Benthic community structure and water column characteristics at two sites in the Kermadec Islands Marine Reserve,New Zealand

The Kermadec Islands Marine Reserve (KIMR), which is located at 30°S, is New Zealand's largest marine reserve at 748 000 ha, and its biota is composed of a mix of warm temperate, subtropical, and tropical species. A depth‐stratified ecological survey was conducted of the abundance and percentage cover of macrobenthic species and of the water column at two sites (Meyer Island and West Chanter Island), 2km apart. Significant differences in benthic community structure and in water column turbidity and chlorophyll concentrations were observed between the two sites despite their proximity and physical similarity. Compared with other “snapshot” surveys of benthic community structure at sites within the KIMR there was a high degree of similarity among the species observed, but often a low degree of similarity in species abundance or percentage cover as a function of depth. We suggest that despite its isolation and the degree of difficulty of working at this location, a full‐scale ecological survey of the coastal marine biota of the KIMR is warranted to better understand New Zealand's subtropical marine biota and its affinities with other marine biotas of the South Pacific.     

Automated cleaning and uncertainty attribution of archival bathymetry based on a priori knowledge

Hydrographic offices hold large valuable historic bathymetric data sets, many of which were collected using older generation survey systems that contain little or no metadata and/or uncertainty estimates. These bathymetric data sets generally contain large outlier (errant) data points to clean, yet standard practice does not include rigorous automated procedures for systematic cleaning of these historical data sets and their subsequent conversion into reusable data formats. In this paper, we propose an automated method for this task. We utilize statistically diverse threshold tests, including a robust least trimmed squared method, to clean the data. We use LOESS weighted regression residuals together with a Student-t distribution to attribute uncertainty for each retained sounding; the resulting uncertainty values compare favorably with native estimates of uncertainty from co-located data sets which we use to estimate a point-wise goodness-of-fit measure. Storing a cleansed validated data set augmented with uncertainty in a re-usable format provides the details of this analysis for subsequent users. Our test results indicate that the method significantly improves the quality of the data set while concurrently providing confidence interval estimates and point-wise goodness-of-fit estimates as referenced to current hydrographic practices.     

Heavy metals in surface sediments of Waiwhetu Stream,Lower Hutt,New Zealand

Abstract

Surface sediment samples (60 μm‐2 mm, and < 60 μm fractions) from the Waiwhetu Stream, Lower Hutt City, New Zealand, were leached with dilute HCl to remove the mobile heavy‐metal fraction. Cd, Cr, Cu, Pb, Zn, Al, Fe, and Mn analyses of the leachates show that sediments of the upper reaches area of the stream are generally uncontaminated. In contrast, sediments in the lower reaches area are highly contaminated, despite clean‐up measures in the late 1970s. Lead and Zn are the most significantly enriched metals with concentrations over 1000 mg kg^?1 adjacent to some drains. In the polluted zone, metals originate from either upward remobilisation from underlying sediment (contaminated in the early 1960s and 70s) or more recent industrial spillages. Similar trends exhibited by Cd, Cu, Cr, Zn, Pb, and Al indicate that a proportion of the metal enrichment downstream probably results from a naturally higher clay content of sediments near the mouth of the stream. Fe and Mn show reverse trends to the other metals, indicating that a high proportion of these two metals occurs in substrate different to that of the other metals. The orange brick‐coloured sediments of the upper reaches of the stream indicate oxides upstream; the black sediments in the lower reaches indicate sulphides downstream.     

Short-range variations in the micromorphology of a palaeosol from Wivenhoe in southeast England

The pedogenic histories of four adjacent profiles of a polygenetic palaeosol developed on a Middle Pleistocene terrace of the proto-Thames from Wivenhoe in southeast England are reconstructed on the basis of superposition of key micromorphological features. Despite a considerable variation in macromorphology, partly resulting from large-scale periglacial features, three of the profiles have similar micromorphological records in that they retain evidence for two phases of clay illuviation separated by a period of periglacial disruption. This reconstruction, however, seems to be incomplete because the fourth profile contains micromorphological evidence for a further illuviation–disruption cycle. The extent of this variation suggests that soil micromorphology should be used only with care to reconstruct pedogenic or pedosedimentary histories of complex polygenetic palaeosols, or to compare such palaeosols on different surfaces of chronosequences spanning periods of major climatic change. The variable and possibly limited resolution of micromorphology, together with the current uncertainty over the exact environmental signifiance of illuvial clay features, means that inferred pedogenic phases should be correlated with specific climatic stages only with considerable caution. © 1998 John Wiley & Sons, Ltd.     

