Group items tagged

"Recognising ocean acidification in deep time: An evaluation of the evidence for acidification across the Triassic-Jurassic boundary Sarah E. GreeneCorresponding author contact information, 1, E-mail the corresponding author, Rowan C. Martindale1, E-mail the corresponding author, Kathleen A. Ritterbush E-mail the corresponding author, David J. Bottjer E-mail the corresponding author, Frank A. Corsetti E-mail the corresponding author, William M. Berelson E-mail the corresponding author Department of Earth Sciences, University of Southern California, Los Angeles, California, USA 90089 Received 22 July 2011. Accepted 17 March 2012. Available online 5 April 2012. While demonstrating ocean acidification in the modern is relatively straightforward (measure increase in atmospheric CO2 and corresponding ocean chemistry change), identifying palaeo-ocean acidification is problematic. The crux of this problem is that the rock record is a constructive archive while ocean acidification is essentially a destructive (and/or inhibitory) phenomenon. This is exacerbated in deep time without the benefit of a deep ocean record. Here, we discuss the feasibility of, and potential criteria for, identifying an acidification event in deep time. Furthermore, we investigate the evidence for ocean acidification during the Triassic-Jurassic (T-J) boundary interval, an excellent test case because 1) it occurs in deep time, beyond the reach of deep sea drilling coverage; 2) a potential trigger for acidification is known; and 3) it is associated with one of the 'Big Five' mass extinctions which disproportionately affected modern-style invertebrates. Three main criteria suggest that acidification may have occurred across the T-J transition. 1) The eruption of the Central Atlantic Magmatic Province (CAMP) and the associated massive and rapid release of CO2 coincident with the end-Triassic mass extinction provide a suitable trigger for an acidification event (

"Abstract The Phanerozoic fossil record of marine animal diversity covaries with the amount of marine sedimentary rock. The extent to which this covariation reflects a geologically controlled sampling bias remains unknown. We show that Phanerozoic records of seawater chemistry and continental flooding contain information on the diversity of marine animals that is independent of sedimentary rock quantity and sampling. Interrelationships among variables suggest long-term interactions among continental flooding, sulfur and carbon cycling, and macroevolution. Thus, mutual responses to interacting Earth systems, not sampling biases, explain much of the observed covariation between Phanerozoic patterns of sedimentation and fossil biodiversity. Linkages between biodiversity and environmental records likely reflect complex biotic responses to changing ocean redox conditions and long-term sea-level fluctuations driven by plate tectonics. "

"Oil Exploration Oil Exploration Gulf Drilling Disaster Triggers Scrutiny of Mediterranean Oil Rush 1. Laura Margottini* A rush to find and extract oil in the Mediterranean Sea is threatening one of the planet's marine biodiversity hot spots, scientists warn. PANTELLERIA, ITALY-This tiny speck in the Mediterranean, home to a few thousand people, seems like one of the most tranquil places in the world. But looks are deceptive. Pantelleria, in the Strait of Sicily halfway between Palermo and Tunis, is close to one of the world's busiest shipping lanes, and of late, its waters have also become the center of a new oil rush. Attracted by Italy's easygoing drilling regulations and low tax on oil extraction, dozens of companies have new plans for exploration and drilling in this part of the Mediterranean Sea. At a recent meeting here,* however, scientists, conservationists, and environmental activists warned that such efforts put several important biodiversity hot spots in danger. An oil disaster like the Deepwater Horizon explosion, which sent oil gushing into the Gulf of Mexico for months, could easily ruin the Mediterranean ecology for a century or longer, some said. The Italian government has recently issued 66 permissions for drilling around its coasts and 25 concessions for exploration. Another 67 applications for exploration are under review. "Italy now represents the region that holds the most exciting and significant long-term opportunities," one company, Northern Petroleum, says on its Web site. The Strait of Sicily is the center of attention, but other biodiversity hot spots, such as the Tremiti Islands in the Adriatic Sea, could soon be explored as well. Italy isn't alone. Tunisia, for example, has granted concessions for oil exploration for most of its Mediterranean waters, without much political opposition. But the areas coveted by oil companies are ecological treasures, researchers and groups such as Greenpeace Italy stress. Last year, the Uni

So, might you ask, what is the Anthropocene? First, the etymology. The Ancient Greek [anthropos] means "human being" while [kainos] means "new, current." The Anthropocene would thus be best defined as the new human-dominated period of the Earth's history. The term was proposed in 2000 by Paul J. Crutzen, Nobel Prize in 1995 for his work on atmospheric chemistry and his research on stratospheric ozone depletion (the so-called "hole"), and by Eugene F. Stoermer in a publication (p. 17) of the International Geosphere-Biosphere Programme. But the concept itself, the idea that human activity affects the Earth to the point where it can cross a new age, is not new and dates back to the late nineteenth century. Different terms were proposed over the decades, such as Anthropozoic (Stoppani, 1873), Noosphere (de Chardin, 1922; Vernadsky, 1936), Eremozoic (Wilson, 1992), and Anthrocene (Revkin, 1992). It seems that the success of the term chosen by Crutzen and Stoermer is due to the luck of having been made at the appropriate time, when humankind became more than ever aware of the extent of its impact on global environment. It should be noted that Edward O. Wilson (who suggested Eremozoic, "the age of loneliness") popularized the terms "biodiversity" and "biophilia." Technically, the Anthropocene is the most recent period of the Quaternary, succeding to the Holocene. The Quaternary is a period of the Earth's history characterized by numerous and cyclical glaciations, starting 2,588,000 years ago (2.588 Ma). The Quaternary is divided into three epochs: the Pleistocene, the Holocene, and now the Anthropocene.