Central Arctic Ocean paleoceanographic interpretations based on Late Cenozoic calcareous dinoflagellates

Gilbert, Mark W.; Clark, David L.

doi:10.1016/0377-8398(83)90017-8

Cited by 38 publications

(26 citation statements)

References 18 publications

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“…Clark et al [1980] and Clark [1982a, b] proposed that the Arctic Ocean has been icecovered for the last 5 m.y., with sea ice extent and thickness never less than is observed today. This conclusion was later modified by Gilbert andClark [1982/1983], who proposed that the Arctic was characterized by very thin or even periodically absent sea ice between 1.8 and 0.7 Ma but with perennial ice cover prior to 1.8 Ma and after 0.7 Ma. These suggestions contrast with those of Herman and Hopkins [ 1980], who proposed that perennial Arctic ice cover first formed about 0.7 Ma.…”

Section: Introductionmentioning

confidence: 99%

Climatic effects of reduced Arctic sea ice limits in the Giss II General Circulation Model

Raymo¹,

Rind²,

Ruddiman³

1990

Paleoceanography

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In this paper we present results of an atmospheric general circulation model (GCM) experiment in which Arctic sea ice limits were substantially reduced in all months. March sea ice limits were set equivalent to modem September limits, and all sea ice was removed in September. Sea ice coverage for other months varied between these two extremes. This climate sensitivity experiment makes predictions about mean northern hemisphere atmospheric conditions (including temperature, pressure, wind patterns, and precipitation) consistent with these boundary constraints. The major effects of reduced sea ice limits are observed in winter. They include large regional warming of the circum-Arctic region, northward migration of the Icelandic low pressure system, and strengthening of the Azores high. Changes in net heating over the North Atlantic Ocean suggest that increases in sea surface temperatures and salinities in this region would also accompany reductions in Arctic sea ice limits. In the wind field, a weakening of the polar easteries and an intensification of cyclonic circulation over the Norwegian-Greenland Sea suggest that surface water exchange between the Atlantic and Arctic would increase when sea ice limits are reduced. However, zonally averaged changes in strength of the westerlies or upper level jet stream are minimal. The late Pliocene cooling of the North Atlantic Ocean and North American Arctic margin may have been linked in part to the development of perennial sea ice cover.

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Section: Introductionmentioning

confidence: 99%

Climatic effects of reduced Arctic sea ice limits in the Giss II General Circulation Model

Raymo¹,

Rind²,

Ruddiman³

1990

Paleoceanography

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“…Superimposed upon the general cooling trend, a slight warming occurred during the early Miocene (Miller et al 1987;Crowley and North 1991;Berger and (Gilbert andClarke 1983) Kohring 1993. Cyst no.…”

Section: Miocenementioning

confidence: 98%

Distribution of calcareous dinoflagellates from the Maastrichtian to early Miocene of DSDP Site 357 (Rio Grande Rise, western South Atlantic Ocean)

Hildebrand-Habel¹,

Willems²

2000

International Journal of Earth Sciences

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The evolution of calcareous dinoflagellate communities has been investigated for the latest Cretaceous to earliest Neogene interval of the mid-latitude South Atlantic. In doing so, the response of calcareous dinoflagellates to Cenozoic climatic change has been addressed for the first time. Trends in species composition and distribution patterns of wall types indicate significant changes which correlate with major palaeoenvironmental modifications. A first major shift concerning the relative abundance of species and wall types occurred across the Cretaceous-Tertiary boundary. The associations remained stable during the entire Paleocene and Eocene. Only in the late Eocene did a dramatic decrease in temperature cause a slight diversification. A second major shift in the abundance patterns occurred across the Eocene-Oligocene boundary. The early Miocene warming is possibly reflected in the distinct increase in relative abundance of one species. The assemblages of calcareous dinoflagellates evidently react to major climatic changes during the Cenozoic. These poorly investigated organisms may thus provide an important contribution to the understanding of earth's palaeoclimatic evolution.

