This dataset contains experimental data from a one-month aquarium-based bleaching experiment conducted on Large Benthic Foraminifera (Amphistegina lobifera) from 16 November to 16 December 2022 at the Marine Experimental Facility of the Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany. The aim of the experiment was to obtain symbiont-free A. lobifera individuals for future re-inoculation studies and symbiont switching experiments. The foraminifera were originally collected in May 2022 at the Interuniversity Institute for Marine Sciences (IUI) in Eilat, Israel (29°30'07.8N, 34°55'04.9E) and maintained in culture in Germany until the start of the experiment. To assess the effectiveness of two chemical agents—menthol and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU)—in disrupting symbiosis, photosynthetic efficiency (measured as maximum quantum yield, Fv/Fm) was recorded every other day during the first week of the experiment using a Pulse-Amplitude-Modulated (PAM) fluorometer. Fv/Fm measurements were discontinued after the first week due to complete inhibition of photosynthesis. Symbiont coverage (%) was assessed on day one and then weekly until week four using Confocal Laser Scanning Microscopy (CLSM).
LA-ICP-MS data from three different experiments including five foraminiferal species: Ammonia confertitesta (Bourgenuf, France), Bulimina marginata, Cassidulina laevigata (Gullmard Fjord, Sweden), Amphistegina lessonii and Operculina ammonoides (Eilat, Israel). Foraminifera were cultured at different oxygen concentrations (30% and 100% oxygen saturation). Element to calcium ratio (E/Ca) and partition coefficients (D) of Mg, Mn and Sr are noted for individual laser ablation measurements per specimen.
Culturing experiments were performed with the benthic foraminifer Ammonia aomoriensis from Flensburg Fjord, western Baltic Sea. The experiments simulated a projected rise in atmospheric CO2 concentrations. We exposed specimens to 5 seawater pCO2 levels ranging from 618 µatm (pH 7.9) to 3130 µatm (pH 7.2) for 6 wk. Growth rates and mortality differed significantly among pCO2 treatments. The highest increase of mean test diameter (19%) was observed at 618 µatm. At partial pressures >1829 µatm, the mean test diameter was observed to decrease, by up to 22% at 3130 µatm. At pCO2 levels of 618 and 751 µatm, A. aomoriensis tests were found intact after the experiment. The outer chambers of specimens incubated at 929 and 1829 µatm were severely damaged by corrosion. Visual inspection of specimens incubated at 3130 µatm revealed wall dissolution of all outer chambers, only their inner organic lining stayed intact. Our results demonstrate that pCO2 values of >=929 µatm in Baltic Sea waters cause reduced growth of A. aomoriensis and lead to shell dissolution. The bottom waters in Flensburg Fjord and adjacent areas regularly experience pCO2 levels in this range during summer and fall. Increasing atmospheric CO2 concentrations are likely to extend and intensify these periods of undersaturation. This may eventually slow down calcification in A. aomoriensis to the extent that net carbonate precipitation terminates. The possible disappearance of this species from the Baltic Sea and other areas prone to seasonal undersaturation would likely cause significant shifts in shallow-water benthic ecosystems in the near future.
About 30% of the anthropogenically released CO2 is taken up by the oceans; such uptake causes surface ocean pH to decrease and is commonly referred to as ocean acidification (OA). Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50 % of biogenic calcium carbonate in the open oceans. We have compiled the state of the art literature on OA effects on foraminifera, because the majority of OA research on this group was published within the last three years. Disparate responses of this important group of marine calcifiers to OA were reported, highlighting the importance of a process-based understanding of OA effects on foraminifera. We cultured the benthic foraminifer Ammonia sp. under a range of carbonate chemistry manipulation treatments to identify the parameter of the carbonate system causing the observed effects. This parameter identification is the first step towards a process-based understanding. We argue that CO3 is the parameter affecting foraminiferal size-normalized weights (SNWs) and growth rates. Based on the presented data, we can confirm the strong potential of Ammonia sp. foraminiferal SNW as a CO3 proxy.
