Nansen Bottle Research Articles

On the Consistency of the Bottle and CTD Profile Data

Abstract Nansen bottle casts served as the main oceanographic instrumentation type for more than a century since the establishing of the technique in the late 1890s. Between the end of the 1960s and the end of the 1990s Nansen cast technique has been gradually replaced by electronic sensor profilers (CTD). Both instrumentation types are considered as the most accurate among other oceanographic instruments and are often used as the unbiased reference. We conducted a comprehensive investigation of the consistency of the temperature data from Nansen casts and CTD profilers analyzing the quasi-collocated bottle and CTD data between the 1960s and the 1990s when both instrumentation types overlap. We found that Nansen casts tend to overestimate the sample depth with reversing mercury-in-glass thermometer temperatures being on average slightly lower compared to CTD data. Respectively, depth and temperature corrections are provided. Further, we estimated the ocean heat content changes between 1955 and 1990 using (along with all other instrumentation types) corrected and uncorrected Nansen cast data. These calculations show that for the upper 2 km layer the global average warming trend for this time period increases from 0.20 ± 0.05 W m−2 for the uncorrected data to 0.28 ± 0.06 W m−2 for the corrected data at the 90% confidence level. Finally, we suggest that the Nansen bottle cast profiles be put into a separate instrumentation group within the World Ocean Database.

The Optimization of Sulphide Oxidizing Bacteria (SOB) for Oil Corrosivity Reduction at Indramayu Coast, The Northern Coastal Area of West Java

Highlight Research First NR-SOB from Indramayu coast was successfully isolated and identified. Bactrerial characterization morphologically and biochemically, foster with in situ hybridization confirm the isolate was Thiobacillus denitrificans, and Arcobacter sp. Both isolate, Thiobacillus denitrificans and Arcobacter sp., were able to grow in sulphide rich environment in the presence of essential nutrient Thiobacillus denitrificans and Arcobacter sp. exhibit an outstanding sulphide oxidation ability up to 100% in the presence of nitrate. Abstract Crude oil production triggers the formation of hydrogen sulphide, also known as souring, which is extremely toxic and corrosive to the environment. It additionally give an adverse consequence to aquatic, terrestrial, and human existence. Studies of hydrogen sulphide reduction in sediments polluted by crude oil have been carried out recently to investigate the capability of indigenous Nitrate-Reducing Sulphide Oxidising Bacteria, hereinafter referred to as NR-SOB, as bioremediation agents. The experiments utilised hydrogen sulphide with 200 µM concentration combined with NO3 with different concentrations of 100 µM, 200 µM, and 300 µM. Measurements of the hydrogen sulfide concentrations were observed up to 48 hours within the experimental period. The SOB used in this study were taken from Balongan Bay at Indramayu coast using Nansen bottle to carry out water sample. The sulphide-oxidising ability of SOB was then evaluated at room temperature in control environment. Methylene blue method was applied to monitor the sulphide concentration. The results showed a complete removal of hydrogen sulphide concentrations in 48 hours accompanied with gradual drops of nitrate in all experiment series. Sulphide oxidation rate was detected to appear between 6.8 and 10.2 fmol/cell/hour. Measurements of cell abundance after 48 hours showed 6.2 x 105, 7.5 X 105, and 8.2 X 105 cell/ml from Experiments I, II, and III respectively. Using MSS selective medium, the bacteria were identified as Thiobacillus denitrificans and Arcobacter sp. Overall, the isolated NR-SOB from the coast of Balongan Bay, Indramayu proves to be a promising candidate for sulphide controls and mitigation.

Determination of total petroleum hydrocarbons and selected heavy metal (Pb, CO, V, Ni) concentration levels in surficial sediments of the Arvand River Estuary and their impact on benthic macroinvertebrates assemblages

