Marble Point Research Articles

Visual recovery of desert pavement surfaces following impacts from vehicle and foot traffic in the Ross Sea region of Antarctica

AbstractSites of past human activity were investigated to assess the visual recovery of the desert pavement following impacts from human trampling and vehicle traffic. Visually disturbed and nearby control sites were assessed using comparative photographic records, a field-based Visual Site Assessment, and Desert Pavement Recovery Assessment. Sites included: vehicle and walking tracks at Marble Point and Taylor Valley; a campsite, experimental treading trial site, and vehicle tracks in Wright Valley; and vehicle and walking tracks at Cape Roberts. The time since last disturbance ranged from three months to over 50 years. This investigation also attempted to determine what has the greatest lasting visual impact on soil surfaces in the Ross Sea region: dispersed trafficking or track formation? Walking tracks remained visible in the landscape (due to larger clasts concentrating along track margins) long after the desert pavement surface had recovered. However, randomly dispersed footprints were undetectable within five years. For many sites, allowing widespread trampling will give lower medium-term visible impact than concentrating traffic flow by track formation. For steep slopes and sites where repeated visits occur, use of a single track is recommended. Some 1950s vehicle tracks remain visible in the Antarctic landscape, but where visually obvious impacts were remediated, evidence of former occupation was almost undetectable.

A method for assessing the physical recovery of Antarctic desert pavements following human-induced disturbances: A case study in the Ross Sea region of Antarctica

With increasing visitor numbers an understanding of the impacts of human activities in Antarctic terrestrial environments has become important. The objective of this study was to develop a means for assessing recovery of the ground surface desert pavement following physical disturbance. A set of 11 criteria were identified to assess desert pavement recovery. Assessed criteria were: embeddedness of surface clasts; impressions of removed clasts; degree of clast surface weathering; % overturned clasts; salt on underside of clasts; development of salt coatings; armouring per m2; colour contrast; evidence of subsidence/melt out; accumulation of salt on cut surfaces; and evidence of patterned ground development. Recovery criteria were assigned a severity/extent rating on a scale from zero to four, zero being highly disturbed, and four being undisturbed. A relative % recovery for each criteria was calculated for each site by comparison with a nearby undisturbed control area, and an overall Mean Recovery Index (MRI) was assigned to each pavement surface.To test the method, 54 sites in the Ross Sea region of Antarctica were investigated including areas disturbed by: bulldozer scraping for road-fill, contouring for infrastructure, geotechnical investigations, and experimental treading trial sites. Disturbances had occurred at timescales ranging from one week to 50 years prior to assessment. The extent of desert pavement recovery at the sites investigated in this study was higher than anticipated. Fifty of the 54 sites investigated were in an intermediate, or higher, stage of desert pavement recovery, 30 sites were in an advanced stage of recovery, and four sites were indistinguishable from adjacent control sites (MRI = 100%). It was found that active surfaces, such as the gravel beach deposits at the Greenpeace World Park Base site at Cape Evans, the aeolian sand deposits at Bull Pass, and the alluvial fan deposits of the Loop Moraine field campsite, recovered relatively quickly, whereas less active sites, such as the bulldozed tracks at Marble Point, and Williams Field to McMurdo Station pipeline site on Ross Island, showed only intermediate recovery 20–30 years after disturbance. The slabby grano-diorite surface material at the former Vanda Station site, meant that the impacts that had occurred were hard to detect following decommissioning of the station and site remediation. Desert pavements disturbed by randomly dispersed footprints, temporary field campsites at the Loop Moraine and VXE6 Pond in the Wright Valley, recovered to be undetectable (MRI = 100%) within five years, whereas track formation from repeated trampling, particularly the concentration of larger clasts along the margin of a confined track, persisted for over 15 years (MRI = 82%). The recovery assessment method developed in this study has environmental management applications and potential to advance our ability to predict the recovery of desert pavement following human impacts from activities in Antarctica.

