Ocean Acidification

To better understand ocean acidification and the effects on shellfish SCCOOS, along with AOOS, NaNOOS and CeNCOOS, partnered with the shellfish industry to test state-of-the-art carbon system instruments, such as the Burkeolator, at hatcheries and shellfish growing sites, as well as transition more affordable sensors (ACDC) to operations.


  1. Carlsbad Aquafarm, Agua Hedionda Lagoon - Burkeolator, SeapHOx unit, ACDC Gen 2  
  2. Catalina Sea Ranch, NOMAD buoy - ACDC Gen 1

Ocean Observations


  • Alkalinity (derived from Salinity)
  • O2
  • pCO2 (derived from pH and salinity-derived alkalinity)
  • pH
  • Pressure
  • Salinity
  • Temperature


  • Alkalinity
  • Aragonite (Omega)
  • Dissolved Inorganic Carbon??
  • pCO2 (every 15 seconds)
  • pH
  • Salinity
  • TCO2 (hourly)
  • Temperature


  • pCO2
  • Salinity
  • Temperature


1. Ecosystems and Fisheries

While the impacts of ocean acidification are vast, organisms that rely on the carbonate ion to build their shells such as clams, oysters, urchins, and even coral reefs are at great risk. The decreasing concentrations of the carbonate ion can make maintaining shells more difficult and increasing levels of acidity prove to be corrosive and harmful to such organisms. Another organism that faces the impact of ocean acidification is phytoplankton. Even though these organisms are microscopic, their response to changing levels in pH can have a drastic bottom-up effect on marine ecosystems. Some species of phytoplankton will thrive and others will die out due to competition and available resources. This imbalance of phytoplankton species will influence what higher trophic levels with members such as fish, will be present. This trend will continue up the food web, eventually affecting local fisheries and aquafarms.

2. Climate Variability and Change

Ocean acidification has the potential to fundamentally change the ocean, its habitats, food webs, and marine life. The NOAA Ocean Acidification Program and IOOS west coast Regional Associations are monitoring the changes in the ocean chemistry, researching potential effects on organisms and ecosystems, and understanding the socio-economic impacts of those changes.

Data Access

ERDDAP Burkolator
THREDDS Burkolator
Burkolator Dashboard 
ERDDAP SeapHOx Sensor
ACDC Dashboard 

Principal Investigator

Todd Martz, UCSD -  trmartz @ucsd.edu


Martz, T., K.L. Daly, R.H. Byrne, J.H. Stillman, and D. Turk. 2015. Technology for ocean acidification research: Needs and availability. Oceanography 28(2):40–47, https://doi.org/10.5670/oceanog.2015.30.

Martz, T., Send, U., Ohman, M. D., Takeshita, Y., Bresnahan, P., Kim, H. J., & Nam, S. 2014. Dynamic variability of biogeochemical ratios in the Southern California Current System. Geophysical Research Letters, 41(7), 2496-2501. https://doi.org/10.1002/2014GL059332

Frieder, C. A., Nam, S. H., Martz, T., & Levin, L. A. 2012. High temporal and spatial variability of dissolved oxygen and pH in a nearshore California kelp forest. Biogeosciences, 9(10), 3917-3930. https://doi.org/10.5194/bg-9-3917-2012

Hofmann, G. E., Smith, J. E., Johnson, K. S., Send, U., Levin, L. A., Micheli, F., ... & Martz, T. 2011. High-frequency dynamics of ocean pH: a multi-ecosystem comparison. PloS one, 6(12), e28983. https://doi.org/10.1371/journal.pone.0028983

Kroeker KJ, Micheli F, Gambi MC, Martz T. 2011. Divergent ecosystem responses within a benthic marine community to ocean acidification. Proceedings of the National Academy of Sciences, 108, 14515–20. https://doi.org/10.1073/pnas.1107789108