Bay Sea Research Articles

MYCOBIOTA OF THE RED ALGAE PALMARIA PALMATA IN THE KANDALAKSHA BAY OF THE WHITE SEA

This is a rst report about the diversity of micromycetes associated with living thalli of the edible red algae Palmaria palmata (dulse). We collected samples in the Kandalaksha Bay of the White Sea at upper (10 thalli in the littoral) and lower (10 thalli in the sublittoral) lines of this species distribution. The work was carried out by cultural methods, fungi were isolated from the surface of thalli. From one thallus from 0 to 55 colonies belongs to 0-24 morphotypes were isolated. The total diversity was 52 morphotypes, of which 48 were mycelia and 4 were yeast. All identi ed yeasts belong to Basidiomycota; among lamentous fungi, 2 species belongs to Zygomycota, and the rest belongs to Ascomycota, the vast majority of which are represented by anamorphic stages. The most diverse genera were Acremonium (10 morphotypes), Penicillium (9) and Cladosporium (6); the most numerous are Acremonium (158 colonies) and Cladosporium (103 colonies). Acremonium fuci is the most common species on the studied thalli (122 colonies on 15 thalli). The most important factor for the formation of the surface mycobiota of dulse is the habitat: littoral and sublittoral algal populations di er signicantly in the fungal communities number and structure. The thalli of the littoral population are much richer in fungi. The mycobiota of littoral samples in dominated by dark-colored species, as well as Acremonium fuci and Sarocladium strictum. While the mycobiota of sublittoral samples is dominated by lightcolored species, and most of the isolated yeasts were also founded here.

Monitoring of monthly scale chlorophyll concentration variability in the Bay of Bengal and Arabian Sea using MODIS Aqua Satellite Data

Study has been carried out to monitor the phytoplankton biomass in Bay of Bengal (BoB) and Arabian Sea (AS) using Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite data. Cloud masking, geometric corrections and subsets generations were performed to retrieve chlorophyll images from MODIS-Aqua data during the periods January - December for the years 2007 and 2008. The two regions (BoB & AS) have been divided into four subsets; subset-1 (Northern Bay of Bengal), subset-2 (Southern Bay of Bengal), subset-3 (Northern Arabian Sea) and subset-4 (Southern Arabian Sea). The results were analyzed and confirmed that chlorophyll concentration mean range was high (0.97-1.89 mg m-3) in northern Arabian Sea during the months of July for both years 2007 and 2008 and low concentration range (0.12-0.35 mg m-3) was obtained during April month for both years in southern Bay of Bengal. This study found to be important as information about the chlorophyll concentration in the Northern Indian Ocean.

Influence of Some Environmental Factors on Summer Phytoplankton Community Structure in the Varna Bay, Black Sea (1992–2019)

During the last decades, a decrease in the nutrients and an increase in marine temperature on the surface of the Varna Bay of the Black Sea have been registered. The main aim of this study was to establish the influence of some environmental factors (SST, TP, DIN) on the structure of the phytoplankton and to define what part of these dynamics results from the changes in temperature. Bivariate correlation and Nonlinear regression analyses were used to establish the connection between factors of the environment and the quality parameters of different size and taxonomic groups of phytoplankton. The rising SST proved to statistically significantly influence the decrease in the abundance of nano-phytoplankton (50.9%), the abundance and biomass of micro-phytoplankton (53%; 33.2%), the Bacillariophyceae (49.5%; 35.6%), and the biomass of the species of group “Other” (51.4%). The decreasing TP has a significant influence on the decrease in the abundance and biomass of the diatoms and the biomass of group “Other”. The decreasing DIN significantly affects the decrease in the abundance and biomass of Dinophyceae. The analyses showed that rising temperatures had a leading role in the changes in the taxonomic and size structure of phytoplankton during the period 1992–2019.

