View source for Software:CO2SYS

{{Infobox software
| title = CO2SYS
| author = Ernie Lewis and Doug Wallace
| released = 1998
| programming language = QBasic, MATLAB, Python, Microsoft Excel
| language = English
| website = https://cdiac.ess-dive.lbl.gov/ftp/co2sys/
https://pyco2sys.readthedocs.io/en/latest/
https://ecology.wa.gov/Research-Data/Data-resources/Models-spreadsheets/Modeling-the-environment/Models-tools-for-TMDLs
}}

'''CO2SYS''' is a family of [[Software|software]] programs that calculate [[Chemistry:Chemical equilibrium|chemical equilibria]] for [[Chemistry:Water|aquatic]] inorganic carbon species and parameters.  Their core function is to use any two of the four central inorganic carbon system parameters ([[Chemistry:PH|pH]], [[Earth:Alkalinity|alkalinity]], [[Chemistry:Dissolved inorganic carbon|dissolved inorganic carbon]], and [[Chemistry:PCO2|partial pressure of carbon dioxide]]) to calculate various chemical properties of the system.  These programs are widely used by [[Physics:Oceanography|oceanographers]] and [[Earth:Limnology|limnologists]] to understand and predict [[Chemistry:Chemical equilibrium|chemical equilibria]] in natural waters.<ref name=":0">{{Cite journal|last1=Orr|first1=J. C.|last2=Epitalon|first2=J.-M.|last3=Gattuso|first3=J.-P.|date=2015-03-09|title=Comparison of ten packages that compute ocean carbonate chemistry|url=http://pdfs.semanticscholar.org/5167/5ec70b4d26b80f537d44c54145ccc0a271a5.pdf|journal=Biogeosciences|language=en|volume=12|issue=5|pages=1483–1510|doi=10.5194/bg-12-1483-2015|bibcode=2015BGeo...12.1483O|issn=1726-4189 |doi-access=free }}</ref>

