Although marine productivity is a key parameter in the global carbon cycle, reliable
estimation of productivity in ancient marine systems has proven difficult. In this study, we …

Recent data imply that for much of the Proterozoic Eon (2500 to 543 million years ago),
Earth's oceans were moderately oxic at the surface and sulfidic at depth. Under these …

The macronutrient phosphorus is thought to limit primary productivity in the oceans on
geological timescales. Although there has been a sustained effort to reconstruct the …

For the past 3.8 billion years, the geochemistry of the Earth's surface-its atmosphere, waters
and exposed crust-has been determined by the presence of biota. Photosynthetic organisms …

IT is unknown when life first appeared on Earth. The earliest known microfossils (˜ 3,500 Myr
before present) are structurally complex, and if it is assumed that the associated organisms …

Phosphorus (P) is an essential element to all life, being a structural and functional
component of all organisms. 1-4 P provides the phosphate-ester backbone of DNA and …

The cycling of phosphorus (P) in the ocean has long been viewed from a geological
perspective that tends to focus on balancing P sources (riverine and atmospheric) and sinks …

The Corg: P ratios of organic-rich facies (TOC> 1%) exhibit considerable variation through
the Phanerozoic, from< 10: 1 in the Permian Phosphoria Formation to> 1000: 1 in some …

For more than a decade I have taught a graduate-level course in marine sediment
geochemistry that covers many of the topics discussed in this book. The goal now is to …

The latest Permian mass extinction (LPME) coincided with major changes in the composition
of marine plankton communities, yet little is known about concurrent changes in primary …