the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Synthesis Product for Ocean Time-Series (SPOTS) – A ship-based biogeochemical pilot
Nico Lange
Björn Fiedler
Marta Álvarez
Alice Benoit-Cattin
Heather Benway
Pier L. Buttigieg
Laurent Coppola
Kim Currie
Susana Flecha
Makio Honda
I. Emma Huertas
Siv K. Lauvset
Frank Muller-Karger
Arne Körtzinger
Kevin M. O'Brien
Sólveig R. Ólafsdóttir
Fernando C. Pacheco
Digna Rueda-Roa
Ingunn Skjelvan
Masahide Wakita
Angelicque White
Abstract. The presented pilot for the “Synthesis Product for Ocean Time-Series” (SPOTS) includes data from 12 fixed ship-based time-series programs. The related stations represent unique marine environments within the Atlantic Ocean, Pacific Ocean, Mediterranean Sea, Nordic Seas, and Caribbean Sea. The focus of the pilot has been placed on biogeochemical essential ocean variables: dissolved oxygen, dissolved inorganic nutrients, inorganic carbon (pH, total alkalinity, dissolved inorganic carbon, and partial pressure of CO2), particulate matter, and dissolved organic carbon. The time-series used include a variety of temporal resolutions (monthly, seasonal, or irregular), time ranges (10 – 36 years), and bottom depths (80 – 6000 m), with the oldest samples dating back to 1983 and the most recent one corresponding to 2021. Besides having been harmonized into the same format (semantics, ancillary data, units), the data were subjected to a qualitative assessment in which the applied methods were evaluated and categorized. The most recently applied methods of the time-series programs usually follow the recommendations outlined by the Bermuda Time-Series Workshop report (Lorenzoni and Benway, 2013) which is used as the main reference for “biogeochemical best-practices”. However, measurements of dissolved oxygen and pH in particular, still show room for improvement. Additional data-quality descriptors include precision and accuracy estimates, indicators for data variability, and offsets compared to a reference and widely recognized data product for the global ocean: the “GLobal Ocean Data Analysis Project”. Generally, these descriptors indicate a high level of continuity in measurement quality within time-series programs and a good consistency with the GLobal Interior Ocean Carbon Data, even though robust comparisons to the latter are limited. The data are available as (i) a merged comma-separated file that is compliant with the World Ocean Circulation Experiment (WOCE) exchange format and ii) a format dependent on user queries via the ERDDAP server of the Global Ocean Observing System (GOOS). The pilot increases the data utility, findability, accessibility, interoperability, and reusability following the FAIR philosophy, enhancing the readiness of biogeochemical time-series. It facilitates a variety of applications that benefit from the collective value of biogeochemical time-series observations and forms the basis for a sustained time-series living data product, SPOTS, complementing relevant products for the global interior ocean carbon data (GLobal Ocean Data Analysis Project), global surface ocean carbon data (Surface Ocean CO2 Atlas; SOCAT), and global interior and surface methane and nitrous oxide data (MarinE MethanE and NiTrous Oxide product).
Aside from the actual data compilation, the pilot project produced suggestions for reporting metadata, implementing quality control measures, and making estimations about uncertainty. These recommendations aim at encouraging the community to adopt more consistent and uniform practices for analysis and reporting and at updating these practices regularly. The detailed recommendations, links to the original time-series programs, the original data, their documentation, and related efforts are available on the SPOTS website. This site also provides access to the data product (DOI: 10.26008/1912/bco-dmo.896862.1, Lange et al., 2023) and ancillary data.
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Nico Lange et al.
Status: final response (author comments only)
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RC1: 'Comment on essd-2023-238', Anonymous Referee #1, 30 Aug 2023
Review of “Synthesis Product for Ocean Time-Series (SPOTS) – A ship-based biogeochemical pilot” by Nico Lange et al.
This paper provides a synthesis product for ocean biogeochemical time-series data from 12 ship-based time-series programs. Currently, we are still lacking a synthesis time-series dataset. This paper carried out a lot of data processing and the product generated by this work is valuable. More importantly, this product complements existing global ocean carbon data and is anticipated to drive increased recognition and utility of ship-based biogeochemical time-series data. Moreover, the study's recommendations for metadata reporting, quality control measures, and uncertainty estimation aim to promote more standardized and uniform practices within the scientific community, contributing to ongoing advancements in ocean research and data accessibility. I only have a few comments on this work. My major and minor are as below.
