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Isotopic Discrimination In The Double-Crested Cormorant (Phalacrocorax Auritus), Elizabeth C. Craig, Brian S. Dorr, Katie C. Hanson-Dorr, Jed P. Sparks, Paul D. Curtis Oct 2015

Isotopic Discrimination In The Double-Crested Cormorant (Phalacrocorax Auritus), Elizabeth C. Craig, Brian S. Dorr, Katie C. Hanson-Dorr, Jed P. Sparks, Paul D. Curtis

Brian S Dorr

The diet-tissue discrimination factor is the amount by which a consumer’s tissue varies isotopically from its diet, and is therefore a key element in models that use stable isotopes to estimate diet composition. In this study we measured discrimination factors in blood (whole blood, red blood cells and plasma), liver, muscle and feathers of Double- crested Cormorants (Phalacrocorax auritus) for stable isotope ratios of carbon, nitrogen and sulfur. Cormorants exhibited discrimination factors that differed significantly among tissue types (for carbon and nitrogen), and differed substantially (in the context of the isotopic variation among relevant prey species) from those observed in …


Influence Of Simulated Double-Crested Cormorant, Phalacrocorax Auritus, Predation On Multiple-Batch Production Of Channel Catfish, Ictalurus Punctatus, Brian S. Dorr, Carole R. Engle Jun 2015

Influence Of Simulated Double-Crested Cormorant, Phalacrocorax Auritus, Predation On Multiple-Batch Production Of Channel Catfish, Ictalurus Punctatus, Brian S. Dorr, Carole R. Engle

Brian S Dorr

The double-crested cormorant, Phalacrocorax auritus, is considered the primary depredating bird species on commercially produced channel catfish, Ictalurus punctatus, in the southeastern USA. We simulated different levels of cormorant predation on losses at harvest and economic effects on channel catfish production in a multiple-batch cropping system. We observed significant (P<0.05) declines in catfish production at increasing levels of cormorant predation in this study. This decline was mitigated by increased individual growth of catfish at higher predation rates (i.e., lower catfish densities). This mitigating effect produced a non-linear relationship with total kg of catfish harvested per pond resulting in a non-linear incremental increase in breakeven price related to predation. Costs of production ($/kg) increased with increasing predation levels up to very high levels of predation with a cumulative maximum increase in breakeven price of $0.143/kg. These results indicate that losses at harvest due to cormorant predation occur immediately but are mitigated in part by compensatory growth of individual catfish. Losses due to cormorant predation in multi-batch systems can be considerable, but there is not a 1:1 relationship between losses and kg of catfish harvested due to compensatory actors.


Influence Of Current Land Use And Edaphic Factors On Arbuscular Mycorrhizal (Am) Hyphal Abundance And Soil Organic Matter In And Near Serengeti National Park, Geofrey Soka, Mark Ritchie, Emilian Mayemba May 2015

Influence Of Current Land Use And Edaphic Factors On Arbuscular Mycorrhizal (Am) Hyphal Abundance And Soil Organic Matter In And Near Serengeti National Park, Geofrey Soka, Mark Ritchie, Emilian Mayemba

Geofrey Soka

Arbuscular mycorrhizal fungi (AMF) are important microbial symbionts for plants especially when soil phosphorus (P) and nitrogen (N) are limited. Little is known about the distribution of AM hyphae in natural systems of tropical soils across landscapes and their association with different land uses. We studied mycorrhizal hyphal abundance in a wildlife grazed system, a livestock grazed system and under cultivated soils in and near Serengeti National Park, Tanzania. Samples of the upper 15 cm of soil beneath locally dominant plant species were collected. Hyphae were preserved on permanent slides and the length of hyphae per cubic centimeter of soil …


Impacts Of Colonial Waterbirds On Vegetation And Potential Restoration Of Island Habitats, Christopher R. Ayers, Katie C. Hanson-Dorr, Sadie O'Dell, Charles D. Lovell, Michael L. Jones, Jason R. Suckow, Brian S. Dorr May 2015

Impacts Of Colonial Waterbirds On Vegetation And Potential Restoration Of Island Habitats, Christopher R. Ayers, Katie C. Hanson-Dorr, Sadie O'Dell, Charles D. Lovell, Michael L. Jones, Jason R. Suckow, Brian S. Dorr

