ALBERT

Description: During the culmination of the phytoplankton spring bloom in the Fladen Ground area in April-Mai 1976, gross primary production was between 1500 and 2000 mg particulate C m**-2 day**-1, at a crop density (mainly diatoms of the genus Chaetoceros) of about 1500-3500 mg C m**-2. Estimates of the C:chlorophyll a ratio in living cells were much lower than those reported in the literature, possibly because part of what is measured as "chlorophyll a" by the common fluorometric method is associated with particles that are not reported as cells. Most of the dark 14C fixation during the bloom's climax was due to abiotic processes. Excretion of 14C-labeled carbohydrates did not account for a significant fraction of the total photosynthetic rate. The low crop after the bloom period, in June, corresponded with nutrient depletion of the euphotic zone. The low photosynthetic efficiency in June may have been a gross underestimate. The presence of relatively high concentrations of chlorophyll derivatives signifies that the algal crop was consumed by heterotrophs, but at a lower rate in April/May than during the June cruise when particularly high molar ratios of phaeophorbide a and phaeophytin a relative to chlorophyll a were found. The high respiratory rate relative to autotrophic production in June manifested itself also in high dark 14C fixation values. The high concentration of phaeophorbide a in the upper 40 m and its scarcity below this depth during the spring bloom climax in April/May implies that copepod grazing at that time took place principally in the euphotic zone. The remarkably high concentration of chlorophyllide a in the surface layer during the bloom period indicates that the part of the crop that was destroyed by the grazers while eating was occasionally as high as the part that was actually ingested.

Description: Here we present zircon petrochronological data, tephra whole-rock/glass compositions, and amphibole thermobarometry comprising the last four explosive eruptions of Ilopango Caldera in El Salvador (Tierra Blanca eruptive suite, TB). Our datasets include 238U-230Th disequilibrium geochronology, trace-elements, and oxygen isotope compositions from polished and unpolished zircon crystals analyzed using a CAMECA IMS 1280-HR secondary ion mass spectrometer (SIMS) at Heidelberg University, Germany. Additionally, pumice clasts whole-rock chemical analyses from the TB suite were performed at the German Research Centre for Geosciences (GFZ) using a PANalytical AXIOS Advanced wavelength-dispersive spectrometer, whereas major and trace-elements, glass shard, and mineral compositions were collected using an electron microprobe analysis (EMPA) at GEOMAR - Helmholtz-Centre for Ocean Research Kiel and by Laser Ablation Inductively Coupled Plasma - Mass Spectrometry (LA-ICP-MS) at Institute of Earth Sciences, Academia Sinica in Taipei. Whole-rock Sr-Nd isotope determinations were carried out at Departamento de Geología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE; Mexico) with a Nu-Instruments thermal ionization mass spectrometer (Nu-TIMS), whereas whole-rock U-series were determined using a ThermoFisher Neptune inductively-coupled mass-spectrometer multi-collector (ICP-MS-MC) at the University of Wyoming (UWYO, USA).

Description: This dataset includes results from oxygen isotope compositions from zircon crystal interiors (polished sections) of the Tierra Blanca Joven (TBJ) eruption from Ilopango caldera in El Salvador. Zircon crystals were analyzed employing Secondary Ion Mass Spectrometry at Heidelberg University.

Description: This dataset includes results from U-Pb dating from zircon crystal interiors (polished sections) of the Tierra Blanca Joven eruption (TBJ) from Ilopango caldera in El Salvador. Zircon crystals were analyzed employing Secondary Ion Mass Spectrometry at Heidelberg University.

Description: Bioassay data was collected using a bench top cage arena made of two Perspex cages (each 65 × 65 × 75 cm) connected through a rectangular Perspex tube of 65 cm at the top with 5 cm of both ends inserted into each cage. The tube had a square opening (entrance) of 5 × 5 cm fitted with a lid with both ends fitted with fine netting. The rectangular tube was demarcated into three zones; treatment, control and no choice. Fifty *Trioza erytreae* of same sex were introduced into the entrance and the number of insects were counted in each zone after one hour. Four replicates were done for each treatment set. The treatments were; Experiments 1; 1. Lemongrass vs air 2. Garlic vs air 3. Guava vs air Experiments 2; 4. Lemongrass vs rough lemon 5. Garlic vs rough lemon 6. Guava vs rough lemon Experiments 3; 7. Lemongrass+rough lemon vs rough lemon 8. Garlic+rough lemon vs rough lemon 9. Guava + rough lemon vs rough lemon. Insects counted in no zone were not included in the analysis.

Description: This dataset includes results from U-Th disequilibria dating from zircon rims (outermost crystal face) and crystal interiors (polished crystals) of the last four explosive silicic eruptions from Ilopango caldera in El Salvador (TBJ, TB2, TB3, and TB4). Zircon crystals were analyzed employing Secondary Ion Mass Spectrometry at Heidelberg University.

Description: This dataset includes results from trace element concentrations from zircon rims (outermost crystal face) and crystal interiors (polished sections) of the last four explosive silicic eruptions from Ilopango caldera (TBJ, TB2, TB3, and TB4) in El Salvador. Zircon crystals were analyzed employing Secondary Ion Mass Spectrometry at Heidelberg University.

Description: This dataset includes results from U-series and Sr-Nd whole-rock isotope compositions of the last four explosive silicic eruptions from Ilopango caldera in El Salvador (TBJ, TB2, TB3, and TB4). Sr and Nd isotope ratios were measured with a Nu Instruments thermal ionization mass spectrometer (Nu-TIMS) at Departamento de Geología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE) in the state of Baja California (Mexico), whereas U and Th concentrations and isotopes were measured at University of Wyoming (UWYO) were measured by isotope dilution using a ThermoFisher Neptune ICP-MS multicollector.

Description: This dataset includes results from amphibole geothermobarometry of explosive silicic eruptions from Ilopango caldera in El Salvador (TBJ, TB2, TB3, and TB4). Amphibole compositions were analyzed employing a JEOL JXA 8200 wavelength dispersive microprobe at the GEOMAR - Helmholtz-Centre for Ocean Research Kiel.