Major comments:
There are still some other time series measurements of carbonate chemistry stations such as Hawaii Ocean Time Series (HOT), Bermuda Atlantic Time Series Study (BATS), European Station for Time Series in the Ocean Canary Island, (ESTOC) and South East Asia Time Series study (SEATS). Since this paper provides carbonate chemistry data, why not incorporate the data from these stations into the study? The authors may need to consider adding these time-series dadatasetso this paper.
Table 3. The desired part is not clear to me. Authors may need to consider explaining more details about the method used for each parameter and providing appropriate references for those methods.
Minor comments
Line 135 Table 1: NO3- indicates dissolved inorganic nitrate and NO2 indicates dissolved nitrite. Please be consistent in the text.
Line 225 to 226: The Table 1 shows that K2 and KNOT started in 1999 and 1997, respectively, which is not consistent with the information in your main text Line 225 to 226.
Line 300: Typo in Lauvest and Tanhu, 2015))
Line 355 Table 3. In the variable column, is parameter referring to POC, PON, POP?
Also, carbon and nitrate. Isn’t it carbon and nitrogen? Should clarify the parameters related to particulate matter.
Line 365-385: What about salinity, particulate carbon and particulate nitrogen?
Line 372-373: Please provide more specific information about which carbon variable you are referring to DIC, DOC or POC?
Line 580-581: Why not use the estimated partial pressure of CO2 data from DIC, TA and pH measurements?
Line 808: Typo in de Boyer Montégut et al. (2004))
What does NA mean on table 4 and 5?
Citation: https://doi.org/10.5194/essd-2023-238-RC1 -
RC2: 'Comment on essd-2023-238', Anonymous Referee #2, 23 Sep 2023
Lange et al. present a well-written manuscript synthesizing biogeochemistry data of existing ocean time-series stations on a global scale. The authors have done a great job presenting the data flow and demonstrating the high quality of the compiled dataset. The manuscript is clear and nearly free of typos. The final data product will help detect changes in marine ecosystems globally and greatly benefit the entire oceanography community. I do have some minor comments and suggestions. Overall, I recommend publication with minor revisions.
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Major interpretation points
First, the authors didn’t include some other easily accessible time-series stations in the current compilation, such as BATS, OSP, and ESTOC. The data product would be more complete if the authors could add those as well. See Figure 2 in Benway et al. (2019) (https://doi.org/10.3389/fmars.2019.00393) for the locations of these stations.
Secondly, I think one aspect of future perspectives that could be emphasized more. Other BGC parameters are also routinely measured at some of the time series stations. For example, parameters such as pigments, dissolved organic nitrogen (DON), and sediment trap particles are measured at Station ALOHA. Likewise, DON, dissolved organic phosphorus, and sediment trap particles are measured at CARIACO.
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Interpretation points, by line #
Lines 135–136: Which time-series station did you use CTD rather than bottle oxygen data?
Line 272- Figure 2: Why is applying QC tests optional? Based on 3.3.1, QCs from the time-series stations are applied if they are available. To me, it seems like the authors are applying this step to all stations before the BP checks. Therefore, it's not an optional step, and the authors should consider removing "(optional)" here.
Lines 276–277: Are data from Munida and RADCOR directly obtained from the responsible PIs? If so, the authors should either state it here or in Table 1 or S1. In some cases, the data downloaded from data centers do not cover all years mentioned in Table 1. Did the authors get those missing data directly from PIs? Please clarify.
Lines 304–305: If the authors are converting the carbonate system parameters (e.g., pH) that are sensitive to temperature, it makes sense to use reported laboratory temperature for the conversion. However, for nutrients and DOC, it makes more sense to use in-situ T and S measurements for the conversion.
Lines 311–312: The conversion of POP from ug/kg to umol/kg should also be mentioned here.
Lines 313–314: If the authors look at sediment trap data at Station ALOHA which have measurements of both total PC and PIC flux, one can calculate the fraction of PIC in sinking particles. The mean fraction of all data is 10.4±4.5% using all the data. If we make the assumption that suspended particles collected by bottles have the same PIC% as sinking particles, we can easily see that the authors would overestimate the POC concentrations at Station ALOHA by ~11%. This is not a fraction that can be ignored, even at the subtropical Station ALOHA. The authors should consider labeling these data (e.g., PC as POC) with different quality flags to make users understand this caveat or incorporate this in the uncertainty analysis.
Lines 450–455: Do the authors use samples from all depths or just below 1500 db? It's a bit unclear what the authors meant by relaxing the minimum depth requirement.
