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Elemental, biochemical, and fatty acid contents for the copepod Temora longicornis (and its diets) fed under laboratory conditions with different nutrient regimes

The two experiments for which data is presented in this record were conducted in the context of RMFS' PhD work. The objective of the experiments was to quantify and qualify the effects of diet quality, herein manipulated in terms of different species (the diatom Conticribra weissflogii and the dinoflagellate Oxyrrhis marina) grown under different nutrient regimes (nutrient replete and Nitrogen-depleted), on the fatty acid (FA) assimilation and turnover of the copepod Temora longicornis. Experiments used field-collected copepods; sampling for experiments I and II took place on May 17th and 30th, 2016, respectively, with a 500 µm mesh-size CalCOFI net which was towed horizontally for 15 minutes at 5 m depth off the German island of Helgoland (54o11'N, 07o54'E), in the southern North Sea. Samples were immediately taken to the laboratory, where intact and active adult females were sorted under an Olympus SZX16 stereoscopic microscope. A total of 1260 females were sorted for each date, 1080 for the feeding experiment and 180 for the determination of in situ elemental and biochemical compositions. This study was conducted concomitantly with that from Franco-Santos et al. (2018). The feeding experiment was initiated after sorting, and lasted for five days. Females were distributed between triplicate 3L plastic beakers (75 females L-1), which were fitted with a 300 µm meshed-bottom cylinder, and kept in a dark, temperature-controlled room (10 ± 0.3oC, a temperature similar to that recorded in the surface water during sampling). Batch cultures of C. weissflogii were started on a daily basis (prior to starting the experiment) for five consecutive days; a stock solution was diluted with fresh f/2 medium (with and without nitrate additions, modified from Guillard, 1975), which contained 13C-enriched sodium bicarbonate (NaH13CO3, 4 mg L-1), and was grown for five days before being used to feed copepods (details in Franco-Santos et al., 2018). The same protocol was followed to culture the cryptophycean Rhodomonas salina, but bicarbonate was added to a concentration of 12 mg L-1. The algae were then used to feed the cultures of O. marina and, thus, create its different nutrient treatments. The dinoflagellate batches were cultured with the same protocol as the diatoms, except that the stock solution was diluted on a daily basis with labelled food (i.e., R. salina) rather than once at the start of the culture with isotopically-enriched medium. Cryptophycean cell quantities given to dinoflagellates were adjusted so that the former was depleted from the cultures on day 5. Diatom and dinoflagellate diets were provided for copepods ad libitum (> 350 µg C L-1; 8 and 2 * 103 cells mL-1, respectively) on a daily basis for five days. Cell density in the cultures was determined with a BD Accuri C6 Flow Cytometer. Beakers were gently stirred three times a day in order to resuspend dietary cells. Immediately before feeding copepods, a partial (approx. 65%) water exchange was conducted, which removed most of the food from the previous day. Copepods were sampled on days 1 (in situ composition, t0h), 3 (t48h), and 6 (t120h) of the experiment. Females were pooled into 10 and 50 individuals per replicate for elemental (body carbon (C) and nitrogen (N) contents and molar C:N ratio) and biochemical (total FA content and profile, and FA-specific content and 13C isotopic signal) analyses. Sampled copepods were gently washed in distilled water, then placed into pre-weighed tin capsules (5x9 mm, IVA Analysentechnik) or pre-combusted lipid vials (for elemental and FA analyses, respectively). Cultures were sampled daily during the experiment (after food was provided to copepods) for determination of cell elemental (C and N contents and molar C:N ratio) and biochemical (total FA content and profile, and FA-specific content and 13C isotopic enrichment) compositions. Subsamples of 5.2 and 0.4 *106 cells (for diatoms and dinoflagellates, respectively) were filtered through pre-combusted (500oC for 24h) Whatman GF/F filters (0.7 µm pore size, 25 mm diameter). Tin capsules and filters with samples for elemental analysis were dried at 60oC for 48 h; filters were folded inside tin foil, and both capsules and foil were stored in a desiccator until analysis. Filters with samples for FA analyses were placed into pre-combusted lipid vials, and vails containing both copepods and filters were stored at -80oC until analyses. The dry mass (DM) and C and N contents of samples were obtained as per Franco Santos et al. (2018). Lipid extraction (modified after Folch et al., 1957) and subsequent fatty acid methyl ester (FAME) quantification were performed as described in Franco-Santos et al. (2019) (and references therein). Temora longicornis does not have significant energy reserves and exhibits triacylglycerols (TAGs) as its primary neutral lipids (Fraser et al., 1989; Peters et al., 2013). Lipid classes were not separated in this study, and it was assumed that FAMEs were composed of TAGs. The FA-specific 13C isotopic composition of FAMEs was measured according to Boissonnot et al. (2016). Lipid C assimilation and turnover were calculated according to the equations used by Boissonnot et al. (2016) and Franco-Santos et al. (2019). Lipid C assimilation efficiency (AE), the percentage of (isotopically-enriched) dietary content ingested by copepods that was assimilated into FAs, was also calculated for (a) TFA, (b) saturation-specific sums of FAs (saturated, monounsaturated, and polyunsaturated FAs), and (c) each individual FA that was both available from the diet and assimilated by copepods (> 1% TFA in copepods). All the equations necessary for these calculations are described in the data sets contained in this bundled publication.

