Marine Chemistry and Geochemistry (MC&G)
Permanent URI for this collection
Research in MC&G ranges from the glacial history of the Antarctic ice sheet and the formation of surface films in the upper micron of the ocean to the cycling of carbon through various ocean reservoirs, the history of ocean circulation recorded in the growth bands of coral, and the role of hydrothermal vents and seawater-rock interactions on the composition of the oceans.
Browse
Browsing Marine Chemistry and Geochemistry (MC&G) by Issue Date
Results Per Page
Sort Options
-
Technical ReportData file on amino acid distribution in calcified and uncalcified tissues of shell-forming organisms(Woods Hole Oceanographic Institution, 1966-06) Degens, Egon T. ; Spencer, Derek W.Largely for reason of limited space, scientific journals can only accept brief articles. Thus full accounts on analytical techniques, data files, and other details are frequently omitted, and pertinent information may be lost. Although this information is only of peripheral interest to the general reader, to the fellow scientist it is of vital significance. In order to serve both the specialist and the general reader, we have prepared a series of manuscripts dealing exclusively with either background information or the actual interpretation and discussion of the data. The present report is aimed chiefly at the specialist interested in calcification processes in biological systems, in molluscan ecology and phylogeny, and in amino acid analyses. It incorporates information on: (a) type, locality, and environment of sample material, (b) analytical techniques, (c) utilization of a digital computer and (d) quantitative amino acid analysis in the form of data sheets, i,e. computer printouts.
-
ThesisA study of certain trace metals in sea water using anodic stripping voltammetry(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1970-01) Fitzgerald, William F.Anodic stripping voltammetry utilizing a thin film mercury composite graphite electrode has been evaluated and applied for the direct analysis of the metals, Zn, Cu, Pb, and Cd in sea water. The electrode was observed to follow theoretical behavior for thin film electrodes and the technique was found not to be adversely affected by dissolved organic material in sea water. Good precision (ca., 5%) was obtained in both coastal and open ocean waters at the in situ concentrations of Zn, Cu, Pb, and Cd. It was shown that this method is at present most suitable for measurements of Cu, Pb, and Cd in sea water. Evidence is given suggesting that Ni may interfere with the determination of Zn through formation of an intermetallic compound, and further studies are indicated to understand this phenomenon. The anodic stripping apparatus was adapted and used conveniently on shipboard. It was demonstrated that stripping analysis could be combined with a method for the destruction of dissolved organic matter (photo-oxidation with ultra-violet radiation), and with an addification procedure to obtain measurements of trace metal speciation in sea water. An argument for the existence of Cu-aspartic acid chelates in sea water has been described theoretically and demonstrated empirically; suggesting that a significant fraction of Cu and other trace metals may be expected to be organically sequestered in sea water. A study of coastal waters employing the total method (anodic stripping-photo-oxidation-acidification) indicated the presence of a significant group of organic ligands that complex Cu (ca., 60%). It was also shown that the waters subject to gross pollution contain about 30% of the total Cu in very stable organic complexes that release Cu only when the dissolved organic matter is destroyed, and not when the pH of this sea water is adjusted to 3. An open ocean trace metal study of a thermal-front zone in the western Sargasso Sea gave data for Cu, Zn, Pb, and Cd that compared favorably with other relevant investigations. Higher free metal concentrations were observed south of the front than to the north, providing further evidence that these fronts may mark a change between southern and northern conditions in the Sargasso Sea. Data obtained from shipboard analyses using the total analytical method indicates the presence of weak organic complexes with Cu and Pb in open ocean waters.
-
Technical ReportThe West Falmouth oil spill : persistence of the pollution eight months after the accident(Woods Hole Oceanographic Institution, 1970-09) Blumer, M. ; Sass, J. ; Souza, G. ; Sanders, Howard L. ; Grassle, J. Frederick ; Hampson, George R.A spill of 650,000-700,000 liters of #2 fuel oil has contaminated the coastal areas of Buzzards Bay, Mass. The present report summarizes the results of our continuing chemical and biological study which were available at the end of May 1970, more than eight months after the accident. The effects of environmental exposure on the composition of the oil are discussed; many analytical parameters are sufficiently stable to permit continued correlation of the oil remaining in sediments and organisms with the fuel oil involved in the spill. Oil from the spill is still present in the sediments, inshore and offshore and in the shellfish. A further spread of the pollution to more distant offshore regions has occurred during midwinter; as a result, the pollution now covers a much larger area than immediately after the accident. The first stages of biological (presumably bacterial) degradation of the oil are now evident especially in the least polluted regions; however, it has depleted predominantely the straight and branched chain alkanes. The more toxic aromatic hydrocarbons are resistant; as a result, the toxicity of the oil has not been diminished. Where oil can be detected in the sediments there has been a kill of animals; in the most polluted areas the kill has been almost total. Shellfish that survived the accident have taken up the fuel oil. The 1970 crop of shellfish is as heavily polluted as was last year’s crop. Oysters transplanted to unpolluted water for as long as 6 months retained the oil without change in composition or concentration.
