de.pangaea.dataset996239 und de.pangaea.dataset996263 dataset PANGAEA
info@pangaea.de
https://www.pangaea.de/ information pointOfContact 2026-07-31T08:36:30Z https://doi.pangaea.de/10.1594/PANGAEA.996239 <gco:CharacterString>Coccolith abundance, assemblage structure, and sedimentological properties along core DA12‑11/2‑ST1‑GC01</gco:CharacterString> 2026-07-31T08:36:04 publication Ukpabi, Ndubuisi
edgar2005ng@gmail.com
https://orcid.org/0000-0002-8535-9041 information author Seidenkrantz, Marit-Solveig
mss@geo.au.dk
https://orcid.org/0000-0002-1973-5969 information author PANGAEA
info@pangaea.de
https://www.pangaea.de/ information publisher tableDigital This dataset presents a high resolution sequence of coccolithophore assemblages and absolute abundances from 0–419 cm in core DA12 11/2 ST1 GC01, capturing fine scale ecological variability across predominantly dark grey calcareous ooze interspersed with discrete ash layers. Coccolith counts range from extremely low values in ash dominated horizons to >900 specimens in more stable intervals, with absolute abundances varying by over two orders of magnitude. Assemblages are consistently dominated by Coccolithus pelagicus, Gephyrocapsa spp., and Emiliania huxleyi, whose shifting proportions delineate transitions between cool, stratified, and nutrient rich surface water states. Upper Holocene samples show strong C. pelagicus dominance with intermittent increases in E. huxleyi, reflecting oscillations between Atlantic influenced and Polar modified waters. Mid core intervals exhibit pronounced rises in Gephyrocapsa spp., marking episodes of enhanced small form productivity and possible changes in mixing intensity. Occasional occurrences of Helicosphaera carteri, Syracosphaera pulchra, Umbilicosphaera spp., and rare Pontosphaera taxa indicate intermittent incursions of warmer or more oligotrophic conditions. Ash layers consistently show reduced counts, simplified assemblages, and strong dominance by a single taxon, reflecting ecological suppression during volcanic deposition. Across the full sequence, the interplay between dominant and accessory taxa reveals coherent patterns of hydrographic restructuring, including shifts in thermal regimes, salinity gradients, nutrient supply, and stratification intensity. These assemblage variations provide a detailed ecological fingerprint of Holocene surface water dynamics in the Iceland Basin and form the basis for subsequent derivation of ecological contrasts and hydrographic indices. completed Ukpabi, Ndubuisi
edgar2005ng@gmail.com
https://orcid.org/0000-0002-8535-9041 information principalInvestigator absolute abundance assemblage dynamics Atlantic Water coccolith assemblages hydrographic interpretation Micropaleontology Paleoceanography quantitative microscopy sediment core DA12 11/2 ST1 GC01 SEM taxon ecology theme <gco:CharacterString>PANGAEA Keyword List</gco:CharacterString> 1995-01-01 creation PANGAEA
info@pangaea.de
https://www.pangaea.de/ information pointOfContact copyright copyright CC-BY-4.0: Creative Commons Attribution 4.0 International textTable und geoscientificInformation -20.70273 -20.70273 61.60893 61.60893 2025-09-12T14:20:00 2025-09-12T14:20:00 0.005 4.18 DEPTH, sediment/rock physicalMeasurement m m Depth, top/min physicalMeasurement m m Depth, bottom/max physicalMeasurement m m Color description thematicClassification Sediment colour Sediment type thematicClassification Description Coccoliths, total physicalMeasurement Counting, coccoliths # # Fields physicalMeasurement Number of fields of view # # Radius physicalMeasurement Petri dish radius cm cm Radius physicalMeasurement Optical field radius cm cm Subsample, dry mass physicalMeasurement Subsample weight g g Sample, dry mass physicalMeasurement Initial sample weight g g Coccoliths physicalMeasurement Counting, coccoliths; Absolute coccolith number 10**6 # 10**6 # Coccoliths physicalMeasurement Counting, coccoliths; Absolute coccolith abundance 10**6 #/g 10**6 #/g Calcidiscus leptoporus physicalMeasurement Counting, coccoliths # # Calcidiscus leptoporus physicalMeasurement Counting, coccoliths % % Coccolithus pelagicus physicalMeasurement Counting, coccoliths # # Coccolithus pelagicus physicalMeasurement Counting, coccoliths % % Helicosphaera carteri physicalMeasurement Counting, coccoliths # # Helicosphaera carteri physicalMeasurement Counting, coccoliths % % Gephyrocapsa spp. physicalMeasurement Counting, coccoliths # # Gephyrocapsa spp. physicalMeasurement Counting, coccoliths % % Emiliania huxleyi physicalMeasurement Counting, coccoliths # # Emiliania huxleyi physicalMeasurement Counting, coccoliths % % Syracosphaera pulchra physicalMeasurement Counting, coccoliths # # Syracosphaera pulchra physicalMeasurement Counting, coccoliths % % Umbilicosphaera spp. physicalMeasurement Counting, coccoliths # # Umbilicosphaera spp. physicalMeasurement Counting, coccoliths % % Pontosphaera discopora physicalMeasurement Counting, coccoliths # # Pontosphaera discopora physicalMeasurement Counting, coccoliths % % Pontosphaera japonica physicalMeasurement Counting, coccoliths # # Pontosphaera japonica physicalMeasurement Counting, coccoliths % % Braarudosphaera bigelowii physicalMeasurement Counting, coccoliths # # Braarudosphaera bigelowii physicalMeasurement Counting, coccoliths % % text/tab-separated-values unknown https://doi.pangaea.de/10.1594/PANGAEA.996239?format=textfile download dataset The data set was checked for completeness, correctness, and consistency of metainformation. Validity of used methods was checked and - if applicable - precision and range of data. EVENT LABEL: DA12-11/2-GC01 (G1) * LATITUDE: 61.608930 * LONGITUDE: -20.702730 * DATE/TIME: 2025-09-12T14:20:00 * ELEVATION: -2120.0 m * LOCATION: Iceland Basin * CAMPAIGN: Dana12-11 * BASIS: Dana (1981) * METHOD/DEVICE: Gravity corer 2025-09-12T14:20:00 Related to <gco:CharacterString>Holocene hydrography of the Iceland Basin from coccolith ecological contrasts: A multi‑axis index for salinity and stratification</gco:CharacterString> Ukpabi, Ndubuisi
edgar2005ng@gmail.com
https://orcid.org/0000-0002-8535-9041 information author Seidenkrantz, Marit-Solveig
mss@geo.au.dk
https://orcid.org/0000-0002-1973-5969 information author documentHardcopy Marine Micropaleontology