Increased plankton diversity and community similarity in artificially heated lakes

We collected lake water samples from a set of five heated lakes (Goslawskie, Lichenskie, Patnowskie, Slesinskie and Mikorzynskie) and five unheated (hereafter “control”) lakes (Budzislawskie, Goplo, Skulskie, Skulska Wies and Suszewskie) located near the city of Konin in central Poland. Each lake was sampled four times: in winter, spring, summer and autumn 2020. Two liters of surface water were collected at each sampling event and passed through a glass fiber filter (Whatmann GF/F, 25 mm diameter, 0.7 µm pore size) using vacuum filtration at 200 mbar. DNA was extracted from the whole pulverized filter using the NucleoSpin Plant II extraction kit (Machery-Nagel, Düren, Germany) following the manufacturer's protocol. All samples were amplified using three primer sets (hereafter, DIV4, EUK15 and CHY) that target a small region of either the 18S (DIV4 and EUK15) or 28S (CHY) rRNA genes of eukaryotes. Amplicons were then pooled in equimolar amounts and sequenced on an Illumina MiSeq using a v3 sequencing kit (600 cycles). The data offers a great opportunity to address potential long-term effects of warming on freshwater communities across seasons and trophic levels.