Structure of plankton phytocoenoses in the shelf waters of the northeastern Black Sea during the <Emphasis Type="Italic">Emiliania huxleyi</Emphasis> bloom in 2002–2005

It is shown that, in 2002–2005, the mass development of the coccolithofore Emiliania huxleyi on the Gelendzhik shelf occurred annually and in May–June its abundance reached 1.5 × 10⁶ cells/l. In 2004–2005, the bloom of E. huxleyi was accompanied by a mass development of the diatom alga Chaetoceros subtilis var. abnormis f. simplex (0.6–0.9 × 10⁶ cells/l); for the first time, it was registered as a dominating form of the Black Sea phytoplankton. Small flagellates and picoplankton algae played a noticeable role in the phytoplankton throughout the entire period of the studies. Meanwhile, in the early summer period, the bulk of the biomass consisted of coccolithophores (50–60%), while, in the late summer period, diatomaceous algae dominated (50–70%). Among the ecological factors that favor the coccolithophore development one may note the microstratification of the upper mixed layer at a high illumination level and high temperature in the surface waters (18–21°C). The terrigenous runoff during the rainy period had a negative effect on the E. huxleyi development, while storms dispersed the population over the upper mixed layer. The wind-induced near-shore upwelling stimulated the development of diatoms.     

Potential for heavy metal (copper and zinc) removal from contaminated marine sediments using microalgae and light emitting diodes

The effects of monochromatic (blue, yellow and red LED) and mixed wavelengths (fluorescent lamp) on the adsorption and absorption of Cu and Zn by Phaeodactylum tricornutum, Nitzschia sp., Skeletonema sp., and Chlorella vulgaris were investigated. In addition, we confirmed the potential of microalgae for phytoremediation of these heavy metals from contaminated marine sediment by using microcosm experiments that incorporated LEDs and semipermeable membrane (SPM) tube containing microalgae. Among the four microalgae, C. vulgaris grown under red LED exhibited the highest Cu and Zn removal with values of 17.5 × 10^-15 g Cu/cell and 38.3 × 10^-15 g Zn/cell, respectively. Thus, C. vulgaris could be a useful species for phytoremediation. In the microcosm experiments with SPM containing C. vulgaris, the highest Cu and Zn removal from sediment and interstitial water showed under red LED. Therefore, phytoremediation using LED and SPM tube containing microalgae could be utilized as an eco-friendly technique for remediating contaminated marine sediment.     

Effect of Mercury Chloride on the Chlorophyl <Emphasis Type="Italic">a</Emphasis> and Pheophytin Content in Marine Microalgae: Measuring the Flow of Autotrophic Phytoplankton Using Sediment Traps Data

The present work aimed to study the influence of mercuric chloride (HgCl₂) on pigment content (chlorophyll a and pheophytin) in sediment traps on the basis of experimental data. The marine microalgal cultures of Conticribra weissflogii (Mediophyceae), Tetraselmis viridis (Chlorodendrophyceae), Amphidinium carterae (Dinophyceae), Nannochloropsis sp. (Eustigmatophyceae) were used. The obtained results revealed that the influence of mercury on pigment content as well as on photosynthetic activity was different in different species. The considerable decrease in phytopigments content was observed in Amphidinium carterae and Conticribra weissflogii, while the proportion of pheophytin increased. The pigment content of Tetraselmis viridis was not different from the control line, while for Nannochloropsis sp. the increase in pigment concentration was noticed. The complete immediate inhibition of photosynthetic activity was observed in Conticribra weissflogii, Tetraselmis viridis, Amphidinium carterae, while Nannochloropsis sp. responded only after 24 h of exposition. The pigment degradation rate was almost the same for diatoms and dinoflagellates. The equation for estimating the phytopigments content in sediment traps, that takes into consideration the exposition time, is proposed.     

