Diatom assemblages from ARA2B-1A taken in the Chukchi Sea shelf were analyzed to reconstruct paleoenvironmental changes during the last 10 ka BP. The main factors controlling the distribution of diatom in the Chukchi Sea are the relatively warm and nutrient-rich Pacific water inflow after the opening of the Bering Strait. Based on the selected diatoms, three diatom assemblage zones are identified. The diatom assemblage zone I shows a rare or very low abundance, which corresponds to the early Holocene (10–8 ka BP). The diatom assemblage zone II corresponds to the mid-to-late Holocene (8–2 ka BP). It is a seasonal sea-ice environment with relatively abundant diatom valves and Chaetoceors resting spores, as well as sea-ice species, cold-water species, coastal species, and upwelling species. The diatom assemblage zone III corresponds to the late Holocene (2–0 ka BP), and the the sea-ice species generally decreased compared to zone II, while the coastal species Paralia sulcata occurred abundantly. In particular, the Thalassiosira antarctica, a cold-water species, increased distinctly during this time interval. After ∼2 ka BP, T. antarctica rapidly increased while sea-ice species rarely appeared, indicating limited open-marine environments. In particular, after 1 ka BP, T. antarctica decreased while the sea-ice species increased, suggesting that the sea-ice increased again before the recent global warming of the Arctic, the late Holocene.

对楚科奇海陆架中采集的 ARA2B-1A 硅藻组合进行了分析，以重建过去 10 ka BP 期间的古环境变化。控制楚科奇海硅藻分布的主要因素是白令海峡开放后相对温暖且营养丰富的太平洋海水流入。根据选定的硅藻，确定了三个硅藻组合区。硅藻组合区I显示出罕见或非常低的丰度，对应于全新世早期（10-8 ka BP）。硅藻组合带II对应于全新世中晚期（8~2 ka BP）。属季节性海冰环境，硅藻瓣和角毛藻休眠孢子相对丰富，还有海冰物种、冷水物种、沿海物种和上升流物种。硅藻组合Ⅲ区对应于全新世晚期（2~0 ka BP），海冰种类较Ⅱ区普遍减少，而沿海物种Paralia sulcata大量出现。特别是冷水物种南极海链藻在此时间段内明显增加。约2 ka BP后，南极洲T. antarctica迅速增加，而海冰物种很少出现，表明开放海洋环境有限。特别是，在1ka BP之后，南极洲T. antarctica减少，而海冰种类增加，这表明在最近的北极全球变暖（全新世晚期）之前，海冰再次增加。