Phosphates and silicates in sea ice of the high-latitudinal Arctic: Data of the North Pole-34 drifting ice station

The dynamics of phosphates and silicates in sea ice of the high-latitudinal Arctic are considered for the period from November 2005 to May 2006. It is shown that, during the ice formation, silicates are included into it in the same ratio to the salinity that is characteristic of the under-ice water. The further dynamics of silicates are determined by their bioassimilation with the beginning of the polar day and by the biogenic silicon accumulation at the bottom meltwater pools with subsequent leaching. Phosphates are included into ice in a ratio higher than that occurring in the under-ice water. This is caused by the fact that the liquid phase of sea ice represents the composition of the surface microlayer (SML) at the ice-water interface, which is enriched in organic matter and in the products of its destruction (particularly, in phosphates). With the onset of the polar day, the content of phosphates first markedly increases (due to the photo oxidation of biogenic organic matter) and then decreases because of bioassimilation. At the beginning of the polar day, the primary production of diatoms was estimated to be ～0.3 mg C/m² day.     

Effects of CO<Subscript>2</Subscript> on Marine Fish: Larvae and Adults

CO₂-enriched seawater was far more toxic to eggs and larvae of a marine fish, silver seabream, Pagrus major, than HCl-acidified seawater when tested at the same seawater pH. Data on the effects of acidified seawater can therefore not be used to estimate the toxicity of CO₂, as has been done in earlier studies. Ontogenetic changes in CO₂ tolerance of two marine bony fishes (Pag. major and Japanese sillago, Sillago japonica) showed a similar, characteristic pattern: the cleavage and juvenile stages were most susceptible, whereas the preflexion and flexion stages were much more tolerant to CO₂. Adult Japanese amberjack, Seriola quinqueradiata, and bastard halibut, Paralichthys olivaceus, died within 8 and 48 h, respectively, during exposure to seawater equilibrated with 5% CO₂. Only 20% of a cartilaginous fish, starspotted smooth-hound, Mustelus manazo, died at 7% CO₂ within 72 h. Arterial pH initially decreased but completely recovered within 1-24 h for Ser. quinqueradiata and Par. olivaceus at 1 and 3% CO₂, but the recovery was slower and complete only at 1% for M. manazo. During exposure to 5% CO₂, Par. olivaceus died after arterial pH had been completely restored. Exposure to 5% CO₂ rapidly depressed the cardiac output of Ser. quinqueradiata, while 1% CO₂ had no effect. Both levels of ambient CO₂ had no effect on blood O₂ levels. We tentatively conclude that cardiac failure is important in the mechanisms by which CO₂ kills fish. High CO₂ levels near injection points during CO₂ ocean sequestration are likely to have acute deleterious effects on both larvae and adults of marine fishes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Features of coastal upwelling regions that determine net air-sea CO<Subscript>2</Subscript> flux

The influence of the coastal ocean on global net annual air-sea CO₂ fluxes remains uncertain. However, it is well known that air-sea pCO₂ disequilibria can be large (ocean pCO₂ ranging from ∼400 μatm above atmospheric saturation to ∼250 μatm below) in eastern boundary currents, and it has been hypothesized that these regions may be an appreciable net carbon sink. In addition it has been shown that the high productivity in these regions (responsible for the exceptionally low surface pCO₂) can cause nutrients and inorganic carbon to become more concentrated in the lower layer of the water column over the shelf relative to adjacent open ocean waters of the same density. This paper explores the potential role of the winter season in determining the net annual CO₂ flux in temperate zone eastern boundary currents, using the results from a box model. The model is parameterized and forced to represent the northernmost part of the upwelling region on the North American Pacific coast. Model results are compared to the few summer data that exist in that region. The model is also used to determine the effect that upwelling and downwelling strength have on the net annual CO₂ flux. Results show that downwelling may play an important role in limiting the amount of CO₂ outgassing that occurs during winter. Finally data from three distinct regions on the Pacific coast are compared to highlight the importance of upwelling and downwelling strength in determining carbon fluxes in eastern boundary currents and to suggest that other features, such as shelf width, are likely to be important.     

