Products of chlorophyll diagenesis from DSDP Leg 57 Holes

Tetrapyrrole pigments isolated from sediments retrieved during Leg 57 include pheophytin-a, a myriad of chlorins, free-base deoxophylloerythroetioporphyrin (DPEP), as well as copper and nickel porphyrins. Their richness, both qualitatively and quantitatively, in chlorin tetrapyrroles affords a relatively complete study on the early diagenesis of chlorophyll. Our studies, coupled with those in the preceding chapter by Louda et al., point out the influence of pre- and postdepositional environments upon the mode of chlorophyll diagenesis. Formation of tetrapyrroles, collectively called "petroporphyrins," is seen to occur in only a limited set of environmental conditions (see Baker and Palmer, 1978). The more generalized route of chlorophyll diagenesis, at least in the ocean, results in removal of tetrapyrrole pigment, from the fossil record. Late diagenetic products, metalloporphyrins, are found to represent an extremely minor component of the tetrapyrrole assemblage in sediments studied from the Japan Trench. The products of chlorophyll diagenesis isolated from Japan Trench sediments allow expansion of previous diagenetic schemes (Baker and Palmer, 1978; Triebs, 1936) and indicate directions for future studies.

Physical oceanography from the Drake Passage and Bransfield Strait during Meteor cruise M56

This data publication is the electronic version of hydrographical and fluorometric data which were taken during the Antarctic cruise ANT I No. 56 of 'Meteor' from November 13th to December 18th 1980. The data were measured by means of the Optik Sonde (OS) of the SFB95. The data set contains the temperature and salinity profiles, the profiles of attenuation (extinction) coefficient at 670 nm wavelength and the fluorescence of chlorophyll expressed as chlorophyll a concentration values.

Radiosonde profiles and meteorological observations during Atlantic Expedition M2 in 1965 (IQSY) of RV "Meteor"

A radiosonde is described for measuring the upward and downward fluxes of visible light in the atmosphere. Photoresistors are used as sensors, the optical center of the spectral range beeing at 0.55 µ. The results of these flux-measurements obtained during the Atlantic Expedition 1965 with the research vessel "Meteor" are presented. The datas have been divided into three groups according to the amount of cloudiness. In group a) (small cloudiness) the extinction coefficient of the prevailing linear radiation is derived as a function of the height. Characteristics of airmasses of maritime or continental origin are shown. In group b) (cloud covered sky) microphysical quantities are determined from the radiative lapse rate in the clouds. The average radius of droplets is found to lie between 5.5 µm and 14.4 µm. The albedo of cloud surfaces varies between 25% and 54%, the transmission values are between 58% and 73%. One ascent through a Cirrus cloud of considerable vertical thickness is treated seperately. The observed distribution of extinction is compared with theoretical values in water clouds leading to the same order of magnitude. The relation between the albedo of the surface of the sea and the amount of cloudiness is discussed.