Physiological and biochemical characteristics of polar cod (Boreogadus saida) from Kongsfjorden

Seasonality of biomarker baseline levels were studied in polar cod (Boreogadus saida), caught in Kongsfjorden, Svalbard, in April, July, September and December, 2006-2007. Physiological parameters (condition factor, gonado- and hepato-somatic indexes, energy reserves, potential metabolic activity and antifreeze activity) in polar cod were used to interpret the seasonality of potential biomarkers. The highest levels of ethoxyresorufin-O-deethylase (EROD) activity occurred concomitantly with the highest potential metabolic activity in July due to e.g. intense feeding. During pre-spawning, EROD showed significant inhibition and gender differences. Hence, its potential use in environmental monitoring should imply gender differentiation at least during this period. Glutathione S-transferase and catalase activities were stable from April to September, but changed in December suggesting a link to low biological activity. Knowledge of the biomarker baseline levels and their seasonal trends in polar cod is essential for a trustworthy interpretation of forthcoming toxicity data and environmental monitoring in the Arctic.

Molecular and biochemical analyses of wounding in mesocarp of peach (Prunus persica L. Batsch) ripe fruits

The physiological and molecular responses of ripe fruit to wounding were evaluated in two peach (Prunus persica) varieties ('Glohaven', GH, melting and 'BigTop', BT, slow melting nectarine) by comparing mesocarp samples from wedges (as in minimal processing) and whole fruit as the control. Slight differences between the two varieties were detected in terms of ethylene production, whereas total phenol and flavonoid concentrations, and PPO and POD enzyme activities showed a general increase in wounded GH but not in BT. This was associated with the better appearance of the BT wedges at the end of the experimental period (72 h). Microarray (genome-wide ?PEACH3.0) analysis revealed that a total number of 2218 genes were differentially expressed (p < 0.01, log2 fold change expression ratio >1 or <-1) in GH 24 h after wounding compared to the control. This number was much lower (1208) in BT. According to the enrichment analysis, cell wall, plasma membrane, response to stress, secondary metabolic processes, oxygen binding were the GO categories over-represented among the GH up-regulated genes, whereas plasma membrane and response to endogenous stimulus were the categories over-represented among the down-regulated genes. Only 32 genes showed a common expression trend in the two varieties 24 h after wounding, whereas a total of 512 genes (with highly represented transcription factors), displayed opposite behavior. Quantitative RT-PCR analysis confirmed the microarray data for 18 out of a total of 20 genes selected. Specific WRKY, AP2/ERF and HSP20 genes were markedly up-regulated in wounded GH, indicating the activation of regulatory and signaling mechanisms probably related to different hormone categories. Compared to BT, the expression of specific genes involved in phenylpropanoid and triterpenoid biosynthetic pathways showed a more pronounced induction in GH, highlighting the difference between the two peach varieties in terms of molecular responses to wounding in the mesocarp tissue.

(Table 1) Biological and chemical characteristics of surface water stations during Nathaniel B. Palmer cruise NBP06-08 to the Ross Sea

We present results from a field study of inorganic carbon (C) acquisition by Ross Sea phytoplankton during Phaeocystis-dominated early season blooms. Isotope disequilibrium experiments revealed that HCO3? was the primary inorganic C source for photosynthesis in all phytoplankton assemblages. From these experiments, we also derived relative enhancement factors for HCO3?/CO2 interconversion as a measure of extracellular carbonic anhydrase activity (eCA). The enhancement factors ranged from 1.0 (no apparent eCA activity) to 6.4, with an overall mean of 2.9. Additional eCA measurements, made using membrane inlet mass spectrometry (MIMS), yielded activities ranging from 2.4 to 6.9 U/[?g chl a] (mean 4.1). Measurements of short-term C-fixation parameters revealed saturation kinetics with respect to external inorganic carbon, with a mean half-saturation constant for inorganic carbon uptake (K1/2) of ~380 ?M. Comparison of our early springtime results with published data from late-season Ross Sea assemblages showed that neither HCO3? utilization nor eCA activity was significantly correlated to ambient CO2 levels or phytoplankton taxonomic composition. We did, however, observe a strong negative relationship between surface water pCO2 and short-term 14C-fixation rates for the early season survey. Direct incubation experiments showed no statistically significant effects of pCO2 (10 to 80 Pa) on relative HCO3? utilization or eCA activity. Our results provide insight into the seasonal regulation of C uptake by Ross Sea phytoplankton across a range of pCO2 and phytoplankton taxonomic composition.

