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Diversität und Embryologie des 'lebenden Fossils' Spirula

Die Arbeitsgruppe von Prof. Dr. Keupp im Institut für Paläontologie der Freien Universität Berlin beschäftigt sich seit mehreren Jahren erfolgreich mit der Paläobiologie von Ammonoideen und anderen Cephalopoden. Spirula, ein 'lebendes Fossil', ist die einzige rezente Coleoiden-Gattung mit spiralig eingerolltem, vom Weichkörper umhüllten Gehäuse. Der Protoconch (frühontogenetische Schale), das Proseptum und das Ende des Siphonalrohres von Spirula ähneln, anders als bei Sepia und Nautilus, sehr dem der Ammonoidea. Spirula kann somit Modellcharakter für die Embryonalentwicklung insbesondere der Schalen- und Siphonalentwicklung von Ammonoideen haben. Das vorgelegte Forschungsvorhaben soll klären, ob es sich bei Spirula um eine oder mehrere Arten handelt. Die Notwendigkeit der Beantwortung der Frage nach der phylogenetischen Einordnung von Spirula drängt sich aufgrund widersprüchlicher Daten auf. Beide Fragestellungen werden anhand molekularer Daten (DNA-Sequenzen) analysiert. Die Embryologie von Spirula, über die bislang nur Vermutungen angestellt wurden, soll detailliert untersucht werden.

Compilation of major and trace element concentrations in mesopelagic and other species from the North Atlantic and the Mediterranean Sea

Organisms accumulate major and trace elements (including metals) directly from the external environment and/or indirectly through diet. As such, their elemental composition can help to infer dietary preferences, solve trophic links and/or inform quantitative dietary analysis primarily based on carbon and nitrogen stable isotopes or on fatty acids (Lahaye et al. 2005, Ramos and González-Solís 2012, Soto et al. 2016, Majdi et al. 2018). This dataset reports the total concentrations of 30 major and trace elements analysed in whole bodies or in the muscle tissue of 82 unique species or genera characteristic of meso- to bathypelagic waters (referred as “mesopelagic”) or living on the continental shelf (referred as “other”). The species encompass jellyfish, crustaceans, cephalopods, fish, and were collected in North Atlantic and Mediterranean areas between 1968 and 2018. When available, the sampling method/gear as well as the sampling depth are specified. For the element mercury (Hg), the concentration of organic forms (referred as methyl-Hg) is also given when available, as well the percentage of these organic forms (% methyl-Hg) relative to total Hg. A column specifies whether concentrations are expressed on a dry weight or wet weight basis (weight of the animal tissue after being dried or containing water, respectively). All element concentrations given on a wet weight basis can be converted on a dry weight basis (and vice-versa if necessary) according to the percentages of moisture given for each sample analysed (when available). Data were compiled from 27 published studies/papers for which DOI are indicated, for further details and information on the samples analysed and/or the analytical techniques used.

Forschergruppe (FOR) 2332: Temperature-related stresses as a unifying principle in ancient extinctions (TERSANE), Teilprojekt: Größenveränderungen von Cephalopoden während der Pliensbachium-Toarcium Krise

Die Reduzierung der Körpergröße innerhalb von Taxa wird als eine der wichtigsten Antworten in Hinblick auf klimaabhängigen Stressfaktoren gesehen. Trotz der üblichen Deutungen bei ähnlichen Größenveränderungen im Umfeld verschiedener Massenaussterbeereignisse werden ihre globale Bedeutung ebenso wie ihre damit verbunden Mechanismen diese Lilliput-Effekts nach wie vor kontrovers diskutiert. Das Projekt hat zum Ziel, die Rolle der Erwärmung und damit verbundener Stressfaktoren (Anoxia) in Hinblick auf Größenänderungen von marinen Organismen während der unterjurassischen Faunenkrise im Toarcium zu verstehen. Wir betrachten Cephalopoden aus W-Europa und NW-Afrika entlang eines N/S-Gradienten, um Größenverteilungsmuster von einzelnen Taxa bis zu Vergesellschaftungen zu untersuchen. Die erhaltenen Muster werden in Hinblick auf Fazies, physiko-chemische Proxies und physiologische Vorhersagen gründlich analysiert, um die Korrelation von Körpergröße und Umweltparametern, wie Temperatur, Sauerstoffverfügbarkeit und Produktion/Einlagerung von organischem Kohlenstoff zu testen.

