Liter Of Seawater Research Articles

Expanding sample volume for microscopical detection of nanoplastics

The extent of nanoplastic pollution has raised severe environmental and health concerns. While the means for microplastic detection are abundant, improved tools for nanoplastic detection are called-for. State-of-the-art microscopic techniques can detect nanoplastics down to tens of nanometers, however, only from small sample sizes (typically ∼10μl). In this work, we describe a method that enables sampling of 1 l of seawater by the means of correlative Raman- and SEM-techniques. This is achieved by adapting common microplastic sample purification protocols to suit the nanoplastic study. In addition, we decorate a membrane filter with SERS-property to amplify the Raman signals. Together, the purification method combined with the use of the SERS-activated-membrane-filter enables identification and imaging of individual nanoplastic particles from significantly larger sample sizes than before. In the nanoscale the average recovery rate is 5 %. These results aim to provide useful tools for researchers in the fight against plastic pollution.

Growth of Bamboo Lobster (Panulirus versicolor; Latreille, 1804) Fed with Feed Made from Sosodek Fish Meal (Atherinomorus lacunosus)

Bamboo lobster (Panulirus versicolor) is a marine commodity with promising prospects for aquaculture development. Feed is a critical issue in the growth of P. versicolor, necessitating an effective, affordable solution that promotes optimal growth. This study aimed to examine the use of sosodek fish meal (A. lacunasus) as a nutrient source to enhance the growth of P. versicolor. Specimens of P. versicolor (weighing 79.97±38 g) were obtained from local fishermen in Togean District, Tojo Una-Una Regency, Central Sulawesi. The experiment tested the use of sosodek fish meal as a feed ingredient at different percentages: 0% (control), 10% (A), 20% (B), and 30% (C). The lobsters were kept in containers with 25 liters of seawater, with one lobster per container, and each treatment was replicated three times. Feed was given at 5% of body weight, three times daily. Body weight was measured every two weeks. Water quality was maintained within a range suitable for P. versicolor. The results indicated that weight gain and daily growth rates, from highest to lowest, were observed in treatment C (11.84 g and 0.49%/day), B (7.4 g and 0.21%/day), A (2.82 g and 0.09%/day), and control (2.38 g and 0.08%/day). Feed conversion ratios, from lowest to highest, were recorded as C (13.1), B (25.1), A (71.9), and control (64.0). Feed utilization efficiency, from highest to lowest, was seen in treatment C (10.28%), B (4.32%), A (1.85%), and control (1.72%). Survival rates for all treatments were 100%. The analysis showed that individual weight gain, daily growth rates, and feed utilization efficiency were significantly higher, and feed conversion ratios were lower in treatment C (30% sosodek fish meal) compared to other treatments (P<0.05). Utilizing 30% sosodek fish meal as feed ingredient significantly enhances the growth of P. versicolor.

SMMP: A Deep-Coverage Marine Metaproteome Method for Microbial Community Analysis throughout the Water Column Using 1 L of Seawater.

Marine microbes drive pivotal transformations in planetary-scale elemental cycles and have crucial impacts on global biogeochemical processes. Metaproteomics is a powerful tool for assessing the metabolic diversity and function of marine microbes. However, hundreds of liters of seawater are required for normal metaproteomic analysis due to the sparsity of microbial populations in seawater, which poses a substantial challenge to the widespread application of marine metaproteomics, particularly for deep seawater. Herein, a sensitive marine metaproteomics workflow, named sensitive marine metaproteome analysis (SMMP), was developed by integrating polycarbonate filter-assisted microbial enrichment, solid-phase alkylation-based anti-interference sample preparation, and narrow-bore nanoLC column for trace peptide separation and characterization. The method provided more than 8500 proteins from 1 L of bathypelagic seawater samples, which covered diverse microorganisms and crucial functions, e.g., the detection of key enzymes associated with the Wood-Ljungdahl pathway. Then, we applied SMMP to investigate vertical variations in the metabolic expression patterns of marine microorganisms from the euphotic zone to the bathypelagic zone. Methane oxidation and carbon monoxide (CO) oxidation were active processes, especially in the bathypelagic zone, which provided a remarkable energy supply for the growth and proliferation of heterotrophic microorganisms. In addition, marker protein profiles detected related to ammonia transport, ammonia oxidation, and carbon fixation highlighted that Thaumarchaeota played a critical role in primary production based on the coupled carbon-nitrogen process, contributing to the storage of carbon and nitrogen in the bathypelagic regions. SMMP has low microbial input requirements and yields in-depth metaproteome analysis, making it a prospective approach for comprehensive marine metaproteomic investigations.

