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Kohn, Marion; Zonneveld, Karin A F (2009): Seawater samples along several inshore-offshore transects off NW Africa and SE Africa [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.729702, Supplement to: Kohn, M; Zonneveld, KAF (2010): Calcification depth and spatial distribution of Thoracosphaera heimii cysts: Implications for palaeoceanographic reconstructions. Deep Sea Research Part I: Oceanographic Research Papers, 57(12), 1543-1560, https://doi.org/10.1016/j.dsr.2010.09.004

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Abstract:
For the optimal use in palaeoceanographic studies of the stable oxygen isotopic signal and elemental composition of the calcareous photosynthetic dinoflagellate Thoracosphaera heimii, it is essential to gain detailed information about its calcification depth and spatial distribution. We therefore studied the vertical and horizontal distribution patterns of T. heimii in the upper water column (0-200 m) along three transects: an inshore-offshore gradient off Cape Blanc (CB), a south-north transect from CB to the Portuguese coast and a north-south transect off Tanzania. We compared concentrations of living cysts (cells with cell content) with chlorophyll-a, salinity and temperature measurements at the sampling depth. In order to explore the seasonal variability in cyst production, three transect off CB were sampled at three different times of the year.
Living T. heimii cysts were found in the upper 160 m of the water column with highest concentrations in the photic zone indicating that the calcification of T. heimii occurs in the upper part of the water column. Maximal abundances of living cysts were found relatively often in or just above the deep chlorophyll maximum (DCM), the depth of which varies regionally from about 20-40 m off CB to about 80 m off Tanzania and along the transect from CB to the Portuguese Coast. However, there was no significant correlation at the 95% confidence level between the cyst concentrations and temperature, salinity and chlorophyll-a concentrations at the sampling depths observed.
In both the Atlantic and Indian Oceans, the highest abundances of T. heimii were observed in regions where the upper water masses contained relatively low nutrient concentrations that are influenced only sporadically, or not at all, by enhanced photic zone mixing related to the presence of upwelling cells or river outflow plumes at or close to the sampling sites. The seasonal production of cysts by T. heimii appears to be negatively related to the presence of upwelling filaments across the sampling sites. Our study suggests that turbulence of the upper water masses is a major environmental factor influencing T. heimii production.
Coverage:
Median Latitude: 15.708176 * Median Longitude: -1.266926 * South-bound Latitude: -10.408500 * West-bound Longitude: -20.805830 * North-bound Latitude: 38.994667 * East-bound Longitude: 41.264000
Date/Time Start: 2006-10-23T13:15:00 * Date/Time End: 2008-05-28T16:18:00
Minimum DEPTH, water: 10 m * Maximum DEPTH, water: 200 m
Event(s):
GeoB11401-8 (876)  * Latitude: 21.275000 * Longitude: -20.773333 * Date/Time: 2006-10-23T13:15:00 * Elevation: -4152.0 m * Campaign: POS344/1 * Basis: Poseidon * Method/Device: Bottle, Niskin (NIS)
GeoB11402-2 (880)  * Latitude: 21.001667 * Longitude: -20.005000 * Date/Time: 2006-10-24T08:02:00 * Elevation: -3800.0 m * Campaign: POS344/1 * Basis: Poseidon * Method/Device: Bottle, Niskin (NIS)
GeoB11403-2 (883)  * Latitude: 20.835000 * Longitude: -19.248333 * Date/Time: 2006-10-25T08:13:00 * Elevation: -3375.0 m * Campaign: POS344/1 * Basis: Poseidon * Method/Device: Bottle, Niskin (NIS)
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethod/DeviceComment
Event labelEvent
DEPTH, waterDepth watermGeocode
VolumeVollKohn, Marionsampled
Thoracosphaera heimiiT. heimii#Kohn, Marion
Thoracosphaera heimiiT. heimii#Kohn, Marion
Temperature, waterTemp°CKohn, MarionCTD, Sea-Bird SBE 911plus
SalinitySalKohn, MarionCTD, Sea-Bird SBE 911plus
OxygenO2µmol/lKohn, MarionCTD, Sea-Bird SBE 911plus
Chlorophyll a, volume concentrationChl a vol concµl/lKohn, MarionCTD, Sea-Bird SBE 911plus
Size:
1335 data points

Data

Download dataset as tab-delimited text — use the following character encoding:


Event

Depth water [m]

Vol [l]
(sampled)

T. heimii [#]

T. heimii [#]

Temp [°C]

Sal

O2 [µmol/l]

