Seawater collection

The determination of lead in seawater collected from 14 stations in Guan-abara Bay gave values between 0.07 and 5.5 xg/kg. 

Imai, I., et al., Monitoring of DSP toxins in small-sized plankton fraction of seawater collected in Mutsu Bay, Japan, by ELISA method relation with toxin contamination of scallop. Mar. Pollut. Bull., 47, 1-6, 114, 2003. 

The bacteria inoculum was prepared from 0.8 pm prefiltered Antarctic seawater collected four months before the experiments at McMurdo Sound (Antarctica). These bacteria were pre-incubated in LFe (<1 nM) and HFe (+2 nM) Antarctic seawaters for at least five generations. They were grown in the dark at 2°C. 

Figure 11.13 Effects of the addition of dissolved inorganic N (NELj and NOj , 5 pM each), N-containing rainfall (collected at Morehead City, NC), iron (as EDTA-chelated and non-chelated FeCla 0.2 pM each EDTA, and the combination of NOs and EDTA-chelated FeCls) on coastal Atlantic Ocean phytoplankton communities. In situ bioassays were conducted for 5 days on seawater collected approximately 25 km SE of Beaufort, NC in the summer of 1994. Phytoplankton growth responses are reported as photosynthetic CO2 fixation and chlorophyll a accumulation. Indicates treatments were significantly (p < 0.05) from controls, using Bonferroni a posteriori comparisons of the means. See Paerl etal. (1999) for details of the experimental procedures.

Figure 2. Vacuum extraction flask for headspace seawater collection and analysis. Seawater is added to the fill line, and the flask is pressurized with zero...

Iselin cruise. On all cruises, cells for calibration were collected in nearsurface waters so that cells would have high levels of bioluminescence (34). The dinoflagellates were collected late in the afternoon by net tows, isolated by pipette into filtered seawater, collected from the same depth, and held in 10-mL pipettes with enlarged tips. After several hours in the dark, and at the time of natural darkness, they were gently introduced a few at a time into the sample chamber intake of the bathyphotometer with the pump running. Batches of the same cells were assayed in the laboratory photometer after being isolated into 3 mL of filtered seawater, held several hours in darkness, and stimulated mechanically to exhaustion. 

Table I. A Comparison of Mercury Determinations in Surface Seawater Collections from Pre-acidified Teflon Bottles and from 3-1. PVC Samplers"...

The results of this sampler study are summarized in Table I, where the value for the mercury concentration in each case is the mean mercury concentration found by triplicate analysis. The mercury concentrations found in the surface seawater collected in Teflon agree within experimental error with those for this same water after 1 hr in the PVC sampler subjected to the hydrocast procedure and sample transfer usually used. The mercury concentrations found at other depths (Table II) show little variation from the surface values. This suggests that the open samplers are not contaminated or affected signiflcantly by the hydrocast procedure. Additional details regarding this sampling study can be found in Fitzgerald and Lyons (27). 

Structurally related cerebrosides asperiamides B (198) and C (199) were obtained from A. nigerMF-16, which was isolated from seawater collected in Quanzhou Gulf, China, together with two known intermediates of aflatoxin biosynthesis, averufm and nidurufin/ ° The latter compounds displayed moderate antiviral activity against tobacco mosaic virus, while 198 and 199 were inactive. 

Oil samples were analyzed for remaining low-molecular-weight hydrocarbons by equilibrating 10-20 mL of the original or surface-collected oil with 70 mL of seawater collected outside the spill area. The oil and water were hand-shaken gently and periodically for 24 hr or more to establish equilibrium, Mercuric chloride added to water samples at time of collection prevented possible biodegradation of hydrocarbons during the oil-water equilibration. This water was analyzed by the gas-equilibration technique. 

The formation of Cu(I) In coastal waters exposed to sunlight was Investigated. Seawater collected from Blscayne Bay was scored In Che dark for 2 weeks and exposed to sunlight In round bottomed... 

The final two samples Investigated consisted of a marine fulvlc acid Isolated by XAD-2 resin absorption (14) of a bulk sample of near surface seawater collected from a site in the Gulf of Mexico (15) and also a soil fulvlc acid extracted from an horizon B podsol (16). These samples were dissolved In filtered Gulf Stream seawater and deionized (MllllQ) water respectively, with the addition of sufficient O.IM NaOH to effect dissolution of the solid soil fulvlc acid. 

Many micronutrients in seawater occur at extremely low concentrations. Accidental contamination of laboratory ware can easily alter levels of some critical elements quite profoundly. For those who might wish to repeat our experiments, scrupulous cleanliness is mandatory in all phases of the work. Our culturing studies have utilized seawater collected from a depth range of 0 to 870 m. Most experiments, however, were conducted with water from 300 m deep, collected about 5 km offshore from our laboratory headquarters... 

C. Evaporation. Seawater collected in a pond is allowed to sit and evaporate. Tidal gates, which are always closed during low tide to prevent backflow of brine, can be kept closed to prevent dilution until a certain amount of water has evaporated and the partly evaporated brine has been transferred to another pond. Alternatively, seawater can be allowed to enter the first pond along with the tides in order to keep the front-end productivity at a maximum. 

Due to its high capacity, sample preparation other than membrane filtration is not required. Furthermore, by detecting iodide via its UV absorption, matrix anions such as chloride, sulfete, and bicarbonate are not detected and thus do not interfere with iodide determination. Figure 10.53 shows the separation of iodide spiked into natural seawater collected in Half Moon Bay, CA, USA. As shown, iodide is easily determined by UV detection with a recovery of 96%. 

NaH2P04, pH 3 flow rate 0.2 mL/min detection UV (223 nm) injection volume 25 pL sample seawater collected from Half Moon Bay, CA, USA peaks bromide (1) and 19.6pg/L iodide (2). 

Most samplers used for seawater collection are adequate to obtain seawater samples for arsenic species determination we have used Niskin and Go-Flo samplers (General Ocea-nics) as well as TPN and COC samplers (Hydrobios) for sample collection and have not seen evidence of contamination resulting from any of these samplers (see also Chapter 1). 

For reliable flux data both particles and supernatants, therefore, have to be analysed. For TE analyses a 1 % solution of sodium azide in seawater (Le., a 4 1 mixture of in situ seawater, collected by GoFlo-samplers, and 5 % sodium azide stock solution in high-purity distilled water) is recommended as a preservative. 

The study test solution was tropical seawater collected appa-oximately 100 m from the shoreline of Pantai Teluk Kalong, Kemaman, Terengganu. Pantai Teluk Kalong is located near Teluk Kalong Industrial Estate (oil and gas industrial area) and Kemaman Supply Base port which is about 6.78 km from Chukai, Terengganu, Malaysia. 

Figure 7.2. The variability in EEM fluorescence for whole DOM collected from surface waters compared to ultrafiltered permeate (<1 kDa MWCO) and retentate (>1 kDa MWCO) fractions. (A-C) Susquehanna River water collected at the head of the Chesapeake Bay. (D-E) Coastal seawater collected from the Middle Atlantic Bight. The boxes and letters on each EEM contour plot refer to the fluorescent peak region designations from Table 7.1.

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