Diatom assemblages from a sediment core from Lac Ba Bê in the northern mountains of Viêt Nam were analyzed at sub-decadal to sub-annual resolution to assess environmental change over the last 500 years. The most striking feature of the core is the change in diatom assemblages in the top 4 cm of the core (late 1970s/early 1980s). This section is distinguished by a flora that is characterized by a high planktic to benthic ratio and the dominant species require relatively low nutrients when compared to diatoms in the rest of the core. In particular, it marks the introduction of two Cyclotella species that become the dominant planktic species and a related decline in Aulacoseira species. The change in flora is interpreted as a possible response to a weakened Southeast Asian Monsoon beginning in the 1970s. In addition to the environmental change, a new species of Aulacoseira is described from Ba Bê.
|Advisor:||Stevens, Lora R.|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 51/05M(E), Masters Abstracts International|
|Subjects:||Paleontology, Paleoecology, Paleoclimate Science|
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