Chl a vol conc [µl/l]
GeoB11401-8 1020144925.4436.71139.340.05
GeoB11401-820205625.1736.78140.680.09
GeoB11401-83020215325.1536.87143.360.08
GeoB11401-840200124.8236.88146.930.10
GeoB11401-850200723.3936.92144.700.34
GeoB11402-2 1020111725.1036.59209.900.06
GeoB11402-2202041025.1036.58210.800.07
GeoB11402-2302061424.5236.47211.240.15
GeoB11402-24020286523.5336.62214.370.25
GeoB11402-2452062622.3836.53206.330.45
GeoB11402-25020256121.6936.65185.790.32
GeoB11403-2 10202324.1036.70216.600.07
GeoB11403-22020802124.0136.71221.070.09
GeoB11403-230201002223.9336.73218.390.14
GeoB11403-24020833823.8736.73217.050.18
GeoB11403-2502022923.4636.72213.030.25
GeoB11403-26020671021.9736.57196.950.17
GeoB11404-4 10207224.5736.36209.460.08
GeoB11404-415206424.5536.34208.120.09
GeoB11404-420208224.5236.32205.880.13
GeoB11404-425207324.4136.28209.460.19
GeoB11404-430105523.6936.27204.540.39
GeoB11404-4402011421.4536.08183.110.21
GeoB11405-2 152015822.2136.07201.860.37
GeoB11405-22020221820.7536.18185.340.28
GeoB11405-22520291720.3336.21165.240.21
GeoB11405-230205420.2636.23167.920.17
GeoB11405-240196219.8336.18158.540.30
GeoB11405-250204019.1536.22166.140.33
GeoB11833-2 103012520.5336.07154.970.16
GeoB11833-2203025220.6336.54220.620.17
GeoB11833-23030186320.6536.59217.940.34
GeoB11833-24520883020.5336.66214.371.30
GeoB11833-27530761820.4836.91196.500.15
GeoB11833-210030981519.9136.86184.890.00
GeoB11834-1 103071020.0736.76156.761.33
GeoB11834-1203014020.0736.54221.961.41
GeoB11834-1303021220.0536.55225.091.47
GeoB11834-1403010019.9436.54227.772.00
GeoB11834-15030711119.9436.56222.851.27
GeoB11834-17030601218.4436.47163.900.00
GeoB11835-3 103017718.4136.07179.092.88
GeoB11835-3203020018.2936.10159.443.42
GeoB11835-330354018.2836.06214.372.15
GeoB11835-3402513018.2336.10213.921.21
GeoB11835-3503015417.2836.11179.980.00
GeoB11835-370305017.4736.25163.010.00
GeoB11836-1 10200018.07158.991.78
GeoB11836-1202012417.9936.04212.581.83
GeoB11836-130204518.2436.18206.331.28
GeoB11836-14020331117.7836.20193.380.72
GeoB11836-15020652417.4136.18172.390.12
GeoB11836-16020261016.9736.13161.670.01
GeoB11836-1701017016.8736.14148.270.00
GeoB11837-2 103012219.13147.381.31
GeoB11837-2203025319.1336.02209.461.38
GeoB11837-230307119.1336.02209.461.26
GeoB11837-240306218.9136.01203.200.87
GeoB11837-250307518.3736.12130.410.11
GeoB11837-26030181417.1336.0271.900.01
GeoB11837-2703030916.9136.0064.760.00
GeoB11839-1 10377019.1836.49221.071.52
GeoB11839-1203515019.1536.49231.342.10
GeoB11839-130305019.0336.49226.871.54
GeoB11839-140301019.0136.48223.751.36
GeoB11839-150307418.9836.47221.961.16
GeoB11839-170308518.3536.39183.550.00
GeoB13001-2 20404322.0836.42220.170.30
GeoB13001-250404921.1736.46222.410.64
GeoB13001-2654091120.7336.60222.411.20
GeoB13001-2754011119.9336.52197.400.91
GeoB13001-2160203514.8935.7768.330.22
GeoB13002-3 10300121.5236.31226.871.47
GeoB13002-320400121.5136.31228.661.51
GeoB13002-330400018.8736.07210.801.55
GeoB13002-340400118.7536.21176.850.58
GeoB13002-3100100216.6136.0880.830.26
GeoB13003-1 15500021.0636.28240.722.26
GeoB13003-130500020.4536.49230.450.95
GeoB13003-145400020.0936.61215.260.64
GeoB13003-165400018.6736.34184.000.33
GeoB13004-4 12400018.7935.92235.362.27
GeoB13004-420400018.1036.07196.501.65
GeoB13004-430400017.2336.06138.000.92
GeoB13004-440300016.6035.95124.150.56
GeoB13004-465200015.2035.7660.290.31
GeoB13004-4100100014.2235.5745.550.28
GeoB13005-2 15400019.0935.90215.711.75
GeoB13005-227400017.4535.89153.631.85
GeoB13005-250300016.4535.9074.141.71
GeoB13005-2100300114.5435.5951.360.39
GeoB13020-1 15305520.4336.57225.090.61
GeoB13020-130401120.4436.63224.190.83
GeoB13020-140401519.3736.50217.490.95
GeoB13020-1524016218.7436.48203.200.56
GeoB13020-1100200017.3536.34136.660.18
