Aerosols over the Arabian Sea

This paper provides an overview of dust transport pathways and concentrations over the Arabian Sea during 1995. Results indicate that the transport and input of dust to the region is complex, being affected by both temporally and spatially important processes. Highest values of dust were found off the Omani coast and in the entrance to the Gulf of Oman. Dust levels were generally lower in summer than the other seasons, although still relatively high compared to other oceanic regions. The Findlater jet, rather than acting as a source of dust from Africa, appears to block the direct transport of dust to the open Arabian Sea from desert dust source regions in the Middle East and Iran/Pakistan. Dust transport aloft, above the jet, rather than at the surface, may be more important during summer. In an opposite pattern to dust, sea salt levels were exceedingly high during the summer monsoon, presumably due to the sustained strong surface winds. The high sea salt aerosols during the summer months may be impacting on the strong aerosol reflectance and absorbance signals over the Arabian Sea that are detected by satellite each year.

Heat flow values in the Sea of Okhotsk region

Tectonic structure and anomalous distributions of geophysical fields of the Sea of Okhotsk region are considered; the lack of reliable data on age of the lithosphere beneath basins of various origin in the Sea of Okhotsk is noted. Model calculations based on geological and geophysical data yielded 65 Ma (Cretaceous-Paleocene boundary) age for the Central Okhotsk rise underlain by the continental lithosphere. This estimate agrees with the age (the end of Cretaceous) derived from seismostratigraphic data. A comparative analysis of theoretical and measured heat flows in the Akademii Nauk Rise, underlain by the thinned continental crust, is performed. The analysis points to a higher (by 20%) value of the measured thermal background of the rise, which is consistent with high negative gradient of gravity anomalies in this area. Calculations yielded 36 Ma (Early Oligocene) age and lithosphere thickness of 50 km for the South Okhotsk depression, whose seafloor was formed by processes of back-arc spreading. The estimated age of the depression is supported by kinematic data on the region; the calculated thickness of the lithosphere coincides with the value estimated from data of magnetotelluric sounding here. This indicates that formation time (36 Ma) of the South Okhotsk depression was estimated correctly. Numerical modeling performed for determination of the basement age of rifting basins in the Sea of Okhotsk gave the following estimates: 18 Ma (Early Miocene) for the Deryugin Basin, 12 Ma (Middle Miocene) for the TINRO Basin, and 23 Ma (Late Oligocene) for the West Kamchatka Trough. These estimates agree with formation time (Oligocene-Quaternary) of the sedimentary cover in rifting basins of the Sea of Okhotsk derived from geological and geophysical data. Model temperature estimates are obtained for lithologic and stratigraphic boundaries of the sedimentary cover in the Deryugin and TINRO Basins and the West Kamchatka Trough; the temperature analysis indicates that the latter two structures are promising for oil and hydrocarbon gas generation; the West Kamchatka Trough possesses better reservoir properties compared to the TINRO and Deryugin Basins. The latter is promising for generation of hydrocarbon gas. Paleogeodynamic reconstructions of the Sea of Okhotsk region evolution are obtained for times of 90, 66, and 36 Ma on the base of kinematic, geomagnetic, structural, tectonic, geothermal, and other geological and geophysical data.

Documentation, profile descriptions and analytical results of loes profiles from Bavaria, southern Germany

This study investigates the landscape evolution and soil development in the loess area near Regensburg between approximately 6000-2000 yr BP (radiocarbon years), Eastern Bavaria. The focus is on the question how man and climate influenced landscape evolution and what their relative significance was. The theoretical background concerning the factors that controlled prehistoric soil erosion in Middle Europe is summarized with respect to rainfall intensity and distribution, pedogenesis, Pleistocene relief, and prehistoric farming. Colluvial deposits , flood loams, and soils were studied at ten different and representative sites that served as archives of their respective palaeoenvironments. Geomorphological, sedimentological, and pedological methods were applied. According to the findings presented here, there was a high asynchronity of landscape evolution in the investigation area, which was due to prehistoric land-use patterns. Prehistoric land use and settlement caused highly difIerenciated phases of morphodynamic activity and stability in time and space. These are documented at the single catenas ofeach site. In general, Pleistocene relief was substantially lowered. At the same time smaller landforms such as dells and minor asymmetric valleys filled up and strongly transformed. However, there were short phases at many sites, forming short lived linear erosion features ('Runsen'), resulting from exceptional rainfalls. These forms are results of single events without showing regional trends. Generally, the onset of the sedimentation of colluvial deposits took place much earlier (usually 3500 yr BP (radiocarbon) and younger) than the formation of flood loams. Thus, the deposition of flood loams in the Kleine Laaber river valley started mainly as a consequence of iron age farming only at around 2500 yr BP (radiocarbon). A cascade system explains the different ages of colluvial deposits and flood loams: as a result of prehistoric land use, dells and other minor Pleistocene landforms were filled with colluvial sediments. After the filling of these primary sediment traps , eroded material was transported into flood plains, thus forming flood loams. But at the moment we cannot quantify the extent ofprehistoric soil erosion in the investigation area. The three factors that controlled the prehistoric Iandscapc evolution in the Ioess area near Regensburg are as follows: 1. The transformation from a natural to a prehistoric cultural landscape was the most important factor: A landscape with stable relief was changed into a highly morphodynamic one with soil erosion as the dominant process of this change. 2. The sediment traps of the pre-anthropogenic relief determined where the material originated from soil erosion was deposited: either sedimentation took place on the slopes or the filled sediment traps of the slopes rendered flood loam formation possible. Climatic influence of any importance can only be documented as the result of land use in connection with singular and/or statistic events of heavy rainfalls. Without human impact, no significant change in the Holocene landscape would have been possible.

Zooplankton abundance for two shelf stations off Galicia (NW Spain) from 1994 to 2006

Zooplankton was sampled by project RADIALES at Vigo (E3VI) and A Coruña (E2CO) between 1994 and 2006. Samples were collected using 50-cm diameter Juday-Bogorov (A Coruña) or 40-cm diameter bongo plankton nets (Vigo) equipped with 200-µm mesh size. Tows were double oblique from surface to near bottom (90 and 70 m in Vigo and A Coruña, respectively). All samples were collected between 10:00 and 14:00 o'clock (local time). Samples were preserved in 2-4% sodium borate-buffered formaldehyde. For the purpose of this study, the original coastal time series were categorized in copepods representative of crustacean zooplankton) and gelatinous plankton (medusae and tunicates). Medusae included Hydrozoans and Scyphozoa, and tunicates included salps, pyrosomes, doliolids, and appendicularia. Plankton identification and counts were performed by Ana Miranda and M. Teresa Álvarez-Ossorio for samples from Vigo and A Coruña, respectively. Different trends were found for gelatinous plankton in the two coastal sites, characterized by increases in either medusae or tunicates. Multiyear periods of relative dominance of gelatinous vs. copepod plankton were evident. In general, copepod periods were observed in positive phases of the main modes of regional climatic variability. Conversely, gelatinous periods occurred during negative climatic phases. However, the low correlations between gelatinous plankton and either climatic, oceanographic, or fishery variables suggest that local factors play a major role in their proliferations.