ABSTRACT In the current study, the determination of total petroleum hydrocarbons (TPHs) and selected heavy metal (Pb, Co, V, Ni) concentration levels in surficial sediments of the Arvand River and their impacts on benthic invertebrate assemblages are investigated. For this purpose, a total of 100 surface sediment samples from 10 stations were collected for TPHs, heavy metals, macroinvertebrates, TOM, and grain size measurements using a Van-Veen grab sampler during winter 2018. A Horiba U10 multiparameter probe was used at each station for the in-situ measurement of environmental variables of water samples close to river bottom using a Nansen bottle sampler. Sediment quality guidelines along with Pearson’s correlation analysis and calculated diversity indices revealed that Arvand River Estuary (ARE) is threatened by contamination, especially with respect to Ni, Pb, and TPHs. The relatively high concentrations of Ni in most stations and Pb in some stations comparing to guidelines and other regions can be related to industrial activities as well as passing several ships and boats in the region. Shannon–Wiener diversity values recorded in the present study ranged between 0 and 2.01 indicating heavy to moderate pollution status in ARE. Altogether, the present study findings could be useful as the baseline for future research and better management for reducing contaminant levels.

Influence of some physico-chemical variables on wild fish richness beneath sea-cage fish farms in the Aegean Sea, Turkey

AbstractThis study aims to determine the relationship between physico-chemical variables on a seasonal basis and wild fish assemblages beneath sea-cage fish farms. Assemblages of wild fish were counted monthly on two separate days at each of six fish farms between August 2015 and July 2017, by six rapid visual counts (RVC) in 5 minutes with scuba by two divers. Seawater samples were simultaneously taken by a Nansen bottle during the RVC from the fish farm barge. SST (°C), salinity (ppm), dissolved oxygen (mg l−1) and pH were measured by YSI multiparameter, while Secchi disk was also used for light transmittance. Wild fish species richness went up with increasing temperature and salinity in the Izmir region, however, this stopped at about 26°C and about 39 ppm. Wild fish richness increased when the DO was at a level of 7 mg l−1 and the pH at about 7.9 in Izmir. Between 10 and 20 m, light transmittance showed greater wild fish species richness in Izmir region. In contrast, the wild fish species richness of the Muğla region fluctuated more. In terms of wild fish species richness, these fluctuations increased with salinity and DO, while they decreased with SST, pH and light transmittance. However, the range of variation of the recorded physico-chemical variables is rather narrow. The results of the correlation matrix indicate that the relationship between wild fish species richness and pH and SST was statistically significant in Izmir region (P < 0.05).

Correction for Systematic Errors in the Global Dataset of Temperature Profiles from Mechanical Bathythermographs

AbstractA homogeneous, consistent, high-quality in situ temperature dataset covering some decades in time is crucial for the detection of climate changes in the ocean. For the period from 1940 to the present, this study investigates the data quality of temperature profiles from mechanical bathythermographs (MBT) by comparing these data with reference data obtained from Nansen bottle casts and conductivity–temperature–depth (CTD) profilers. This comparison reveals significant systematic errors in MBT measurements. The MBT bias is as large as 0.2°C before 1980 on the global average and reduces to less than 0.1°C after 1980. A new empirical correction scheme for MBT data is derived, where the MBT correction is country, depth, and time dependent. Comparison of the new MBT correction scheme with three schemes proposed earlier in the literature suggests a better performance of the new schemes. The reduction of the biases increases the homogeneity of the global ocean database being mostly important for climate change–related studies, such as the improved estimation of the ocean heat content changes.

MICROALGAE FROM THE COASTAL WATERS OF TYULENY ISLAND IN THE CASPIAN SEA

Aim. In this work, we set out to study the composition of a phytoplankton community in an important fishery area, the coastal water area of Tyuleny Island in the Caspian Sea.Methods. We present the results of seasonal observations (2016) on the state of phytoplankton in the coastal waters of Tyuleny Island in the Caspian Sea. In total, 120 phytoplankton samples were collected at four stations from the water surface layer (May–October) using the Nansen bottle and subsequent fixation by Lugolʹs solution. Sedimentation and concentration were carried out using standard procedures. The samples were processed in the Nageotte chamber with a volume of 0.1 ml under a light microscope.Results. According to the research results (2016), 103 species and varieties of microalgae were found in the phytoplankton samples collected from the water area of Tyuleny Island. The microalgae were represented by four divisions: Bacillariophyta – 49 species, Cyano‐ phyta – 24 species, Chlorophyta – 23 species and Pyrrophyta – 7 species. The greatest species diversity of phytoplankton in the studied water area was noted during the autumn period (61 spe‐ cies). In general, phytoplankton was found to be distributed homogeneously throughout the coastal area of the island, with the biomass concentration not reaching 1 g/m3.Conclusion. In 2016, favorable hydrological and hydrochemical conditions for the development of microalgae were observed. The desalinated water around Tyuleny Island, which is well warmed in the summer and does not freeze in the winter, contributed to the development of rich flora. Although bi‐ omass values were not high due to the prevalence of small‐celled microalgae in phytoplankton, in general, it should have a positive effect on the development of subsequent links in a trophic chain, as well as promote an increase in the productivity of waters of the Northern Caspian Sea.