Identifying moisture transport pathways for north‐west India

The isotopic composition (δ18O and δ2H) of precipitation is widely used as a moisture source tracer. In north‐west India, the δ18O, δ2H and D‐excess values of precipitation correlate mainly with air temperature; however, the moisture sources of water vapour are unclear. Therefore, we collected daily precipitation isotope data (n = 425) from 13 rain gauge stations in northwest India in 2013. We established a regional meteoric water line (MWL) for northwest India and local MWLs for all 13 rain gauge stations separately. We observed an altitudinal gradient of about 0.11‰/100 m in slope and about 1.22‰/100 m in intercept from the western to the northeast part of the study area. The isotopic composition of precipitation shows spatial and temporal variability across the study area. We found higher Deuterium excess values during winter (December–February) and lower during the monsoon season (July–September), which may be associated with the different moisture sources, namely, the Bay of Bengal, Arabian Sea and Westerly disturbances. Our results suggest local moisture recycling may also occur during the study period. The present study can enhance the knowledge of the isotopic evolution of precipitation and moisture sources in northwest India.

Revisiting the Biostratigraphic Range and Possible Cause of the First and Last Occurrence of Globigerinoides Ruber (Pink) in the Northern Indian Ocean

Abstract The first and last occurrence datums of species are often used as biostratigraphic markers to establish chronology beyond the range of radiocarbon dating. One such datum, the last occurrence of Globigerinoides ruber (pink) from the Indo-Pacific region, has been extensively used as a biostratigraphic marker. However, the first occurrence of G. ruber (pink) in the Indian Ocean and the possible causes thereof are debated. We report the first and last occurrence datums of G. ruber (pink) from the northern Indian Ocean and explore the possible reasons for its first and last occurrence. The first occurrence of G. ruber (pink) in the Bay of Bengal is 399 ka. The last occurrence datums are 128 ka and 123 ka in the Bay of Bengal and Arabian Sea, respectively. The occurrence of G. ruber (pink) in the Indian Ocean is attributed to its invasion through the warmer southeast Atlantic Ocean via the Agulhas Return Current. Based on the synchronous occurrence during Marine Isotopic Stage 11, we propose that the first occurrence of G. ruber (pink) can be used as an additional marker throughout the northern Indian Ocean.

Изучение уровня эвтрофикации прибрежных вод Гданьского залива Балтийского моря с использованием данных дистанционного зондирования Земли

Paper presents an analysis of eutrophication level of Baltic Sea based on the satellite images analysis. Methodologically, the analysis was based on level of the normalized difference vegetation index estimation. Studies was conducted in Gdansk Bay of the Baltic Sea in the Kaliningrad region, based on deposit data for the period from May to September, 2013-2021. It has been established that in the region under study there is a peak in the level of eutrophication in 2017-2019, with a gradual decline in 2019-2021, associated with the stagnation of production processes that introduce nutrients into the waters of the Baltic Sea. A general increased value of normalized difference vegetation index for the coastal waters of the Baltic Sea was noted in comparison with background level.

Modeling the long-term fate of polycyclic aromatic hydrocarbons (PAHs) and public health risk in Bohai Bay Sea Area, China

The target of this study was to reconstruct the historical concentration, distribution, variation, and exposure risk evaluation for EPA PAHs to the whole sea of Bohai Bay and the coastal population, by employing a specific dynamic multimedia model during 1950–2050. The unsteady-state model, driven by temporal energy activities from 1950 and sustainable scenarios based on socioeconomic development, indicated the annual emission increased by 4.6 times (from 84.8 tons to 391 tons) until 2020 and resulted in concentrations up to 5.2 times in the atmospheric compartment, and 4.9 times in seawater. Two peak concentrations in 1997 and 2014, consistent with total PAHs input revealed significant regional anthropogenic input in northern Bohai Bay (Tianjin) and southern Bohai Bay (Hebei). The peak-to-peak values of the timing concentration revealed a notably alternative increase in the south (+109.4 %–128.6 %), instead of the rapid decline in the north (−21.5 %–44.5 %). The dominant processes at air-seawater interfaces were air-seawater molecular transfer (from 38.4 % to 51.8 %), and wet deposition (from 60.5 % to 47.5 %). Under 5 shared socioeconomic pathways, the optimal scenario (SSP1) achieved a 24.7 % emission decline, an atmospheric decrease of 15.1 %–31.1 %, and 24.8 %–41.2 % mitigation in seawater during 2020–2050, and each pathway exhibited a general lessening concave in the northern developed municipality, compared with convex in the southern developing regions. The inhalation risk assessment evaluated 10 generations living on Bohai Bay coasts, with an acceptable result, while the current sustainable conceive was with meager fruition in reducing risk.

