the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
The Western Channel Observatory: a century of oceanographic, chemical and biological data compiled from pelagic and benthic habitats in the Western English Channel
Angus Atkinson
Ruth L. Airs
Rachel Brittain
Ian Brown
Elaine S. Fileman
Helen S. Findlay
Caroline L. McNeill
Clare Ostle
Tim J. Smyth
Paul J. Somerfield
Karen Tait
Glen A. Tarran
Simon Thomas
Claire E. Widdicombe
E. Malcolm S. Woodward
Amanda Beesley
Dave V. P. Conway
James Fishwick
Hannah Haines
Carolyn Harris
Roger Harris
Pierre Hélaouët
David Johns
Penelope K. Lindeque
Thomas Mesher
Abigail McQuatters-Gollop
Joana Nunes
Frances Perry
Ana M. Queiros
Andrew Rees
Saskia Rühl
David Sims
Ricardo Torres
Stephen Widdicombe
Abstract. The Western Channel Observatory (WCO) comprises a series of pelagic, benthic and atmospheric sampling sites within 40 km of Plymouth UK, which have been sampled by the Plymouth Institutes on a regular basis since 1903. This longevity of recording and the high frequency of observations provide a unique combination of data; for example temperature data were first collected in 1903 and the reference station L4 has been sampled on a weekly basis since 1988 where nearly 400 planktonic taxa have been enumerated. While the component datasets have been archived, here we provide the first summary database bringing together a wide suite of the observations. This provides monthly average values of some of the key pelagic and benthic measurements for the inshore site L4 (50° 15.00' N, 4° 13.02' W approx depth 55 m), the offshore site E1 (50° 02.00' N, 4° 22.00' W approx depth 75 m) and the intermediate L5 site (50° 10.80' N 4° 18.00' W approx depth 58 m. In brief, the data include: water temperature (from 1903); macronutrients (from 1934); dissolved inorganic carbon and total alkalinity (from 2008); methane and nitrous oxide (from 2011); chlorophyll a (from 1992); HPLC-derived pigments (from 1999); <20 μm plankton by flow cytometry including bacteria (8 functional groups from 2007); phytoplankton by microscopy (6 functional groups from 1992); microplankton and mesozooplankton from FlowCam (6 groups from 2012), Noctiluca sp. dinoflagellate (from 1997); mesozooplankton by microscopy (8 groups from 1988); Calanus helgolandicus egg production rates (from 1992); fish larvae from Young Fish Trawl survey (4 groups from 1924); benthic macrofauna (4 groups from 2008); demersal fish (19 families from 2008); blue shark, Prionace glauca (from 1958); 16S alpha diversity for sediment and water column (from 2012). These data have varying coverage in time and depth resolution. The metadata tables describe each data set, provide pointers to the source data and other related Western Channel Observatory data sets and outputs not compiled here. We provide summaries of the main trends in seasonality and some major, climate related shifts that have been revealed over the last century. The data are available from Data Archive for Seabed Species and Habitats (DASSH) via the link http://doi.org/10.17031/645110fb81749 (McEvoy and Atkinson, 2023). Making the data fully accessible and including units of both abundance and biomass will stimulate a variety of uptakes. These may include uses as an educational resource for projects, for models and budgets or for analysis of seasonality and long-term change in a coupled benthic-pelagic system and for supporting UK and Northeast Atlantic policy and management.
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Andrea J. McEvoy et al.
Status: final response (author comments only)
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RC1: 'Comment on essd-2023-311', Anonymous Referee #1, 11 Sep 2023
The manuscript by McEvoy and co-authors presents a first database bringing together a wide range of different observations from pelagic, benthic and atmospheric observations from the Western Channel Observatory close to Plymouth (UK). A general summary of sampling methods and metadata is provided together with main trends and discussions of biotic and abiotic parameters. While many of the presented time series are published and available in different resolutions from different resources, this is the first important attempt to summarize the different datasets in an integrated way by presenting monthly averages of the observed parameters. The provided database is intended facilitating the use of the long-term observations in the Western Channel Observatory for a variety of approaches, including supporting policy and management.
The manuscript is generally well written and of high importance for the community. I could not access the data via the enclosed link, but I assume this will be possible once the manuscript is accepted.
Some important aspects – the long-term funding of these kind of observatories and the future of long-term ecological research are discussed. Of particular importance is the fact that the use of future automatic systems can only be meaningful if used in a complementary manner with current (classic taxonomical) long-term observations.
I assume that the text passages of the different observations were provided by different co-authors and I would have some suggestions to make them a bit more coherent: Section 5.1 would benefit from some clarifications and lacks some discussion and interpretation of the results compared to the other sections. Some sections present detailed results, while other focus on general long-term trends – this could be presented more uniformly. Given the focus of the manuscript, the general trend/or in case of short time-series, a wider context is more meaningful here.
