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Christian Fritsen

Christian Fritsen

PhD, U So. California

About

109
Publications
17,920
Reads
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3,554
Citations
Additional affiliations
July 2015 - present
National Science Foundation
Position
  • Program Director Antarctic Organisms and Ecosystems
January 1999 - present
University of Nevada, Reno
Position
  • Professor (Associate)
July 1998 - present
Desert Research Institute
Position
  • Professor
Education
January 1990 - May 1996
University of Southern California
Field of study
  • Marine Sciences

Publications

Publications (109)
Article
Lake Vida, located in a closed basin in the McMurdo Dry Valleys, East Antarctica, permanently encapsulates an interstitial anoxic, aphotic, cold (−13 °C), brine ecosystem within 27+ m of ice. Metabolically active, but cold-limited, slow-growing bacteria were detected in the brine. Lake Vida brine is derived from the evaporation of a body of water t...
Article
Full-text available
Temporal changes in the concentration profiles of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), and dimethylsulfoxide (DMSO) were measured in pack ice from the Bellingshausen Sea (Antarctica) during the winter-spring transition of 2007. Two sites with contrasting snow and ice thicknesses were sampled, with high concentrations of DMS, DM...
Article
The cold (−13.4°C), cryoencapsulated, anoxic, interstitial brine of the >27 m thick ice of Lake Vida (Victoria Valley, Antarctica) contains 49 µg · L−1 of perchlorate and 11 µg · L−1 of chlorate. Lake Vida brine (LVBr) may provide an analog for potential oxychlorine-rich subsurface brine on Mars. LVBr volatiles were analyzed by solid-phase microext...
Article
Full-text available
Lake Vida, located in Victoria Valley, is one of the largest lakes in the McMurdo dry valleys and is known to contain hypersaline liquid brine sealed below 16 m of freshwater ice. For the first time, Lake Vida was drilled to a depth of 27 m. Below 21 m the ice is marked by well-sorted sand layers up to 20 cm thick within a matrix of salty ice. From...
Article
Full-text available
Recently, technologies have been developed that offer the possibility of using algal biomass as feedstocks to energy producing systems - in addition to oil-derived fuels (Bird et al., 2011, 2012). Growing native mixed microalgal consortia for biomass in association with geothermal resources has the potential to mitigate negative impacts of seasonal...
Article
Full-text available
The freshwater stalked diatom Didymosphenia geminata can alter benthic community structure. However, the numbers of D. geminata that must be present to do this is not clear. Is it possible that benthic communities in streams with D. geminata are not altered? A comparison of benthic communities in two similar, adjacent streams (one with and one with...
Article
Full-text available
Lake Vida, located in Victoria Valley, is one of the largest lakes in the McMurdo Dry Valleys. Unlike other lakes in the region, the surface ice extends at least 27 m, which has created an extreme and unique habitat by isolating a liquid-brine with salinity of 195 g L−1. Below 21 m, the ice is marked by well-sorted sand layers up to 20 cm thick, wi...
Article
Full-text available
The anoxic and freezing brine that permeates Lake Vida's perennial ice below 16 m contains an abundance of very small (≤0.2-μm) particles mixed with a less abundant population of microbial cells ranging from >0.2 to 1.5 μm in length. Fluorescent DNA staining, electron microscopy (EM) observations, elemental analysis, and extraction of high-molecula...
Data
##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
Chapter
The permanent ice covers of liquid water based lakes in the McMurdo Dry Valleys are thermodynamically active and display a well defined but transitory stratigraphy. We discuss the annual development of the physical structure of the ice based on field measurements, data gathered during the austral winter and spring of 1994 and 1995, laboratory exper...
Chapter
A novel method of analyzing ice temperature records is applied to several years of data from Lake Hoare and Lake Bonney (Antarctica) to estimate vertical distributions of liquid water in the perennial ice covers at the end of summer melting seasons. Three years of ice temperature data at Lake Bonney (1993–1995) show that the ice contained 20% liqui...
Article
Perennial ice covers on many Antarctic lakes have resulted in high lake inorganic carbon contents. The objective of this paper was to evaluate and compare the brine and CO2 chemistries of Lake Vida (Victoria Valley) and West Lake Bonney (Taylor Valley), two lakes of the McMurdo Dry Valleys (East Antarctica), and their potential consequences during...
Poster
Full-text available
In a briny, frigid, inhospitable anoxic lake sealed beneath tens of meters of ice in Antarctica, there is a diverse microbial ecosystem. Lake Vida, one of the largest lakes in McMurdo Dry Valleys, Antarctica, is a thick block of ice permeated by brine channels below 16 m that contain very high levels of N2O (86.6 ± 5.9 μM). The surrounding sediment...
Article
Reservoir-river systems in desert environments may provide the optimal combination of environmental conditions (e.g. light, nutrients, temperature, and flow) that maximizes primary production in downstream reaches. Stream metabolism was measured using an open-system approach each month during spring-summer in a semi-arid tailwater (South Fork Humbo...
Poster
Full-text available
Lake Vida, one of the largest lakes in McMurdo Dry Valleys, Antarctica, is a 27 m thick block of ice permeated by brine channels below 16 m (Fig. 1). The subzero -13.4oC brine has an unusual geochemistry with high levels of iron, dissolved organic carbon, nitrate (NO3-), nitrous oxide (N2O) and ammonium (NH4+) (Table 1). Fifty-nine heterotrophic ba...
