Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • BCO-DMO Processing Description
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Program Information
• Funding

Particle Fluxes
The OFP mooring and sample collection methods are provided in Conte et al. (2001). The OFP mooring uses conical Parflux sediment traps (McLane Research Laboratories, Falmouth MA, USA) having a 0.5 square meters (m2) sampling area. Traps are deployed at 500, 1,500 and 3,200 m depths and continuously collect the sinking particle flux at an approximate biweekly resolution. Trap cups are filled with deep seawater brine (41 parts per thousand (ppt)) poisoned with ultra‐trace metal purity HgCl2 (200 milligrams per liter (mg L-1)) to prevent organic matter degradation. Before deployment, trap cups are filled in a laminar flow hood with a trace metal clean brine (41 ppt), prepared from seawater collected at 3,000 m depth using trace‐metal clean Go‐Flo bottles, poisoned with ultra‐purity mercuric chloride (200 mg L-1) to arrest bacterial activity. Process and deployment blanks are collected during each deployment to assess potential contamination.

Analytical Methods
OFP sample processing: Sample processing protocols are described in Conte et al. (2001, 2003, 2019). Prior to quantitative sample splitting, >1,000 micrometer (μm) -sized material is transferred to a pre‐weighed Petri dish for photog- raphy, removal of swimmers, and dried at 55 degrees Celsius (°C) for mass determination. The remaining, <1000 µm material is split using a McLane rotary splitter (McLane Research Laboratories, Falmouth, MA, USA). Three subsamples are designated for organic analysis and one for trace elemental analysis. The remaining subsamples (60%) are recombined and fractionated into 500–1,000 μm, 125–500 μm, and <125 μm size fractions. For Hurricanes Fabian (25 Aug‐8Sep 2003) and Igor (13-28 Sep, 28 Sep - 12 Oct 2010) samples, the <125 μm fraction was divided into additional size fractions to better characterize the hurricane sediment plumes. The 63-125 μm ("fine sand") and 37-63 μm ("coarse silt") fractions were separated using stainless‐steel sieves. The 4-37 μm ("medium‐fine silt") fraction was concentrated by centrifuging 7 minutes at 1,000 rpm, and the supernatant containing the <4 μm ("clay") fraction was concentrated by centrifuging 10 minutes at 3,000 rpm (modified from Pedrosa‐Pàmies et al., 2013). We note that for these detrital carbonate sediments the standard nomenclature commonly used for these fractions is an operational definition only. The larger size fractions (>125 μm) were quantitatively photographed (described below), dried at 55°C and weighed to the nearest 0.01 mg. <125 μm size fraction was freeze‐dried and weighed. Mass flux was calculated from combined weights of all size fractions.

Carbonate analyses: Carbonate analyses were performed using a Coulometrics model 5011 coulometer (UIC Inc.) equipped with a System 140 module for inorganic carbon determination. Analytical uncertainty is <1.8% based on repeated measurements of flux material working standards. Carbonate δ13C and δ18O were analyzed using a Finnigan MAT252 mass spectrometer following the procedure of Ostermann and Curry (2000). Analytical precision was ±0.04 for δ18O and ±0.05 for δ13C based on the reproducibility of the internal WHOI Atlantis II coral standard. Bulk and isotopic analyses are made on the <125 μm size fraction and converted to total flux by assuming that the total mass composition approximates that of the <125 μm fraction which comprises most of the mass. Analytical precision was ±0.04 for δ18O and ±0.05 for δ13C based on the reproducibility of the internal WHOI Atlantis II coral standard. Bulk and isotopic analyses are made on the <125 μm size fraction and converted to total flux by assuming that the total mass composition approximates that of the <125 μm fraction which comprises most of the mass.

Organic carbon analyses: Particulate organic carbon (POC) and nitrogen (N) concentrations and stable isotopic composition were analyzed using a Europa 20‐20 CF‐IRMS interfaced with the Europa ANCA‐SL elemental analyzer. Before analysis, carbonates were removed by pre‐treatment with 4% sulfurous acid using a modified Verardo et al. (1990) method. Analytical uncertainty is <0.18% based on repeated measurements of flux material working standards.

