Marine sediments from the North Pacific document two episodes of expansion and strengthening of the subsurface oxygen minimum zone (OMZ) accompanied by seafloor hypoxia during the last deglacial transition. The mechanisms driving this hypoxia remain under debate. We present a new high-resolution alkenone palaeotemperature reconstruction from the Gulf of Alaska...
Non-intrusive track-based physical properties measurements of sediment cores recovered during ocean drilling are often biased by imperfect recovery within sediment core liners, particularly in heterogeneous and/or partially lithified sediments. These biases result in misrepresentation in measurements of true sediment physical properties, and can complicate integration of the composite site records...
An important constraint on mechanisms of past
carbon cycle variability is provided by the stable isotopic
composition of carbon in atmospheric carbon dioxide (δ¹³C-CO₂) trapped in polar ice cores, but obtaining very precise
measurements has proven to be a significant analytical challenge.
Here we describe a new technique to determine...
Analysis of observations and sensitivity experiments with a new three-dimensional global model of stable carbon isotope cycling elucidate processes that control the distribution of delta C-13 of dissolved inorganic carbon (DIC) in the contemporary and preindustrial ocean. Biological fractionation and the sinking of isotopically light delta C-13 organic matter from...
Oxygen isotope data from planktonic and benthic foraminifera, on a high-resolution age model (44 ¹⁴C dates spanning 17,400 years), document deglacial environmental change on the southeast Alaska margin (59°33.32′N, 144°9.21′W, 682 m water depth). Surface freshening (i.e., δ¹⁸O reduction of 0.8‰) began at 16,650 ± 170 cal years B.P. during...