Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Aarhus University AU http://www.au.dk/en/ https://ror.org/01aj84f44 Seidenkrantz Marit-Solveig mss@geo.au.dk 0000-0002-1973-5969 Aarhus University AU http://www.au.dk/en/ https://ror.org/01aj84f44 2026 Coccolith abundance, assemblage structure, and sedimentological properties along core DA12‑11/2‑ST1‑GC01 dataset https://doi.pangaea.de/10.1594/PANGAEA.996239 2026-07-31T08:36:04 https://doi.org/10.1594/PANGAEA.996263 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. Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Seidenkrantz Marit-Solveig mss@geo.au.dk 0000-0002-1973-5969 in press Holocene hydrography of the Iceland Basin from coccolith ecological contrasts: A multi‑axis index for salinity and stratification journal article Marine Micropaleontology -20.70273 -20.70273 61.60893 61.60893 -20.70273 61.60893 2025-09-12T14:20:00 2025-09-12T14:20:00 0.005 4.18 DA12-11/2-GC01 G1 61.60893 -20.70273 Iceland Basin -2120.0 2025-09-12T14:20:00 Dana12-11 Dana12-11 Reykjavik, Iceland 2012-09-24T00:00:00 2012-09-24 Hirtshals, Denmark 2012-09-30T00:00:00 2012-09-30 Dana (1981) https://dana.dtu.dk/en/historien-om-dana Røy, Hans Røy, Hans https://geo.au.dk/fileadmin/ingen_mappe_valgt/Paleoceanography_group/Benthic_Marine_Research_Course_Final_Report_2013_v3.pdf Dana (1981) https://dana.dtu.dk/en/historien-om-dana Gravity corer GC 2238 CC-BY-4.0 Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ DEPTH, sediment/rock Depth sed m depth http://purl.obolibrary.org/obo/PATO_0001595 sediment http://purl.obolibrary.org/obo/ENVO_00002007 rock Length L http://dbpedia.org/resource/Length Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Depth sed [m] Depth, top/min Depth top m depth http://purl.obolibrary.org/obo/PATO_0001595 Length L http://dbpedia.org/resource/Length Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Depth top [m] Depth, bottom/max Depth bot m depth http://purl.obolibrary.org/obo/PATO_0001595 maximal max Length L http://dbpedia.org/resource/Length Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Depth bot [m] Color description Color descr Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Sediment colour Color descr (Sediment colour) Sediment type Sediment sediment http://purl.obolibrary.org/obo/ENVO_00002007 Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Description Sediment (Description) Coccoliths, total Cocco # total https://www.oxforddictionaries.com/definition/american_english/total Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Cocco [#] Fields Fields # Abundance or Count Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Number of fields of view Fields [#] (Number of fields of view) Radius Radius cm Radius https://www.marinespecies.org/aphia.php?p=taxdetails&id=431072 Length L http://dbpedia.org/resource/Length Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Petri dish radius Radius [cm] (Petri dish radius) Radius Radius cm Radius https://www.marinespecies.org/aphia.php?p=taxdetails&id=431072 Length L http://dbpedia.org/resource/Length Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Optical field radius Radius [cm] (Optical field radius) Subsample, dry mass Subsamp dm g dry mass https://en.wikipedia.org/wiki/Dry_matter Mass M http://dbpedia.org/resource/Mass Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Subsample weight Subsamp dm [g] (Subsample weight) Sample, dry mass Samp dm g dry mass https://en.wikipedia.org/wiki/Dry_matter Mass M http://dbpedia.org/resource/Mass Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Initial sample weight Samp dm [g] (Initial sample weight) Coccoliths Cocco 10**6 # Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Absolute coccolith number Cocco [10**6 #] (Absolute coccolith number) Coccoliths Cocco 10**6 #/g Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Absolute coccolith abundance Cocco [10**6 #/g] (Absolute coccolith abundance) Calcidiscus leptoporus C. leptoporus # http://www.marinespecies.org/aphia.php?p=taxdetails&id=235923 Calcidiscus leptoporus https://www.marinespecies.org/aphia.php?p=taxdetails&id=235923 Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 C. leptoporus [#] Calcidiscus leptoporus C. leptoporus % http://www.marinespecies.org/aphia.php?p=taxdetails&id=235923 Calcidiscus leptoporus https://www.marinespecies.org/aphia.php?p=taxdetails&id=235923 Dimensionless Ratio ψ Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 C. leptoporus [%] Coccolithus pelagicus C. pelagicus # Coccolithus pelagicus https://www.marinespecies.org/aphia.php?p=taxdetails&id=178600 Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 C. pelagicus [#] Coccolithus pelagicus C. pelagicus % Coccolithus pelagicus https://www.marinespecies.org/aphia.php?p=taxdetails&id=178600 Dimensionless Ratio ψ Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 C. pelagicus [%] Helicosphaera carteri H. carteri # http://www.marinespecies.org/aphia.php?p=taxdetails&id=615435 Helicosphaera carteri https://www.marinespecies.org/aphia.php?p=taxdetails&id=615435 Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 H. carteri [#] Helicosphaera carteri H. carteri % http://www.marinespecies.org/aphia.php?p=taxdetails&id=615435 Helicosphaera carteri https://www.marinespecies.org/aphia.php?p=taxdetails&id=615435 Dimensionless Ratio ψ Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 H. carteri [%] Gephyrocapsa spp. Gephyrocapsa spp. # http://www.marinespecies.org/aphia.php?p=taxdetails&id=235823 Gephyrocapsa https://www.marinespecies.org/aphia.php?p=taxdetails&id=235823 Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Gephyrocapsa spp. [#] Gephyrocapsa spp. Gephyrocapsa spp. % http://www.marinespecies.org/aphia.php?p=taxdetails&id=235823 Gephyrocapsa https://www.marinespecies.org/aphia.php?p=taxdetails&id=235823 Dimensionless Ratio ψ Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Gephyrocapsa spp. [%] Emiliania huxleyi E. huxleyi # http://www.marinespecies.org/aphia.php?p=taxdetails&id=115104 Emiliania huxleyi https://www.marinespecies.org/aphia.php?p=taxdetails&id=115104 Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 E. huxleyi [#] Emiliania huxleyi E. huxleyi % http://www.marinespecies.org/aphia.php?p=taxdetails&id=115104 Emiliania huxleyi https://www.marinespecies.org/aphia.php?p=taxdetails&id=115104 Dimensionless Ratio ψ Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 E. huxleyi [%] Syracosphaera pulchra S. pulchra # http://www.marinespecies.org/aphia.php?p=taxdetails&id=235979 Syracosphaera pulchra https://www.marinespecies.org/aphia.php?p=taxdetails&id=235979 Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 S. pulchra [#] Syracosphaera pulchra S. pulchra % http://www.marinespecies.org/aphia.php?p=taxdetails&id=235979 Syracosphaera pulchra https://www.marinespecies.org/aphia.php?p=taxdetails&id=235979 Dimensionless Ratio ψ Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 S. pulchra [%] Umbilicosphaera spp. Umbilicosphaera spp. # http://www.marinespecies.org/aphia.php?p=taxdetails&id=235857 Umbilicosphaera https://www.marinespecies.org/aphia.php?p=taxdetails&id=235857 Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Umbilicosphaera spp. [#] Umbilicosphaera spp. Umbilicosphaera spp. % http://www.marinespecies.org/aphia.php?p=taxdetails&id=235857 Umbilicosphaera https://www.marinespecies.org/aphia.php?p=taxdetails&id=235857 Dimensionless Ratio ψ Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 Umbilicosphaera spp. [%] Pontosphaera discopora P. discopora # Pontosphaera discopora https://www.marinespecies.org/aphia.php?p=taxdetails&id=235970 Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 P. discopora [#] Pontosphaera discopora P. discopora % Pontosphaera discopora https://www.marinespecies.org/aphia.php?p=taxdetails&id=235970 Dimensionless Ratio ψ Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 P. discopora [%] Pontosphaera japonica P. japonica # Pontosphaera japonica https://www.marinespecies.org/aphia.php?p=taxdetails&id=555941 Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 P. japonica [#] Pontosphaera japonica P. japonica % Pontosphaera japonica https://www.marinespecies.org/aphia.php?p=taxdetails&id=555941 Dimensionless Ratio ψ Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 P. japonica [%] Braarudosphaera bigelowii B. bigelowii # http://www.marinespecies.org/aphia.php?p=taxdetails&id=235922 Braarudosphaera bigelowii https://www.marinespecies.org/aphia.php?p=taxdetails&id=235922 Abundance or Count Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 B. bigelowii [#] Braarudosphaera bigelowii B. bigelowii % http://www.marinespecies.org/aphia.php?p=taxdetails&id=235922 Braarudosphaera bigelowii https://www.marinespecies.org/aphia.php?p=taxdetails&id=235922 Dimensionless Ratio ψ Counting, coccoliths Ukpabi Ndubuisi edgar2005ng@gmail.com 0000-0002-8535-9041 B. bigelowii [%] CurationLevelC Enhanced curation https://wiki.pangaea.de/wiki/Curation_levels absolute abundance assemblage dynamics Atlantic Water coccolith assemblages hydrographic interpretation Micropaleontology Paleoceanography quantitative microscopy sediment core DA12 11/2 ST1 GC01 SEM taxon ecology author118597 author28069 basis4446 campaign3423278 curlevel30 event2970337 geocode1 geocode1599 geocode1600 geocode1601 geocode8128 inst20913 journal10825 license21 method11107 method4786 param1052 param105760 param112130 param113739 param1140 param1265 param1404 param14619 param14926 param156427 param20889 param20891 param20894 param20896 param20907 param21383 param3 param4 param433 param50868 param514590 param551909 param567700 param6141 param6157 param628 param7637 param84878 param88037 param89367 param906 pi118597 ref140894 term1061613 term1061640 term1061677 term1061682 term1061692 term1061718 term1061755 term1062263 term1062276 term1062352 term1069174 term1073131 term21355 term38253 term38263 term38561 term38564 term41056 term43794 term43863 term43892 term44025 term47129 term50476 term54576 term60911 term77707 term78404 term78406 term78407 term78411 term78412 term78430 term78431 term78432