Description: Transparent exopolymer particles (TEP) are a class of marine gel particles and important links between surface ocean biology and atmospheric processes. Derived from marine microorganisms, these particles can facilitate the biological pumping of carbon dioxide to the deep sea, or act as cloud condensation and ice nucleation particles in the atmosphere. Yet, environmental controls on TEP abundance in the ocean are poorly known. Here, we investigated some of these controls during the first multiyear time-series on TEP abundance for the Fram Strait, the Atlantic gateway to the Central Arctic Ocean. Data collected at the Long-Term Ecological Research observatory HAUSGARTEN during 2009 to 2014 indicate a strong biological control with highest abundance co-occurring with the prymnesiophyte Phaeocystis pouchetii. Higher occurrence of P. pouchetii in the Arctic Ocean has previously been related to northward advection of warmer Atlantic waters, which is expected to increase in the future. Our study highlights the role of plankton key species in driving climate relevant processes; thus, changes in plankton distribution need to be accounted for when estimating the ocean’s biogeochemical response to global change.

Description: Validated prototypes of new and enhanced biogeochemical and biological sensors and instruments. Validation will be undertaken in the laboratory, in test scenarios, and by deployment in operational conditions

Description: Dinoflagellate species of the genus Dinophysis have become target organisms for surveillance and monitoring of microalgae as they may produce potent diarrhetic shellfish toxins and therefore have negative socio-economic impacts. The formation of Dinophysis blooms as well as toxin composition and cellular toxin content depends on several multifactorial climate and environmental drivers and it might be expected that the occurrence of toxic events becomes more intense, widespread, frequent and unexpected in future decades due to climate variability. Conventional methods for the identification of microalgae e.g. microscopy, still have some deficiencies as they are very time-consuming and need special knowledge and experience, especially in case of difficult morphological species distinction. Standard quantification methods also might fail to detect and determine Dinophysis species due to their typically low cell densities and their spatial heterogeneity (=patchiness). Therefore innovative technologies for environmental monitoring of toxic microalgae are needed to prevent humans and aquatic environments from toxic threats and damage. We analysed the occurrence, abundance and dispersal of toxic dinoflagellate species in Nordic seas and the Arctic Ocean. Genetic analyses included a modular composed autonomous rRNA biosensor approach that allows rapid, precise and economically efficient high-resolution quantification and identification of microalgae in aquatic environments. Next generation sequencing (Illumina) was used to get additional information on distributional patterns of the most common dinoflagellate species in the observation area.

Description: Microalgae are the major producers of biomass and organic compounds in the aquatic environment. Among them there are toxic species (mainly dinoflagellates) known to have the potential to form Harmful Algal Blooms, the so called HABs. HABs are occurring more often and at new locations. In general, knowledge about biogeographic distribution of harmful algae in the northern hemisphere is limited and patchy. During this project, we will study the seasonal dynamics of marine protists, with special emphasis on toxic algae in the North Sea. Samples will be taken from four geographical distinct locations in the German Bight and from the Orkney Islands. Protist community composition will be assessed by Illumina sequencing and a newly developed fully automated biosensor system. The latter allows for automated sampling and filtration of water samples and automated detection of selected toxic algal species, while the detection is based upon electro chemical quantification of RNA by sandwich hybridization. Here we show first results of calibrating the biosensor for selected toxic algae that are known to occur in the North Sea. Furthermore, we also show preliminary results of the characterization of protist communities from spring to autumn 2016 at four different observation locations in the North Sea via Illumina sequencing.

