Skip to content

Central California Carbon, pH, and O2 (C3PO) Expedition

Processing samples in the lab.

Central California Carbon, pH, and O2 (C3PO) Expedition

Eric Fitzgerald and Jacki Long recovering the CTD rosette on the R/V Western Flyer
MBARI Expedition #469

Expedition goals: The main objectives of this research expedition are: 1) fill observational gaps for carbon dioxide (CO2) chemistry along the Central California Coast to develop calibration routines for pH sensors on underwater gliders in this region; 2) determine the rate of acidification along this region of the coast over the past decade; 3) test the Digi-DIC, a new chemical analyzer for total CO2, developed in the chemical sensor lab at MBARI. This weeklong expedition will conduct three transects going 250 kilometers (155 miles) offshore, spanning from Monterey Bay to Point Conception.

Expedition dates: July 23- 29, 2019

Ship: R/V Western Flyer

Research technology: CTD rosette, Spray underwater glider with Deep-Sea-Durafet pH sensor, Digi-DIC chemical analyzer

Expedition chief scientist: Yui Takeshita

The California coast is a hotspot for ocean acidification and hypoxia (low oxygen). This is because upwelling brings deep, low-oxygen and low-pH waters towards the surface. Over the last year, the Coastal Biogeochemical Sensing Group has worked to equip the Spray underwater glider with a pH sensor to better observe the acidification process along our coast. Gliders are autonomous platforms that profile down to 1,000 meters (3280 feet), and can be navigated from shore. They collect data as they rise to the surface, and then relay their data via satellite. They are particularly well suited to measure the coastal ocean. However, in order to routinely operate this new pH-technology, we need a calibration routine that can be easily implemented that does not rely on research vessels. We plan to take advantage of the fact that deep ocean waters are relatively stable and predictable, and calibrate the sensors at depth. Our goal is to determine how deep and how far offshore we need to go to conduct a reliable calibration.

Over the next six days, we will be collecting water samples down to 2,000 meters (1.25 miles) at approximately 20 stations spanning from Monterey Bay to Point Conception. Water samples will be analyzed onboard the ship, which we have equipped with our analytical instrumentation. We will also be testing prototype chemical sensors we have developed to measure total CO2. We are sailing with four students who have never been out to sea before, and we are very excited to provide them this opportunity!

About Central California Carbon, pH, and O2 (C3PO) Expedition

July 24-29, 2019 – Scientist Yui Takeshita led a cruise on the R/V Western Flyer to observe changes in ocean chemistry along the Central California Coast.