Measurement of nitric oxide in the stratosphere between 17·4 and 22·9 km

On 16 March 1973, the York U./U.S.U. chemiluminescent nitric oxide instrument was flown successfully from Hollomon Air Force Base, New Mexico, 32° 50·1′ N lat. The instrument was operated between 17:40 and 22:05UT. Most of the measurements were carried out during three ascent, float and descent cycles between 17·4 and 22·9 km. Within the uncertainty of the measurements no differences were seen among results obtained during ascent, float and descent mode, which indicated that there were no major sampling problems resulting from contamination of the atmosphere. The NO mixing ratio was found to be 0·1 ppb v/v with an accuracy of 60 per cent. No change was observed within this accuracy over the small altitude range investigated.     

Water quality in the Great Barrier Reef region: responses of mangrove, seagrass and macroalgal communities

Marine plants colonise several interconnected ecosystems in the Great Barrier Reef region including tidal wetlands, seagrass meadows and coral reefs. Water quality in some coastal areas is declining from human activities. Losses of mangrove and other tidal wetland communities are mostly the result of reclamation for coastal development of estuaries, e.g. for residential use, port infrastructure or marina development, and result in river bank destabilisation, deterioration of water clarity and loss of key coastal marine habitat. Coastal seagrass meadows are characterized by small ephemeral species. They are disturbed by increased turbidity after extreme flood events, but generally recover. There is no evidence of an overall seagrass decline or expansion. High nutrient and substrate availability and low grazing pressure on nearshore reefs have lead to changed benthic communities with high macroalgal abundance. Conservation and management of GBR macrophytes and their ecosystems is hampered by scarce ecological knowledge across macrophyte community types.     

Characteristics of air flow above and within soybean canopies

Air flow was observed above and within canopies of a number of kinds of soybeans. The Clark cultivar and two isolines of the Harosoy cultivar were studied in 1979 and 1980, respectively. Wind speed above the canopy was measured with cup anemometers. Heated thermistor anemometers were used to measure air flow within the canopy. Above-canopy air flow was characterized in terms of the zero-plane displacement (d), roughness parameter (z _o) and drag coefficient (C _d). d and z _o were dependent on canopy height but were independent of friction velocity in the range 0.55 to 0.75 m s^?1 · C _d for the various canopies ranged from 0.027 to 0.035. Greater C _d values were measured over an erectophile canopy than over a planophile canopy. C _d was not measurably affected by differences in leaf pubescence. Within-canopy wind profiles were measured at two locations: within and between rows. The wind profile was characterized by a region of great wind shear in the upper canopy and by a region of relatively weak wind shear in the middle canopy. Considerable spatial variability in wind speed was evident, however. This result has significant implications for canopy flow modeling efforts aimed at evaluating transport in the canopy. In the lower canopy, wind speed within a row increased with depth whereas wind speed between two rows decreased with depth. The wind speeds at the two locations tended to converge to a common value at a height near 0.10 m. The attenuation of within-canopy air flow was stronger in canopies with greater foliage density. Canopy flow attenuation seemed to decrease with increasing wind speed, suggesting that high winds distorted the shape of the canopy in such a manner that the penetration of wind into the canopy increased.     

Quantifying chemical changes in hydrothermally altered volcanic sequences — silica enrichment as a guide to the crandon massive sulfide deposit,Wisconsin, U.S.A.

A multi-element geochemical study of the wallrocks which host the large Precambrian Crandon deposit (≈ 70 million tons of zinc, copper ore) in Wisconsin, U.S.A. was carried out to identify pathfinder elements which significantly enlarge the size of the deposit as an exploration target. The Crandon deposit occurs in what appears to be a “normal”, subalkaline, intermediate to felsic volcanic sequence. The silica concentration of the wallrocks shows neither a systematic relationship to volcanic stratigraphy nor a distinctive pattern around ore.To determine if silica has been added to the host rocks, a regression analysis was performed on published data from 496 unaltered, subalkaline volcanic rocks from the Abitibi Subprovince of Canada, with silica as the dependent variable and the ratio of “immobile” elements Zr/TiO₂ as the independent variable. Based on the second degree regression curve and the associated standard error of estimate, predicted and residual silica values were calculated and plotted for the Crandon host rocks.The results show that massive sulfide ore was deposited in andesitic rocks with an original SiO₂ content of 52–62%, and that more than 7.4% SiO₂ was added to the rocks stratigraphically beneath the deposit and on strike with the deposit. Silica was added to the hanging wall rocks also, which confirms that hydrothermal activity at Crandon continued after cessation of massive sulfide ore deposition. In contrast to the pattern of silica enrichment at Crandon which significantly enlarges the size of the exploration target, two noneconomic prospects within ten miles of Crandon contain low to moderate levels of silica enrichment and corresponding low base metal values.Silica enrichment occurs in some systems unassociated with mineralization and is therefore not a specific signature of ore-forming processes. However, from the data presented on the Crandon deposit, if silica enrichment does exist in an exploration search area, the chances of finding a massive sulfide ore deposit are improved.     

The Cretaceous-Tertiary fireball layer,ejecta layer and coal seam: Platinum-group element content and mineralogy of size fractions

Abstract— Grain size separates of the Cretaceous-Tertiary (K-T) fireball layer at marine sites and the entire K-T boundary interval at nonmarine sites (fireball layer, ejecta layer, coal seam) were analysed for platinum-group elements (PGE: Ru, Ir, Ft, Pd, Rh) and Au using inductively coupled plasma mass-spectrometry. X-ray diffractometry and scanning electron microscopy were performed on each fraction to establish the mineralogy. It was determined that the most abundant minerals in the finest fraction were a smectite-group mineral at marine K-T sites and illite-smectite mixed layer clay at nonmarine K-T sites. Positive correlation of PGE content and mineralogy indicates that the PGE are presently associated with these clay minerals which were likely formed by alteration of a condensed mafic phase (e.g., olivine or pyroxene). The correlation of clay mineral abundance with PGE content is imperfect because not all of the clay minerals in the fireball layer are derived by alteration of the original condensed ejecta. In addition, undetected PGE host(s), present in trace amounts, are likely also present.     

GIS Investigation of the relationship of sex and season on the population distribution of common bottlenose dolphins (Tursiops truncatus) in Charleston,South Carolina

ABSTRACT

The Charleston Estuarine System Stock (CESS) of common bottlenose dolphins (Tursiops truncatus) has been the focus of population monitoring for the past 20 years. Photo-id studies have determined abundance and survival estimates for this population, which exhibits high site fidelity in this area. However, fine-scale distribution, utilization patterns, and the driving forces behind these patterns are lacking. Using historical photo-id data and a novel application of geographic information system (GIS) analysis, the present study identified core use areas within Charleston Harbor, as well as patterns specific to sexes and seasons. Photo-id data of 319 dolphins sighted 11 times or more during 2004–2009 were analyzed. Heat maps were developed to examine spatial distributions using kernel density estimates (KDE) and were compared between sexes and seasons. Multiple high-density core use areas were identified for this population, with the most noteworthy near the mouth of the harbor toward the Atlantic Ocean. Fine-scale distribution varied across sexes, as well as seasons. Some areas were identified as more specifically inhabited by one sex, while other areas overlapped between sexes. Females were more tightly concentrated within their distribution while males were more dispersed. Although population distribution varied across seasons, sex distributions remained.