Lawrence Berkeley National Laboratory masthead A-Z Index Berkeley Lab masthead U.S. Department of Energy logo Phone Book Jobs Search
Tech Transfer
Licensing Interest Form Receive Customized Tech Alerts

In Situ Optical Sensor for Measuring Particulate Inorganic Carbon in Seawater


E.O. Lawrence Berkeley National Laboratory


Light transmitted through parallel (left) and crossed (right) polarizers by birefringent CaCO3 and two non-birefringent minerals (halite and SiO2). Only the birefringent calcite (CaCO3) allows light to pass through crossed polarizers.



The transport of biogenic carbon from the surface to deep ocean (commonly referred to as the "biological pump") plays a critical role in regulating the level of CO2 in the Earth's atmosphere. Understanding of the biological pump is severely limited because conventional, ship-based sampling methods cannot adequately capture the spatial and temporal variability of biomass and carbon species in the ocean. To advance the current state of knowledge regarding the functioning of the biological pump and its consequences for global carbon cycling, James Bishop and Christopher Guay of Berkeley Lab have designed a new optical sensor for making in situ measurements of particulate inorganic carbon (PIC) in seawater. PIC in the marine environment consists of biogenic particles of CaCO3. Berkeley Lab's new sensor is based on a distinguishing mineralogical characteristic of CaCO3 — its extreme birefringence. When viewed under a microscope in cross-polarized light, CaCO3 crystals appear to light up, and this property can be used for making in situ determinations of PIC in the oceans. The instrument will ultimately be designed to have spatial dimensions, power requirements, and data storage/telemetry capacity appropriate for long-term deployments on conventional, autonomous, oceanographic platforms, as well as on next-generation platforms. Berkeley Lab's new, in situ, optical PIC sensor will be useful as an auxiliary sensor on CTD profilers; the sensor will enable data to be collected on more extensive spatial scales than currently possible; and it will allow work to be conducted in harsh environments and remote areas otherwise impractical or impossible to access. Successful development of this technology will represent a major advance in marine carbon system monitoring and lead to a greater understanding of the biological pump and its relation to global climate change, thus improving computer-based simulations and forecasted responses to different greenhouse gas emission scenarios. This important, new technology should therefore find applications in basic earth sciences research as well as monitoring and regulatory efforts.

STATUS: U.S. Patent #7,030,981. Available for licensing



See More Enviromental Technologies
Last updated: 09/17/2009