Long-period variations in the optical and microphysical parameters of surface aerosol in a Moscow suburb

The mass concentration M of surface submicron aerosol and its condensation activity χ were measured at the Zvenigorod Scientific Station of the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, in 2001–2006. Variations in these quantities on scales of several days to several months are analyzed. It is shown that the occurrence of dense and superdense hazes over central Russia became more frequent during these years. This resulted in a change in the character of the seasonal dependence of the mass aerosol concentration M: ordered oscillations whose amplitude increases from year to year appeared in the seasonal cycle of M. Due to more frequent cases of dense and superdense hazes in 2002–2006, a significant monotonic increase is observed in the annual means of M. The annual mean of M increased more than twofold in 2005 (56 μm/m³) compared to 2001 (23 μm/m³). The time regimes of M and χ are characterized by variations with periods in the vicinity of 10, 20, and 40–50 days, as well as variations with longer periods within 70–100 days. In addition, the variability of mass concentration is of a strongly intermittent character. A cross-spectral analysis has shown that, on the whole, variations in M are coherent with those in χ. If the parameters M and χ vary on the same time scales, then, as a rule, variations in M lag behind variations in χ by several days. To understand the relationship between the parameters M and χ, special investigations, including studies of aerosol composition, are needed.     

东印度洋现生浮游有孔虫

A brief morphometric study of the recent planktonic foraminifera in the eastern Indian Ocean was provided with the taxonomic key to species,synonyms,SEM microphotographs of shells and chamber arrays.By recent classification,currently 20 species representing 13 genera and 6 families(Canderinidae,Heterohelicoidae,Hedbergellidae,Higerigerinoidae,Globigerinoidae,and Globorotaloidae)identified from the planktonic material of the eastern Indian Ocean up to a depth of 200 m.Their distribution in water(0–200 m)also reports on the new range of expansion in the eastern Indian Ocean,with Dentigloborotalia anfracta,Hastigerina pelagica,Streptochilus globigerus,Globigerinella calida,Globigerinella adamsi,Orcadia reidelii,Tenuitella parkerae,Tenuitella compressa,reported for the first time in this study area.In general,only around 50 planktonic species are valid worldwide,more specifically the species,e.g.,H.pelagica,G.calida,G.adamsi,S.globigerus,O.riedeli,T.parkerae,T.compressa,which occur in the eastern Indian Ocean to fill the the paucity of the recent regional taxonomic literature and the problematic identification from the eastern Indian Ocean.This work aims to bridge this gap and help scientists,managers,educators and students to identify plankton foraminifers by using species notes and images.     

Estimating the parameters of pulsed sources from data on acoustic waves recorded in the atmosphere

The possibility of estimating the parameters of surface pulsed sources from data on acoustic waves recorded in the atmosphere is studied. Experimental values are given for peak pressure P ₊ of recorded acoustic signals, wave-profile area S ₊ in their positive phase, and length t ₊ of this phase, and the approximations of these parameters are obtained within wide ranges of source energy 10^–3 < E < 10¹⁰ kg TNT and scaled distances 1 < R/E ^1/3 < 4 × 10⁴ m/kg^1/3. Conventional methods of estimating the acoustic energy E according to data obtained from acoustic measurements in the atmosphere are analyzed, and ways to improve their accuracy are proposed. The influence of the type of explosions on the parameters P ₊, S ₊, and t ₊ of acoustic signals at long distances R/E ^1/3 > 500 m/kg^1/3 from explosions is shown.     

Determining the influence of wind-wave breaking on the dissipation of the turbulent kinetic energy in the upper ocean and on the dependence of the turbulent kinetic energy on the stage of wind-wave development

New experimental data that make it possible to explain and predict the observed variability of turbulent-energy dissipation in the upper ocean are discussed. For this purpose, the dependence of the energy dissipation rate of breaking wind waves on their propagation velocity (see [1]) is used. The turbulent-energy dissipation values obtained earlier in [2, 3] by a direct method are compared to the results of radar measurements of individual breaking events presented in [1]. On the basis of this comparison, a strong dependence of the turbulent-energy dissipation value on the stage of wind-wave development, which is characterized by the ratio U _a /c _p (U _a is the wind speed and c _p is the phase speed of the peak of the wind-wave spectrum) is confirmed. This dependence was found earlier purely empirically. Moreover, it is shown that the theoretically obtained dependence (c _p /U _a )⁴, does not contradict the available empirical data. The results of this study opens possibilities for scientifically substantiated calculations of greenhouse-gas exchange (specifically, CO₂ exchange between the ocean and the atmosphere).     

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.     

