000
1000
dep
th
100 200 300
![Page 13: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/13.jpg)
Insights from 2-box model
3) Global Ocean Productivity
The elemental composition of Marine plankton
μmol/kg
0
5000
1000
dep
th
1 2 3 4
€
106CO2 +16 HNO3 +H 3PO4 + 78 H 2O
€
C106H175O42N16P +150O2
![Page 14: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/14.jpg)
Introducing Horizontal Variations
To understand this, we need to study ocean circulation!
Surface Phosphate, PO4 (mmol/m3)
![Page 15: Vertical profiles of elements come in a few flavors Increasing with depth Decreasing with depth Constant These correspond to the removal processes Biological.](https://reader030.fdocuments.us/reader030/viewer/2022032703/56649f585503460f94c7d993/html5/thumbnails/15.jpg)
rivers
sedimentsf
Reviving Rivers
How many times will a P atom see the abyss?
Ps
Pd
Insights from 2-box model
4) External inputs vs. Internal recycling