Vampyrellids are immortal. At least if not starved. These highly effective predators have survived extreme climate changes over millennia, are populating fresh- and salt water and even periglacial soil in abundance. While shaping microbial communities, these protists are playing a pivotal role in ocean health and climate regulation. In this book their structure and life cycle is revealed in stunning detail by Zeiss images allowing to witness the special abilities of shape-shifting, their applied different hunting strategies and their synchronized feeding and hatching. Phylogenetic analysis and recent laboratory data enhance the translational power of the presented findings and account for telling insights into the lately discovered, highly resilient vampire amoeba PGC 2.2*. Tolerating temperature and salinity changes, various prey and artificial storage media, PGC 2.2 could be long-term cultured in laboratories in order to investigate into their biotechnological active agent eligibility. They might be a game changer when addressing recent ecological problems by facilitating element cycling and fighting organisms containing microplastic. The search for new vampyrellids is ongoing. * New marine vampyrellid amoeba PGC 2.2 genus et species novel

Text sample: Chapter 2, Materials and Methods: In the following chapter, the setup of the sample provenience, subculturing and the food selectivity experiment will be described, followed by the salinity, temperature, and light experiment. The procedures leading to the lineage determination and classification of PGC 2.2 vampire amoebae are consecutively detailed, while the description of the used SOP and devices are closing this chapter. 2.1, Sample provenience and subculturing: The natural marine sample used in this study was taken on May 6th 2016 at low tide from the upper tidal pools in Peggy's Cove at St. Margarets Bay in Nova Scotia, Canada (44°29'48.8 N 63°55'03.7 W) which are also the eponym of PGC 2.2. gen. et sp. Nov. The salinity of the sample was measured by a hand-held refractometer (VWR). Further details on the natural sample documented immediately after its collection are displayed in Appendix . After the collecting, vampyrellid digestive cysts and single trophozoites were isolated from the natural sample and transferred to a cell culture flask. To prepare the sample for transport via plane to Germany, sterile medium (F/2, F/8) was added, which is known to stimulate the growth of indigenous marine algae (Shyam Kumar, S., & Saramma, A. V. 2018). The storage media F/2 and F/8 differ in their dilution degree, corresponding to Guillard & Ryther (1962) protocol. 2.1.1, Monitoring culture growth: Secondary-cultures were checked several times a week. Whenever live prey was depleted, they were subcultivated into new flasks using fresh algal material grown in F/8 without any additional change in environmental influencing factors like temperature or light. The health of all cultures was monitored for five months by recording the presence of active and immobile vampire amoebae, as well as empty digestive cysts, bacteria, and algae growth. Whenever the bottom of the culture flask was completely overgrown by algae and/or the medium swarming with bacteria, the environment was deemed unhealthy” for further growth of PGC 2.2 and trophozoites and cysts were transferred to a new flask. 2.1.2, Tackling risks: The described procedure was altered when the number of PGC 2.2 seemed in drastic decline: different environmental parameters were subsequently changed to recover PGC 2.2 population. Among the first-hand rescue procedures was an imposed change of temperature, as it is well known that marine vampire amoebae prefer lower to room temperature, being closer to their natural habitat. To buffer the difference between forecasted and actual demand levels of food, a safety stock of various algae were stored in the cold room at 10 °C. It also allowed mitigating the risk of a stock out when there is a sudden need to subculture due to an unexpected population expansion occurred.

• marine ecosystem

• protist

• vampyrellid amoeba

• life cycle

• microscopic images

• phylogenetic analysis

• bioremediation

• climate regulation

Anna Renée Lingner has studied and worked in Canada, Germany and New Zealand on the rim of oceans. She recently assumes teaching responsibilities in Germany.