Hexadecane mineralization activity in hydrocarbon-contaminated soils of Ross Sea region Antarctica may require nutrients and inoculation

Hydrocarbon spills on Antarctic soils occur mainly near settlements where fuel is stored and aircraft and vehicles are refuelled. To investigate those factors that may preclude hexadecane mineralization activity in long-term hydrocarbon-contaminated soils from the Ross Sea Region, samples were collected from Scott Base, the site of former bases (Cape Evans, Marble Point, Vanda Station), and two oil spill sites in the Wright Valley (Bull Pass and Loop Moraine). The soils had low levels of nitrogen (<0.1% total N) and a high C/N ratio (>24) reflecting hydrocarbon contamination. Following soil water adjustment to 10% (v/w), the influence of nutrient addition (250 mg/kg N added as monoammonium phosphate) and inoculation (spiking with Antarctic soil containing high numbers of hydrocarbon degraders) as required on hexadecane mineralization activity was determined. Hexadecane mineralization activity occurred in contaminated soils from Marble Point, Cape Evans and one sample from Vanda Station without nutrient addition. In contrast soils from Scott Base, Cape Evans, another sample from Vanda Station and Loop Moraine required nutrients, whereas Bull Pass soil required inoculation and nutrients before hexadecane mineralization proceeded. Hydrocarbon degrader numbers were highest in coastal soils from Scott Base and Marble Point (107 per gram) and less prevalent in inland soils from Wright Valley (<105 per gram). The bacterial community structure of the soils differed between sites, but soils from the same sites tended to cluster together more closely, except for those from Vanda Station. Addition of nutrients did not cause large shifts in the soil bacterial communities. Results from this study indicate that hydrocarbon degradation may occur at some sites in summer when water is available. Long-term hydrocarbon-contaminated Antarctic soils may provide a valuable resource of hydrocarbon-degrading bacteria that can serve as inocula for more recent oil spills on land.

Permafrost thermal regime from two 30‐m deep boreholes in southern victoria land, antarctica

ABSTRACTTwo 30‐m deep permafrost temperature‐monitoring boreholes were installed in bedrock, one at Marble Point and one in the Wright Valley, in the Ross Sea region of Antarctica. A soil climate‐monitoring station in till is located near each borehole. The ground surface temperature (GST) was highly correlated with the air temperature at both sites in 2008. Thermal offsets were small (&lt; 1 °C) in the till and negligible in the boreholes. The active layer was thicker in the boreholes than in the till, presumably because of the higher thermal diffusivity of the rock. The measured depth of zero annual temperature amplitude was around 27 m at Wright Valley and 25 m at Marble Point. Permafrost thickness was estimated at about 680 m at Wright Valley and 490 m at Marble Point. The GST history, reconstructed using an inversion procedure, suggests a slight cooling from 1998 to 2003 followed by a slight warming to 2008. Longer temperature records or deeper boreholes would be required to establish if long‐term climate change has occurred. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Characterization of active layer water contents in the McMurdo Sound region, Antarctica

AbstractThe liquid soil water contents in the seasonally thawed layer (active layer) were characterized from seven soil climate monitoring sites - four coastal sites from south to north (Minna Bluff, Scott Base, Marble Point and Granite Harbour), and inland sites from low to high altitude (Wright Valley, Victoria Valley and Mount Fleming). Mean water contents ranged from 0.013 m3 m-3 near the surface at Victoria Valley to 0.33 m3 m-3 near the ice-cemented layer at Granite Harbour. The coastal sites have greater soil water contents than the McMurdo Dry Valley and Mount Fleming sites, and moisture contents increase with depth in the active layer. The Wright Valley site receives very little infiltration from snowmelt, with none in most years. All other sites, except Mount Fleming, received between one and four wetting events per summer, and infiltrated water moved to greater depths (≈ 10–25 cm). The Scott Base and Granite Harbour sites are on sloping ground and receive a subsurface flow of water along the ice-cemented permafrost. Our findings indicate that water contents are low with very little recharge, are greatly influenced by the local microclimate and topography, and show no significant increasing or decreasing trend over 10 years of monitoring.

