We analyzed 20 years (1993–2013) of observations of dissolved inorganic macronutrients (nitrate, N; phosphate, P; and silicate, Si) and chlorophyll a (Chl) at Palmer Station, Antarctica (64.8°S, 64.1°W) to elucidate how large-scale climate and local physical forcing affect the interannual variability in the seasonal phytoplankton bloom and associated drawdown of nutrients. The leading modes of nutrients (N, P, and Si empirical orthogonal functions 1, EOF1) represent overall negative anomalies throughout growing seasons, showing a mixed signal of variability in the initial levels and drawdown thereafter (low-frequency dynamics). The second most common seasonal patterns of nitrate and phosphate (N and P EOF2) capture prolonged drawdown events during December–March, which are correlated to Chl EOF1. Si EOF2 captures a drawdown event during November–December, which is correlated to Chl EOF2. These different drawdown patterns are shaped by different sets of physical and climate forcing mechanisms. N and P drawdown events during December–March are influenced by the winter and spring Southern Annular Mode (SAM) phase, where nutrient utilization is enhanced in a stabilized upper water column as a consequence of SAM-driven winter sea ice and spring wind dynamics. Si drawdown during November–December is influenced by early sea ice retreat, where ice breakup may induce abrupt water column stratification and a subsequent diatom bloom or release of diatom cells from within the sea ice. Our findings underscore that seasonal nutrient dynamics in the coastal WAP are coupled to large-scale climate forcing and related physics, understanding of which may enable improved projections of biogeochemical responses to climate change.
FacebookTwitterCopy LinkEmail Mari Hulman George Dies at 83NOVEMBER 3RD, 2018 MEGAN DIVENTI EVANSVILLE, INDIANAEvansville native and matriarch of Hulman & Company and the Indianapolis Motor Speedway has died. The IMS Chairman of the Board Emeritus passed away early Saturday morning at the age of 83.Mari Hulman George was born in December of 1934 in Evansville. When her father bought IMS in 1945, Hulman George was immersed into the world of auto racing.According to the Indianapolis Motor Speedway, Hulman George served as IMS Chairman from 1988 to 2016.Hulman George was well known to race fans as the individual who gave the command to start engines for the Indianapolis 500 and Brickyard 400 for more than 15 years.Family members say she touched the lives of many Hoosiers throughout her life.“She would treat everybody as if they were on the same level as she was,” says Daniel McCarthy, Mari Hulman George’s cousin. “You know she was not a pretentious person which was the beauty in that. That was a beautiful thing. I would say that that’s a legacy, but just the speedway everything that it stands for, you know that means a lot to Hoosiers and to be able to trace that back to Evansville.”The family says she will be buried in Terre Haute, Indiana.