EKAMSAT-2023 · Eastern Arabian Sea · June 11–17, 2023
Cruise region · 11.6°–12.5°N · 66.4°–67.9°E
FlowCAM TYPE libraries · 31 categories
Discrete stations · ST-2 through ST-26 · 4 depths
Peak Chl-a · 1.30 mg/m³ (western transect)
Fv/Fm mean · 0.43 · Active photosynthesis confirmed
W–E Chl-a gradient: 0.82 → 0.35 → 0.12 mg/m³ · coastal upwelling signal
EKAMSAT-2023 · Eastern Arabian Sea · June 11–17, 2023
Cruise region · 11.6°–12.5°N · 66.4°–67.9°E
FlowCAM TYPE libraries · 31 categories
Discrete stations · ST-2 through ST-26 · 4 depths
Peak Chl-a · 1.30 mg/m³ (western transect)
Fv/Fm mean · 0.43 · Active photosynthesis confirmed
W–E Chl-a gradient: 0.82 → 0.35 → 0.12 mg/m³ · coastal upwelling signal
Arabian Sea
June 2023
31 TYPE Categories
25 Stations
5,426 Measurements
EKAMSAT-2023
FlowCAM Phytoplankton Survey · Eastern Arabian Sea · Goes Lab, LDEO Columbia
A comprehensive high-resolution oceanographic survey of the Eastern Arabian Sea (EKAMSAT) using FlowCAM automated imaging flow cytometry. The cruise sampled 25 discrete stations across a latitude–longitude grid (~12°N, 66–68°E), with 4-depth profiles at each station, plus continuous underway sampling along the cruise track. 31 phytoplankton TYPE categories were identified using FlowCAM library classification.
NASA DSI Project · 200,000 ACCESS Credits Approved
Measurements
5,426
↑ underway+discrete
Cruise Days
5
Jun 11–17 2023
Stations
25
ST-2 → ST-26
TYPE Cats
31
FlowCAM library
Peak Chl-a
1.30 mg/m³
↑ western bloom
Mean Fv/Fm
0.43
active photosyn.
01
Cruise Track & Chlorophyll-a
Eastern Arabian Sea · 11.6°–12.5°N · 66.4°–67.9°E · 5,426 underway measurement points, colored by Chl-a concentration
Cruise Track · Eastern Arabian Sea · click any point for data
Low Chl (0.07)
High Chl (1.30 mg/m³)
Track pattern: Ship transected from ~67.9°E westward to ~66.4°E along 12°N,
then N–S transects. Strong W–E Chl-a gradient: western waters (<67°E) showed 0.7–1.30 mg/m³
— upwelling-driven bloom at the shelf break. Eastern oligotrophic waters averaged 0.12 mg/m³.
Key Measurements
Cruise areaEastern Arabian Sea
Latitude range11.60° – 12.54°N
Longitude range66.41° – 67.94°E
Survey datesJun 11–17, 2023
Survey duration5 days
Chl-a mean0.29 mg/m³
Chl-a peak1.30 mg/m³
Mean Fv/Fm0.427
Fv/Fm range0.20 – 0.64
Spatial Gradient
Mean Chl-a by longitude zone (mg/m³)
66.4–66.9°E (West)
0.82 mg/m³
66.9–67.4°E (Central)
0.35 mg/m³
67.4–67.9°E (East)
0.12 mg/m³
02
Chlorophyll-a & Fv/Fm Along Track
Continuous underway sampling — real data from EKAMSAT-MERGED-FILE-WORK-FILE.xlsx · 5,425 measurement cycles
Chlorophyll-a (Chl_B) · mg/m³
Bloom signature: Chl-a rises sharply west of 67°E, peaking at 1.30 mg/m³ — a clear upwelling-driven bloom in the western Arabian Sea.
Fv/Fm (Photosynthetic Efficiency)
Healthy photosynthesis: Mean Fv/Fm = 0.43 indicates cells are actively photosynthesizing. Values >0.4 suggest nutrient-replete conditions.
03
Discrete Stations Grid
25 stations (ST-2 → ST-26) × 4 depths (0M, 40M, 65M, 80M) = 100 samples · FlowCAM analysis at each station-depth
E–W Chlorophyll-a Gradient (underway transect at 12°N)
Arabian Sea coastal signal: Chl-a increases 7× from oligotrophic eastern waters (~0.1 mg/m³) to the western shelf-influenced bloom (~1.30 mg/m³). This spatial gradient is diagnostic of monsoon-driven coastal upwelling — cold, nutrient-rich water upwelling at the western boundary fuels the bloom while the eastern basin remains nutrient-limited.
Chl-a vs Fv/Fm — Bloom Physiology
Nutrient co-limitation: High-Chl stations show elevated Fv/Fm (0.45–0.60), confirming cells are nutrient-replete and photosynthetically active. Low-Chl eastern stations cluster at lower Fv/Fm (~0.30–0.38), indicating iron or nitrogen stress in oligotrophic waters — classic HNLC-adjacent pattern for the Arabian Sea.
Discrete Station Overview — 25 stations × 4 depths · click a station for depth profile
Stations ordered W→E by longitude. Chl-a zone and DCM (deep chlorophyll maximum) likelihood based on longitudinal bloom gradient.
