Benthic foraminifera in surface sediments of the Arabian Sea

Assemblages of living deep-sea benthic foraminifera, their densities, vertical distribution pattern, and diversity, were investigated in the intermonsoon period after the northeast monsoon in the Arabian Sea in spring 1997. Foraminiferal numbers show a distinct gradient from north to south, with a maximum of 623 foraminifera in 50 cm**3 at the northern site. High percentages of small foraminifera were found in the western and northern part of the Arabian Sea. Most stations show a typical vertical distribution with a maximum in the first centimeter and decreasing numbers with increasing sediment depths. But at the central station, high densities can be found even in deeper sediment layers. Diversity is very high at the northern and western sites, but reduced at the central and southern stations. Data and faunal assemblages were compared with studies carried out in 1995. A principal component analysis of intermonsoon assemblages shows that the living benthic foraminifera can be characterized by five principal component communities. Dominant communities influencing each site differ strongly between the two years. In spring 1997, stations in the north, west and central Arabian Sea were dominated by opportunistic species, indicating the influence of fresh sedimentation pulses or enhanced organic carbon fluxes after the northeast monsoon.

Planktonic foraminifera in the Maastrichtian of Hor-Hahar

The lengthy warm, stable climate of the Cretaceous terminated in the Campanian with a cooling trend, interrupted in the early and latest Maastrichtian by two events of global warming, at ~70-68 Ma and at 65.78-65.57 Ma. These climatic oscillations had a profound effect on pelagic ecosystems, especially on planktic foraminiferal populations. Here we compare biotic responses in the tropical-subtropical (Tethyan) open ocean and mesotrophic (Zin Valley, Israel) and oligotrophic (Tunisia) slopes, which correlate directly with global warming and cooling. The two warming events coincide with blooms of Guembelitria, an extreme opportunist genus best known as the main survivor of the Cretaceous-Paleogene (K-Pg) catastrophe. In the Maastrichtian, Guembelitria bloomed in the uppermost surface water above shelf and slope environments but failed to reach the open ocean as it did at K-Pg. The coldest interval of the late Maastrichtian (~68-65.78 Ma) is marked by an acme of the otherwise rare species Gansserina gansseri, a deep-dwelling keeled globotruncanid. The G. gansseri acme event can be traced from the deep ocean even onto the Tethyan slope, marking copious production and circulation of cold intermediate water. This acme is abruptly terminated by extinction of the species, a dramatic reversal attributed to a short-term global warming episode. This extinction corresponds precisely with the second bloom of Guembelitria that began ~300 kyr prior to the K-Pg event. The antithetical relationship between blooming of Guembelitria and the G. gansseri acme reflects planktic foraminiferal sensitivity to warm-cool-warm-cool climatic oscillations marking the end of the Cretaceous.

Assamblages and cluster analysis from DSDP Hole 22-214 of the eastern Indian Ocean

Multivariate analyses of latest Pliocene through Holocene benthic foraminifera from 61 samples from Deep-Sea Drilling Project (DSDP) Site 214, eastem Indian Ocean were carried out. The 46 highest ranked species were used in R-mode factor analysis which has enabled to the identification of three environmentally significant assemblages at Site 214. Assemblage 1 is characterized by Uvigerina hispido-costata, Osangularia culter , Gavelinopsis lobatulus, Cibicides wuellerstorfi and Karreriella baccata as principal species. This assemblage is inferred to reflect high-energy, well-oxygenated and probably low-organic carbon deep-sea environment at Site 214. Assemblage 2 is defined principally by Globocassidulina pacifica and U. proboscidea and is considered to indicate an organic carbon-rich environment which resulted from high surface productivity irrespective of dissolved oxygen content. Assemblage 3 is marked by Oridorsalis umbonatus, Textularia lythostrota, Hoeglundina elegans, Pyrgo murrhina, and Pullenia quinqueloba as principal species. This assemblage is inferred to indicate a low-organic carbon environment with high pore water oxygen concentration leading to better preservation of deep-sea sediments.

