Ocean Fertilization Research Articles

Plenary lecture: The use of iron and other trace element fertilizers in mitigating global warming

Abstract If current trends continue, before the end of the next century atmospheric CO2 levels will be about double those of a century ago. Other greenhouse gases, including methane and chlorofluorocarbons, also are increasing at similar or even higher rates. The effects of such global atmospheric changes on climate, and, thus, on agriculture, forestry and natural ecosystems, are uncertain. Only the results of the planetary “experiment”; itself will provide a definitive answer. Current projections range from catastrophic to favorable. Prudence suggests that steps be taken to slow down these rapid atmospheric changes, even in the absence of a definitive estimate of risks. Natural sinks for CO2 already account for the disappearance of as much as 60% of anthropogenic CO2 production due to fossil fuel combustion, deforestation, and soil organic carbon oxidation. Thus, current rates of increases in atmospheric CO2, about 0.4% per year, could be cut in half by reducing anthropogenic CO2 outputs by 20%, or increasing sinks by a similar amount. Such a reduction would significantly reduce the risks of major climatic changes. Programs to reduce greenhouse gas emissions are being instituted in Japan and Europe, but not in the U.S. or most other countries. Reduction of CO2 buildup must focus on the reduction of the major sources ‐fossil fuel usage, deforestation, soil carbon oxidation ‐ and on increasing sinks. The only practical methods for increasing CO2 sinks are based on photosynthesis, primarily through increased C storage in standing tree biomass, the use biomass as substitutes for fossil fuels, and, possibly, through the stimulation of ocean primary productivity by iron fertilization. Fertilizing forests and oceans with iron and other trace elements to increase primary productivity and CO2 sequestration is an attractive concept Application of small quantities of trace elements, could, in principle, result in the sequestration of many tons of CO2. Iron limits primary productivity in some ocean areas. How to practically fertilize the oceans with iron, the environmental impacts of such additions, and their effectiveness in reducing atmospheric CO2 concentrations are controversial issues. Long‐term studies of ocean fertilization will be required, and such schemes can not be included in current global warming mitigation options. Iron and other trace elements are often limiting factors in agriculture, and many reports exist of such limitations in managed forestry. However, it is presently unclear how widespread such deficiencies are in managed forests, and global effects on CO2 balances can not be projected. Fertilization with major nutrients ‐ P, K, and N ‐ is often effective in stimulating forest productivity and could be an economical approach to large‐scale CO2 sequestration. Increased forest fertilization with major nutrients will, in many cases, also require applications of some trace elements. In conclusion, forest fertilization with trace elements and even major nutrients could be an affordable and near‐term method of reducing future global warming.

Uvigerina proboscidea abundances and paleoceanography of the northern Indian Ocean DSDP Site 214 during the Late Neogene

This study attempts to understand the significance of Uvigerina proboscidea in paleoceanographic reconstructions at the northern (tropical) Indian Ocean DSDP Site 214 from the Late Miocene through the Pleistocene. In this interval at this site, U. proboscidea is the most abundant species of the benthic assemblage and shows abrupt frequency changes (about 1–74%). Based on relative percentages of U. proboscidea calibrated with oxygen and carbon isotope record and the sediment accumulation rates, the modern distribution of the species in the Indian Ocean, and other evidence, the peaks of abundance of U. proboscidea are inferred to represent times of high-surface productivity. This productivity is related to intensified trade winds during strong southwest (SW) Indian monsoons, causing widespread upwelling along equatorial divergence in the Indian Ocean. The sudden increase of U. proboscidea abundance at approximately 8.5–7.5 Ma reflects significant upwelling at the equatorial divergence. This event corresponds to the permanent build-up of West Antarctic ice sheets, and a major increase in SW Indian monsoons related upwelling in the northwestern Indian Ocean. The Chron-6 carbon shift at approximately 6.2 Ma is marked by another peak of abundance, reflecting widespread ocean fertility. The highest abundances of U. proboscidea and highest sediment accumulation rates occur between 5.8 and 5.1 Ma, which coincides with the greatest development of Antarctic ice sheets and strong southwest monsoons. The higher percentages at 3.2–3.1 Ma, approximately 2.4 Ma, and 1.6 Ma all represent phases of high productivity at the equatorial divergence.