Utilization of the heat from combustion of water for the heating process in water desalination

The volume of municipal waste has become a national problem so far, so a solution is needed to reduce the waste problem. One solution to reduce the volume of municipal waste is to burn waste. However, the combustion needs to be designed to take advantage of the heat generated by combustion. In this study, the process of burning waste with various types of waste materials was carried out. The heat of burning waste is used to evaporate 1 liter of seawater and the seawater vapor is cooled to produce distilled water. The volume of distilled water and the precipitated salt were weighed. The results of the research from the variation of 6 types of waste materials obtained that the type of clothing waste material gave the fastest time, which was 43.75 minutes, the amount of distilled water was 931 ml, and salt deposited as much as 30 grams. The test results on distilled water showed that almost all parameters met the requirements of drinking water and obtained a salt content of 84%. Further processing by adjusting the hardness is needed to process distilled water into clean water and the addition of iodine can be considered to produce iodized salt.

Rapid removal and replacement of dissolved organic matter during circulation through ultramafic crust

Large volumes of seawater have passed through the rocky subseafloor throughout Earth's history. The scale of circulation is sufficiently large to impact the cycling of marine dissolved organic carbon (DOC), one of the largest pools of reduced carbon on Earth whose sources and sinks remain enigmatic, and to sequester carbon over geologic timescales. While the fate of DOC in numerous mafic systems has been examined, no previous reports are available on the less studied but still abundant ultramafic systems. We analyzed the concentration and composition of DOC from the Lost City hydrothermal field (30°N, Mid-Atlantic Ridge), a long-lived ultramafic system with minimal magmatic input. We show that per liter of seawater, more DOC is removed and a rate >650 times faster rate than in mafic ridge flank systems. Simultaneously, newly synthesized 14C-free organics are exported into the water column, adding a pre-aged component to the deep DOC pool. The sequestration of oceanic organic molecules onto minerals could partially account for the substantial total organic carbon present in ultramafic rocks, which is currently interpreted as evidence of chemoautotrophy or abiotic synthesis.

Electrochemical ocean alkalinity enhancement using a calcium ion battery

The oceans play a major role in moderating atmospheric CO2 levels. Enhanced CO2 uptake into ocean waters can be achieved by the provision of appropriate cations to the surface ocean, an approach known as ocean alkalinity enhancement (OAE). Here, we present a calcium ion battery approach that enhances alkalinity via electrochemical manipulation of seawater calcium concentrations. We demonstrate the efficacy of this approach using a potassium barium iron cyanide [K2BaFe(CN)6] (PBFC) electrode, a Prussian blue analogue, to move calcium ions from one reservoir of seawater to another. Using material and electrochemical characterization of the Ca2+ ion insertion and expulsion properties of PBFC in synthetic seawater, we determine the repeatability of Ca2+ ion insertion and expulsion from the PBFC electrode. Our analyses prove a 2.75 % increase in seawater alkalinity via the PBFC electrode, which yields 2.64 mg CO2 (0.72 mg C) uptake per liter of seawater. This proof-of-concept method offers a unique, low-cost, energy efficient electrochemical approach for atmospheric carbon dioxide removal that can combine with marine-based renewable energy to enable a new family of effective, scalable climate change solutions.