Spatial structure of the <Emphasis Type="Italic">M</Emphasis><Subscript>2</Subscript> tidal wave in the canadian arctic archipelago

The surface M ₂ tide in the Canadian Arctic Archipelago (CAA) is reproduced on the basis of the QUODDY-4 three-dimensional finite-element hydrodynamic model. Particular emphasis has been placed on comparing model estimates for the amplitudes and phases of tidal elevations and the parameters of ellipses (major semiaxis and eccentricity) of the barotropic tidal current velocity with observational data. We present their spatial distributions and the distributions of averaged (over a tidal cycle) values of the density, horizontal transfer, and dissipation rate of barotropic tidal energy. It is found that the CAA is a much less effective dissipator of barotropic tidal energy than the World Ocean.     

Effects of seawater acidification by ocean CO<Subscript>2</Subscript> sequestration on bathypelagic prokaryote activities

We investigated the effects of seawater acidification induced by ocean CO₂ sequestration on bathypelagic prokaryotes. We simulated acidification conditions by bubbling high-CO₂ air or adding chemical buffer solutions to seawater samples in order to examine changes in total cell counts, heterotrophic production rate, direct viable cell count, and relative abundance of Bacteria and Archaea. Considerable suppression of prokaryotic activities was observed at pH 7.0 or lower, especially in samples enriched with organic matter. The relative abundance of Archaea increased with increasing CO₂ concentration. We found that seawater acidification can potentially alter heterotrophic activities and community structure of bathypelagic prokaryotes.     

CO<Subscript>2</Subscript> Flux Measurements over the Sea Surface by Eddy Correlation and Aerodynamic Techniques

The measurements of the vertical transport of CO₂ were carried out over the Sea of Japan using the specially designed pier of Kyoto University on September 20 to 22, 2000. CO₂ fluxes were measured by the eddy correlation and aerodynamic techniques. Both techniques showed comparable CO₂ fluxes during sea breeze conditions: −0.001 to −0.08 mg m⁻²s⁻¹ with the mean of −0.05 mg m⁻²s⁻¹. This means that the measuring site satisfies the fetch requirement for meteorological observations under sea breeze conditions. Moreover, the eddy diffusivity coefficient used in the aerodynamic technique is found to be consistent with the coefficient used in the eddy correlation technique. The present result leads us to conclude that the aerodynamic technique may be applicable to underway CO₂ flux measurements over the ocean and may be used in place of the bulk technique. The important point is the need to maintain a measuring accuracy of CO₂ concentration difference of the order of 0.1 ppmv on the research vessels or the buoys.     

Uptake mechanism of anthropogenic CO<Subscript>2</Subscript> in the Kuroshio Extension region in an ocean general circulation model

The uptake mechanism of anthropogenic CO₂ in the Kuroshio Extension is examined by a Lagrangian approach using a biogeochemical model embedded in an ocean general circulation model. It is found that the uptake of anthropogenic CO₂ is caused mainly by the increase of pCO₂ dependency of seawater on temperature, which is caused by greater dissolved inorganic carbon concentration in the modern state than in the pre-industrial state. In contrast with the view of previous studies, the effect of the vertical entrainment, which brings waters that last contacted the atmosphere with the past lower CO₂ concentration, is comparatively small. Winter uptake of anthropogenic CO₂ increases with the rise of the atmospheric CO₂ level, while summer uptake is relatively stable, resulting in a larger seasonal cycle of the uptake. This increase is significant, especially in the Kuroshio Extension region. It is newly suggested that this increase in the Kuroshio Extension region is largely caused by the combined effects of the increased pCO₂ dependency of the sea water on the temperature and the seasonal difference in cooling.     