El secreto del análisis

El presente trabajo se abocara a estudiar la trasnferencia como fenómeno y la operación del analista en esta, ya que la dirección de la cura se hace en transferencia. Freud se fue encontrando en su experiencia clínica con la transferencia como una herramienta de la cura para determinar desde donde es demandado y escuchado el analista, desde donde es incluido en el conflicto neurótico. Al principio, se le atribuye a Freud operar desde un lugar de amo que paulatinamente revela el surgimiento del deseo del analista, noción que tendra que esperar a Lacan para su conceptualización. Así, Freud concibo a la transferencia como repetición, resistencia y motor de la cura, ontraindicando se intervenga por la vertiente sugestiva que también esta presente en la transferencia.Posteriormente, se necesitara del retorno de Lacan a la obra freudiana para que esta orientación sea nuevamente interrogada y el concepto de transferencia recupere su estatuto original. Lacan sitúa la transferencia al nivel de la estrategia ya que todo acto del analista tiene efecto por la posición que éste ocupa como lugar simbólico, es decir, en dependencia con el fantasma del analizante. Entonces, el analista dirige la cura, operando desde el lugar que ocupa, pero no al paciente. Dirigir la cura supone aplicar la regla fundamental de libre asociación, aunque ésta no lo es tanto ya que esta sujeta al deseo del analista. Así, el lugar que ocupe el analista como soporte de la transferencia esta fundado en el deseo del analista, es decir, en su ética. Es objetivo de esta propuesta determinar cual es la ética y, por ende, el deseo desde el cual opera el analista en la cura, en tanto nos permitira delimitar la dirección que tomara ésta y los posibles destinos de un sujeto intervenido, en un dispositivo donde la transferencia y el uso que de ella se hace, constituye una pieza clave. Para esto se establecera una distinción entre dos tipos de respuesta posibles a la demanda de análisis de un sujeto: - Algunos posfreudianos que afirmaron que el yo se encuentra debilitado por el conflicto y el analista debe acudir en auxilio de este yo, por lo tanto la acción debe orientarse hacia la realización de una reeducación emocional, lo que implicaría atribuirse, el propio terapeuta, un saber sobre lo que es mejor para el otro. El terapeuta resultaría funcional con la ética que rige el malestar en la cultura, conduciendo al malestar del deseo a través de su renuncia. - Por otro lado, Lacan que articulando la vertiente simbólica de la cadena significante con el goce del objeto a través del amor de transferencia posibilitara al analista operar sobre lo real a través de lo simbólico.De este modo, el analista opera desde el lugar que le da la transferencia del analizante, estando sostenida su presencia por el Otro simbólico del paciente. Como agalma puede captar el deseo del sujeto prestándose para cumplir esta función, sabiendo que enmascara el objeto que esta en causa para el analizante. Si esta operando el deseo del analista, el analizante podra localizar su deseo a partir de la falta de su signo en el Otro. En este caso, la ética en juego es una ética del deseo: el psicoanálisis se orienta del malestar al saber hacer con el síntoma, pasando por el deseo. Concluyendo, estas dos respuestas conducen hacia destinos con efectoscontrapuestos en la vida de un sujeto. Ambas derivaron de la lectura de la obra freudiana: una que perdió el sentido de su descubrimiento, otra que lo retomo. Entonces, la distinción radical que realiza el psicoanálisis entre el Otro del significante y el objeto a, obstaculiza toda posibilidad de asentar el dispositivo analítico en unacomunicación interpersonal. La identificación que favorece toda comunicación interpersonal es desalentada por el deseo del analista como función que empuja a la posición deseante, al más allá del amor de transferencia, donde el analista ofrece su presencia para que el objeto a adquiera su posición de semblante y reconduzca a la pulsión, posibilitando que el analizante pueda encontrarse con sus puntos de goce y hacer de ellos otra cosa que le implique menos sufrimiento. Que el analizante pueda encontrarse con que la falta es estructural e inherente a todo sujeto del lenguaje

Benthic foraminiferal fauna and isotope record in Holocene sediments of the northwest Indian Ocean

Historically, the Holocene has been considered an interval of relatively stable climate. However, recent studies from the northern Arabian Sea (Netherlands Indian Ocean Program 905) suggested high-amplitude climate shifts in the early and middle Holocene based on faunal and benthic isotopic proxy records. We examined benthic foraminiferal faunal and stable isotopic data from Ocean Drilling Program (ODP) Site 723 and total organic carbon data from ODP Site 724, Oman Margin (808 and 593 m water depths, respectively). At Site 723 the mid-Holocene shift in d18O values of infaunal benthic species Uvigerina peregrina (1.4 per mil) is 3 times larger than that of epifaunal benthic species Cibicides kullenbergi recorded at Site NIOP 905 off Somalia. However, none of the five other benthic species we measured at Hole 723A exhibits such a shift in d18O. We speculate that the late Holocene d18O decrease in U. peregrina represents species-specific changes in ecological habitat or food preference in response to changes in surface and deep ocean circulation. While the stable isotopic data do not appear to indicate a middle Holocene climatic shift, our total organic carbon and benthic faunal assemblage data do indicate that the early Holocene deep Arabian Sea was influenced by increased ventilation perhaps by North Atlantic Deep Water and/or Circumpolar Deep Water incursions into the Indian Ocean, leading to remineralization of organic matter and a relatively weak early Holocene oxygen minimum zone in the northwest Arabian Sea in spite of strong summer monsoon circulation.

