Atlantic Ocean total

Northern Hemisphere, 1973-78, Atlantic Ocean, total chlordanes (0.009-0.084) 3... 

Local conditions may modify this profoundly in special areas. In the Arctic and Antarctic, and where there is dilution by large rivers, the salinity may be considerably less, and it may vary greatly according to season. Salinity is well below normal in the Baltic, and may fall nearly to zero at the head of the Gulf of Bothnia. In enclosed seas like the Mediterranean, Black Sea and Red Sea, on the other hand, where there is rapid evaporation, salinity may reach 40 parts per thousand. The total salt content of the inland Dead Sea is 260 g/kg compared to 37 g/kg for the Atlantic Ocean. 

Figure 3. Time series of nitrate (Slagle and Heimerdinger 1991) and dissolved, particulate, and total in surface water at 47°N, 20°W (Atlantic Ocean) in April-May 1989. activity calculated as 0.0686 salinity (Chen et al. 1986). The production of biogenic particles during the bloom enhances the scavenging of Th, resulting in growing disequilibrium with time due to sinking of particles.

The concentrations of DOC in major rivers typically range from 250 to 750 pM, and concentrations in the surface ocean range from 60 to 90 J.M (Table I). Most of the river data compiled in Table I are from the Amazon River system (Hedges et al., 1994, 2000), the Parana River system (Depetris and Kempe, 1993), and the Mississippi River (Benner and Opsahl, 2001). The seawater data are from surface water samples collected in the Pacific and Atlantic Oceans (see Table I for references). Total hydrolyzable neutral sugars (glucose, galactose, mannose, xylose, fucose, rhamnose, and arabinose) account for about 1-2% of river DOC and 2-6% of ocean DOC, indicating... 

Nixon et al. (1996) have compiled N and P data for many of the watersheds and estuaries feeding the North Atlantic Ocean. In many of the watersheds of eastern North America, the input of N from anthropogenic atmospheric supply and sewage is a considerable fraction of the total input. This is not the case for the Amazon shelf, where atmospheric and sewage inputs are small relative to riverine input and upwelling. For the embayments and estuaries of the North Atlantic, Nixon et al. (1996) observed a significant correlation between %P exported and the mean freshwater replacement time. During the AmasSeds cruises the freshwater... 

Only occasionally has the N content of solid phase extracts been reported. At a site in the Atlantic Ocean the carbon to nitrogen ratio (C N) of XAD 8 and XAD 2 extracts fell in the range of 40-57 (57 0.9 and 41.1 3.3, respectively DrufFel et ai, 1992). In contrast, at the same site XAD 4, when used as the second resin in series with XAD 8 or XAD 2, extracted compounds with lower C N ratios - 19—24 (21.0 2.4). These values are only slighdy higher than ratios reported for total DOM (see below). McKnight and Aiken (1998) reported a C N value of 37 for DOM extracted by XAD 8 at one site in the Pacific Ocean at other sites in the N. Pacific Ocean XAD 2 was found to extract DOM with a C N ratio between 32 and 46.5 (Druffel et al, 1992 Meyers-Schulte and Hedges, 1986). Bronk (2002, Table III) compiled various literature values and arrived at an average C N ratio of 32.8 19.5 for total humic substances isolated from a variety of aqueous environments (see McCarthy and Bronk, this volume). 

Not aU field evidence supports the limitation of Trichodesmium diazotrophy by Fe. Both Karl et al. (1997) and Sanudo-Wifriehny et al. (2001) observed that median Fe concentrations <1 nM Fe did not seem to hmit N2 fixation in field collected samples in the subtropical North Pacific Ocean and the Central Adantic. It has been observed that there is no close correlation between total dissolved Fe and Trichodesmium abundance in the North Atlantic Ocean when only open ocean stations are considered, and little difference between total Fe concentrations where Trichodesmium is abundant and where it is scarce (Tyrrell et al., 2003). Moisander et al. (2003) noticed that in the Baltic Sea, Fe addition did not show a significant impact on N2 fixation or biomass production by three other genera of N2-fixing cyanobacteria. 

