Fertilisation and larval development in an Antarctic bivalve, Laternula elliptica, under reduced pH and elevated temperatures

Elevated temperatures associated with ocean warming and acidification can influence development and, ultimately, success of larval molluscs. The effect of projected oceanic changes on fertilisation and larval development in an Antarctic bivalve, Laternula elliptica, was investigated through successive larval stages at ambient temperature and pH conditions (-1.6°C and pH 7.98) and conditions representative of projections through to 2100 (-0.5°C to +0.4°C and pH 7.80 to pH 7.65). Where significant effects were detected, increased temperature had a consistently positive influence on larval development, regardless of pH level, while effects of reduced pH varied with larval stage and incubation temperature. Fertilisation was high and largely independent of stressors, with no loss of gamete viability. Mortality was unaffected at all development stages under experimental conditions. Elevated temperatures reduced occurrences of abnormalities in D-larvae and accelerated larval development through late veliger and D-larval stages, with D-larvae occurring 5 d sooner at 0.4°C compared to ambient temperature. Reduced pH did not affect occurrences of abnormalities in larvae, but it slowed the development of calcifying stages. More work is required to investigate the effects of developmental delays of the magnitude seen here in order to better determine the ecological relevance of these changes on longer term larval and juvenile success.

Experiment: summer mortality phenomena in pacific oysters

Mass mortalities of Pacific oysters Crassostrea gigas occur regularly when temperatures are high. Elevated temperatures facilitate the proliferation and spread of pathogens and simultaneously impose physiological stress on the host. Additionally, periods of high temperatures coincide with the oyster spawning season. Spawning is energetically costly and can further compromise oyster immunity. Most studies monitoring the underlying factors of oyster summer mortality in the field, point to the involvement of abiotic and biotic factors including low salinities, high temperatures, pollutants, toxic algae blooms, pathogen exposure and physical stress in conjunction with maturation. However, studies addressing more than two factors experi- mentally are missing thus far. Therefore, we investigated the combination of three main factors including abiotic as well as internal and external biotic stressors by conducting controlled infection experiments on pre-and post-spawning as well as on gravid oysters with opportunistic Vibrio sp. at two different tempera- tures. Based on mortality rates, infection intensity and cellular immune parameters, we provide experimental evidence that all three factors (i.e. reproductive investment, elevated temperatures and infection with oppor- tunistic Vibrio sp.) act additively to the phenomenon of oyster summer mortality, leaving post-spawning oyster more susceptible to SMS than pre-spawning and gravid oysters. While previous studies found that post-spawning oysters have a lower thermal tolerance and a reduced ability to withstand pathogen infec- tions, our study now allows to separate the relative contribution of different causative agents to oyster sum- mer mortality and pinpoint to infection with pathogenic Vibrio sp. being of highest importance. In addition we can add a mechanistic understanding for the higher losses after spawning during which the phagocytic ability of hemocytes was strongly impeded resulting in insufficient clearance of pathogens.

(Table 1) Mineralogy of veins in basalts at DSDP Hole 61-462A

Numerous veins are present in basalts recovered from Hole 462A, Leg 61 of the Deep Sea Drilling Project. Three mineral assemblages are recognized and stratigraphically controlled. These assemblages are (1) a zeolite-bearing, quartz-poor assemblage which occurs from Core 44 to the bottom of the hole and contains smectite, clinoptilolite, calcite, pyrite, ± chabazite, ± analcime, ± quartz, ± apophyllite, ± talc (?); (2) a quartz-rich, pyrite-bearing assemblage, found between Cores 19 and 29, which contains smectite, calcite, quartz, and pyrite; and (3) a quartz-rich, celadonite-bearing assemblage which occurs from Cores 14 through 17 and contains smectite, calcite, quartz, celadonite, and Fe oxide. These data are interpreted to represent two episodes of vein mineral formation with an oxidative overprint on the more recent. The first episode followed the outpourings of basaltic lavas onto the sea floor. Zeolite-bearing veins were formed at elevated temperatures under low PCO2 while the thermal gradient was high and before a cover of calcareous sediments had formed. The second mineralization episode followed injection of basalt and microdiabase sills into a thick layer of sediments, and produced all the vein minerals now occurring between Cores 14 and 29. These veins formed at lower temperature and higher PCO2 than zeolite-bearing veins. The presence of pyrite indicates a nonoxidative environment. After the initial formation of these veins, oxygenated seawater diffused through the sedimentary cover and oxidized the pyrite and smectite, forming celadonite and Fe oxides.

