Sea Ice Suppression of CO2 Outgassing in the West Antarctic Peninsula: Implications For The Evolving Southern Ocean Carbon Sink

The Southern Ocean plays an important role in the uptake of atmospheric CO2. In seasonally ice-covered regions, estimates of air-sea exchange remain uncertain in part because of a lack of observations outside the summer season. Here we present new estimates of air-sea CO2 flux in the West Antarctic Peninsula (WAP) from an autonomous mooring on the continental shelf. In summer, the WAP is a sink for atmospheric CO2 followed by a slow return to atmospheric equilibrium in autumn and winter. Outgassing is almost entirely suppressed by ice cover from June through October, resulting in a modest net annual CO2 sink. Model projections indicate sea ice formation will occur later in the season in the coming decades potentially weakening the net oceanic CO2 sink. Interannual variability in the WAP is significant, highlighting the importance of sustained observations of air-sea exchange in this rapidly changing region of the Southern Ocean

What is the fate of the river waters of Hudson Bay?

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 88 (2011): 352-361, doi:10.1016/j.jmarsys.2011.02.004.We examine the freshwater balance of Hudson and James bays, two shallow and fresh seas that annually receive 12% of the pan- Arctic river runoff. The analyses use the results from a 3–D sea ice-ocean coupled model with realistic forcing for tides, rivers, ocean boundaries, precipitation, and winds. The model simulations show that the annual freshwater balance is essentially between the river input and a large outflow toward the Labrador shelf. River waters are seasonally exchanged from the nearshore region to the interior of the basin, and the volumes exchanged are substantial (of the same order of magnitude as the annual river input). This lateral exchange is mostly caused by Ekman transport, and its magnitude and variability are controlled by the curl of the stress at the surface of the basin. The average transit time of the river waters is 3.0 years, meaning that the outflow is a complex mixture of the runoff from the three preceding years.We thank NSERC and the Canada Research Chairs program for funding. FS acknowledges support from NSF OCE-0751554 and ONR N00014-08-10490

A "critical" climatic evaluation of last interglacial (MIS 5e) records from the Norwegian Sea

Sediment cores from the Norwegian Sea were studied to evaluate interglacial climate conditions of the marine isotope stage 5e (MIS 5e). Using planktic forminiferal assemblages as the core method, a detailed picture of the evolution of surface water conditions was derived. According to our age model, a step-like deglaciation of the Saalian ice sheets is noted between ca. 135 and 124.5 Kya, but the deglaciation shows little response with regard to surface ocean warming. From then on, the rapidly increasing abundance of subpolar forminifers, concomitant with decreasing iceberg indicators, provides evidence for the development of interglacial conditions sensu stricto (5e-ss), a period that lasted for about 9 Ky. As interpreted from the foraminiferal records, and supported by the other proxies, this interval of 5e-ss was in two parts: showing an early warm phase, but with a fresher, i.e., lower salinity, water mass, and a subsequent cooling phase that lasted until ca. 118.5 Kya. After this time, the climatic optimum with the most intense advection of Atlantic surface water masses occurred until ca. 116 Kya. A rapid transition with two notable climatic perturbations is observed subsequently during the glacial inception. Overall, the peak warmth of the last interglacial period occurred relatively late after deglaciation, and at no time did it reach the high warmth level of the early Holocene. This finding must be considered when using the last interglacial situation as an analogue model for enhanced meridional transfer of ocean heat to the Arctic, with the prospect of a future warmer climate

Description of Amazonian Theobroma L. collections, species identification, and characterization of interspecific hybrids

There are two major in vivo collections of species of the genus Theobroma L. in Belém and Marituba, state of Pará, Brazil, and in both there are natural species, as well as natural and artificial interspecific hybrids. In order to organize a database of Brazilian Theobroma species, a description of the existing collections and detailed information about the interspecific hybrids, including an artificial key for their identification, are presented in this article