Eurytemora gracilicauda (Copepoda: Calanoida) in the Russian Arctic

As a result of studying the populations of Eurytemora genus crustaceans from the internal reservoirs of the drainage basin of the White, Pechora Seas, the Lena deltas, Island of Wrangel and Kamchatka peninsula was set that the species Eurytemora gracilicauda is common along the entire northern border of Russian Eurasia. It was shown that the species distribution for populations from the rockpools of the Kandalaksha Bay of the White Sea, from Lake on Kashin Island in the Pechora Sea and from the Lena River Delta was sequentially along the coast of the Arctic. Studies are based on genetic (parts of CO1 and ITS1 genes) and morphological analyzes of the studied populations. The synonymy of the Kamchatka species E. kurenkovi and E. gracilicauda was confirmed by the morphological analysis. Variation coefficients (CV), calculated for the populations of females from the White Sea, the Lena River delta and from the Kamchatka do not exceed 10%, which indicates a low morphological variability of the species. The most widely represented in the genetic analysis, the White Sea population has a low level of genetic variability, which, together with significant tolerance to the fluctuations of salinity in the rockpools in which it lives, may indicate its recent introduction to the region. A phylogenetic reconstruction was not revealed reliable topology for the species E. gracilicauda. It was shown that E. gracilicauda is not related to the affinis group species. Molecular Clocks with use part of CO1 gene and paleontological calibration revealed the speciation of E. gracilicauda species on the Paleocene – Late Cretaceous boundary. We also can hypothesize a Laurasian origin of the Eurytemora genus.

Simulating Meteorological and Water Wave Characteristics of Cyclone Shaheen

The Bay of Bengal and Arabian Sea are annually exposed to severe tropical cyclones, which impose massive infrastructure damages and cause the loss of life in coastal regions. Cyclone Shaheen originally generated in the Bay of Bengal in 2021 and translated a rare east-to-west path toward the Arabian Sea. Although the cyclone’s wind field can be obtained from reanalysis datasets such as ERA5 (fifth generation European Centre for Medium-Range Weather Forecasts), the wind speed cannot be reproduced with realistic details in the regions close to the center of cyclone due to spatial resolution. In this study, to address this problem, the high-resolution advanced Weather Research and Forecasting (WRF) model is used for simulation of Shaheen’s wind field. As a critical part of the study, the sensitivity of the results to the planetary boundary layer (PBL) parameterization in terms of the track, intensity, strength and structure of the cyclone Shaheen is investigated. Five experiments are considered with five PBL schemes: Yonsei University (YSU); Mellor–Yamada–Janjić (MYJ); Mellor–Yamada–Nakanishi–Niino level 2.5 (MYNN); Asymmetric Convective Model version 2 (ACM2); Quasi-Normal Scale Elimination (QNSE). The track, intensity, and strength of the experiments are compared with the wind fields obtained from the Joint Typhoon Warning Centre (JTWC) dataset. The results imply the high dependency of the track, intensity, and strength of the cyclone to the PBL parameterization. Simulated tracks with non-local PBL schemes (YSU and ACM2) outperformed those of the local PBL schemes (MYJ, MYNN, and QNSE), especially during the rapid intensification phase of Shaheen before landfall. The YSU produced highly intensified storm, while the ACM2 results are in better agreement with the JTWC data. The most accurate track was obtained from the ERA5 data; however, this dataset overestimated the spatial size and underestimated the wind speed. The WRF model using either YSU or ACM2 overestimated the wind speed compared to that of the altimeter data. The YSU and ACM2 schemes were able to reproduce the observed increase in wind speed and pressure drop at in situ stations. The wind data from EAR5 and cyclone parametric model were applied to the SWAN model to simulate the wave regime in the Arabian Sea during the time that Shaheen was translating across the region. Janssen formulation for wind input and whitecapping dissipation source terms in combination with both ERA5 and hybrid wind were used and the minimum combined error in the prediction of significant wave height (Hs) and zero up-crossing wave period (Tz) was examined. The maximum significant wave height for hybrid wind is higher than that of ERA5, while the cyclone development was successfully inferred from the wave field of the hybrid data.

