Syracosphaera azureaplaneta sp. nov. and revision of Syracosphaera corolla Lecal, 1966

Here we show that the extant coccolithophore Syracosphaera corolla Lecal, 1966 comprises two consistently different non-intergrading morphotypes characterised respectively by exothecal coccoliths with wide and narrow central-areas. These are interpreted as separate species and so a new species is described, S. azureaplaneta, and a revised description is given for S. corolla

Investigating the persistence of tick-borne pathogens via the R0 model

In the epidemiology of infectious diseases, the basic reproduction number,R0, has a number of important applications, most notably it can be used to predict whether a pathogen is likely to become established, or persist, in a given area. We used the R0 model to investigate the persistence of 3 tick-borne pathogens; Babesia microti, Anaplasma phagocytophilum and Borrelia burgdorferi sensu lato in an Apodemus sylvaticus-Ixodes ricinus system. The persistence of these pathogens was also determined empirically by screening questing ticks and wood mice by PCR. All 3 pathogens behaved differently in response to changes in the proportion of transmission hosts on which I. ricinus fed, the efficiency of transmission between the host and ticks and the abundance of larval and nymphal ticks found on small mammals. Empirical data supported theoretical predictions of the R0 model. The transmission pathway employed and the duration of systemic infection were also identified as important factors responsible for establishment or persistence of tick-borne pathogens in a given tick-host system. The current study demonstrates how the R0 model can be put to practical use to investigate factors affecting tick-borne pathogen persistence, which has important implications for animal and human health worldwide

Stratigraphy around the Cretaceous-Paleogene boundary in sediment cores from the Lord Howe Rise, Southwest Pacific

During Deep Sea Drilling Project (DSDP) Leg 21, Cenozoic and latest Cretaceous sediments were recovered at Site 208 on the Lord Howe Rise, Southwest Pacific. We provide new biostratigraphic, magnetostratigraphic and chemostratigraphic data from Site 208 to constrain the stratigraphy around the Cretaceous-Paleogene (K-Pg) boundary and to determine the depth of the K-Pg boundary more precisely. Biostratigraphic data from calcareous nannofossils indicate a near-continuous succession of sediments from the mid-Maastrichtian (Late Cretaceous) to lowermost Thanetian (Paleocene) at depths of 540−590 m below seafloor (mbsf). The biostratigraphic data suggest that the K-Pg boundary corresponds to a siliceous claystone at the base of an interval of silicified sediments (576.0−576.8 mbsf). Carbonate carbon isotopic composition (δ^{13}_{Ccarb}) reveals a negative shift across this interval, which is consistent with global patterns of δ^{13}C across the K-Pg boundary. Osmium concentration and Os isotopic composition ({187}^Os/{188}^Os) can also be used to identify the K-Pg boundary interval, as it is marked by a peak in Os concentration and a drop in 187^{Os}/{188}^Os values to 0.12−0.15, both of which are the result of the Chicxulub impact event. Our {187}^Os/{188}^Os data show trends similar to those of coeval global seawater with the lowest value of 0.12−0.16 in the siliceous claystone (576.8 mbsf). However, the concentration of Os is low (<80 pg g^{−1}) in this sample, which suggests that this siliceous claystone was deposited around the K-Pg boundary but may not include the boundary itself. Although the sedimentary record across the K-Pg interval at Site 208 may not be completely continuous, it nevertheless captures a time interval that is close to the Chicxulub impact event

Re-discovery of a "living fossil" coccolithophore from the coastal waters of Japan and Croatia

The extant coccolithophore Tergestiella adriatica Kamptner, which had not been reported since its original description in 1940, was recently re-discovered in coastal-nearshore waters at Tomari, Tottori (Japan) and offshore Rovinj (Croatia). Morphological analysis shows that extant Tergestiella and the Mesozoic genus Cyclagelosphaera (Watznaueriaceae), thought to have been extinct since the early Eocene (~. 54. Ma), are virtually identical. Molecular phylogenetic study supports the inference that T. adriatica is a direct descendent of Cyclagelosphaera. It is therefore a remarkable example of a living fossil. Our documentation of patchy coastal distribution in living T. adriatica and records of rare occurrences of fossil Cyclagelosphaera in Oligocene-Miocene shallow water sediments. , from the New Jersey shelf, suggest that Tergestiella/. Cyclagelosphaera was restricted to nearshore environments during much of the Cenozoic. This restricted ecology explains the lack of fossil Tergestiella/. Cyclagelosphaera recorded in open ocean sediments deposited during the last 54. myr.Floristic study of coccolithophores in the coastal and offshore waters of Tomari over a six-year period, show that T. adriatica occurs synchronously with the unusual neritic species, Braarudosphaera bigelowii, in mid-June. The environmental factors that induce the co-occurrence of these two taxa are uncertain, and T. adriatica did not co-occur with B. bigelowii at any other sites

