Early Holocene history of the Baltic Sea, as reflected in coastal sediments in Blekinge, southeastern Sweden

Integrated palaeoecological studies of two fiord sediment sequences in the province of Blekinge, SE Sweden, covering the time span 11,000–5000 cal BP, reveal the timing and the environment for the Ancylus Lake/Littorina Sea transition 9800–8500 cal BP. The first ingression of saline water into the Baltic Sea through the Danish Straits occurred earlier than formerly assumed. New evidence, particularly mineral magnetic and palaeobotanical analyses, demonstrate that on the general trend of the eustatically caused Littorina transgression several minor fluctuations of the water level can be identified between 8500 and 5000 cal years BP. A distinct regression phase around 8100 cal BP is correlated with the Greenland ice-core cold event dated to 8200 ice-core years BP. This is described as a regional climatic catastrophe for the Baltic Sea region. The coastal stratigraphy is compared with the offshore stratigraphy earlier studied. A tentative shore displacement curve for Early and Middle Holocene is presented.     

Intercomparison of shipboard and moored CARIOCA buoy seawater fCO2 measurements in the Sargasso Sea

The ocean is an important sink for carbon and heat, yet high-resolution measurements of biogeochemical properties relevant to global climate change are being made only sporadically in the ocean at present. There is a growing need for automated, real-time, long-term measurements of CO₂ in the ocean using a network of sensors, strategically placed on ships, moorings, free-drifting buoys and autonomous remotely operated vehicles. The ground-truthing of new sensor technologies is a vital component of present and future efforts to monitor changes in the ocean carbon cycle and air–sea exchange of CO₂.A comparison of a moored Carbon Interface Ocean Atmosphere (CARIOCA) buoy and shipboard fugacity of CO₂ (fCO₂) measurements was conducted in the western North Atlantic during two extended periods (>1 month) in 1997. The CARIOCA buoy was deployed on the Bermuda Testbed Mooring (BTM), which is located 5 km north of the site of the US Joint Global Ocean Flux Study (JGOFS) Bermuda Atlantic Time-series Study (BATS). The high frequency of sampling revealed that temperature and fCO₂ responded to physical forcing by the atmosphere on timescales from diurnal to 4–8 days. Concurrent with the deployments of the CARIOCA buoy, frequent measurements of surface fCO₂ were made from the R/V Weatherbird II during opportunistic visits to the BTM and BATS sites, providing a direct calibration of the CARIOCA buoy fCO₂ data. Although, the in situ ground-truthing of the CARIOCA buoy was complicated by diurnal processes, sub-mesoscale and fine-scale variability, the CARIOCA buoy fCO₂ data was accurate within 3±6 μatm of shipboard fCO₂ data for periods up to 50 days. Longer-term assessments were not possible due to the CARIOCA buoy breaking free of the BTM and drifting into waters with different fCO₂-temperature properties. Strategies are put forward for future calibration of other in situ sensors.     

A missing piece from a bigger puzzle: declining occurrence of a transient group of bottlenose dolphins off Southeastern Brazil

Bottlenose dolphins are widespread off South America with patchy distributions throughout coastal, nearshore and offshore waters. Only limited information on the connectivity between individuals from these different habitats exists, despite the importance of understanding the overall population structure. A group of bottlenose dolphins in an insular habitat off Brazil may help provide evidence of the structure of a larger pelagic population in Brazilian waters. It is unknown whether the dolphins that use this habitat seasonally are part of an open population, a closed population of transient animals, or even individuals from offshore or nearshore groups. To explore the nature of these seasonal visitors we combined two strategies. First, by assessing the population parameters, we described a small group of individuals (maximum of 38 individuals in 2004 and five individuals in 2010) characterized by wide‐ranging behavior, low survival probabilities (64%) and an apparent population decline. Secondly, by exploring their social organization at a fine scale, we observed that within a stable group, the dyadic associations are fluid and mostly of short duration, similar to well‐known coastal bottlenose dolphin societies. The evidence of a non‐structured social network seems to be coupled with apparent seasonal use of this insular protected area for calf rearing and/or reproductive strategies. Overall, our findings suggest that this group may not be an aggregation of individuals from different populations in a specific area, but a relatively stable group formed by the same animals. While continuing research efforts are necessary along the South America coast, the abandonment of the study area by this group may hamper the understanding of population structure and connectivity among pelagic and coastal populations of bottlenose dolphins, as well as the ecological and behavioral mechanisms driving their seasonal occurrence in oceanic habitats.     