Temporal and spatial variation in active layer depth in the McMurdo Sound Region, Antarctica

A soil climate monitoring network, consisting of seven automated weather stations, was established between 1999 and 2003, ranging from Minna Bluff to Granite Harbour and from near sea level to about 1700 m on the edge of the polar plateau. Active layer depth was calculated for each site for eight successive summers from 1999/2000 to 2006/2007. The active layer depth varied from year to year and was deepest in the warm summer of 2001-02 at all recording sites. No trends of overall increase or decrease in active layer depth were evident across the up-to-eight years of data investigated. Average active layer depth decreased with increasing latitude from Granite Harbour (778S, active layer depth of . 90 cm) to Minna Bluff (78.58S, active layer depth of 22 ± 0.4 cm), and decreased with increasing altitude from Marble Point (50 m altitude, active layer depth of 49 ± 9 cm) through to Mount Fleming (1700 m altitude, active layer depth of 6 ± 2 cm). When all data from the sites were grouped together and used to predict active layer depth the mean summer air temperature, mean winter air temperature, total summer solar radiation and mean summer wind speed explained 73% of the variation (R 2 5 0.73). Received 9 December 2008, accepted 8 June 2009

Zeolites in Antarctic soils: Examples from Coombs Hills and Marble Point

The distribution of zeolites in rocks and soils of the McMurdo Sound region is reviewed and two new occurrences are described, One of these is in the Coombs Hills where mordenite derived from hyaloclastic rocks is found in soils formed from till. The other is of phillipsite, found at Marble Point in a bedded formation which appears to have been formed by ash falling into an ice-dammed lake. It is likely that authigenic zeolites may be more widely distributed in Antarctica soils than is currently recognised.

Relation between soil classification and bacterial diversity in soils of the Ross Sea region, Antarctica

Soils of the Ross Sea region of Antarctica are among the least diverse ecosystems on earth. Few plants and animals have colonised these soils, but bacteria are distributed throughout. We compared the bacterial communities of soil samples from 5 locations in the Ross Sea region, representing different soil taxonomic groups, using culture-independent methods. Four mineral soils and one ornithogenic soil were analysed. Organic C, Total N, and moisture of the mineral soils were low, total P and EC were variable. In contrast, the water content, organic C, and Total N and P, and EC of the ornithogenic soil were 10–100 fold higher than the mineral soils. Soil pH was alkaline. One thousand and fourteen clones were screened by restriction fragment length polymorphisms. While the majority of the ribotypes were rare, some were dominant and occurred ≥ 3 times in the respective clone libraries. The dominant ribotypes were sequenced and shown to be phylogenetically affiliated with the phyla Acidobacteria, Actinobacteria, Bacteroidetes, Proteobacteria, Deinococcus-Thermus, Firmicutes, Cyanobacteria and Candidate TM7. The closest relatives of the clones retrieved from the mineral soils were uncultured environmental clones or bacterial isolates not assigned to recognised genera. In contrast, the clones from the ornithogenic soil were most closely related to the endospore-formers; Oceanobacillus profundus, Clostridium acidiurici and Sporosarcina aquimarina. We found no convincing evidence that the Haplorthels from Scott Base, Marble Point, and Cape Hallett, have bacterial communities structured fundamentally different from those of Anhyorthels from Bull Pass and Vanda. Nonetheless the composition of the communities did vary substantially and were readily discriminated by multivariate statistics on the basis of soil properties.

