Primary productivity and mass fluxes for four stations in teh equatorial Pacific (Table 1)

Primary productivity (14C) and mass flux measurements using a free-drifting sediment trap deployed at 900 m were made at four stations in the Pacific Ocean between 12°N and 6°S at 153°W. The latitudinal variations in productivity were consistent with historical patterns showing the equator as a zone of high production and the oligotrophic waters north of the equatorial region as an area of low productivity. The correlation coefficient between the two sets of independent measurements was 0.999, indicating that in this oceanic area the activity of the primary producers was closely related to the total mass flux. A re-examination of historical data suggests that the downward flux of particulate organic carbon varies in direct proportion to the quotient of surface primary production raised to the 1.4 power and depth raised to the 0.63 power.

Calcareous dinoflagellates in the eastern equatorial Atlantic

Sediments of the Equatorial Atlantic (core GeoB 1105-4) have been investigated for both calcareous dinoflagellates and organic-walled dinoflagellate cysts. In order to determine the ecological affinity of calcareous dinoflagellates the statistical methods of Detrended Correspondence Analysis (DCA) and Redundancy Analysis (RDA) were used. Utilising DCA, distribution patterns of calcareous dinoflagellates have been compared with those of the ecologically much better known organic-walled dinoflagellate cysts. This method was also used to determine which environmental gradients have a major influence on the species composition. By using existing environmental information based on benthic and planktic foraminifera, such as Sea Surface Temperature (SST) and stable oxygen and carbon isotopes, as well as information on the amount of Calcium Carbonate and Total Organic Carbon (TOC) in bottom sediments, these gradients could be interpreted in terms of productivity and glacial-interglacial trends. Using RDA, the direct relationships between the distribution patterns of calcareous dinoflagellates with the above mentioned external variables could be determined. For the studied region and time interval (141-6.7 ka) the calcareous dinoflagellates show enhanced abundances in periods with reduced productivity most probably related to decreased divergence and relatively stratified, oligotrophic oceanic conditions.

(Table 2) Radiocarbon ages of eastern equatorial Pacific sediment cores

We use planktonic oxygen isotope (d18O) records spanning the last 30,000 years (kyr) to constrain the magnitude and spatial pattern of glacial cooling in the upwelling environment of the eastern equatorial Pacific (EEP). Fourteen new downcore d18O records were obtained from surface-dwelling planktonic foraminifera Globigerinoides sacculifer and Globigerinoides ruber in eight cores from the upwelling tongue of the EEP. All sites have sedimentation rates exceeding 5 cm/kyr and, with one exception, lie above the modern depth of the foraminiferal lysocline. Sites directly underlying the cool band of upwelling immediately south of the equator record mean late Holocene (LH)-Last Glacial Maximum (LGM) d18O amplitudes ranging between 1.0 and 1.3 per mil. We estimate that mean sea surface temperatures (SST) in this region during the LGM were on average 1.5 ± 0.5°C lower than the LH. Larger d18O amplitudes are observed in sites north of the equator, indicating a spatial pattern of reduced meridional SST gradient across the equator during the LGM. This result is supported by comparison of Mg/Ca SST reconstructions from two sites straddling the equator. We interpret the reduction of this gradient during the LGM as evidence for a less intense cold tongue-Intertropical Convergence Zone (ITCZ) frontal system, a more southerly position of the ITCZ, and weaker southeast equatorial trades in the EEP.

Short-term variations in radiolarian faunal dsitribution in the eastern equatorial Pacific

Two short time intervals centered at 2.3 and 4.7 Ma were studied to investigate short-term variations in surface-ocean processes as indicated by changes in the radiolarian microfossil population. These time intervals represent two different settings of late Neogene climate. The older interval represents a time when tropical circulation between the Pacific and Atlantic oceans was not blocked by the Isthmus of Panama, whereas the younger interval represents a time when Northern Hemisphere glaciation was present but did not display the dominance of the 100,000-yr cycle that characterizes the late Pleistocene. The younger time slice at 2.3 Ma was sampled at all Leg 138 sites except Site 844, where significant reworking was evident. All sites except 844, 853, and 854 were sampled for the older time slice. Samples were taken at 10- to 20-cm intervals at each site and spanned a GRAPE density maximum and minimum. Thus, it was possible to investigate whether the changes in carbonate content (as indicated by GRAPE density) were associated with changes in surface-ocean conditions (indicated by radiolarian assemblage variations). For both time slices, the radiolarian data indicate that intervals of decreased carbonate content are periods of cooler water conditions and possibly enhanced biogenic production. Times of increased carbonate content are associated with inferred warmer oceanographic conditions, as indicated by the dominance of tropical assemblages at 2.3 Ma and tropical and western Pacific assemblages during the time slice centered at 4.8 Ma. However, the spatial patterns of change during each time slice show a distinct difference in the mapped patterns of radiolarian assemblage dominance. The older time slice, representing a period before the closing of the Isthmus of Panama, shows more zonal patterns presumably associated with a more zonal character of equatorial circulation. After the closing of the isthmus, the shifts in faunal patterns between times of high and low carbonates are characterized by shifts in the dominance of the tropical and transitional assemblages, respectively, throughout the region.

