Data for: Waterborne transmission largely contributes to the epidemiology of a plankton parasite

Understanding how parasites spread is crucial for preventing infections and predicting epidemic dynamics. These efforts are especially challenging for environment-borne parasites, because transmission is host density independent. We monitored the dynamics of Pasteuria ramosa, a common bacterial parasite of zooplankton (Daphnia magna) with prolonged free-living transmission stages (spores). Spores are released into the sediment from decaying host cadavers, forming a spore bank. Transmission is believed to happen predominantly from sediment to host, though recent work has challenged this assumption and suggested that transmission may also happen in the water column. We collected water samples during an epidemic and found infectious spore levels in the water, thus confirming this transmission pathway. Water column spore concentration correlated with epidemic dynamics, suggesting that this pathway contributes to disease dynamics. We demonstrate experimentally that spores have a low sedimentation rate, suggesting that once suspended in the water, they remain in suspension for extend periods. We exclude that spores are released in the free water through macroinvertebrate predation or decomposition of dead Daphnia as they sink, thus suggesting that bio- or water-perturbation transfers spores from the sediment to the water. Water birds and large zooplankton populations are potential bioturbators in this fishless pond. This research contributes insights into the transmission of environment-borne parasites, emphasizing the importance of considering the physical environment and ecological community.We present here data sets from our field collections, which include information on the densities of all zooplankton detected over two summers as well as the infection status of Daphnia magna with Pasteuria ramosa, which was collected weekly using a plankton net, and waterbird counts which were made across the whole pond for one field season. We also present experimentla data for each of these field seasons, in which water from the pond was taken back to the lab and exposed to a range of Daphnia genotypes to assess its infectivity. We also present data on two additional experiments: one in which spores at a known concentration were mixed into water and their sedimentation rate was measured, and one in the sinking rate of Dead Daphnia was measured. Data sets are all uploaded as csv files, with a Readme txt document describing each data set and column included. We also include all R code necessary to reproduce the results and figures presented in our manuscript.