Simultaneous preconcentration of 9Be and cosmogenic 10Be for determination of the 10Be/9Be ratio in (coastal) seawater

AbstractBeryllium isotopes have emerged as a quantitative tracer of continental weathering, but accurate and precise determination of the cosmogenic 10Be and stable 9Be in seawater is challenging, because seawater contains high concentrations of matrix elements but extremely low concentrations of 9Be and 10Be. In this study, we develop a new, time‐efficient procedure for the simultaneous preconcentration of 9Be and 10Be from (coastal) seawater based on the iron co‐precipitation method. The concentrations of 9Be, 10Be, and the resulting 10Be/9Be ratio for Changjiang Estuary water derived from the new procedure agree well with those obtained from the conventional procedure requiring separate preconcentration for 9Be and 10Be determinations. By avoiding the separate preconcentration, our newly developed procedure contributes toward more time‐efficient handling of samples, less sample cross‐contamination, and a more reliable 10Be/9Be ratio. Prior to this, we validated the iron co‐precipitation method using artificial seawater and natural water samples from the Amazon Estuary regarding: (1) the “matrix effect” for Be analysis, (2) its extraction efficiency for pg g−1 levels Be in the presence and absence of organic matter, and (3) the data comparability with another preconcentration method. We calculated that for the determination of 9Be and 10Be in most open ocean seawater with typical 10Be concentrations of > 500 atoms g−1, good precisions (< 5%) can be achieved using less than 3 liters of seawater compared to more than 20 liters routinely used previously. Even for coastal seawater with extremely low 10Be concentration (e.g., 100 atoms g−1), we estimate a maximum amount of 10 liters to be adequate.

Inter-comparison of marine microbiome sampling protocols

Research on marine microbial communities is growing, but studies are hard to compare because of variation in seawater sampling protocols. To help researchers in the inter-comparison of studies that use different seawater sampling methodologies, as well as to help them design future sampling campaigns, we developed the EuroMarine Open Science Exploration initiative (EMOSE). Within the EMOSE framework, we sampled thousands of liters of seawater from a single station in the NW Mediterranean Sea (Service d'Observation du Laboratoire Arago [SOLA], Banyuls-sur-Mer), during one single day. The resulting dataset includes multiple seawater processing approaches, encompassing different material-type kinds of filters (cartridge membrane and flat membrane), three different size fractionations (>0.22 µm, 0.22–3 µm, 3–20 µm and >20 µm), and a number of different seawater volumes ranging from 1 L up to 1000 L. We show that the volume of seawater that is filtered does not have a significant effect on prokaryotic and protist diversity, independently of the sequencing strategy. However, there was a clear difference in alpha and beta diversity between size fractions and between these and “whole water” (with no pre-fractionation). Overall, we recommend care when merging data from datasets that use filters of different pore size, but we consider that the type of filter and volume should not act as confounding variables for the tested sequencing strategies. To the best of our knowledge, this is the first time a publicly available dataset effectively allows for the clarification of the impact of marine microbiome methodological options across a wide range of protocols, including large-scale variations in sampled volume.

ЭКСПРЕСС-ОЦЕНКА РАЗМЕРНЫХ ФРАКЦИЙ ПЛАНКТОНА В АКВАТОРИИ Г. СЕВАСТОПОЛЬ ЗИМОЙ 2021-2022 ГГ: МОДЕЛЬНЫЕ ИССЛЕДОВАНИЯ

For the purpose of monitoring the water area of Sevastopol a line of devices for plankton macrofiltration in the size range from 2 mm to 2 microns has been developed. Twelve stations have been chosen from Inkerman to Fiolent with total length of 30 km. From piers far out at sea, 50-500 liters of seawater were sampled from the surface and filtered through a system of successive sieves 2 mm, 300, 150, 84 microns and a 2 μm fiber filter. In the winter of 2021-2022, when the seawater temperature was 8 °C, the diversity of plankton morphotypes was low. For all stations, the number of morphotypes increased as the size fraction decreased in the form of ecological pyramids. It was found that the richness of morphotypes in Inkerman is significantly lower than at other stations. Samples from neighboring stations may differ in the composition of morphotypes up to 50% (spatial section). Also, sea water samples taken at the same station with an interval of 1.5 months differed by 50% in the composition of morphotypes (time slice). The obtained results indicate that the developed technique of sequential filtration gives a visual representation of the state of meso-, micro- and nano-plankton in seawater samples.

