2 open review comments to “Optical plankton imaging and analysis systems for ocean observation”
A decade ago during the OceanObs’99, one of the outcomes of the meeting gave birth to the Argo measurement network with profiling floats. One of the main requirements was the coherence of the database and availability of the data in near real time.
Optical plankton imaging is certainly a subject that will undergo significant development in near future because its potential use in monitoring programs. As noted in this white paper, the software systems are not mature yet therefore I am surprised that the use of commercial scanners for net zooplankton imaging is highlighted here. Their use on wide scale will introduce a variability of objects’ attributes that will make difficult to undertake global networking and comparative studies. Instead, I would propose to determine the criteria that should be fulfilled to allow the constitution of a coherent world wide databank for net zooplankton. This should include several levels: scans, 2D and 3D photographs. I think that it’s time to build a world wide monitoring of historical and new samples collections of net zooplankton in a coherent way and not through do-it-yourself systems. The ARGO network should serve as example.
An outcome of session 52 ‘Observing and Modeling the Size Structure of Plankton Communities’ at the ASLO 2009 Meeting was that detecting plankton and detritus size spectra was of great importance to quantify fluxes in marine systems.
In addition to the plankton and detritus quantification, size has also been put forward as an important property in models to simplify the complexity and diversity of marine systems. Several models take advantage of the size scaling properties of detritus (Stemmann et al., 2004; Gehlen et al., 2006) and organisms (Baird et al., 2004;Maury et al., 2007) but coherent large data sets over a wide range of environmental conditions are still needed to validate the different approaches. Recent works using different versions of the Underwater Video Profiler (UVP) have shown that a global comparison of zooplankton community in the mesopelagic layer and the estimate of vertical flux from the size of aggregates was possible using a single instrument but only if the imaging methods were carefully calibrated (Stemmann et al., 2008; Guidi et al., 2008).
As stated in the white paper, the information of zooplankton taxa given by imaging tools is necessary to understand and monitor the marine ecosystem. These tools are not only useful for planktonologist but also to the scientific community dealing with biogeochemical cycles of
elements and, in particular, the mesopelagic layer at global scale. Therefore the design of such imaging instruments to be mounted on autonomous platforms should arise from cross disciplinary discussions.
Therefore, I would highlight the following points:
1) The development of underwater imaging techniques to be used globally to monitor marine ecosystems should not only aim at studying plankton but also the detritus that comprises the global vertical flux. The size spectra of both components is of great importance.
2) Imaging systems are particularly useful for the study of the different processes of particle transformation by plankton in the mesopelagic layers. Discussions should be engaged between the different scientific communities.
3) Imaging systems are particularly useful for global observation systems. There is a need for an inter-calibration of different instruments to establish global comparisons or budgets.
Stemmann, L., K. Robert, M. Picheral, H. Paterson, A. Hosia, M. J. Youngbluth, F. Ibanez, L. Guidi, F. Lombard, G. Gorsky (2008) Global biogeography of fragile macrozooplankton in the upper 100-1000 m depth inferred from the Underwater Video Profiler. ICES J. Mar. Sci. 65: 433-442
Guidi, L., G. A. Jackson, L. Stemmann, J. C. Miquel, M. Picheral, G. Gorsky (2008). Particle size distribution and flux in the mesopelagic: a close relationship. Deep-Sea Res. I. 55: 1364-1374
Stemmann L., G., Jackson, G. Gorsky (2004). A vertical model of particle size distributions and fluxes in the midwater column that includes biological and physical processes. II. Application to a three year survey in the NW Mediterranean Sea .Deep Sea Research I 51 (7): 865-884
Baird ME, Oke PR, Suthers IM, Middleton JH (2004) A plankton population model with biomechanical descriptions of biological processes in an idealised 2D ocean basin. Journal of Marine Systems 50:199-222
Gehlen M, Bopp L, Ernprin N, Aumont O, Heinze C, Raguencau O (2006) Reconciling surface ocean productivity, export fluxes and sediment composition in a global biogeochemical ocean model. Biogeosciences 3:521-537
Maury, O. et al., 2007. Modeling environmental effects on the size-structured energy flow through marine ecosystems. Part 1: The model. Progress in Oceanography, 74(4): 479-499.
ASLO 2009 Aquatic Sciences Meeting, “A Cruise Through Nice Waters”,
25-30 January 2009, Nice, France Session 52: Observing and Modeling the Size Structure of Plankton Communities Co-chairs: François Carlotti, Lars Stemmann, Meng Zhou