Barium in Deep‐Sea Sediment: A Geochemical Proxy for Paleoproductivity

We used sediment traps to define the particulate fluxes of barium and organic carbon and investigate the use of barium as a proxy for ocean fertility. Strong correlations between Corg and Ba fluxes indicate a link between upper ocean biological processes and barium flux to the seafloor. The ratio of organic carbon to barium decreases systematically with water depth. Data from 10 sites indicate that organic debris settling from the 200‐m depth has a Corg /Ba ratio of approximately 200. The systematic decrease in this ratio with increasing water depth results from the simultaneous decay of organic matter and uptake of Ba in settling particles. This behavior provides additional evidence that the formation of barite in oceanic particles is a consequence of decomposition/uptake in microenvironments rather than the secretion of barite by specific organisms. The decrease of the Corg/Ba ratio with depth is greatest in the North Pacific followed by the equatorial Pacific and is lowest in the western Atlantic. Since this spatial pattern is consistent with the variations in the deep‐ocean barium contents which increase along the path of bottom water flow from the Atlantic to the North Pacific, it suggests that the particulate barium uptake and flux is enhanced by higher barium contents in the intermediate and deep waters of the ocean. Consequently, we have combined our particle flux data with existing water column Ba data to define an algorithm relating new productivity, dissolved barium contents, water depth, and particulate barium flux. This relationship provides a basis of applying barium flux measurements in sediments to estimating new production. In order to use barium as an indicator of productivity, it will be necessary to evaluate inputs from hydrothermal and aluminosilicate sources and xenophyophors. The application of a sequential leach procedure to the trap material indicates that 50‐70% of the Ba in settling particles is in the form of barite and the remaining is adsorbed or bound to carbonates. Normative analysis demonstrates that in nearshore areas the contribution of barium from aluminosilicate sources can dominate that from biogenic inputs. It appears that normative estimates of biogenic barium contents can be made with accuracy if less than 50% of the Ba is associated with aluminosilicates; i.e., is of terrigenous origin. Since diagenetic mobilization of Ba can occur in reduced and suboxic sediments, highly productive nearshore areas also are likely to be inappropriate sites to use Ba measurements as productivity indicators. Comparisons between the rain rates of particulate Ba to the seafloor and the burial rate indicate that approximately 30% of the Ba rain is preserved. Although the preservation factor does not appear to be constant, it may be possible to predict the extent of preservation from an empirical relationship with the mass accumulation rate. These observations indicate that measurement of Ba burial fluxes in sediments can provide quantitative information on the paleoproductivity of the oceans. Joining the relationship between barium rain and burial with the barium and organic carbon algorithm, we make estimates of the new production in the northern California Current during the last 18,000 years. This calculation suggests that new production was at least a factor of 2 lower at this site during the last glacial maximum.

Water depth and diagenetic constraints on the use of barium as a palaeoproductivity indicator

