Towards understanding the abundance of non-pollen palynomorphs: A comparison of fossil algae, algal pigments and sedaDNA from temperate lake sediments

Abstract

Given the increased interest in non-pollen palynomorphs (microscopic objects other than pollen identified from the pollen slides) in palaeoecological studies, it is necessary to seek a deeper understanding how reliable the obtained results are. By combining quantitative information of algal pigments and phylotaxonomical resolution from sedimentary ancient DNA (sedaDNA), we validate the richness and abundance of aquatic non-pollen palynomorphsfossil algae, in the sediment of a small temperate lake. For the first time, fossil and sedaDNA algae data were combined in a composite data-set and algal turnover rates in time were reconstructed for the last 14,500 years. This comparison will serve as an indication to what extent fossil algae can be used to answer different research questions and to reveal if it is reliable to base palaeoecological interpretation solely on fossil algae identified from the pollen slides.

Lake Sedimentary DNA Research on Past Terrestrial and Aquatic Biodiversity: Overview and Recommendations

“…DNA from aquatic biota compared to lipids, pigments and subfossils: The sedaDNA signal of past aquatic biota has mainly been compared to lipid, pigment, or subfossil (such as diatom frustules) records. The current view is that the DNA information in sediments degrades faster than pigments or lipids, although significant positive correlations have been observed between these different proxies [18,72,77,[137][138][139][140][141]. Studies comparing diatom diversity retrieved from sediment using morphological and genetic approaches consistently show that beta-diversity values obtained from both methods were highly comparable (i.e., the turnover is similar), whereas alpha-diversity values and taxonomic assignment datasets were not [45,[142][143][144][145][146][147].…”

Environmental palaeogenomic reconstruction of an Ice Age algal population

“…Nannochloropsis could be detected in modern sedimentary DNA data from five north Norwegian localities 51 (Supplementary Table 6 ). In addition to LGM Andøya 41 , Nannochloropsis has either been previously reported, or unreported, but present based on our re-analysis, in eight sed aDNA records from Greenland 52 , St. Paul Island, Alaska, USA 9 , 11 , Alberta and British Columbia, Canada 10 , Latvia 53 , Qinghai, China 54 and Svalbard 50 , 55 (Supplementary Data 7 and Supplementary Fig. 12 ).…”

Effect of Soil Characteristics on Arsenic Accumulation in Phytolith of Gramineae (Phragmites japonica) and Fern (Thelypteris palustris) Near the Gilgok Gold Mine

“…The plant shoot part was rinsed with distilled water and dried in an oven at 50 • C. Then, 0.5 g of plant samples were digested by 5 mL of HNO 3 and 3 mL of H 2 O 2 in a microwave (Milestone, Italy) for 30 min, 180 • C at 2.45 Ghz and 12.25 cm [29]. Because the research focused on phytolith, the digested solution was centrifuged, and the pellet was digested with 10% KOH [30] until the solution was clean. The two solutions were combined, filtered, and analyzed by ICP-MS (Agilent, Santa Clara, CA, USA).…”

“…The remaining pellets were dried and weighed to know the ratio of phytoliths in the plant. The extracted phytoliths were digested with 10% KOH [30] by microwave (Milestone, Italy) digestion at 180 • C at 2.45 Ghz and 12.25 cm until the solution was clean. The digested solution was acidified with nitric acid, filtered, and analyzed by ICP-MS (Agilent, Santa Clara, CA, USA) at 75 amu.…”