Trematomus bernacchii experimental data files

As a response to ocean warming, shifts in fish species distribution and changes in production have been reported that have been partly attributed to temperature effects on the physiology of animals. The Southern Ocean hosts some of the most rapidly warming regions on earth and Antarctic organisms are reported to be especially temperature sensitive. While cellular and molecular organismic levels appear, at least partially, to compensate for elevated temperatures, the consequences of acclimation to elevated temperature for the whole organism are often less clear. Growth and reproduction are the driving factors for population structure and abundance. The aim of this study was to assess the effect of long-term acclimation to elevated temperature on energy budget parameters in the high-Antarctic fish Trematomus bernacchii. Our results show a complete temperature compensation for routine metabolic costs after 9 weeks of acclimation to 4°C. However, an up to 84% reduction in mass growth was measured at 2 and 4°C compared with the control group at 0°C, which is best explained by reduced food assimilation rates at warmer temperatures. With regard to a predicted temperature increase of up to 1.4°C in the Ross Sea by 2200, such a significant reduction in growth is likely to affect population structures in nature, for example by delaying sexual maturity and reducing production, with severe impacts on Antarctic fish communities and ecosystems.

Interstitial-water geochemistry of Kerguelen Plateau sediments

This report synthesizes all of the interstitial-water chemistry studies associated with the Kerguelen Plateau phase of ODP Leg 119. Sediments were cored at six sites (49°24'S to 59°36'S) in water depths ranging from 564 to 4082 m. A total of 77 interstitial-water samples was recovered as part of the routine sampling protocol. In addition, a novel, highresolution pore-water sampling program was tested during Leg 119 that enabled us to pinpoint reaction zones and extend our data base to deeper, drier levels that were heretofore inaccessible. Data collected include interstitial-water sodium, potassium, calcium, magnesium, pH, alkalinity, sulfate, ammonia, phosphate, aqueous silica, salinity, chloride, oxidation-reduction potentials, and sediment chemistry. The northern sector (Sites 736 and 737) is characterized by the highest sedimentation rates (up to 140 m/m.y.) and thermal gradients (70°-98°C/km) encountered on the Kerguelen Plateau during Leg 119. Site 737 represents the most reactive sediment column cored on the Kerguelen Plateau. Major cation fluxes at Site 737 are the strongest measured during Leg 119. High dissolved calcium concentrations (141.5 mM) were encountered near the bottom of Hole 737B. Elevated temperatures promote silica diagenesis and the alteration of volcanic material below 300 mbsf, and a diagenetic front was discovered near 370 mbsf at Site 737. The southern portion of the Kerguelen Plateau (Sites 738 and 744) records the lowest sedimentation rates (less than 5 m/m.y.) and thermal gradients (43°C/km) of the three study areas. Major cation fluxes at the southern sites are the lowest that we measured on the Kerguelen Plateau. High-resolution sampling provided evidence for significant silica release to the pore waters during the weathering of basement basalt. The relatively low thermal gradient does not appear to be sufficient for the formation of the opal-CT and quartz chert beds and nodules that were encountered below 120 mbsf at Site 738. Sediment-accumulation rates on the Eastern Kerguelen Sediment Ridge (Sites 745 and 746) are intermediate to those of the northern and southern sites. Deposition below the regional CCD accounts for the nearly carbonate-free, siliceous sediments. Despite their low organic carbon contents (mean = 0.15%), sediments on the Eastern Kerguelen Sediment Ridge exhibit the highest pore-water alkalinity (6.77 mM), ammonium (0.50 mM), and phosphate (23 µM) concentrations measured on the Kerguelen Plateau. Major cation fluxes are intermediate to those calculated for the northern and southern sites. The Eastern Kerguelen Sediment Ridge interstitial waters are unusual, however, in that the downward flux of magnesium is greater than the upward flux of calcium.

