Cretaceous foraminifers from DSDP Hole 95-612

Site 612, located some 100 km southeast of Atlantic City in the northwest Atlantic Ocean, was cored to a total depth of 675.3 m below seafloor. The final 114.96 m recovered an Upper Cretaceous succession that can be assigned to the late Campanian and early Maestrichtian. The dark mudstones of Campanian age contain an impoverished fauna of planktonic foraminifers, while the paler, nannofossil chalks of Maestrichtian age contain a typically diverse planktonic fauna. The environment represented by the Campanian fauna indicates the presence of slightly anoxic water in the vicinity of the New Jersey Slope at that time

Distribution of ostracoda in the lower Cretaceous succession of ODP Hole 80-549 (Figure 3)

Site 549 recovered a Lower Cretaceous succession which has been shown to include parts of the Barremian and Albian stages. Forty-four species of Ostracoda are illustrated and their stratigraphic distribution used to recognise three major facies units. An high diversity inner shelf facies earlier in the Barremian gives way to a low diversity, outer shelf facies, higher in the succession. The early Albian appears to indicate a return to an inner shelf fauna. The faunas recovered have been compared to similar faunas elsewhere in N. W. Europe

Stable oxygen and carbon isotope ratios for Early to Middle Cretaceous benthic and planktonic foraminifera of DSDP Hole 62-463 from the Mid Pacific Mountains (Table 1)

Stable isotopic measurements have been made on planktonic and benthic foraminifera of Early to mid-Cretaceous (Early Albian-Cenomanian) age from DSDP site 463 located in the Pacific Ocean. The degree of alteration of the foraminifera has been assessed through the application of scanning electron microscopy. The oxygen isotope data support the view that during the Cenomanian 'globigerine' foraminifera, such as the genus Hedbergella, inhabited near-surface waters, whilst the flattened, keeled, morphotypes lived deeper within the water column. The carbon isotope data reveal a more complex pattern as the delta13C values from planktonic species essentially show a large overlap, which is interpreted in terms of a weak delta13C gradient existing in the upper part of the ocean. In contrast, the oxygen isotope data from planktonic foraminifera from the Late Albian display no discernible depth stratification pattern and the delta13C data also show a large overlap of values indicative of a complete disruption of the upper part of the thermocline. A relatively low surface to bottom water temperature gradient within the Early-Middle Albian part of the succession may reflect a well-mixed ocean. Inferred cool ocean temperatures (and/or high salinities) for the Early Albian may reflect increased oceanic poleward heat transport. An increase in temperature (and/or decrease in salinity) in the Cenomanian suggests a reduction of the poleward heat flux, promoting the build-up of limited polar ice during this period of tropical warmth

Foraminifera species in the CO2 vents near Ischia, Italy, 2010

The seas around the island of Ischia (Italy) have a lowered pH as a result of volcanic gas vents that emit carbon dioxide from the sea floor at ambient seawater temperatures. These areas of acidified seawater provide natural laboratories in which to study the long-term biological response to rising CO2 levels. Benthic foraminifera (single-celled protists) are particularly interesting as they have short life histories, are environmentally sensitive and have an excellent fossil record. Here, we examine changes in foraminiferal assemblages along pH gradients at CO2 vents on the coast of Ischia and show that the foraminiferal distribution, diversity and nature of the fauna change markedly in the living assemblages as pH decreases

Annotated record of the detailed examination of Mn deposits from DSDP Leg 95 (Holes 612 and 613)

Baltimore Canyon Trough, the most intensely studied offshore sedimentary basin of the U.S. Atlantic margin, encompasses the coastal plain, continental shelf, and continental slope of New Jersey, Delaware, Maryland, and (in part) Virginia. On the basis of the extensive published record of the geological and geophysical investigations of this area, the New Jersey margin was chosen as the most suitable location for constructing the first marginwide stratigraphic transect. As envisioned, the transect would extend from the outcrop belt in central New Jersey to a location 700 km distant on the lower continental rise. Initial Deep Sea Drilling Project (DSDP) core holes on the slope and upper rise would emphasize the Cenozoic and Upper Cretaceous sections, as dictated by the limitations of openhole drilling. Leg 95 was principally intended to provide a crucial link between shelf and lower rise sites which had been cored along the transect during Leg 93

Benthic foraminiferal assemblage counts from the Gulf of California

Extensive CO2 vents have been discovered in the Wagner Basin, northern Gulf of California, where they create large areas with lowered seawater pH. Such areas are suitable for investigations of long-term biological effects of ocean acidification and effects of CO2 leakage from subsea carbon capture storage. Here, we show responses of benthic foraminifera to seawater pH gradients at 74-207 m water depth. Living (rose Bengal stained) benthic foraminifera included Nonionella basispinata, Epistominella bradyana and Bulimina marginata. Studies on foraminifera at CO2 vents in the Mediterranean and off Papua New Guinea have shown dramatic long-term effects of acidified seawater. We found living calcareous benthic foraminifera in low pH conditions in the northern Gulf of California, although there was an impoverished species assemblage and evidence of post-mortem test dissolution