Proportion Of Daily Abundance Of Phytoplankton Based On Time Changes In Periods Of The Best Incubation Time In Marine Waters

The research aimed to analyzing the proportion of the daily abundance of phytoplankton based on the change in time in the best incubation time period. The implementation of the research from November 2018 to January 2019 in the marine waters of Barrang Lompo Island. Water samples to identify the daily phytoplankton abundance were taken by filtering 100 liters of seawater using a plankton net. Water sampling was carried out at the observation time at 10:00; 11.00; 12.00; 13.00; 14.00 in the best incubation time period (10.00-14.00). Based on the results of the study, the change in the proportion of daily phytoplankton abundance did not differ significantly based on the change in time in the best incubation time period.

Plankton Planet: A frugal, cooperative measure of aquatic life at the planetary scale

In every liter of seawater there are between 10 and 100 billion life forms, mostly invisible, called marine plankton or marine microbiome, which form the largest and most dynamic ecosystem on our planet, at the heart of global ecological and economic processes. While physical and chemical parameters of planktonic ecosystems are fairly well measured and modeled at the planetary scale, biological data are still scarce due to the extreme cost and relative inflexibility of the classical vessels and instruments used to explore marine biodiversity. Here we introduce ‘Plankton Planet’, an initiative whose goal is to engage the curiosity and creativity of researchers, makers, and mariners to (i) co-develop a new generation of cost-effective (frugal) universal scientific instrumentation to measure the genetic and morphological diversity of marine microbiomes in context, (ii) organize their systematic deployment through coastal or open ocean communities of sea-users/farers, to generate uniform plankton data across global and long-term spatio-temporal scales, and (iii) setup tools to flow the data without embargo into public and explorable databases. As proof-of-concept, we show how 20 crews of sailors were able to sample plankton biomass from the world surface ocean in a single year, generating the first seatizen-based, planetary dataset of marine plankton biodiversity based on DNA barcodes. The quality of this dataset is comparable to that generated by Tara Oceans and is not biased by the multiplication of samplers. The data unveil significant genetic novelty and can be used to explore the taxonomic and ecological diversity of plankton at both regional and global scales. This pilot project paves the way for construction of a miniaturized, modular, evolvable, affordable and open-source citizen field-platform that will allow systematic assessment of the eco/morpho/genetic variation of aquatic ecosystems and microbiomes across the dimensions of the Earth system.

The experimental test of the best abasorbents for controlling poly aromatic hydrocarbon on sea water around graving dock and hhip loading terminal

Bentonite and zeolite adsorbents have the ability to adsorb PAH content around the shipyard and ship loading and unloading areas. The factors that potentially affect the level are: a. The types of bentonite and zeolite adsorbents, b. Sampling time is 0, 2, 4, 6 and 8 hours. Adsorption of poly aromatic hydrocarbon by zeolite adsorbent as much as 150 gram done at certain place with volume of 3 liters of sea water taken from ship loading and unloading terminal area and at time variable 0, 7, 14, 28 and 42 days. Measurement of PAH on day 0 by way of direct examination of sea water concentration and PAH type. Determination of the best adsorbent, seen from the ability of the absorption of PAH both in the high concentration and the number of PAH types adsorbed, the results showed that zeolite adsorbents have better adsorption capacity because it has sufficient surface area and does not clot when exposed to water. The concentration of sea water PAH at ship loading and unloading terminal is very high, that is 65,45ppb, especially for PAH type of naphthalene and 2-Bromonaphthalene ie 28,3255 and 27, 2821ppb respectively. The ability of zeolite adsorbent and maximum adsorption of PAH at 28 days adsorption, ie 19, 75ppb is dominated by Benzo(a)pyrene type PAH with concentration of 19,2771ppb. Based on Linear Regression test to total PAh, it can be concluded that the value of R Square 0,190511343 which shows that the absorption time by zeolite absorbent and absorption power of poly aromatic hydrocarbons compound of the whole types has no significant effect. Therefore, polynomial testing is done through the equation y = -8,959x^3+62,858x^2-125,49x+72,379 yield value R^2= 1 which means absorption of 100% polyaromatic hydrocarbons compound in time.

