Enzyme activity, body measures and heart mass of Sepia officinalis sampled in the English Channel and Adriatic Sea

In the eurythermal cuttlefish Sepia officinalis, performance depends on hearts that ensure systemic oxygen supply over a broad range of temperatures. We therefore aimed to identify adjustments in energetic cardiac capacity and underlying mitochondrial function supporting thermal acclimation and adaptation that could be crucial for the cuttlefish's competitive success in variable environments. Two genetically distinct cuttlefish populations were acclimated to 11, 16 and 21°C. Subsequently, skinned and permeabilised heart fibres were used to assess mitochondrial functioning by means of high-resolution respirometry and a substrate-inhibitor protocol, followed by measurements of cardiac citrate synthase and cytosolic enzyme activities. Temperate English Channel cuttlefish had lower mitochondrial capacities but larger hearts than subtropical Adriatic cuttlefish. Warm acclimation to 21°C decreased mitochondrial complex I activity in Adriatic cuttlefish and increased complex IV activity in English Channel cuttlefish. However, compensation of mitochondrial capacities did not occur during cold acclimation to 11°C. In systemic hearts, the thermal sensitivity of mitochondrial substrate oxidation was high for proline and pyruvate but low for succinate. Oxygen efficiency of catabolism rose as temperature changed from 11 to 21°C via shifts to oxygen-conserving oxidation of proline and pyruvate and via reduced relative proton leak. The changes observed for substrate oxidation, mitochondrial complexes, relative proton leak and heart mass improve energetic efficiency and essentially seem to extend tolerance to high temperatures and reduce associated tissue hypoxia. We conclude that cuttlefish sustain cardiac performance and, thus, systemic oxygen delivery over short- and long-term changes of temperature and environmental conditions by multiple adjustments in cellular and mitochondrial energetics.

(Table 1) Grain size parameters of intertidal channel sand bars near Sylt, North-Frisian Wadden Sea

The aim of the present study is to investigate directional asymmetric properties and internal structures of the bedforms on the intertidal sand bars in comparison with the migration problems of the sand bodies developed in the channel systems of the tidal basin off the west coast of Schleswig-Holstein. The tidal channel sand bodies studied have 'V'-shaped outlines and are asymmetric in cross-section. Based on such knowledge it was hoped to understand and find possible factors for application to recent and ancient tidal depositional environments. The V-shaped intertidal channel sand bodies developed in the tidal environments between Sylt and Föhr Island are constantly migrating sand bars. The migration directions are in good agreement with the resultant vector mean directions of internal cross-stratification structures of asymmetric sedimentary bedforms. Finally, it is shown that the orientation of the apex of V-shaped sand bar as an equilibrium form alone can not indicate the migration direction, but that the orientation of the resultant vector mean of internal structures of sedimentary bedforms does indicate the migration direction. Based on the analyses of textural parameters of the migrating intertidal bar sands, it seems that sands of typical intertidal sand bars are negatively skewed and well sorted. The high rounding of quarz sand grains of these tidal channel sand bars seems to be an additional characteristical criterion for tidal depositional environments, as also indicated by Balazs and Klein (1972).

Air concentration of polybrominated diphenyl ethers around the Great Lakes and the Arctic

Atmospheric PBDEs were measured on a monthly basis in 2002-2004 at Point Petre, a rural site in the Great Lakes. Average air concentrations were 7.0 ± 13 pg/m**3 for the sum of 14BDE (excluding BDE-209), and 1.8 ± 1.5 pg/m**3 for BDE-209. Concentrations of 3 dominant congeners (i.e., BDE-47, 99, and 209) were comparable to previous measurements at remote/rural sites around the Great Lakes, but much lower than those at urban areas. Weak temperature dependence and strong linear correlations between relatively volatile congeners suggest importance of advective inputs of gaseous species. The significant correlation between BDE-209 and 183 implies their transport inputs associated with particles. Particle-bound percentages were found greater for highly brominated congeners than less brominated ones. These percentages increase with decreasing ambient temperatures. The observed gas/particle partitioning is consistent with laboratory measurements and fits well to the Junge-Pankow model. Using air mass back-trajectories, atmospheric transport to Point Petre was estimated as 76% for BDE-47, 67% for BDE-99, and 70% for BDE-209 from west-northwest and southwest directions. During the same time period, similar congener profiles and concentration levels were found at Alert in the Canadian High Arctic. Different inter-annual variations between Point Petre and Alert indicate that emissions from other regions than North America could also contribute PBDEs in the Arctic. In contrast to weak temperature effect at Point Petre, significant temperature dependence in the summertime implies volatilization emissions of PBDEs at Alert. Meanwhile, episodic observations in the wintertime were likely associated with enhanced inputs through long-range transport during the Arctic Haze period.

(Table 1) Mean temperatures in january and july, and total annual snowfall at Great Bear Lake and Great Slave Lake, Canada

The sensitivity of brightness temperature (T(B)) at 6.9, 10.7, and 18.7 GHz from Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) observations is investigated over five winter seasons (2002-2007) on Great Bear Lake and Great Slave Lake, Northwest Territories, Canada. The T(B) measurements are compared to ice thicknesses obtained with a previously validated thermodynamic lake ice model. Lake ice thickness is found to explain much of the increase of T(B) at 10.7 and 18.7 GHz. T(B) acquired at 18.7 GHz (V-pol) and 10.7 GHz (H-pol) shows the strongest relation with simulated lake ice thickness over the period of study (R**2 > 0.90). A comparison of the seasonal evolution of T(B) for a cold winter (2003-2004) and a warm winter (2005-2006) reveals that the relationship between T(B) and ice growth is stronger in the cold winter (2003-2004). Overall, this letter shows the high sensitivity of T(B) to ice growth and, thus, the potential of AMSR-E mid-frequency channels to estimate ice thickness on large northern lakes.

