Distribution of Chaetoceros resting spores in modern peri-Antarctic sediments
- 標題
- Distribution of Chaetoceros resting spores in modern peri-Antarctic sediments
- 作者
- Xavier Crosta, Jean-Jacques Pichon, Monique Labracherie
- 文件屬性
- 國外期刊
- 知識分類
- 基礎研究
- 出版年
- 1997
- 刊名
- Marine Micropaleontology
- 關鍵字
- Southern Ocean; biogeography; diatoms; Chaetoceros resting spores
- 點閱數
- 7358
摘要
One hundred and sixty-five surface sediment samples from the Southern Ocean were examined for distribution and relative abundance of Chaetoceros resting spores. The contribution of resting spores to the total diatom assemblage ranges from 0% in the Subantarctic Zone to 95% in the Antarctic Peninsula sector. On the basis of both absolute and relative abundances four ‘biogeographic’ zones are distinguished: (1) the Antarctic Peninsula sector, (2) the Embayment Systems (Ross Sea and Weddell Sea), (3) the Continental Shelf zone (water depth < 2000 m) and (4) the Deep Ocean (water depth > 2000 m).
Chaetoceros resting spores abundance reaches up to 900 × 106 valves/g of dry sediment in the Gerlache Strait, southwest of the Antarctic Peninsula. The hydrology of this region is characterized by an intense stratification of the water column due to sea-ice meltwater inputs, continental glacial runoffs and thermal warming of the surface water layer. The availability of nutrients, the lack of vertical mixing in those surface waters having low salinity (< 30 parts per mil) and relatively high temperature (> 2.4 °C) is thought to be the main pre-condition for development of large Chaetoceros species blooms. We propose that increased relative abundances of Chaetoceros resting spores in fossil diatom assemblages from the Southern Ocean can therefore be used as tracers of water-column stratification due to glacial melt water.
Chaetoceros resting spores abundance reaches up to 900 × 106 valves/g of dry sediment in the Gerlache Strait, southwest of the Antarctic Peninsula. The hydrology of this region is characterized by an intense stratification of the water column due to sea-ice meltwater inputs, continental glacial runoffs and thermal warming of the surface water layer. The availability of nutrients, the lack of vertical mixing in those surface waters having low salinity (< 30 parts per mil) and relatively high temperature (> 2.4 °C) is thought to be the main pre-condition for development of large Chaetoceros species blooms. We propose that increased relative abundances of Chaetoceros resting spores in fossil diatom assemblages from the Southern Ocean can therefore be used as tracers of water-column stratification due to glacial melt water.