Abstract Sediments underneath the high productivity areas of the coastal upwelling and equatorial divergence zones in the Pacific and Indian oceans are enriched in barium, and on this basis the barium content of the sediments has long been suggested as a potential palaeoproductivity indicator. Analyses of sediments from the Peru margin corroborate the pattern of enhanced barium accumulation in areas of high primary productivity in the deep ocean, but also show that this pattern cannot be extended to shallow-water deposits. Sediments from the Peru shelf lack any barium enrichment, whereas this element is significantly enriched in slope and basinal deposits in water columns deeper than 2000 m. This depth effect is further illustrated at Site 682 located in the rapidly subsiding Lima Basin. The Quaternary sequence deposited at water depths >3000 m is enriched in organic carbon, opal and biogenic barium. The Miocene sediments, although deposited under highly productive waters associated with a coastal upwelling centre, do not show an enrichment in the barium record corresponding to the very high organic carbon and opal levels; a pattern that is consistent with deposition in shallow basins. In addition to the effect of water depth on the barium distribution, overprinting of primary signals can be observed in sediments from upwelling areas undergoing strong anoxic diagenesis. Microcrystalline barite is partly dissolved in intervals depleted in interstitial sulphate as shown for sediments from the Peru margin. Dissolution of barite in sulphate depleted intervals of deep water sections leads to high barium concentrations near the termination of the sulphate reducing zone, where downward sulphate and upward barium diffusion foster local barite precipitation in diagenetic fronts. The barium distribution in sedimentary oxic and suboxic environments at deep water depositional sites has a high potential as a palaeoproductivity indicator; however, barium accumulation as a proxy for ocean fertility should be used with caution in areas of varying water depths and in anoxic diagenetic environments where sulphate depletion undersaturates the interstitial waters with respect to barite.

Doubts raised on ocean fertilization with iron

The ability of the ocean waters off Antarctica to absorb significant amounts of atmospheric carbon dioxide after fertilization with iron has been called into question by researchers who have modeled the dynamics of the process. Using a model calibrated with data on atomic bomb-produced radiocarbon in ocean waters, Wallace S. Broecker, of Columbia University's Lamont-Doherty Geological Observatory, Palisades, N.Y., and T.-H. Peng, of Oak Ridge National Laboratory, Oak Ridge, Tenn., calculate that 100 years of completely successful iron fertilization would reduce atmospheric C0 2 by only 10% [ Nature , 349 , 227 (1991)]. That is not enough, they say, to have a positive effect on projected global warming due to the greenhouse effect. The notion that the iron content of some large expanses of ocean determines the biological productivity of those waters was first proposed by John H. Martin, director of Moss Landing Marine Laboratories, Moss Landing, Calif. (C&EN, July 2, 1990, page 21). Martin has shown that ...

Distribution of Paleogene planktonic foraminifera — analogies with the Recent?

Distribution patterns and morphologies of modern and Paleogene planktonic foraminifera in the Atlantic Ocean were compared. Although many Paleogene and modern planktonic foraminifera are homeomorphs, they are not ecomorphs. Morozovellid homeomorphs of the modern higher spired globorotaliids inhabited warmest layers of the mixed layer. The planorotalitids, homeomorphic with modern low trochospiral globorotaliids, have different geographic ranges; they predominated at temperature and higher latitudes where they grew to largest sizes. The cool water low-spired subbotinids little resemble the non-spinose, modern neogloboquadrinids which dominate polar faunas today. Spinosity of Paleogene polar forms indicates that they could have been carnivorous or omnivorous, rather than herbivorous like the modern neogloboquadrinids. Early Paleogene polar seas may have been relatively oligotrophic for at least part of the year. Some Paleogene genera may have been ecomorphic with their modern analogues. The dentoglobigerinids and globoquadrinids occupied equatorial and offshore upwellings much as Neogloboquadrina dutertrei does today. Because the globorotaloids and catapsydracids deposited calcitic crusts and register most enriched oxygen isotope values, they may have lived within and below the thermocline like some modern globorotaliids. Globorotaloids and catapsydracids may have been strictly herbivorous as are most modern, non-spinose species. Their predominance in later Paleogene lower latitude upwellings, but their near exclusion from polar regions indicates that subeuphotic equatorial waters may have been more eutrophic. Paleogene-type warming (in Zones P1d, P3a, P5, P6–7, late P12, late P16, late P19, and early P22) involves proliferation, evolutionary diversification, and poleward migration of thermophilic forms, but decreased species abundance at low latitudes, and diminished numbers of fertility indices (the guembelitrids, biserial heterohelicids, globigerinathekids, globoquadrinids, or dentoglobigerinids). Neogene-type warmings (in Zones P4 and probably P alpha and P21a) involved diversification of cooler water taxa, retreat of thermophilic forms from higher latitudes and their concentration in lower latitudes, and proliferation of fertility indices. Under these conditions oxygen isotope records include lower latitude warming, but cooling of temperature and higher latitudes and tropospheric waters. Planktonic foraminiferal diversity and population structure reflect changes in oceanic fertility and the depth of the thermocline. Cooling and eutrophication resulting in a contraction of the TRC (Trophic Resource Continuum) in Atlantic surface waters from late middle Eocene through mid Oligocene time explain the low diversities, extinctions of morphologically complex thermophilic species, increased dominance of opportunistic, subeuphotic, and temperature species, proliferation of euphotic and subeuphotic fertility indices, and geographic expansion of siliceous primary producers.

