Algae diversity and ecology during a summer assessment of water quality in the Abraham Lincoln Birthplace National Historical Park, USA

There were 88 species of algae and cyanobacteria observed from seven sites in the Abraham Lincoln Birthplace National Historical Park (Hodgenville, Kentucky, USA). This was the first algal investigation study in the park. There were 21 samples collected, during the summer, on 16 July 2008. Algal flora, dominated by diatoms was represented by 54 species identified (61.4% of the total), 20 species of cyanobacteria, 11 green and two charophyte algal species, and one red algal species (22.7%, 12.5%, 2.2%, and 1.1%, respectively). Benthic diatoms dominated the aquatic system with 14 species of Navicula and 12 species of Nitzschia identified, which was 15.7% and 13.5% of the total, respectively. Species tended to be site specific and 78.6% of the species were only found in two or less sites. The bioindicator methods for water quality assessment were based on species autoecology. This method was used for the first time in the USA during this study. This demonstrated that benthic and planktonic-benthic algae preferred temperate temperatures, middle-oxygenated mesotrophic waters, low-to-middle enriched by chlorides. The waters were well oxygenated, sometimes saturated by sulfides, low-alkaline, low-to-middle organic enriched, and of class 1-3 water quality with high self-purification capacity. This is very important for habitat protection and cannot be easily accomplished strictly through chemical analysis. The diversity of diatom algae not only plays a major role in the formation of algal communities and their uniqueness, but diatom algae can be a good indicator of environmental assessments and change.