04
FlowCAM TYPE Library
31 phytoplankton TYPE categories identified in EKAMSAT-2023 · Each TYPE has .flb + .edg + _lib_images_*.tif files
TYPE Categories
Library Structure
| File | Description | Size |
|---|---|---|
| .flb | FlowCAM library binary — particle features, classification data, TYPE assignments | 17–351 KB |
| .edg | Edge data — particle boundary coordinates for morphological analysis | 3–41 KB |
| _lib_images_*.tif | Multi-frame TIF containing cropped particle images for each TYPE | 111 KB–911 KB |
The master EKAMSAT-LIBRARY.flb (351 KB) contains all 31 TYPE categories. Individual TYPE files (TYPE-1.flb … TYPE-31.flb) provide per-category particle subsets.
Comparison: EKAMSAT vs BLOOFINZ
| Feature | EKAMSAT-2023 | BLOOFINZ-2022 |
|---|---|---|
| Classification | TYPE-1 → TYPE-31 | Named class folders |
| Library format | .flb + .edg + TIF | JPEG images/class |
| Region | Eastern Arabian Sea | E. Indian Ocean |
| Cruise year | 2023 | 2022 |
| Station format | ST-2 → ST-26 | BFZ-Cast-* |
| Depth variants | 0M, 40M, 65M, 80M | Multiple |
| Underway runs | ~500+ runs | ~2490 runs |
05
Underway Sampling
Continuous FlowCAM sampling throughout cruise track · Run folders named <run>-DDMMYYYY-<id>
EKAMSAT-FLOWCAM-2023-UNDERWAY
Continuous FlowCAM runs
Feb–Jun 2023
500+ run folders
Run Folder Structure
110-25002023-638338229699222945/
├── _run_summary.txt (864 B)
├── _notes.txt (57 B)
├── .lst (55.9 MB)
├── .edg (4.3 MB)
├── .ctx (4 KB)
├── _000076.tif (93 KB)
├── _000076_bin.tif (24 KB)
├── _000075.tif (1.5 MB)
├── _000075_bin.tif (49 KB)
└── … more numbered TIF pairs
File Type Reference
| Extension | Contents |
|---|---|
| .lst | Main particle list — all measurements, features, timestamps. Usually 10–60 MB per run. |
| .edg | Edge/boundary data for each detected particle. |
| .ctx | Context metadata — instrument settings, flow rate, volume sampled. |
| _N.tif | Multi-frame TIF: sequential particle images (every 512–4000 particles per file). |
| _N_bin.tif | Binary mask TIF: segmentation masks for the paired image TIF — used for Trichodesmium chain detection. |
| _run_summary.txt | FlowCAM run metadata: volume analyzed, particle count, concentration estimates. |
Underway Metrics
Parent folderEKAMSAT-FLOWCAM-2023-UNDERWAY
EKAMSAT-UNDERWAYDedicated subfolder
Naming pattern<run>-DDMMYYYY-<id>
Calibration imagecal_image_000001.tif
TIF pairingRGB + _bin mask
TrichodesmiumDetect via _bin.tif mask
Trichodesmium detection: Binary mask TIFs (_bin.tif) enable morphology-based
detection of Trichodesmium filamentous chains — same pipeline as BLOOFINZ but applied to
EKAMSAT underway data.
06
Complete Data Structure
Google Drive · EKAMSAT-2023-FLOWCAM · Full directory tree
Directory Tree
EKAMSAT-2023-FLOWCAM/
├── Station Coordinates/
│ ├── EKAMSAT-MERGED-FILE-WORK-FILE.xlsx (5.1 MB)
│ └── EKAMSAT-UNDERWAY-CHL.gif (163 KB)
├── EKAMSAT-FLOWCAM-2023-UNDERWAY/
│ ├── EKAMSAT-UNDERWAY/
│ ├── 110-25002023-638338229699222945/
│ ├── 110-25002023-638338223272326862/
│ └── … (500+ run folders)
├── EKAMSAT-2023-Libraries/
│ ├── EKAMSAT-LIBRARY.flb (351 KB)
│ ├── EKAMSAT-LIBRARY.edg (41 KB)
│ ├── EKAMSAT-LIBRARY_lib_images_000001.tif (911 KB)
│ ├── EKAMSAT-2023-TYPE-31.flb … TYPE-1.flb
│ └── … (TYPE-31 through TYPE-1 × 3 files each)
├── EKAMSAT-2023-FLOWCAM-DISCRETE/
│ ├── ST-26/ ST-25/ … ST-2/
│ └── each station: 0M/ 40M/ 65M/ 80M/ collages/
└── Goes-EKAMSAT-Presentation-ASLO-2024.pptx (410 MB)
Merged Oceanographic Data
EKAMSAT-MERGED-FILE-WORK-FILE.xlsx contains 5,426 rows of continuous underway measurements:
Date, Time_BTimestamp (MM/DD/YY)
Latitude, LongitudeShip GPS position
Chl_B, Chl_GChlorophyll (Blue/Green) mg/m³
Fv_Fm_B, Fv_Fm_GPhotosynthetic efficiency
Fpe1_R, Fpe2_R, Fpe3_RFluorescence phycoerythrin
PARPhotosynthetically active radiation
ACCESS-CI Compute
Project IDEES260204
Credits awarded200,000 ACCESS
ResourcesAnvil (A100) + ACES (H100)
Status✓ Approved Oct 2026
EKAMSAT-2023 · EASTERN ARABIAN SEA · GOES LAB LDEO
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