The potential of organic-walled dinoflagellate cysts for the reconstruction of past sea-surface conditions in the Southern Ocean

2007 ◽  
Vol 65 (3-4) ◽  
pp. 185-212 ◽  
Author(s):  
Oliver Esper ◽  
Karin A.F. Zonneveld
Keyword(s):  
Southern Ocean ◽  
Sea Surface ◽  
Dinoflagellate Cysts ◽  
Surface Conditions

Southwest Pacific sea surface conditions during Marine Isotope Stage 11 — Results from dinoflagellate cysts

2016 ◽  
Vol 446 ◽  
pp. 19-31 ◽  
Author(s):  
Joseph G. Prebble ◽  
Erica M. Crouch ◽  
Giuseppe Cortese ◽  
Lionel Carter ◽  
Helen Neil ◽  
...  
Keyword(s):  
Sea Surface ◽  
Marine Isotope Stage ◽  
Dinoflagellate Cysts ◽  
Surface Conditions ◽  
Southwest Pacific

scholarly journals Climate Change in the Southern Ocean During the Middle Eocene to Early Oligocene: A Palynological Perspective

2021 ◽  
Author(s):  
◽  
Claire Andrea Storkey
Keyword(s):  
Southern Ocean ◽  
Middle Eocene ◽  
Climatic Changes ◽  
Weddell Sea ◽  
Sea Surface ◽  
Total Abundance ◽  
Dinoflagellate Cysts ◽  
Early Oligocene ◽  
Cooling Effects ◽  
Terrestrial Material

<p>The Antarctic and Southern Ocean is an area that was greatly affected by climatic changes during the Middle Eocene to Early Oligocene (E/O). This study aims to document climate-induced changes of the marine palynomorphs (mostly dinoflagellate cysts) by developing a Circum-Antarctic biozonation, and establishing the distribution and effects of cooling on the palynomorph assemblages and the palaeoenvironment. Samples were obtained from four sites by the Ocean Drilling Program (ODP) and Deep Sea Drilling Project (DSDP) and the palynological content was analyzed. These sites were selected as they may record effects of circulation changes and cooling trends, reflecting climate changes. ODP site 696B, was inner neritic and located in the South Orkney microcontinent, Weddell Sea. The other three sites were pelagic with ODP 699A located on the Northeast Georgia Rise, Falklands, ODP 748B located in the Western part of the Raggart Basin, Kerguelen Plateau and DSDP 277 located in Cathedral Depression on the Southern Campbell Plateau. From this analysis a comprehensive record of the local climatic transitions was ascertained, utilising assemblages of fossil organic-walled dinoflagellate cysts (dinocysts), acritarchs, prasinophyte algae, microforaminiferal linings, scoledonts and terrestrial material. The establishment of a standard nannofossil biostratigraphy provided a temporal framework of the marine palynomorphs in each site. Key dinocyst datums recognised as first or last occurrences that correlated reliably between sites, were compared with the nannofossil zones of each site. The purpose was to provide a Middle Eocene/Early Oligocene dinocyst biostratigraphy that temporally constrains the assemblages. Six primary datums and two secondary datums resulted, which lead to the recognition of four biozones and established a new biozonation in the Southern Ocean. The zones identified various dinocyst events, giving an indication of their probable palaeoenvironments. The Circum-Antarctic distribution pattern of palynomorph assemblages was documented in each site as a total abundance of grains per gram. The ranges and composition of palynomorph assemblages of each site were displayed as a percentage of total abundance. To document any cooling effects the dinocysts were separated into Gonyaulacoid or Peridinioid assemblages to best illustrate their preferred palaeoenvironment. Key findings showed that the pelagic and inner neritic sites differed greatly. Site 696B was the most climatically stable site and dominated by Peridinioid dinocysts which are predominantly heterotrophic. They are most common in an inner neritic palaeoenvironment, but are also present in nutrient upwellings and eutrophic surface waters with lower sea surface temperatures. Terrestrial material dominates all marine palynomorphs in this site which was shallow and warm with few changes up to the E/O boundary ~33.7 Ma, but became more variable in the Early Oligocene. In comparison, the pelagic sites (699, 748B, 277) were unstable, with missing or condensed sediments and no palynomorphs present at differing times. They were mostly dominated by Gonyaulacoid dinocysts, which are autotrophs and generally located in outer neritic to open ocean palaeoenvironments. The non dinocysts of Prasinophyte algae and Leiosphaeridia palynomorphs appeared in higher abundances in the pelagic sites than in the inner neritic sites. Specific dinocyst markers identified temperature changes within the pelagic sites, subsequently highlighting the climatic changes that occurred during the Middle Eocene/Early Oligocene. From ~46 Ma the pelagic sites recorded conditions that were oceanic and cooler. Between ~44 - ~41.5 Ma, a warming in site 748B indicated enhanced stratification and elevated nutrient availability. This was not the case in site 696B and may be due to warm temperatures already present. From ~41.4 Ma the pelagic sites showed that the palaeoenvironment continued to cool, indicated by the presence of Leiosphaeridia and Prasinophyte algae. The palaeoenvironment was oceanic with upwelling and offshore sea surface productivity, illustrated by the Gonyaulacoid and Peridinioid dinocysts present. During the Late Eocene from ~37 Ma a transitional and changeable palaeoenvironment was shown by the high numbers of Operculodinium spp present in sites 696B and 277. From ~33.7 Ma (E/O boundary) in the pelagic sites, most Peridinioid dinocysts had disappeared and very few Gonyaulacoid dinocysts were present. In contrast the inner neritic site (696B) Peridinioid dinocysts were still dominant, and a more gradual disappearance of all the marine palynomorphs was evident.</p>