There is some general description for establishing the phytoplankton biomass in the main text included, while other methods, e.g. estimating zooplankton biomass, are only referred to in the appendix (by links that lead to other references). Because of the importance of biomass in the results presented, I would suggest to give a very short summary of the different methods of estimating biomass for the different groups in the main text body (e.g. wet weight on board, estimated by length weight relationships etc). There are a couple of formal corrections (see below).
Overall, I would recommend publications after minor revision.
Detailed comments:
Line 23: please close bracket
Line 54: please add a period at the end of the sentence
Line 59, 63: please add blanks before station names
Line 64: please delete blank before egg production
Line 129: please check structure of sentence
Line 130: The least squares linear regression indicates a constant increase in water T, however, a cooling period is indicated between 1962 and 1985. Please clarify, also, add a reference or, if it is referring to Southward et al., move reference
Line 185: consider rephrasing …. indicates that there are no data available
185: To benefit models, budgets and size-based approaches, biotic data
are reported both in units of abundance and biomass. – repetition from line 149, please consider deleting in one place
Line 180-192: Some methods for biomass estimations of phytoplankton are presented, but not for other organisms. See comment above, I would suggest to add brief descriptions for biomass estimations for the different groups.
Table 2: Please indicate reference for Nanoeukaryotes.
The first 2 paragraphs of section 5.1 are difficult to understand, please consider rephrasing
In detail:
Line 206: what are the alternative mechanisms that have been proposed and based on what, pleas add a brief summary here, otherwise the context is a bit odd.
Line 207: Please add period after bracket.
Line 215: Please rephrase ‘near limiting levels at the limit of detection’
Line 217: Please remove period after August
Line 219: causes
Line 220: There is no interpretation of the causal mechanisms
Line 222: Please delete ‘the’ before autumn
Line 222: please be more specific, what is meant by ‘the averages in Fig. 3’
Line 223: inter-annual variability in what? Phytoplankton concentration? Obviously, if you only show an average, you cannot depict any variability? Please consider rephrasing.
Line 225: what do you mean by ‘size boundary between phytoplankton and metazoans’? Please be more specific, the whole sentence is difficult to understand
Line 228: show important contributions to what, please rephrase or explain
Line 232: Paradoxically to what? Please be more specific. Maybe the food baseline is high enough to sustain an earl onset of secondary production?
Line 239: several blanks to much or a pdf error?
Line 243: biomass instead of biomasses? Low instead of depressed?
Line 250: Please consider moving the phytoplankton part to the corresponding paragraph in the beginning of the section
Figure caption Fig. 3: EP of Calanus was not measured from females from surface waters? Please correct. Also, please format blanks in several y-achsis labels and check units (see also Fig. 4)
Figure 3 f: TChl excludes chl a? Legend for this plot? From the appendix I get that TChl includes also Chl a, so Chl a would appear twice, distorting total pigment concentration?
Fig. 3i: how was nauplii carbon calculated?
Line 280: Biomass of plankton by flow cytometry derived from Table 2 – Do you mean using conversion factors in Table 2 (see also Fig. caption of Fig. 4)?
Section 5.2: I would suggest to remove detailed numbered referring to results (e.g. concentrations) to be consistent with 5.1
Title 5.2: This is more a comparison between E1/L5 and L4 than the overall seasonality of the former, please consider re-labelling
Line 303: time series data do instead of time series data does?
Line 310: Data….show instead of shows? Also, please delete 1m², 700µm, this information belongs into Table 1, where also mesh size of plankton nets is given
Line 312: Please explain shortly why you mention Calanus data here. Also, I would assume that they are not quantitatively retained in the 700µm net, a short remark would be helpful for understanding the context
Fig. 4 d: depth?
Line 347: originate from instead of are?
Line 447: please correct: macro-nutrients
Line 451: maybe the use of ‘sardine’ is more common than pilchard? Please consider correction throughout the text
Line 495: rate process measurement is an unusual expression. Maybe better only rate measurements?
Line 500: component weekly rates- do you mean Calanus weekly rates? Please rephrase
Line 507: Please correct to the commonly used ‘hatching success’
Section 5.5: I wonder why detailed measurements are presented here, when over the rest of the variables mainly trends are provided. Is there a reason for that? Then please comment in the beginning of the manuscript when describing the different variables/time series to facilitate the focus on this section. Otherwise detailed concentrations could be removed and the focus could be more on general trends and drivers
Fig. caption Fig. 8: please add station
Line 586: what is meant by triggering of biomass of diversity peaks? Please rephrase
Section 5.6 is not relating to any data presented her. Please consider either presenting the relevant data or shortening this section, as it is unrelated to the data submitted
Line 650: Consider rephrasing, the half sentence …. or the use of eDNA and bioinformatic processing of the enormous volumes of data collected… stands in a weird context. I would maybe suggest moving this topic two paragraphs down and add a couple of sentences regarding the challenges that come with the processing and storage of these ‘digital’/automatic/high resolution data.