On four closely related hypotrichous ciliates (Protozoa, Ciliophora, Spirotrichea): molecular characters, interspecific relationships and phylogeny defined with multigene sequence information

In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates, Holosticha-complex, four closely related holostichids (five populations), Holosticha bradburyae, H. diademata, Anteholosticha sp., and A. manca, were compared and analyzed using ITS2 secondary structures, ITS1-5.8S-ITS2 region and SSrRNA gene sequences. The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced, and they shared sequence identities ranging from 68.0% to 90.1%, while two populations of Anteholosticha sp. differed in three nucleotides (sequence identity 99.8%). There were several minor differences among ITS2 secondary structures of these species, while two populations of Anteholosticha sp. had the identical secondary structure. Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms (Neighbor-Joining, Maximum Parsimony and Bayesian) revealed similar topologies. The results show that:(1) Holosticha bradburyae and H. diademata firmly clustered together with strong bootstrap supports, forming a sister clade with Anteholosticha sp., (2) Anteholosticha appeared to be a paraphyletic assemblage, in which the morphotype A. manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp. Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha, nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes.     

Seasonal and interannual variation in mesozooplankton community structure off Tongyeong,southeastern coast of Korea,from 2011 to 2014

Mesozooplankton community structure and environmental factors were monitored monthly at a fixed station off Tongyeong, southeastern coast of Korea, from 2011 to 2014 to better understand the variability of the mesozooplankton community in relation to changes in the marine environment. Total mesozooplankton density varied from 747 to 8,945 inds. m^-3 with peaks in summer. The surface water temperature (r = 0.338, p < 0.05) and chlorophyll-a (Chl-a) concentration (r = 0.505, p < 0.001) were parts of the factors that may have induced the mesozooplankton peaks in summer. Copepods accounted for 71% of total mesozooplankton. Total copepod density, particularly cyclopoid copepods, increased during the study period. Cumulative sum plots and anomalies of the cyclopoid copepod density revealed a change of the cyclopoid density from negative to positive in June 2013. A positive relationship between cyclopoid copepods and the Chl-a concentration (r = 0.327, p < 0.05) appeared to be one of the reasons for the increase in cyclopoids. Dominant mesozooplankton species such as Paracalanus parvus s.l., Oikopleura spp., Evadne tergestina, Cirripedia larvae, Corycaeus affinis, Calanus sinicus, and Oithona similis accounted for 60% of total mesozooplankton density. Based on cluster analysis of the mesozooplankton community by year, the seasonal distinction among groups was different in 2014 compared to other years. P. parvus s.l. and its copepodites contributed most in all groups in all four years. Our results suggest that the high Chl-a concentration since 2013 may have caused the changes in mesozooplankton community structure in the study area.     

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.     

Effects of temperature on growth,photophysiology, Rubisco gene expression in <Emphasis Type="Italic">Prorocentrum donghaiense</Emphasis> and <Emphasis Type="Italic">Karenia mikimotoi</Emphasis>

To explore the effects of temperature changes on dinoflagellate bloom succession in the coastal waters of the East China Sea, changes in the growth, photophysiology, and Rubisco gene expression of Prorocentrum donghaiense and Karenia mikimotoi, two harmful algal species, were investigated at different temperatures (16 to 28°C). The maximal specific growth rate and the maximal mRNA expression of Rubisco gene in P. donghaiense and K. mikimotoi occurred at 20 and 24°C, respectively. The photosynthetic activity of P. donghaiense was generally stable, but K. mikimotoi photosynthesis increased when temperatures rose from 16 to 28°C. The effective photochemical efficiency (F _q ^′ /F _m ^′ ) and the maximal relative electron transfer rate (rETR_max) of K. mikimotoi increased significantly with increasing temperature, and the lowest and highest values occurred at 16 and 28°C, respectively. It seems that P. donghaiense has higher photosynthetic capacity than K. mikimotoi due to its higher F _q ^′ /F _m ^′ , rETR_max, and photosynthetic efficiency (α). However, K. mikimotoi has a higher growth rate than P. donghaiense. These results suggest that the photosynthetic activity and genetic responses of dinoflagellates are species-dependent. It is likely that temperature changes affect species composition during blooms, leading to the observed patterns of bloom succession.     

A Baseline Assessment of Coral Reef in Malacca Straits,Malaysia

Coral reefs along the Malacca Straits (MS) are poorly developed mainly due to turbidity and sedimentation. This study describes the health status and community structure of the corals in Cape Rachado, West Coast of Peninsular Malaysia (WCPM), utilizing the Coral Video Transect (CVT) technique. All the survey transects were categorized as ‘fair’ coral conditions (27.39 ± 5.41%–48.56 ± 18.96%) with the reef floor mainly covered by corals and sediment. Twelve families of coral comprised of 25 distinct genera were identified. Coral communities were differentiated into four clusters with each being predominated by Galaxea, Diploastrea, Fungia and Pectinia respectively. Among all, Pectinia is the most spectacular genera and dominated the survey area. Along the MS, Favia, Favites and Porites are commonly found while Porites and Pectinia dominated the reefs. Low coral cover and diversity was recorded in MS as compared to the reefs in the South China Sea (SCS). The most prominent results include changes in the dominant coral from Porites to Pectinia while some species such as Acropora were absent from the study area. Based on the presented data, the reef in the study area was predominantly occupied by sediment and the coral communities were formed by a species with a high tolerance to turbidity and sedimentation.     

