The data layers provided show current values for seawater temperature, pH, calcite and aragonite saturation (%), oxygen concentration, and particulate organic carbon (POC) flux to the seafloor at different depths (500, 1000, 2000, 3000, and 4000m) at the present day (1951-2000) and changes in these variables expected between 2041-2060 and 2081-2100 under different RCP scenarios. The data layers were generated following the methods described in Levin et al. (2020). In short, in 2019, we obtained the present day and future ocean projections for the different years which were compiled from all available data generated by Earth Systems Models as part of the Coupled Model Inter-comparison Project Phase 5 (CMIP5) to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Three Earth System Models, including GFDL‐ESM‐2G, IPSL‐CM5A‐MR, and MPI‐ESM‐MR were collected and multi-model averages of temperature, pH, O2 , export production at 100-m depth (epc100), carbonate ion concentration (co3), and carbonate ion concentration for seawater in equilibrium with aragonite (co3satarg) and calcite (co3satcalc) were calculated. The epc100 was converted to export POC flux at the seafloor using the Martin curve (Martin et al., 1987) following the equation: POC flux = export production*(depth/export depth)0.858. The export depth was set to 100 m, and the water depth using the ETOPO1 Global Relief Model (Amante and Eakins, 2008). Seafloor aragonite and calcite saturation were computed by dividing co3 by co3satarg and co3satcalc. All variableswere reported as the inter-annual mean projections between 1951-2000, 2041-2060, and 2081-2100. The data for calcite and aragonite saturation can be found in Morato et al. (2020).
The 234Th–238U disequilibrium technique has been widely used to estimate the amount of particulate organic carbon (POC) exported from surface ocean layers to the deep sea. This method is based on determining 234Th fluxes from vertical 234Th–238U profiles in the water column and converting them into POC fluxes using POC/234Th ratios measured in sinking particles at a given calculation depth.
We present here an extensive repository of POC fluxes, together with Th fluxes and POC/234Th ratios. Covering all the global ocean, classified in 13 regions, season and moment of the bloom and calculated at three different depths:
i) a fixed depth (100 m)
ii) the reference depth in the paper associated to the base of the euphotic zone
iii) the 234Th–238U equilibrium depth.
To ensure a compilation representative of the global ocean, the dataset were selected using the division areas proposed by the international network JETZON (Joint Exploration of the Twilight Zone Ocean Network); that agreed a division of the oceans in 13 regions based on their contrasted physics and biogeochemical characteristics. The stations from 234Th publications associated to each JETZON region were carefully selected according to their ability to represent regional environmental conditions. Furthermore, station selection was based on essential criteria such as data quality and accessibility, availability of time series, clear definition of export depth, measurements from established programs, e.g. GEOTRACES, and the presence of other additional relevant ancillary data.
The data in the compilation are thus organized by region and include geographic coordinates, season, selected export depth, and other key factors (such as a description of the flux evaluation depth or the export depth zone).
After 234Th–238U compilation, 234Th fluxes were calculated, when possible, at the three different depths, i), ii) and iii), under the assumption of steady-state conditions, following Le Moigne et al. 2013.
Using POC/234Th ratios, POC fluxes are estimated from Th fluxes and both fluxes were included in the repository.
POC/234Th ratios were chosen from pump samples, prioritizing particles larger than 53 μm when available. These ratios must be estimated at the flux calculation depth [i), ii) and iii)]. When they were not available at the calculation depth POC/234Th values were interpolated as described in the readme text file. The values of the ratios are included in the repository, specifying the depth at which they were determined and indicating whether they have been interpolated. Similarly, when 234Th, 238U concentrations were not available at the calculation depth, values were interpolated (see readme text file).
With its 260,000 catalogued specimens, the ichthyological collection of the LIB at the Hamburg site hosts the largest fish collection of Germany. The collection comprises specimens from more than 8,000 fish species representing about a quarter of all known fish species worldwide. The collection includes more than 3,100 type specimens from about 500 valid species. About 98% of the collection material is stored in 70% ethanol in glass jars or stainless steel tanks. The collection also contains some specimen fractions such as skin preparations, dried skeletons, skulls, jaws, scales and otoliths, as well as DNA samples, photographs, x-rays and related publications. The fish collection is world-wide in coverage and comprises marine, freshwater and diadromous species. Marine fishes are mainly represented by lots from the Atlantic Ocean and adjacent waters, especially from the North and Baltic Seas. The collection comprises also comprehensive material from the deep sea and coral reefs of the Pacific and Indian Oceans. The Myctophidae, a marine family of Actinopterygii, comprises more than 4,800 lots, the highest number of catalogued lots of a family in the collection. Elasmobranchii are mainly represented in the collection with the family Rajidae, comprising more than 1,400 lots. Extensive material of freshwater fishes stems from Europe, Asia and Africa as well as from South and Middle America. The majority of the holdings of the fish collection is digitalized.