Cell count time series of Azadinium spinosum, Azadinium poporum and Amphidoma languida at Cuxhaven, Helgoland, Sylt, Wilhelmshaven and Scapa Flow between 2015 and 2019

The data represent species counts (cells L-1) of the three AZA-producing dinoflagellate species Azadinium spinosum, Az. poporum and Amphidoma languida (all members of the taxonomic family Amphidomataceae) of water samples taken during in total six different field expeditions on several research vessels (RV Heincke, RV Uthörn, RV Polarstern) and on in total five stationary sampling stations (Scapa Flow/Scotland, Cuxhaven/Germany, Helgoland/Germany, Wilhelmshaven/Germany, Sylt/Germany) between 2015 and 2019. The water samples have been taken using Niskin bottles (on research vessels attached to a CTD). After DNA extraction, the species cell numbers have been calculated by quantitative PCR (qPCR) analysis using respective standard curves. These samples gained from different geographical areas in the eastern North Atlantic have been analyzed as part of the RIPAZA Project (funded by the German BMBF; in cooperation with the Third Institute of Oceanography, Xiamen/China) and the results are presented and discussed in the doctoral thesis of Stephan Wietkamp (Suppl.Tab.S6, Suppl.Tab.S7). Aim of the project and especially of this data set was to provide first reference data on the biogeography (geographical distribution and seasonality) of toxigenic Amphidomataceae in the eastern North Atlantic.

Cell counts of Azadinium spinosum, Azadinium poporum and Amphidoma languida during POLARSTERN cruise PS92, UTHÖRN cruise UTH16 and various HEINCKE cruises to the eastern North Atlantic between 2015 and 2019

The data represent species counts (cells L-1) of the three AZA-producing dinoflagellate species Azadinium spinosum, Az. poporum and Amphidoma languida (all members of the taxonomic family Amphidomataceae) of water samples taken during in total six different field expeditions on several research vessels (RV Heincke, RV Uthörn, RV Polarstern) and on in total five stationary sampling stations (Scapa Flow/Scotland, Cuxhaven/Germany, Helgoland/Germany, Wilhelmshaven/Germany, Sylt/Germany) between 2015 and 2019. The water samples have been taken using Niskin bottles (on research vessels attached to a CTD). After DNA extraction, the species cell numbers have been calculated by quantitative PCR (qPCR) analysis using respective standard curves. These samples gained from different geographical areas in the eastern North Atlantic have been analyzed as part of the RIPAZA Project (funded by the German BMBF; in cooperation with the Third Institute of Oceanography, Xiamen/China) and the results are presented and discussed in the doctoral thesis of Stephan Wietkamp (Suppl.Tab.S6, Suppl.Tab.S7). Aim of the project and especially of this data set was to provide first reference data on the biogeography (geographical distribution and seasonality) of toxigenic Amphidomataceae in the eastern North Atlantic.