Based on data from field campaigns in the Arabian Sea and tropical North Atlantic Ocean, Johansen et al. (1999, 2000) also suggest evidence for chlorine release processes other than acid displacement. This conclusion was made based on discrepancies in measured total anion and cation charges. Release of chlorine in the form of a reactive species may not be replaced by a detectable ion (e.g., 003 ) and this charge difference might, therefore, be used as a measirre for nonacid displacement release processes for chlorine. 

Prior to the above-related revelations about former Soviet disposals of radioactive wastes in the marine environment, more than 98% of packaged low-level radioactive material disposed of in the oceans was believed to be dumped at deep sites in the North Atlantic Ocean. 92% of the total activity was dumped in the eastern basin. While, in general, 98% of the total radioactivity disposed of comprised beta-gamma emitters, small quantities of alpha-emitting nuclides were also included. At the two main sites in... 

Figure 15.7. Stoichiometric correlations among nitrate, phosphate, oxygen, sulfide, and carbon. The correlations can be explained by the stoichiometry of reactions such as equation 3 concentrations are in micromolar, (a) Correlation between nitrate nitrogen and phosphate phosphoms corrected for salt error in waters of the western Atlantic, (b) Correlation between nitrate nitrogen and apparent oxygen utilization in same samples. The points falling off the line are for data from samples above 1000 m (Redfield, 1934, p. 177). (c) Correlation between nitrate nitrogen and carbonate carbon in waters of the western Atlantic, (d) Relation of sulfide sulfur and total carbonate carbon in waters of the Black Sea. Numbers indicate depth of samples. Slope of line corresponds to AS /AC = 0.36. (From data of Skopintsev et al., 1958, as quoted in Redfield et al., 1966.) (e) Correlation of the concentration of nitrogen to phosphate in the Atlantic Ocean (GEOSECS data). The slope through all the data yields an N/P ratio close to 16.

In our previous investigations of the amounts and distribution of mercury in the surface waters of the northwest Atlantic Ocean, we found a mean total mercury concentration of 7 ng/1. and a range of 6-11 ng/1. (26). Also, we found in open ocean surface waters no significant difference between the mercury concentrations measured directly in pre-acidified seawater ( reactive mercury) and the total mercury determination in the organic free samples. In the work shown in Table II, we also found no significant difference between the reactive mercury determination and the total mercury measurement, which was carried out in approximately one third of the samples. The total mercury measurements appear in the square brackets for the results tabulated in Table II. 

Analyses were made on a number of samples of seawater and marine sediments which appear essentially uncontaminated by any artificial radionuclides and which can indicate the total analytical blank found in these measurements. The sediment samples were deep sections of gravity cores from the deep ocean (sections well below the level of the least detectable fallout nuclides), and the water samples were from deep in the Southern Atlantic Ocean. These data may be compared with the analytical data in Figure 1 and Tables V and VI to demonstrate that the analytical blanks are extremely low compared with the nuclide concen-... 

Salinity-normalized (S = 35) total alkalinity. Ay n> versus salinity-normalized dissolved inorganic carbon, DICn, for the world s ocean. Data are for the deep ocean at depths >2.5 km except for the section labeled North Atlantic Shallow," which is 100-1000 m in the North Atlantic Ocean. Lines indicate different DICn At.n ratios. (See Plate 2.)... 

From Mc2Hg data in surface sea water samples and in the corresponding marine atmosphere, a first estimation of the transfer of this compound from the Southern Ocean, the Arctic Ocean and the Atlantic Ocean was carried out by equation (1) (see Table 7.7) (45). This estimate was calculated under the questionable assumptions that the measured data were representative for the whole area and that no seasonal variation occurs. The great uncertainty in such calculations can also be inferred by the great variability in the data for the total biogenic Hg emission from all oceans, which range from 0.6 10 to 7700 10 g yr (66, 67). However, the calculated input of more than 0.2 10 g yr of Hg as Mc2Hg from each of the polar oceans is more than 10% of the total emission of this heavy metal species from the Atlantic Ocean. In addition, more recent data from Lindqvist et al. and... 

The calculations (Howarth, 1996) showed that for the North Atlantic Ocean watershed the percentage of sewage and wastewaters to total nitrogen input varies among the regions, from a high of 34% in the North Sea region to virtually none in the Amazon basin (Table 6). 

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