Fig 1.
Sampling stations of the RoME Project.
The black dots indicate the sampling stations. The bathymetry data of the Ross Sea from [43] under a CC BY license, with permission from [Davey], original copyright [2004–2005].
Fig 2.
Sampling stations within each area, corresponding map of the upper mixed layer (UML) and the Θ/S diagram.
Station maps for the RoME 1, 2 and 3 (A, D, G, respectively). The bathymetry data of the Ross Sea from [43] under a CC BY license, with permission from [Davey], original copyright [2004–2005]. Map of the UML depth (colour scale) for the three areas (B, E, H). The Θ/S diagrams for each leg with indication of data shallower than the UML (red dots) and of the freezing point (C, F, I). UML maps and Θ/S diagrams produced through Ocean Data View software [44].
Fig 3.
Upper mixed layer (UML) depth (m) in the three areas (boxplot by RoME).
The red line shows the median, and the red cross the mean.
Table 1.
Mean (±standard deviations), minimum and maximum values, calculated in the upper mixed layer (UML) (A) and below the UML (B) for the three sampled areas.
Fig 4.
Environmental features in the two investigated layers of each area.
Temperature (°C), melt-water (%) and DIN [dissolved inorganic nitrogen] concentrations (μM). The red cross shows the mean. Samples in the UML (A) and samples below the UML (B).
Fig 5.
Biological features in the two investigated layers of each area.
Total biomass (mg Chl-a m-3), micro (>20 μm) fractions (%), diatoms (%), Haptophytes (%) and Fv/Fm [maximum quantum yield]. The red line is the median and red cross is the mean. Samples in the UML (A) and samples below the ULM (B).
Fig 6.
Results of PCA applied to physical, chemical and biological parameters.
Parameters included in the analysis: ΔSi/Fuco [ΔSi(OH)4/Fucoxanthin], Haptophytes (%), Si(OH)4 [silicate], DIN [dissolved inorganic nitrogen (NO3- + NO2- + NH4+)], PO43- [phosphate], Fv/Fm [maximum quantum yield], Total Chl-a, Diatoms (%), MW [melt-water] (%) and Temperature (°C). The samples in the UML (full shot-A) and samples below the ULM (cross-B): RoME 1, blu; RoME 2, green; and RoME 3, red.
Table 2.
Correlation matrix (Spearman) among physical, chemical and biological variables.
Table 3.
Spearman correlation matrixes between the phytoplankton and the POM features (quantitative: POC, protein and carbohydrate concentrations; qualitative: Protein to carbohydrate ratio, and POC/PON ratio) for the three sampled areas.