Elemental and biochemical contents of the copepod Temora longicornis

Elemental and biochemical contents of the diets of the copepod Temora longicornis

Fatty acid contents of the diets of the copepod Temora longicornis

Fatty acid contents of the copepod Temora longicornis

Untersuchungen zum Einfluss von Schadstoffen auf die Biolumineszenz mariner Dinoflagellaten. Entwicklung eines Leuchtalgentests

Die Dinoflagellaten-Lumineszenz ist unter physiologischen und enzymatischen Aspekten gut untersucht, fuer das aktive Monitoring in der Oekotoxikologie wurde diese Reaktion aber bisher noch nicht eingesetzt. Das Vorhaben soll die Moeglichkeiten untersuchen, die komplexe und mit hoher Empfindlichkeit messbare Biolumineszenz intakter Dinoflagellaten als Indikator fuer akute Schadstoffwirkungen zu nutzen. Dazu muss die natuerliche Reaktionsnorm der Testorganismen eingehend untersucht und ein geeignetes Messsystem konstruiert werden. Zu erwarten sind grundlegende Erkenntnisse ueber die Beeinflussbarkeit der Lumineszenz. Daneben wird die Entwicklung eines routinefaehigen Toxizitaetstestes angestrebt.

Erfassung der kryptischen Diversität von Alexandrium Arten in Australischen Gewässern: Entwicklung und Anwendung von molekularen Methoden für Langzeit Monotoring

Vetreter der marinen Dinoflagellaten Gattung Alexandrium produzieren das sehr starke Neurogift Saxitoxin (STX). Durch den Verzehr von kontaminierten Muscheln haben sie Einfluss auf die menschliche Gesundheit als auch auf die Aquakultur-Industrie. Noch ist wenig bekannt über die Faktoren und die Prozesse die Blütenbildung von Alexandrium Arten und ihren Populationen in Australischen Gewässern beeinflussen. Die Schwierigkeit die Alexandrium Arten einwandfrei und direkt bei Monitoring Programmen zu unterscheiden und das Auftreten von giftigen als auch ungiftigen Arten in den gleichen Regionen macht deren Überwachung sehr kompliziert. Es ist nötig mit modernen molekularen Methoden die Alexandrium-Diversität zu analysieren und Methoden zu entwickeln, welche eine sichere Diskriminierung und Quantifizierung ermöglicht. So soll ein tiefes Verständnis der Diversität ihre Verteilungen und die Dynamic der Population erreicht werden. In diesem Projekt werden wir tiefen Sequenzierungen (NGS) und qPCR Assays einsetzen um: 1. Die bisher unentdeckte Biodiversität von Alexandrium Arten aufzuschlüsseln; 2. Die Alexandrium-Populationsdynamiken in den Küstenregionen zu studieren 3. Kooperationen mit den Muschelfarmen und Monitoring Beauftragten Molekulare Methoden wie qPCR und Pyrosequenzierungen für Langzeitstudien zu ermöglichen.

Schnecken treiben Photosynthese?

Ein 'tierisches' Beispiel für Quantensprünge in der Evolution findet man bei den Meeresnacktschnecken. Schnecken der Gattung Phyllodesmium fressen bestimmte Weichkorallen (Briareum) und nehmen dadurch einzellige Algen (Dinoflagellaten) auf, die vorher symbiotisch in der Weichkoralle gelebt haben. Die Dinoflagellaten werden von der Schnecke nicht verdaut, sondern betreiben auch in der Schnecke weiterhin Photosynthese und versorgen diese mit Photosynthese-Produkten. Wir sind an der Evolution dieses Symbiose-Systems aus Koralle-Schnecke-Dinoflagellat interessiert und versuchen mit molekularbiologischen Methoden herauszubekommen, ob die Verteilung der Symbionten in der Schnecke von bestimmten Umständen abhängt.

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