Cretaceous and Paleogene calcareous nannofossils from ODP Leg 123

Two of five holes drilled at two separate sites during Leg 123 of the Ocean Drilling Program intersected thick and relatively complete sections of Upper Cretaceous-Paleogene nannofossiliferous sediments. Although dominated by turbidite deposition in the upper part, Hole 765C contains a thick and relatively complete Albian-Oligocene section, including a particularly thick Aptian interval, with abundant and fairly well-preserved nannofossils. Several unconformities are confidently interpreted in this section that span much of the Santonian, late Campanian, Maestrichtian, late Eocene, and early Oligocene. Hole 766A contains a thick and relatively complete Albian-lower Eocene section having generally abundant and well-preserved nannofossils. Several unconformities also have been identified in this section that span much of the Coniacian, early Campanian, Maestrichtian, and late Eocene through early Pliocene. The chronostratigraphic position and length of all these unconformities may have considerable significance for reconstructing the sedimentary history and for interpreting the paleoceanography of this region. A particularly thick section of upper Paleocene-lower Eocene sediments, including a complete record across the Paleocene/Eocene boundary, also was cored in Hole 766A that contains abundant and diverse nannofossil assemblages. Although assemblages from this section were correlated successfully using a standard low-latitude zonation, difficulties were encountered that reduced biostratigraphic resolution. Several lines of evidence suggest a mid-latitude position for Site 766 during this time, including (1) high assemblage diversity characteristic of mid-latitude zones of upwelling and (2) absence of certain ecologically controlled markers found only in low latitudes.

Benthic foraminiferal composition at the inner wall of the Middle America Trench, Costa Rica

The sediments of Deep Sea Drilling Project Site 565 and University of Texas Marine Science Institute Cores IG-24-7-38 to -42 taken on the landward slope of the Middle America Trench exhibit characteristics of material subject to reworking during downslope mass flow. These characteristics include a generally homogeneous texture, lack of sedimentary structures, pervasive presence of a penetrative scaly fabric, and presence of transported benthic foraminifers. Although these features occur throughout the sediments examined, trends in bulk density, porosity, and water content, and abrupt shifts in these index physical properties and in sediment magnetic properties at Site 565 indicate that downslope sediment creep is presently most active in the upper 45 to 50 m of sediment. It cannot be determined whether progressive dewatering of sediment has brought the material at this depth to a plastic limit at which sediment can no longer flow (thus resulting in its accretion to the underlying sediments) or whether this depth represents a surface along which slumping has occurred. We suspect both are true in part, that is, that mass movements and downslope reworking accumulate sediments in a mobile layer of material that is self-limiting in thickness.

Mid-Pleistocene benthic foraminiferal record in the Southwest Pacific

Benthic foraminiferal faunas from three bathyal sequences provide a proxy record of oceanographic changes through the mid-Pleistocene transition (MPT) on either side of the Subtropical Front (STF), east of New Zealand. Canonical correspondence analyses show that factors related to water depth, latitude and climate cycles were more significant than oceanographic factors in determining changes in faunal assemblage composition over the last 1 Ma. Even so, mid-Pleistocene faunal changes are recognizable and can be linked to inferred palaeoceanographic causes. North of the largely stationary STF the faunas were less variable than to the south, perhaps reflecting the less extreme glacial-interglacial fluctuations in the overlying Subtropical Surface Water. Prior to Marine Isotope Stage (MIS) 21 and after MIS 15, the northern faunas had fairly constant composition, but during most of the MPT faunal composition fluctuated in response to climate-related food-supply variations. Faunal changes through the MPT suggest increasing food supply and decreasing dissolved bottom oxygen. South of the STF, beneath Subantarctic Surface Water, mid-Pleistocene faunas exhibited strong glacial-interglacial fluctuations, inferred to be due to higher interglacial nutrient supply and lower oxygen levels. The most dramatic faunal change in the south occurred at the end of the MPT (MIS 17- 12). with an acme of Abditodentrix pseudothalmanni, possibly reflecting higher carbon flux and lower bottom oxygen. This study suggests that the mid-Pleistocene decline and extinction of a group of elongate, cylindrical deep-sea foraminifera may have been related to decreased bottom oxygen concentrations as aresult of slower deep-water currents.