Late Eocene to Recent deep-sea benthic foraminifera from the Central equatorial Pacific Ocean

Benthic foraminifers were studied in upper Eocene to Recent core-catcher samples from DSDP Sites 573, 574, and 575. The sites are on a north-south transect from the equator to about 05°N at about 133°W, water depth 4300 to 4600 m. At Site 574 additional samples were used to study the Eocene/Oligocene boundary in detail. About 200 specimens were counted per sample. The fauna is highly diverse (about 50 to 70 species per sample) and is of low dominance. The diversity is not related to age or sub-bottom depth. Many species are cosmopolitan and probably have wide environmental tolerances. Fluctuations in frequency of some taxa (e.g., Nuttallides umbonifera, Epistominella exigua, and Uvigerina spp.) cannot be correlated from one site to another. Several common species (e.g. Oridorsalis umbonatus and Globocassidulina subglobosa) range from late Eocene to Recent. First and last appearances are generally difficult to define precisely because many species are rare. For some species these datums differ from one site to another, but several datum levels are within 1 m.y. at all sites. First and last appearances are most numerous in two intervals, the late Eocene to early Oligocene (about 32 to 37 Ma) and the early to middle Miocene (about 13 to 18.5 Ma). Isotopic events occur within each of these periods of benthic faunal change, but the isotopic events have a shorter duration and start after the initiation of the changes in the fauna. Changes in deep-sea benthic faunal composition are not directly related to short-term oceanographic changes as expressed in isotopic records.

Stable oxygen isotope record of planktonic foraminifera from late Quaternary sediments of the equatorial Pacific

Planktonic foraminiferal test fragmentation in three cores along a depth transect from the western equatorial Pacific (ERDC-93P, 1619 m; RC17-177, 2600 m; V28-238, 3120 m [Thompson, 1976]) were examined for the last 500 kyr at sample intervals from 2.5 to 5 kyr to study the fluctuations of dissolution in the western equatorial Pacific. The age models were constructed by correlating the delta18O records with the SPECMAP stack [Imbrie et al., 1984]. Results showed that intermediate and deep waters experienced the same patterns of dissolution through climatic cycles. Fragmentation varied with a greater amplitude, and the carbonate ion concentration changed less, in the deep than in the intermediate water. Dissolution has significant variance distributions and coherencies with delta18O over the 100, 41, and 23 kyr periods of orbital variations; dissolution maxima lag ice volume minima by 6 to 20 kyr. The dissolution variability was consistent with recent geochemical models which seek to explain the reduction of atmospheric CO2 concentration at the last glacial maximum [Broecker, 1982; Boyle, 1988].

(Table 1) Sea surface temperature reconstruction for eastern equatorial Pacific surface sediment samples

Significant uncertainties persist in the reconstruction of past sea surface temperatures in the eastern equatorial Pacific, especially regarding the amplitude of the glacial cooling and the details of the post-glacial warming. Here we present the first regional calibration of alkenone unsaturation in surface sediments versus mean annual sea surface temperatures (maSST). Based on 81 new and 48 previously published data points, it is shown that open ocean samples conform to established global regressions of Uk'37 versus maSST and that there is no systematic bias from seasonality in the production or export of alkenones, or from surface ocean nutrient concentrations or salinity. The flattening of the regression at the highest maSSTs is found to be statistically insignificant. For the near-coastal Peru upwelling zone between 11-15°S and 76-79°W, however, we corroborate earlier observations that Uk'37 SST estimates significantly over-estimate maSSTs at many sites. We posit that this is caused either by uncertainties in the determination of maSSTs in this highly dynamic environment, or by biasing of the alkenone paleothermometer toward El Niño events as postulated by Rein et al. (2005).

