Indicative value and training set of freshwater organic-walled algal palynomorphs (non-pollen palynomorphs)

Only a few studies have related modern non-pollen palynomorphs to environmental variables, limiting the development of non-pollen palynomorphs training sets. Here, we perform substantial groundwork by developing a training set for freshwater organic-walled algal palynomorphs. We sampled surface sediments from 78 waterbodies across Latvia in north-eastern Europe with the aim of gaining infor-mation on the distribution and diversity of algal palynomorphs. We analysed the preferred living con-ditions (water and sediment properties) of algal palynomorphs in conjunction with climate and catchment characteristics (Quaternary sediment type, landscape usage, and composition). In total, 94 species/taxa belonging to four phyla (Cyanobacteria, Chlorophyta, Charophyta, and Ochrophyta) were identified. By applying statistical and descriptive analyses, we showed the indicative value of algal palynomorphs along various gradients. Using the established training set, we for the first constructed organic-walled algal palynomorphs-based pH and electric conductivity reconstructions for two lakes where natural and anthropogenic variability was recognised. Freshwater algal palynomorphs assem-blages constrained by environmental and climatic variables open new horizons for further non-pollen palynomorphs qualitative and quantitative research. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study investigates and analyzes the distribution, diversity, and relationship with environmental variables of freshwater organic-walled algal palynomorphs by developing a training set. By analyzing the properties of water and sediment, as well as climate and catchment characteristics, the indicative value of algal palynomorphs along different gradients is revealed. Reconstruction of pH and electric conductivity for two lakes using the established training set provides possibilities for further non-pollen palynomorph research.