Characterization of diagenetic fluids at ODP Site 103-639

Site 639, drilled during Leg 103 of the Ocean Drilling Program, penetrated an Upper Jurassic to Lower Cretaceous carbonate platform on a tilted fault block along the Galicia margin off the northwest Iberian Peninsula. The carbonate platform is composed primarily of a sequence of dolomite overlying limestone. Samples were analyzed for mineral chemistry, stable isotope geochemistry, fluid inclusion microthermometry, and volatile contents and by dolomite pyrolysis mass spectrometry for trace sulfate minerals. The dolomite recovered from the Galicia margin at Site 639 formed during shallow burial from sulfate-bearing, hypersaline brines at slightly elevated temperatures. The light oxygen isotopic signatures of the dolomite are interpreted as the result of the evaporative loop and slightly elevated temperatures during dolomite formation or from reequilibration at higher temperatures during deeper burial. The hypersalinity is interpreted to be associated with a nearby, shallow restricted basin that formed during rifting of the Iberian margin from Newfoundland. The dolomitization of the platform is therefore a by-product of the rifting.

Mineralogy and geochemistry at DSDP Hole 62-465A

Core recovered from Hess Rise contains concentrations of pyrite, marcasite, and barite in the lowermost meter of limestone (Unit II) and in the brecciated upper part of the underlying volcanic basement (Unit HI). Petrographic and chemical data indicate that the sulfide-barite assemblage in the limestone is mainly a product of low-temperature diagenetic processes. The iron-sulfide phases are biogenic and their concentrations mark the diffusion of sea water sulfate through sedimentary horizons containing abundant organic matter and mafic, glassy volcanogenic detritus. There is some evidence, however, that elevated temperatures augmented or intensified the synsedimentary diagenetic process.

Strontium chemistry of anhydrite from DSDP/ODP Hole 504B

A unique record of the chemical evolution of seawater during hydrothermal recharge into oceanic crust is preserved by anhydrite from the volcanic sequences and sheeted dike complex in ODP Hole 504B. Chemical and isotopic analyses 87Sr/86Sr, delta18O, delta34S of anhydrite constrain the changing composition of fluids due to reaction with basalt. There is a general trend of decreasing 87Sr/86Sr of anhydrite, corresponding to the minor incorporation of basaltic strontium with depth in the volcanic rocks. 87Sr/86Sr ratios decrease rapidly with depth in the dikes to values identical to host basalt (0.7029). Sr/Ca ratios (<0.1 mmol/mol) suggest that recharge fluids have very low Sr concentrations and fluids evolve by first precipitating Sr-bearing phases before extensive exchange of Sr with the host basalt. There is a background trend of decreasing sulfate delta18O with depth from +12-13? in the lower volcanics to +7? in the lower sheeted dikes recording an increase in recharge fluid temperature from c. 150° to c. 250°C, and confirming the presence of sulfate in hydrothermal fluids at elevated temperatures. From the amount of anhydrite recovered from Hole 504B and the amount of seawater sulfur that has been reduced to sulfide, a minimum seawater recharge flux can be calculated. This value is 4-25 times lower than estimates of high-temperature fluid fluxes based on either thermal constraints or global chemical budgets and suggests that there is significant deficit of seawater-derived sulfur in the oceanic crust. Only a minor proportion of the seawater that percolates into the crust near the axis is heated to high temperatures and exits as black smoker-type fluids. A significant proportion of the axial heat loss must be advected at 200-250°C by sulfate-bearing hydrothermal solutions that egress diffusely from the crust. These fluids penetrate into the dikes and exchange both heat and chemical tracers without the extensive clogging of porosity by anhydrite precipitation, which would halt hydrothermal circulation for any reasonable fluid flux. The heating of the major proportion of hydrothermal fluids to only moderate temperatures (c. 250°C) reconciles estimates of hydrothermal fluxes derived from thermal models and global geochemical budgets. The flux of hydrothermal sulfate would be of a magnitude similar to the riverine input, and oxygen-isotopic exchange at 200-250°C between dissolved sulfate and recharge fluids during hydrothermal circulation provides a mechanism to continuously buffer seawater sulfate oxygen to the light isotopic composition observed.