Article
Full-text available
The permanent ice cover of Lake Vida (Antarctica) encapsulates an extreme cryogenic brine ecosystem (-13 °C; salinity, 200). This aphotic ecosystem is anoxic and consists of a slightly acidic (pH 6.2) sodium chloride-dominated brine. Expeditions in 2005 and 2010 were conducted to investigate the biogeochemistry of Lake Vida's brine system. A phylog...
Article
Full-text available
The first winter in the life cycle of Antarctic krill Euphausia superba is a critical period in which larval survival and recruitment to the adult population are highly sensitive to environmental conditions, yet little is known about larval physiological dynamics during this period. An individual-based model was developed to investigate patterns of...
Article
Full-text available
Antarctic phytoplankton is characterized by a pronounced seasonality in abundance, driven mainly by changes in sunlight. We combined measurements and modeling to describe the influence of changing daylength on fall and winter phytoplankton production in coastal waters of the western Antarctic Peninsula (wAP) in 2001 and 2002. The model was paramete...
Article
This study used a portable spectrometer to assess the feasibility of using airborne hyperspectral imagery to map the dominant types and amounts of aquatic vegetation in the Carson and Truckee Rivers of western Nevada. Spectral reflectance data were acquired for a number of periphyton and macrophyte types, and corresponding vegetation samples were p...
Article
Lake Vida in the Victoria Valley of East Antarctica harbors ice-entrained brine that has been isolated from surface processes for several thousand years. The brine conditions (permanently dark, temperature of -13.4 °C, lack of oxygen, and pH of 6.2) and geochemistry are highly unusual. As an example, the brine contains excessive quantities of both...
Article
Lake Vida, the largest lake in the McMurdo Dry Valleys of Antarctica, has the thickest ice cover of any lake on Earth. In order to understand the controls on lake formation, and the antiquity of the ecosystem, 40 ground penetrating radar transects and two ice cores (21 and 26.5 m deep) were obtained in the fall of 2010. The ice cores are characteri...
Article
Full-text available
Most lakes in the McMurdo Dry Valleys are perennially covered with 3 to 6 m of ice, but Lake Vida is frozen from the surface through the lake bed, with ice permeated by brine channels. Brine collected from within the ice of Lake Vida is six times saltier than seawater, anoxic, with temperature of -13.4 C, pH of 6.2, high concentrations of ferrous i...
Conference Paper
The South Fork Humboldt River (Elko County, Nevada) represents an arid regulated river with enhanced nutrient loadings from upstream reservoir releases. The river below the reservoir is characterized as a shallow (<1m), low turbidity river dominated by filamentous algae (Cladophora), with observed eutrophic benthic algal conditions (algal biomass >...
Article
Full-text available
Understanding the flow of solar energy into ecosystems is fundamental to understanding ecosystem productivity and dynamics. To gain a better understanding of this fundamental process in the Antarctic winter sea ice, we produced a model that estimates the time-integrated exposure of seasonal Antarctic sea ice to PAR through the use of remotely sense...
Article
Full-text available
The freshwater stalked diatom, Didymosphenia geminata, has increased its proliferation in new and native ranges with the potential for significant ecological impacts to streams around the world. Uncertainty remains regarding the water chemistry in which D. geminata thrives despite recent advances in the understanding of its suitable physical habita...
Article
Full-text available
Sampling is conducted during 2006 in Lahontan Reservoir, Nevada to investigate seasonal variation of total mercury (THg) and methylmercury (MeHg) partitioning in different phytoplankton size fractions as a function of point source (fluvial) mercury (Hg) loads, reservoir residence time, and algal growth. Carson River Hg inputs into the reservoir are...
Article
Pack ice in the Bellingshausen Sea contained moderate to high stocks of microalgal biomass (3–10mgChlam−2) spanning the range of general sea-ice microalgal microhabitats (e.g., bottom, interior and surface) during the International Polar Year (IPY) Sea Ice Mass Balance in the Antarctic (SIMBA) studies. Measurements of irradiance above and beneath t...
Article
The South Fork Humboldt Reservoir (south of Elko, Nevada) represents an arid, hypolimnetic release dam with tail-water eutrophication exceeding 300mg Chla per m2. The USEPA model AQUATOX 3 has been used to simulate reservoir nutrient loadings on tail-water periphyton and to predict changes in stream response to top release conditions. From April to...
Article
This study documents the physico-chemical properties of newly formed sea ice at a frost flower site of the Ice Station `Belgica'. in the Bellingshausen Sea, (Sept-Oct 2007). Frost flower formation on sea ice is of interest, both for paleoclimatic reconstructions in deep ice cores and for potential impacts on atmospheric chemistry. The site has been...
Article
Many cold-adapted unicellular plants express ice-active proteins, but at present, only one type of such proteins has been described, and it shows no resemblance to higher plant antifreezes. Here, we describe four isoforms of a second and very active type of extracellular ice-binding protein (IBP) from a unicellular chlamydomonad alga collected from...
Article
