Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Deployments
• Project Information
• Program Information
• Funding

Original transmitted-light imagery and processed attenuance images of sinking particles observed by autonomous Carbon Flux Explorers deployed 100-500m in the California Current Regime, during the CCE-LTER process study (P1706) between June 2 and July 1, 2017.

These data are submitted with this manuscript: Bourne et al., 2020

The expedition followed a newly formed filament of upwelled water in a region bounded by 33.5N, 123.5W and 35.2N, 120.8W.

Sample attenuance calculation. Transmitted light color images were normalized by an in-situ composite image of the clean sample stage following Bishop et al., 2016 yielding a map of fractional transmission corrected for inhomogeneities of the light source. Attenuance (ATN) values were then calculated by taking the -log10 of the normalized image. Results were saved as bmp formatted images in attenuance units where counts in each 8- bit (red, green, blue) color plane are scaled so that 100 counts = 1 attenuance unit. 

The Carbon Flux Explorer is built on a standard ARGO style float, called the Sounding Oceanographic Lagrangian Explorer (SOLO and SOLO-II). The float is the buoyancy engine for the CFE and also manages all satellite communication of data from the CFE. The top of the float has an integrated Seabird CTD system. Temperature, pressure, and salinity data are read in bursts at 10 minute intervals as the CFE is monitoring flux at depth. These data are merged with the imagery meta data.

The software package ImageJ 1.52 (IJ, National Institutes of Health) was used for particle size analysis. Fortran codes were written for secondary data processing.

From ccelter.edu:
The California Current System is a coastal upwelling biome, as found along the eastern margins of all major ocean basins. These are among the most productive ecosystems in the world ocean. The California Current Ecosystem LTER (32.9 degrees North, 120.3 degrees West) is investigating nonlinear transitions in the California Current coastal pelagic ecosystem, with particular attention to long-term forcing by a secular warming trend, the Pacific Decadal Oscillation, and El Nino in altering the structure and dynamics of the pelagic ecosystem. The California Current sustains active fisheries for a variety of finfish and marine invertebrates, modulates weather patterns and the hydrologic cycle of much of the western United States, and plays a vital role in the economy of myriad coastal communities.

LTER Data:
The California Current Ecosystem (CCE) LTER data are managed by and available directly from the CCE project data site URL shown above. If there are any datasets listed below, they are data sets that were collected at or near the CCE LTER sampling locations, and funded by NSF OCE as ancillary projects related to the CCE LTER core research themes.

NSF Award Abstract (OCE-2224726):
Coastal upwelling regions are found along the eastern boundaries of all ocean basins and are some of the most productive ecosystems in the ocean. This award is supporting the California Current Ecosystem Long Term Ecological Research (CCE LTER) site in a major upwelling biome. It leverages the 73-year California Cooperative Oceanic Fisheries Investigations (CalCOFI) program which provides essential information characterizing climate variability and change in this system. The CCE LTER addresses two over-arching questions: What are the mechanisms leading to ecological transitions in a coastal pelagic ecosystem? And what is the interplay between changing ocean climate, community structure, and ecosystem dynamics? The investigators are working towards diagnosing mechanisms of ecosystem change and developing a quantitative framework for forecasting future conditions and how these might affect the management of key living marine resources, including numerous fishes, invertebrates, marine mammals, and seabirds. They are training graduate and undergraduate students, as well as providing educational opportunities for teachers. Public programs and outreach efforts in collaboration with the Birch Aquarium at Scripps Institution of Oceanography are increasing public awareness and understanding of climate effects on coastal pelagic communities and connecting the public to cutting-edge ocean research.