Citation: https://doi.org/10.5194/essd-2023-311-RC1 -
RC2: 'Comment on essd-2023-311', Anonymous Referee #2, 16 Sep 2023
General comments
The manuscript proposed by A. J. McEvoy et al. aims giving a detailed description of a compiled monthly dataset from the Western Channel Observatory in the Western English Channel.
The presented dataset aggregates an important dataset ranging from hydrology to sharks and from microbial diversity up to benthic macrofauna and fish.
The manuscript is combining a detailed description of available data and some examples of observed trends and features observed in this region (referring to more focused published publications).
My main comment concerns the dataset access. Indeed, the proposed link http://doi.org/10.17031/645110fb81749 does not allow to access to a readable dataset (or I didn’t find the way to read data). It is then an issue to solve before publication.
Considering the limited needed improvements included in those comments and if the dataset confirms what is described in the publication, I recommend this paper for potential publication after minor revisions.
Specific comments
Title
In the title you talk about oceanographic data. Does it mean physical or hydrological data ?
p.2 / l. 38: The link does not work. We have an available landing page but when we try to get the data, we have a file named DASSHDT00000522 without extent (then the user doesn’t know how to open). I tried to open as a text or Excel file and it does not work.
Figure 2
The figure 2 illustrates the sea surface temperature large scale condition compared with E1 and L4 stations. Several point should be addressed for this figure:
- The source of SST in Figure 2a is not cited as well as the year plotted.
- A cooling period at L4 is mentioned but does not clearly appear in the trend. How is has been defined that the temperature is cooling during this period because it seems mainly driven by a cold year around 1985.
- Why only E1 is represented on this figure ? It would have been interesting to overplot signal at L4 et L5.
p.6 / l. 135 – please provide a link to the different datasets on those repositories.
p.6 / l. 135-138 – It has been mentioned that datasets have been monthly averaged to get similar sampling for the different variables. For parameters sensitive to the tidal activity (temperature, salinity, chlorphyll concentration, …), this choice can induce bias considering partial tidal cycle in the average. Did you investigate the impact of the monthly average on such variables compared to average considering full tidal cycle ?
Figure 4
For the young fish trawl, E1 and L5 data are combined. Could you explain how those two stations are combined ?
Figure 5
In the figure caption, it has been mentioned that “Trend lines are illustrative only, and do not necessarily imply statistical significance.”. However, those trends are discussed in the text. It would be interesting to explain how those trends are processed.
Minor and technical corrections
Abstract
p.1 / l. 26 – missing closing brackets after 58m.
p.2 / l.49 – missing point at the end of the sentence
p.2 / l.49 – please replace “re-use” by “reusable” to follow FAIR acronym.
p.8 / l.207 – missing point at the end of the sentence ( …. Atkinson et al., 2018). )
Figure 5 and Figure 6
Fonts in the figure are too small and the limited resolution of the figure does not allow to clearly read text. Please improve the resolution and the font size in the figure.
p.20 – notations for total alkalinity are not uniform (TA, AT)
p.20 / l. 555 – units for AT, DIC are missing as well as for density anomaly.
Figure 8
Please the same notation for total alkalinity in the figures (AT) and in the text (TA).
p.22 – Modelling could be replaced by “Numerical modelling”
Citation: https://doi.org/10.5194/essd-2023-311-RC2
Andrea J. McEvoy et al.
Data sets
The Western Channel Observatory: a century of oceanographic, chemical and biological data compiled from pelagic and benthic habitats in the Western English Channel 1903–2022 Andrea J. McEvoy, Angus Atkinson, Ruth L. Airs, Rachel Brittain, Ian Brown, Elaine S. Fileman, Helen S. Findlay, Louise McNeill, Clare Ostle, Tim J. Smyth, Paul J. Somerfield, Karen Tait, Glen A. Tarran, Simon Thomas, Claire E. Widdicombe, E. Malcolm S. Woodward, Amanda Beesley, Dave V. P. Conway, James Fishwick, Hannah Haines, Carolyn Harris, Roger Harris, Pierre Hélaouët, David Johns, Penelope K. Lindeque, Thomas Mesher, Joana Nunes, Frances Perry, Andrew Rees, Dave Sims, and Stephen Widdicombe https://doi.org/10.17031/645110fb81749
Andrea J. McEvoy et al.
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