Zooplankton Tintinnopsis dominance in the Estuary of Polong River, Pangkep Regency, South Sulawesi, Indonesia

Genus Tintinnopsis is a microzooplankton from the protozoa (ciliate) group that lives in various habitats in marine waters. Like other zooplankton, Tintinnopsis holds important roles in the food chain. An investigation on the zooplankton community focusing on species composition had been conducted in July 2020 in Polong River estuary, Pangkajene District, South Sulawesi. Sampling was carried out at four stations, each with three replications. Seventy-five liters of seawater were filtered using a plankton net 25 (0.06 mm) into a 100 mL sample bottle and added with 2mL of 1% Lugol. Zooplankton species were counted and identified by putting 1ml of water sample on a Sedgwick Rafter counter and observed on a microscope. Zooplankton identification followed Identification of Marine Plankton and Marine Plankton A Practical Guide. The number of zooplankton differences amongst stations was analyzed statistically by using a one-way ANOVA. Results showed that Tintinnopsis were found in all stations, and were most abundant in station 2, followed by stations 1, 3, and 4. There were two other zooplankton species found in the area, i.e. nauplii Copepoda (stations 1, 3, and 4) and Apocyclops sp (station 2). Each species composition was 80.60%, 18.62% and 0.78% for Tintinnopsis sp., nauplii copepods and Apocyclops sp., respectively. One-way ANOVA also showed no significant differences in the individual abundances amongst station (CI 95%; (p>0.05).

The Study of Coastline Changing and Total Suspended Solid Distribution Based on The Remote Sensing Data in Teluk Lamong Multipurpose Port Terminal

Looking forward to the abovementioned conditions, this research is needed to elaborate on the effects of the reclamation to the marine resources in Teluk Lamong Multipurpose Port Terminal as the reclaimed product. In order to describe the impact of the port development, this study will analyze the shoreline changing, the current pattern modeling, as well as the Total Suspended Solid (TSS) modeling using the remote sensing data. The several numbers of expected objectives through this study are to get the set of scientific information on the shoreline changing in Teluk Lamong Multipurpose Port Terminal in the year of 2012 and 2020, to get the figure of current pattern in Teluk Lamong Multipurpose Port Terminal in the year of 2012 and 2020, and to elaborate TSS concentration through the modeling approach in Teluk Lamong Multipurpose Port Terminal in the year of 2012 and 2020. Hence, there is a set of methodologies and tools to cooperate with the information before and after the reclamation. The use of the Digital Shoreline Analysis System (DSAS) software to analyze coastline conditions. The using of Mike 21 to analyze the current pattern and TSS concentrations. In addition to the TSS analysis, it will also need a set of remote sensing data from the Google Earth Engine (GEE). The modeling and calculation give information about the End Point Rate (EPR) values and TSS values. The EPR values are 107.5 m/year, 59,625 m/year and 10,375 m / year. The TSS values are 0-20 mg/L, 20.1-40 mg/L, 40.1-80 mg/L, 80.1-120 mg/L and >120.1 mg/L. Moreover, the result shows the different values among the length of coastline, the current pattern, and TTS in the years 2012 and 2020. The difference in the coastline reaches 950 m at this latest 8 years. While it also brings the changing to the current pattern and sediment transport which show through its current velocity and sediment content per liter of seawater during high and low tide accordingly.

Penggunaan Rumput Laut (Gracilaria verrucosa) sebagai Agen Biokontrol pada Polikultur Udang Vaname (Litopenaeus vannamei) untuk Mencegah Infeksi Vibrio harveyi