Albian Pelagic Rhythms (Piobbico Core)

ABSTRACT The Piobbico core of Aptian-Albian pelagic rhythmites in Italy has been used to explore ways of extracting quantitative time-series of geological, chemical, physical and biological parameters from stratigraphic sequences. Recognition of the precession, obliquity, and eccentricity cycles (the Option frequencies) has permitted time-resolution to the 104-year level. Individually, these time-series curves furnish a potential basis for precise correlations. Collectively, they track the evolution of the depositional system in detail, including its response to orbital forcing. Orbital cycles primarily influenced oceanic fertility and carbonate productivity by foraminifera and coccoliths, as well as the aeration of bottom waters (redox cycle). Three short magnetic reversals occur w thin the Ticinella praeticinensis zone. Frequency spectra of variations in magnetic intensity, inclination and declination yield Milankovitch frequencies which are only partly explained as responses to mineralogy. A computer simulation used Berger's astronomically calculate precession index to drive 1) carbonate flux and 2) depth of bioturbation. This achieved a stratigraphy remarkably similar to that observed. Each step in the computer simulation transfers spectral power from precession to eccentricity. Work on the Piobbico core continues, while Project ALBICORE aims to explore the patterns of rhythmicity in the praeticinensis zone of other areas. End_Page 1164-----------------------

Iron in Antarctic waters

WE are testing the hypothesis that Antarctic phytoplankton suffer from iron deficiency1–3 which prevents them from blooming and using up the luxuriant supplies of major nutrients found in vast areas of the southern ocean. Here we report that highly productive4 (∼3 g C m−;2 day−1), neritic Gerlache Strait waters have an abundance of Fe (7.4 nmol kg−1) which facilitates phytoplankton blooming and major nutrient removal, while in low-productivity4 (∼0.1 g C m−2 day−1), offshore Drake Passage waters, the dissolved Fe levels are so low (0.16 nmol kg−1) that the phytoplankton are able to use less than 10% of the major nutrients available to them. The verification of present-day Fe deficiency is of interest as iron-stimulated phytoplankton growth may have contributed to the drawing down of atmospheric CO2 during glacial maxima2,3; it is also important because oceanic iron fertilization aimed at the enhancement of phytoplankton production may turn out to be the most feasible method of stimulating the active removal of greenhouse gas CO2 from the atmosphere, if the need arises (J.H.M., manuscript in preparation).

Ocean circulation and calcareous nannoplankton evolution during the jurassic and cretaceous