Littoral phytocenoses of marshes located in different tidal conditions of the White Sea

This paper describes the distribution of plant communities from various associations, identified from the standpoint of the ecological-phytocenotic approach, occupying the tidal flat of low and medium marshes, which are under the influence of tide range, different values of pH and water salinity. According to the degree of pH influence, we identified acidotrophic, alkalotrophic, and indifferent phytocenoses, combined into different associations. Most associations of the estuaries with different tide range are alkalotrophic, there are noticeably fewer acidotrophic ones; a few eurytopic communities from the Phragmitetum australis, Bolboschoenetum maritimae, and Caricetum aquatilis associations are classified as indifferent. The study shows that the coastal vegetation of the marshes of the mesotidal estuaries of the White Sea develops in stable pH conditions in the range from 7.2 to 7.6. The formation of coastal vegetation is less stable in the macrotidal estuaries of the Mezen Bay, most of them form at pH = 7.0-8.3. Halophyte vegetation forms in the widest range of pH (6.2-8.3) in the marshes of microtidal estuaries in the Dvina Bay of the White Sea, which are more affected by floods than other estuaries. The halophytic vegetation of the White Sea develops in a wide range of salinity fluctuations from brackish to marine waters. However, the majority of plant associations in the rivers estuaries occupy the habitats of weakly saline waters with 10 to 25% salinity.

Seasonal distribution of ringed seal in the White Sea monitored by satellite tagging

Data on the seasonal distribution and ecology of ringed seals (Pusa hispida) were obtained from the results of seal tagging with satellite telemetry transmitters (STT) in the White Sea. STT "Pulsar" worked in the Argos system. Catching and tagging of ringed seals were carried out in the Dvina Bay of the White Sea in autumn 2008 and 2016 and in the summer of 2020. 5 tags were installed on seals of different ages. It was shown in the summer the ringed seals did not make long movements and remained on the littoral. The seals moved long distances in autumn, the average daily distance between observation points was 43 km per day. The ringed seal preferred areas with open water and the sea edge of landfast ice in winter. The ringed seal could stay for more than two months in the pelagic zone above the depth of 20 m. Priority directions of movement haven’t been identified. We suggest this feature of the seals' behavior in the White Sea is associated with the seasonal distribution of food.

Morphological and molecular systematics of swimming crabs (Decapoda: Brachyura: Portunidae) from India collected on-board the FORV Sagar Sampada (cruise no. 378, 385 and 392), with notes on biogeography of the Indian portunid fauna.