This project is adding to understanding of the mechanisms underlying abrupt ecological transitions with three interrelated foci: (1) investigation of marine heatwaves and resultant multiple stressors on organisms and communities, (2) elucidation of ecological stoichiometry and the response of multiple trophic levels to altered elemental ratios of source nutrients, and (3) analysis of top-down pressures mediated by a diverse suite of organisms. It is sustaining multi-scale measurements of five core LTER variables and responses to ocean warming, increased stratification, acidification, deoxygenation, and altered nutrient stoichiometry in the Northeast Pacific. The investigators are using long-term, spatially-resolved time series at multiple spatial scales to evaluate community shifts at multiple temporal scales, with new measurements allowing interrogation at finer taxonomic levels. They are conducting in situ multi-factorial experiments (temperature, macronutrients, micronutrients, light, grazing) in combination with genomic and transcriptomic analyses. These will complement time series measurements, inform next-generation biogeochemical models, and test hypotheses related to ecological stoichiometry and marine heatwaves. The team is also using a suite of imaging techniques, molecular and morphological methods, and active and passive acoustic approaches to quantify vertical structure and cooccurrence of organisms across trophic levels and test hypotheses about top-down control of the ecosystem.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

This project is supported by continuing grants with name variations:

• LTER: Nonlinear transitions in the California Current Coastal Pelagic Ecosystem
• Ecological Transitions in the California Current Ecosystem: CCE-LTER Phase II
• LTER: CCE-LTER Phase III: Ecological Transitions in an Eastern Boundary Current Upwelling Ecosystem
• LTER: Ecosystem controls and multiple stressors in a coastal upwelling system - CCE IV

NSF Award Abstract:

Carbon sedimentation (10 Pg C/year) via the ocean biological carbon pump is important to the regulation of atmospheric CO2, yet is poorly observed in space and time due to limitations of current methodology (moorings/ships), and thus is poorly understood and consequently is poorly represented in carbon cycle simulations. Current estimates of the strength of the ocean biological carbon pump are highly uncertain. The one year project will deploy and calibrate low-cost robotic ocean-profiling current-following Carbon Flux Explorers (CFEs) which is a necessary step paving the way high frequency broad scale monitoring and prediction of carbon sedimentation in the ocean. Project scientists will work with the San Francisco Exploratorium to enhance public knowledge of the ocean carbon cycle, ocean robotics. UC Berkeley undergraduate students will be exposed to this research activity in the class-room, as laboratory assistants, and in hands-on experience at sea.

The CFEs represent the integration of an ocean profiling float-- similar to those widely deployed in the ocean as part of the ARGO program-- with the UC Berkeley / Lawrence Berkeley National Laboratory - developed Optical Sedimentation Recorder (OSR). The CFEs dive to depth and the OSR uses a camera and three modes of illumination to image particles over time as they accumulate in a sediment trap. Periodically the sample is removed and the imaging resumes. The use of transmitted, transmitted cross-polarized transmitted, and side illumination permits three modes of quantification sample loading as measured sample attenuance, sample cross-polarized photon yield, and sample reflectance. The project specifically aims to relate the three optical metrics of sample load to the amount of particulate organic carbon, particulate inorganic carbon (also known as calcium carbonate), and other biogenic particle phases. Thus, the development will demonstrate the ability of the Carbon Flux Explorer to measure the strength of carbon sedimentation in the ocean. In a one year project. Scientists at University of California, Berkeley and engineers at Lawrence Berkeley National Laboratory and Scripps Institution of Oceanography will build/modify 2 Carbon Flux Explorers to enable the collection of samples for their calibration. These and two other CFEs and a surface tethered OSR will be co-deployed during an oceanographic expedition in California coastal and offshore waters. Collected samples will be analyzed and compared with the optical metrics of sample load, collected at the same time. The project will thus meet its major goal of demonstrating that the CFEs can measure the strength of ocean carbon sedimentation as a function of depth, time, and ocean location, in a way here-to-fore impossible to achieve from ships.

NSF Award Abstract:

The PIs request funding to complete the development of the Carbon Flux Explorer (CFE), a fully autonomous and free robotic system designed to measure and relay in real time via Iridium satellite link the hourly/diurnal variations of particulate organic carbon (POC) and particulate inorganic carbon (PIC) flux at various depths in the upper kilometer of the ocean for seasons to year-long time scales. CFEs are the successful integration of the Sounding Oceanographic Lagrangian Observer (SOLO) float (developed at Scripps) and LBNL/UC Berkeley?s imaging Optical Sediment Trap (OST). The first prototype CFE was successfully tested at sea for 2 days to 800 m in June 2007.