Late Maastrichtian carbon isotope stratigraphy and cyclostratigraphy of the Newfoundland Margin (Site U1403, IODP Expedition 342)

Earth’s climate during the Maastrichtian (latest Cretaceous) was punctuated by brief warming and cooling episodes, accompanied by perturbations of the global carbon cycle. Superimposed on a long-term cooling trend, the middle Maastrichtian is characterized by deep-sea warming and relatively high values of stable carbon-isotope ratios, followed by strong climatic variability towards the end of the Cretaceous. A lack of knowledge on the timing of climatic change inhibits our understanding of underlying causal mechanisms. We present an integrated stratigraphy from Integrated Ocean Drilling Program (IODP) Site U1403, providing an expanded deep ocean record from the North Atlantic (Expedition 342, Newfoundland Margin). Distinct sedimentary cyclicity suggests that orbital forcing played a major role in depositional processes, which is confirmed by statistical analyses of high resolution elemental data obtained by X-ray fluorescence (XRF) core scanning. Astronomical calibration reveals that the investigated interval encompasses seven 405-kyr cycles (Ma4051 to Ma4057) and spans the 2.8 Myr directly preceding the Cretaceous/Paleocene (K/Pg) boundary. A high-resolution carbon-isotope record from bulk carbonates allows us to identify global trends in the late Maastrichtian carbon cycle. Low-amplitude variations (up to 0.4‰) in carbon isotopes at Site U1403 match similar scale variability in records from Tethyan and Pacific open-ocean sites. Comparison between Site U1403 and the hemipelagic restricted basin of the Zumaia section (northern Spain), with its own well-established independent cyclostratigraphic framework, is more complex. Whereas the pre-K/Pg oscillations and the negative values of the Mid-Maastrichtian Event (MME) can be readily discerned in both the Zumaia and U1403 records, patterns diverge during a ~ 1 Myr period in the late Maastrichtian (67.8–66.8 Ma), with Site U1403 more reliably reflecting global carbon cycling. Our new carbon isotope record and cyclostratigraphy offer promise for Site U1403 to serve as a future reference section for high-resolution studies of late Maastrichtian paleoclimatic change

First Observation of the decay KL -> pi0 e e gamma

We report on the first observation of the decay KL -> pi0 ee gamma by the KTeV E799 experiment at Fermilab. Based upon a sample of 48 events with an estimated background of 3.6 +/- 1.1 events, we measure the KL -> pi0 ee gamma branching ratio to be (2.34 +/- 0.35 +/- 0.13)x10^{-8}. Our data agree with recent O(p^6) calculations in chiral perturbation theory that include contributions from vector meson exchange through the parameter a_V. A fit was made to the KL -> pi0 ee gamma data for a_V with the result -0.67 +/- 0.21 +/- 0.12, which is consistent with previous results from KTeV.Comment: Submitted to Physical Review Letters, 5 pages, 5 figure

Biotic and stable-isotope characterization of the Toarcian Ocean Anoxic Event through a carbonate–clastic sequence from Somerset, UK

This study focuses on a condensed sequence of alternating carbonate–clastic sediments of the Barrington Member, Beacon Limestone Formation (latest Pliensbachian to early Toarcian) from Somerset (SW England). Abundant ammonites confirm (apart from the absence of the Clevelandicum and Tenuicostatum ammonite subchronozones) the presence of Hawskerense Subchronozone to Fallaciosum–Bingmanni subchronozones. Well-preserved, sometimes diverse assemblages of ostracods, foraminifera, nannofossils and lowdiversity dinoflagellate assemblages support the chronostratigraphic framework. Stable-isotope analyses demonstrate the presence of a carbon isotope excursion, relating to the Toarcian Oceanic Anoxic Event, within the early Toarcian. Faunal, geochemical and sedimentological evidence suggest that deposition largely took place in a relatively deep-water (subwave base), mid-outer shelf environment under a well-mixed water column. However, reduced benthic diversity, the presence of weakly laminated sediments and changes in microplankton assemblage composition within the Toarcian Oceanic Anoxic Event indicates dysoxic, but probably never anoxic, bottom-water conditions during this event. The onset of the carbon isotope excursion coincides with extinction in the nannofossils and benthos, including the disappearance of the ostracod suborder Metacopina. Faunal evidence indicates connectivity with the Mediterranean region, not previously recorded for the UK during the early Toarcian