海南莺歌海青木刚毛藻及其附生藻的研究——形态分类、形态建成及环境适应

Based on specimens collected in Yinggehai, Hainan, China from 2013 to 2016, a stable epiphytic taxon is found on the surface of the individual of marine green alga Cladophora aokii Yamada. According to the morphological characteristics, the taxonomy of Cl. aokii and its epiphytes is carried out. There are some epiphytes attached on Cl. aokii Yamada including Cl. fascicularis(Mertens ex C. Agardh) Kützing, Chaetomorpha pachynema(Montagne) Kützing, Ceramium camouii Dawson, Licmophora abbreviata Agardh, Lyngbya sp. and Chattonella sp.. The formation of the individual of Cl. aokii is dissected and explained, which can help to analyze the adaption in details among this species, its epiphytes and native marine environment. The results reveal the marine macroepiphytic taxonomy in Hainan, China, and preliminarily explain the adaptive relationship between macroalgae and environment.     

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.     

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.     

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.     

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.     

Simulating the Propagation of Infrasonic Waves and Estimating the Energy of the Chelyabinsk Meteoroid Explosion Observed on February 15, 2013

Results obtained from simulating the propagation of infrasonic waves from the Chelyabinsk meteoroid explosion observed on February 15, 2013, are given. The pseudodifferential parabolic equation (PDPE) method has been used for calculations. Data on infrasonic waves recorded at the IS31 station (Aktyubinsk, Kazakhstan), located 542.7 km from the likely location of the explosion, have been analyzed. Six infrasonic arrivals (isolated clearly defined pulse signals) were recorded. It is shown that the first “fast” arrival (F) corresponds to the propagation of infrasound in a surface acoustic waveguide. The rest of the arrivals (T1–T5) are thermospheric. The agreement between the results of calculations based on the PDPE method and experimental data is satisfactory. The energy E of the explosion has been estimated using two methods. One of these methods is based on the law of conservation of the acoustic pulse I, which is a product of the wave profile area S/2 of the signal under analysis and the distance to its source E _I [kt] = 1.38 × 10^–10 (I [kg/s])^1.482. The other method is based on the relation between the energy of explosion and the dominant period T of recorded signal E _T [kt] = 1.02 × (T [s]²/σ)^3/2, where σ is the dimensionless distance determining the degree of nonlinear effects during the propagation of sound along ray trajectories. According to the data, the explosion energy E _I,T ranges from 1.87 to 32 kt TNT.     

西太平洋深海海水中乙醛降解菌多样性及群落结构研究

As a major aldehyde pollutant widely existing in industry and our daily life, acetaldehyde is more and more harmful to human health. As characteristic habitat niche, bacteria from deep sea environments are abundant and distinctive in heredity, physiology and ecological functions. Thus, the development of acetaldehyde-degrading bacteria from deep sea provides a new method to harness acetaldehyde pollutant. Firstly, in this study,acetaldehyde-degrading bacteria in the deep sea water of the West Pacific Ocean were enriched in situ and in the laboratory respectively, and then the diversity of uncultured bacteria was studied by using 16 S r RNA genes. Then acetaldehyde-degrading strains were isolated from two samples, including enrichment in situ and enrichment in laboratory samples of deep sea water from the West Pacific Ocean using acetaldehyde as the sole carbon source,and then the ability of acetaldehyde degradation was detected. Our results showed that the main uncultured bacteria of two samples with different enrichment approaches were similar, including Proteobacteria,Actinobacteria, Firmicutes, Cyanobacteria, but the structure of bacterial community were significant different.Four subgroups, α, γ, δ and ε, were found in Proteobacteria group. The γ-Proteobacteria was dominant(63.5%clones in laboratory enriched sample, 75% clones in situ enriched sample). The species belonged to γ-Proteobacteria and their proportion was nearly identical between the two enrichment samples, and Vibrio was the predominant genus(45% in laboratory enriched sample, 48.5% in situ enriched sample), followed by Halomonas(9% in situ enriched sample) and Streptococcus(6% in laboratory enriched sample). A total of 12 acetaldehyde-degrading strains were isolated from the two samples, which belonged to Vibrio, Halomonas,Pseudoalteromonas, Pseudomonas and Bacillus of γ-Proteobacteria. Strains ACH-L-5, ACH-L-8 and ACH-S-12,belonging to Vibrio and Halomonas, have strong ability of acetaldehyde degradation, which could tolerate 1.5 g/L acetaldehyde and degrade 350 mg/L acetaldehyde within 24 hours. Our results indicated that bacteria of γ-Proteobacteria may play an important role in carbon cycle of deep sea environments, especial the bacteria belonging to Vibrio and Halomonas and these strains was suggested for their potentials in government of aldehyde pollutants.     

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.     

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).