Brian S Dorr

Colonial waterbirds have impacted forested island ecosystems throughout their breeding range, changing vegetation, and soil characteristics and bird communities.Our objectives were to (1) determine effects of three levels of colonial waterbird exclusion on overall vegetation diversity and growth, and survival of a candidate restoration species (black elderberry; Sambucus nigra canadensis); (2) investigate effects of different planting techniques on survival and growth of black elderberry; and (3) determine effects of waterbird colonization on soil chemistry. In 2012, we investigated effects of three levels of waterbird exclusion (none control plots [CON]; partial, which excluded waterbirds larger than gulls [PEX]; and full which …


Wintering Ecology Of Adult North American Ospreys, Brian E. Washburn, Charles J. Henny, Mark S. Martell, Richard O. Bierregaard, Brian S. Dorr, Thomas J. Olexa Dec 2014

Wintering Ecology Of Adult North American Ospreys, Brian E. Washburn, Charles J. Henny, Mark S. Martell, Richard O. Bierregaard, Brian S. Dorr, Thomas J. Olexa

Brian S Dorr

North American Ospreys (Pandion haliaetus) typically migrate long distances to their wintering grounds in the tropics. Beyond the general distribution of their wintering range (i.e., the Caribbean, South America, and Central America), very little is known about the wintering ecology of these birds. We used satellite telemetry to determine the duration of wintering period, to examine the characteristics of wintering areas used by Ospreys, and to quantify space use and activity patterns of wintering Ospreys. Adult Ospreys migrated to wintering sites and exhibited high wintering site fidelity among years. Overall, Ospreys wintered on river systems (50.6%) more than on lakes …


Mass And Nutrient Loss In Decaying Hardwood Boles At Hubbard Brook, Chris E. Johnson Jul 2014

Mass And Nutrient Loss In Decaying Hardwood Boles At Hubbard Brook, Chris E. Johnson

Chris E Johnson

No abstract provided.


Effects Of Prey Abundance On Breeding Season Diet Of Northern Goshawks (Accipiter Gentilis) Within An Unusual Prey Landscape, Robert A. Miller, Jay D. Carlisle, Marc J. Bechard Mar 2014

Effects Of Prey Abundance On Breeding Season Diet Of Northern Goshawks (Accipiter Gentilis) Within An Unusual Prey Landscape, Robert A. Miller, Jay D. Carlisle, Marc J. Bechard

Robert Miller

A critical element of diet analysis is species adaptability to alternative prey sources. The breeding season diet of Northern Goshawks (Accipiter gentilis) includes both mammalian and avian species, varies geographically, and is often dependent upon tree squirrels of the genera Sciurus and Tamiasciurus>/i>. We studied alternative prey sources of Northern Goshawks in the South Hills of south-central Idaho, an area where tree squirrels are naturally absent and other prey frequently important in the diet of goshawks, such as smaller corvids, are uncommon. We quantified the diet of goshawks using nest cameras and surveyed abundance of prey using line …


Recreating Mesquite Mounds (Nebkas) In The Colorado Desert, David A. Bainbridge Jan 2014

Recreating Mesquite Mounds (Nebkas) In The Colorado Desert, David A. Bainbridge

David A Bainbridge

Accretion dunes or mounds (also known as nebkas or nebkhas) are formed when plants capture and then are partially buried in wind-blown sand. In the San Felipe drainage in the western Colorado Desert, mesquite (Prosopis glandulosa Torrey var. torreyana (L. D. Benson) M. C. Johnston)) forms dunes up to 5 m high. These are ecologically important for both ecosystem structure (primarily habitat) and function (soil accumulation, moisture retention and nutrient cycling). The widening of California state highway 86 damaged and removed several mesquite mounds and the California Department of Transportation asked us to explore techniques for recreating them to reduce …


Water Stress Strengthens Mutualism Among Ants, Trees, And Scale Insects, Elizabeth G. Pringle, Erol Akc¸Ay, Ted K. Raab, Rodolfo Dirzo, Deborah M. Gordon Nov 2013

Water Stress Strengthens Mutualism Among Ants, Trees, And Scale Insects, Elizabeth G. Pringle, Erol Akc¸Ay, Ted K. Raab, Rodolfo Dirzo, Deborah M. Gordon

Ted K. Raab

Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant–plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners’ investments in a widespread ant–plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the …


Will Hubbard Brook Soils Be A Source Or Sink Of Carbon In A Changing Climate?, Chris E. Johnson Jul 2013

Will Hubbard Brook Soils Be A Source Or Sink Of Carbon In A Changing Climate?, Chris E. Johnson

Chris E Johnson

No abstract provided.