Rates of egg production, grazing and mortatlity of Calanus finmarchicus measured experimentally in the North Atlantic during the Maria S. Merian cruise MSM26, spring 2013

An incubation experiment at five different temperatures was used to assess the potential for adaptation of Calanus finmarchicus to future warming of the ocean. During a short term (3 h) and long term (6 day) exposure of individual females to a gradient of temperature stress, egg production and fecal pellet production were monitored to indicate secondary production and grazing rates. A longer term (10 day) exposure to elevated temperatures followed by a return to ambient sea temperatures was used to assess the potential recovery of individuals exposed to temperature stress. Females were picked out from WP2 net samples and acclimatised in 2 L bottles of GFF filtered seawater with Thalassiosira weissflogii as prey for >48 h at ambient SST. Experimental bottles were filled with filtered seawater (GFF filtered from non-toxic seawater supply) and acclimated to experimental temperature overnight (0, 5, 10, 15 and 20 °C). Individual females were transferred into bottles using forceps and the bottles were inoculated with T. weissflogii to a final concentration of 5 µg chl L-1. Bottles were then placed into water baths and incubated for 3h or 6 d, and monitored for egg and fecal pellet production rates. A 10 day exposure experiment was used to test the potential for recovery from temperature stress, by returning females incubated at 5, 10, 15 and 20 °C back to 10 °C for 24 h and counting egg and fecal pellet production.

qPCR counts of mRNA for hepatic reference gene selection in juvenile 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 juvenile 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).

Authigenic carbonate of ODP SIte 104-643

Different generations of complex authigenic carbonates formed in siliceous muds (lithologic Unit IV) and hemipelagic clays (lithologic Unit V) of ODP Site 643, Leg 104 Norwegian Sea. The dominant phase in Unit IV is an early diagenetic Mn, Fe-calcite with a strong negative d13C ( -14 to -16 per mil) signature, and slightly negative d180 values. The strong negative d13C results from extensive incorporation of 12C-enriched CO2 derived from bacterial degradation of marine organic matter into early Mn, Fe - calcite cements. Concomitant framboidal pyrite precipitation and abundant SEM microtextures showing excellent preservation of delicate structures of fragile diatom valves by outpourings with early Mn-calcites strongly support their shallow burial formation before the onset of compaction. Later generations of authigenic mineralizations in lithologic Unit IV include minor amounts of a second generation of calcite with platy crystals, possibly precipitated along with opal-A dissolution, and finally opal-CT crystallization in deeper seated environments overgrowing earlier precipitates with films and lepispheres. The last mineralization is collophane (fluor apatite) forming amorphous aggregates and tiny hexagonal crystals. Authigenic mineral assemblages in lithologic Unit V consist of rhodochrosites, transitional rhodochrosite/manganosiderites, and apatite. A negative d13C ( -7.1 to -15.6 per mil) and a fluctuating d18O signal indicates that the micritic to sparitic rhodochrosites, transitional rhodochrosites/manganosiderites were formed at various burial depths. CO2 resulted from organic matter degradation in the lowermost sulfate reduction zone and from biogenic methane generation in the lowermost sediments, resulting in variable and negative d13C signals. The change in carbonate mineralogy reflects major compositional differences compared to sediments in Unit IV. Most prominent is an increase in altered ash as a primary sediment component and a sudden decrease of siliceous microfossils. Upward diffusion of cations, lowered salinities in pore waters, and elevated temperatures provide diagenetic environments favoring increased remobilization processes.

Impact of thermal stress on evolutionary trajectories of pathogen resistance in three-spined stickleback (Gasterosteus aculeatus), supplementary material