Tujuan dari penelitian ini untuk mengkaji polikultur rumput laut pada budidaya udang vaname skala laboratorium dalam mencegah infeksi V. harveyi. Penelitian dilakukan dengan rancangan acak lengkap (RAL) 3 perlakuan dan 3 ulangan. Perlakuan meliputi penggunaan rumput laut sebanyak 800 gram (P8), 400 gram (P4) dan tanpa rumput laut (Kontrol). Uji tantang dilakukan selama 10 hari dengan konsentrasi bakteri 106 cfu/mL/ekor pada 10 udang di akuarium berisi air laut 100 liter. Hasil penelitian menunjukkan bahwa polikultur rumput laut dengan udang vaname tidak dapat mempertahankan kelangsungan hidup udang secara signifikan namun dapat menekan populasi bakteri V. harveyi di perairan. Kelangsungan hidup udang berturut-turut dari kontrol, P4 dan P8 adalah 60.0%, 73.3%, 76.7%. Jumlah populasi bakteri pada perlakuan lebih rendah dibandingkan dengan kontrol pada hari ke-10 pasca penebaran rumput laut sampai dengan uji tantang. Penggunaan rumput laut juga dapat mempercepat recovery time (masa sembuh) udang dari infeksi bakteri diamati pada gejala klinis yang kembali normal pada hari ke-9 pasca uji tantang. Total hemosit (THC) teramati lebih baik pada udang yang dipelihara dengan rumput laut hari ke-10 pasca uji tantang dan diferensial hemosit (DHC) lebih baik pada hari ke-5 pasca uji tantang. Penggunaan rumput laut pada polikultur udang vaname berpotensi meningkatkan status kesehatan udang.
 Tujuan dari penelitian ini untuk mengkaji polikultur rumput laut pada budidaya udang vaname skala laboratorium dalam mencegah infeksi V. harveyi. Penelitian dilakukan dengan rancangan acak lengkap (RAL) 3 perlakuan dan 3 ulangan. Perlakuan meliputi penggunaan rumput laut sebanyak 800 gram (P8), 400 gram (P4) dan tanpa rumput laut (Kontrol). Uji tantang dilakukan selama 10 hari dengan konsentrasi bakteri 106 cfu/mL/ekor pada 10 udang di akuarium berisi air laut 100 liter. Hasil penelitian menunjukkan bahwa polikultur rumput laut dengan udang vaname tidak dapat mempertahankan kelangsungan hidup udang secara signifikan namun dapat menekan populasi bakteri V. harveyi di perairan. Kelangsungan hidup udang berturut-turut dari kontrol, P4 dan P8 adalah 60.0%, 73.3%, 76.7%. Jumlah populasi bakteri pada perlakuan lebih rendah dibandingkan dengan kontrol pada hari ke-10 pasca penebaran rumput laut sampai dengan uji tantang. Penggunaan rumput laut juga dapat mempercepat recovery time (masa sembuh) udang dari infeksi bakteri diamati pada gejala klinis yang kembali normal pada hari ke-9 pasca uji tantang. Total hemosit (THC) teramati lebih baik pada udang yang dipelihara dengan rumput laut hari ke-10 pasca uji tantang dan diferensial hemosit (DHC) lebih baik pada hari ke-5 pasca uji tantang. Penggunaan rumput laut pada polikultur udang vaname berpotensi meningkatkan status kesehatan udang.
 Tujuan dari penelitian ini untuk mengkaji polikultur rumput laut pada budidaya udang vaname skala laboratorium dalam mencegah infeksi V. harveyi. Penelitian dilakukan dengan rancangan acak lengkap (RAL) 3 perlakuan dan 3 ulangan. Perlakuan meliputi penggunaan rumput laut sebanyak 800 gram (P8), 400 gram (P4) dan tanpa rumput laut (Kontrol). Uji tantang dilakukan selama 10 hari dengan konsentrasi bakteri 106 cfu/mL/ekor pada 10 udang di akuarium berisi air laut 100 liter. Hasil penelitian menunjukkan bahwa polikultur rumput laut dengan udang vaname tidak dapat mempertahankan kelangsungan hidup udang secara signifikan namun dapat menekan populasi bakteri V. harveyi di perairan. Kelangsungan hidup udang berturut-turut dari kontrol, P4 dan P8 adalah 60.0%, 73.3%, 76.7%. Jumlah populasi bakteri pada perlakuan lebih rendah dibandingkan dengan kontrol pada hari ke-10 pasca penebaran rumput laut sampai dengan uji tantang. Penggunaan rumput laut juga dapat mempercepat recovery time (masa sembuh) udang dari infeksi bakteri diamati pada gejala klinis yang kembali normal pada hari ke-9 pasca uji tantang. Total hemosit (THC) teramati lebih baik pada udang yang dipelihara dengan rumput laut hari ke-10 pasca uji tantang dan diferensial hemosit (DHC) lebih baik pada hari ke-5 pasca uji tantang. Penggunaan rumput laut pada polikultur udang vaname berpotensi meningkatkan status kesehatan udang.
 Tujuan dari penelitian ini untuk mengkaji polikultur rumput laut pada budidaya udang vaname skala laboratorium dalam mencegah infeksi V. harveyi. Penelitian dilakukan dengan rancangan acak lengkap (RAL) 3 perlakuan dan 3 ulangan. Perlakuan meliputi penggunaan rumput laut sebanyak 800 gram (P8), 400 gram (P4) dan tanpa rumput laut (Kontrol). Uji tantang dilakukan selama 10 hari dengan konsentrasi bakteri 106 cfu/mL/ekor pada 10 udang di akuarium berisi air laut 100 liter. Hasil penelitian menunjukkan bahwa polikultur rumput laut dengan udang vaname tidak dapat mempertahankan kelangsungan hidup udang secara signifikan namun dapat menekan populasi bakteri V. harveyi di perairan. Kelangsungan hidup udang berturut-turut dari kontrol, P4 dan P8 adalah 60.0%, 73.3%, 76.7%. Jumlah populasi bakteri pada perlakuan lebih rendah dibandingkan dengan kontrol pada hari ke-10 pasca penebaran rumput laut sampai dengan uji tantang. Penggunaan rumput laut juga dapat mempercepat recovery time (masa sembuh) udang dari infeksi bakteri diamati pada gejala klinis yang kembali normal pada hari ke-9 pasca uji tantang. Total hemosit (THC) teramati lebih baik pada udang yang dipelihara dengan rumput laut hari ke-10 pasca uji tantang dan diferensial hemosit (DHC) lebih baik pada hari ke-5 pasca uji tantang. Penggunaan rumput laut pada polikultur udang vaname berpotensi meningkatkan status kesehatan udang.