The Annelida collection was established in November 2019 to unite the primarily marine “Polychaeta” collection and the primarily terrestrial and freshwater Oligochaeta and Hirudinea collection, which were historically divided between two Invertebrates collections at the Museum of Nature - Zoology Hamburg. Revisions to annelid classification over the past decade mean that the collection now also includes the former phyla Echiura and Sipuncula. The collection is globally significant and contain important type collections for Oligochaeta (earthworms) and Polychaeta (marine Annelida). Altogether, the collection contains approximately 170,000 specimens, which are mostly preserved in ethanol. The terrestrial and freshwater annelid collection contains approximately 1500 type specimen lots and more than 20% of the known global diversity of earthworm species are represented. The heart of this collection are the specimens collected in the late 19th and early 20th centuries by Johann Wilhelm Michaelsen. The marine annelid collection contains more than 2000 type specimen lots, making it among the most important type collections in the world. The types represent species described by Ernst Ehlers, Hermann Augener, and Gesa Hartmann-Schröder, among many others. The geographic focus of the collection on the deep sea, poles, and the southern hemisphere originates from the intensive sampling efforts in these areas by the previous curators Johann Wilhelm Michaelsen, Gesa Hartmann-Schröder and Angelika Brandt. The collection continues to grow through new field collections and donations from researchers around the world.
Coccolithophoriden sind eine Gruppe von ca. 200-300 marinen Phytoplanktonarten, die in allen Weltmeeren vorkommt. Sie besitzen die besondere Fähigkeit eine Kalkschale (Coccosphäre) zu bauen, die sie aus vielen kleinen Kalkplättchen (Coccolithen) zusammensetzen. Aufgrund ihrer Fähigkeit zu kalzifizieren sind sie ein wichtiger Bestandteil im Klimasystem, denn die Produktion von Kalk nahe der Meeresoberfläche führt zu einem vertikalen Gradienten der Seewasseralkalinität, beschleunigt den Kohlenstoffexport in die Tiefsee und erhöht die Rückstrahlung von einfallender Sonnenenergie von der Erdoberfläche ins Weltall. Trotz intensiver Forschung an der Physiologie der Kalzifizierung und dessen biogeochemischer Relevanz konnten wir eine der entscheidenden Fragen immer noch nicht beantworten: Wozu bauen Coccolithophoriden eine Kalkschale? Die Beantwortung dieser Frage ist von außerordentlicher Bedeutung, denn solange wir nicht wissen wozu die Kalkschale dient können wir auch nicht vorraussagen in welchem Maße sich die durch die Ozeanversauerung zu erwartende Abnhame in der Kalzifizierung negativ auf die Fitness dieser Lebewesen in ihrem natürlichen Lebensraum auswirkt. In dem hier vorgestellten Projekt möchten wir die Frage nach der Bedeutung der Kalzifizierung erforschen, indem wir untersuchen ob die Coccosphäre einen Schutz gegen planktonische Räuber, Bakterien und Viren darstellt. Dazu haben wir eigens einen experimentellen Ansatz entwickelt wobei kalzifizierte und dekalzifizierte Coccolithophoridentzellen zusammen mit deren Fressfeinden und Pathogenen kultiviert werden. Dieser Ansatz erlaubt es uns folgende Fragestellungen zu untersuchen: 1) Sind kalzifizierte Zellen besser in der Lage sich gegen Fraß und Infektion zu schützen als Zellen ohne Coccosphäre? 2) Bevorzugen Fressfeinde und Pathogene solche Zellen, bei denen die Coccosphäre entfernt wurde, wenn ihnen beides angeboten wird? 3) Sind Wachstum und Reproduktion von Fressfeinden und Pathogenen verlangsamt, wenn sie kalzifizierte Zellen fressen oder infizieren?