ALBERT

Description: During two cruises wiht RV Sonne, SO234-2 from 8 to 19 July 2014 (Durban, South Africa to Port Louis, Mauritius) and SO235 from 23 July to 7 August 2014 (Port Louis, Mauritius to Malé, Maldives), within the SPACES (Science Partnerships for the Assessment of Complex Earth System Processes) and OASIS (Organic very short-lived Substances and their air sea exchange from the Indian Ocean to the Stratosphere) research projects, surface water samples were sampled from a continuous running pump in the hydrographic shaft of RV Sonne at a depth of 5 m. Deep water samples were taken from a Niskin-bottle rosette sampler. The samples were then analyzed for halogenated compounds using a purge and trap system onboard, which was attached to a gas chromatograph with an electron capture detector for surface water samples and a GC/MS Agilent 5975 for the deep water samples. An analytical reproducibility of 10% was determined from measuring duplicate water samples, detection limit was 0.2 pmol /L. Calibration was performed with several dilutions of a mixed-compound standard prepared in methanol.

Description: The eVolv2k database includes estimates of the magnitudes and approximate source latitudes of major volcanic stratospheric sulphur injection (VSSI) events from 500 BCE to 1900 CE. The VSSI estimates incorporate recent improvements to the ice core records in terms of synchronization and dating, refinements to the methods used to estimate VSSI from ice core records, and includes first estimates of the random uncertainties in VSSI values. Ice core-derived volcanic sulfate deposition composites for Antarctica (Sigl et al., 2014) and Greenland (Sigl et al., 2015, Zielinski et al., 1995) are scaled to volcanic stratospheric sulfur injection based on a method similar to that of Gao et al. (2007). More details to be published in a forthcoming article (Toohey and Sigl, in prep). Compared to version 1, this version (1) contains estimates of the random error in the VSSI estimates, (2) includes a clarification regarding the format of years in the BCE period by including both years BCE/CE and according to the ISO 8601 standard (which includes a year 0), and (3) includes some minor modifications to the VSSI values. In addition, a reconstruction of stratospheric aerosol optical depth (AOD) using the VSSI estimates and the EVA v1 volcanic forcing generator (Toohey et al., 2016) is provided. Complete optical properties (extinction, single scattering albedo, scattering asymmetry factor) as a function of height, latitude and time can be produced using the eVolv2k VSSI database and the EVA forcing generator. Gao, C., Oman, L., Robock, A. and Stenchikov, G. L.: Atmospheric volcanic loading derived from bipolar ice cores: Accounting for the spatial distribution of volcanic deposition, J. Geophys. Res., 112(D9), doi:10.1029/2006JD007461, 2007. Sigl, M., Winstrup, M., McConnell, J. R., Welten, K. C., Plunkett, G., Ludlow, F., Büntgen, U., Caffee, M., Chellman, N., Dahl-Jensen, D., Fischer, H., Kipfstuhl, S., Kostick, C., Maselli, O. J., Mekhaldi, F., Mulvaney, R., Muscheler, R., Pasteris, D. R., Pilcher, J. R., Salzer, M., Schüpbach, S., Steffensen, J. P., Vinther, B. M. and Woodruff, T. E.: Timing and climate forcing of volcanic eruptions for the past 2,500 years, Nature, 523, 543¿549, doi:10.1038/nature14565, 2015. Sigl, M., McConnell, J. R., Toohey, M., Curran, M., Das, S. B., Edwards, R., Isaksson, E., Kawamura, K., Kipfstuhl, S., Krüger, K., Layman, L., Maselli, O. J., Motizuki, Y., Motoyama, H., Pasteris, D. R. and Severi, M.: Insights from Antarctica on volcanic forcing during the Common Era, Nat. Clim. Chang., 4, 693-697, doi:10.1038/nclimate2293, 2014. Toohey, M. and Sigl, M.: Volcanic stratospheric sulphur injections and aerosol optical depth from 500 BCE to 1900 CE, in preparation. Toohey, M., Stevens, B., Schmidt, H. and Timmreck, C.: Easy Volcanic Aerosol (EVA v1.0): an idealized forcing generator for climate simulations, Geosci. Model Dev., 9(11), 4049–4070, doi:10.5194/GMD-9-4049-2016, 2016. Zielinski, G. A.: Stratospheric loading and optical depth estimates of explosive volcanism over the last 2100 years derived from the Greenland Ice Sheet Project 2 ice core, J. Geophys. Res., 100(D10), 20937–20955, doi:10.1029/95JD01751, 1995.

Description: Coral reefs are currently experiencing substantial ecological impoverishment as a result of anthropogenic stressors, and the majority of reefs are facing immediate risk. Increasing ocean surface temperatures induce frequent coral mass bleaching events-the breakdown of the nutritional photo-symbiosis with intracellular algae (genus: Symbiodinium). Here, we report that Stylophora pistillata from a highly diverse reef in the Gulf of Aqaba showed no signs of bleaching despite spending 1.5 months at 1-2°C above their long-term summer maximum (amounting to 11 degree heating weeks) and a seawater pH of 7.8. Instead, their symbiotic dinoflagellates exhibited improved photochemistry, higher pigmentation and a doubling in net oxygen production, leading to a 51% increase in primary productivity. Nanoscale secondary ion mass spectrometry imaging revealed subtle cellular-level shifts in carbon and nitrogen metabolism under elevated temperatures, but overall host and symbiont biomass proxies were not significantly affected. Now living well below their thermal threshold in the Gulf of Aqaba, these corals have been evolutionarily selected for heat tolerance during their migration through the warm Southern Red Sea after the last ice age. This may allow them to withstand future warming for a longer period of time, provided that successful environmental conservation measures are enacted across national boundaries in the region.