The Contribution Of Fe (Iii) And Humic Acid Reduction To Ecosystem Respiration In Drained Thaw Lake Basins Of The Arctic Coastal Plain, David A. Lipson, Ted K. Raab, Dominic Goria, Jaime Zlamal May 2013

The Contribution Of Fe (Iii) And Humic Acid Reduction To Ecosystem Respiration In Drained Thaw Lake Basins Of The Arctic Coastal Plain, David A. Lipson, Ted K. Raab, Dominic Goria, Jaime Zlamal

Ted K. Raab

Previous research showed that anaerobic respiration using iron (Fe) oxides as terminal electron acceptor contributed substantially to ecosystem respiration (ER) in a drained thaw lake basin (DTLB) on the Arctic coastal plain. As DTLB age, the surface organic layer thickens, progressively burying the Fe-rich mineral layers. We therefore hypothesized that Fe (III) availability and Fe reduction would decline with basin age. We studied four DTLB across an age gradient, comparing seasonal changes in the oxidation state of dissolved and extractable Fe pools and the estimated contribution of Fe reduction to ER. The organic layer thickness did not strictly increase with …


Metagenomic Insights Into Anaerobic Metabolism Along An Arctic Peat Soil Profile, David A. Lipson, John M. Haggerty, Archana Srinivas, Ted K. Raab, Shashank Sathe, Elizabeth A. Dinsdale May 2013

Metagenomic Insights Into Anaerobic Metabolism Along An Arctic Peat Soil Profile, David A. Lipson, John M. Haggerty, Archana Srinivas, Ted K. Raab, Shashank Sathe, Elizabeth A. Dinsdale

Ted K. Raab

A metagenomic analysis was performed on a soil profile from a wet tundra site in northern Alaska. The goal was to link existing biogeochemical knowledge of the system with the organisms and genes responsible for the relevant metabolic pathways. We specifically investigated how the importance of iron (Fe) oxides and humic substances (HS) as terminal electron acceptors in this ecosystem is expressed genetically, and how respiratory and fermentative processes varied with soil depth into the active layer and into the upper permafrost. Overall, the metagenomes reflected a microbial community enriched in a diverse range of anaerobic pathways, with a preponderance …


Diversity Of Plants And Animals In Mountain Systems In Tajikistan, Victor Roy Squires Dr, Neymatalo Safarov Dr Jan 2013

Diversity Of Plants And Animals In Mountain Systems In Tajikistan, Victor Roy Squires Dr, Neymatalo Safarov Dr

Victor Roy Squires Dr

Tajikistan, a landlocked country, is one of the world's centers of origin of cultivated plants and has a special role in the conservation of mountain biodiversity. The richness of biodiversity shows up at the genetic, species, population, and ecosystem levels. There are many relic and endemic species, with most of the components of biodiversity vulnerable to anthropogenic factors. Close cooperation across borders will be required for conservation of unique and threatened ecosystems in the Central Asian region. Proximate threats such as poaching, overfishing, illegal logging and overgrazing are causing irreversible damage to biodiversity in the Tajikistan hotspot. Threats stem from …


Classification Of The Alterations Of Beaver Dams To Headwater Streams In Northeastern Connecticut, U.S.A., Denise Burchsted, Melinda D. Daniels Jan 2013

Classification Of The Alterations Of Beaver Dams To Headwater Streams In Northeastern Connecticut, U.S.A., Denise Burchsted, Melinda D. Daniels

Denise Burchsted

Of the many types of barriers to water flow, beaver dams are among the smallest, typically lasting less than a decade and rarely exceeding 1.5 m in height. They are also among the most frequent and common obstructions in rivers, with a density often exceeding ten dams per km, a frequency of construction within a given network on a time scale of years, and a historic extent covering most of North America. Past quantification of the geomorphologic impact of beaver dams has primarily been limited to local impacts within individual impoundments and is of limited geographic scope. To assess the …


Insights Into Forest Soil Carbon Dynamics From Nuclear Magnetic Resonance Spectroscopy, Chris E. Johnson Jan 2013

Insights Into Forest Soil Carbon Dynamics From Nuclear Magnetic Resonance Spectroscopy, Chris E. Johnson

Chris E Johnson

No abstract provided.