Study on existence of the fisheries resources abundance by using environmental deoxyribonucleic acid (e-DNA) approach at fishing grounds in the Sulawesi Sea, Indonesia

Here, we report the results of our preliminary study on deep sea eDNA at fishing ground to approach the fisheries resources abundance at Sulawesi sea by using deep-sea water sampling collected from 10 sites ranging from 110m-200m in depth at front side of the International Coelacanth Research Center and Museum Base at Lolak Waters and Manado Bay North of Sulawesi using Nansen Bottle Sampler (1500 cc). The collected waters were filtered using Power Water Sterivex DNA Isolation Kits and preserved with the DNAiso Reagent then transported to Center for Strategy Research Project, University of the Ryukyus, Okinawa Japan where eDNA analyses were conducted. Our results revealed that the concentrations of eDNA has a good quality were measured with a NanoDrop Lite spectrophotometer, indicating eDNA was successfully extracted. Therefore, by using universal primers for eDNA, MiFish-U-F/R for the 1st-PCR (mt-12S amplification) and 2nd-PCR (tag-indexing) for library preparation to accommodate sequence variations and show that intense signal of MiFish eDNA amplification. Using a high-throughput Illumina MiSeq platform for sequencing analyses, we detected eDNA from 40 fish’s species with dominantly by Caranx sexfasciatus, Encrasicholina punctifer.

Seasonal variations of plankton structure as bioindicators in Zayandehrud Dam Lake, Iran

Abstract Zayandehrud Dam Lake located in Isfahan province is the largest lake in central Iran. In this study, the plankton communities including phytoplankton and zooplankton were studied as bioindicator organisms for assessment of water quality in the Zayandehrud Dam Lake. The water and phytoplankton organisms were collected from four stations at different seasons during 2014 by using a Nansen bottle sampler. The zooplankton samples were collected with a plankton net (mesh size = 50 µm). The phytoplankton community was composed of Bacillariophyceae, Cyanophyceae, Euglenophyceae, Dinophyceae and Chrysophyceae. The zooplankton community viz; Cladocera, Rotifera and Copepoda were found to have a density range of 13–155, 21–141 and 11–93 (ind. m−3), respectively. In general, phytoplankton and zooplankton communities, especially the presence of genera such as Cyclotella, Dynobrion, Bosmina and Daphnia (as indices of oligotrophic lakes) and also absence of Microsystis, Brachionus and Lecane are seen as important indices of eutrophic lakes. It could be concluded that the Zayandehrud Dam Lake can be classified as a healthy water body.

Characteristic sediment and water column chlorophyll-a in the sea cucumber’s Paracaudina sp. habitat on the Kenjeran Water, Surabaya

The study of characteristic sediment and water column chlorophyll-a has an important role in the sea cucumber habitat. Sediment chlorophyll-a represents a productivity primer for the benthic community. This research has a purpose to investigate characteristic sediment and water column chlorophyll-a on the Kenjeran water, Surabaya. Sediment samples were collected by the ekman grab for analysis, grain size and nutrient. The sample for sediment chlorophyll-a was taken by core sampler. The water samples were taken with Nansen Bottles. According to the research result, the values of sediment chlorophyll-a at station 10, 11 and 12 were higher than the other stations. In contrast, the value of chlorophyll-a in the column water had almost the same value for each station. The sediment chlorophyll-a value on clay and silt sediment type was higher than the fine sand and coarse sediment type. The suitable habitat characteristic for Paracaudina sp. was clay and silt sediment with sediment chlorophyll concentration ranging from 347.82 mg·m-2 to 1135.52 mg·m-2.