Effects of ocean acidification on the swimming ability, development and biochemical responses of sand smelt larvae

Ocean acidification, recognized as a major threat to marine ecosystems, has developed into one of the fastest growing fields of research in marine sciences. Several studies on fish larval stages point to abnormal behaviours, malformations and increased mortality rates as a result of exposure to increased levels of CO2. However, other studies fail to recognize any consequence, suggesting species-specific sensitivity to increased levels of CO2, highlighting the need of further research. In this study we investigated the effects of exposure to elevated pCO2 on behaviour, development, oxidative stress and energy metabolism of sand smelt larvae, Atherina presbyter. Larvae were caught at Arrábida Marine Park (Portugal) and exposed to different pCO2 levels (control: 600 µatm, pH = 8.03; medium: 1000 µatm, pH = 7.85; high: 1800 µatm, pH = 7.64) up to 15 days, after which critical swimming speed (Ucrit), morphometric traits and biochemical biomarkers were determined. Measured biomarkers were related with: 1) oxidative stress-superoxide dismutase and catalase enzyme activities, levels of lipid peroxidation and DNA damage, and levels of superoxide anion production; 2) energy metabolism - total carbohydrate levels, electron transport system activity, lactate dehydrogenase and isocitrate dehydrogenase enzyme activities. Swimming speed was not affected by treatment, but exposure to increasing levels of pCO2 leads to higher energetic costs and morphometric changes, with larger larvae in high pCO2 treatment and smaller larvae in medium pCO2 treatment. The efficient antioxidant response capacity and increase in energetic metabolism only registered at the medium pCO2 treatment may indicate that at higher pCO2 levels the capacity of larvae to restore their internal balance can be impaired. Our findings illustrate the need of using multiple approaches to explore the consequences of future pCO2 levels on organisms.

Net primary productivity, POC export, Th234 and U238 activities and abundance of autotrophs during U.S.C.G.C. Healy cruises HLY0802 and HLY0803

Seasonal patterns in the partitioning of phytoplankton carbon during receding sea ice conditions in the eastern Bering Sea water column are presented using rates of 14C net primary productivity (NPP), phototrophic plankton carbon content, and POC export fluxes from shelf and slope waters in the spring (March 30-May 6) and summer (July 3-30) of 2008. At ice-covered and marginal ice zone (MIZ) stations on the inner and middle shelf in spring, NPP averaged 76 ± 93 mmol C/m**2/d, and in ice-free waters on the outer shelf NPP averaged 102 ± 137 mmol C/m**2/d. In summer, rates of NPP were more uniform across the entire shelf and averaged 43 ± 23 mmol C/m**2/d over the entire shelf. A concomitant shift was observed in the phototrophic pico-, nano-, and microplankton community in the chlorophyll maximum, from a diatom dominated system (80 ± 12% autotrophic C) in ice covered and MIZ waters in spring, to a microflagellate dominated system (71 ± 31% autotrophic C) in summer. Sediment trap POC fluxes near the 1% PAR depth in ice-free slope waters increased by 70% from spring to summer, from 10 ± 7 mmol C/m**2/d to 17 ± 5 mmol C/m**2/d, respectively. Over the shelf, under-ice trap fluxes at 20 m were higher, averaging 43 ± 17 mmol C/m**2/d POC export over the shelf and slope estimated from 234Th deficits averaged 11 ± 5 mmol C/m**2/d in spring and 10 ± 2 mmol C/m**2/d in summer. Average e-ratios calculated on a station-by-station basis decreased by ~ 30% from spring to summer, from 0.46 ± 0.48 in ice-covered and MIZ waters, to 0.33 ± 0.26 in summer, though the high uncertainty prevents a statistical differentiation of these data.