Morphological and molecular characters of swimming crabs (Family Portunidae Rafinesque-Schmaltz, 1815) collected during one cruise each of the Fishery Oceanographic Research Vessel Sagar Sampada in the northeastern Arabian Sea (97–110 m depth), southwestern Bay of Bengal (56 m), and southeastern Bay of Bengal (56 m) and western Andaman Sea (53 m) were studied. They are referred to 17 species representing 4 subfamilies, 8 genera and 2 subgenera. Cycloachelous levigatus Koch, 2021, Monomia rubromarginata (Lanchester, 1900), Thalamita malaccensis Gordon, 1938 are first records from Indian waters. The study also reveals variations in the pleonal and genital morphology of Monomia argentata (A Milne Edwards, 1861) form B (sensu Stephenson and Rees, 1967a). Mitochondrial Cytochrome oxidase subunit I and 16S rRNA gene sequences of 14 and 16 species, respectively revealed a monophyletic subfamily Lupocyclinae Alcock, 1899, and polyphyletic subfamilies Portuninae Rafinesque, 1815 and Thalamitinae Paulson, 1875. Analysis of the biogeographic distribution patterns of Indian portunids revealed a total of 104 species representing 22 genera, thereby suggesting mixed diversity in different ecological regions. The highest number of 72 species and 2 subspecies were recorded from the West and South Indian Shelf Province followed by Andaman Province (69 species), Bay of Bengal Province (54 species) and Central Indian Ocean Islands Province (26 species). Among the individual marine ecoregions, Andaman and Nicobar Islands recorded the highest number of species (69 species), followed by South India (57), Eastern India (50), Western India (47), Northern Bay of Bengal (32) and Maldives (26).

A Comparison of Wave Spectra during Pre-Monsoon and Post-Monsoon Tropical Cyclones under an Intense Positive IOD Year 2019

The impact of Indian Ocean Dipole (IOD) events on the generation and intensity of tropical cyclones under the influence of monsoons is explored. The standardized sea surface temperature (SST) anomalies are computed for the pre-monsoon and post-monsoon months for the Bay of Bengal (BOB) and Arabian Sea (AS) from 1971 to 2020 and relationships are analyzed with the frequency of tropical cyclones for the neutral, positive and negative IOD years. Ocean states are sensitive to cyclonic conditions exhibiting a complex spectral distribution of the wave energy. Due to a tropical cyclone, the surface waves remain under high wind forcing conditions for prolonged periods generating a huge amount of energy. The spectral wave model SWAN (Simulating WAves Nearshore) is used to generate the energy density spectra during FANI (26 April–5 May 2019), which was a pre-monsoon extreme severe cyclonic storm, and BULBUL (5–12 November 2019), which was a post-monsoon very severe cyclonic storm in the BOB region. This study aims to estimate the intensity of wave energy during tropical cyclones in the pre- and post-monsoon months for 2019 (an extremely positive IOD year).

Holocene Paleoenvironmental Implications of Diatom, Non-Pollen Palynomorph, and Organic Carbon Records from the Kandalaksha Bay of the White Sea (European Arctic)

Variations in sea surface conditions and sea level through the Holocene in the Kandalaksha Bay, the White Sea, were reconstructed based on the study of core sediments from the outer Kandalaksha Bay, using the modern analog technique applied to dinocysts in addition to diatoms, TOC, δ13Corg, CaCO3, and grain size data. The chronostratigraphy of the core sediments was defined from accelerator mass spectrometry 14C dates on mollusk shells. The results indicated an increase in water depth in the outer Kandalaksha Bay and in the central Dvina Bay until the late Holocene. From about 9.5 to 7.5 cal kyr BP, the data suggested a general trend of increasing sea surface temperatures (up to 14 °C), at least in areas with inflow of Atlantic waters. The last 2.5 kyr were characterized by increased freshwater runoff to the White Sea.

European heatwaves: Link to large‐scale circulation patterns and intraseasonal drivers

AbstractThis study examines the European heatwaves' predictability at subseasonal timescales. Land surface feedbacks and tropical convection, due to their variability at intraseasonal timescales, are taken into consideration and their potential role in extending the predictability beyond the medium range (10 days) is explored. A classification of European heatwaves into five heatwave types is used to discriminate the effects of surface feedbacks and of tropical variability among the different heatwave types. The classification is computed in terms of circulation patterns. By inferring the near‐surface temperature through atmospheric circulation, we aim to identify the predictable component of the heatwave events. All five heatwave circulation patterns are characterized by persistent anticyclonic anomalies located over the region with maximum temperatures. We show that soil moisture deficit is not a required precondition for the occurrence of heatwaves over most of Europe. However, heatwave events over southern Europe exhibit some sensitivity to dry conditions. We use a simplified index to describe the dominant mode of tropical convection at intraseasonal timescales. The index, based on precipitation anomalies, represents the evolution of the Boreal Summer Intraseasonal Oscillation (BSISO). We find that episodes with strong BSISO amplitudes characterized by enhanced convection over India, Bay of Bengal and China sea favour the occurrence of heatwave events over Russia. The results highlight the role of tropical intraseasonal variability in enhancing the predictability of some extreme temperature events over Europe.