The Influences of Physical and Chemical Factors to Coral Reef Ecosystem on Coastal Waters Village Eri, Outer Ambon Bay

This research conducted in coastal waters of Eri, Outer Ambon Bay on July 2011 to analysis the influences of physical-chemical factors of coral reef ecosystem on coastal waters of Eri. Physical-chemical factors of coastal waters measured used CTD. The result measurement data of Current meter and CTD carried out by computer use software equipment. Data processing and graph analyze use the software of Microsoft Excel 2003 and Golden Software Surfer 9. The sample of dissolved oxygen, phosphate and nitrate taken with Nansen Bottle. Dissolved oxygen determined by pursuant to titration Winkler. Rate of phosphate and nitrate analysis by Strikland and Parsons method (1968). The enumeration sample of dissolved oxygen, rate of phosphate and nitrate conducted in laboratory of LIPI Ambon. From research known that the temperature in coast of Eri on July range from 25.9°C – 27.3°C. The salinity ranges from 33.5 ppt – 34.2 ppt. The current sea in coastal water of Eri moves follow the current install pattern and withdraw in Ambon Bay. Others influenced by wave which is resulted by monsoon. The turbidity around coast more predominated by inorganic material in the form of refinement sand which suspend effect of current in coast. Phosphate rate detected range from 0.00489 – 0.0079 ppm and nitrate rate range from 0.0390 – 0.0671 ppm. While gyration assess of dissolve oxygen is lowering with the value 1.99 ppm until 3.38 ppm. All of physical and chemical factor was good to influenced coral reef ecosystem on coastal water village Eri.

IBAMar Database: Four Decades of Sampling on the Western Mediterranean Sea

IBAMar is a regional database that puts together all the physical and biochemical data provided by multiparametric probes and water sample analysis taken during the cruises managed by the Balearic Oceanographic Center of the Instituto Espanol de Oceanografia (COB-IEO) during the last four decades. Initially, it integrated data from hydrographic profiles obtained from CTDs (conductivity, temperature, depth) equipped with several sensors, but it has been recently extended to incorporate data obtained with hydrocasts using oceanographic Niskin or Nansen bottles. The result is an extensive regional resource database that includies physical hydrographic data such as temperature (T), salinity (S), dissolved oxygen (DO), fluorescence, and turbidity, as well as biochemical data, specifically dissolved inorganic nutrients (phosphate, nitrate, nitrite, and silicate) and chlorophyll-a. Different technologies and methodologies were used by independent teams during the four decades of data sampling. However in the IBAMar database, data have been reprocessed using the same protocols and a standard quality control (QC) methodology has been applied to each variable. The result is a homogeneous and quality-controlled data. IBAMar database at standard levels is freely available for exploration and download from http://www.ba.ieo.es/ibamar/.

Effect of environmental factors on the abundance of decapod crustaceans from soft bottoms off southeastern Brazil

This study investigated the importance of variations in environmental factors affecting the abundance patterns of decapods on the southeastern Brazilian coast. Sampling was carried out monthly from January 1998 through December 1999 in Ubatumirim and Mar Virado, Ubatuba region, using a commercial shrimp fishing boat equipped with double-rig nets. Six areas adjacent to rocky shores were chosen. Bottom-water samples were collected using a Nansen bottle, to measure the temperature and salinity. Sediment samples were also obtained by means of a Van Veen grab, for determination of texture and organic-matter content. The association of environmental factors with species abundance was evaluated by Canonical Correspondence Analysis (α = 0.05). Forty-one species of Decapoda were used in the multivariate analysis. The analysis indicated that sediment texture (phi) and bottom temperature were the main factors correlated (p < 0.05) with the spatial and temporal abundance of the species. Considering the study region as faunal transition zone, including a mixture of species of both tropical and subantarctic origin, the species responded differently to environmental factors, mainly temperature. It is conceivable that the decapods adjust their distribution according to their intrinsic physiological limitations, possibly as a result of the available resources.

