Fig 1.
Study area in the Southern Gulf of Mexico (SGoM).
Location of the study regions (Perdido and Coatzacoalcos) in oceanic waters over the continental slope (>500 m isobaths) and the deep region (>1,000 m) of the Southern Gulf of Mexico (SGoM). The nominal stations for the phytoplankton sampling conducted during "Malla Fina" (MF) cruises are shown for both sites.
Table 1.
Genera of dinoflagellates and diatoms identified and measured in lineal dimensions.
Fig 2.
Distribution of the greatest linear dimension (GLD, μm) of two phytoplankton groups.
Frequency histograms of cell size indicated by the GLD (μm) measured in genera of (A) dinoflagellates and (B) diatoms. Nano-, micro-, and meso-size categories are displayed at the X-axis. Note the larger bin numbers used for the meso-size class in diatoms.
Fig 3.
Microscope images of dinoflagellate genera collected in oceanic waters of the SGoM.
(A) Dinophysis, (B) Pyrophacus, (C) Ornithocercus, (D) Phalacroma, (E) Gyrodinium, and (F) Pyrocystis. Scale bars are indicated for each picture.
Fig 4.
Microscope images of diatom genera collected in oceanic waters of the SGoM.
(A) Coscinodiscus, (B) Cylindrotheca, (C) Asterolampra, (D) Chaetoceros, (E) Gossleriella tropica, and (F) Nitzschia. Scale bars are indicated for each picture.
Fig 5.
Distribution of carbon content per cell (pg C cell-1) of two phytoplankton groups.
Frequency histograms of carbon content per cell (pg C cell-1) estimated from cell biovolume calculations for genera of (A) dinoflagellates (blue bars) and (B) diatoms (red bars). Five carbon classes are indicated at the X-axis of both groups.
Fig 6.
Logarithmic (Log10) mean (±SD) of carbon content (pg C cell-1) for phytoplankton genera.
Average log-values of carbon per cell (pg C cell-1; lower panels) for genera of dinoflagellates (blue points) and diatoms (red points). Only taxa with more than 30 cell measurements per genus were included. Grey bars in the upper panels indicate the number of organisms analyzed for each genus. Blue and red dashed lines represent average carbon per cell of total dinoflagellates and diatoms, respectively. Dinoflagellate orders: AM, Amphidiniales; DI, Dinophysales; GO, Gonyaulacales; GY, Gymnodiniales; NO, Noctilucales; PE, Peridiniales; PR, Prorocentrales; TH, Thoracosphaerales; TO, Tovelliales.
Fig 7.
Logarithmic (Log10) minimum and maximum values of carbon content (pg C cell-1) for ocassional genera.
Minimum (light-colored bars) and maximum (dark-colored bars) log-values of carbon content (pg C cell-1; lower panels) for genera of dinoflagellates (blue bars) and diatoms (red bars) occasionally found in phytoplankton samples (i.e., <30 cells per genus). Grey bars in the upper panels indicate the number of organisms analyzed per genus. Asterisks denote genera with only a single cell measurement for the carbon content estimation (grey bars in the lower panels). Dinoflagellate orders: DI, Dinophysales; GO, Gonyaulacales; GY, Gymnodiniales; NO, Noctilucales; PE, Peridiniales; PY, Pyrocystales; TH, Thoracosphaerales.
Fig 8.
Relative per-cruise percentage of depth-integrated carbon biomass for dinoflagellate orders and diatom shapes.
Carbon biomass contribution (%) of dinoflagellate orders and diatom shapes in the euphotic zone (Zeu: surface to ~150 m depth) during MF1 (late winter 2016), MF2 (late summer 2016), and MF3 (spring 2018) cruises. Dinoflagellate orders: DI, Dinophysales; GY, Gymnodiniales; TO, Tovelliales; AM, Amphidiniales; NO, Noctilucales; PY: Pyrocystales; GO, Gonyaulacales; PE, Peridiniales; TH, Thoracosphaerales; PR, Prorocentrales. Diatom shapes: CENTRIC and PENNATE.
Table 2.
Per-cruise abundance (cells L-1) and carbon biomass (μg C L-1) of dinoflagellates and diatoms.
Fig 9.
Temperature (°C) and salinity per cruise in the upper euphotic zone.
Median values of temperature (°C; upper panel) and salinity (lower panel) from data recorded between 11–17 m depth (~50% surface irradiance, %Io) at the Perdido (PER) and Coatzacoalcos (COAT) regions during MF1 (late winter 2016), MF2 (late summer 2016), and MF3 (spring 2018) cruises. For each hydrographic variable, the rectangular box represents the middle 50% of the data, delimited by the lower quartile (Q1) and upper quartile (Q3). The median is represented by a straight line inside the box. Whiskers are drawn for the minimum and maximum values.
Fig 10.
Depth-integrated per-cruise carbon biomass (mg C m-2) of total dinoflagellates and diatoms.
Median values of integrated carbon biomass (mg C m-2) of total dinoflagellates (blue box-plots) and diatoms (red box-plots) in the euphotic zone (surface to ~150 m depth) at the Perdido (PER) and Coatzacoalcos (COAT) regions during MF1 (late winter 2016), MF2 (late summer 2016), and MF3 (spring 2018) cruises. The rectangular box represents the middle 50% of the data for each group, delimited by the lower quartile (Q1) and upper quartile (Q3). The median is represented by a straight line inside the box. Whiskers are drawn for the minimum and maximum values. Y-axis is logarithmically scaled.
Fig 11.
Depth-integrated per-cruise carbon biomass (mg C m-2) of dinoflagellate orders and diatom shapes.
Median values of integrated carbon biomass (mg C m-2) in the euphotic zone of (A) dinoflagellate orders contributing 75% or more to total biomass (box plots at the upper panel) and (B) centric and pennate diatoms (green and yellow box-plots at the lower panel, respectively) at the Perdido (PER) and Coatzacoalcos (COAT) regions during MF1 (late winter 2016), MF2 (late summer 2016), and MF3 (spring 2018) cruises. The rectangular box represents the middle 50% of the data for each group, delimited by the lower quartile (Q1) and upper quartile (Q3). The median is represented by a straight line inside the box. Whiskers are drawn for the minimum and maximum values. Different logarithmic scales in the Y-axis are used for dinoflagellates and diatoms. Dinoflagellate orders: GY, Gymnodiniales (orange box-plots); GO, Gonyaulacales (dark blue box-plots); PE, Peridiniales (brown box-plots); DI, Dinophysales (light blue box-plots).