Evidence That Glucose Is The Major Transferred Metabolite In Dinoflagellate–Cnidarian Symbiosis, Matthew S. Burriesci, Ted K. Raab, John R. Pringle Oct 2012

Evidence That Glucose Is The Major Transferred Metabolite In Dinoflagellate–Cnidarian Symbiosis, Matthew S. Burriesci, Ted K. Raab, John R. Pringle

Ted K. Raab

Reef-building corals and many other cnidarians are symbiotic with dinoflagellates of the genus Symbiodinium. It has long been known that the endosymbiotic algae transfer much of their photosynthetically fixed carbon to the host and that this can provide much of the hostʼs total energy. However, it has remained unclear which metabolite(s) are directly translocated from the algae into the host tissue. We reexamined this question in the small sea anemone Aiptasia using labeling of intact animals in the light with 13C-bicarbonate, rapid homogenization and separation of animal and algal fractions, and analysis of metabolite labeling by gas chromatography-mass spectrometry. We …


Recovery Of Sensitive Watersheds In The Northeastern United States From Chronic Acidification: The Role Of Soil Chemistry, Chris E. Johnson Jul 2012

Recovery Of Sensitive Watersheds In The Northeastern United States From Chronic Acidification: The Role Of Soil Chemistry, Chris E. Johnson

Chris E Johnson

No abstract provided.


Double-Crested Cormorant Distribution On Catfish Aquaculture In The Yazoo River Basin Of Mississippi, Brian S. Dorr, Loren W. Burger, Scott C. Barras, Kristina Casscles Godwin Mar 2012

Double-Crested Cormorant Distribution On Catfish Aquaculture In The Yazoo River Basin Of Mississippi, Brian S. Dorr, Loren W. Burger, Scott C. Barras, Kristina Casscles Godwin

Brian S Dorr

No abstract provided.


Water Table Height And Microtopography Control Biogeochemical Cycling In An Arctic Coastal Tundra Ecosystem, David A. Lipson, Donatella Zona, Ted K. Raab, Francis Bozzolo, Marguerite Mauritz, Walter C. Oechel Jan 2012

Water Table Height And Microtopography Control Biogeochemical Cycling In An Arctic Coastal Tundra Ecosystem, David A. Lipson, Donatella Zona, Ted K. Raab, Francis Bozzolo, Marguerite Mauritz, Walter C. Oechel

Ted K. Raab

Drained thaw lake basins (DTLB’s) are the dominant land form of the Arctic Coastal Plain in northern Alaska. The presence of continuous permafrost prevents drainage and so water tables generally remain close to the soil surface, creating saturated, suboxic soil conditions. However, ice wedge polygons produce microtopographic variation in these landscapes, with raised areas such as polygon rims creating more oxic microenvironments. The peat soils in this ecosystem store large amounts of organic carbon which is vulnerable to loss as arctic regions continue to rapidly warm, and so there is great motivation to understand the controls over microbial activity in …


Efficacy, Effort, And Cost Comparisons Of Trapping And Acetaminophen-Baiting For Control Of Brown Treesnakes On Guam, Larry Clark, Peter J. Savarie, John A. Shivik, Stewart W. Breck, Brian S. Dorr Jan 2012

Efficacy, Effort, And Cost Comparisons Of Trapping And Acetaminophen-Baiting For Control Of Brown Treesnakes On Guam, Larry Clark, Peter J. Savarie, John A. Shivik, Stewart W. Breck, Brian S. Dorr