Ecological succession of pico- and nanophytoplankton in a coastal bay of NW Mediterranean sea

The long-term evolution of pico- and nanophytoplanktonic communities in two coastal contrasting sites from the bay of Toulon was studied using monthly flow cytometry analyses during a seven-year period. Results highlighted higher abundance of both pico- and nanophytoplanktonic communities in the more eutrophic site (i. e. the Little Bay). Moreover, even if both sites were widely dominated by Synechococcus spp. population, it represented more than 90% of the population during summer in the Large Bay. Using diversity indices and rank frequency diagrams to study ecological successions in both sites, communities from the Little Bay (the most polluted site) appeared, paradoxically, as more diversified and more mature than that from the Large Bay. Communities from the Large Bay appeared as less diversified and juvenile linked to the dominance of Synechococcus spp. The complementarity of diversity indices and rank frequency diagram was revealed in this present work.

Mesoscale eddies with anomalous sea surface temperature and its relation with atmospheric convection over the North Indian Ocean

AbstractMesoscale eddies are the important phenomenon of world oceans that play a prominent role in influencing the near‐surface atmosphere and transport of heat. Ocean and atmosphere responses due to the presence of oceanic mesoscale eddies are not well studied in the Northern Indian Ocean (NIO) region. The present study analysed the ocean and atmospheric response due to the presence of mesoscale eddies using a composite analysis. Generally, it is assumed that the anti‐cyclonic eddies are associated with the positive anomalies of sea surface temperature (SST), and cyclonic eddies are accompanied by negative anomalies. However, for the two marginal seas in the NIO, that is, the Bay of Bengal (BoB) and Arabian Sea (AS), the composite picture of SST anomalies associated with mesoscale eddies showed an abnormal response of SST. This unusual behaviour of cold SST near anti‐cyclonic eddies and warm SST near cyclonic eddies in BoB and AS is analysed with the mean composites of precipitation, outgoing longwave radiation (OLR), and turbulent fluxes. The mean composites over all anti‐cyclonic eddies reveal the presence of enhanced precipitation and convection (low OLR), whereas over cyclonic eddies, suppressed convection and negative precipitation anomalies are evident. The composites of latent heat flux (LHF), precipitation and OLR near surface cold anti‐cyclonic eddies indicate the loss of heat from the ocean to the atmosphere, intense precipitation along with cloudy conditions are responsible for the cooling of the ocean. Along with this, stronger winds are also evident during cloudy conditions could play a role in anomalous cooling of SST observed near anti‐cyclonic through intense surface mixing. Similarly, vice versa is observed near the surface warm cyclonic eddies. The overlying atmosphere and abnormal response of SST near oceanic eddies are essential for understanding the significant role of oceanic mesoscale eddies in influencing the large‐scale circulation of the atmosphere and climate.

THE EFFECTIVENESS OF QRIS PAYMENTS IN AN ISLAMIC PERSPECTIVE BASED ON PADG NO.24/1/PADG/2022

Kendari city is a religious city, this is marked by the many mosques built in every corner of the city, one of the mosques that has become an iconic place for the people of Kendari city is the al-alam mosque which was built in 2010 which features beautiful views, the al- Alam is located in the middle of the Kendari Bay sea so that it gives a different feel from other mosques in the city of Kendari, the Al-Alam Mosque is a religious tourism destination that is often visited by both local and foreign tourists. The payment system cannot be separated from the development of money, which started from cash payments to non-cash payments. Many development agencies facilitate transactions that are effective in making payments, one of which is QRIS, which is an electronic money payment application such as an electronic wallet, server based. or mobile banking that is used by users for digital money payments is different. QRIS aims to offer a lot of comfort and convenience for its users with a variety of features that are useful and have advantages that are not in doubt the safety and effectiveness of the QRIS payment system for its users.

