qPCR counts of mRNA for hepatic reference gene selection in adult female Atlantic salmon from perturbation experiments under artificial temperature conditions

The dataset contains raw data (quantification cycle) for a study which determined the most suitable hepatic reference genes for normalisation of qPCR data orginating from adult (entire reproductive season) Atlantic salmon (14 days) exposed to 14 and 22 degrees C. These results will be useful for anyone wanting to study the effects of climate change/elevated temperature on reproductive physiology of fish (and perhaphs other vertebrates). In addition, a target gene (vitellogenin) has normalised using an inappropriate and an 'ideal' reference gene to demonstrate the consequences of using an unstable reference gene for normalisation. For the adult experiment, maiden and repeat adult females were held at the Salmon Enterprises of Tasmania (SALTAS) Wayatinah Hatchery (Tasmania, Australia) at ambient temperature and photoperiod in either 200 (maidens) or 50 (repeats) m3 circular tanks at stocking densities of 12-18, and 24-36 kg m-3 for maidens and repeats, respectively, until transfered to the experimental tanks.

Stareso MedSeA mesocosm experiment: field and perturbation studies 2012

A joint mesocosm experiment took place in June/July 2012 in Corsica (bay of Calvi, Stareso station;http://www.stareso.com/) as part of the european MedSeA project. Nine mesocosms (52 m**3) were deployed over a 20 days period and 6 different levels of pCO2 and 3 control mesocosms (about 450 µatm), were used, in order to cover the range of pCO2 anticipated for the end of the present century. During this experiment, the potential effects of these perturbations on chemistry, planktonic community composition and dynamics including: eucaryotic and prokaryotic species composition, primary production, nutrient and carbon utilization, calcification, diazotrophic nitrogen fixation, organic matter exudation and composition, micro-layer composition and biogas production were studied by a group of about 25 scientists from 8 institutes and 6 countries. This is one of the first mesocosm experiments conducted in oligotrophic waters. A blog dedicated to this experiment can be viewed at: http://medseastareso2012.wordpress.com/.

Amino acid racemization of Neogloboquadrina pachyderma from the Arctic Ocean

The long-term rate of racemization for amino acids preserved in planktonic foraminifera was determined by using independently dated sediment cores from the Arctic Ocean. The racemization rates for aspartic acid (Asp) and glutamic acid (Glu) in the common taxon, Neogloboquadrina pachyderma, were calibrated for the last 150 ka using 14C ages and the emerging Quaternary chronostratigraphy of Arctic Ocean sediments. An analysis of errors indicates realistic age uncertainties of about ±12% for Asp and ±17% for Glu. Fifty individual tests are sufficient to analyze multiple subsamples, identify outliers, and derive robust sample mean values. The new age equation can be applied to verify and refine age models for sediment cores elsewhere in the Arctic Ocean, a critical region for understanding the dynamics of global climate change.

Table A1 LA-ICP-MS zircon U-Pb data of Laoniushan granitoids

The NWW-striking Qinling Orogen formed in the Triassic by collision between the North China and Yangtze Cratons. Triassic granitoid intrusions, mostly middle- to high-K, calc-alkaline in composition, are widespread in this orogen, but contemporaneous intrusions are rare in the southern margin of the North China Craton, an area commonly considered as the hinterland belt of the orogen. In this paper, we report zircon U-Pb ages, elemental geochemistry, and Sr-Nd-Hf isotope data for the Laoniushan granitoid complex that was emplaced in the southern margin of the North China Craton. Zircon U-Pb dating shows that the complex was emplaced in the late Triassic (228±1 to 215±4 Ma), indicating that it is part of the post-collisional magmatism in the Qinling Orogen. The complex consists of, from early to late, biotite monzogranite, quartz diorite, quartz monzonite, and hornblende monzonite, which have a wide compositional range, e.g., SiO2=55.9-70.6 wt%, K2O+Na2O=6.6-10.2 wt%, and Mg# of 24 to 54. Rocks of the biotite monzogranite have high Al2O3(15.5-17.4 wt%), Sr(396-1398 ppm) and Ba(1284-3993 ppm) contents and La/Yb(mostly 14-30) and Sr/Y(mostly 40-97) ratios, but low Yb(mostly 1.3-1.6 ppm) and Y(mostly14-19 ppm) contents, features typical of adakite. The quartz monzonite, hornblende monzonite and quartz diorite have a shoshonitic affinity, with K2O up to 5.58 wt% and K2O/Na2O ratios averaging 1.4. The rocks are characterized by strong LREE/HREE fractionation in chondrite-normalized REE pattern, without obvious Eu anomalies, and show enrichment in large ion lithophile elements but depletion in high field strength elements (Nb, Ta, Ti). The biotite monzogranite (228 Ma) has initial 87Sr/86Sr ratios of 0.7061 to 0.7067, eNd(t) values of -9.2 to -12.6, and ?Hf(t) values of -9.0 to -15.1; whereas the shoshonitic granitoids (mainly 217-215 Ma) have similar initial 87Sr/86Sr ratios (0.7065 to 0.7075) but more radiogenic eNd(t) (-12.4 to -17.0) and eHf(t) (-14.1 to -17.0). The Sr-Nd-Hf isotope data indicate that the rocks were likely generated by partial melting of an ancient lower continental crust with heterogeneous compositions, as partly confirmed by the widespread presence of the early Paleoproterozoic inherited zircons. Mafic microgranular enclaves (MMEs), characterized by fine-grained igneous textures and an abundance of acicular apatites, are common in the Laoniushan complex. Compared with the host rocks, they have lower SiO2 (48.6-53.7 wt.%) and higher Mg# (51-56), Cr (122-393 ppm), and Ni (24-79 ppm), but equivalent Sr-Nd isotope compositions, indicating that the MMEs likely originated from an ancient enriched lithospheric mantle. The abundance of MMEs in the granitoid intrusions suggests that magma mixing plays an important role in the generation of the Laoniushan complex. Collectively, it is suggested that the Laoniushan complex was a product of post-collisional magmatism related to lithospheric extension following slab break-off. Formation of the adakitic and shoshonitic intrusions in the Laoniushan complex indicates that the Qinling Orogen had evolved into a post-collisional setting by about 230-210 Ma.