Bulk stable isotope analysis (SIA) of historical and contemporary squid beaks

Raw data obtained from stable isotope analysis of δ13C and δ15N in beaks of the squids Gonatus fabricii (Lichtenstein, 1818) and Todarodes sagittatus (Lamarck, 1798) (Cephalopoda: Oegopsida), and primary analyses of these data. Squids sampled in the Baffin Bay, Davis Strait and Nordic Seas (1882-2010) and Iceland, Faroe Islands and Ireland (1844-2023), respectively. The beaks either come from the squids caught as bycatch, or from natural history museums, from stomach contents of predators.

Compilation of energy density of marine biota from the Northeast Atlantic and the Mediterranean Sea

Information on the energy density of prey is critical for estimating food requirements and consumption by predators and modelling energy flux through food webs (Van de Putte et al., 2006). We compiled energy density values for 121 marine species or genera from 12 published sources. The dataset encompasses 71 benthic and pelagic fish, 29 crustaceans, 15 cephalopods, 2 elasmobranchs, 2 jelly fish and 1 salp, sampled in the central and Northeast Atlantic and in the Mediterranean Sea between 1992 and 2017. Data were collected from studies that measured energy density directly by bomb calorimetry, and those studies that measured the proximate composition (i.e. the percentage of proteins, lipids and carbohydrates) of sampled tissues and converted these percentages into energy using combustion equivalents reported in the literature. When available, we reported energy density (or mean density, for samples with more than one individual) as a function of dry and wet weight, and the moisture percentage of samples. For each data record, we also provided the sampling location, geographic coordinates, month and year of sample collection, method of sample collection, taxonomic ranks (phylum, class, order, family), number and size (or size range) of sampled organisms, as well as the reference and DOI of the original data source, for further details on the samples analysed and/or the analytical techniques used.

Compilation of stable nitrogen and carbon isotope ratios of marine biota from the central and Northeast Atlantic, and the Mediterranean Sea

Bulk stable isotope ratios, primarily of carbon (δ13C) and nitrogen (δ15N), are increasingly used to examine predator-prey interactions and food web structure. We compiled δ13C and δ15N values of marine taxa from 56 published sources to support investigations on trophic interactions in mesopelagic food webs and assess the importance of mesopelagic organisms in the marine ecosystem. A total of 2095 records were collected, representing 8716 individual organisms from 349 unique species or genera sampled across the central and Northeast Atlantic, and the Mediterranean Sea, between 1905 and 2020. Records include 185 benthic and pelagic fish, 47 cephalopods, 31 marine mammals, 30 crustaceans, 26 elasmobranchs, 16 seabirds, 4 marine turtles, 4 jelly fish, 3 copepods, 2 salps, in addition to data from several organisms only identified to higher taxonomic ranks (family or above). The dataset includes isotopic ratios measured in the tissues or in the whole body of individual organisms, or mean values (and standard deviations) from pooled samples. Because lipids have more negative δ13C values relative to other major biochemical compounds in plant and animal tissues (DeNiro & Epstein, 1977), many studies correct for the lipid effect by extracting lipids from samples before analysis, or a posteriori, through mathematical corrections (Post, 2002). Therefore, δ13C values were reported as uncorrected, lipid-extracted, or mathematically-corrected. When available, the total organic carbon to nitrogen ratio (C:N) was included. For each data record, we also provided the sampling location, geographic coordinates, month and year of sample collection, method of sample collection, taxonomic ranks (phylum, class, order, family), number and size (or size range) of sampled organisms, as well as the reference and DOI of the original data source, for further details on the samples analysed and/or the analytical techniques used.