Air-sea CO<Subscript>2</Subscript> flux by eddy covariance technique in the equatorial Indian Ocean

Direct measurements of the air-sea CO₂ flux by the eddy covariance technique were carried out in the equatorial Indian Ocean. The turbulent flux observation system was installed at the top of the foremast of the R/V MIRAI, thus minimizing dynamical and thermal effects of the ship body. During the turbulent flux runs around the two stations, the vessel was steered into the wind at constant speed. The power spectra of the temperature or water vapor density fluctuations followed the Kolmogorov −5/3 power law, although that of the CO₂ density fluctuation showed white noise in the high frequency range. However, the cospectrum of the vertical wind velocity and CO₂ density was well matched with those of the vertical velocity and temperature or water vapor density in this frequency range, and the CO₂ white noise did not influence the CO₂ flux. The raw CO₂ fluxes due to the turbulent transport showed a sink from the air to the ocean, and had almost the same value as the source CO₂ fluxes due to the mean vertical flow, corrected by the sensible and latent heat fluxes (called the Webb correction). The total CO₂ fluxes including the Webb correction terms showed a source from the ocean to the air, and were larger than the bulk CO₂ fluxes estimated using the gas transfer velocity by mass balance techniques.     

The spatial distribution of surface <Emphasis Type="Italic">f</Emphasis>CO<Subscript>2</Subscript> in the Southwestern East Sea/Japan sea during summer 2005

Fugacity of CO₂ (fCO₂), temperature, salinity, nutrients, and chlorophyll-a were measured in the surface waters of southwestern East Sea/Japan Sea in July 2005. Surface waters were divided into three waters based on hydrographic characteristics: the water with moderate sea surface temperature (SST) and high sea surface salinity (SSS) located east of the front (East water); the water with high SST and moderate SSS located west of the front (West water); and the water with low SST and SSS located in the middle part of the study area (Middle water). High fCO₂ larger than 420 μatm were found in the West water. In the Middle water, CO₂ was undersaturated with respect to the atmosphere, with values between 246 and 380 μatm. Moderate fCO₂ values ranging from 370 to 420 μatm were observed in the East water. For the East and West waters, estimates of temperature dependency of fCO₂ (12.6 and 15.1 μatm °C⁻¹, respectively) were rather similar to a theoretical value, indicating that SST is likely to be a major factor controlling the surface fCO₂ distribution in these two regions. In the Middle water, however, the estimated temperature dependence was somewhat lower than the theoretical value, and relatively high concentrations of surface chlorophyll-a coincided with the low surface fCO₂, implying that biological uptake may considerably affect the fCO₂ distribution. The net sea-to-air CO₂ flux of the study area was estimated to be 0.30±4.81 mmol m⁻² day⁻¹ in summer, 2005.     

Biological Impact of Elevated Ocean CO<Subscript>2</Subscript> Concentrations: Lessons from Animal Physiology and Earth History

CO₂ currently accumulating in the atmosphere permeates into ocean surface layers, where it may impact on marine animals in addition to effects caused by global warming. At the same time, several countries are developing scenarios for the disposal of anthropogenic CO₂ in the worlds' oceans, especially the deep sea. Elevated CO₂ partial pressures (hypercapnia) will affect the physiology of water breathing animals, a phenomenon also considered in recent discussions of a role for CO₂ in mass extinction events in earth history. Our current knowledge of CO₂ effects ranges from effects of hypercapnia on acid-base regulation, calcification and growth to influences on respiration, energy turnover and mode of metabolism. The present paper attempts to evaluate critical processes and the thresholds beyond which these effects may become detrimental. CO₂ elicits acidosis not only in the water, but also in tissues and body fluids. Despite compensatory accumulation of bicarbonate, acid-base parameters (pH, bicarbonate and CO₂ levels) and ion levels reach new steady-state values, with specific, long-term effects on metabolic functions. Even though such processes may not be detrimental, they are expected to affect long-term growth and reproduction and may thus be harmful at population and species levels. Sensitivity is maximal in ommastrephid squid, which are characterized by a high metabolic rate and extremely pH-sensitive blood oxygen transport. Acute sensitivity is interpreted to be less in fish with intracellular blood pigments and higher capacities to compensate for CO₂ induced acid-base disturbances than invertebrates. Virtually nothing is known about the degree to which deep-sea fishes are affected by short or long term hypercapnia. Sensitivity to CO₂ is hypothesized to be related to the organizational level of an animal, its energy requirements and mode of life. Long-term effects expected at population and species levels are in line with recent considerations of a detrimental role of CO₂ during mass extinctions in the earth's history. Future research is needed in this area to evaluate critical effects of the various CO₂ disposal scenarios. This revised version was published online in July 2006 with corrections to the Cover Date.     

