Silicon isotopes of sediment core GeoB2107-3

The supply of nutrients to the low-latitude thermocline is largely controlled by intermediate-depth waters formed at the surface in the high southern latitudes. Silicic acid is an essential macronutrient for diatoms, which are responsible for a significant portion of marine carbon export production. Changes in ocean circulation, such as those observed during the last deglaciation, would influence the nutrient composition of the thermocline and, therefore, the relative abundance of diatoms in the low latitudes. Here we present the first record of the silicic acid content of the Atlantic over the last glacial cycle. Our results show that at intermediate depths of the South Atlantic, the silicic acid concentration was the same at the Last Glacial Maximum (LGM) as it is today, overprinted by high silicic acid pulses that coincided with abrupt changes in ocean and atmospheric circulation during Heinrich Stadials and the Younger Dryas. We suggest these pulses were caused by changes in intermediate water formation resulting from shifts in the subpolar hydrological cycle, with fundamental implications for the nutrient supply to the Atlantic.

Solar radiation over and under sea ice during the POLARSTERN cruise ARK-XXVI/3 (TransArc) in summer 2011

Arctic sea ice has declined and become thinner and younger (more seasonal) during the last decade. One consequence of this is that the surface energy budget of the Arctic Ocean is changing. While the role of surface albedo has been studied intensively, it is still widely unknown how much light penetrates through sea ice into the upper ocean, affecting sea-ice mass balance, ecosystems, and geochemical processes. Here we present the first large-scale under-ice light measurements, operating spectral radiometers on a remotely operated vehicle (ROV) under Arctic sea ice in summer. This data set is used to produce an Arctic-wide map of light distribution under summer sea ice. Our results show that transmittance through first-year ice (FYI, 0.11) was almost three times larger than through multi-year ice (MYI, 0.04), and that this is mostly caused by the larger melt-pond coverage of FYI (42 vs. 23%). Also energy absorption was 50% larger in FYI than in MYI. Thus, a continuation of the observed sea-ice changes will increase the amount of light penetrating into the Arctic Ocean, enhancing sea-ice melt and affecting sea-ice and upper-ocean ecosystems.

Benthic foraminifera and phytodetritus species in sediments from DSDP Leg 85, and ODP Legs 113 and 143

From late middle Eocene through earliest Oligocene, high-latitude regions cooled, and by the end of the period, continental ice sheets existed in Antarctica. Diversity of planktonic microorganisms declined, and modern groups of terrestrial vertebrates originated. Coeval faunal changes in deep-sea benthic foraminifers have been related to cooling of deep waters and increased oxygenation. Cooling, however, occurred globally, whereas species richness declined at high latitudes and not in the tropics. The late Eocene and younger lower-diversity, high-latitude faunas typically contain common Epistominella exigua and Alabaminella weddellensis, opportunistic phytodetritus-exploiting species that indicate a seasonally fluctuating input of organic matter to the sea floor. We speculate that the species-richness gradient and increase in abundance of phytodetritus-exploiting species resulted largely from the onset of a more unpredictable and seasonally fluctuating food supply, especially at high latitudes.

Modern music and musicians.

Head and tail pieces.

Establecimiento de baños de Arechavaleta, temporada de 1863 : memoria formada por su Medico Director en cumplimiento de lo prevenido en el Reglamento vigente del ramo /

Incluye cuadros estadísticos.

El emperador Commodo : historia discursiua segun el texto Herodiano /

Mode of access: Internet.

Synopsis nosologiae methodicae : continens genera morborum praecipua definita, additis speciebus cum harum ex Sauvagesio synonymis /

Mode of access: Internet.

Sylua locorum communium omnibus diuini verbi concionatoribus ... : in qua tum veterum Ecclesiae Patrum, tum phisolophorum, oratorum, [et] poëtarum, egregia dicta, aureaeq[ue] sententiae ... leguntur : in tres classes digesta : adiecto duplici indice /

Mode of access: Internet.

The diplomatic protection of citizens abroad; or, The law of international claims,

Published in part as the author's thesis (Ph.D.) Columbia University, 1914.

Kitāb manāfiʻ al-aghdhiyah wa-dafʻ maḍārrihā [microform] /

Microfilm.

Realencyklopädie für protestantische theologie und kirche,

Vol. 23, 24: Ergänzungen und nachträge, 1913.

Un maitre de l'art. Blake le visionnaire.

Bound in printed paper wrappers; spine reinforced.