Spatial and temporal distribution of calcareous nannoplankton aid in the reconstruction of ocean circulation during the Cretaceous. Biogeographic patterns of calcareous nannoplankton during the late Cretaceous are mostly zonal, reflecting mostly latitudinal gradients of surface water temperature. During the middle Cretaceous calcareous nannofossil assemblages are more strongly affected by surface water fertility (concentration of limiting nutrients) especially in a wide tropical belt between 50° and 45°N latitudes. Major upwelling regions off northwest Africa, in the south Atlantic, and the equatorial Pacific divergence are apparent. Temporal changes in the composition of middle Cretaceous nannofloras are indicative of changes in surface water fertility and vertical mixing at frequencies of tens to hundreds of kiloyears (ka). Changes in the intensity of atmospheric circulation with frequencies close to the Milankovitch cycles appear to be the ultimate cause of these minor changes in the circulation of the upper ocean. Calcareous nannofossil preservation patterns show that during the Middle Cretaceous deep waters were quite homogeneous with respect to carbonate saturation in the Atlantic Ocean but not in the Indo-Pacific Ocean where a more distinctive calcite compensation depth (CCD) is apparent. Water-mass structure of the major oceans during the Mesozoic was thus quite different. Taxonomic evolution of calcareous nannofossils was also strongly affected by ocean circulation and fertility. Major peaks in the rates of diversification coincide with anoxic events, that is periods of increased preservation of organic carbon in the oceans which coincide with high sea level stands. During anoxic events ocean circulation was sluggish, vertical mixing was slow, deep ocean ventilation poor, and the concentration of limiting nutrients in surface waters was low. Increased competition for limiting nutrients and possibly preferential cropping of the dominant forms by zooplankton resulted in increased rates oof speciation during anoxic events. Periods of major production of nannofossil carbonate coincided with low sea-level stands when oceans were more vigorously stirred and surface waters were more fertile. The first such period was the latest Jurassic when calcareous nannoplankton invaded the open oceans and became the major carbonate producers in the pelagic realm during the Mesozoic. The frequency of peaks and troughs in evolutionary rates is on the order of 10–30 Ma and appears to be irregular. The coincidence of periods of anoxia with high sea-level stands, which in turn appear to be caused by more rapid sea-floor spreading indicates that the ultimate diving forces of nannoplankton evolution are processes in the earth's mantle. These major tectonically driven fluctuations in ocean-atmosphere circulation with frequencies of a few million to a few tens of millions of years are hereby named Fischer cycles. Superimposed astronomically driven Milankovitch cycles affected relative abundance patterns but not taxonomic evolution of calcareous nannoplankton. Rates of nannoplankton extinction are about five times higher than background rates at the end of the Jurassic and orders of magnitude higher in the latest Cretaceous possibly indicating a terrestrial or extraterrestrial catastrophe.

Mesozoic calcareous nannofossil evolution: Relation to paleoceanographic events

The taxonomic evolution of Jurassic and Cretaceous calcareous nannofossil species is described using the following indices: species diversity, rate of speciation, rate of extinction, rate of diversification, rate of turnover, survivorship, and species accretion. The Jurassic prior to the late Oxfordian is characterized by positive diversification rates, that is, rates of speciation exceeded rates of extinction. Highest rates of diversification occurred in the late Lias and early Oxfordian. During the generally regressive latest Jurassic, diversification rates remained low and rates of extinctions exceed rates of speciation. In the early Cretaceous, rates of diversification are positive and peak in the early Valanginian, early Aptian, and middle Albian, after which time rates of extinction generally exceed rates of speciation. Such peaks in rate of evolution coincide with times of increased accumulation of organic carbon in the ocean (“anoxic events”). Peaks in rates of extinction result in very high rates of turnover during times of major regressions, in particular, in the Tithonian and Maastrichtian. Survivorship analyses for three datum planes (74.5, 144, and 160 Ma) show relatively constant extinction rates with some stepping in the older part; they are best explained by a temporally fluctuating abiotic environment causing changes in the probability of extinction. Species accretion curves are also relatively linear with some indication of changing rates of speciation. The coincidences of major changes in evolutionary rates with major paleoceanographic events are indicative of a predominantly abiotic control of nannoplankton evolution. Relationships of evolutionary rates of calcareous nannoplankton with deep ocean ventilation, sea level, and ocean fertility indicates that global tectonic processes are the ultimate causes of evolutionary change.

