The heartbeat of the Oligocene climate system

A 13-million-year continuous record of Oligocene climate from the equatorial Pacific reveals a pronounced “heartbeat” in the global carbon cycle and periodicity of glaciations. This heartbeat consists of 405,000-, 127,000-, and 96,000-year eccentricity cycles and 1.2-million-year obliquity cycles in periodically recurring glacial and carbon cycle events. That climate system response to intricate orbital variations suggests a fundamental interaction of the carbon cycle, solar forcing, and glacial events. Box modeling shows that the interaction of the carbon cycle and solar forcing modulates deep ocean acidity as well as the production and burial of global biomass. The pronounced 405,000-year eccentricity cycle is amplified by the long residence time of carbon in the oceans

Histopathological changes in gills and liver of Clarias gariepinus fingerlings exposed to acute concentrations of dry cell battery

Waste dry cell batteries are frequently improperly disposed and subsequently washed into water bodies-- causing deleterious effects on fish particularly Clarias gariepinus which inhabits diverse freshwater habitats. Acute toxicity of water-soluble fractions of waste dry cell batteries was investigated on C. gariepinus fingerlings under laboratory conditions in 96 hours. Ten (10) C. gariepinus fingerlings were exposed to acute concentrations (0.31, 0.63, 1.25, 2.50, and 5.00 g/L) of waste dry cell batteries and a control (0.00 g/L), each duplicate replicated. Histopathological alterations  evident in the gills were lamellar fusion, hyperplasia, inter-lamella space occlusion, hypertrophy and erosion of secondary lamellae. The liver showed nuclear and hepatocytes degeneration, vacuolation and portal congestion. Acute concentrations of water-soluble fractions of waste dry cell batteries caused significant (P<0.05) changes in the histomorphology of the gills and liver of C. gariepinus fingerlings, therefore indiscriminate disposal of waste dry cell batteries around riparian ecosystem should be safeguarded to reduce the declining diversity and abundance of freshwater fish species. Keywords: African catfish, 96 hr.LC50, Fingerlings, Histopathology Zinc-carbon batter

Pacific Oligocene reference curve (invited talk)

We present an uninterrupted chronology of climate and ocean carbon chemistry from ODP Site 1218 recovered in the equatorial Pacific, from the Eocene/Oligocene to the Oligocene/Miocene boundary, ~34 to 23 Ma. Using astronomically age calibrated data we find a strong imprint of the 405, 127 and 96-thousand-year (kyr) Earth's eccentricity as well as a dominant influence of the 1.2 million year (Myr) obliquity amplitude modulation cycles on periodically re-occurring Oligocene glacial and carbon cycle events. In combination, these astronomical modulations act as the "heartbeat" of the Oligocene climate system. The response of the climate system to intricate orbital variations is striking and suggests a fundamental role of the carbon cycle in the interaction between solar forcing and climate. Our record provides a new high-resolution view of the Oligocene climate system, prompts a re-evaluation of the previously hypothesised late Oligocene deglaciation, and sheds new light on Oligocene inter-ocean basin gradients between the Atlantic, Southern Ocean, and Pacific. Salient observations include foraminiferal benthic stable oxygen and carbon isotopes that co-vary, a phase lag of d13C w.r.t. d18O for the 405 kyr cycle, preferential filtering of longer orbital periods in d13C, presumably due to TCO2 reservoir buffering. We then use simple orbitally forced carbon cycle box models and manage to re-create the patterns observed in our data, including the overall strong amplitude of 405 kyr cycles in d13C. These models show a strong amplification of the lower astronomical frequencies, as observed in our data

UVMag:stellar formation, evolution, structure and environment with space UV and visible spectropolarimetry

Important insights into the formation, structure, evolution and environment of all types of stars can be obtained through the measurement of their winds and possible magnetospheres. However, this has hardly been done up to now mainly because of the lack of UV instrumentation available for long periods of time. To reach this aim, we have designed UVMag, an M-size space mission equipped with a high-resolution spectropolarimeter working in the UV and visible spectral range. The UV domain is crucial in stellar physics as it is very rich in atomic and molecular lines and contains most of the flux of hot stars. Moreover, covering the UV and visible spectral domains at the same time will allow us to study the star and its environment simultaneously. Adding polarimetric power to the spectrograph will multiply tenfold the capabilities of extracting information on stellar magnetospheres, winds, disks, and magnetic fields. Examples of science objectives that can be reached with UVMag are presented for pre-main sequence, main sequence and evolved stars. They will cast new light onto stellar physics by addressing many exciting and important questions. UVMag is currently undergoing a Research & Technology study and will be proposed at the forthcoming ESA call for M-size missions. This spectropolarimeter could also be installed on a large UV and visible observatory (e.g. NASA’s LUVOIR project) within a suite of instruments