Characterization of late Campanian and Maastrichtian planktonic foraminiferal depth habitats and vital activities based on stable isotopes

Depth habitats of 56 late Cretaceous planktonic foraminiferal species from cool and warm climate modes were determined based on stable isotope analyses of deep-sea samples from the equatorial Pacific DSDP Sites 577A and 463, and South Atlantic DSDP Site 525A. The following conclusions can be reached: Planoglobulina multicamerata (De Klasz) and Heterohelix rajagopalani (Govindan) occupied the deepest plankton habitats, followed by Abathomphalus mayaroensis (Bolli), Globotruncanella havanensis (Voorwijk), Gublerina cuvillieri Kikoine, and Laeviheterohelix glabrans (Cushman) also at subthermocline depth. Most keeled globotruncanids, and possibly Globigerinelliodes and Racemiguembelina species, lived at or within the thermocline layer. Heterohelix globulosa (Ehrenberg) and Rugoglobigerina, Pseudotextularia and Planoglobulina occupied the subsurface depth of the mixed layer, and Pseudoguembelina species inhabited the surface mixed layer. However, depth ranking of some species varied depending on warm or cool climate modes, and late Campanian or Maastrichtian age. For example, most keeled globotruncanids occupied similar shallow subsurface habitats as Rugoglobigerina during the warm late Campanian, but occupied the deeper thermocline layer during cool climatic intervals. Two distinct types of "vital effect" mechanisms reflecting photosymbiosis and respiration effects can be recognized by the exceptional delta13C signals of some species. (1) Photosymbiosis is implied by the repetitive pattern of relatively enriched delta13C values of Racemiguembelina (strongest), Planoglobulina, Rosita and Rugoglobigerina species, Pseudoguembelina excolata (weakest). (2) Enriched respiration 12C products are recognized in A. mayaroensis, Gublerina acuta De Klasz, and Heterohelix planata (Cushman). Isotopic trends between samples suggest that photosymbiotic activities varied between localities or during different climate modes, and may have ceased under certain environmental conditions. The appearance of most photosymbiotic species in the late Maastrichtian suggests oligotrophic conditions associated with increased water-mass stratification.

Physical, biological and chemical characteristics of Canadian and Danish lakes during summer

1. Winter temperatures differ markedly on the Canadian prairies compared with Denmark. Between 1 January 1998 and 31 December 2002, average weekly and monthly temperatures did not drop below 0 °C in the vicinity of Silkeborg, Denmark. Over this same time, weekly average temperatures near Calgary, Alberta, Canada, often dropped below -10 °C for 3-5 weeks and the average monthly temperature was below 0 °C for 2-4 months. Accordingly, winter ice conditions in shallow lakes in Canada and Denmark differed considerably. 2. To assess the implications of winter climate for lake biotic structure and function we compared a number of variables that describe the chemistry and biology of shallow Canadian and Danish lakes that had been chosen to have similar morphometries. 3. The Danish lakes had a fourfold higher ratio of chlorophyll-a: total phosphorus (TP). Zooplankton : phytoplankton carbon was related to TP and fish abundance in Danish lakes but not in Canadian lakes. There was no significant difference in the ratio log total zooplankton biomass : log TP and the Canadian lakes had a significantly higher proportion of cladocerans that were Daphnia. These differences correspond well with the fact that the Danish lakes have more abundant and diverse fish communities than the Canadian lakes. 4. Our results suggest that severe Canadian winters lead to anoxia under ice and more depauperate fish communities, and stronger zooplankton control on phytoplankton in shallow prairie lakes compared with shallow Danish lakes. If climate change leads to warmer winters and a shorter duration of ice cover, we predict that shallow Canadian prairie lakes will experience increased survivorship of planktivores and stronger control of zooplankton. This, in turn, might decrease zooplankton control on phytoplankton, leading to 'greener' lakes on the Canadian prairies.