Description: Information on recent biomass distribution and biogeography of photosynthetic marine protists with adequate temporal and spatial resolution is urgently needed to better understand consequences of environmental change for marine ecosystems. Here we introduce and review a molecular-based observation strategy for high resolution assessment of these protists in space and time. It is the result of extensive technology developments, adaptations and evaluations which are documented in a number of different publications and the results of recently accomplished field testing, which are introduced in this review. The observation strategy is organized at four different levels. At level 1, samples are collected at high spatio-temporal resolution using the remote-controlled automated filtration system AUTOFIM. Resulting samples can either be preserved for later laboratory analyses, or directly subjected to molecular surveillance of key species aboard the ship via an automated biosensor system or quantitative polymerase chain reaction (level 2). Preserved samples are analyzed at the next observational levels in the laboratory (level 3 and 4). This involves at level 3 molecular fingerprinting methods for a quick and reliable overview of differences in protist community composition. Finally, selected samples can be used to generate a detailed analysis of taxonomic protist composition via the latest Next Generation Sequencing Technology (NGS) at level 4. An overall integrated dataset of the results based on the different analyses provides comprehensive information on the diversity and biogeography of protists, including all related size classes. At the same time the cost effort of the observation is optimized in respect to analysis effort and time.

Description: Here we present a pilot study demonstrating, that preservation with mercury chloride allows the application of PCR-based molecular methods for the characterization of marine protist communities collected with moored long-term sediment traps. They can provide information on pelagic protist communities by collecting sinking plankton from the upper water column all year-round, even in remote polar oceans. Assessment of small protist species from the nano- and picoplankton fractions in sedimented material by microscopy is extremely challenging or almost impossible. Hence, comprehensive studies of variability in protist community composition in moored long-term sediment traps are scarce. Considering that marine nano- and picoeukaryotes are ecologically very important, new approaches are urgently needed to investigate protists in the smallest size-fractions of moored long-term sediment trap samples. We applied the quick and cost-effective Terminal Restriction Length Polymorphism (T-RFLP) on a set of selected samples that were collected between 2000 and 2010 in September at a depth of ~300 m in the area of the “LTER (Long-Term Ecological Research) site HAUSGARTEN” in the eastern Fram Strait (Arctic). The results of these analyses suggest a change in the trapped protist community after 2002 in this area. A comparison of 18S sequences obtained via 454-pyrosequencing from samples collected in the water column and mercury chloride preserved sediment traps in 2009 and 2010 suggests, that sediment traps might reflect the pelagic eukaryotic microbial biodiversity qualitatively. Furthermore, we have indication that preservation with mercury chloride does not severely change the nucleotide composition of 18S rRNA genes in long-term sediment traps. Overall, we suggest that preservation with mercury chloride is a key to open the door for molecular genetic analyses of long-term sediment trap samples, and that PCR-based molecular methods have a strong potential to become an important tool for comprehensive taxonomic analyses of protist- and bacterial communities in moored long-term sediment traps.

Description: nformation on recent diversity and biogeography of Arctic marine protists with adequate temporal and spatial resolution is urgently needed to better understand consequences of environmental change for marine ecosystems. Here, we introduce a molecular-based observation strategy for high resolution assessment of marine protists in space and time, even in remote areas such as the Arctic Ocean. The observation strategy involves molecular analyses (e.g. Next Generation Sequencing (NGS) or quantitative PCR) of samples, collected with a set of complementary methods such as a newly developed automated under-way sampling device, CTD-casts and moored sediment traps. This integrated approach allows generating detailed information on marine protist community composition or abundance with adequate resolution. Currently, the observation strategy is organized at four major levels. At level 1, samples are collected at high spatial and temporal resolution based on under-way sampling with the remote-controlled automated filtration system AUTOFIM (developed in the COSYNA-project), and sampling at fixed stations based on CTD-casts and moored sediment traps. Resulting samples can either be preserved for later laboratory analyses, or directly subjected to molecular surveillance of key species aboard the ship, e.g. via quantitative polymerase chain reaction (level 2). Preserved samples are analyzed at the next observational levels in the laboratory (level 3 and 4). This involves at level 3 molecular fingerprinting methods for a quick and reliable overview of differences in protist community composition. Finally, selected samples can be used to generate a detailed analysis of taxonomic protist composition via the latest Next Generation Sequencing Technology (NGS) at level 4. An overall integrated dataset of all results provides comprehensive information on the diversity and biogeography of protists, including all related size classes. In the future, the observation strategy for Arctic marine protists will be part of the Molecular Microbial Observatory envisioned for the Arctic observatory FRAM (Frontiers in Arctic Monitoring).