Ice-sealed lakes, potentially home to novel microbiota and microbial processes, can provide a window into isolated and geologically ancient systems. These habitats are earth analogs for extraterrestrial systems that have yet to be sampled, though potentially harbor, or have harbored life at some time during their past. They are also small-scale mod...
Article
The geographic remoteness, the lack of remote sensing capabilities, and the lack of appropriate environmental sensors make the detection of seasonal trends or inter-annual variations in sea-ice microbial biomass or production processes within the pack ice of the Antarctic extremely rare. The evaluation of their inter-annual variability in the conte...
Article
Full-text available
To improve water quality and enhance habitat for fish and wildlife, a restoration project was initiated on the Truckee River at McCarran Ranch, Nevada. A water quality model was parameterized using Hydrologic Simulation Program-Fortran to represent the river's restored characteristics to test the hypothesis that restoration of the Truckee River imp...
Article
Full-text available
An internal ``gap'' layer of deteriorated sea ice is co-located with a significant microbial biological community in late first year and second year Antarctic sea ice in summer. We modeled gap layer formation using a thermal flux model based on the summer reversal in thermal gradient and the thermal conductivity found in the upper ice column. The c...
Article
Full-text available
Stable nitrogen isotopes (δ15N) and semipermeable membrane devices (SPMDs) were used together to provide evidence of potential anthropogenic connections to aquatic organisms in the Truckee River, which flows through the Reno/Sparks metropolitan area in Nevada. Crayfish, snail, and periphyton δ15N values, and SPMD toxicity data collected during high...
Book
Full-text available
There is now an increased awareness of the importance of polar regions in the Earth system, as well as their vulnerability to anthropogenic derived change, including of course global climate change. This text is the latest edition of this book and offers an introduction to polar ecology. It has been revised and updated, providing expanded coverage...
Article
Full-text available
The Nevada System of Higher Education (NSHE) was recently awarded funding from NASA's EPSCoR program to develop a broad strategy for field, remote and virtual exploration using planetary analog sites in Nevada and California. The work brings together researchers at the two state Universities, UNR and UNLV with faculty at both northern and southern...
Article
Full-text available
Aquatic foodweb models for 2 seasons (relatively high- [March] and low-flow [August] conditions) were constructed for 4 reaches on the Truckee River using delta C-13 and delta N-15 data from periphyton, macroinvertebrate, and fish samples collected in 2003 and 2004. The models were constructed with isotope values that included measured periphyton s...
Article
An Antarctic sea ice bacterium of the Gram-negative genus Colwellia, strain SLW05, produces an extracellular substance that changes the morphology of growing ice. The active substance was identified as a approximately 25-kDa protein that was purified through its affinity for ice. The full gene sequence was determined and was found to encode a 253-a...
Article
Because the Truckee River connects two lakes along the Eastern Sierra Nevada Mountains with different limiting nutrients, this research addresses whether the nitrogen:phosphorus (N:P) balance of the river ecosystem changes longitudinally. Historical (1990 to 2000) total nitro-gen:total phosphorus (TN:TP) ratios in river water exhibited the expected...
Article
Full-text available
Antarctic krill are a key species in the Southern Ocean ecosystem, and their life cycle appears to be correlated with, and by implication dependent upon, seasonal sea ice dynamics. Moving from correlations with environmental parameters to an understanding of the mechanisms that lead to these correlations may allow predictions of the consequences of...
Article
Lake Vida, located in the McMurdo Dry Valleys, Antarctica, is an 'ice-sealed' lake with approximately 19 m of ice covering a highly saline water column (approximately 245 ppt). The lower portions of the ice cover and the lake beneath have been isolated from the atmosphere and land for circa 2800 years. Analysis of microbial assemblages within the p...
Article
Full-text available
Nutrient loads enter the lower Truckee River of western Nevada, affecting the growth of attached algae (periphyton) which causes depressed nighttime dissolved oxygen (DO) levels. The lower Truckee River is home to the endangered cui-ui and threatened Lahontan cut-throat trout, with DO standards being established to in part protect these species. Hy...
Article
Full-text available
Rock, soil, and ice penetration by coring, drilling or abrading is of great importance to a large number of space and earth applications. Proven techniques to sample Mars subsurface will be critical for future NASA astrobiology missions that will search for records of past and present life on the planet. An Ultrasonic/Sonic Drill/Corer (USDC) has b...
Article
Antarctica contains a number of permanently ice-covered lakes which have often been used as analogs of purported lakes on Mars in the past. Antarctic subglacial lakes, such as Lake Vostok, have also been viewed as excellent analogs for an ice covered ocean on the Jovian moon Europa, and to a lesser extend on Mars. Lakes in the McMurdo Dry Valleys o...
Article
The Carson River originates in eastern Alpine County California, flows northeast into western Nevada through Carson City, and terminates in the Carson Sink. Elevated nutrient levels from agricultural return flows allow for excess attached algal (periphyton) growth. Periods of low flow, coupled with an abundance of periphyton, harbor an environment...