Results of biological and geological bottom investigations carried out during Cruise 43 of R/V Akademik Kurchatov in the South Atlantic

The book is devoted to investigations of benthic fauna and geology of the Southern Atlantic Ocean. These works have been carried out in terms of exploring biological structure of the ocean and are of great importance for development of this fundamental problem. They are based on material collected during Cruise 43 of R/V Akademik Kurchatov in 1985-1986 and Cruise 43 of R/V Dmitry Mendeleev in 1989. Problems of quantitative distribution, group composition and trophic structure of benthos in the Southern Scotia Sea, along the east-west Transatlantic section along 31°30'S, and offshore Namibia in the area of the Benguela upwelling are under consideration in the book. Authors present new data on fauna of several groups of deep-sea bottom animals and their zoogeography. Much attention is paid to analysis of morphological structure of the Scotia Sea floor considered in terms of plate tectonics. Bottom sediments along the Transatlantic section and facial variation of sediments in the area of South Shetland Islands and of the continental margin of Namibia are under consideration.

Physiological and biochemical characteristics of Calanoides carinatus in waters off the coast of Namibia

Biochemical composition, feeding and oxygen uptake rate of mass planktic copepod Calanoides carinatus were studied off the coast of Namibia in January 1986. Population of this species in the area had two parts: the surface group inhabiting the 0-100 m layer and the deep part inhabiting depths greater than 200 m. Individuals in the surface and deep parts of the population differed in food content of guts, lipid content of bodies, oxygen uptake rate and behavior. Differences in biochemical composition and rate of physiological processes indicate that individuals in the deep part of the population are in diapause. Nature of changes in biochemical composition of C. carinatus in surface and deep waters in relation to life cycle characteristics in upwelling waters are discussed.

Biological and chemical oceanographic profiles from the equatorial Atlantic

The volume presents planktological and chemical data collected during cruise No. 51 of RV "Meteor" to the equatorial Atlantic (FGGE '79) from February to June 1979. A standard section along the meridian 22° W across the equator was sampled ten times between 2° S and 3° N. Together with a temperature and salinity profile, concentrations of oxygen, nutrients and chlorophyll a were analyzed in water samples down to a depth of 250 m. Solar radiation and light depths were measured for determination of primary productivity of the euphotic zone according to the simulated in situ method. Zooplankton biomass was estimated in 5 depth intervals down to 300 m by means of a multiple opening and closing net equipped with a mesh size of 100 µm.

Effects of pCO2 and iron on the elemental composition and cell geometry of the marine diatom Pseudo-nitzschia pseudodelicatissima//(Bacillariophyceae)

Partial pressure of CO2 (pCO2) and iron availability in seawater show corresponding changes due to biological and anthropogenic activities. The simultaneous change in these factors precludes an understanding of their independent effects on the ecophysiology of phytoplankton. In addition, there is a lack of data regarding the interactive effects of these factors on phytoplankton cellular stoichiometry, which is a key driving factor for the biogeochemical cycling of oceanic nutrients. Here, we investigated the effects of pCO2 and iron availability on the elemental composition (C, N, P, and Si) of the diatom Pseudo-nitzschia pseudodelicatissima (Hasle) Hasle by dilute batch cultures under 4 pCO2 (~200, ~380, ~600, and ~800 µatm) and five dissolved inorganic iron (Fe'; ~5, ~10, ~20, ~50, and ~100 pmol /L) conditions. Our experimental procedure successfully overcame the problems associated with simultaneous changes in pCO2 and Fe' by independently manipulating carbonate chemistry and iron speciation, which allowed us to evaluate the individual effects of pCO2 and iron availability. We found that the C:N ratio decreased significantly only with an increase in Fe', whereas the C:P ratio increased significantly only with an increase in pCO2. Both Si:C and Si:N ratios decreased with increasing pCO2 and Fe'. Our results indicate that changes in pCO2 and iron availability could influence the biogeochemical cycling of nutrients in future oceans with high- CO2 levels, and, similarly, during the time course of phytoplankton blooms. Moreover, pCO2 and iron availability may also have affected oceanic nutrient biogeochemistry in the past, as these conditions have changed markedly over the Earth's history.