Physiological Responses of the Mediterranean Subtidal Alga <Emphasis Type="Italic">Peyssonnelia squamaria</Emphasis> to Elevated CO<Subscript>2</Subscript>

The ecological consequences of ocean acidification are unclear due to varying physiological properties of macroalgae and species-specific responses. Therefore, in the present study, we used a laboratory culture experiment to analyse the eco-physiological responses of the Mediterranean subtidal red alga Peyssonnelia squamaria to CO₂-induced lower pH. Our results showed an increase in the photosynthetic performance and growth rate of P. squamaria, despite the reduction in CaCO₃ content in the low pH treatment. According to our results, we believe that samples exposed to elevated CO₂ could be regulated own nitrogen metabolism to support increased growth rate and it may be down-regulated nitrate uptake. As a result, we hypothesize that P. squamaria may benefit from ocean acidification.     

Ventilation time and anthropogenic CO<Subscript>2</Subscript> in the Bering Sea and the Arctic Ocean based on carbon tetrachloride measurements

The Arctic Ocean is connected to the Pacific by the Bering Sea and the Bering Strait. During the 4th Chinese National Arctic Research Expedition, measurements of carbon tetrachloride (CCl₄) were used to estimate ventilation time-scales and anthropogenic CO₂ (C_ant) concentrations in the Arctic Ocean and Bering Sea based on the transit time distribution method. The profile distribution showed that there was a high-CCl₄ tongue entering through the Canada Basin in the intermediate layer (27.6?<?σ_θ?<?28), at latitudes between 78 and 85°N, which may be related to the inflow of Atlantic water. Between stations B09 and B10, upwelling appeared to occur near the continental slope in the Bering Sea. The ventilation time scales (mean ages) for deep and bottom water in the Arctic Ocean (~?230–380 years) were shorter than in the Bering Sea (~?430–970 years). Higher mean ages show that ventilation processes are weaker in the intermediate water of the Bering Sea than in the Arctic Ocean. The mean C_ant column inventory in the upper 4000 m was higher (60–82 mol m^?2) in the Arctic Ocean compared to the Bering Sea (35–48 mol m^?2).     

Latitudinal dependence of variations in stratospheric NO<Subscript>2</Subscript> content

Diurnal and annual variations in the NO₂ total content (TC), the effect of its decrease owing to the products of the eruption of Mt. Pinatubo, its variations during an 11-year cycle of solar activity, and its linear trends are analyzed on the basis of data obtained from the ground-based spectrometric measurements of the NO₂ TC in stratospheric vertical columns over the stations of the Network for the Detection of Atmospheric Composition Change. Latitudinal dependence of the indicated variations and trends is revealed. The annual estimates of the linear trends of the NO₂ TC are found to be mostly positive for the middle and low latitudes of the Southern Hemisphere and negative for the middle and low latitudes of the Northern Hemisphere. The maximum values of the positive and negative trends amount to ～10% per ten years. In the high and polar latitudes of both hemispheres, the annual trend estimates are statistically insignificant. Seasonal estimates of the trends may differ from their annual estimates. The trends and solar-activity effect in the NO₂ TC, which were estimated by using the two-dimensional model SOCRATES, as well as the analytical estimates of a zonal mean trend of the NO₂ TC, on the whole, significantly differ from the estimates obtained from the measurements.     