-
Technical ReportThe West Falmouth oil spill(Woods Hole Oceanographic Institution, 1972-04) Blumer, M. ; Sass, J.A spill of 650,000 to 700,000 1iters of #2 fuel oil in Buzzards Bay, Mass., USA, on September 16, 1969, has severely polluted the coastal waters, the marshes, the offshore sediments and the shell fish resources of Falmouth and of Bourne, Mass. In preliminary publications and reports we have discussed the chemical and biological data available during the first few months after the accident. The present report documents the continuation of our analytical effort; we include analyses of stations that had not previously been covered and present the data that were available by October, 1971. Three distinct, though partly overlapping, series of events followed the spill. First, within the first few hours or days after the accident, there was a very heavy kill of those organisms which came into contact with the oil. It extended over all phyla and over benthic and intertidal organisms. Next, within weeks or months after the spill, the oil pollution spread to areas that had not been immediately affected; and the kill extended, though in some cases more slowly than the spread of the oil, to outlying areas. Oil entered the marine food web and made the shellfish resources of our area unacceptable to human nutrition. The oil showed an unexpected persistence in the sediments and in marine life, especially in view of its relatively low boiling range and of earlier assertions that fuel oil pollution was transitory in nature and without long term consequences. For considerable time after the spill, the oil pollution of the sediments prevented the resettlement by the original fauna. Now, degradation of the oil has become evident. Biochemical and physical processes lead to a gradual reduction of the oil content of the polluted sediments. Concurrent with the degradation, there has been a gradual reduction in the immediate toxicity of the oil in the sediments. This has permitted resettlement of the polluted region first by the most resistant opportunists and later by a more varied and more normal fauna. However, oil-derived hydrocarbons have remained at all stations during the entire two year span for which data are now available, and it appears that the life span of pollution, even by a low boiling fuel oil must be measured in terms of many years. The eventual aim of this study is the documentation of the effects, the persistence and the eventual disappearance of pollutant hydrocarbons from a relatively small spill in a limited and previously clean coastal area. Of necessity, most of our analytical effort in the past was aimed at a survey of the extent of the oiling of the sediments and of some of the commercially important animals. As the degradation proceeds, we expect to devote a greater effort to a more detailed chemical analysis of the hydrocarbons remaining in the environment in order to define and understand the modes of degradation and to correlate chemical analyses with biological data. Parallel investigations on the weathering of different oils under other ecological and climatic circumstances are under way here and should, in combination with the West Falmouth study, give a more realistic assessment of the environmental hazard and persistence of crude oil than has been available until now.
-
Technical ReportLate Pleistocene-Holocene chemical stratigraphy and paleolimnology of the Rift Valley lakes of central Africa(Woods Hole Oceanographic Institution, 1973-05) Hecky, Robert E. ; Degens, Egon T.The interaction of climate and geology in Central Africa during Late Pleistocene and Holocene is examined. The study is based on sedimentological and limnological work on the main lakes of the Western Branch of the East African Rift Valley, particularly Lake Kivu, Changes in sediment chemistry, mineralogy and diatom assemblage provide a detailed histogram of lake level oscillations. Calculations indicate that the drop in lake level could be as high as 600 m for Tanganyika and 400 m for Kivu, Fluctuations in water levels.are the means for reconstruction of climatic events in tropical Africa of the last 15,000 years. Paleoclimatic comparison between tropical and temperate zones reveals that pluvial times coincide with the prominent interstadials in Europe, e.g. Bølling, Allerød, Climatic Optimum, and reversely, cool and dry periods in equatorial Africa with ice ages in the Northern Hemisphere. The African climatic sequence of pluvials and interpluvials is accompanied by corresponding periods of hydrothermal activity and quiescence. This may suggest that rain water exercises control on hydrothermal. activities.
-
ThesisAspects of the biogeochemistry of carbohydrates in aquatic environments(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1973-06) Mopper, KennethThe goal of this thesis is to examine the distribution and diagenesis of carbohydrates in aquatic environments. The following questions are studied: what is the carbohydrate composition of sediment in different environments (e.g., deep-sea oxic; shallow-sea oxic; deep-sea anoxic; fresh-water anoxic; brackish-water anoxic, etc.)? How does the environment at the sediment-water interface affect the composition of the carbohydrate input? How do sedimentary carbohydrates compare to plankton carbohydrates? How do metal-carbohydrate interactions and biological degradation affect the diagenesis of carbohydrates in recent sediments? Can fossil carbohydrates be used as a means to elucidate paleo-environments? In order to investigate these questions in a quantitative manner, a liquid chromatographic sugar analyzer sensitive to 10-10 moles was constructed. Various extraction techniques, involving acid hydrolysis and EDTA treatment, were thoroughly examined to determine lability of sugars, sources of contamination, maximum yields, and reproducibility. Furthermore, several experiments were performed to show that sugars extracted from sediment by EDTA were originally associated with in situ metal ion organic complexes. Although the carbohydrate compositions of sediment from different aquatic environments are remarkably similar, the degree of metal binding of carbohydrates varies between oxidizing and reducing sediments and appears to be related to the degree of biological degradation at the sedimentwater interface. In an oxic environment, biological degradation produces a highly metal-bound carbohydrate residue. In a reducing environment, the degree of biological activity is low (relative to oxic environments) and hence the degree of metal binding of the resulting carbohydrate residue is low. There is no evidence for further abiotic, alteration after burial in either environment. Sewage material dumped into a shallow oxic environment is degraded rapidly despite the high content of potentially toxic metals; these metals are probably tied-up in the metal bound carbohydrate residue. Metal binding appears to fix potentially soluble carbohydrates in situ, thereby inhibiting diffusion. This finding undercuts the previous belief that chromatographic separation of organic molecules along mineral surfaces is a significant diagenetic process. The relative abundances of sugars in acid extracts of sediment and plankton from different aquatic environments are similar; this similarity suggests that plankton is the main source of sedimentar carbohydrates. Carbohydrates in sediment may be used to interpret paleo-environmental fluctuations. For example, the degree of metal binding is indicative of the Eh at the sediment-water interface. The glucose and ribose contents of sediment may be used to estimate relative terrigenous and marine organic inputs, respectively. Paleo-eutrophication conditions in the surface waters also may be discerned.