BOX MODEL AIR TAWAR, SALINITAS DAN ZAT HARA DI DELTA MAHAKAM KALIMANTAN TIMUR

Box Model of Freshwater, Salinity and Nutrient in the Delta Mahakam East Kalimantan. Research has been conducted in the southern part of the Mahakam Delta, East Kalimantan. Method of measuring temperature, salinity, light transmission and turbidity by using CTD model 603 SBE and current measurement and bathymetry by using ADCP model RDI. Measurement parameters on the nutrient chemistry are based of water samples taken using Nansen bottles from two depths. The purpose of this study to determine the mechanism of freshwater, salinity and nutrient transport from the land of the Mahakam River which interact with seawater by using box models. The results illustrate that the vertical distribution of salinity in the Mahakam Delta has obtained a high stratification, where the freshwater salinity 12.30 psu at the surface of a river flowing toward the sea, and seawater of high salinity 30.07 psu flowing in the direction river under the surface that are separated by a layer of mixture. Freshwater budget of the sea (VSurf) obtained for 0,0306 x 109 m3 day-1, and the sea water salinity budget is going into the bottom layer system (VDeep.SOcn-d) obtained for 20,727 x 109 psu day-1. While time dilution (τSyst) obtained for 0.245 day-1 or 5.87 hours. Nutrient budget in the surface layer obtained by the system is autotrophic while in layers near the bottom tend to be heterotrophic. Keywords: box model, freshwater, Mahakam Delta, nutrient, salinity

Characterization of phytoplankton biodiversity in tropical shipwrecks off the coast of Pernambuco, Brazil

The phytoplankton community was studied around two artificial reefs (shipwrecks Servemar-X and Servemar-I), located off the coast of Pernambuco, northeastern Brazil, aiming to identify and thus, better describe these environments. Water samples were collected with Nansen bottle at three depths (surface, mid-column and bottom) for chlorophyll a analysis and salinity; temperature and water transparency were also measured. To collect phytoplankton samples, a diver using SCUBA equipment carried out phytoplankton hauls with a 20 µm net around the shipwrecks, about 1.5 m from the bottom for approximatly 3 minutes. Chlorophyll a concentrations at the bottom varied between 0.61 and 5.97 mg.m-3, with an average that indicates a mesotrophic environment. Temperature and salinity registered small seasonal variation, while water transparency showed a seasonal spatial pattern positively related to Chl-a rates. As regards the phytoplankton community, diatoms were the most representative group in the samples, followed by dinoflagellates, and among the species, the cyanobacteria Trichodesmium thiebautii Gomont ex Gomont prevailed quantitatively. The ecological importance of these ecosystems was confirmed by the high diversity and evenness indexes, with the influence of coastal waters playing an essential role in phytoplankton structure and diversity.

The general circulation in the Mediterranean Sea: a climatological approach

A significant amount of hydrographic data has been collected in the Mediterranean during this century, providing the basic ingredients needed to construct a climatological picture of the general circulation. A pooled hydrographic data set has been prepared, which currently contains over 100,000 station profiles (CTD, Nansen bottle, XBT and MBT) taken in the Eastern and Western Mediterranean Sea between 1900 and 1993. Climatological analyses of temperature and salinity data are performed at seasonal and monthly scales, using a variational method and a finite element numerical technique. The variational formulation had been demonstrated to be equivalent to objective analysis, and a hybridation of the statistical and variational methods allows to compute error fields associated to the climatology. The free parameters of the scheme are determined using a cross-validation algorithm to extract the best seasonal statistics from the observed data sets. Compared to earlier climatologies, the recent analyses show significant improvements with respect to the regional scales of the general circulation gyres. In addition, several features of the general circulation are described with a better accuracy. Finally, the barotropic equations (external mode) of a free-surface, primitive equation model are integrated in time to diagnostically adjust the sea-surface elevation to the thermohaline structures. Geostrophic velocities are then computed, integrating the thermal-wind equations with the sea-surface pressure as a reference. Results of fully prognostic, three-dimensional, primitive equation models are compared with these diagnostic computations in order to identify which features of the general circulation can be captured by observations.

Summertime thermohaline structure off the Brazil Current Region between Santos (SP) and Rio de Janeiro (RJ)

Within the scope of the MAR-14 Project, part of the Brazil-Germany Bilateral Agreement in Marine Sciences, an oceanographic survey aboard the R/V Victor Hensen was carried out in Brazilian coastal waters between Santos (23o56'S) and Rio de Janeiro (22o54'S), from January 15 to January 22,1991. In this article we report results of preliminary analyses of the hydrographic data collected with CTD, STD, Nansen bottles and XBT's. These preliminary results show intense stratification in the first 200 m depth, and the penetration of the Brazil Current deep into the continental shelf region. Two eddy-like features were detected. The first one, anticyclonic, was located in the northern part of the domain and confined to the uppermost 200 m. The second, a cyclonic vortex, was found a little to the southwest below 200 m and extending downwards to about 800 m depth. Water mass analyses based on T-S diagrams suggest that the interface between the South Atlantic Central Water (SACW) and the Antarctic Intermediate Water (AIW) is located at about 500 m depth. One important aspect of this study is that this was the first time a high resolution survey with a CTD probe was realized along the eastern Brasilian Coast, south of Cabo Frio.