Dominant bacteria in soils of Marble Point and Wright Valley, Victoria Land, Antarctica

A combination of culture-independent and culturing methods was used to assess the diversity of soil bacterial communities from four locations along 77 °S in Victoria Land, Antarctica. Soil samples were from the coast at Marble Point, in the Wright Valley from Bull Pass and near Lake Vanda, and from Mt. Fleming near the polar plateau. Total carbon and nitrogen, and water content of the soils were low, whereas total P was very high. The pH of the soils varied from extremely alkaline to slightly acid and electrical conductivity was medium to high on the coast and very high in inland soils from Bull Pass and Mt. Fleming. The average monthly air temperature was similar (−18 °C to −24 °C) at all the sites; however, in summer surface soil temperatures were >0 °C at Marble Point and in the Wright Valley for a total of 1100 and 1700 h, respectively. Marble Point soil had the most potential to support bacterial growth and activity with a mean total of 310 h per year when surface soils had a liquid volumetric soil moisture content >5%. Highest counts of culturable heterotrophs occurred in soil from Marble Point, whereas Mt. Fleming soil contained few organisms and had no liquid soil moisture recorded. Seven hundred and twenty-eight clones and 71 bacterial isolates were screened by restriction fragment length polymorphisms, and representatives of those dominant ribotypes that occurred more than 3 times were sequenced. The dominant ribotypes grouped within the bacterial divisions Bacteroidetes, Actinobacteria, Proteobacteria, Thermus-Deinococcus, Acidobacteria, Firmicutes and Cyanobacteria. The closest relatives of the amplicon library clones or cultured bacteria include the genera Hymenobacter, Gillisia, Arthrobacter, Rubrobacter, Friedmanniella, Deinococcus and Leptolyngbya. Many of the clones and bacteria were most similar to others from Antarctic sources, in particular a cyanobacterium-dominated cryptoendolithic community in Beacon sandstone. Some ribotypes were more prevalent in drier soils of the Wright Valley, including relatives of Deinococcus, Rubrobacter and clone FBP460 from Beacon sandstone. Bacterial communities from Marble Point soils were more diverse than those of the Wright Valley. Very few bacteria were isolated from Mt. Fleming soil.

Effects of hydrocarbon spills on the temperature and moisture regimes of Cryosols in the Ross Sea region

Hydrocarbon spills have occurred on Antarctic soils where fuel oils are utilized, moved or stored. We investigated the effects of hydrocarbon spills on soil temperature and moisture regimes by comparing the properties of existing oil contaminated sites with those of nearby, uncontaminated, control sites at Scott Base, the old Marble Point camp, and Bull Pass in the Wright Valley. Hydrocarbon levels were elevated in fuel-contaminated samples. Climate stations were installed at all three locations in both contaminated and control sites. In summer at Scott Base and Marble Point the mean weekly maximum near surface (2 cm and 5 cm depth) soil temperatures were warmer (P&lt;0.05), sometimes by more than 10°C, at the contaminated site than the control sites. At Bull Pass there were no statistically significant differences in near-surface soil temperatures between contaminated and control soils. At the Scott Base and Marble Point sites soil albedo was lower, and hydrophobicity was higher, in the contaminated soils than the controls. The higher temperatures at the Scott Base and Marble Point hydrocarbon contaminated sites are attributed to the decreased surface albedo due to soil surface darkening by hydrocarbons. There were no noteworthy differences in moisture retention between contaminated and control sites.

Expanded distributional records of Collembola and Acari in southern Victoria Land, Antarctica

Summary We provide new distributional records for the Collembola and Acari from south Victoria Land in the Ross Dependency, Antarctica, including the first extensive survey of Taylor Valley. We also describe the design of a modified device for the rapid sampling of Antarctic terrestrial arthropods. Sampling was carried out during the austral summers from 1998 to 2001. In several instances we found Gomphiocephalus hodgsoni, Neocryptopygus nivicolus and Stereotydeus mollis at sites where they were not reported in comprehensive surveys made some 40 years ago, which may imply recent range expansion (eg: local dispersal). By contrast, at McMurdo Station and at the former North Base (Marble Point) the distribution of G. hodgsoni and S. molliswas restricted, relative to previous records. We conclude that these latter changes may be the direct result of human activities.

A new microfungal isolate, Embellisia sp., associated with the Antarctic moss Bryum argenteum

A microfungal isolate of Embellisia sp. (Simmons), assigned Embellisia sp2, not previously described from the Antarctic, has been identified by morphological means and internal transcribed spacer (ITS) region sequencing. Embellisia sp2 was shown to be associated with the bryophyte Bryum argenteum, collected from Marble Point in Southern Victoria Land, Antarctica, and grew only in samples plated from crushed moss tissue and surface-sterilized leafy stems. Two other types of microfungi, Penicillium sp. and Trichoderma sp., were cultivated from a surface rinse of the moss.