Features of the spatial distribution of phytoplankton in Nhatrang Bay of the South China Sea during the rainy season

The species composition, phytoplankton abundance, and relative yield of the variable fluorescence (F _v /F _m ) were determined in the mesotrophic Nhatrang Bay in October–November of 2004. The species diversity (250 taxonomic units) and heterogeneity of the phytoplankton structure were high. With respect to the number of species and their abundance, diatoms prevailed. In selected parts of the bay, dinoflagellates dominated. The mean biomass in the water column under 1 m² (B _t ) varied from 2.3 to 64.4 mg C/m³ being 31.0 mg C/m³ on average. The values of B _t were the lowest at the stations nearest to the river mouth. Seaward, B _t increased. The values of B _t increased with depth at some stations and decreased at others. In the surface sea layers, the biomass was lower than that in the underlying waters. The values of F _v /F _m ranged from 0.10 to 0.64 (at a mean value of 0.49). The lowest values of F _v /F _m were observed in the area close to the seaport. Over the greater part of the bay, the values of F _v /F _m were higher than 0.47. Such values are indicative of the relatively high potential photosynthetic activity of the phytoplankton. The abundance and species diversity were higher than those in the dry season (March–April).     

Spatial Distribution and Seasonal Dynamics of the Chlorophyll <Emphasis Type="Italic">a</Emphasis> Concentration in the Sea of Azov Based on MERIS Images

The chlorophyll a concentration (Cchl a) in the Sea of Azov is estimated by the two-band NIR-red algorithm [34] from MERIS images for 2002–2012. The sea-truth spectrophotometric measurements and MERIS remote estimates of Cchl a are compared. The monthly average Cchl a values are mapped from MERIS data for its lifetime for the first time. The features of the spatiotemporal distribution of Cchl a are ascertained. Differences between the seasonal dynamics of Cchl a in the Sea of Azov according to the literature data and the dynamics derived from MERIS data are found, namely: the summer–autumn phytoplankton growth period is longer than the spring period and is characterized by higher Cchl a values throughout the water area.     

Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific

Intensive observations using hydrographical cruises and moored sediment trap deployments during 2010 and 2012 at station K2 in the North Pacific Western Subarctic Gyre (WSG) revealed seasonal changes in δ ¹⁵N of both suspended and settling particles. Suspended particles (SUS) were collected from depths between the surface and 200 m; settling particles by drifting sediment traps (DST; 100–200 m) and moored sediment traps (MST; 200 and 500 m). All particles showed higher δ ¹⁵N values in winter and lower in summer, contrary to the expected by isotopic fractionation during phytoplankton nitrate consumption. We suggest that these observed isotopic patterns are due to ammonium consumption via light-controlled nitrification, which could induce variations in δ ¹⁵N(SUS) of 0.4–3.1 ‰ in the euphotic zone (EZ). The δ ¹⁵N(SUS) signature was reflected by δ ¹⁵N(DST) despite modifications during biogenic transformation from suspended particles in the EZ. δ ¹⁵N enrichment (average: 3.6 ‰) and the increase in C:N ratio (by 1.6) in settling particles suggests year-round contributions of metabolites from herbivorous zooplankton as well as TEPs produced by diatoms. Accordingly, seasonal δ ¹⁵N(DST) variations of 2.4–7.0 ‰ showed a significant correlation with primary productivity (PP) at K2. By applying the observed δ ¹⁵N(DST) vs. PP regression to δ ¹⁵N(MST) of 1.9–8.0 ‰, we constructed the first annual time-series of PP changes in the WSG. This new approach to estimate productivity can be a powerful tool for further understanding of the biological pump in the WSG, even though its validity needs to be examined carefully.     

Age determination and growth rate of <Emphasis Type="Italic">Mactra chinensis</Emphasis> (Bivalvia: Mactridae) by external rings and chondrophore growth bands

Age, growth and mortality of Mactra chinensis were investigated during the period from October 2012 to September 2013 in Busan, South Korea. The monthly variation of the marginal index (MI) of the shell and chondrophore showed that the ring of this species was formed once a year during July. We estimated the age of M. chinensis by reading the external rings on the shell and the growth bands of the chondrophore to compare growth parameters between the two growth characters. The age of this species ranged from 0 to 8 years (shell-based age reading) and from 0 to 10 years (chondrophore-based age reading). Based on external rings and growth bands of chondrophore for the same period, the von Bertalanffy growth functions were expressed by the equation, L _t = 101.53[1-exp {-0.15(t + 0.75)}] and L _t = 90.03[1-exp {-0.20(t + 0.50)}], respectively. The likelihood test showed that there was a significant difference in L _∞ (P < 0.001), K (P < 0.001), to (P < 0.001) estimated from non-linear regression between the two growth characters.     