GeoB13024-4 203015219.6436.59232.230.36
GeoB13024-445305019.2436.60235.360.62
GeoB13024-4654037019.0436.64233.130.94
GeoB13024-4733051018.9236.63230.891.12
GeoB13024-4853013018.6636.63219.280.81
GeoB13024-41002024018.3936.60213.030.51
GeoB13030-2 3540191219.6836.57231.340.41
GeoB13030-25540231019.2036.56233.130.67
GeoB13030-2674020619.0536.65230.890.90
GeoB13030-2804023318.5836.58225.090.70
GeoB13030-2100201042418.3836.61218.390.43
GeoB13031-2 1030854320.7636.85223.750.21
GeoB13031-2504015520.0336.83229.550.33
GeoB13031-290408619.0336.79229.550.60
GeoB13031-21004096518.9836.79229.550.61
GeoB13032-1 1502023810
GeoB13032-1404037711119.6336.77228.210.28
GeoB13032-164304107418.8336.73231.790.41
GeoB13032-1844051018.4536.72229.550.68
GeoB13032-110040162018.3136.71226.430.52
GeoB13032-11501043017.7836.61221.510.30
GeoB13033-2 50400019.0936.73234.460.37
GeoB13033-2934047018.3636.70231.790.56
GeoB13033-21034037018.2836.69230.450.76
GeoB13033-21224044017.9936.65225.090.51
GeoB13033-2150104017.7036.59223.300.26
GeoB13034-1 504038418.4236.59235.800.37
GeoB13034-18040114018.1036.64232.680.46
GeoB13034-11004023017.8636.60231.340.78
GeoB13034-1117403017.6436.56226.430.69
GeoB13034-12002026014.9136.06207.220.27
GeoB13035-2 104011018.8236.29163.900.33
GeoB13035-2304026518.7036.49226.870.36
GeoB13035-250404017.6636.47240.720.39
GeoB13035-2704052017.1336.43237.590.65
GeoB13035-2100201816.7836.41234.460.57
GeoB13036-1 404029518.1236.51235.800.39
GeoB13036-175403116.9136.43241.610.66
GeoB13036-1854016016.8036.44238.481.05
GeoB13036-1110402016.3436.36231.790.61
GeoB13036-1140100015.7836.28226.430.35
GeoB13037-2 50402017.1136.16243.400.61
GeoB13037-260402016.5536.20246.080.81
GeoB13037-284400015.7636.22246.082.23
GeoB13037-2102400015.4636.21237.140.62
GeoB13037-2150200015.0336.16232.230.19
GeoB12602-1 4020900424
GeoB12602-16020343424.5135.08211.690.49
GeoB12602-18020334124.0435.13209.010.56
GeoB12602-110020221122.7235.28187.570.50
GeoB12602-115010193818.3535.29145.590.25
GeoB12604-1 1020142226.7134.49138.000.31
GeoB12604-1252081725.6935.11204.540.79
GeoB12604-1502061724.3235.10208.560.58
GeoB12604-1751082323.1935.24201.860.80
GeoB12604-11002014422.0335.26174.620.48
GeoB12604-1125204220.3235.30156.310.28
GeoB12608-3 102522826.6735.19108.080.19
GeoB12608-325256426.2535.11203.650.25
GeoB12608-350254725.7635.11204.990.82
GeoB12608-375224422.2635.27180.430.51
GeoB12608-3100224821.7835.26169.710.42
GeoB12608-31251521119.0135.33149.160.21
GeoB12608-315050917.5735.30142.020.18
GeoB12611-4 102011627.9534.46124.600.20
GeoB12611-450300527.2535.08200.520.24
GeoB12611-475302223.8135.10206.330.72
GeoB12611-4100303320.5035.34158.990.65
GeoB12611-4150203216.2635.21126.830.17
GeoB12616-2 20207328.2934.93195.610.20
GeoB12616-240304228.1334.95196.500.22
GeoB12616-275304124.7835.03204.100.70
GeoB12616-2100203422.3735.14161.220.65
GeoB12616-2125202418.7635.15104.950.34
GeoB12616-2150100117.3135.17101.820.28
GeoB12617-3 50203126.9534.92200.080.33
GeoB12617-3752011
GeoB12617-31002022
GeoB12618-2 20200127.6734.83197.400.26
GeoB12618-250300026.6434.94199.630.33
GeoB12618-260203226.5534.95200.080.31
GeoB12618-275301124.3735.10196.500.43
GeoB12618-2100300021.4035.28168.370.43
GeoB12618-2125200120.0835.35164.350.29
GeoB12618-2150100016.3135.35157.200.22
GeoB12620-4 20200027.6834.61167.480.25
GeoB12620-440200127.6934.77198.740.22
GeoB12620-460200025.2434.98206.780.44
GeoB12620-480300023.8235.06193.381.08
GeoB12620-4100200021.8835.18168.810.60
GeoB12620-4150100017.7635.27129.510.18
GeoB12621-2 50201125.8134.99202.760.50
GeoB12621-265302625.3035.04204.540.64
GeoB12621-21252000
GeoB12622-1 40200027.9434.79196.950.19
GeoB12622-170303423.5535.01180.430.93
GeoB12622-1100200321.4835.43181.320.60
GeoB12622-1150100217.3535.19117.900.24