title: Life in a temperate Polar sea: a unique taphonomic window on the structure of a Late Cretaceous Arctic marine ecosystem.
abstract: As the earth faces a warming climate, the rock record reminds us that comparable climatic scenarios have occurred before. In the Late Cretaceous, Arctic marine organisms were not subject to frigid temperatures but still contended with seasonal extremes in photoperiod. Here, we describe an unusual fossil assemblage from Devon Island, Arctic Canada, that offers a snapshot of a ca 75 Myr ago marine palaeoecosystem adapted to such conditions. Thick siliceous biogenic sediments and glaucony sands reveal remarkably persistent high primary productivity along a high-latitude Late Cretaceous coastline. Abundant fossil faeces demonstrate that this planktonic bounty supported benthic invertebrates and large, possibly seasonal, vertebrates in short food chains. These ancient organisms filled trophic roles comparable to those of extant Arctic species, but there were fundamental differences in resource dynamics. Whereas most of the modern Arctic is oligotrophic and structured by resources from melting sea ice, we suggest that forested terrestrial landscapes helped support the ancient marine community through high levels of terrigenous organic input.
authors: Department of Geological Sciences, University of Colorado, Boulder, CO 80309, USA. karen.chin@colorado.edu
authors: Karen
authors: K
authors: Chin
authors: John
authors: J
authors: Bloch
authors: Arthur
authors: A
authors: Sweet
authors: Justin
authors: J
authors: Tweet
authors: Jaelyn
authors: J
authors: Eberle
authors: Stephen
authors: S
authors: Cumbaa
authors: Jakub
authors: J
authors: Witkowski
authors: David
authors: D
authors: Harwood
mesh_terms: D000818:Animals; D017377:Diatoms / Q000166:cytology; D004141:Dinoflagellida / Q000166:cytology; D017753:Ecosystem; D020387:Food Chain; D005580:Fossils; D019015:Geologic Sediments / Q000032:analysis*; D008386:Marine Biology / Q000379:methods*; D020957:Nunavut; D009792:Oceans and Seas; D010163:Paleontology / Q000379:methods*