scholarly journals Climate Change in the Southern Ocean During the Middle Eocene to Early Oligocene: A Palynological Perspective

2021 ◽  
Author(s):  
◽  
Claire Andrea Storkey
Keyword(s):  
Southern Ocean ◽  
Middle Eocene ◽  
Climatic Changes ◽  
Weddell Sea ◽  
Sea Surface ◽  
Total Abundance ◽  
Dinoflagellate Cysts ◽  
Early Oligocene ◽  
Cooling Effects ◽  
Terrestrial Material

<p>The Antarctic and Southern Ocean is an area that was greatly affected by climatic changes during the Middle Eocene to Early Oligocene (E/O). This study aims to document climate-induced changes of the marine palynomorphs (mostly dinoflagellate cysts) by developing a Circum-Antarctic biozonation, and establishing the distribution and effects of cooling on the palynomorph assemblages and the palaeoenvironment. Samples were obtained from four sites by the Ocean Drilling Program (ODP) and Deep Sea Drilling Project (DSDP) and the palynological content was analyzed. These sites were selected as they may record effects of circulation changes and cooling trends, reflecting climate changes. ODP site 696B, was inner neritic and located in the South Orkney microcontinent, Weddell Sea. The other three sites were pelagic with ODP 699A located on the Northeast Georgia Rise, Falklands, ODP 748B located in the Western part of the Raggart Basin, Kerguelen Plateau and DSDP 277 located in Cathedral Depression on the Southern Campbell Plateau. From this analysis a comprehensive record of the local climatic transitions was ascertained, utilising assemblages of fossil organic-walled dinoflagellate cysts (dinocysts), acritarchs, prasinophyte algae, microforaminiferal linings, scoledonts and terrestrial material. The establishment of a standard nannofossil biostratigraphy provided a temporal framework of the marine palynomorphs in each site. Key dinocyst datums recognised as first or last occurrences that correlated reliably between sites, were compared with the nannofossil zones of each site. The purpose was to provide a Middle Eocene/Early Oligocene dinocyst biostratigraphy that temporally constrains the assemblages. Six primary datums and two secondary datums resulted, which lead to the recognition of four biozones and established a new biozonation in the Southern Ocean. The zones identified various dinocyst events, giving an indication of their probable palaeoenvironments. The Circum-Antarctic distribution pattern of palynomorph assemblages was documented in each site as a total abundance of grains per gram. The ranges and composition of palynomorph assemblages of each site were displayed as a percentage of total abundance. To document any cooling effects the dinocysts were separated into Gonyaulacoid or Peridinioid assemblages to best illustrate their preferred palaeoenvironment. Key findings showed that the pelagic and inner neritic sites differed greatly. Site 696B was the most climatically stable site and dominated by Peridinioid dinocysts which are predominantly heterotrophic. They are most common in an inner neritic palaeoenvironment, but are also present in nutrient upwellings and eutrophic surface waters with lower sea surface temperatures. Terrestrial material dominates all marine palynomorphs in this site which was shallow and warm with few changes up to the E/O boundary ~33.7 Ma, but became more variable in the Early Oligocene. In comparison, the pelagic sites (699, 748B, 277) were unstable, with missing or condensed sediments and no palynomorphs present at differing times. They were mostly dominated by Gonyaulacoid dinocysts, which are autotrophs and generally located in outer neritic to open ocean palaeoenvironments. The non dinocysts of Prasinophyte algae and Leiosphaeridia palynomorphs appeared in higher abundances in the pelagic sites than in the inner neritic sites. Specific dinocyst markers identified temperature changes within the pelagic sites, subsequently highlighting the climatic changes that occurred during the Middle Eocene/Early Oligocene. From ~46 Ma the pelagic sites recorded conditions that were oceanic and cooler. Between ~44 - ~41.5 Ma, a warming in site 748B indicated enhanced stratification and elevated nutrient availability. This was not the case in site 696B and may be due to warm temperatures already present. From ~41.4 Ma the pelagic sites showed that the palaeoenvironment continued to cool, indicated by the presence of Leiosphaeridia and Prasinophyte algae. The palaeoenvironment was oceanic with upwelling and offshore sea surface productivity, illustrated by the Gonyaulacoid and Peridinioid dinocysts present. During the Late Eocene from ~37 Ma a transitional and changeable palaeoenvironment was shown by the high numbers of Operculodinium spp present in sites 696B and 277. From ~33.7 Ma (E/O boundary) in the pelagic sites, most Peridinioid dinocysts had disappeared and very few Gonyaulacoid dinocysts were present. In contrast the inner neritic site (696B) Peridinioid dinocysts were still dominant, and a more gradual disappearance of all the marine palynomorphs was evident.</p>

scholarly journals Middle Jurassic-Early Cretaceous high-latitude sea-surface temperatures from the Southern Ocean