Brian S Dorr

Abstract: Brown treesnakes (Boiga irregularis) are an invasive species to the island of Guam. Because they have extirpated the native forest avifauna on Guam and are a threat to other Pacific islands, the development of efficient and cost-effective methods to control them is desired. We compared the efficacy, cost, and effort required to remove brown treesnakes on 6-ha plots in forest scrub on Guam, using 2 methods: trapping and poison baiting. Toxic baits consisted of dead neonatal mice adulterated with 80-mg acetaminophen. To assess efficacy, we used mark-recapture methods to estimate snake abundance on plots 12 days before and 12 …


The Direction Of Research And Management Of Double-Crested Cormorants Heading Into The 2000s: Symposium Overview And Future Information Needs, Brian S. Dorr, Christopher Somers Jan 2012

The Direction Of Research And Management Of Double-Crested Cormorants Heading Into The 2000s: Symposium Overview And Future Information Needs, Brian S. Dorr, Christopher Somers

Brian S Dorr

Abstract.—An overview is provided of a symposium on the direction of research and management of Double-crested Cormorants (Phalacrocorax auritus) heading into the 2000s. The current symposium built on previous efforts and described a number of focus areas of informational need, including cormorant impacts on natural resources, demographics of cormorants, assessment of control efforts, assessment of fish consumption and bioenergetics, and cormorant spatial ecology and influences on movements. The cormorant symposium highlighted a shift in research focus relative to earlier symposia, from evaluating potential impacts on commercial and natural resources to evaluating management actions in attaining desired goals. In addition, the …


Modification Of Net Configurations Of The Coda Netlauncher© To Enhance Bird Capture, Amanda M. Prisock, Brian S. Dorr, James C. Cumbee Jan 2012

Modification Of Net Configurations Of The Coda Netlauncher© To Enhance Bird Capture, Amanda M. Prisock, Brian S. Dorr, James C. Cumbee

Brian S Dorr

Abstract: We modified and evaluated capture nets fi red from the Coda Netlauncher® as a tool for capturing various avian species. We modified the netlauncher by using customized nets to maximize the area of the capture zone. We captured 137 birds, comprising 12 species, in 23 attempts between July 2008 and October 2009 using this method. Capture success rates varied from 25 to 69% were comparable to success rates reported for other capture methods for these species. However, individual capture success for different net configurations varied greatly from 3 to 65%. Minimal injuries and 2 bird fatalities were reported. The …


Management Of Double-Crested Cormorants To Improve Sport Fisheries In Michigan: Three Case Studies, Brian S. Dorr, Shauna L. Hanisch, Peter H. Butchko, David G. Fielder Jan 2012

Management Of Double-Crested Cormorants To Improve Sport Fisheries In Michigan: Three Case Studies, Brian S. Dorr, Shauna L. Hanisch, Peter H. Butchko, David G. Fielder

Brian S Dorr

No abstract provided.


Towards Optimized Population Control Efficiency In Space And Time: A Modelling Framework Adapted To A Colonial Waterbird, Alban Guillaumet, Brian S. Dorr, Guiming Wang Jan 2012

Towards Optimized Population Control Efficiency In Space And Time: A Modelling Framework Adapted To A Colonial Waterbird, Alban Guillaumet, Brian S. Dorr, Guiming Wang

Brian S Dorr

The double-crested cormorant is a native North American waterbird that recently underwent a dramatic population expansion. Population control efforts in the USA and Canada attempt to mitigate cormorant damages to natural resources and aquaculture. However, there is currently no coordination among the various stakeholders involved in management activities as well as no attempt to optimize population control efficiency. In this paper, we present for the first time a spatially explicit stage-structured metapopulation model parameterized for the cormorant. We developed simulation tools to get insights into the efficiency gain that can be expected from a better planning of management activities in …


Summer And Migrational Movements Of Satellite-Marked Double-Crested Cormorants From A Breeding Colony Managed By Egg-Oiling In Lake Ontario, Usa, Brian S. Dorr, Jimmy D. Taylor Ii, Scott J. Werner, D. Tommy King, James F. Farquhar, Irene M. Mazzocchi, Russell D. Mccullough Jan 2012

Summer And Migrational Movements Of Satellite-Marked Double-Crested Cormorants From A Breeding Colony Managed By Egg-Oiling In Lake Ontario, Usa, Brian S. Dorr, Jimmy D. Taylor Ii, Scott J. Werner, D. Tommy King, James F. Farquhar, Irene M. Mazzocchi, Russell D. Mccullough