Background: Pathogens are a major regulatory force for host populations, especially under stressful conditions. Elevated temperatures may enhance the development of pathogens, increase the number of transmission stages, and can negatively influence host susceptibility depending on host thermal tolerance. As a net result, this can lead to a higher prevalence of epidemics during summer months. These conditions also apply to marine ecosystems, where possible ecological impacts and the population-specific potential for evolutionary responses to changing environments and increasing disease prevalence are, however, less known. Therefore, we investigated the influence of thermal stress on the evolutionary trajectories of disease resistance in three marine populations of three-spined sticklebacks Gasterosteus aculeatus by combining the effects of elevated temperature and infection with a bacterial strain of Vibrio sp. using a common garden experiment. Results: We found that thermal stress had an impact on fish weight and especially on survival after infection after only short periods of thermal acclimation. Environmental stress reduced genetic differentiation (QST) between populations by releasing cryptic within-population variation. While life history traits displayed positive genetic correlations across environments with relatively weak genotype by environment interactions (GxE), environmental stress led to negative genetic correlations across environments in pathogen resistance. This reversal of genetic effects governing resistance is probably attributable to changing environment-dependent virulence mechanisms of the pathogen interacting differently with host genotypes, i.e. GPathogenxGHostxE or (GPathogenxE)x(GHostxE) interactions, rather than to pure host genetic effects, i.e. GHostxE interactions. Conclusion: To cope with climatic changes and the associated increase in pathogen virulence, host species require wide thermal tolerances and pathogen-resistant genotypes. The higher resistance we found for some families at elevated temperatures showed that there is evolutionary potential for resistance to Vibrio sp. in both thermal environments. The negative genetic correlation of pathogen resistance between thermal environments, on the other hand, indicates that adaptation to current conditions can be a weak predictor for performance in changing environments. The observed feedback on selective gradients exerted on life history traits may exacerbate this effect, as it can also modify the response to selection for other vital components of fitness.

Thermal diagenesis of clay minerals within volcanogenic material from ODP Site 135-841

Clay minerals are examined in detail in the sediment from the Tonga Trench margin at Site 841 (Leg 135 ODP). The changes in amount and nature of secondary clays with depth provide an alternative explanation for the intensive alteration of volcanogenic material at convergent margins. A characteristic distribution of clay minerals with depth shows four distinct zones unexplainable by simple burial diagenesis processes. These are named the upper, reactive, lower and rhyolitic zones. The reactive zone is intercalated with numerous sills and is characterized by the dominant iron-rich clays such as saponite, corrensite and chlorite associated with analcime. The occurrence of such iron-rich clays, mostly associated with a large amount of analcime, yields chemical and mineralogical evidence for thermal diagenesis. The required heat for the diagenetic process was transferred from recently intruded basaltic andesite sills. In the vicinity of these intrusions, the iron-rich clay minerals may have formed at temperatures up to 200°C. A zoning with respect to clay and zeolite minerals indicates that the influence of the palaeoheat flow decreased with the distance from the intrusion. The formation of interlayered I/S, illite, kaolinite and aluminous chlorite, which are recognized as major secondary minerals within the rhyolitic complex, was mainly controlled by both early diagenesis at moderately elevated temperatures, and since the Eocene by burial diagenesis at low temperatures. The occurrence of a steam zone in an early stage of the intrusion is restricted to Miocene tuffs and has overprinted the early alteration of the volcanogenic material within the tuffs and has changed the originally pristine composition of the pore fluids.

Chemical and isotopic compositions of deep-sea carbonate sediments and interstitial waters from DSDP Sites 30-288 and 30-289

Interstitial waters and sediments from DSDP sites 288 and 289 contain information on the chemistry and diagenesis of carbonate in deep-sea sediments and on the role of volcanic matter alteration processes. Sr/Ca ratios are species dependent in unaltered foraminifera from site 289 and atom ratios (0.0012-0.0016) exceed those predicted by distribution coefficent data (~0.0004). During diagenesis Sr/Ca ratios of carbonates decrease and reach the theoretical distribution at a depth which is identical to the depth of Sr isotopic equilibration, where 87Sr/86Sr ratios of interstitial waters and carbonates converge. Mg/Ca ratios in the carbonates do not increase with depth as found in some other DSDP sites, possibly because of diagenetic re-equilibration with interstitial waters showing decreasing Mg(2+)/Ca(2+) ratios with depth due to Ca input and Mg removal by alteration of volcanic matter. Interstitial 18O/16O ratios increase with depth at site 289 to d18O = 0.67? (SMOW), reflecting carbonate recrystallization at elevated temperatures (>/= 20°C), the first recorded evidence of this effect in interstitial waters. Interstitial Sr2+ concentrations reach high levels, up to 1 mM, chiefly because of carbonate recrystallization. However, 87Sr/86Sr ratios decrease from 0.7092 to less than 0.7078, lower than for contemporaneous sea water, showing that there is a volcanic input of strontium at depth. This volcanic component is recorded in the Sr isotopic composition of recrystallized calcites. Isotopic compositions of the unrecrystallized calcites suggests that the rate of increase of the 87Sr/86Sr ratio of sea water with time has been faster since 3 my ago than in the preceding 13 my.

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.