Effect of montmorillonite Clay in partial treatment of Sea water

With increase in population day by day all over the world, it is not easy to allocate water for everyone of them through ground water. Now providing water of good quality had been under threat, which made us to turn our view to look on alternative to groundwater like treating sea water. There are many methods to treat seawater mostly which are expensive by cost and complex in operation and maintenance. This research proposes a mechanism of using montmorillionite clay, a naturally easy available material for treating the seawater partially to meet up the as per IS standards by reducing the seawater chemical characteristics. Clay minerals have been appreciated for their nature of adsorption and cation exchange. Experiment was conducted with standard one litre of seawater by varying the montmorillionite clay and the detention time through precipitation aided by sorption and cation exchange. The major parameter analyzed were pH, Total Dissolved Solids (TDS), Chloride (Cl) and Sodium (Na). It was found that the optimum clay of 60 g at a detention time 40 min gives us a better result of removing 89.83 % TDS, 96.62 % of Chloride and 98 % of Sodium. The final distillate was found to be worth of using for industries, irrigation and domestic purpose other than drinking.

Monitoring dan Mitigasi Gas H2s Limbah Organik Tambak Intensif dengan Menggunakan Biomarker Sederhana

Monitoring dan mitigasi bahan limbah organik menjadi hal penting untuk dilakukan dalam menjaga kelestarian lingkungan perairan. Penelitian ini bertujuan untuk menganalisis gas hydrogen sulfide (H2S) yang terkandung di air limbah dan indeks kondisi kerang sebagai biomarker. Penelitian ini dilakukan dengan menggunakan metode rancangan faktorial yaitu sebanyak 10 kerang hijau yang berukuran panjang kurang lebih 6 cm dimasukkan ke dalam akuarium yang berisi 5 liter air laut yang telah dikontaminasi dengan limbah organik yang bersumber dari tambak supra intensif sesuai dengan seri konsentrasi perlakuan yaitu; 50%, 35%, 15% dan 0 (kontrol) limbah orgnik. Pemaparan dilakukan selama 96 jam. Untuk keperluan data indeks kondisi dilakukan pengukuran morfometri kerang dan pengeringan daging kerang dengan suhu 800C selama 24 jam. Hasil penelitian menunjukkan bahwa terdapat perbedaan signifikan (p<0.05) penurunan hydrogen sulfide pada air media pemaparan kerang serta perbedaan indeks kondisi kerang berdasarkan seri konsentrasi perlakuan.