Line 624: Does this high fraction also represent the natural variabilities of DOC at Station ALOHA? If it's not circulation-driven (since low variability in T and S), is it possible to be caused by biological activities? The same question can be applied to all parameters that have a higher variability than the accuracy of the method.
Lines 634–635: It would be helpful if the authors could list the names of all these stations so that we can determine where to see high natural variabilities.
Line 660: What about 33KB20020923 or 325019971101 or 49HG20010813? They seem to fall within the criteria, at least for the 2˚ spatial box, unless the minimum of 1500 m criterion is applied.
Line 955: I may have missed it. Is this point about O2 and pH discussed at all in the manuscript? If not, please add more detail.
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Editorial remarks (by line #):
Line 66: Please double-check this doi number. I cannot find this dataset using this doi.
Table 1- Variables: Why not include temperature as one of the measured properties? Some of these stations have sediment trap measurements, such as Station ALOHA, CARIACO, and BATS.
Table 1- KNOT: Data downloaded from this link is from 1992 to 2008, not 1997 to 2020. Plus, there are no direct measurements of pH reported.
Table 1-K2: Data are only from 1999 to 2008. Neither pH nor DOC values are reported.
Table 1-ALOHA: Data are from 1988 to 2016 rather than 1988 to 2019. Plus, one can download data from Station ALOHA from 1988 to the end of 2022 for the bottle data. Why do the authors only report time ranges between 1988 and 2019?
Table 1-Munida: Are data from the Munida and RADCOR not available?
Table 1-GIFT: There aren't any PO4 and DOC data available associated with the DOI.
Table 1-CVOO: The dataset is currently in review and the DOI link doesn't work now.
Table 1-Irminger Sea: The current time range is from 1983 to 2019, but there are also data available from 2020 to 2022.
Table 1-Iceland Sea: Likewise, there are also measurements from 2020 to 2022. Additionally, the earliest measurements were taken in 1985 rather than 1983.
Line 218: Replace “IS-TS” with “IC-TS”.
Line 290: Replace “fill” with “filling”.
Line 298: The citation should be Jiang et al. (2022) rather than Liqing et al. (2022). Change it throughout the manuscript.
Line 302: In Table S4, particulate matter has the unit of ug/kg in the tab "Product" and umol/kg in the tab "Time-series Stations". Be consistent and change all units to umol/kg.
Line 356- Table 3: Replace “All” with “All except silicate”.
Line 480: Replace "E.g." with "For example".
Line 565: It would be helpful to have figures like Figure 4 or 5 for all parameters in the supplemental, not just for nitrate and TA.
Lines 638 & 653: Use “Hash” rather than “Rhombus”.
Line 653 & 859: Use “Asterisk” rather than “Asterix”.
Line 654: Is it just CTD salinity or CTD oxygen? If it’s just CTD salinity, please be more specific.
Tables 4&5: Add a column of temperature.
Line 654: The authors should consider reporting the mean offset consistently either as an absolute number or a relative fraction, rather than a combination, in Table 5.
Line 654-IcelandSea: Why is there only one number in the parathesis? If it's either 3:0 or 0:3, how can the authors get 1% for the comparison?
Line 705: Suggest separating the dashed line and the text more in Figure 6.
Line 855: Consider using black-outlined empty circles for the monthly means so that observations can be better seen.
Line 860: If the fit is not significant, I don't think the authors need to put a red line fit. It will make it easier for the readers to see which relationships are significant.
Line 891: The data product is not available online yet. The authors need to post the data product before this manuscript is accepted.
Line 906: This link doesn't work. Is it supposed to be "https://data.pmel.noaa.gov/generic/erddap/tabledap/spots_bgc_ts.html"?
Line 915: This link doesn't work. Is it supposed to be "https://data.pmel.noaa.gov/generic/erddap/tabledap/spots_bgc_ts.graph"?
Citation: https://doi.org/10.5194/essd-2023-238-RC2
Nico Lange et al.
Data sets
Synthesis Product for Ocean Time Series (SPOTS) Nico Lange, Björn Fiedler, Marta Álvarez, Alice Benoit-Cattin, Heather Benway, Pier L. Buttigieg, Laurent Coppola, Kim Currie, Susana Flecha, Makio Honda, I. Emma Huertas, Siv K. Lauvset, Frank Muller-Karger, Arne Körtzinger, Kevin M. O’Brien, Sólveig R. Ólafsdóttir, Fernando C. Pacheco, Digna Rueda-Roa, Ingunn Skjelvan, Masahide Wakita, Angelicque White, Toste Tanhua https://www.bco-dmo.org/dataset/896862
Nico Lange et al.
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