Geochemistry and microfossil content of surface sediments from the Equatorial Atlantic in samples 207 to 310 from the Meteor expedition in 1925

Als Alfred Merz mich aufforderte, die sedimentpetrographische Bearbeitung der "Meteor"-Expedition zu übernehmen, schwebte mir von vornherein als Ziel vor, die Sedimente nicht nur in größerer Zahl als bisher und im Zusammenhang mit den übrigen Wissenschaften vom Meer nach den bisherigen Untersuchungsmethoden zu beschreiben. Es war mir klar, daß neue Ergebnisse nur zu erwarten waren, wenn die Untersuchung der Sedimente und damit ihre Beschreibung auf Grund vertiefter und neuer Methoden unternommen wurde. Ich erhoffte von einer solchen verfeinerten Beschreibung auch ein klareres Bild der Abhängigkeit der Sedimente von ihrer Umwelt. Wir werden diese Abhängigkeit nur verstehen, wenn wir die allgemeinen Gesetzmäßigkeiten herausarbeiten können. Diese werden dann auch eine Anwendung auf andere Sedimente ermöglichen. Für solche Untersuchungen sind Tiefseesedimente günstig, weil wir bei ihnen relativ einfache Bildungsumstände haben, einfacher jedenfalls, als es in der Flachsee im allgemeinen der Fall ist, ungünstig aber, weil diese Umwelteinflüsse weniger bekannt und schwerer zu erforschen sind und die Auswahl der Untersuchungspunkte nicht nach sedimentpetrographischen Gesichtspunkten erfolgen konnte. Die ersten Jahre nach der Rückkehr von der Expedition wurden deshalb auf methodische Untersuchungen verwandt. Insbesondere kam es mir darauf an herauszubekommen, wie die feinsten Bestandteile der Sedimente zusammengesetzt sind. Diese "tonigen" Bestandteile bilden nicht nur den wesentlichen Anteil der Roten Tone und der Blauschlicke, wir finden sie auch, durch Kalk verdünnt, in den Globigerinenschlämmen wieder. Sie sind von der Wissenschaft bisher recht stiefmütterlich behandelt worden. Die Ausarbeitung der Methoden, die gerade auf diesem Gebiet Neuland betreten mußte, ließ sich nicht rasch erzwingen. Es kam hinzu, daß ich mir in Rostock erst meine Arbeitsmöglichkeiten schaffen mußte. Ich habe hier der Notgemeinschaft der Deutschen Wissenschaft und der Mecklenburgischen Regierung für ihre Unterstützung mit Apparaten und Personal wärmstens zu danken. Ferner mußte als Vorbedingung für die Deutung der Sedimente zunächst festgestellt werden, zu welchen geologischen Zeiten sie gebildet worden sind und wie groß ihre Bildungsgeschwindigkeit überhaupt ist. Diese Untersuchungen hat W. Schott mit Hilfe der Foraminiferenfaunen als Notgemeinschaftsstipendiat durchgeführt. Diese Vorarbeiten, insbesondere der Ausbau der Methoden, hatten den Nachteil, daß die Veröffentlichung der Ergebnisse nicht so rasch erfolgen konnte, wie ich es selbst gewünscht hätte. Bald nachdem die Darstellung der Methoden und die Foraminiferenuntersuchungen als erste Lieferung erschienen waren, stellte es sich als notwendig heraus, eine beträchtliche Kürzung des restlichen Teiles vorzunehmen. Das hat zur Folge, daß die erste Lieferung breiter dargestellt ist als die Ergebnisse. Als die Nachricht von der Kürzung und dem notwendigen raschen Abschluß des Werkes mir bekannt wurde (Januar 1935), mußte eine Reihe von Untersuchungen eingestellt werden, insbesondere mikroskopische Untersuchungen, die besonders viel Zeit und in der Darstellung viel Raum beanspruchen. Deshalb ist systematisch nur das Guinea-Becken durch V. Leinz und das Kapverden-Becken durch O. E. Radczewski untersucht worden.

Equatorial Pacific Ocean climate studies (EPOCS) : progress and plans.

"October 1985".

Orbits of the double stars, A B of [Epsilon] Hydrae and ? 883, by the graphical method.

Type-written ms.

Tables for rocket and comet orbits /

Bibliography: p. xxiii.

Particle orbits in the static sheet pinch /

"April 1963."

Explorations and adventures in equatorial Africa : with accounts of the manners and customs of the people, and of the chace of the gorilla, the crocodile, leopard, elephant, hippopotamus and other animals /

First published 1861.

James Hannington, D.D., F.L.S., F.R.G.S. first bishop of eastern equatorial Africa; a history of his life and work, 1847-1885

Mode of access: Internet.

Equatorial Guinea, post report.

Mode of access: Internet.