Status: this preprint is currently under review for the journal ESSD.
A global marine particle size distribution dataset obtained with the Underwater Vision Profiler 5
Rainer Kiko1,,Marc Picheral1,,David Antoine2,1,Marcel Babin3,Léo Berline4,Tristan Biard5,Emmanuel Boss6,Peter Brandt7,8,Francois Carlotti4,Svenja Christiansen9,Laurent Coppola1,Leandro de la Cruz10,Emilie Diamond-Riquier1,Xavier Durrieu de Madron11,Amanda Elineau12,Gabriel Gorsky1,Lionel Guidi1,Helena Hauss7,Jean-Olivier Irisson1,Lee Karp-Boss6,Johannes Karstensen7,Dong-gyun Kim13,Rachel M. Lekanoff14,Fabien Lombard1,Rubens M. Lopes10,Claudie Marec3,Andrew M. P. McDonnell14,Daniela Niemeyer7,Margaux Noyon15,Stephanie H. O'Daly14,Mark Ohman16,Jessica L. Pretty14,Andreas Rogge17,13,Sarah Searson18,Masashi Shibata19,Yuji Tanaka20,Toste Tanhua7,Jan Taucher7,Emilia Trudnowska21,Jessica S. Turner22,Anya Waite23,and Lars Stemmann1Rainer Kiko et al.Rainer Kiko1,,Marc Picheral1,,David Antoine2,1,Marcel Babin3,Léo Berline4,Tristan Biard5,Emmanuel Boss6,Peter Brandt7,8,Francois Carlotti4,Svenja Christiansen9,Laurent Coppola1,Leandro de la Cruz10,Emilie Diamond-Riquier1,Xavier Durrieu de Madron11,Amanda Elineau12,Gabriel Gorsky1,Lionel Guidi1,Helena Hauss7,Jean-Olivier Irisson1,Lee Karp-Boss6,Johannes Karstensen7,Dong-gyun Kim13,Rachel M. Lekanoff14,Fabien Lombard1,Rubens M. Lopes10,Claudie Marec3,Andrew M. P. McDonnell14,Daniela Niemeyer7,Margaux Noyon15,Stephanie H. O'Daly14,Mark Ohman16,Jessica L. Pretty14,Andreas Rogge17,13,Sarah Searson18,Masashi Shibata19,Yuji Tanaka20,Toste Tanhua7,Jan Taucher7,Emilia Trudnowska21,Jessica S. Turner22,Anya Waite23,and Lars Stemmann1
Received: 16 Feb 2022 – Discussion started: 12 Apr 2022
Abstract. Marine particles of different nature are found throughout the global Ocean. The term "marine particles" describes detritus aggregates, fecal pellets, but also bacterio-, phyto-, zooplankton and nekton. Here we present a global particle size distribution dataset obtained with several Underwater Vision Profiler 5 (UVP5) camera systems. Overall, within the 64 μm to about 50 mm size range covered by the UVP5, detrital particles are the most abundant component of all marine particles in this size range and thus measurements of the particle size distribution with the UVP5 can yield important information on detrital particle dynamics. During deployment, which is possible down to 6000 m depth, the UVP5 images a volume of about 1 L at a frequency of 6 to 20 Hz. Each image is segmented in real time and size measurements of particles are automatically stored. All UVP5 units used to generate the here presented dataset were inter-calibrated using a UVP5 High Definition unit as reference. Our consistent particle size distribution dataset contains 8805 vertical profiles collected between 2008-06-19 and 2020-11-23. All major ocean basins, as well as the Mediterranean and the Baltic Sea were sampled. 19 % of all profiles had a maximum sampling depth shallower than 200 dbar, 80 % had a maximum sampling depth greater than 200 dbar, 38 % sampled at least the upper 1000 dbar depth range and 11 % went down to at least 3000 dbar depth. First analysis of the particle size distribution dataset shows that particle abundance is found to be high at high latitudes and in coastal areas where surface productivity or continental inputs are elevated. Lowest values are found in the deeep ocean and in the oceanic gyres. Our dataset should be valuable for more in-depth studies that focus on the analysis of regional, temporal and global patterns of particle size distribution and flux as well as for the development and adjustment of regional and global biogeochemical models. The marine particle size distribution dataset (Kiko et al., 2021) is available at https://doi.pangaea.de/10.1594/PANGAEA.924375.
The manuscript by Rainier Kiko and his cohort introduces the data base that they have assembled for particle size profiles made around the world and that they placed online to make the database generally available. The data were obtained using UVP5 particle sizers after the instruments had been being calibrated in a consistent manner. The data have been stored in an easily accessible manner using a standard form. Their efforts have produced a valuable resource for the community.The UVP5 is probably the best calibrated optical particle counter used in oceanography. As with all techniques, there are quirks to the data and how they are interpreted that may not be realized by a user of this data set. I believe that it would help new users if the authors added a couple of paragraphs discussing some of the limitations of the data.
The observations are sorted into depth and size ranges, with the number of particles in each depth and diameter range divided by the associated water volume and diameter range to calculate a size spectrum. These are further processed by multiplying the number spectrum by the volume of a particle in the relevant size bin to yield a volume spectrum. The results in the data base are given as these two spectra, which are probably the most useful forms for most people studying particle distributions and dynamics.
Problems with calculated spectral data arise when there is only 1 particle observed in a depth and size range. The number of particles sampled in each depth and size interval can be calculated from the sample volumes and size ranges given in the in the data tables. Would the sampled water have only one particle of the observed size in any water sample of the same volume? Or, is the observed particle the one lucky enough to be sampled when the average particle concentration is actually one tenth or one hundredth of the above estimate? Because large particles are rarer than small ones, this uncertainty is more of an issue with them. It is particularly a problem for measures that multiply by particle volume, which is greater for the larger particles.
One solution for an individual using the data is to decrease the uncertainty by setting to 0 the spectral value calculated with only one particle. Alternatively, increasing the sample volume by increasing the depth range for each sample would decrease the depth resolution of the observations but should yield more particles in each depth bin, hopefully decreasing the number of size intervals with only 1 particle. Those sampling at sea have the option of simply increasing their sample volumes within a given depth range.
Understanding this issue is important for those who plan to use the data that the authors have accumulated.
Smaller issue: the manuscript needs to be consistent in its punctuation of references in the text, particularly in the use of parentheses. For example, line 27 uses only one set of parentheses, while line 30 uses two sets. Most of the text has author names inside parentheses for citations; lines 52-55 do not.
In summary, this is an important and useful paper for oceanography. It would benefit from adding couple of paragraphs describing issues associated with using discrete counts as if they are continuous concentrations. The manuscript also needs another pass to smooth out typographic inconsistencies.
The term "marine particles" comprises detrital aggregates, fecal pellets, but also bacterio-, phyto-, zooplankton and even fish. Here we present a global dataset that contains 8805 vertical particle size distribution profiles obtained with Underwater Vision Profiler 5 (UVP5) camera systems. This data is valuable to the scientific community as it can be used to constrain important biogeochemical processes in the Ocean, such as the flux of carbon to the deep sea.
The term "marine particles" comprises detrital aggregates, fecal pellets, but also bacterio-,...