Retrieval of total ozone in the mesosphere with a new model of electronic-vibrational kinetics of O<Subscript>3</Subscript> and O<Subscript>2</Subscript> photolysis products

The paper presents a new model of electronic-vibrational kinetics of the products of ozone and molecular oxygen photodissociation in the terrestrial middle atmosphere. The model includes 45 excited states of the oxygen molecules O₂(b ¹, Σ _g ⁺ ,v= 0−2), O₂ (a ¹Δ _g , v= 0−5), and O₂(X ³Σ _g ⁻ , v= 1−35) and of the metastable atom O (¹ D) and over 100 aeronomic reactions. The model takes into account the dependence of quantum yields of the production of O₂(a ¹Δ _g , v= 0−5) in a singlet channel of ozone photolysis in the Hartley band on the wavelength of photolytic emission. Taking account of the electronic-vibrational kinetics is important in retrieval of the vertical profiles of ozone concentration from measured intensities of the Atm and IR Atm emissions of the oxygen bands above 65 km and leads to an increase in the ozone concentration retrieved from the 1.27-μm emission, in contrast to the previous model of pure electronic kinetics. Sensitivity analysis of the new model is made for variations in the concentrations of atmospheric constituents ([O₂], [N₂], [O(³P)], [O₃], [CO₂]), the gas temperature, rate constants of the reactions, and quantum yields of the reaction products. A group of reactions that most strongly affect the uncertainty of ozone retrieval from measured intensities of atmospheric emissions of molecular oxygen O₂(b ¹Σ _g ⁺ , v) and O₂(a ¹Δ _g , v) has been determined. Original Russian Text ? V.A. Yankovsky, V.A. Kuleshov, R.O. Manuilova, A.O. Semenov, 2007, published in Izvestiya AN. Fizika Atmosfery i Okeana, 2007, Vol. 43, No. 4, pp. 557–569.     

Recent increase in surface fCO<Subscript>2</Subscript> in the western subtropical North Pacific

We observed unusually high levels (> 440 μatm) of carbon dioxide fugacity (fCO₂) in surface seawater in the western subtropical North Pacific, the area where Subtropical Mode Water is formed, during summer 2015. The NOAA Kuroshio Extension Observatory moored buoy located in this region also measured high CO₂ values, up to 500 μatm during this period. These high sea surface fCO₂ (fCO_2SW) values are explained by much higher normalized total dissolved inorganic carbon and slightly higher normalized total alkalinity concentrations in this region compared to the equatorial Pacific. Moreover, these values are much higher than the climatological CO₂ values, even considering increasing atmospheric CO₂, indicating a recent large increase in sea surface CO₂ concentrations. A large seasonal change in sea surface temperature contributed to higher surface fCO_2SW in the summer of 2015.     

Seasonal variability of surface and internal M<Subscript>2</Subscript> tides in the Arctic Ocean

The modeling results of surface and internal M₂ tides for summer and winter periods in the Arctic Ocean (AO) are presented. We employed a modified version of the three-dimensional finite-element hydrothermodynamic model QUODDY-4 differing from the original model by using a rotated (instead of spherical) coordinate system and by considering the equilibrium-tide effects. It has been shown that the modeling results for the surface tide differs little from the results obtained earlier by other authors. According to these results, the amplitudes of internal tidal waves (ITWs) in the AO are significantly lower than in other oceans and the ITWs proper have the character of trapped waves. Their source of generation is located at the continental slope northwest of the New Siberian Islands. Our results are consistent with the fields of average (over a tidal cycle) and integral (by depth) densities of baroclinic tidal energy, the maximum baroclinic tidal velocity, and the coefficient of diapycnic mixing. The local rate of baroclinic tidal energy dissipation at the AO ridges increases as it approaches the bottom, as was observed on Mid-Atlantic and Hawaii ridges (but merely within the bottom boundary layer) and is two to three orders of magnitude lower than in other oceans. The ITW degeneration scale in the AO is several hundreds of kilometers in summer and winter, remaining within the range of its values between 100 and 1000 km in mid- and low-latitude oceans. In both seasons, the integral (over the AO area) rate of baroclinic tidal energy dissipation is two orders of magnitude lower than the global estimate (2.5 × 10¹² W).     