Morphological plasticity of the coral skeleton under CO2-driven seawater acidification

Ocean acidification causes corals to calcify at reduced rates, but current understanding of the underlying processes is limited. Here, we conduct a mechanistic study into how seawater acidification alters skeletal growth of the coral Stylophora pistillata. Reductions in colony calcification rates are manifested as increases in skeletal porosity at lower pH, while linear extension of skeletons remains unchanged. Inspection of the microstructure of skeletons and measurements of pH at the site of calcification indicate that dissolution is not responsible for changes in skeletal porosity. Instead, changes occur by enlargement of corallite-calyxes and thinning of associated skeletal elements, constituting a modification in skeleton architecture. We also detect increases in the organic matrix protein content of skeletons formed under lower pH. Overall, our study reveals that seawater acidification not only causes decreases in calcification, but can also cause morphological change of the coral skeleton to a more porous and potentially fragile phenotype.

Changes in coral reef communities across a natural gradient in seawater pH

Ocean acidification threatens the survival of coral reef ecosystems worldwide. The negative effects of ocean acidification observed in many laboratory experiments have been seen in studies of naturally low-pH reefs, with little evidence to date for adaptation. Recently, we reported initial data suggesting that low-pH coral communities of the Palau Rock Islands appear healthy despite the extreme conditions in which they live. Here, we build on that observation with a comprehensive statistical analysis of benthic communities across Palau's natural acidification gradient. Our analysis revealed a shift in coral community composition but no impact of acidification on coral richness, coralline algae abundance, macroalgae cover, coral calcification, or skeletal density. However, coral bioerosion increased 11-fold as pH decreased from the barrier reefs to the Rock Island bays. Indeed, a comparison of the naturally low-pH coral reef systems studied so far revealed increased bioerosion to be the only consistent feature among them, as responses varied across other indices of ecosystem health. Our results imply that whereas community responses may vary, escalation of coral reef bioerosion and acceleration of a shift from net accreting to net eroding reef structures will likely be a global signature of ocean acidification.

14C sedimentation rates and benthic mixing of equatorial Pacific sediments

Carbon-14 determinations on box cores of calcareous ooze from the western and eastern equatorial Pacific suggest that patterns of mixed-layer ages, sedimentation rates, and mixed-layer thicknesses are controlled by gradients of carbonate dissolution and fertility, and by small-scale redeposition processes. Mixed-layer ages range from 3000 to 7000 years, with a mode between 4000 and 5000 years. Sedimentation rates range from 0.8 to 2.4 cm/1000 years. Mixed-layer depths, calculated according to the box model of mixing, range from 7 cm to 16 cm. Observed thicknesses are about one-fourth smaller than calculated ones.

Age determination and carbonate content of sediment core KH-79-3_L3

Laminated sediments deposited under anoxic bottom waters in the Japan Sea during the last glacial maximum (LGM) contain extremely well preserved calcareous microfossils and eolian carbonates. The radiocarbon age-difference between bulk sediment and monospecific planktonic foraminifera in discrete laminae from a core in the southern Japan Sea implies that ~40% of the total carbonates in the sediments at the LGM are of eolian origin. Extrapolation of this result yields a rate of supply of eolian carbonates of ~2800 tons/d to the entire Japan Sea during the LGM. The climatic significance of this flux potentially lies in its broader geographic extension, particularly in the interaction of the carbonate-bearing dust with shallow, corrosive North Pacific waters and with rain in the atmosphere. By increasing the alkalinity of such waters and by enhancing the biological pump the dust flux could have increased CO2 absorption by both the ocean and rain during the LGM.