Elemental analysis: Elemental analyses were made on the total <1,000 μm material using a fusion‐Inductively Coupled Plasma Mass Spectrometry (ICPMS) method developed for multi‐elemental analysis of flux material (Huang et al., 2007). Briefly, the dried sample (4-6 mg) is fused with high purity lithium metaborate (LiBO2) flux at 1,000°C in a dedicated combustion furnace, using a sample to LiBO2 flux ratio of 1:2.5. The fused sample bead was dissolved in 1M HNO3 for ICPMS analysis. Samples were analyzed on a Finnigan Element 2 ICPMS at the Woods Hole Oceanographic ICPMS Facility. Lithogenic concentration was estimated from Si and Al concentrations, assuming that the Al flux was carried mainly by lithogenic particles whose composition approximates that of pelagic clay sediments (25% Si and 8.4% Al, Li and Schoonmaker, 2003): [Lithogenic] = [Al] /0.084. Biogenic Si was estimated by subtracting the lithogenic Si from the total Si and converted to opal assuming an opal opal water content of SiO2·0.4H2O (Mortlock & Froelich, 1989). To assess analytical reproducibility and uncertainty over the analysis period and to allow for data intercalibration, we ran the certified standard PACS-2 (National Research Council of Canada) with each fusion group, and also periodically ran well-characterized working standards of OFP sediment trap material. 

- Imported sheet 1 from original Excel file "Hurricanes FABIAN03 and IGOR10 SUMMARY BCODMO_18Feb2026.xlsx" into the BCO-DMO system.
- Renamed columns to comply with BCO-DMO naming conventions.
- Applied find/replace to Latitude column: corrected value "31°50'" to "31 55N".
- Applied find/replace to Longitude column: corrected value "64°10" to "64 05W".
- Converted Latitude from degrees-decimal_minutes format to decimal degrees (N direction) in-place.
- Converted Longitude from degrees-decimal_minutes format to decimal degrees (W direction, resulting in negative values) in-place.
- Converted Sampling_Start_Date from "%d %b %y" format to ISO date format "%Y-%m-%d".
- Applied find/replace to Sampling_End_Date at rows 36, 45, and 54: corrected malformed value "23Nov 10" to "23 Nov 10".
- Converted Sampling_End_Date from "%d %b %y" format to ISO date format "%Y-%m-%d".
- Rounded Latitude and Longitude to a maximum of 4 decimal places.
- Saved the final file as "998301_v1_sedtrap_flux_bermuda_carbonate_platform.csv".

The Oceanic Flux Program (OFP) has continuously measured particle fluxes in the deep Sargasso Sea since 1978. The OFP is the longest running continuous time-series of its kind, and has produced a unique record of temporal variability in material transfer from the surface to the deep ocean (the “biological pump") resulting from the interplay between physical, biological and chemical processes. The OFP deploys a subsurface mooring anchored in 4500m of water with three McLane Research Parflux Mark 8 sediment traps located at 500m, 1500m and 3200m depths. These traps continuously collect the sinking particle flux at an approximate 2 week sampling resolution.

The most recent project awards and abstracts are listed below.  A detailed history of funding with summary of all project awards for OFP can be found below.

October 2024 through September 2027
NSF Award OCE-2421112 Abstract:

This award provides an additional three years of support for the Oceanic Flux Program (OFP). The OFP was established in 1978 to measure the export flux of particles from the surface to the deep ocean in the deep Sargasso Sea near Bermuda. The OFP is the longest and most continuous particle flux time-series of its kind. Through collaboration with nearby upper ocean time-series programs, facilities, and other Bermuda-based sampling programs, OFP will continue to be a valuable resource for the oceanographic community in the effort to answer questions about the intricate relationship between deep ocean particle flux and climate, as well as biological, physical, and chemical oceanographic processes. Looking to the future, OFP will use increasingly advanced instrumentation and state-of-the-art analytical tools to investigate the nature and patterns of the material that sinks from the surface to deep ocean and the mechanisms that drive that process. The OFP provides education and training for students from high school to Ph.D. levels and supports early career researchers. OFP data and samples are broadly available to other researchers across the scientific disciplines.