Features of the atmospheric boundary layer block for three versions of the WAM wind wave model

The estimated characteristics of the atmospheric boundary layer, obtained by the simulation of wind wave fields using three versions of the WAM numerical model are compared with the well-known empirical dependences of drag coefficient C _d on wind speed U ₁₀ and wave age A, as well as with the dependence of dimensionless roughness height z _n on inverse wave age u*/с р. Calculations carried out for several years in the areas of the Pacific and Indian oceans, based on the ERA-interim and CFSR wind reanalyses have shown good agreement between the model and empirical dependences C _d (U ₁₀) and C _d (A). The range of estimated variability for z _n (u*/с _р ) has been found to be significantly less than empirical. It has been also found that estimated values of wind speed U _10W (t) are overestimated from 5 to 10% in all versions of WAM models compared with the input wind reanalysis U _10R (t) at the moments of appearance maximum values of wind U _10R (t). The reasons for the established features of the WAM model and their dependence on the model version are discussed.     

Indices based on silicoflagellate assemblages offer potential for paleo-reconstructions of the main oceanographic zones of the Southern Ocean

This study reports detailed silicoflagellate assemblage composition and annual seasonal flux from sediment traps at four locations along a transect across the Southern Ocean frontal systems. The four traps sampled the central Subantarctic Zone (SAZ, 47°S site), the Subantarctic Front (SAF, 51°S site), the Polar Frontal Zone (54°S site) and the Antarctic Zone (61°S site) across the 140°E longitude. Annual silicoflagellate fluxes to the deep ocean exhibited a similar latitudinal trend to those of diatom fluxes reported in previous work, with maxima in the Antarctic Zone and minima in the Subantarctic Zone. The data suggest that, along with diatoms, silicoflagellates are important contributors to biogenic silica export at all sites, particularly in the Subantarctic Zone. Two main silicoflagellate genera were observed, with Stephanocha sp. (previously known as Distephanus) dominating polar waters and Dictyocha sp. important in sub-polar waters. This is consistent with previous use of the Dictyocha / Stephanocha ratio to infer paleotemperatures and monitor shifts in the position of the Polar Frontal Zone in the sedimentary record. It appears possible to further refine the application of this approach by using the ratio between two Dictyocha species, because Dictyocha aculeata dominated at the Subantarctic Front, while Dictyocha stapedia dominated in the central Subantarctic Front. Given the well-defined environmental affinities of both species, a new SAF silicoflagellate index (SAF-SI) based on this ratio is proposed as a useful diagnostic for SAF and SAZ water mass signatures in the Plio-Pleistocene and Holocene sedimentary record.     

A new formula for saturated water steam pressure within the temperature range −25 to 220°C

Instead of approximation formula ln(E(t)/E(0)) = [(a ? bt)t/(c + T)] commonly used at present for representing dependence of pressure of saturated streams of liquid water E upon temperature we suggested new approximation formula of greater accuracy in the form ln(E(t)/E(0)) = [(A ? Bt + Ct ²)t/T], where t and T are temperature in °C and K respectively. For this formula with parameters A = 19.846, B = 8.97 × 10^?3, C = 1.248 × 10^?5 and E(0) = 6.1121 GPa with ITS-90 temperature scale and for temperature range from 0°C to 110°C relative difference of approximation applying six parameter formula by W. Wagner and A. Pruß 2002, developed for positive temperatures, is less than 0.005%, that is approximately 15 times less than accuracy obtained with the firs formula. Increase of temperature range results in relative difference increasing, but for even temperature range from 0°C to 220°C it does not higher than 0.1%. For negative temperatures relative difference between our formula and a formula of D. M. Murphy and T. Koop, 2005, is less than 0.1% for temperatures higher than ?25°C. This paper also presents values of coefficients for approximation of Goff and Grach formula recommended by IMO. The procedure of finding dew point T _d for known water steam pressure e _n based on our formula adds up to solving an algebraic equation of a third degree, which coefficients are presented in this paper. For simplifying this procedure this paper also includes approximation ratio applying a coefficient A noted above, in the form T _d (e _n ) = \(\frac{{AT_0 }}{{A - \varepsilon }}\) + 0.0866?² + 0.0116?^10/3, where ? = ln(e _n /E(T ₀)). Error of dew point recovery in this ratio is less than 0.005 K within the range from 0 to 50°C.     

