(Table 2) 230Th, 230Th xs and 232Th concentrations in dissolved, particulate and total (dissolved+small particles) for all KEOPS stations, Marion Dufresne cruise MD145

In the context of the KErguelen Ocean and Plateau compared Study (KEOPS, 19 January-13 February 2005), particle dynamics were investigated using thorium isotope measurements over and off the Kerguelen plateau. Dissolved and particulate 230Th and 232Th samples were collected at nine stations. Dissolved excess 230Th concentrations (230Thxs) vary from 0.5 to 20.8 fg/kg and particulate 230Thxs concentrations from 0.1 to 10.0 fg/kg. Dissolved and particulate 232Th concentration ranges are 16.8-450.2 pg/kg and 3.8-502.8 pg/kg, respectively. The 230Thxs concentrations increase linearly with depth down to the bottom at most of the plateau stations and down to 1000 m at the off-plateau stations. This linear trend is observed down to the bottom (1550 m) at Kerfix, the open-ocean "upstream" station located west of the Kerguelen plateau. A simple reversible scavenging model applied to these data allowed the estimation of adsorption rate constant (k1~=0.2-0.8 per year), desorption rate constant (k-1~=1-8 per year) and partition coefficients (average K=0.16±0.07). Calculated particle settling velocities S deduced from this simple model are ca. 500 m/year at most of the plateau stations and 800 m/year at all the off-plateau stations. The plateau settling velocities are relatively low for such a productive site, compared to the surrounding HNLC areas. The difference might reflect the fact that lateral advection is neglected in this model. Taking this advection into account allows the reconstruction of the observed 230Thxs linear distributions, but only if faster settling velocities are considered. This implies that the 1D model strongly underestimates the settling velocity of the particles. In the deep layers, the occurrence of intense boundary scavenging along the escarpment due to bottom sediment re-suspension and interaction with a nepheloid layer, yielding a removal of ?50% of the Th stock along the northwestward transect, is suggested.

Organofacies reconstruction and lipid geochemistry of sediments from the Galicia margin

Samples of Lower to middle Cretaceous rocks from ODP Sites 638, 640, and 641, drilled on the Galicia continental margin in the northeast Atlantic, have been investigated by organic geochemical methods (i.e., organic carbon determination, Rock-Eval pyrolysis, kerogen microscopy, gas chromatography, and gas chromatography/mass spectrometry) to define the Organofacies types and the depositional environments of these sediments. The results of this study fit well into the general picture drawn for the depositional history of the organic matter in Cretaceous organic-carbon-rich sediments in the North Atlantic from previous DSDP investigations. During the Valanginian to Albian, terrigenous organic carbon dominated the organic matter deposited on the Galicia continental margin. Cyclic changes in total organic carbon content were probably controlled by climatic-triggered changes in the supply of terrigenous organic matter from the nearby continent. A drastic change in depositional environment must have occurred near the Cenomanian/Turonian boundary. The preservation of large amounts of marine organic carbon in these sediments was probably caused by anoxic deep-water conditions during that time, rather than high productivity. All of the primary organic matter of the sediment samples investigated is thermally immature, as indicated by very low vitrinite reflectance values.

Aerosol concentrations measured along the track of METEOR cruise M16

During the third part of the Atlantic Expedition 1969 from 10° S to 60° N along 30° W, measurements of the complete size distribution of atmospheric aeosols over the whole size range from about 10**-7 to 10**-2 cm radius were made. This was possibe by the simultaneous operation of different methods which are critically discussed. The results obtained are the first of its kind and are of general interest despite some methodical shortcomings. North of the equator the ship passed through air masses of west African origin and the influence of Sahara dust on the Marine aerosols could be documented in a unique way. The Sahara dust component was restricted to the size range of 10**-5 to 10**-3 radius. Throughout the voyage particles up to 10**-2 radius were always found to be present, similar to findings over continents. Of special interest is the observation that the size distribution extends to very small particles, suggesting continuous aerosol production over the ocean.

Particle fluxes and in-situ particle properties measured with sediment traps and a moored camera system from 2008 - 2010 in region off Cape Blanc / NW-Africa

We compared particle data from a moored video camera system with sediment trap derived fluxes at ~1100 m depth in the highly dynamic coastal upwelling system off Cape Blanc, Mauritania. Between spring 2008 and winter 2010 the trap collected settling particles in 9-day intervals, while the camera recorded in-situ particle abundance and size-distribution every third day. Particle fluxes were highly variable (40-1200 mg m**-2 d**-1) and followed distinct seasonal patterns with peaks during spring, summer and fall. The particle flux patterns from the sediment traps correlated to the total particle volume captured by the video camera, which ranged from1 to 22 mm**3 l**-1. The measured increase in total particle volume during periods of high mass flux appeared to be better related to increases in the particle concentrations, rather than to increased average particle size. We observed events that had similar particle fluxes, but showed clear differences in particle abundance and size-distribution, and vice versa. Such observations can only be explained by shifts in the composition of the settling material, with changes both in particle density and chemical composition. For example, the input of wind-blown dust from the Sahara during September 2009 led to the formation of high numbers of comparably small particles in the water column. This suggests that, besides seasonal changes, the composition of marine particles in one region underlies episodical changes. The time between the appearance of high dust concentrations in the atmosphere and the increase lithogenic flux in the 1100 m deep trap suggested an average settling rate of 200 m d**-1, indicating a close and fast coupling between dust input and sedimentation of the material.

