Aquatic palynomorphs from modern marine sediments in a reconnaissance transect across the Northwest Passage – Baffin Bay region

Surface sediments from 18 boxcores across the Canadian Arctic provide the first assessment of modern non-pollen, non-dinocyst palynomorph regional distribution patterns. Palynomorphs are abundant and well-preserved (~400–21,900 ind./g; average 5730 ind./g), comprising acritarchs, zoomorphs (invertebrate eggs, egg capsules, mouthparts), foraminiferal linings, tintinnid loricae, ciliate cysts, and freshwater algae. Acritarch P and Halodinium minor were the most abundant and widely distributed acritarchs (avg. ~410 and ~340 ind./g, respectively). Invertebrate eggs (avg. ~570 ind./g) and foraminiferal linings (avg. ~1600 ind./g) were prominent. Six tintinnid forms were identified, cf. Parafavella parumdentata (avg. ~40 ind./g; 10 stations) showing the widest distribution. Ciliate cysts included Strombidium? cyst A, a spherical, flask-shaped cell with short spines and a rounded base (avg. ~120 ind./g; 16 stations). Pediastrum sp. (avg. ~140 ind./g) and Botryococcus sp. (avg. ~1040 ind./g) were especially abundant in the west, likely delivered via rivers. Out of 14 environmental parameters only sedimentary biogenic silica (%Si(opal)) was significant in explaining palynomorph variation. At group level, tinitinnids showed the strongest positive correlation to %Si(opal). Individually, the tintinnid Acanthostomella? sp. 1, ciliate cyst Fusopsis? cyst A, and the acritarch Palaeostomocystis fritilla were almost solely and positively explained by %Si(opal). This suggests that %Si(opal) strongly determines palynomorph variability, particularly for microzooplankton, implying that siliceous organisms (diatoms) play an important role in shaping palynomorph content in the sedimentary record. Our data suggest that palynomorphs represent a valuable addition to organic-walled microfossils (dinocysts) routinely used in this region, offering a unique multiproxy glimpse into the ecosystem. •6 tintinnid and 6 ciliate cyst types were found in the Canadian Arctic Archipelago.•Aquatic palynomorphs are abundant and well preserved in surface marine sediments.•Acritarchs, foraminiferal linings, tintinnids, and freshwater algae are prominent.•Sedimentary %Si(opal) explained variability in palynomorph groups and individual taxa.•Our results encourage the use of aquatic palynomorphs as paleoenvironmental proxies.