2011 ◽  
Vol 7 (2) ◽  
pp. 1339-1361 ◽  
Author(s):  
H. C. Jenkyns ◽  
L. Schouten-Huibers ◽  
S. Schouten ◽  
J. S. Sinninghe Damsté
Keyword(s):  
Southern Ocean ◽  
Early Cretaceous ◽  
Middle Jurassic ◽  
Climatic Conditions ◽  
Sea Surface ◽  
Polar Regions ◽  
Polar Ice ◽  
Surface Conditions ◽  
The Earth

Abstract. Although a division of the Phanerozoic climatic modes of the Earth into "greenhouse" and "icehouse" phases is widely accepted, whether or not polar ice developed during the relatively warm Jurassic and Cretaceous Periods is still under debate. In particular, there is a range of isotopic and biotic evidence that favours the concept of discrete "cold snaps", marked particularly by migration of certain biota towards lower latitudes. Extension of the use of the palaeotemperature proxy TEX86 back to the middle Jurassic indicates that relatively warm sea-surface conditions (26–30 °C) existed from this interval (~160 Ma) to the Early Cretaceous (~115 Ma) in the Southern Ocean. The Jurassic and Cretaceous "cold snaps" represent falls of only a few degrees. Belemnite δ18O data give palaeotemperatures that are consistently lower by ~14 °C than does TEX86 and these molluscs likely record conditions below the thermocline. Such long-term warm climatic conditions would only be compatible with the existence of continental ice if appreciable areas of high altitude existed on Antarctica, and/or in other polar regions, during the Mesozoic Era.

Constraining Holocene sea-surface conditions in the south-western Black Sea using dinoflagellate cysts

2012 ◽  
Vol 27 (8) ◽  
pp. 835-843 ◽  
Author(s):  
L. R. Bradley ◽  
F. Marret ◽  
P. J. Mudie ◽  
A. E. Aksu ◽  
R. N. Hiscott
Keyword(s):  
Black Sea ◽  
Sea Surface ◽  
Dinoflagellate Cysts ◽  
The South ◽  
Surface Conditions

Late-Holocene sea-surface conditions offshore Newfoundland based on dinoflagellate cysts

The Holocene ◽  
2011 ◽  
Vol 21 (4) ◽  
pp. 539-552 ◽  
Author(s):  
Sandrine Solignac ◽  
Marit-Solveig Seidenkrantz ◽  
Catherine Jessen ◽  
Antoon Kuijpers ◽  
Anja K. Gunvald ◽  
...  
Keyword(s):  
Late Holocene ◽  
Sea Surface ◽  
Dinoflagellate Cysts ◽  
Surface Conditions

Palynomorph distribution in Recent sediments from the Labrador Sea

1994 ◽  
Vol 31 (1) ◽  
pp. 115-127 ◽  
Author(s):  
André Rochon ◽  
Anne de Vernal
Keyword(s):  
Surface Water ◽  
Primary Productivity ◽  
Water Masses ◽  
Sea Surface ◽  
Labrador Sea ◽  
Dinoflagellate Cysts ◽  
Eastern Canada ◽  
Long Distance ◽  
Surface Conditions ◽  
Dinoflagellate Cyst

Surface sediments from the Labrador Sea and Baffin Bay have been examined for their palynomorph content. Pollen and spore assemblages reflect the vegetation zones of eastern Canada, although long-distance atmospheric transport results in over-representation of Pinus and spores. A linear decrease of pollen input is observed with distance from the source vegetation; the abyssal domain receives less than 2% of the initial input. The abundance of dinoflagellate cysts reflects a relatively high primary productivity in surface water masses which seems proportional to the benthic productivity, as shown by the concentrations of organic linings of foraminifers. The relative abundance of dinoflagellate cyst taxa and principal component analysis led to the definition of three assemblages that can be related to sea-surface conditions and current pattern. The modern distribution of dinoflagellate cysts was used to interpret assemblages recovered in five box cores from the deep Labrador Sea. Results reveal important changes in sea-surface conditions during the Holocene. At the end of the last glacial period, the productivity in surface waters was sparse, notably on the continental slope off southwest Greenland. Shortly after the deglaciation, the primary productivity increased, probably due to the improvement of sea-surface conditions. At about 5000 BP, the dinoflagellate cyst concentrations and fluxes reach maximum values, and the assemblages are marked by the augmentation of Nematosphaeropsis labyrinthus relative to Operculodinium centrocarpum. This trend is associated with a cooling and the increased influence of the inner component of the Greenland Current in surface water masses of the Labrador Sea. It marks the establishment of modern conditions in the basin.

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