Heavy metal content of meltwaters from the Ross Dependency, Antarctica

Twenty‐eight meltwater samples were collected from Scott Base, Cape Evans, Cape Royds, Marble Point, Vanda Station, and along the length of the Onyx River, in the McMurdo Sound area of Antarctica during the summers of 1992/93 and 1993/94. Samples were analysed for major components, and for heavy metals at ultra‐trace levels. The sample sites included biologically active ponds, glacier melt water, lake water, roadside drains, and rivers. Sample salinities varied widely, but heavy‐metal concentrations were uniformly low except where significant human impacts would have been expected. Concentrations of silver, mercury, lead, copper, cadmium, chromium, nickel, and zinc were higher at Scott Base than in the other areas and were dominantly associated with coarse particulates. Natural sources of metals may be local lithology, but chemical and mechanical processes within the soils and solutions affect the distributions of different metals.

Heavy metal contamination in some soils of the McMurdo Sound region, Antarctica

Soil samples from eight sites at Marble Point and Pram Point, McMurdo Sound region, contaminated by human activities were examined for heavy metal content, using sequential extraction methods. The redistribution of lead, zinc and copper arising from point sources of these metals was demonstrated. The levels found are not considered to represent serious pollution but do indicate that human activities can change the chemistry of the Antarctic environment in localized areas.

The effect of human activities on moisture content of soils and underlying permafrost from the McMurdo Sound region, Antarctica

Soils and the underlying permafrost from undisturbed sites and sites that had been disturbed by construction activities at Marble Point and Pram Point in the McMurdo Sound region were sampled from excavated pits and drill cores. Gravimetric moisture (ice) contents and particle size distribution were determined. Volumetric moisture contents were calculated from these results. At undisturbed sites soil moisture contents within the active layer (to c. 60 cm depth) were low and ranged from 0.5% by weight at the soil surface to 10% above the permafrost. The permafrost was generally completely saturated with ice, but sometimes contained considerable excess ice, with ice contents rising as high as 80% by volume. At disturbed sites, soil moisture contents within the active layer were similar to those of the undisturbed sites (generally &lt;10% by weight) but within the permafrost, moisture contents were lower and less variable than in the undisturbed sites, rarely exceeding 20% by weight. The release of considerable quantities of water from the permafrost as a result of land disturbance during construction activities caused stream flows, soil shrinkage, land slumping and salinisation, resulting in significant permanent environmental damage. At Marble Point there has been no significant re-establishment of icy permafrost in the disturbed soils in the 30 years since land disturbance occurred.

A simple visual technique for estimating the impact of fieldwork on the terrestrial environment in ice-free areas of Antarctica

ABSTRACTA set of simple criteria for visual assessment of the effects of low-intensity fieldwork in ice-free areas of Antarctica was developed. These criteria were tested by using them to examine the impact of soil science investigations, both immediately and some time after disturbance, at Marble Point and at Cape Evans, on the shores of McMurdo Sound, Antarctica. The use of these criteria showed that for some types of impacts there had been a marked recovery of the surface with time, ranging from 22 months to 30 years. This was apparently due to repeated freeze and thaw of the soil surface and, to a lesser extent, to the influence of wind, which had partly or completely obliterated some of the earlier disturbances. More durable features remained, while deeper surface impressions, such as old soil inspection pits and vehicle tracks, showed little recovery after more than 30 years. Some biological colonisation of areas disturbed 30 years previously was occurring.