-
ThesisThe interaction of metal ions at the hydrous manganese dioxide-solution interface(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1973-06) Murray, James W.An experimental study of the interaction of metal ions with the surface of hydrous manganese dioxide has been completed. The results of these experiments have greatly improved our qualitative understanding of the adsorption mechanism and have also provided a means of testing quantitatively the proposal that the concentration of cobalt in manganese rich marine samples is due to adsorption of cobalt from sea water by hydrous manganese dioxide. This study has shown that there are two reasons why manganese dioxide is an efficient scavenger of metal ions from sea water. These are coulombic attraction and specific adsorption. The coulombic attraction is in response to the surface charge that originates because of acid-base reactions at the surface. The surface charge is pH dependent, and the pH of zero point of charge for the hydrous manganese dioxide used in this study was 2.25. The surface charge increases rapidly for pH values greater than the pH of zero point of charge and reaches values of -100 μcoul/cm2 by pH 8.0. However, the high surface charge cannot explain all the adsorption. This is because some metal ions exhibìt a strong specific adsorption on the surface. This specific adsorption is a direct reaction of the metal ions with the surface, releasing one proton from the surface for each metal ion adsorbed. The energy of this specific interaction is frequently greater than the energy of electrostatic attraction. Adsorption on hydrous manganese dioxide and the magnitude of the specific adsorption both increased in the order: Na = K < Mn < Ca < Sr < Ba < Ni < Zn < Mn ≤ Co This suggests that the specific adsorption potential controls the adsorption selectivity of δMn02. An adsorption isotherm was constructed for cobalt, and these data were used to test the hypothesis that the enrichment of cobalt in the suspended matter of the Black Sea and in ferromanganoan sediments from the East Pacific Rise is due to adsorption of cobalt from sea water by manganese dioxide. The calculations indicate that adsorption is a feasible explanation for these examples.
-
ThesisThe characterization of humic substances in seawater(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-09) Stuermer, Daniel H.Humic substances were isolated in gram quantities from seawater by a newly developed procedure of adsorption on a crosslinked polystyrene-divinylbenzene resin. The chemical and physical characteristics of both humic acid and fulvic acid fractions were studied. The elemental composition, the acidimetric titration characteristics, the l3C: l2C ratios, and the ultraviolet-visible, fluorescence, and infrared spectra were determined. Molecular weight distributions of coastal and Sargasso Sea fulvic acids were measured by gel permeation chromatography. Structural features were further investigated by both proton and carbon-13 nuclear magnetic resonance spectroscopy. In addition, the fulvic acids and their derivatives were analyzed by low and high resolution mass spectrometry and combined gas chromatography-mass spectrometry (GC-MS). Amino acids and organic solvent soluble products in acid hydrolyzates were investigated. An array of biogenic hydrocarbons produced from fulvic acid by a new reduction scheme were characterized by GC-MS. The structural features of seawater humic substances are complex. They are highly aliphatic, polyfunctional materials containing both polar and nonpolar moieties. Hydrolyzable amino acids constitute a low percentage of the nitrogen. Fatty acids and other lipids are important structural components. Seawater humic substances have significant structural differences from those of terrestrial origin; this seems to result mainly from the relatively low input of lignin to the marine environment and the differences between the physical environment of the soil and the sea. A mechanism is proposed for the formation of seawater humic substances from amino acids, sugars and lipids. The effects and fate of humic substances in the sea are discussed.
-
Technical ReportBehavior of lobsters (Homarus americanus) in a semi-natural environment at ambient temperatures and under thermal stress(Woods Hole Oceanographic Institution, 1975-10) Stein, Lauren ; Jacobson, Stewart ; Atema, JelleIn January, 1974 we established semi-natural habitats in two 10ft. diameter, octagonal aquaria, with five lobsters (Homarus americanus) each, and several Cancer irroratus, Anguilla rostrata, Pseudopleuronectes americanus and Tautoglabrus adspersus. The lobsters, with respect to size and sex, were identical as possible between tanks, as were the numbers of other species. The aquaria, which received ambient seawater, were arranged identically with an oyster shell substrate, and cement blocks, rocks and ceramic pipes to provide a surplus of shelters. Observations, spanning from February through August, were made both during the day, following feeding, and (using red light) just after sunset, when lobsters are active under natural conditions. Types of behavior we were able to quantify included occupation of specific shelters, feeding, activity and social behavior. In our large aquaria the lobsters appeared to be much less aggressive than generally has been reported. Aggression was most frequent during feeding. Observations at night revealed few encounters, and these were usually either one sided avoidance without pursuit, or mutual ritualized displays. Neither an animal's size nor sex seemed to determine its relative dominance. Dominance shifted somewhat between different animals during the study, and complicating this picture was possible territorial behavior in the larger individuals. In one tank, only the two adult females were territorial from February through mid May, following which no lobster showed stability of residence. In the second tank, only one animal, a female, was territorial for more than several weeks, until early June, when the largest male established a reproductive territory lasting until the end of August. Even in our large aquaria space may have been too limited for all animals to be territorial. Lobsters appeared to lose their position in the hierarchy just prior for up to a month or more following the molt. Such animals were often observed on top of shelters, in exposed locations, where other lobsters apparently did not harass them. Although captive lobsters are considered quite cannibalistic, we lost only one animal, a juvenile female, out of six molts. In our large aquaria, female lobsters about to molt sought out, took up residence, and actively courted the tank's largest male. The males were very non-aggressive toward these females, and yet during this period made violent attacks against other males as well as fish. In each case following mating, the males retired to the shelter and fed on the cast shell. Cohabitation, in or around the males' residences, continued for several days following mating. Diurnal activity, which was evoked by the presence of food, showed little change over the range of 5-28°C. Nocturnal activity, vihich was more spontaneous, was similar in both tanks through mid June (temp. range 5-18°C). The level of activity was as high in late February - early March as in late May, with a dip in activity in late March - late April, a period marked by storms. From mid June on, the nocturnal activity in tank I increased with the increasing temperature, leveling off approximately vihen the peak temperature of 28°C was reached. In contrast, activity in tank II did not increase at temperatures above 20°C, and remained at a much lower level than in tank I. Although patterns of residence and dominance in the lobsters changed seasonally, the direction of change was rather different in each tank and did not seem correlated with temperature. Other factors, such as molting and loss of dominance prior to mating in previously aggressive females, were probably more important than temperature effects. The frequency of temperature range 22-28°C was similar to levels at ambient temperatures. Interspecific relations between lobsters and the other species were mainly pacific, although predation on Cancer by Hi. americanus may have occurred. The response of the eels (Anguilla rostrata) to temperature increases was consistent between tanks. Swimming was first observed at 8°C, and feeding at 10°C. Further, the eels in both tanks became markedly aggressive when the temperature reached 26°C.