Chronostratigraphic markers in the end-Precambrian carbon isotope record of the Lesser Himalaya

Early investigators1,2 noticed that the isotope age curve for sedimentary carbon contains a negative displacement in δ13C at the Precambrian/Cambrian (PC/C) boundary, about 570 million years ago3, which may have accompanied the profound biotic changes4 from non-skeletal organisms to those with mineralized skeletons. Whereas the certainty of the δ13C shift across the elusive boundary has recently been confirmed from a number of localities5–8, its interpretation remains largely controversial. It has been attributed to variations in oceanic biomass fertility and concomitant fluxes of organic matter burial6–8, changing rates of ocean ventilation9, onset of biomineralization10 and extraterrestrial causes5. Here we report the results of a carbon isotope study from a hitherto unexplored section of marine sediments in the Lesser Himalaya, India, which documents significant isotope variations across the PC/C boundary. These results also provide important details towards resolving the relative timing of the δ13C shifts and the biotic changes. Evaluation of our data rules out post-depositional isotope exchange as a major cause of the recorded δ13C variations and favours changes in the isotope chemistry of the ocean surface at the close of the Precambrian.

Sedimentary Record of Ancient Coastal Upwelling

of Part B.- Surface Sediment Distributions.- Some unique sedimentological and geochemical features of deposits in coastal upwelling regions.- Sedimentation of organic matter in upwelling regimes.- Biogenic sediments on the South West African (Namibian) continental margin.- The modern upwelling record off northwest Africa.- Biogenic sedimentary structures in a modern upwelling region: Northwest African continental margin.- Upwelling records in recent sediments from southern Portugal: A reconnaissance survey.- Environmental controls on sediment texture and composition in low oxygen zones off Peru and Oregon.- Coastal upwelling, its influence on the geotechnical properties and stability characteristics of submarine deposits.- Upwelling along the western Indian continental margin and its geological record: A summary.- High Resolution Holocene Time Scales.- Stable isotope record of upwelling and climate from Santa Barbara Basin, California.- Decadal variation of upwelling in the Central Gulf of California.- Oxygen isotope composition of diatom silica and silico-flagellate assemblage changes in the Gulf of California: A 700-year upwelling study.- Stable isotopes of foraminifers off Peru recording high fertility and changes in upwelling history.- Pleistocene Time Scales.- Spatial and temporal patterns of organic matter accumulation on the Peru continental margin.- Variability of upwelling regimes (northwest Africa, south Arabia) during the latest Pleistocene: A comparison.- Glacial-interglacial cycles in oceanic productivity inferred from organic carbon contents in eastern North Atlantic sediment cores.- Differentiation of high oceanic fertility in marine sediments caused by coastal upwelling and/or river discharge off northwest Africa during the late Quaternary.- Distribution of organic carbon in the Gulf of Alaska Neogene and Holocene sedimentary record.- Pre-Pleistocene Phanerozoic Time Scales.- Organic geochemistry of sediments recovered by DSDP/IPOD Leg 75 from under the Benguela Current.- Potential deep-sea petroleum source beds related to coastal upwelling.- Cretaceous upwelling off northwest Africa: A summary.- Facies patterns of a Cretaceous/Tertiary subtropical upwelling system (Great Syrian desert) and an Aptian/Albian boreal upwelling system (NW Germany).- Indications of upwelling in the Lower Ordovician of Scandinavia.- Upwelling in the Paleozoic era.- Paleozoic black shales in relation to continental margin upwelling.- Participants.

Deglacial CO 2 buildup: Constraints on the coral-reef model

The coral-reef hypothesis of degalcial CO 2 buildup in the atmosphere can account for about one-half of the signal seen in ice cores, assuming additional coral-reef growth releases 2 atmospheric carbon masses (ACM). The carbonate dissolution signal on the deep sea floor suggest titration of only 1 ACM. At least 4 ACM of CO 2 must be made available to satisfy the requirements of pCO 2-increases, growth of biosphere and of sedimentary carbon pool, carbonate dissolution on the sea floor, and saturation of newly introduced meltwater. A drop in ocean fertility is called for to provide the missing CO 2. Such a drop is evident in deep-sea cores from the western equatorial Pacific. CO 2 buildup appears to occur as a step, near 13,500 years B.P. Dissolution on the deep sea floor begins near 11,000 years B.P. The difference of 2500 years may describe a mixing lag due to meltwater input (the “Worthington Effect”).

