Multidecadal variations in the early Holocene outflow of Red Sea Water into the Arabian Sea

We present Holocene stable oxygen isotope data from the deep Arabian Sea off Somalia at a decadal time resolution as a proxy for the history of intermediate/upper deep water. These data show an overall δ18O reduction by 0.5‰ between 10 and ~6.5 kyr B.P. superimposed upon short-term δ18O variations at a decadal-centennial timescale. The amplitude of the decadal variations is 0.3‰ prior, and up to 0.6‰ subsequent, to ~8.1 kyr B.P. We conclude from modeling experiments that the short-term δ18O variations between 10 and ~6.5 kyr B.P. most likely document changes in the evaporation-precipitation balance in the central Red Sea. Changes in water temperature and salinity cause the outflowing Red Sea Water to settle roughly 800 m deeper than today

Estrogen receptors and biologic response in rat parathyroid tissue and C cells.

The expression of the PTH and calcitonin genes is dramatically decreased by 1,25(OH)2D3 in vivo, and the PTH gene expression is increased by hypocalcemia. We have now studied the effect of estrogens on the expression of these genes in vivo. 17 beta-Estradiol, given to ovariectomized rats, led to a fourfold increase in PTH mRNA and calcitonin mRNA levels. These effects occurred 24 h after single injections of 37-145 nmol estradiol, or after constant infusions of 12 pmol/d for 1 or 2 wk, where there was no effect on serum calcium levels. The estrogen receptor mRNA was demonstrated in the thyroparathyroid tissue by polymerase chain reaction. The estrogen binding was localized to the parathyroid and C cells by immunohistochemistry. Uterus weight was increased by repeated larger doses (73 nmol/d x 7) of estradiol, but not by the small doses (12 pmol/d for 1 or 2 wk) which were effective on the PTH and calcitonin genes, suggesting a sensitive endocrine effect. These results confirm that the parathyroid and C cells are target organs for estrogen, leading to an increased expression of PTH and calcitonin, which by their combined anabolic effect on bone would help prevent osteoporosis

The Conch of Limacina and Peraclis (Pteropoda) and a Model for the Evolution of Planktonic Gastropods

Pteropod shell morphologies can be explained by neotenic extension of larval features observed in benthic forms, such as the sinistral coiling of Architectonacea and the ornamentation patterns of Tonnacea, into the adult shell of permanently planktonic living snails. Presented models suggest derivation of pteropods from primitive prosobranch mesogastropods of the Late Paleozoic, rather than from opistobranchs

Late Holocene pteropod distribution across the base of the south-eastern Mediterranean margin: the importance of the <i>&gt;</i>&thinsp;63&thinsp;µm fraction

Euthecosomata pteropods were analysed in core sediments collected in the framework of the 2016 EUROFLEETS2 SEMSEEP cruise, offshore of Israel, in the eastern Mediterranean Sea. The investigated cores were retrieved in a deep-sea coral area at 690 m depth, an actively methane-seeping pockmark area at 1038 m depth, and a deep-sea channel area at 1310 m water depth. We identified and documented the pteropod species belonging to the families Heliconoididae, Limacinidae, Creseidae, Cavoliniidae, Cliidae, and Hyalocylidae and to some heteropods. Our study highlights the importance of investigating pteropods in the size fractions &gt; 63 µm instead of the &gt; 125 µm only. In particular, neglecting the small size fraction may result in a remarkable (up to 50 %–60 %) underestimation of the relative abundance of the epipelagic species Creseis acicula and Creseis conica and the mesopelagic species Heliconoides inflatus. This may significantly affect palaeoenvironmental reconstructions. The observed presence of tropical species supports the suggestion that the eastern Mediterranean is a refugium for these species. This study provides a basic benchmark for the late Holocene evolution of pteropod and heteropod distribution over 5800–5300 cal BP across the base of the south-eastern Levantine margin.</p