-
Technical ReportApplications of PB-210/RA-226 and PO-210/PB-210 disequilibria in the study of marine geochemical processes(Woods Hole Oceanographic Institution, 1976-02) Bacon, Michael P.The distribution of Pb-210 and Po-210 in dissolved (0.4 micron) phases has been measured at ten stations in the tropical and eastern North Atlantic and at two stations in the Pacific. Both radionuclides occur principally in the dissolved phase. Unsupported Pb-210 activities, maintained by flux from the atmosphere, are present in the surface mixed layer and penetrate into the thermocline to depths of about 500 m. Dissolved Po-210 is ordinarily present in the mixed layer at less than equilibrium concentrations, suggesting rapid biological removal of this nuclide. Particulate matter is enriched in Po-210, with Po-210/Pb-210 activity ratios greater than 1.0, similar to those reported for phytoplankton. Box-model calculations yield a 2-y residence time for Pb-210 and a 0.6-y residence time for Po-210 in the mixed layer. These residence times are considerably longer than the time calculated for turnover of particles in the mixed layer (about 0.1 y). At depths of 100-300 m, Po-210 maxima occur and unsupported Po-210 is frequently present. Calculations indicate that at least 50% of the Po-210 removed from the mixed layer is recycled within the thermocline. Similar calculations for Pb-210 suggest much lower recycling efficiencies. Comparison of the Pb-210 distribution with the reported distribution of Ra-226 at nearby GEOSECS. stations has confirmed the widespread existence of a Pb-210/Ra-226 disequilibrium in the deep sea. Vertical profiles of particulate Pb-210 were used to test the hypothesis that Pb-210 is removed from deepwater by in situ scavenging. With the exception of one profile taken near the Mid-Atlantic Ridge, significant vertical gradients in particulate Pb-210 concentration were not observed, and it is necessary to invoke exceptionally high particle sinking velocities (>10 m/d) to account for the inferred Pb-210 flux. It is proposed that an additional sink for Pb-210 in the deep sea must be sought. Estimates of the dissolved Pb-210/Ra-226 activity ratio at depths greater than 1,000 m range from 0.2 to 0.8 and reveal a systematic increase, in both vertical and horizontal directions, with increasing distance from the sea floor. This observation implies rapid scavenging of Pb-210 at the sediment-water interface and is consistent with a horizontal eddy diffusivity of 3-6 x 107 cm2/s. The more reactive element Po, on the other hand, shows evidence of rapid in situ scavenging. In filtered sea water, Po-210 is deficient, on the average, by ca. 10% relative to Pb-210; a corresponding enrichment is found in the particulate phase. Total inventories of Pb-210 and Po-210 over the entire water column, however, show no significant departure from secular equilibrium, and reliable estimates of particle sinking rates cannot be made.