Contributions to reference systems from Lunar Laser Ranging using the IfE analysis model

Lunar Laser Ranging (LLR) provides various quantities related to reference frames like Earth orientation parameters, coordinates and velocities of ground stations in the Earth-fixed frame and selenocentric coordinates of the lunar retro-reflectors. This paper presents the recent results from LLR data analysis at the Institut für Erdmessung, Leibniz Universität Hannover, based on all LLR data up to the end of 2016. The estimates of long-periodic nutation coefficients with periods between 13.6 days and 18.6 years are obtained with an accuracy in the order of 0.05–0.7 milliarcseconds (mas). Estimations of the Earth rotation phase \(\Delta \)UT are accurate at the level of 0.032 ms if more than 14 normal points per night are included. The tie between the dynamical ephemeris frame to the kinematic celestial frame is estimated from pure LLR observations by two angles and their rates with an accuracy of 0.25 and 0.02 mas per year. The estimated station coordinates and velocities are compared to the ITRF2014 solution and the geometry of the retro-reflector network with the DE430 solution. The given accuracies represent 3 times formal errors of the parameter fit. The accuracy for \(\Delta \)UT is based on the standard deviation of the estimates with respect to the reference C04 solution.     

Ages (U–Pb SHRIMP and LA ICPMS) and stratigraphic evolution of the Neoproterozoic volcano-sedimentary successions from the extensional Camaquã Basin,Southern Brazil

During the Ediacaran, southern Brazil was the site of multiple episodes of volcanism and sedimentation, which are best preserved in the 3000 km² Camaquã Basin. The interlayered sedimentary and volcanic rocks record tectonic events and paleoenvironmental changes in a more than 10 km-thick succession. In this contribution, we report new U–Pb and Sm–Nd geochronological constraints for the 605 to 580 Ma Bom Jardim Group, the 570 Ma Acampamento Velho Formation, and a newly-recognized 544 Ma volcanism. Depositional patterns of these units reveal the transition from a restricted, fault-bounded basin into a wide, shallow basin. The expansion of the basin and diminished subsidence rates are demonstrated by increasing areal distribution and compressed isopachs and increasing onlap of sediments onto the basement to the west. The Sm–Nd isotopic composition of the volcanic rocks indicates mixed sources, including crustal rocks from the adjacent basement. Both Neoproterozoic and Paleoproterozoic sources are indicated for the western part of the basin, whereas only the older Paleoproterozoic signature can be discerned in the eastern part of the basin.     

200-m-deep earthquake swarm in Tricastin (lower Rhône Valley, France) accounts for noisy seismicity over past centuries

In the lower Rhône Valley (France), the Tricastin area was struck in 2002–2003 by an earthquake swarm with a maximum M _L-magnitude of 1.7. These shocks would have gone unnoticed if they had not occurred beneath habitations and close to the surface, some events being only 200-m deep. A several months' monitoring of the seismic activity by a 16-station mobile network showed that earthquakes clustered along a N–S-trending, at least 5-km long, shallow rupture zone, with no corresponding fault mapped in the surface. Half of the seismic events occurred in a massive, c.  250-m-thick, Lower Cretaceous limestone slab that outcrops near by. Since the late eighteenth century, several much more severe earthquake swarms have struck Tricastin. The 1772–1773 and 1933–1936 swarms were prolific and protracted, with reports of numerous detonations and even damage. Obviously, the abnormal noises that caused panic in the past centuries can be explained by the shallowness of the phenomena, a 200-m focal depth being perhaps a record value for tectonic earthquakes.     

Late Weichselian environmental change in southern Sweden and Denmark

A synthesis is presented of the envronmental and climatic variations that are inferred to have occurred in southern Sweden (up to latitude 59°N) and Denmark during the Weichselian Late-glacial (14-9 ka BP). The chronology and characteristics of the main phases of deglaciation, sea-level change, periglacial activity, soil development, vegetation cover and climate change are summarised. A curve representing the main changes in temperature, including quantitative estimates based upon beetle data and using the ‘mutual climatic range’ method, is presented.