The influence of the spatial heterogeneity of vegetation cover and surface topography on vertical CO<Subscript>2</Subscript> fluxes within the atmospheric surface layer

The influence of the spatial heterogeneity of vegetation cover and topography on CO₂ fluxes in the atmospheric surface layer is estimated using a two-dimensional (2D) hydrodynamic model of turbulent exchange. A ~4.5-km-long profile that crossed a hilly area with a mosaic vegetation cover in Tula region was selected for model experiments. During the first experiment, a wind field and vertical fluxes were calculated by the 2D model for the entire selected profile with respect to the horizontal heterogeneity of the vegetation cover and surface topography. In the second experiment, the profile was considered an assemblage of elementary independent homogeneous segments; for each of them, vertical fluxes were calculated by the 2D model with the assumption of ‘zero’ horizontal advection, i.e., the required functions are independent of the horizontal coordinates. The influences of any boundary effects that appear at the interface between the different vegetation communities and at topographical irregularities on the turbulent regime are ignored in this case. For the profile selected, ignoring the horizontal advection, disturbances in the wind field that appeared at surface topography irregularities, and boundaries between different vegetation communities can lead to a 26% underestimation of the total CО₂ absorption by the ground surface on a clear sunny day under summer weather conditions.     

The Interactive Effects of Elevated CO<Subscript>2</Subscript> and Ammonium Enrichment on the Physiological Performances of <Emphasis Type="Italic">Saccharina japonica</Emphasis> (Laminariales,Phaeophyta)

Environmental challenges such as ocean acidification and eutrophication influence the physiology of kelp species. We investigated their interactive effects on Saccharina japonica (Laminariales, Phaeophyta) under two pH conditions [Low, 7.50; High (control), 8.10] and three NH ₄ ⁺ concentrations (Low, 4; Medium, 60; High, 120 μM). The degree of variation of pH values in the culture medium and inhibition rate of photosynthetic oxygen evolution by acetazolamide were affected by pH treatments. Relative growth rates, carbon, nitrogen, and the C:N ratio in tissue samples were influenced by higher concentrations of NH ₄ ⁺ . Rates of photosynthetic oxygen evolution were enhanced under elevated CO₂ or NH ₄ ⁺ conditions, independently, but these two factors did not show an interactive effect. However, rates of NH ₄ ⁺ uptake were influenced by the interactive effect of increased CO₂ under elevated NH ₄ ⁺ treatment. Although ocean acidification and eutrophication states had an impact on physiological performance, chlorophyll fluorescence was not affected by those conditions. Our results indicated that the physiological reactions by this alga were influenced to some extent by a rise in the levels of CO₂ and NH ₄ ⁺ . Therefore, we expect that the biomass accumulation of S. japonica may well increase under future scenarios of ocean acidification and eutrophication.     

Analysis of satellite observations of the tropospheric NO<Subscript>2</Subscript> content over the Moscow region

The tropospheric NO₂ content over the Moscow region is analyzed on the basis of data of the satellite Ozone Monitoring Instrument (OMI) in the period 2004–2009. The spatial distributions of NO₂ are presented, and some of their features are interpreted. The characteristics of the seasonal and weekly cycles of NO₂ are described, as are its interannual and long-term variations. The relationship between the variabilities of the NO₂ content and the aerological parameters is investigated on different time scales. The mutual influence of regional pollution and meteorological regimes is discussed. The seasonal and weekly NO₂ cycles over Moscow are compared with those over the largest worldwide agglomerations.