-
ThesisDissolved inorganic and particulate iodine in the oceans(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1976-02) Wong, George T. F.Analytical methods have been developed for the determination of iodate, iodide and particulate iodine in sea water. Iodate is converted to tri-iodide and the absorbance of tri-iodide at 353 nm is measured. The precision of this method is ca. ±3%. Iodide is first separated from most other anions by an AG 1-x8 anion exchange column and then precipitated as palladous iodide with elemental palladium as the carrier. The precipitate is analyzed by neutron activation analysis. The precision of the method is ±5% and the reagent blank is 0.005 uM. Marine suspended matter is collected by passing sea water under pressure through a 0.6 u (37 mm diameter) Nuclepore filter. The iodine content of the particles is determined by neutron activation analysis. The method has excellent reproducibility and the filter blank is ca. 3 ng. Iodate is depleted in the surface waters of the Equatorial Atlantic. The depletion is more pronounced than in the Argentine Basin and possibly reflects the higher productivity in the equatorial area. Superimposed on this feature, a thin lens of water, of a few tens of meters thick and with high iodate concentrations, can be traced across the Atlantic. Along the equator, this lens occurs at 80 m at 33˚W and rises upwards to 55 m at 10˚W and it coincides with a core of highly saline water which is characteristic of the Equatorial Undercurrent. Longitudinal sections reflect the complexity of the equatorial current system. At least three cores of water with high iodate concentrations may be identified. These waters may be transported to the equatorial region from the highly productive areas along the north-western and western African coasts and the Amazon plume. In anoxic basins, the concentration of iodide increases rapidly in the mixing zone from 0.02 uM to 0.44 uM in the Cariaco Trench and from 0.01 uM to 0.23 uM in the Black Sea. The iodate concentration, meanwhile. decreases to zero. A maximum in the total iodine to salinity ratio is observed just above the oxygen-sulfide interface (15 to 17 nmoles/g); it is suggestive of particle dissolution in a strong pycnocline. Below the interface, the total iodine to salinity ratio is constant at 12.3 nmoles/g in the anoxic zone of the Cariaco Trench, whereas, in the Black Sea, it increases with depth from 10.0 to 19.4 nmoles/g and suggests a possible flux of iodide from the sediments. By considering the distribution of iodate and iodide in oxic and anoxic basins and our present analytical capability, the lower limit of the pE of the oceans is estimated to be 10.7. Thermodynamic considerations further suggest that the iodide-iodate couple is a poor indica tor for the pE of the oceans with a limited usable range of 10.0 to 10.7. In the Gulf of Maine during the winter of 1974 to 1975. the effect of winter mixing was conspicuous. Uniform concentrations of iodide and iodate were observed in the mixed layer above the sill. The absence of a depletion of iodate and the low iodide concentration (0.04 uM) in the surface waters reflect the low biological activity in this region during winters. Profiles of particulate iodine are characterized by high concentrations in the euphotic zone (>5 ng/kg), and lower concentrations (< 2 ng/kg) at greater depths. Occasionally, high concentrations have also been observed in the nepheloid layer. The iodine-containing particles are probably biogenic. A section in the Western Atlantic from 75°N to 55˚S shows evidence of the transport of particles along isopycnals and the re-suspension of surface sediments to considerable distance from the bottom. The standing crops in the top 200 m may be qualitatively correlated with the primary productivity. Thermodynamic considerations show that iodide is a metastable form at the pH of sea water. Laboratory studies fail to show the oxidation of iodide at measurable rates. Elemental iodine is unstable in sea water and undergoes hydrolysis to form hypoiodous acid in seconds. Hypoiodous acid is also unstable and has a life time of minutes to hours. It may react with organic compounds to form iodinated derivatives or it may be reduced to iodide by a reducing agent. The disproportionation of hypoiodite to form iodate seems to be a slower process. A possible chemical cycle for iodine in the marine environment is proposed.
-
ThesisThe marine geochemistry of trace metals(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1976-04) Boyle, Edward A.The marine geochemical cycles of iron, copper, nickel, and cadmium were studied in order to provide a basis for oceanographic models for trace metals. Copper, nickel, and cadmium can be determined in a 100 ml seawater sample using cobalt pyrrolidine dithioacarbamate chelate coprecipitation and graphite atomizer atomic absorption spectrometry. Concentration ranges likely to be encountered and estimated (1δ) analytical precisions are copper, 1 to 6 nanomole/kg (±0.1); nickel, 3 to 12 nanomole/kg (±0.3); and cadmium, 0. 0 to 1.1 nanomole/kg (±0.1). The technique may be applied to freshwater samples with slight modification. A survey of several east coast U. S. estuaries established that an iron removal process occurs commonly when rivers mix with seawater. Laboratory mixing experiments using water from the Merrimack River (Mass.) and the Mullica River (New Jersey) demonstrated that rapid iron precipitation occurs as negatively-charged iron-organic colloids react with seawater cations and coagulate. This phenomenom was modeled using a synthetic, organic-stabilized colloidal suspension of goethite. The generality of the mechanism suggests that the world-average net river input of iron to the oceans is less than 1 μmole/kg of river water, an order of magnitude below previous estimates. Profiles of cadmium were obtained for 3 GEOSECS stations in the Pacific Ocean. Cadmium shows a consistent linear correlation with phosphate which demonstrates that cadmium is regenerated in a shallow cycle within the water column. The water column correlation is consistent with data on cadmium in marine organisms. Cadmium is enriched in upwelling regions which explains reports of cadmium enrichment in plankton from the Baja California upwelling region. Copper and nickel measurements have been made for three profiles from the Pacific Ocean. Observed copper concentrations range from 1 to 6 nanomole/kg; nickel varies from 3 to 12 nanomole/kg. Copper and nickel are removed from surface waters by uptake into organisms. As noted previously, nickel is regenerated partially in a shallow cycle (like P) and also in a deep cycle (like Ba). Copper is regenerated from biological debris at the bottom but is also scavenged from the mid and deep water column by an undetermined mechanism. The scavenging residence time is 1400 years. An estimate for the continental input of Ni, 7 nanomole/kg of river water, and Cu, 18 nanomole/kg of river water, was derived from measurements in the Amazon estuary. The oceanic residence times for nickel and copper are about 10,000 years. Evidence available on the uptake laws for trace metals by plankton suggests that a consistent relationship between the uptake law and the depth of regeneration may apply.