Close-up observations on the spawning behavior of a captive Japanese flying squid (Todarodes pacificus)

The spawning behavior of a Japanese flying squid (Todarodes pacificus) is described based on up-close observation of a captive female. The squid was first transferred from a 10-ton tank to a polystyrene plastic box containing 45 liters of seawater. About one hour later, the mantle-contraction rate increased rapidly, followed by a brief convulsion of the mantle and arms and a whitening of the body. The mantle contractions become shallow and rapid, and several seconds later, semitransparent jelly presumably from the nidamental glands emerged from the funnel and passed between the ventral pair of arms. Approximately 90 seconds after the egg mass first emerged, the female began ejecting oocytes through the funnel into the egg mass using rapid, powerful mantle contractions. Soon after the oocytes were ejected, translucent strands (presumably sperm) emanated from the buccal membrane. The female continued to eject oocytes for approximately two minutes, after which the mantle convulsed, and the mantle-contraction rate decreased slowly for about one minute until the contractions stopped. The squid died soon afterwards.

Replacement of fishmeal with soybean meal for the diet of seabass, Lates calcarifer

Fishmeal is one of the essential raw materials in the fish diet, and this material is expensive and rarely available in the rural area. Therefore, the present study aimed to explore the possibility to replace the fishmeal with the soybean meal in the diet of Asian seabassLatescalcarifer. The study was conducted from November 2018 to January 2019 at Center for Brackish Water Aquaculture in Ujung Batee, Aceh Besar District, Indonesia. The completely randomized experimental design method was used in this study with six treatments and four replications. The tested treatment was the replacement proportion of fish meal with the soybean meal in the diet, namely: 0%, 20%, 40%, 60%, 80%, and 100%. The experimental fish were stocked at one fish per liter of seawater. The fish were fed on the experimental diet at feeding level of 10% body weight two times a day. The results showed that the proportion of the soybean meal in the diet gave the significant effect on the weight gain, specific growth rate, feeding conversion ratio and feed efficiency (P<0.05), but did not provide the considerable impact on the survival rate (P>0.05). In conclusion that approximately 40% of the fish meal can be replaced with soybean meal for Asian seabass diet.

The carbonic anhydrase activity of sinking and suspended particles in the North Pacific Ocean

AbstractThe enzyme carbonic anhydrase (CA) is crucial to many physiological processes involving CO2, from photosynthesis and respiration, to calcification and CaCO3 dissolution. We present new measurements of CA activity along a North Pacific transect, on samples from in situ pumps, sediment traps, discreet plankton samples from the ship's underway seawater line, plankton tows, and surface sediment samples from multicores. CA activity is highest in the surface ocean and decreases with depth, both in suspended and sinking particles. Subpolar gyre surface particles exhibit 10× higher CA activity per liter of seawater compared to subtropical gyre surface particles. Activity persists to 4700 m in the subpolar gyre, but only to 1000 m in the subtropics. All sinking CA activity normalized to particulate organic carbon (POC) follows a single relationship (CA/POC = 1.9 ± 0.2 × 10−7 mol mol−1). This relationship is consistent with CA/POC values in subpolar plankton tow material, suspended particles, and core top sediments. We hypothesize that most subpolar CA activity is associated with rapidly sinking diatom blooms, consistent with a large mat of diatomaceous material identified on the seafloor. Compared to the basin‐wide sinking CA/POC relationship, a lower subtropical CA/POC suggests that the inventory of subtropical biomass is different in composition from exported material. Pteropods also demonstrate substantial CA activity. Scaled to the volume within pteropod shells, first‐order CO2 hydration rate constants are elevated ≥ 1000× above background. This kinetic enhancement is large enough to catalyze carbonate dissolution within microenvironments, providing observational evidence for CA‐catalyzed, respiration‐driven CaCO3 dissolution in the shallow North Pacific.