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“…When a dinoflagellate exits the cyst, it is surrounded by a gelatinous sheath which is shed at a later stage (Sarjeant, 1974). The cyst composition is organic and non-cellulose in nature, which resists decay from bacteria and fungi (and also resists breakage into the thecal plates of the motile form (Gilbert and Clark, 1983). The thecal plates are composed of cellulose and serve as structure for the motile cell (Lau et al, 2007).…”

Section: Background On the Life Cycle Of Dinoflagellatesmentioning

confidence: 99%

“…It is generally accepted that cysts have resulted from the resting stage of a dinoflagellate, and bear resemblance to the motile form (Evitt, 1963), remaining in the sediment after the dinoflagellate has exited the cyst, and left behind as part of the fossil record. The fossil cyst can be identified if they retain tabulation patterns similar to the thecal plates of the motile organism (Gilbert and Clark, 1983), by the number or placement of the processes, or the shape of the excystment opening (the archeopyle) (Fensome etal, 1996a;Evitt, 1967). Therefore dinoflagellates leave behind a selective record, since only cyst-forming species (approximately 10% of modern species) are represented biasing interpretations of the original diversity and surface productivity.…”

Section: Background On the Life Cycle Of Dinoflagellatesmentioning

confidence: 99%

“…Therefore dinoflagellates leave behind a selective record, since only cyst-forming species (approximately 10% of modern species) are represented biasing interpretations of the original diversity and surface productivity. The cyst-forming character may also be controlled by environmental fluctuations including temperature, salinity, or other stress (Gilbert and Clark, 1983), or may be the result of other life stages of a dinoflagellate or a means of survival. For the purposes of this study, the term dinocyst will be used to refer to organic-walled fossilized dinoflagellate cysts.…”

Section: Background On the Life Cycle Of Dinoflagellatesmentioning

confidence: 99%

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Upper cretaceous dinocyst assemblages from Ellef Ringnes Island, Nunavut : paleoecological changes within the Boreal Sea

Andrews¹

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Ellef Ringnes Island, in the Canadian High Arctic, preserves the sedimentary and paleoenvironmental history of the Cretaceous phase of the Sverdrup Basin. The study of dinoflagellate cysts (dinocysts) of the Late Cretaceous Kanguk Formation in combination with other fossil indicators, organic geochemistry and detailed correlation to global sea-level fluctuations provides the first stratigraphic framework for the undivided thick shaly Kanguk Formation. A new dinocyst range chart is developed consisting of mainly cosmopolitan species with a more tolerant temperature range that have invaded the Boreal realm. Extremely rich assemblages in the Boreal Sea resulted from the Cretaceous high sea level flooding terrestrial regions and delivering high supply of nutrients to shallow marine settings where plankton flourished. Ratios between benthic and pelagic dinocysts throughout the Kanguk Formation show a striking correlation to transgressive/regressive phases that are linked to global sea level. Their preservation was generally enhanced by anoxic bottom water conditions and expanded oxygen minimum zones as a result of high organic matter supply. Dinocyst radiation events took place during the late Turonian and late Santonian at times of low global sea level with incoming species preferring a shelf setting. This study demonstrates that dinocysts add a valuable proxy to depositional interpretations of the complex Cretaceous ecosystem of the Boreal Sea.i "I felt like I was seeing, woven together, the power and scale of the entire world." ) for his carbon isotope data. I would also like to thank my mother for her kind words of understanding and love through the hard times, my friends for the laughter, and my animals that bring warmth and comfort to me every day.

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Central Arctic Ocean paleoceanographic interpretations based on Late Cenozoic calcareous dinoflagellates

Cited by 38 publications

References 18 publications

Climatic effects of reduced Arctic sea ice limits in the Giss II General Circulation Model

Climatic effects of reduced Arctic sea ice limits in the Giss II General Circulation Model

Distribution of calcareous dinoflagellates from the Maastrichtian to early Miocene of DSDP Site 357 (Rio Grande Rise, western South Atlantic Ocean)

Upper cretaceous dinocyst assemblages from Ellef Ringnes Island, Nunavut : paleoecological changes within the Boreal Sea

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