Phytoplankton Community Structure in the Polar Front of the Eastern Barents Sea at the End of the Growth Season

Phytoplankton community and its distribution were investigated in the south part of the Polar Front in the eastern Barents Sea in October 2014. Analysis of the spatial differences in the phytoplankton structure was performed in connection with changes of the temperature, salinity and biogenic regime. At the end of the growing season in the phytoplankton community was dominated by destruction processes and the concentration of nutrients in the upper mixed layer was higher than the limiting level. Coccolithophores (Emiliania huxleyi and Discosphaera cf. tubifer) dominanted over investigated area. The maximum values of abundance and biomass of coccolithophores reached 90.4 mln.cell/m³ and 30.8 mgC/m³, drawing up 82% of the total number and 93% of the total biomass of phytoplankton. Influence of transformed the waters of Atlantic origin was observed in the western part of the investigated area. The number of species in the phytoplankton community here was 1.5–2 times lower than in the eastern part of the occupied mostly by Barents Sea water. In the eastern part of the presence of large dinoflagellates Neoceratium spp. (Ceratium spp.) and Dinophysis spp., lower values of chlorophyll a concentration, a higher proportion of pheophytin in the amount of pigment chlorophyll + pheophytin, the high content of ammonia in the upper mixed layer showed that in this area the phytoplankton was at a later seasonal succession stage than the western part.     

Seasonal and Interannual Variations of Heat Fluxes in the Barents Sea Region

Seasonal and interannual variations in adjective heat fluxes in the ocean (dQ_oc) and the convergence of advective heat fluxes in the atmosphere (dQ_atm) in the Barents Sea region have been investigated over the period of 1993–2012 using the results of the MIT regional eddy-permitting model and ERA-Interim atmospheric reanalysis. Wavelet analysis and singular spectrum analysis are used to reveal concealed periodicities. Seasonal 2- to 4- and 5- to 8-year cycles are revealed in the dQ_oc and dQ_atm data. It is also found that seasonal variations in dQ_oc are primarily determined by the integrated volume fluxes through the western boundary of the Barents Sea, whereas the 20-year trend is determined by the temperature variation of the transported water. A cross-wavelet analysis of dQ_oc and dQ_atm in the Barents Sea region shows that the seasonal variations in dQ_oc and dQ_atm are nearly in-phase, while their interannual variations are out-of-phase. It is concluded that the basin of the Barents Sea plays an important role in maintaining the feedback mechanism (the Bjerknes compensation) of the ocean–atmosphere system in the Arctic region.     

Molecular phylogeny of the genus <Emphasis Type="Italic">Chondracanthus</Emphasis> (Rhodophyta), focusing on the resurrection of <Emphasis Type="Italic">C. okamurae</Emphasis> and the description of <Emphasis Type="Italic">C. cincinnus</Emphasis> sp. nov.

Determining the taxonomic status of the red algal genus Chondracanthus based on morphological characters is challenging due to the similarity and high degree of plasticity of the thallus. Since the taxonomic history of several Chondracanthus species remains unclear, we analyzed the plastid rbcL and mitochondrial COI genes of the specimens from Korea and Japan, in combination with morphological observations, to examine their phylogenetic relationships. Our results confirmed the distinction of C. okamurae, which is separated from C. intermedius, and identified a novel species, C. cincinnus sp. nov. Three species (C. okamurae, C. intermedius and C. cincinnus) formed a monophyletic clade with C. tenellus. C. okamurae is distinguished by linear, narrow, cylindrical to compressed, slightly recurved axes, and a high-intertidal to subtidal distribution. It was collected from Korea and Japan, while C. intermedius was identified from Japan only. A new species, Chondracanthus cincinnus sp. nov., is characterized by linear, compressed, strongly recurved axes, and a low-intertidal to subtidal distiribution. Based on the molecular phylogeny using rbcL and COI data, we herein resurrect C. okamurae as a distinct species and identify C. cincinnus as a new species.     