The severe drought event of 2009–2010 over southwest China as recorded by a cave stalagmite from southeast Yunnan: Implication for stalagmite δ18O interpretation in the Asian monsoon region

It is still debated whether the stalagmite δ18O in the East Asian monsoon region indicates the intensity of the summer monsoon or the precipitation of the summer monsoon season on an annual scale. One key reason for this debate is the lack of accurate comparison between stalagmite δ18O and instrumental records. To better decipher the stalagmite δ18O in the Asian monsoon region on an annual scale, stalagmite PL1 from Pailong Cave, southeast of Yunnan, was selected. The calcite deposited from 2004 to 2019 within stalagmite PL1 was determined by laminar counting, 210Pb dating and seasonal variations in δ13C values. Seasonal scale δ18O, δ13C and Mg/Ca ratios were found to record the severe drought over Southwest China that occurred in 2009–2010. In 2009, when the severe drought was the most intense, the stalagmite δ18O, δ13C, and Mg/Ca ratios changed significantly, reflecting the hydrological response caused by climate change (decrease in precipitation). However, distinct from the δ13C and Mg/Ca ratios, the highest δ18O value was found in 2010, which reflects the influence of the evaporation in the soil and epikarst. On the annual scale, the stalagmites/precipitation δ18O in both Yunnan and eastern China are dominated by El Niño-Southern Oscillation (ENSO) activity. During the El Niño/La Niña phase, reduced/enhanced convective activities but strong/weak water vapor flux transportation occurred in the Bay of Bengal and the South China Sea, and weaker/stronger water vapor flux transportation in the Arabian Sea induced enriched/depleted precipitation δ18O and hence stalagmite δ18O in Yunnan and eastern China. On the interannual scale, the stalagmite δ18O of Yunnan is mainly affected by the strength of the South Asian summer monsoon and water vapor flux transportation from the Arabian Sea. The stronger (weaker) South Asian summer monsoon intensity will induce more (less) water vapor flux transported from the Arabian Sea and depleted (enriched) stalagmite δ18O in Yunnan. Distinct from stalagmite δ18O in Yunnan, the precipitation/stalagmite δ18O in eastern China is significantly correlated with ENSO indices on the interannual scale. Precipitation/stalagmite δ18O in eastern China is dominated by convective activities in the source area (Bay of Bengal-South China Sea).

Bioethanol Production From Tropical Marine Microalgae Ambon Bay Navicula sp. of The Inner Ambon Bay Strain

Microalgae are photosynthetic microorganisms that contain carbohydrates can be converted into glucose through a hydrolysis process so that they can be used as raw materials for bioethanol production. Navicula sp. strain TAD is a type of marine microalgae that is spread in the inner Ambon Bay (TAD) sea waters and is used to manufacture bioethanol. This study aims to determine the content of carbohydrates and bioethanol produced from tropical marine microalgae Ambon bay Navicula sp. strain TAD. The research was conducted through several stages, namely the cultivation of Navicula sp. strain TAD to obtain biomass, determine carbohydrate content in biomass, hydrolyze biomass and manufacture bioethanol through a fermentation process using Saccharomyces cerevisiae. The results showed that Navicula sp. strain TAD cultivation for seven days had the highest cell density of 72.167 × 105 ± 0.946 cells mL-1 with dry biomass of 0.933 ± 0.062 g and productivity of 0.166 ± 0.011 gL-1 hour-1. The sulfuric acid hydrolysis process was analyzed for a sugar content of 146.5695 ± 0.758 mg. A fermentation process follows the results of the hydrolysis to produce bioethanol. The bioethanol content obtained was 6.357%. These indicated that Navicula sp. strain TAD has the potential to produce bioethanol