Modeling an irrigation ditch opens up the world. Hydrology and hydraulics of an ancient irrigation system in Peru

Ancient Peruvian irrigation systems have been studied extensively, but much remains unknown about technical and hydrological aspects of these irrigation systems. The Pampa de Chaparrí irrigation system in Peru is used as an example to show how modeling approaches for hydrological and hydraulic features of irrigation can yield results to improve our understanding of irrigation in the area. Analysis focuses on water availability compared demand, the way available water may have been applied to crops and whether the water needed could be delivered through the canal system. Results suggest that on the Pampa some 2500 hectares may have been cultivated within certain security limits for acceptable yields. The rhythm with which the irrigation requirement was applied to crops most likely influenced yields and thus food security. Furthermore, the influence of groundwater on crop growth may have been considerable. The hydraulic behavior of the irrigation system suggests that it should not be taken for granted that theoretically required water flows could actually be diverted and/or distributed to water users. The many questions coming out of the results define important items for a joint research agenda of archeologists and irrigation scientists.     

Geothermal control on flow patterns in the Last Glacial Maximum ice sheet of Iceland

Because it is located both on the Mid‐Atlantic Ridge and on a mantle plume, Iceland is a region of intense tectonics and volcanism. During the last glaciation, the island was covered by an ice sheet approximately 1000 m thick. A reconstruction of the ice flow lines, based on glacial directional features, shows that the ice sheet was partly drained through fast‐flowing streams. Fast flow of the ice streams has been recorded in megascale lineations and flutes visible on the currently deglaciated bedrock, and is confirmed by simple mass balance considerations. Locations of the major drainage routes correlate with locations of geothermal anomalies, suggesting that ice stream activity was favoured by lubrication of the bed by meltwater produced in regions of high geothermal heat flux. Similar control of ice flow by geothermal activity is expected in ice sheets currently covering tectonically and volcanically active area such as the West Antarctic ice sheet. Copyright © 2000 John Wiley & Sons, Ltd.     

Towards a critical analysis of fictive geographies

Summary The recent 'culture turn' in geography has generated a good deal of interest in the structure of scientific knowledge and modes of writing, but there has less attention to the construction of other forms of knowledge and writing. While humanistic and regional geographers have referred to literature on the whole without comment on genre, mode of production or range of consumption, more recent critical geographers have regarded literature as a material artefact which fulfils a role designated by its position in various social and economic processes. This paper critiques both positions as offering a limited vision of the relationship between geography and literature and attempts to offer an engagement with literary fiction which analyses the content and form of the text, but also leaves room for its distinctive voice.     

High-Reflectivity Coatings for a Vacuum Ultraviolet Spectropolarimeter

Precise polarization measurements in the vacuum ultraviolet (VUV) region are expected to be a new tool for inferring the magnetic fields in the upper atmosphere of the Sun. High-reflectivity coatings are key elements to achieving high-throughput optics for precise polarization measurements. We fabricated three types of high-reflectivity coatings for a solar spectropolarimeter in the hydrogen Lyman-\(\upalpha \) (Ly\(\upalpha \); 121.567 nm) region and evaluated their performance. The first high-reflectivity mirror coating offers a reflectivity of more than 80 % in Ly\(\upalpha \) optics. The second is a reflective narrow-band filter coating that has a peak reflectivity of 57 % in Ly\(\upalpha \), whereas its reflectivity in the visible light range is lower than 1/10 of the peak reflectivity (\(\sim 5~\%\) on average). This coating can be used to easily realize a visible light rejection system, which is indispensable for a solar telescope, while maintaining high throughput in the Ly\(\upalpha \) line. The third is a high-efficiency reflective polarizing coating that almost exclusively reflects an s-polarized beam at its Brewster angle of 68° with a reflectivity of 55 %. This coating achieves both high polarizing power and high throughput. These coatings contributed to the high-throughput solar VUV spectropolarimeter called the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP), which was launched on 3 September, 2015.     

The Canada-Newfoundland Atlantic Accord Implementation Act: Transparency of the environmental management of the offshore oil and gas industry

This paper considers the overall outcome of a “public environmental audit” of the government management of the oil and gas offshore industry in eastern Canada. Five requests for data sets were placed using the Access to Information Act; all five requests were denied by the Canada-Newfoundland Labrador Offshore Petroleum Board. This lack of access to environmental monitoring data significantly hinders the ability of independent scientific inquiry and/or public involvement in the environmental assessment process.