-
ThesisThe chemistry, biology, and vertical flux of oceanic particulate matter(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1977-01) Bishop, James K. B.Particulate matter samples, split into 53 μm size fractions have been obtained using a Large Volume in situ Filtration System (LVFS) during the SOUTHLANT expedition, R/V CHAIN 115. Profiles to 400 m are reported for LVFS Stns. 2 and 4-8. Stns. 4, 5, and 8 (S. E. Atlantic, coastal waters near Walvis Bay and Cape Town, high biological productivity); Stns. 6 and 2 (S.E. Atlantic, Walvis Bay region and equatorial Atlantic, moderate productivity); and Sta. 7 (S.E. Atlantic, edge of central gyre, low productivity) formed a suite of samples for the study of the chemical, biological, morpholigical distributions and of the vertical mass flux of particulate matter as a function of biological productivity. All samples were analysed for Na, K, Mg, Ca, carbonate, opal, Sr, C and N and those from Sta. 2 were further analysed for P, Fe, δ13C, 7Be, 214Bi, 214Pb, (226Ra), 210Po, and 210Pb. Biological distributions of Acantharia, dinoflagellates, coccolithophorids, Foraminifera, diatoms, silicoflagellates, Radiolaria, and tintinnids were made by light microscopy (LM) and augmented by scanning electron microscopy (SEM). Size and morphological distributions of the >53 μm particles, especially Foraminifera, Acantharia, fecal pellets, and fecal matter have been determined by LM and SEM. The particle distributions were controlled at all stations by processes of production, consumption, fragmentation, and aggregation. Maxima in organism abundance and particulate mass were generally coincident. They were found nearest the surface when the mixed layer was absent or poorly developed, and at the base of the mixed layer at the other stations. Organism vertical distributions showed consistent features: Acantharia, and dinoflagellates were always nearest the surface; Foraminifera and diatoms were shallower than or at the base of the mixed layer; Radiolaria and tintinnids were found in the upper thermocline. Coccolithophorids and diatoms were the dominant sources of particulate carbonate and opal in the near surface waters, coccoliths and diatom fragments, deeper. Features of the distributions of particulate matter attributed to the feeding activities of zooplankton were: strong concentration gradients in organisms, mass, and organic matter; enrichment of the >53 μm fraction with coccoliths causing the steady decrease in >53 μm Si/carbonate ratio with depth from values as high as 45 to values near 1.0 at 400 m; the decrease in organic content with depth from values near 100 % near the surface to 50 and 60% at 400 m for the <53 and >53 μm size fractions; the fragmentation of most material below 100 m; and the production of fecal pellets and fecal matter which are carriers of fine material to the sea floor. Other features were: the nearly constant organic C/N ratios (7.3±0.5 δ) found for the 1-53 μm fractions at Stns. 4, 5, 6, and 8 compared with the steady increase observed at Stns. 2 and 7 with depth; particulate carbon was rather uniformy distributed below 200 m with concentrations showing a mild reflection of surface productivity; the <1 μC/N and δ13C values are lower and lighter than the 1-53 μm fraction, perhaps indicative of the presence of marine bacteria; the Ca/carbonate ratios in most samples significantly exceeded 1.0, values as high as 2.5 were observed at Sta. 8; the xs Ca and K have shallow regenerative cycles and contrast with Mg which is bound to a refractory component of organic matter; based on a organic C/ xs Ca ratio of 100-200:1 for surfàce samples, the cycling of xs Ca was calculated to be 1-2 x 1013mol/cm2/y compared with the production of carbonate, 7±2 x 1013 mol/cm2/y. Chemical effects noted were: organic matter had both binding capabilities and ion-exchange capacity for major and minor ions present in seawater. Acantharia (SrS04) dissolve most significantly below 200 m at Sta.2. The vertical mass fluxes through 400 m at Stas. 2, 5, 6, and 7 were calculated from size distributions measured in 1 m3 in seawater for Foramifera, fecal pellets, and fecal matter. Two flux models were used together with Junge distributions for these calculations. Fecal matter and Forainifera transported most mass at Stns. 2 and 5 where the fluxes were between 2 and 3, and 5 and 6 gm/cm2/1000y respectively; fècal matter, Foramnifera, and fecal pellets contributed equally to the .9-1.3gm/cm2/1000y flux at Sta. 6; and fecal pellets and Foraminifera were the carriers of 0.1-0.3 gm/cm2/1000y to the sea floor. Corresponding chemical fluxes of organic carbon, carbonate, and opal were: 80-90, 11-24, and ~10 mmol/cm2/1000y at Sta. 5; 15-20, 2.7-5.0 and 1.7-2.5 mmol/cm2/1000y at Sta. 6; 1-4, 0.6-1.5, and 0.1-0.3 mmol/cm2/1000y at Sta. 7, and 40-65, 4.6-7.4, and 4.9-7.9 mmol/cm2/1000y at station 2. Over 90% of the organic matter produced in the euphotic zone is recycled in the upper 400 m. The efficiency is nearly 99% in areas of low productivity; the organic to carbonate carbon ratios are highest at locations where the flux is greatest as are the Si/carbonate ratios. Besides carbonate, opal, celestite, and other mineral phases, organic matter may be a significant carrier of minor and trace elements to the deep ocean.