Supply of Sediment to Oceans: Climate and Eustatic Sea Level Changes and Interregional Unconformities: ABSTRACT

The completeness of the deep-sea stratigraphic record depends upon the balance between sediment supply from biogenic surface production and delivery of detrital sediment across continental margins, and sediment removal by mechanical erosion and/or chemical dissolution. These parameters, in turn, are controlled by a combination of interrelated changes in global sea level, climate, and oceanography. Studies of the rates and patterns of accumulation of both biogenic and detrital sediment in the deep sea, based largely on data from DSDP drill holes, demonstrate that no single factor determines trends in deep-sea sedimentation. It is tempting to link the global patterns of rise and fall of End_Page 891------------------------------ sea level through time to trends in sedimentation in the oceans. For example, sea level lowstands are expected to result in increased supply of both detrital and chemical (biogenic) sediment to the deep sea. Thus, shelf unconformities, resulting from exposure and erosion of shelf sediments, should correlate with relatively high rates of sedimentation and low incidence of hiatuses in the deep sea. Global sea level highstands would have the opposite effect. The co-occurrence of widespread shelf and deep-sea unconformities, as found in the Oligocene and lower Paleocene contradicts such simple models. These and other examples show that terrigenous and biogenic sediment flux to deep-sea basins is not totally dependent on relative sea level, and that there are commonly significant time lags in the response of deep-sea sedimentation to changes in sea level and shelf sedimentation. Rates of rise and fall of sea level, however, are a major determining factor. Additionally, global and regional climate and overall patterns of oceanic circulation, fertility, and chemistry are equally important in controlling sediment supply to the deep sea and in the development of sedimentary lacunae in deep marine basins. End_of_Article - Last_Page 892------------

海水中での腸内細菌の消長に及ぼすし尿等の影響

Effect of digested night soil, marine plankton and light on the viable count of intestinal bacteria in the seawater were examined in order to estimate the sanitary problems of ocean fertilization with night soil. One hundred ml each of aged seawater with or without digested night soil (1%), phyto-plankton Nitzschia closterium, Phaeodactyllum tricornutum, Dunaliella tertiolecta, Brachiomonas sp., Chlamydomonas sp., Platymonas sp., Nannochloris sp. and Chlorella sp. and zooplankton Tigriopus japonicus, were inoculated wiht 108 cells per ml each of Escherichia coli, Salmonella typhimurium or Vibrio parahaemolyticus, and rotary shaken with or without illumination (ca. 6, 000lx) for several days at 20°C. Bacterial cells were counted every day by using selective media. In the dark and clean seawater, E. coli and S. typhimurium survived more than 6 and 15 days, respectively, and V. haemolyticus rather propagated. On the other hand, the former two species and the latter one died off within 1 and 3 days, respectively, in the illuminated seawater containing digested night soil and marine plankton.

The Magnetic Epoch-6 carbon shift: A change in the ocean's 13C/ 12C ratio 6.2 million years ago

Tropical Indian Ocean planktonic and benthic foraminifera have 13C/ 12C ratios which change abruptly within Magnetic Epoch 6 about 6.2 million years ago. All species analyzed in the Late Miocene section of DSDP Site 238 show a shift towards lighter values of δ 13C by about 0.8‰. The oxygen isotope signal indicates that the pre-shift period is climatically quiet while the post-shift period has strong fluctuations. We suggest that the shift reflects a sudden increase in the rate of supply of organic carbon from coastal lowlands and from shelves exposed by regression, as well as a change in deep circulation patterns and ocean fertility. The event marks the transition of the ocean—atmosphere system from a quiet Early and Middle Neogene climatic regime toward a Late Neogene regime characterized by climatic amplifying mechanisms (albedo feedback, bottom water production) located around the northern North Atlantic. The beginning of this regime may have been strongly influenced by the isolation of the Mediterranean basin.