Distribution of euphausiids (Crustacea) at the Great Meteor seamount, Atlantic Ocean

In the course of the voyages 9a and 9c (1967) and 19 (1970) of the RV "Meteor" samples of plankton and neuston have been taken in the area of the Great Meteor Seamount. The euphausiids of this material have been examined quantitatively as well as qualitatively in order to study the influence of the Great and Small Meteor Seamount on a vertically migrating group of plankton. 20 species could be identified. All stem from the surrounding deep water and belong to the tropical and subtropical fauna. On the plateau of the Great Meteor Seamount no indigenous species have been encountered and also the typical neritic species from the west coast off Africa are lacking. As for the euphausiids no relationships exist between the Great Meteor Seamount and the shelf area of West Africa. The dominant species around the Meteor Seamount were Euphausia brevii, Stylocheiron suhmii, E. hemigibba, S. longicorne and Thysanopoda subaequalis. Using the index of diversity (Simpson) distinct differences in the composition of species could be shown to exist between the plateau area of the Meteor Seamount and the surrounding sea. On the plateau of the Great Meteor Seamount the number of species was only 7, E. brevis and S. suhmii dominated. None of the species occurred in great numbers and none is adapted to the specific environmental conditions of the plateau of the Meteor Seamount. The fauna of the plateau is a depauperate one as compared with that of the surrounding sea. This can be explained by the fact that adult euphausiids require for their existence greater water depths than are found above the plateau of the Meteor Seamount.

Calcareous nannofossil stratigraphy and datum levels of ODP Site 182-1127, Great Australian Bight

Ocean Drilling Program (ODP) Leg 182 drilled at nine sites on the Great Australian Bight, which is located directly south of the Australian continent. Leg 182 proposed to examine the paleoceanographic evolution of a midlatitude, cool-water carbonate platform. During drilling on the Great Australian Bight, three sites (1127, 1129, and 1131) recovered highly expanded Pleistocene sections. This paper presents the detailed calcareous nannofossil biostratigraphy of the most distal site. This report should provide a useful Pleistocene biostratigraphic reference for this previously unknown area.

Megnetic susceptibility of a subtropical South Atlantic transect

The Mid-Pleistocene transition (MPT) of the global climate system, initiated by a shift towards much larger northern hemisphere ice shields at around 920 ka and ending with predominance of 100 kyr ice age cyclicity since about 640 ka, is one of the fundamental enigmas in Quaternary climate evolution. Climate proxy records not exclusively linked to global ice volume are necessary to advance understanding of the MPT. Here we present a high-resolution Pleistocene magnetic susceptibility time series of 12 sediment cores from the subtropical South Atlantic essentially reflecting dissolution driven variations in carbonate accumulation controlled by changes in deep water circulation. In addition to characteristics known from delta18O records, the data sets reveal three remarkable features intimately related to the MPT: (1) an all-Pleistocene minimum of carbonate accumulation in the South Atlantic at 920 ka, (2) a MPT interim state of reduced carbonate deposition, indicating that the MPT period may have been a discrete state of the Pleistocene deep water circulation and climate system and (3) a terminal MPT event at around 540-530 ka documented in several peculiarities such as thick laminated layers of the giant diatom Ethmodiscus rex.

Sedimentation across the Great Barrier Reef

The continental margin off northeast Australia, comprising the Great Barrier Reef (GBR) platform and Queensland Trough, is the largest tropical mixed siliciclastic/carbonate depositional system in existence. We describe a suite of 35 piston cores and two Ocean Drilling Program (ODP) sites from a 130*240 km rectangular area of the Queensland Trough, the slope and basin setting east of the central GBR platform. Oxygen isotope records, physical property (magnetic susceptibility and greyscale) logs, analyses of bulk carbonate content and radiocarbon ages at these locations are used to construct a high resolution stratigraphy. This information is used to quantify mass accumulation rates (MARs) for siliciclastic and carbonate sediments accumulating in the Queensland Trough over the last 31,000 years. For the slope, highest MARs of siliciclastic sediment occur during transgression (1.0 Million Tonnes per year; MT/yr), and lowest MARs of siliciclastic (<0.1 MT/yr) and carbonate (0.2 MT/yr) sediment occur during sea level lowstand. Carbonate MARs are similar to siliciclastic MARs for transgression and highstand (1.1-1.4 MT/yr). In contrast, for the basin, MARs of siliciclastic (0-0.1 MT/yr) and carbonate sediment (0.2-0.4 MT/yr) are continuously low, and within a factor of two, for lowstand, transgression, and highstand. Generic models for carbonate margins predict that maximum and minimum carbonate MARs on the slope will occur during highstand and lowstand, respectively. Conversely, most models for siliciclastic margins suggest maximum and minimum siliciclastic MARs will occur during lowstand and transgression, respectively. Although carbonate MARs in the Queensland Trough are similar to those predicted for carbonate depositional systems, siliciclastic MARs are the opposite. Given uniform siliciclastic MARs in the basin through time, we conclude that terrigenous material is stored on the shelf during sea level lowstand, and released to the slope during transgression as wave driven currents transport shelf sediment offshore.