The proposed new work will refine and challenge the CFE design with successively longer deployments in coastal and California Current waters to evaluate and address real world issues such as biofouling and animal invasions. At the same time, engineering refinements will improve power budget and solve multiple minor system issues. On-board image processing/data reduction software will be fully established. Calibration samples (POC and PIC flux) will be obtained concurrently with CFE testing using a buoy tethered twinned OST system operating at similar depths. At the end of this project, three fully developed Carbon Flux Explorers (CFEs) will be deployed (and recovered if possible) in the open ocean for at least 3-6 months in the subarctic N Pacific.

Carbon sedimentation via the bio-carbon pump of the ocean is important to the regulation of atmospheric CO2. Due to limitations of current observational methodology (moorings/ships), carbon export (or sedimentation) is poorly observed in space and time and therefore is poorly understood and parameterized in carbon cycle simulations. CFE deployments in the world?s ocean have the potential to lead to fundamentally new insights into the biology/biogeochemistry of carbon sedimentation.

Broader Impacts:

The potential benefits to society due to the proposed activities are important. These actives will help improve confidence in future carbon cycle predictions. The results could maybe a key to helping society deal with the potentially economically and environmentally hazardous consequences due to climate change. Through education, the proposed activities and technologies developed will make the ocean more accessible to the public in general. An improved understanding of the ocean by the public will help protect the ocean's environment. The real-time observations offered by the proposed activities will help bring about such an understanding and diminish the perceived remoteness of the ocean. The proposed activities will advance ocean related scientific teaching and education. The technology in development will help enliven the ocean in the classroom, moving from textbook knowledge to real-time interactions. The proposed activities will allow students to become more connected to the global environment. The technology will help educate the public in manner needed if society is to overcome the environmental problems humanity currently faces.

The Ocean Carbon and Biogeochemistry (OCB) program focuses on the ocean's role as a component of the global Earth system, bringing together research in geochemistry, ocean physics, and ecology that inform on and advance our understanding of ocean biogeochemistry. The overall program goals are to promote, plan, and coordinate collaborative, multidisciplinary research opportunities within the U.S. research community and with international partners. Important OCB-related activities currently include: the Ocean Carbon and Climate Change (OCCC) and the North American Carbon Program (NACP); U.S. contributions to IMBER, SOLAS, CARBOOCEAN; and numerous U.S. single-investigator and medium-size research projects funded by U.S. federal agencies including NASA, NOAA, and NSF.

The scientific mission of OCB is to study the evolving role of the ocean in the global carbon cycle, in the face of environmental variability and change through studies of marine biogeochemical cycles and associated ecosystems.

The overarching OCB science themes include improved understanding and prediction of: 1) oceanic uptake and release of atmospheric CO2 and other greenhouse gases and 2) environmental sensitivities of biogeochemical cycles, marine ecosystems, and interactions between the two.

The OCB Research Priorities (updated January 2012) include: ocean acidification; terrestrial/coastal carbon fluxes and exchanges; climate sensitivities of and change in ecosystem structure and associated impacts on biogeochemical cycles; mesopelagic ecological and biogeochemical interactions; benthic-pelagic feedbacks on biogeochemical cycles; ocean carbon uptake and storage; and expanding low-oxygen conditions in the coastal and open oceans.

adapted from http://www.lternet.edu/

The National Science Foundation established the LTER program in 1980 to support research on long-term ecological phenomena in the United States. The Long Term Ecological Research (LTER) Network is a collaborative effort involving more than 1800 scientists and students investigating ecological processes over long temporal and broad spatial scales. The LTER Network promotes synthesis and comparative research across sites and ecosystems and among other related national and international research programs. The LTER research sites represent diverse ecosystems with emphasis on different research themes, and cross-site communication, network publications, and research-planning activities are coordinated through the LTER Network Office.

2017 LTER research site map obtained from https://lternet.edu/site/lter-network/