Compilation of trophic positions of marine biota from the central and Northeast Atlantic, and the Mediterranean Sea

Fractional trophic levels (i.e., trophic positions) describe the position of organisms within food webs and help define their functional roles in ecosystems (Odum & Heald, 1975). Trophic positions are thus critical for characterizing species' diets and energy pathways, investigating food web dynamics and ecosystem functioning, and assessing ecosystem health and resilience (Pauly et al., 1998; Pauly & Watson, 2005; Vander Zanden & Fetzer, 2007). We compiled estimates of trophic positions of marine organisms sampled across North Atlantic and Mediterranean waters between 1974 and 2015, gathered from 33 published and unpublished sources. The dataset comprises 208 unique species or genera, including zooplankton, decapods, cephalopods, pelagic and benthic fish, elasmobranchs, marine mammals, marine turtles, seabirds, as well as detritus. Estimates of trophic position were based on the analyses of stomach contents, bulk nitrogen stable isotopes (δ15N values), or amino acid compound-specific nitrogen isotopic analysis. For each data record, we also provided the sampling location, geographic coordinates, month and year of sample collection, method of sample collection, taxonomic ranks (phylum, class, order, family), number and size (or size range) of sampled organisms, type of analyses and estimation method, as well as the reference and DOI of the original data source, for further details on the samples analysed and/or the analytical techniques used.

Compilation of fatty acid composition of marine biota from the central and Northeast Atlantic, and the Mediterranean Sea

Fatty acid (FA) composition has increasingly been used to estimate the dietary preference of marine organisms. Specific fatty acids and fatty acid ratios serve as trophic markers (FATM) and have the potential to provide insights on the long-term dietary preference of organisms. FATM have been applied for this purpose on various zooplankton, fish and up to whales. We aim to build up a database of new and published data on fatty acid content of mesopelagic fish and their predators from the central and Northeast Atlantic, and the Mediterranean Sea, to use in FATM food web studies, investigating the importance of mesopelagic organisms as predators and prey in the marine ecosystem. Here we compiled FA content (i.e., the proportion of each FA measured in sampled tissues or in the whole body of organisms in relation to total FAs analysed) of 36 fish species or genera, 15 seabirds, five marine mammals, two cephalopods, one turtle, one jelly fish, and one shark. For each record, we included all FAs with values above 0.1% of total FAs and report the percentage values as provided in the original data source. Each data record is associated with information on the sampling location, geographic coordinates, month and year of sample collection, method of sample collection, taxonomic ranks (phylum, class, order, family), number and size (or size range) of sampled organisms, as well as the reference and DOI of the original data source, for further details on the samples analysed and/or the analytical techniques used.

Hochauflösende Ammoniten-Biostratigraphie im Oberjura Süddeutschlands

Analyse des Partikelflusses im Meer und der kleinraeumigen Verteilungsmuster planktischer Lebensgemeinschaften unter besonderer Beruecksichtigung larvaler und juveniler Tintenfische

Auf der Meteor-Expedition Mindik (Reise 5, Abschnitt 3) wurde im Fruehjahr 1987 ein umfangreiches biologisches Probenmaterial im Arabischen Meer gesammelt. Es bietet neue Moeglichkeiten, den Partikelfluss in einem tropischen Hochseegebiet zu untersuchen und regionale Unterschiede in der vertikalen und horizontalen Struktur der Planktongemeinschaften in oekologisch relevanter kleinraeumiger Aufloesung zu erfassen. Durch Pigmentuntersuchungen mit Hilfe der HPLC-Technik soll der Lebensweg von Phytoplanktonalgen in der Nahrungskette bis zur Sedimentation aufgezeigt werden. In der vergleichenden kleinraeumigen Analyse der planktischen Lebensgemeinschaften sollen zum anderen die Jugendstadien der Tintenfische im Mittelpunkt der Betrachtung stehen. Fuer diese Organismengruppe, deren Bestaende ein bedeutendes fischereiliches Potential darstellen, koennen am vorliegenden Material grundlegende Kenntnisse zur Taxonomie, Biologie und oekologischen Stellung erarbeitet werden.

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