Mass Balance and Our Ocean’s
Acidification
CO2
Developed in 2014 by Matthew Crane, Science Instructor, Northern Marianas College, Saipan
What is Mass Balance
• The law of conservation of mass implies that
mass can neither be created nor destroyed.1
• Within a system mass should remain constant.
• What about inputs or output to the system?
What is Mass Balance
• Mass Balance is a technique used to account
for any inputs or outputs of material to the
system.
• Mass Balance is used in many fields, including
environmental science.
Kg
What is Mass Balance
Change in storage of mass =
mass transported in - mass transported out
+ mass produced by sources - mass eliminated
by sinks2
Figuring out Mass Balance
• Can you figure out how long it will take to fill
your bathtub?
• Can you figure out how long it will take to fill
your bathtub if the plug leaks?
Figuring out Mass Balance
• Let us say that your bathtub holds 120 gallons
and that with both taps on water flows in at a
rate of 6 gallons per minute.
Change in storage of mass =
mass transported in - mass transported out
+ mass produced by sources - mass eliminated by sinks
Figuring out Mass Balance
• Let us say that your bathtub holds 120 gallons
and that with both taps on water flows in at a
rate of 6 gallons per minute.
Change in storage of mass (volume of tub) =
mass transported in (rate of input)
- mass transported out (rate of output)
Δ Volume/time = Inflow – Outflow
Figuring out Mass Balance
• Δ Volume/time = Inflow – Outflow
Time = Δ Volume
= (120 – 0 gallons)
(Inflow – Outflow)
(6-0gallons/minute)
Time =
120 = 20 minutes
6
Figuring out Mass Balance
• Δ Volume/time = Inflow – Outflow
Time = Δ Volume
= (120 – 0 gallons)
(Inflow – Outflow)
(6-1gallons/minute)
Time =
120 = 24 minutes
5
How is my tub related to ocean
acidification?
http://theluxhome.com/
Carbon Cycle
3
Carbon Cycle
• Atmospheric – 750 -> 753.3 +3.3
• Surface Ocean – 1020 -> 1020.4 +0.4
• GtC = Gigatons of carbon per year
• 2100 or 85 years from now = 34GtC
Why is Unbalance a Problem?
• Global warming deals with the raise in CO2 in
our atmosphere leading to a raise in Earth’s
temperature.
• As CO2 is absorbed by the ocean reactions
occur, which alter the pH of the water.
4
Why is Unbalance a Problem?
• Consumption of carbonate ions impedes
calcification.
David Liittschwager/National Geographic Stock
4
Why is Unbalance a Problem?
• Many marine organisms rely on calcification to
build shells or skeletons.
• Coral reefs
– Provide shelter for organisms
– Create an extremely diverse ecosystem
– Rely on calcification to make their skeletons
Why is Unbalance a Problem?
• Science shows that the pH of our ocean has
gone down by 0.1 pH since the industrial
revolution.4, 5, 6, 7
• By the end of the century this could drop a
further 0.2-0.4 pH5, 6, 7
• Important to remember is the pH scale is a
logarithmic scale, so a decrease of 0.1 is
essentially a 30% increase in acidity4
Why is Unbalance a Problem?
8
Why is Unbalance a Problem?
• This can affect coral bleaching, reproduction,
and calcification.9
• Acidification in a warming environment
compounds the issue.9
http://www.michw.com
References
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1 - Sherman, A., Sherman, S.J., Russikoff, L. 1996. Basic Concepts of Chemistry. Houghton Mifflin Company.
P. 52
2 - Ruben, K.H. 2013. Transport Phenomena. University of Hawaii Environmental Geochemistry (GG 425)
lecture. https://www.soest.hawaii.edu/krubin/GG425/Lect15.pdf
3 – NASA. 2011. The Carbon Cycle. Earth Observatory.
http://earthobservatory.nasa.gov/Features/CarbonCycle/carbon_cycle2001.pdf
4 – NOAA. What is Ocean Acidification. Pacific Marine Environmental Laboratory.
http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F
5 - Havenhand, J.N., Buttler F., Thorndyke M.C., and Williamson J.E. 2008. Near-future levels of ocean
acidification reduce fertilization success in a sea urchin. Current Biology. Vol. 18/15, pR651–R652. DOI:
http://dx.doi.org/10.10.1016/j.cub.2008.06.015
6 – Doney, S.C., Fabry, V.J., Feely, R.A., and Kleypas, J.A. 2009. Ocean Acidification:The Other CO2 Problem.
Annual Revue Marine Science. 1:169–92. DOI: 10.1146/annurev.marine.010908.163834
7 – Wootton, J.T., Pfister, C.A., and Forester, J.D. 2008. Dynamic patterns and ecological impacts of
declining ocean pH in a high-resolution multi-year dataset. Proceedings of the National Academy of
Sciences. Vol. 105/48, p18848. www.pnas.orgcgidoi10.1073pnas.0810079105
8 – NOAA. OA Observations and Data. Pacific Marine Environmental Laboratory.
http://www.pmel.noaa.gov/co2/story/OA+Observations+and+Data
9 – Anthony, K.R.N., Kline, D.I., Diaz-Pulido, G., Dove, S., and Hoegh-Guldberg, O. 2008. Ocean
acidification causes bleaching and productivity loss in coral reef builders. Proceedings of the National
Academy of Sciences. Vol. 105/45, p17442. www.pnas.orgcgidoi10.1073pnas.0804478105
10 – Holmes-Farley, R. 2008. Reefkeeping Magazine, Reef Central. http://reefkeeping.com/issues/200503/rhf/#9
Questions?
Exercise
• Obtain:
– Two trays, two tablets, 45mL solution A, and 45mL
solution B
• Label each tray, one A and the other B
• Add solution A to tray A and solution B to tray
B
• Add a tablet to each tray
• Observe for 60 minutes and note any changes.
Exercise
• The tablets contain calcium carbonate
• Solution A is seawater
• Solution B is acidic seawater (-0.3pH)
– Done by adding .5mL white vinegar to half gallon
of seawater10
Title of Module:
Mass Balance and Ocean Acidification
What did you learn?
Were you aware of this subject before this class?
YES
NO
Do you recommend that your teacher offer this
module again? YES
NO
Any further comments: