Pollen morphology of selected tundra plants from the high Arctic of Ny-(A)lesund, Svalbard

Documenting morphological features of modem pollen is fundamental for the identification of fossil pollen, which will assist researchers to reconstruct the vegetation and climate of a particular geologic period. This paper presents the pollen morphol- ogy of 20 species of tundra plants from the high Arctic of Ny-Alesund, Svalbard, using light and scanning electron microscopy. The plants used in this study belong to 12 families： Brassicaceae, Caryophyllaceae, Cyperaceae, Ericaceae, Juncaceae, Papav- eraceae, Poaceae, Polygonaceae, Ranunculaceae, Rosaceae, Salicaceae, and Scrophulariaceae. Pollen grain shapes included： spher- oidal, subprolate, and prolate. Variable apertural patterns ranged from 2-syncolpate, 3-colpate, 3-（-4）-colpate, 3-（-5）-colpate, 3-colporate, 5-poroid, ulcerate, ulcus to pantoporate. Exine ornamentations comprised psilate, striate-perforate, reticulate, mi- croechinate, microechinate-perforate, scabrate, granulate, and granulate-perforate. This study provided a useful reference for com- parative studies of fossil pollen and for the reconstruction of paleovegetation and paleoclimate in Svalbard region of Arctic.     

The changes of pigment contents and their environmental implications in the lake sediments of Ny-(A)lesund, Svalbard, the Arctic

According to palaeoclimatic and modern instrumental data, numerous studies have indicated that the Arctic climate has undergone a significant warming during the past 100 years, and this may lead to significant impact on the fragile lake ecosystem. In this study, we collected a lake sediment core from the Ny-(A)lesund of Svalbard and determined the concentrations of four pigments including chlorophyll derivatives, total carotenoids, oscillaxanthin and myxoxanthophyll in the sediments. Combined with other physical and chemical proxies such as calcium carbonate, total organic carbon, biogenic silicon etc., we have reconstructed the historical changes of lacustrine primary productivity in Ny-(A)lesund, especially for the past 100 years. The results showed that during the period of Little Ice Age (LIA), the climate was unfavorable for the growth of the lake algae, and thus the lacustrine productivity declined. This result was supported by the relatively low contents of pigment and biogenic silica in the sediments. In contrast, the contents of total organic carbon (TOC) and sediment pigments increased significantly in the upper 5 cm (~1890AD), reflecting the rapid growth of the lake algae, thus the great increase of lacustrine primary productivity, corresponding to the warming climate after LIA. However, the biogenic silica in the upper sediments still had a relatively low level, and this might be related to the growth competition with other algae species. Over the past 100 years, the ratio of Osc/Myx in the sediments decreased continuously, indicative of durative increase of myxoxanthophyll in blue-green algal pigments, and this might imply that the human activity had enhanced the nutrition level of the lake in the Arctic region.