Two overarching goals drive core activities funded under the OFP grant. The first is to extend the time-series by collecting new samples of the highest quality, while ensuring they have a comprehensive oceanographic context. The second is to elucidate the processes that drive oceanic particle flux through comparative studies of flux magnitude and composition with concurrent observations of external forcing (e.g., synoptic scale meteorology, climate patterns), surface water physics and biology (e.g., mesoscale features, blooms), and interior processes (e.g., biological particle aggregation/disaggregation, elemental scavenging, authigenic mineralization). The specific grant objectives are: (1) to provide for continuity of the particle flux measurements at 500, 1500 and 3200 m depths and continue to refine the quality of the time-series record and expand its oceanographic context, (2) to update/calibrate OFP sample processing and analytical methods to enhance the time-series data record, and to curate the time-series sample archives for future study, (3) to promote collaborative research to maximize interdisciplinary information obtained from the samples, (4) to conduct focused studies to identify deep flux temporal trends and their coherence with upper ocean forcing, to elucidate causal flux generation processes, and to develop proxies for climate studies,
(5) to provide education and training opportunities. A particular focus of this funding cycle will be to analyze the extensive OFP digital image archive with an automated (and/or semi-automated) approach, including classical methodologies and Deep Learning (DL) based tools for image classification, segmentation and archive, and a Graphical User Interface (GUI). The development of these new tools for identification, quantification, and characterization of the flux material will better exploit the image archive's potential, as fuller characterization of biological components will contribute new information on the ecosystem dynamics and responses to environmental forcing that drive flux generation.
 

October 2023 through September 2025
NSF Award OCE-2414704 Abstract:

This award provides an additional three years of support for the Oceanic Flux Program (OFP). This program was first established in 1978 to measure the export flux of particles from the surface to the deep ocean in the deep Sargasso Sea and represents the longest and most continuous particle flux time-series of its kind. This program and the time-series record will continue to help the oceanographic community to answer questions about the relationship between deep ocean particle flux and climate and biological, physical, and chemical oceanographic processes. In the past, the OFP has provided evidence for coupling between the upper and deep ocean processes linked to seasonal, episodic (e.g., physical and meteorological forcing) and climate patterns. Looking to the future, this program will utilize increasingly advanced instrumentation and analytical tools to address questions about the material that sinks from the surface to deep ocean and its controls. The OFP provides education and training for students from the high school to Ph.D. level and supports early career researchers.

The OFP time-series represents a 43-year, nearly continuous record focused on particle fluxes in the deep ocean. With increasingly more data available from the lengthening record, investigators can put observed biogeochemical patterns into perspective to understand the interplay between climate and ocean functioning. The availability of data from complementary nearby Hydrostation S, the Bermuda Atlantic Time-Series (BATS), the Bermuda Testbed Mooring (1994-2007), the Tudor Hill atmospheric tower and other Bermuda sampling programs provide additional opportunities to study upper ocean physics and biogeochemistry coupled with deep ocean biogeochemical processes. The OFP record is becoming long enough to study deep flux linkages with gyre circulation and advective processes. The OFP's archive is an unparalleled resource for retrospective studies of temporal trends and the biogeochemical consequences of a changing ocean, including future impacts of ocean acidification. As the OFP heads into the future, increasingly sophisticated OFP mooring instrumentation (ADCP current profiling and backscatter; MicroCAT temperature, salinity, and oxygen measurements) and advances in digital imaging and analytical tools (both chemical and genomic) to probe the recovered flux materials continue to reveal novel, fundamental information about the oceanic particle flux and its controls

(Adapted from the NSF Project Summary)

Since 1978, the Oceanic Flux Program (OFP), originally founded and managed by at the Woods Hole Oceanographic Institution and now managed by the Bermuda Institute of Ocean Science (BIOS), has continuously measured particle fluxes in the deep Sargasso Sea. The 35+ year OFP time-series is, by far, the longest of its kind and unique in its focus on the deep ocean. OFP has produced a unique, albeit "edited", record of temporal variability in the "biological pump", a term loosely applied here to material transfer from the surface to the deep ocean. The OFP provided the first direct evidence for seasonality in the deep ocean and the tight coupling between deep fluxes and upper ocean processes. It has provided clear evidence of the intensity of biological reprocessing of flux and scavenging of suspended material in mesopelagic waters. The record has documented interannual and longer variations in deep fluxes and shorter term fluctuations driven by the interactions between mesoscale physical variability, meteorological forcing and ecosystem responses.