As the deep sea alone covers over 50% of the Earth’s surface and represents the largest benthic system, the assessment of deep-sea megafauna communities is of great importance. However, even today the number of studies investigating this system is small and is further hampered by the resource- and time-consuming nature of traditional manual surveys. Therefore, it is of great importance to find efficient sampling methods and op...

Seamounts are thought to function as hotspots of megafauna diversity due to their topology and environmental characteristics. However, assessments of megafauna communities inhabiting seamounts, including diversity and density, are scarce. In this study, we provide megafauna diversity and density estimates for a recently discovered, not yet characterized seamount region (Boetius seamounts) west of Cape Verde (N17° 16′, W29° 26′...

Amphibian clutches are colonized by diverse but poorly studied communities of micro-organisms. One of the most noted ones is the unicellular green alga, Oophila amblystomatis , but the occurrence and role of other micro-organisms in the capsular chamber surrounding amphibian clutches have remained largely unstudied. Here, we undertook a multi-marker DNA metabarcoding study to characterize the community of algae and other micro...

Locomotion is considered to be the main form of expression of ciliate behaviour regarding their overall life activity. But how ciliates behave under deep-sea conditions is still unclear. Data on the occurrence of ciliates in the deep sea are scarce and mostly based on molecular studies. We isolated three different ciliates, Aristerostoma sp., Euplotes dominicanus and Pseudocohnilembus persalinus from two stations located in ab...

One of the most prominent manifestations of the ongoing climate warming is the retreat of glaciers and ice sheets around the world. Retreating glaciers result in the formation of new ponds and lakes, which are available for colonization. The gradual appearance of these new habitat patches allows us to determine to what extent the composition of asexual Daphnia (water flea) populations is affected by environmental drivers vs. d...

Extreme environmental conditions in the deep sea hamper access to protist communities. In combination with the potentially highly diverse species composition, it demands a wide range of methods to be applied at the same time to guarantee a high resolution of quantitative and qualitative studies of deep-sea heterotrophic flagellates (HF). Within this study, we present a possible combination of several culture-independent and cu...

Climate warming is discussed as a factor that can favour the success of invasive species. In the present study, we analysed potential fitness gains of moderate warming (3 °C above field temperature) on the invasive clam Corbicula fluminea during summer and winter. The experiments were conducted under seminatural conditions in a bypass‐system of a large river (Rhine, Germany). We showed that warming in late summer results in a...

We tested the role of immigration from the plankton on the structure of local surface‐associated communities of ciliates and heterotrophic flagellates (HF) in flow cells fed with fresh riverine water (Rhine, Germany). By applying size fractionation, we reduced the immigration potential of HF from the plankton in mature, pregrown biofilms by 93%, and observed no significant effects on the abundance and taxonomic composition of...

The question of whether deterministic chaos occurs in natural populations has been discussed since the 1970s following the discovery that simple population models can generate chaotic dynamics. Natural populations undergo a diverse mixture of deterministic and stochastic processes that define population dynamics. In most habitats populations are also exposed to changes in biotic and abiotic parameters. Models predict that shif...

We investigated the role of a macrograzer (the filter feeding mussel Dreissena polymorpha ) in mediating effects of high summer temperatures on the dominant components of natural river plankton (i.e., bacteria, algae, and heterotrophic flagellates) in flow channel experiments. Effects of adaptation (by comparing mussels from a southern and a northern population) and thermal acclimation of the mussels were considered. Both hete...