-
ThesisThe marine geochemistry of methane(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1977-08) Scranton, Mary I.In the highly productive coastal surface waters near Walvis Bay, methane is present in concentrations considerably above those which would be predicted from solubility equilibrium with the atmosphere. A one dimensional diffusive model and a one dimensional horizontal advection diffusion model were used to describe the methane distribution. Evaluation of the model fits to the data suggests that both advective supply of methane-rich coastal waters and in situ biological methane production are important sources for the mixed layer methane excess. The complexity of the hydrographic regime near Walvis Bay makes it impossible to make a quantitative estimate of the rate of methane production. In the less productive Murray-Wilkinson Basin in the Gulf of Maine, a mixed layer methane excess is also observed. Methane concentrations are closely correlated with hydrographic parameters and the source of methane at a middepth maximum appears to be the highly anoxic sediments in the adjoining Franklin Basin. Diffusion of methane from the middepth maximum is probably adequate to maintain the surface methane excess against loss across the air-sea interface. Coastal waters are frequently enriched in methane, and it has been shown that advective supply of these methane-rich waters may be a significant source of methane for the mixed layer near the coast. Thus the widespread occurrence of a methane maximum at the base of the mixed layer in the open ocean, coupled with surface waters typically 30-70% supersaturated with respect to solubility equilbrium, suggests that advective supply of methane might be an important methane source for the open ocean as well. However, a study of the western subtropical Atlantic shows that advective transport can probably supply only a fraction of the methane present in the maximum. Also the loss of methane across the air-sea interface was observed to be twenty times greater than the flux from the maximum. Thus in situ methane production must be very important to the open ocean methane distribution. A series of phytoplankton culture experiments demonstrated that cultures of both Coccolithus huxleyi and Thalassiosira pseudonana produce trace amounts of methane during logarithmic growth. (Because the cultures are highly oxygenated, anaerobic methane bacteria can be neglected as methane sources. However heterotrophic bacteria cannot be excluded as possible sources of methane to the cultures.) After three algal generations, the rate of methane increase closely parallels the growth curve suggesting that the methane is in fact coming from the algae. A methane production rate of 2 x 10-10 nmole methane/viable cell/hr was calculated from the data. This rate is three to four orders of magnitude slower than the rates of oxygen consumption and glutamate and glucose uptake measured by other workers. for algae and bacteria. The methane production rate calculated from the culture experiments is the correct order of magnitude to account for the methane production occurring in the open ocean. Methane is present in quite low concentrations in the deep ocean. By calculating water mass ages from GEOSECS and other data, it is possible to estimate methane consumption rates in the deep sea. Methane consumption is rapid at first (probably greater than 0.06 nmole/l/yr). At depth consumption appears extremely slow. This may be due to the fact that the methane concentrations in the deep sea are so low that methane oxidizing bacteria cannot use methane as a substrate, or due to reduced metabolic activity in the bacteria at the high pressures and low temperatures of the sea floor. Methane is present in very high concentrations in anoxic basins, indicating that methanogenic bacteria are active. However, near the anoxic-oxic interface in both the Black Sea and the Cariaco Trench a one dimensional advection diffusion model predicts that methane consumption is occurring in the anoxic zone. In the Black Sea the methane depletion may be indicative of the presence of rapid methane oxidation near the Bosporus overflow. However in the Cariaco Trench the validity of such an explanation is difficult to evaluate since the overflow process is so poorly understood. A box model for the Trench has been developed which incorporates time dependence and supply of chemical species to the water from the sediments at all depths in the Trench. This model can explain the silica and sulfide data quite well, but methane depletion near the interface, relative to the model predictions, still occurs. Thus either anaerobic methane oxidation or decreased methane production in the sediments must be hypothesized.
-
Technical ReportReport A, chemical oceanographic data from the Persian Gulf and Gulf of Oman(Woods Hole Oceanographic Institution, 1978-05) Brewer, Peter G. ; Fleer, Alan P. ; Kadar, Susan ; Smith, Clarence L.During February and March of 1977 a major geochemical, biological and geophysical survey of the Persian Gulf and adjacent waters was carried out on R/V ATLANTIS II, Cruise 93, Legs 17 and 18. It is the purpose of this report to present the chemical oceanographic data obtained, together with a documentation of the analytical techniques and a simple discussion of the major features observed. Of the 54 hydrographic stations (ATLANTIS II, Stations 2357-2410) occupied during Leg 17, 45 may be said to be in the Persian Gulf proper, the remainder being in the Gulf of Oman and the northwestern Arabian Sea.
-
Technical ReportMethane production in the waters off Walvis Bay(Woods Hole Oceanographic Institution, 1978-09) Scranton, Mary I. ; Farrington, John W.Nine stations were occupied in the vicinity of Walvis Bay, Namibia, during a detailed study of the distribution of methane in this highly productive coastal environment. The principal features of the observed coastal methane distribution included ( I) excess methane in the mixed layer of from 2 times to greater than 300 times solubility equilibrium with the atmosphere, (2) a subsurface maximum, located in the top of the pycnocline, at which concentrations ranged from 2.6 to 440 times solubility equilibrium. (3) an intermediate depth minimum, where concentrations were comparable to those offshore at similar depths and which we attribute to the influence of onshore movement of subsurface offshore water, and (4) a bottom maximum, which we attribute to input of methane to the water column from the anoxic sediments in the Walvis Bay area. An attempt was made to identify the relative importance for methane supply to the coastal mixed layer of in situ biological production and of eddy diffusive and advective transport of methane-rich water which has been in contact with the bottom at the coast. Calculations suggest that both in situ production and physical processes are major sources of excess methane for the highly productive coastal surface waters. However, the complicated circulation patterns make quantification extremely difficult.