Chronology and petrology in MIS4-2 of DSDP Site 94-609

Ice-rafting evidence for a '1500-year cycle' sparked considerable debate on millennial-scale climate change and the role of solar variability. Here, we reinterpret the last 70,000 years of the subpolar North Atlantic record, focusing on classic DSDP Site 609, in the context of newly available raw data, the latest radiocarbon calibration (Marine09) and ice core chronology (GICC05), and a wider range of statistical methodologies. A ~1500-year oscillation is primarily limited to the short glacial Stage 4, the age of which is derived solely from an ice flow model (ss09sea), subject to uncertainty, and offset most from the original chronology. Results from the most well-dated, younger interval suggest that the original 1500 ± 500 year cycle may actually be an admixture of the ~1000 and ~2000 cycles that are observed within the Holocene at multiple locations. In Holocene sections these variations are coherent with 14C and 10Be estimates of solar variability. Our new results suggest that the '1500-year cycle' may be a transient phenomenon whose origin could be due, for example, to ice sheet boundary conditions for the interval in which it is observed. We therefore question whether it is necessary to invoke such exotic explanations as heterodyne frequencies or combination tones to explain a phenomenon of such fleeting occurrence that is potentially an artifact of arithmetic averaging.

Radiocarbon ages and diatom isotope data for Lake El'gygytgyn sediment core Lz1029

Determining the response of sites within the Arctic Circle to long-term climatic change remains an essential pre-requisite for assessing the susceptibility of these regions to future global warming and Arctic amplification. To date, existing records from North East Russia have demonstrated significant spatial variability across the region during the late Quaternary. Here we present diatom d18O and d30Si data from Lake El'gygytgyn, Russia, and suggest environmental changes that would have impacted across West Beringia from the Last Glacial Maximum to the modern day. In combination with other records, the results raise the potential for climatic teleconnections to exist between the region and sites in the North Atlantic. The presence of a series of 2-3 per mil decreases in d18Odiatom during both the Last Glacial and the Holocene indicates the sensitivity of the region to perturbations in the global climate system. Evidence of an unusually long Holocene thermal maximum from 11.4 ka BP to 7.6 ka BP is followed by a cooling trend through the remainder of the Holocene in response to changes in solar insolation. This is culminated over the last 900 years by a significant decrease in d18Odiatom of 2.3 per mil, which may be related to a strengthening and easterly shift of the Aleutian Low in addition to possible changes in precipitation seasonality.

Radiogenic isotope trace composition of the Labrador Sea

Geological reconstructions and general circulation models suggest that the onset of both Northern Hemisphere glaciation, 2.7 Myr ago, and convection of Labrador Sea Water (LSW) were caused by the closure of the Panama Gateway ~4.5 Myr ago. Time series data that have been obtained from studies of ferromanganese crusts from the northwestern Atlantic suggest that radiogenic isotopes of intermediate ocean residence time (Pb and Nd) can serve as suitable tracers to reconstruct these events. However, it has been unclear until now as to whether the changes that have been observed in isotope composition at this time are the result of increased thermohaline circulation or due to the effects of increased glacial weathering. In this paper we adopt a box model approach to demonstrate that the shifts in radiogenic isotope compositions are unlikely to be due to changes in convection in LSW but can be explained in terms of increases of erosion levels due to the glaciation of Greenland and Canada. Furthermore, we provide experimental evidence for the incongruent release of a labile fraction of strongly radiogenic Pb and nonradiogenic Nd from continental detritus eroding into the Labrador Sea. This can be attributed to the glacial weathering of old continents and accounts for the paradox that one of the areas of the world most deficient in radiogenic Pb should provide such a rich supply of radiogenic Pb to the oceans. An important general conclusion is that the compositions of radiogenic isotopes in seawater are not always a reflection of their continental sources. Perhaps more importantly, the transition from chemical weathering to mechanical erosion is likely to result in significant variations in radiogenic tracers in seawater.

Metabolic rates and tissue composition of the coral Pocillopora verrucosa over 12 latitudes in the Red Sea characterized by strong temperature and nutrient gradient

Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo-tolerant populations in warmer regions. Here, we investigated seasonal changes in the in situ metabolic performance of the widely distributed hermatypic coral Pocillopora verrucosa along 12 degrees latitudes featuring a steep temperature gradient between the northern (28.5 degrees N, 21-27 degrees C) and southern (16.5 degrees N, 28-33 degrees C) reaches of the Red Sea. Surprisingly, we found little indication for regional adaptation, but strong indications for high phenotypic plasticity: Calcification rates in two seasons (winter, summer) were found to be highest at 28-29 degrees C throughout all populations independent of their geographic location. Mucus release increased with temperature and nutrient supply, both being highest in the south. Genetic characterization of the coral host revealed low inter-regional variation and differences in the Symbiodinium clade composition only at the most northern and most southern region. This suggests variable acclimatization potential to ocean warming of coral populations across the Red Sea: high acclimatization potential in northern populations, but limited ability to cope with ocean warming in southern populations already existing at the upper thermal margin for corals