== History ==
Chemical equilibria in marine and freshwater systems were calculated according to various conventions for most of the 20th century, which led to discrepancies among laboratories' calculations and limited scientific reproducibility.<ref>{{Cite web|last=Lewis and Wallace|date=1998|title=Program Developed for CO2 System Calculations.|url=https://www.ncei.noaa.gov/access/ocean-carbon-data-system/oceans/CO2SYS/co2rprt.html|url-status=live|archive-url=https://web.archive.org/web/20210111003305/https://www.ncei.noaa.gov/access/ocean-carbon-data-system/oceans/CO2SYS/co2rprt.html |archive-date=2021-01-11 |access-date=|website=ORNL/CDIAC-105}}</ref>  CO2SYS was first published by Ernie Lewis and Doug Wallace in 1998 as a DOS-interface program written in QBasic.<ref name=":0" />  Subsequent developments have included several [[Software:MATLAB|MATLAB]] implementations,<ref name=":0" /><ref>{{Citation|last1=Van Heuven|first1=S.|title=MATLAB Program Developed for CO2 System Calculations. ORNL/CDIAC-105b.|date=2011|url=http://cdiac.ornl.gov/ftp/co2sys/CO2SYS_calc_MATLAB_v1.1/|others=Oak Ridge National Laboratory Environmental Sciences Division|publisher=Carbon Dioxide Information Analysis Center (CDIAC)|language=en|doi=10.3334/cdiac/otg.co2sys_matlab_v1.1|access-date=2021-01-09|last2=Pierrot|first2=D.|last3=Rae|first3=J.W.B.|last4=Lewis|first4=E.|last5=Wallace|first5=D.W.R.}}</ref> two [[Software:Microsoft Excel|Microsoft Excel]] templates,<ref name=":0" /><ref>Pierrot, D., Lewis, E., and Wallace, D. W. R.: MS Excel Program Developed for CO2 System Calculations, Tech. rep., Carbon Dioxide Inf. Anal. Cent., Oak Ridge Natl. Lab., US DOE, Oak Ridge, Tenn., 2006.</ref><ref>Pelletier, G., Lewis, E., and Wallace, D.: CO2SY S.XLS: A calcu- lator for the CO2 system in seawater for Microsoft Excel/VBA, Wash. State Dept. of Ecology/Brookhaven Nat. Lab., Olympia, WA/Upton, NY, USA, 2007.</ref> a [[Python (programming language)|Python]] package "PyCO2SYS",<ref>{{Citation|last1=Humphreys, Matthew P.|title=PyCO2SYS: marine carbonate system calculations in Python|date=2021-05-13|url=https://zenodo.org/record/4757055|doi=10.5281/zenodo.4757055|access-date=2021-06-14|last2=Sandborn, Daniel|last3=Gregor, Luke|last4=Pierrot, Denis|last5=van Heuven, Steven M. A. C.|last6=Lewis, Ernie R.|last7=Wallace, Douglas W. R.|journal=Zenodo |bibcode=2021zndo...4757055H }}</ref> and an [[R (programming language)|R]] package inspired by CO2SYS, "seacarb".<ref name=":0" /><ref>Gattuso, J.-P., Epitalon, J.-M. and Lavigne, H. : seacarb: seawa- ter carbonate chemistry with R. R package version 3.0.6, The Comprehensive R Archive Network, http://CRAN.R-project.org/  package=seacarb, 2015.</ref>  Development of the various CO2SYS programs continues as of 2021 with the addition of more chemical equilibrium parameters and compatibility with a wider range of environments, e.g. [[Earth:Anoxic waters|anoxic]] waters.<ref>{{Cite journal|last1=Xu|first1=Yuan-Yuan|last2=Pierrot|first2=Denis|last3=Cai|first3=Wei-Jun|date=2017|title=Ocean carbonate system computation for anoxic waters using an updated CO2SYS program|url=https://linkinghub.elsevier.com/retrieve/pii/S0304420316302481|journal=Marine Chemistry|language=en|volume=195|pages=90–93|doi=10.1016/j.marchem.2017.07.002|bibcode=2017MarCh.195...90X |via=|doi-access=free}}</ref>

== Chemical Overview ==
The aquatic inorganic carbon system is composed of the various ionic, dissolved, solid, and/or gaseous forms of carbon dioxide in water.  These species include [[Chemistry:Carbon dioxide|dissolved carbon dioxide]], [[Chemistry:Carbonic acid|carbonic acid]], [[Chemistry:Bicarbonate|bicarbonate]] anion, [[Chemistry:Carbonate|carbonate anion]], [[Chemistry:Calcium carbonate|calcium carbonate]], [[Chemistry:Magnesium carbonate|magnesium carbonate]], and others.  The relative amounts of each species in a body of water depends on physical variables including temperature and salinity, as well as chemical variables like pH and gas partial pressure.  Variables like alkalinity and dissolved (or total) inorganic carbon further define a mass and charge balance that constrains the total state of the system.<ref>{{Cite book|last=Zeebe, Richard E.|url=https://www.worldcat.org/oclc/246683387|title=CO2 in seawater: equilibrium, kinetics, isotopes|publisher=|others=Wolf-Gladrow, Dieter A.|date=15 October 2001|isbn=978-0-08-052922-6|location=Amsterdam|pages=|oclc=246683387}}</ref><ref name=":1">{{Cite book|last=Stumm, Werner.|url=https://www.worldcat.org/oclc/830169758|title=Aquatic Chemistry : Chemical Equilibria and Rates in Natural Waters.|date=2012|publisher=Wiley|others=Morgan, James J.|isbn=978-1-118-59148-2|edition=3rd|location=Hoboken|oclc=830169758}}</ref>

Given any two of the four central inorganic carbon system parameters (pH, alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide) the remainder may be derived by solving a system of equations that adhere to the principles of [[Chemistry:Chemical thermodynamics|chemical thermodynamics]].<ref name=":1" />

== References ==

{{reflist}}

[[Category:Chemistry software]]

{{Sourceattribution|CO2SYS}}