Dry Valley Drilling Project

As a consequence of recent meetings held in New Zealand and Antarctica by science and administrative coordinators from Japan. New Zealand, and the United States, a three‐year drilling project (1972–1975) in the Dry Valleys region of Antarctica has been proposed and approved. The project (Dry Valley Drilling Project) is to be funded, in part, by the National Science Foundation and by antarctic research groups from Japan and New Zealand, using McMurdo station as a base of operations. The project, in addition to the advantages of having international support, will be multidisciplinary and will include ten boreholes drilled to a maximum depth of 600 meters. Recommended drill sites include: Ross Island into McMurdo volcanics; McMurdo Sound into interbedded marine, glacial, and volcanic deposits; Marble Point metamorphics; Lake Vida in Victoria Valley; Don Juan Pond in Wright Valley; Lake Vanda in Wright Valley; mouth of Taylor Valley near the coast; Lake Fryxell in Taylor Valley; Lake Bonney in Taylor Valley; and Walcott glacier area It is hoped that collection of continuous core from these site locations will enable scientists to develop a better working knowledge of the physical and biological history of the antarctic continent, from Precambrian time to the present.

Cretaceous Greywackes

The age of the North Auckland greywackes has long been a matter of conjecture. The discovery of Aucelltna euglypha at Motukahakaha Bay in 1948 showed some to be of Motuan age. In 1950 fusulines and corals were discovered at Marble Point near Whangaroa Harbour, and at Wairoa Bay and Waikare Inlet, both in the Bay of Islands, which showed others were of Permian age.

Coastal Geomorphology, McMurdo Sound, Antarctica

Abstract Well-developed elevated beaches. deltaic deposits, marine-boulder pavements and wave-washed bedrock surfaces are found from Cape Bernacchi north to Granite Harbour. The highest measured marine feature, an elevated beach at Dunlop Island, is 20 m (67 ft) above sea-level. The highest beaches at Marble Point and Cape Roberts, about 48 km (30 miles) apart, are about 20 m (66 ft) above sea-level. The marine limit between these two points is, therefore, essentially horizontal. The highest beach at Cape Bernacchi. approximately 4.8 km (3 miles) south of Marble Point, is about 12 m (40 ft) above sea-level, Well-developed elevated beaches disappear about 3.2 km (2 miles) south of Cape Bernacchi and are not found between this point and Koettlitz Glacier. These beaches post-date the youngest glaciation recognized in the lower Wright Valley. A 14C analysis of an elephant seal buried in a 13 m (44 ft) beach at Marble Point indicates that this beach is 4450 ± 150 years old. As sea-level at this time was approximately 3 m (10 ft) lower than at present. the Marble Point area has risen isostatically about 16 m (54 ft) during the last 4450 ± 150 years. Pitted beaches, beaches deposited on ice, a buried elephant seal and gravel ridges deposited by ice indicate that all of the beaches were formed in a climate like that now found in the area.

Coastal Geomorphology, McMurdo Sound, Antarctica

AbstractWell-developed elevated beaches. deltaic deposits, marine-boulder pavements and wave-washed bedrock surfaces are found from Cape Bernacchi north to Granite Harbour. The highest measured marine feature, an elevated beach at Dunlop Island, is 20 m (67 ft) above sea-level. The highest beaches at Marble Point and Cape Roberts, about 48 km (30 miles) apart, are about 20 m (66 ft) above sea-level. The marine limit between these two points is, therefore, essentially horizontal. The highest beach at Cape Bernacchi. approximately 4.8 km (3 miles) south of Marble Point, is about 12 m (40 ft) above sea-level, Well-developed elevated beaches disappear about 3.2 km (2 miles) south of Cape Bernacchi and are not found between this point and Koettlitz Glacier.These beaches post-date the youngest glaciation recognized in the lower Wright Valley. A 14C analysis of an elephant seal buried in a 13 m (44 ft) beach at Marble Point indicates that this beach is 4450 ± 150 years old. As sea-level at this time was approximately 3 m (10 ft) lower than at present. the Marble Point area has risen isostatically about 16 m (54 ft) during the last 4450 ± 150 years.Pitted beaches, beaches deposited on ice, a buried elephant seal and gravel ridges deposited by ice indicate that all of the beaches were formed in a climate like that now found in the area.