MMRV: Guiding Carbon on Its Journey from the Fast to the Slow Cycle

The ocean, a vast and dynamic carbon sink, plays a critical role in regulating Earth's climate. Within its sunlit upper layers, the "photic zone," microscopic marine life efficiently captures atmospheric carbon dioxide (CO2​) through photosynthesis, initiating what's known as the fast carbon cycle. However, for this captured carbon to contribute to long-term climate mitigation, it must be transferred to the deep ocean, where it enters the slow carbon cycle, sequestered for centuries or even millennia.

At Gigablue, our mission is to ensure this crucial transfer. We've developed a robust Marine Carbon Dioxide Removal (mCDR) strategy that meticulously guides fixed carbon from the fast cycle in the photic zone to stable sequestration below the thermocline. Central to this approach is our innovative Measurement, Monitoring, Reporting, and Verification (MMRV) method, which comprises four interconnected stages:

Gigablue's Four-Stage MMRV Framework for Ocean Carbon Sequestration:

1) Holistic Background Measurements (Pre-Activity Characterization): Before any mCDR activity commences, we conduct a comprehensive characterization of the marine environment. This initial data collection is paramount for establishing a baseline against which future changes can be accurately assessed. A key focus is the precise identification of the thermocline, the crucial boundary separating the warmer, mixed surface waters from the colder, deeper layers.

To achieve this, we deploy a Conductivity, Temperature, and Depth (CTD) instrument. This instrument meticulously profiles the water column, providing high-resolution data on temperature, salinity, and pressure with depth. This detailed understanding of the water column's physical properties, including the identification of the pycnocline (a sharp density gradient often associated with the thermocline), informs the design of our in situ measurements for subsequent stages.

CTD instrumentation

Oceanographic Echosounder

Physiochemical parameters of the water column acquired by CTD instrumentation during activity in May 2024 in the Southern Ocean.

2) Fixation Monitoring and Measurement (Carbon Capture): This stage focuses on the initial capture of carbon within the photic zone. Our MMRV process involves continuous environmental monitoring during the carbon fixation phase. Simultaneously, we employ advanced techniques to accurately measure the amount of carbon being fixed by marine organisms. This ensures we quantify the efficiency of carbon uptake in the upper ocean.

3) Sequestration and Storage (The Deep Dive): This is where the magic of long-term carbon removal emerges. Once the carbon-laden substrate transitions from its buoyant phase to a settling phase, beginning its descent through the water column. During this critical sequestration phase, we continue rigorous environmental monitoring to track its journey. For example, we deploy echosounders for continuous, real-time tracking and monitoring of the settling substrate. This allows us to verify its successful passage below the thermocline and into the deep ocean, ensuring it is effectively removed from the fast carbon cycle. In addition, we employ various methods to measure the quantity of carbon successfully sequestered in these deeper waters.

4) Impact Verification (Post-Activity Background): Following the completion of a mCDR activity, a final round of comprehensive background data collection is conducted. This post-activity assessment allows us to evaluate the long-term impact of our work and to verify the sustained sequestration of carbon. By comparing pre- and post-activity data, we can confirm the successful and durable transfer of carbon from the fast to the slow carbon cycle, fulfilling our commitment to responsible and verifiable climate action.

By rigorously implementing these four stages systematically, Gigablue's MMRV method provides a scientifically sound framework for assessing the effectiveness of our mCDR efforts and communicating them transparently. This methodical approach is fundamental to ensuring that the carbon fixed in the photic zone is indeed transferred and locked away in the slow carbon cycle, contributing meaningfully to global efforts in climate change mitigation.