Summertime thermohaline structure off the Brazil Current Region between Santos (SP) and Rio de Janeiro (RJ)

Within the scope of the MAR-14 Project, part of the Brazil-Germany Bilateral Agreement in Marine Sciences, an oceanographic survey aboard the R/V Victor Hensen was carried out in Brazilian coastal waters between Santos (23º56'S) and Rio de Janeiro (22º54'S), from January 15 to January 22,1991. In this article we report results of preliminary analyses of the hydrographic data collected with CTD, STD, Nansen bottles and XBT's. These preliminary results show intense stratification in the first 200 m depth, and the penetration of the Brazil Current deep into the continental shelf region. Two eddy-like features were detected. The first one, anticyclonic, was located in the northern part of the domain and confined to the uppermost 200 m. The second, a cyclonic vortex, was found a little to the southwest below 200 m and extending downwards to about 800 m depth. Water mass analyses based on T-S diagrams suggest that the interface between the South Atlantic Central Water (SACW) and the Antarctic Intermediate Water (AIW) is located at about 500 m depth. One important aspect of this study is that this was the first time a high resolution survey with a CTD probe was realized along the eastern Brasilian Coast, south of Cabo Frio.

Circulation in the Timor Sea

In October 1987 and March 1988, measurements were taken across the Sahul shelf and the southwestern end of the Timor Strait to the edge of Indonesian waters. The shipboard instrumentation comprised a conductivity‐temperature‐depth (CTD) rosette, an acoustic Doppler current profiler (ADCP) and a Pegasus dropsonde. Complementary data came from satellite‐tracked drifters, continental shelf moorings, and a Nansen bottle survey in 1976. Pegasus and ADCP measurements in the strait suggested a total transport of about 7 Sv toward the Indian Ocean, with about half of this in the upper 350 m. However, transports may at times be higher, because a drifter in July 1983 revealed speeds of l m s−1 in the strait, twice those measured on the surveys. Data from moored current meters implied a transport on the shelf of roughly 1 Sv, except in the autumn transition of the monsoon in 1985 when it exceeded 3 Sv. Water properties measured on the 1987 and 1988 surveys suggested components from the Flores and Banda seas, Indian Ocean Central Water and a high‐salinity subsurface plume from evaporation on the inner Sahul shelf.

A deep boundary current in the Arabian Basin

Recently collected CTD data are supplemented by historical Nansen bottle data to examine the circulation of bottom water in the Arabian Basin. A deep western-boundary current is observed flowing southeastward below a mid-depth zero-velocity surface along the Carlsberg Ridge. A zero-velocity surface at potential isotherm 1.7°C in chosen on the basis of water-mass properties. However, the origin of the bottom water in the Arabian Basin cannot be determined in a like manner. The bottom water could enter from the Somali Basin through the Owen Fracture Zone, or from the Central Indian Basin through passages in the Chagos-Laccadive Ridge south of the equator. Application of the Stommel-Arons framework for deep-circulation dynamics to the basin suggests that the bottom water is supplied primarily through the Owen Fracture Zone.

The loss of dissolved oxygen in Nansen bottle samples from the deep Atlantic Ocean

In the tropical and subtropical Atlantic Ocean loss of dissolved oxygen nearly always takes place within Nansen bottles between the time they close, in deep water, and the time the samples are drawn for analysis. The principal cause of this oxygen loss, in routine stations, is shown to be degassing; deep samples, rich in oxygen, are heated to above their saturation point as they are brought up through the thermocline and surface layers. Niskin bottles, which are better insulated, are immune from the fault. Examples of oxygen loss due to chemical reaction within the Nansen bottle and loss due, possibly, to bacterial respiration, are also described.