Photosynthetic pigments as indicators of phytoplankton development during spring and summer in Adventfjorden (Spitsbergen)

The study was carried out from April 30 until July 13 of 1997 in Adventfjorden (Spitsbergen). Formation of less saline and warmer surface water (～1 m thick) caused by melting of the fast ice was observed in the fjord during the first days of May. In summer a less saline surface layer was about 3 m thick. Euphotic depth measured under ice sheet reached 12 m, whereas load of mineral matter brought with riverine discharge in summer (the content of total particulate matter in the fjord reached 1.66 kg m^?2) dramatically reduced euphotic zone depth to 0.35 m. By pigment measurement three phases of phytoplankton development in Adventfjorden were distinguished: (1) spring bloom that has started under fast ice and reached maximum in the mid of May, (2) stagnation period in June, (3) increase of pigment concentration in July, what could indicate a start of the next algae bloom. Analyses of chlorophylls and carotenoids revealed that diatoms (chl c, fucoxanthin), and green algae (chl b, lutein) dominated phytoplankton community in the fjord. Moreover, the presence of peridinin indicates the presence of Dinophyta and alloxanthin—the occurence of Cryptophyta. In May and June 1997 phytoplankton appeared mainly in the surface of water, while in July, as a result of inflow of turbulent riverine waters into Adventfjorden, algae cells were pushed down and the highest numbers were observed at the depth ～20 m. Great phaeopigments to chl a ratio (= 0.54) found in the fjord seston in June and July probably shows strong impact of zooplankton grazing on phytoplankton development. High contribution of chlorophyllide a in porphyrin a poll in samples collected under fast ice (chlorophyllide a/chl a ratio = 0.18) reflects the final stage of algal communitie succession in ice, just before spring ice melt and release of biota to oceanic water. Chloropyllide a content during summer was minor or not detectable, demonstrating that diatom cells were in good physiological condition. High chl a allomer/chl a ratio (average = 0.11 for the period investigated) confirms high oxygen concentration in environment of Adventfjorden.     

Species Composition and Distribution of Sibling Species of the Genus <Emphasis Type="Italic">Chironomus</Emphasis> Meigen (Diptera: Chironomidae) in the Curonian and Vistula Lagoons,Baltic Sea

The species compositions of the genus Chironomus in the Curonian and Vistula lagoons are very similar, represented by Ch. plumosus and Ch. balatonicus. In the Curonian Lagoon, in addition to these two species, Ch. muratensis and the first-generation interspecific hybrid Ch. muratensis × Ch. plumosus are also found. In this lagoon, Ch. plumosus occurs most frequently (84%); Ch. balatonicus is considered a subdominant species (24%). In the Vistula Lagoon, on the contrary, the high frequency of occurrence is typical of Ch. balatonicus (89%); for Ch. plumosus, it reaches only 11%. The Ch. plumosus population occupies most of the Curonian Lagoon; Ch. balatonicus is present only in its northern part, from the village of Juodkrante to the city of Klaipeda. In the Vistula Lagoon, Ch. balatonicus is distributed over almost its entire area, while Ch. plumosus is found locally, only near the mouth of the Nogat River. The distribution of the sibling species in the lagoons is determined by the salinity gradient.     

High mortality and poor growth of green mussels, <Emphasis Type="Italic">Perna viridis</Emphasis>, in high chlorophyll-<Emphasis Type="Italic">a</Emphasis> environment