-
ThesisVolatile organic compounds in seawater(Woods Hole Oceanographic Institution, 1979-01) Gschwend, Philip M.Vapor phase stripping and solid adsorbent trapping were applied to seawater and related samples to concentrate volatile organic compounds. The concentrates were subsequently analyzed by glass capillary gas chromatography and combined gas chromatography-mass spectrometry. The compound identities and the spatial and temporal distributions of their concentrations were used to determine some sources, transformations, and transport mechanisms of organic matter in the sea. Volatile organic compounds were determined in seawater samples from the Sargasso Sea, the western Equatorial Atlantic, and the upwelling region off Peru. Pentadecane was present in all three areas in surface samples at 10-40ng/kg and decreased to 1-2 ng/kg in the deep water. A source related to the transformation of the algal fatty acid, hexadecaugic acid, by zooplankton is proposed since anthropogenic and direct phytoplankton sources are unlikely. C2-alkylated benzenes were found in the upwelled water off Peru at about 4 ng/kg in the surface (5 and 20m), 3 ng/kg below the thermocline (100m), and 2 ng/kg or less in deeper water. A surface or atmospheric source is required to produce this distribution. C6-C10 aldehydes were also found in seawater from off Peru. The direct correlation of their concentrations with chlorophyll a and with oxygen indicated that they are derived from chemical oxidation of algal metabolites, for example, unsaturated fatty acids. Total volatiles in the oligotrophic Sargasso Sea were about 10-30 ng/kg while the biologically productive upwelling region off Peru contained up to 100 ng/kg. The temporal variations of volatile organic compound concentrations were investigated in coastal seawater from Vineyard Sound, Massachusetts. Pentadecane and heptadecane showed large summertime concentration increases which were ascribed to benthic algal sources. Laboratory incubations of benthic algal samples supported this conclusion. The saturated hydrocarbons, from C13-C17, and alkylated benzenes and naphthalenes were all abundant after an oil spill several miles from the sampling site. C2- and C3- benzenes were the most persistently abundant volatile compounds and their concentrations were observed to be 2-10 times higher than average immediately after summer weekends, peak periods of tourist and recreational activities on Cape Cod. Naphthalene and its homologues were more abundant in the winter than in the summer. C6-C10 aldehydes were observed year-round, but showed a concentration maximum at the time of the late-winter phytoplankton bloom. C12-C15 aldehydes were also found in abundance at that time. Oxidation of algal matter by zooplankton or photochemically-produced oxidizing agents may produce the aldehydes, since laboratory cultures of phytoplankton did not produce these oxygenated volatiles. An alkene, structurally similar to the known benthic algal gamone, fucoserraten, was also found in Vineyard Sound seawater and in the upwelling region off Peru. Its appearance in Vineyard Sound samples coincided with the period of expected algal reproductive activity in February and March. Dimethyl polysulfides were found in coastal seawater. They may be produced within the water from precursors such as methyl mercaptan or other known polysulfide metabolites. Total volatile concentrations in Vineyard Sound seawater varied between 2OO and 500 ng/kg for the period from January to June. Maximum concentrations occurred during the late-winter phytoplankton bloom and again in the spring from anthropogenic inputs of hydrocarbons. The highest concentrations of C2- and C3-benzenes found in Vineyard Sound seawater coincided with motorboat use in the immediate vicinity of the sampling station. The average year-round isomer distribution most closely resembled distributions from gasoline and auto exhaust dissolved in seawater, consistent with an inboard or inboard/outboard motorboat source. Atmospheric and runoff delivery of C2- and C3-benzenes to Vineyard Sound seawater during the period from spring through fall was concluded to be of lesser importance. The atmosphere may serve as a buffer for seawater concentrations of the aromatic compounds, supporting low concentrations in the winter and limiting high concentrations in the summer.
-
Technical ReportWoods Hole Oceanographic Institution Helium Isotope Laboratory data release no. 1(Woods Hole Oceanographic Institution, 1979-07) Jenkins, William J. ; Collentro, William V. ; Boudreau, Richard D.This report summarizes technique, estimated precisions and results for 3H and 3He analyses made on three cruises in the Sargasso Sea. In addition, a statistical treatment is made on 36 surface (≤10m) 3He/4He analyses to obtain an estimate of the solubility isotope effect and its temperature dependence to be ( α - 1) X 1000 °/oo = -(17.3 ~ 0.8) +(0.28 ~ 0.06) T (°C) with a regression scatter of 2.6 °/oo and a linear correlation coefficient of 0.640.
-
Technical ReportHydrographic and nutrient data from R/V Knorr cruise 73, leg 2 : February to March, 1978 : off the coast of Peru(Woods Hole Oceanographic Institution, 1980-01) Gagosian, Robert B. ; Loder, Theodore ; Nigrelli, Gale ; Mlodzinska, Zofia ; Love, James ; Kogelschatz, JaneIn February and March of 1978 a major cruise was undertaken on the R/V KNORR off the Peruvian coast near 15°S in order to investigate the organic biogeochemical processes associated with upwelling areas. The purpose of this report is to collate the large amount of hydrographic, nutrient, and plankton data generated from various investigators on this cruise and use the report as a standard for the cruise participants. Data for temperature, salinity, oxygen, nitrate, nitrite, ammonium, phosphate, silicate, chlorophyll a, productivity indices, and carbon fixation rates are given.
-
Technical ReportGas chromatography-mass spectrometry facility : recent improvements and applications(Woods Hole Oceanographic Institution, 1980-03) Frew, Nelson M. ; Sawdo, Richard M.Marine organic and organic geochemical studies require the best available performance in trace analysis of organic compounds in environmental samples. This report briefly outlines some of the recent improvements in the experimental capabilities of the Chemistry Department Gas Chromatography/Mass Spectrometry Facility (GC/MS Facility) from a user-oriented and non-technical viewpoint. These improvements include principally the interfacing of high performance glass capillary columns with Finnigan 1015 and 3200 quadrupole mass spectrometers, and the adaptation of the latter for use with selective chemical ionization (CI) techniques. Some of the new capabilities available using combined glass capillary GC/EI-MS and CI-MS are illustrated with examples from research in several areas of marine organic chemistry. These include studies of volatile organics in seawater, the distributions of various lipid class compounds in marine phytoplankton, sediments and particulate matter, and the behavior of anthropogenic pollutants in natural and artificial marine ecosystems.