Weighted mean depth of zooplankton measured during various cruises to the Baltic Sea

The Baltic Sea is the largest brackish water area of the world. On the basis of the data from 16 cruises, we show the seasonal and vertical distribution patterns of the appendicularians Fritillaria borealis, Oikopleura dioica and the cyclopoid copepod Oithona similis, in the highly stratified Bornholm Basin. These species live at least temporarily below the permanent halocline and use different life strategies to cope with the brackish environment. The cold-water species F. borealis is abundant in the upper layers of the water column before the thermocline develops. With the formation of the thermocline abundance decreases and the specimens outlast higher temperatures below the halocline. Distribution and strategy suggest that F. borealis might be a glacial relict species in the Baltic Sea. Although Oikopleura dioica is only abundant during summer, O. similis is present all year round. Both species have in common that their vertical distribution is restricted to the waters below the halocline, most likely due to their requirements of higher salinities. We argue that the observed strategies are determined by ecophysiological constraints and life history traits. These species share an omnivorous feeding behaviour and the capability to utilise a spectra of small particles as food. As phytoplankton concentration is negligible below the halocline, we suggest that these species feed on organic material and heterotrophic organisms that accumulate in the density gradient of the halocline. Therefore, the deep haline waters in the Baltic Sea represent a habitat providing shelter from predation and food supply for adapted species that allows them to gather sufficient resources and to maintain populations.

Comparison of TEX86 and UK'37 temperature proxies in sinking particles in the Cariaco Basin

The Cariaco Basin, a silled, permanently anoxic basin on the continental shelf of Venezuela with a dynamic chemocline (-240-350 m), has been subject of > 20 years of oceanographic observation and sediment trap studies. We evaluated UK'37 and the TEX86 temperature proxies using sinking particles collected in shallow sediment trap samples at 275 m (Trap A) and 455 m (Trap B) (within and below the chemocline). The organic geochemical temperature proxies, UK'37. (based on coccolithophorid alkenone lipids) and TEX86 (based on archaeal glycerol dialkyl glycerol tetraether (GDGT) lipids), use observed relationships between the ratio of specific lipids and measured sea surface temperature to hindcast past sea surface temperatures. In this study, both UK'37 and TEX86 temperature proxies record seasonal temperature variations, including the cooling associated with upwelling events. UK'37-based temperatures are colder than measured sea surface temperatures, and better correlated temperature at the chlorophyll maximum. In sediment trap material collected below the chemocline (Trap B), UK'37 values are higher than those in Trap A. Warmer subchemocline UK'37 based temperatures may be related to autooxidation of sinking particles, either by small amounts of available oxygen or by alternate electron acceptors concentrated in the biologically dynamic chemocline (e.g. intermediate sulfur compounds). The absolute flux weighted TEX86 temperature values measured in sinking particles from Trap A match the measured SST well. The differences in the TEX86 values between Traps A and B are small and reflect less impact of degradation. Overall, the TEX86 temperatures in sinking particles in the Cariaco Basin reflect annual SST.

(Tables 1, 3) Component composition of organic particles in samples from ODP Site 131-808

Analysis of the palynofacies and miospore thermal alteration indices (TAI) of sediments from ODP Site 808 in the Nankai Trough was undertaken to determine (1) the source, depositional environment, and diagenesis of organic matter in the accreted sediments, and (2) the thermal structure and history of the prism and its relationship to fluid flow. Using the Hartax classification system, two palynofacies were recognized in the sedimentary sequence. Facies 1 occurs within the upper 600 m of trench-wedge turbidites (sedimentation rate > 1 km/m.y.) and contains >50% inertite particles. The rest of the assemblage is dominated by well-preserved phytoclasts and contains small amounts of poorly preserved phytoclasts and well-preserved scleratoclasts. Facies 2 occurs within the Shikoku Basin hemipelagites (600-1300 m below seafloor; sedimentation rate <150 m/m.y.) and contains over two-thirds inertite particles. The rest of the assemblage is dominated by poorly preserved phytoclasts. Miospores and marine phytoplankton compose only a small percentage of both palynofacies. Degraded organic matter is most noticeable in Facies 2, whereas its presence in Facies 1 is overshadowed by the high influx of well-preserved primary organic matter. Most of the degraded organic matter and inertite is interpreted to be reworked. Some of the degraded organic matter may be primary, and may have experienced more biodegradation and thermal alteration in Facies 2 than in Facies 1. TAI values indicate an immature stage of organic maturation (< 2) down to about 900 mbsf. Below this, samples show an increase with depth to a mature stage, reaching peak levels of about 3 just above basement. Samples from within the thrust fault and decollement zones do not show levels of maturity significantly greater than those of surrounding samples, leaving uncertain whether hot fluids have migrated along these fault boundaries in the past.