The current study was carried out from May 2014 to April 2015 to estimate the stock status of P. viridis in Marudu Bay. The gonad development was monitored by histological examination, while the population parameters including asymptotic length (L_∞), growth coefficient (K), mortality rate (Z, F and M), exploitation level (E) and recruitment of P. viridis were estimated using the lengthfrequency data. Results of the current study demonstrated that P. viridis in Marudu Bay spawned throughout the year with two major peaks, one in April to May and another one in October to December. The recruitment pattern was continuous with the peak in May to June 2014, which corresponded to the first spawning peak in April. However, no significant recruitment was observed from the second spawning peak due to the difference in spawning timing between male and female populations. The estimated asymptotic length (L_∞), growth coefficient (K), total mortality (Z), natural mortality (M), fishing mortality (F) and growth performance (ф) of P. viridis in Marudu Bay were estimate to be 117 mm, 0.97 yr^-1, 4.39 yr^-1, 1.23 yr^-1, 3.16 yr^-1 and 4.123, respectively. The exponent b of the lengthweight relationship was 2.4 and exploitation level (E) was 0.72. The high mortality, low condition indices and negative allometric of P. viridis in Marudu Bay is caused by a lack of suitable food in the surrounding water.     

Morphological identification of <Emphasis Type="Italic">Alexandrium</Emphasis> species (Dinophyceae) from Jinhae-Masan Bay,Korea

Outbreaks of paralytic shellfish poisoning (PSP) and dense blooms caused by Alexandrium species in Jinhae-Masan Bay, Korea have been nearly annual events for many years. However, excluding some Alexandrium species responsible for PSP, there are no critical reports on the morphology of Alexandrium species in this bay. To identify the Alexandrium species based on detailed morphological features, vegetative cells collected water samples and established by the incubation of resting cysts isolated from sediment trap samples were analyzed. Four species of Alexandrium were identified: Alexandrium affine, A. fundyense, A. catenella, and A. insuetum. Morphological features of these species were basically consistent with those outlined in previous studies. However, the ventral pore and the connecting pore on the sulcal plate, which have been accepted as diagnostic characteristics for the identification of A. fundyense and A. catenella, need to be reevaluated, indicating that useful morphological features for identifying these two species should be recommended to avoid confusion in the classification of species in genus Alexandrium.     

东印度洋5种缘毛类纤毛虫(钟虫属和聚缩虫)水平分布初次报道

腹壁纤毛虫是一种附着在浮游动物上的原生生物,尤其是附着在桡足类和甲壳类上的。而缘毛虫是可以以自由或寄生的形式在世界各沿海地区和港湾处被发现。本研究首次对东印度洋表层至200 m深海域的缘毛类纤毛虫以及其水平分布展开了研究。根据纤毛虫的形态、纤毛结构和茎的形态等的特征,在2014年4月10日至5月13日东印度洋航次的浮游生物拖网样品中鉴定出了五种富腹纤毛虫,海洋钟形虫Vorticella oceanica、交替聚缩虫Zoothamnium alternans、阿拉聚缩虫Zoothamnium alrasheidi、远洋聚缩虫Zoothamnium pelagicum和海洋聚缩虫Zoothamnium marinum。并通过光显微镜和扫描显微镜拍摄的照片,说明了其形态、尺寸和特征。研究结果表明,海洋钟形虫和远洋聚缩虫的分布与硅藻（如,密聚角毛藻Chaetoceros coarctatus）和桡足类（如,短角长腹剑水蚤Oithona brevicornis）等寄主有关,也包括甲藻（如,三角角藻Ceraitum tripose）周围的一些个体。这些附着纤毛虫的分布在东印度洋海域东南区以海洋钟形虫、远洋聚缩虫和海洋聚缩虫为主,而在孟加拉湾北部则有大量的阿拉聚缩虫。这种分布的变化可能是与寄主的分布有关,如桡足类（短角长腹剑水蚤）和硅藻（密聚角毛藻）的分布影响。     

Studying the sea surface slopes using an array of wave gauge sensors

The deviations of the marine surface slope spectra (measured using an array of wave gauge sensors) from the theoretical estimates obtained using the linear spectral model of the wave field are analyzed. It has been indicated that the average measured full slope spectra (the sum of the slope component spectra in the orthogonal directions) is higher than the theoretical estimates by 6% at frequencies from the surface wave spectral peak (f _m ) to 4.5 f _m . The difference between the measured and theoretical estimates of the full slope spectrum rapidly increases at frequencies of f < f _m . At f _m ≈ 0.75 f _m , the average measured full slope spectrum is higher than the theoretical estimate by a factor of more than 5.