SILT U Projects
Isotope Forensics of Gulf of Mexico Deepwater Horizon Oil Spill
N. Atlantic Radiocarbon Records and Heat Transport
Records of age-corrected radiocarbon (14C)
from corals and sclerosponges (collected and
shared byresearchers at the Stable Isotope
Laboratory of the University of Miami) will
be used to constrain heat transport by the
Subtropical Cells (STC’s) of the tropical N.
Atlantic Ocean. Locations of the records in
the Bahamas (subsurface return flow) and the island of Principe (equatorial upwelling zone) will be compared to records from the
Cape Verde Islands (frontal zone between upwelling and subducting water masses) to constrain positioning of the upwelling and subduction zones that comprise the STC’s. The data from this project will be important to paleoceanographers and oceanographic modelers alike as we seek more information about oceanic circulation variability.
Rivers large and small transport not only water, but sediment and affiliated carbon. Transport of the latter plays an important role in the part of the carbon cycle that is most affected by anthropogenic release of CO2. SILT U personnel are involved in analyzing sediment from the Mississippi River to determine the spectrum of ages (determined by measuring 14C content) present in organic
carbon affiliated withsuspended sediment and bed load
sediment during different flow regimes of the river. These
flow regimes include the 2008 high water event, one of 8
events in 80 years that necessitated flood control measures
above the city of New Orleans for protection of the city.
SILT U houses a novel programmed temperature pyrolysis/
combustion system (PTP/CS) that allows ramped pyrolysis radiocarbon dating.
Age Distributions of Organic Material Transported by the Mississippi River
The island of Lana’i, Hawai’i, has undergone profound changes since the arrival of Polynesians as well as the arrival of colonial settlers. Included in these changes is the formation of a prograding sediment deposit on the NE coast of the island that has buried sections of coral reef, changed drainage channels as they meet the ocean, and buried human structures. SILT U personnel are part of a larger group (Tulane Earth Surface Processes Group and LUMCON Wetlands and Subsidence Laboratory) that is studying the relationships between slope, sediment, and reef as it pertains to land use history.
Carbon and Sediment Cycling on the Island of Lana’i, Hawai’i
The SILT U group has recently sampled oil deposited along the coast of Grand Isle, Louisiana. Isotopic measurements will be made on oil from this environment, as well as other sampling sites along the vast Louisiana coastline, to “fingerprint” it. This initial work will be used to track it through the environment after assimilation into marsh and beach ecosystems.