Biogenous Sediments Recovered by Deep-Sea Drilling: ABSTRACT

The Deep Sea Drilling Project has provided about 60,000 m of cores that contain a record of biogenous sedimentation over a major part of the world ocean during the past 150 m.y. Subduction and subsidence bias the record in older strata toward sediments deposited near rise crests, and technical drilling problems bias the samples toward low latitudes. After factoring out the effects of plate motions and subsidence, the main features of maps of post-Jurassic biogenous facies reflect primarily the patterns of oceanic fertility and of dissolution of carbonates with depth. These in turn respond to changes in the interacting climate and the deep and surface oceanic circulation systems, which are ultimately determined by the changes in locations, shapes, and interconnections of t e ocean basins and their marginal seas. One great value of the cores is in their being samples whose biostratigraphic age is precisely known, whose paleolatitude, paleolongitude, and paleodepth can be specified, and whose pressure-temperature and pore-water history during burial and diagenesis generally can be far better constrained than for most sediments on land. Biostratigraphers and paleoenvironmentalists End_Page 553------------------------------ have been more active in exploiting these properties than have sedimentary petrologists interested in understanding the processes of diagenesis and lithification of calcareous and siliceous sediments. Lithologic criteria indicate very small volumes of oceanic biogenous sediments of post-Jurassic age are exposed on land, and it is questionable if any but relatively tiny amounts of any age have ever been added to the continents. End_of_Article - Last_Page 554------------

PROCEEDINGS OF THE GENERAL MEETING ON 13 October 1949

Prior to total exploitation in the mid-19th century, the principal guano islands of the Peruvian coast bore deposits of consolidated bird-droppings up to about 50 metres in thickness. The archaeological evidence assembled by Professor G. A. Kubler and the stratigraphic evidence brought together by the speaker indicate that this huge accumulation could have formed in a few thousand years. Prior to initiation of deposition on the Peruvian coast there was certainly much guano being laid down on the coast of, Chile, but farther north where the main deposits are formed to-day it is probable that the prevailing climatic regime was that of modern ‘abnormal’ wet years. In the central Pacific phosphatic guano deposits of post-glacial date and of large size, exceeding 10,000 tons, are confined to the area of low rainfall along the equator, within the zone of the South-East trade-winds and in the neighbourhood of the equatorial divergence. There is, however, reason to suppose that in such a region deposits of the size implied by the phosphate beds of Nauru, Ocean Island and some other localities in the Pacific, Christmas Island in the Indian Ocean and some West Indian Islands, could not have formed in a reasonable time. It is suggested that some huge deposits originated in periods of greatly enhanced oceanic fertility, due to a lowering of the vertical stability of the oceans when the supply of cold water was reduced during interglacials. The method used in plant-geographical analysis of a certain floristic area is the division of the plants in distributional units called ‘elements’. The term ‘element’ which was first introduced by H. Christ (1867) was subject to a large measure of conflicting interpretations. To mention only the misuse of the term ‘pontic element’ originally applied. by Kerner (1887) in a geographical sense, to designate the area of plants extending from the shores of the Black Sea to the Alps and Carpathians. This designation was used by subsequent investigators in an entirely different context, i.e. in a vegetational (steppe) ecological (heliophile), migratory (route) and in a historico-genetical respect (origin). The reason for these contradictions lies in the natural development of botanical science implying new plant-geographical approaches. The various authors include in the old singly existing term ‘element’ a variety of new plant-geographical aspects. The only suitable method of contending with these difficulties is to form adequate terms for each specialized aspect. In 1921 (Engler's Bot. Jahrb. 5: 598) Reichert suggested the use of the term ‘component’ for the designation of recent distribution, the term ‘migrant’ for migration of plants. He also desired to retain the old term‘ element’ for origin characterization in the sense of Engler (1878). In 1940 {Pal. Journ. of Bot., R.S., 8:183) Reichert proposed to revive the old name ‘type’ of Watson (1835) used by him for ecological description of plants for the same purpose. New proposals are now put forward for the characterization of a geographical natural area.