The chemical and isotopic composition of foraminiferal shells (so-called proxies) reflects the physico-chemical properties of the seawater. In current day paleoclimate research, the reconstruction of past seawater carbonate system to infer atmospheric CO2 concentrations is one of the most pressing challenges and a variety of proxies have been investigated, such as foraminiferal U/Ca. Since in natural seawater and traditional CO2 perturbation experiments, the carbonate system parameters co-vary, it is not possible to determine the parameter of the carbonate system causing e.g. changes in U/Ca, complicating the use of the latter as a carbonate system proxy. We overcome this problem, by culturing the benthic foraminifer Ammonia sp. at a range of carbonate chemistry manipulation treatments. Shell U/Ca values were determined to test sensitivity of U incorporation to various parameters of the carbonate system. We argue that CO3 is the parameter affecting the U/Ca ratio and consequently, the partitioning coefficient for U in Ammonia sp DU. We can confirm the strong potential of foraminiferal U/Ca as a CO3 proxy.
Under stress, corals and foraminifera may eject algal symbionts ('bleach'), which can increase mortality. How bleaching relates to species viability over warming events is of great interest given current global warming. We use size-specific isotope analyses and abundance counts to examine photosymbiosis and population dynamics of planktonic foraminifera across the Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma), the most severe Cenozoic global warming event. We find that, unlike modern bleaching-induced mass mortality, populations of photosymbiont-bearing planktonic foraminifera increased in relative abundance during the PETM. Multigenerational adaptive responses including flexibility in photosymbiont associations and excursion taxa evolution may have allowed some photosymbiotic foraminifera to thrive. This dataset contains new records of size-specific stable isotope compositions and relative abundance changes in three clades of planktonic foraminifera from three ocean drilling sites (ODP Site 1209, DSDP Site 401, and ODP Site 690). We also include relevant published datasets used in the corresponding paper. Published high-resolution (~1-10 kyr) bulk isotope records provide a robust framework and inform us on the overall shape and timing of the Palaeocene-Eocene Thermal Maximum (PETM), whereas published multispecies planktic and benthic foraminifera provide a range of "expected" values for a given foraminifera size. We intentionally limited our compilation to high-resolution records that provide 1) a generic and/or specific-specific determination (i.e. we generally exclude "bulk" foraminifera isotope data, unless part of the original compilation), 2) a defined range of foraminiferal size, although often only defined by a soft limit i.e. "larger/smaller than X µm", 3) a continuous sampling resolution that resolves the shape of the PETM, in turn allowing for a data comparison across all sites and across all defined PETM time bins. All published datasets included in our compilation are well known in the palaeoceanography community. Many of these datasets have often been cited and reused in subsequent research, and persistent copy-errors are not uncommon. We used the original datasets and metadata given in the articles themselves. Original data and metadata is classically represented in tables or in the corresponding "Material and Methods" sections, published as supplementary information, or published in online databases such as Pangaea.de. We designed our compilation in a way that the data for all three sites (DSDP Site 401, ODP sites 690 and 1209) were presented in a uniform way, aiding internal comparisons and allowing further compilation work.
| Organisation | Count |
|---|---|
| Bund | 2 |
| Wissenschaft | 19 |
| Type | Count |
|---|---|
| Daten und Messstellen | 18 |
| Förderprogramm | 2 |
| License | Count |
|---|---|
| Offen | 20 |
| Language | Count |
|---|---|
| Deutsch | 1 |
| Englisch | 19 |
| Resource type | Count |
|---|---|
| Archiv | 2 |
| Datei | 16 |
| Keine | 2 |
| Topic | Count |
|---|---|
| Boden | 8 |
| Lebewesen und Lebensräume | 11 |
| Luft | 6 |
| Mensch und Umwelt | 14 |
| Wasser | 8 |
| Weitere | 20 |