Brian S Dorr

Abstract.—A two-year satellite telemetry study was initiated in May 2000 at a Double-crested Cormorant (Phalacrocorax auritus) breeding colony on Little Galloo Island (LGI) in eastern Lake Ontario, New York, USA, which is managed by egg-oiling. The objective was to describe cormorant (N = 26/year) movements, specifically during the period of reproductive management by egg-oiling and seasonally (breeding, migration and wintering). Egg-oiling at two-week intervals resulted in a hatch success on LGI of 5.7% for 2000 and 2001, combined. The majority (97%) of core use areas of marked cormorants contained LGI throughout three egg-oiling treatments (six weeks), and 71% still contained …


Determinants Of Local And Migratory Movements Of Great Lakes Double-Crested Cormorants, Alban Guillaumet, Brian S. Dorr, Guiming Wang, Jimmy D. Taylor Ii, Richard B. Chipman, Heidi Scherr, Jeff Bowman, Kenneth F. Abraham, Terry J. Doyle, Elizabeth Cranker Jun 2011

Determinants Of Local And Migratory Movements Of Great Lakes Double-Crested Cormorants, Alban Guillaumet, Brian S. Dorr, Guiming Wang, Jimmy D. Taylor Ii, Richard B. Chipman, Heidi Scherr, Jeff Bowman, Kenneth F. Abraham, Terry J. Doyle, Elizabeth Cranker

Brian S Dorr

We investigated how individual strategies combine with demographic and ecological factors to determine local and migratory movements in the double-crested cormorants (Phalacrocorax auritus). One hundred and forty-five cormorants were captured from 14 nesting colonies across the Great Lakes area and fitted with satellite transmitters. We first tested the hypotheses that sexual segregation, density-dependent effects, and the intensity of management operations influenced home range size during the breeding season. The influence of these factors appeared to be limited in part due to random variability in foraging and dispersal decisions at individual and colony levels. We also designed a statistical framework to …


Detection And Characterization Of A Distinct Bornavirus Lineage From Healthy Canada Geese (Branta Canadensis), John A. Baroch Jan 2011

Detection And Characterization Of A Distinct Bornavirus Lineage From Healthy Canada Geese (Branta Canadensis), John A. Baroch

John A Baroch

Avian bornaviruses (ABV), identified in 2008, infect captive parrots and macaws worldwide. The natural reservoirs of these viruses are unknown. Reverse transcription-PCR (RT-PCR) was used to screen oropha- ryngeal/cloacal swab and brain samples from wild Canada geese (Branta canadensis) for ABV. Approximately 2.9% of swab samples were positive for bornavirus sequences. Fifty-two percent of brain samples from 2 urban flocks also tested positive, and brain isolates were cultured in duck embryo fibroblasts. Phylogenetic analyses placed goose isolates in an independent cluster, and more notably, important regulatory sequences present in Borna disease virus but lacking in psittacine ABVs were present in …


Ameliorating The Effects Of The Digenetic Trematode, Bolbophorus Damnificus On The Channel Catfish Industry, Lester Khoo, David J. Wise, Linda M. Pote, Andrew J. Mitchell, Todd S. Byars, Marlena C. Yost, Cynthia M. Doffitt, Brian S. Dorr Jan 2011

Ameliorating The Effects Of The Digenetic Trematode, Bolbophorus Damnificus On The Channel Catfish Industry, Lester Khoo, David J. Wise, Linda M. Pote, Andrew J. Mitchell, Todd S. Byars, Marlena C. Yost, Cynthia M. Doffitt, Brian S. Dorr

Brian S Dorr

No abstract provided.


The Composite Insect Trap: An Innovative Combination Trap For Biologically Diverse Sampling, Laura Russo, Rachel Stehouwer, J. Heberling, Katriona Shea Jan 2011

The Composite Insect Trap: An Innovative Combination Trap For Biologically Diverse Sampling, Laura Russo, Rachel Stehouwer, J. Heberling, Katriona Shea

Mason Heberling

No abstract provided.


Reduction Of Iron (Iii) And Humic Substances Plays A Major Role In Anaerobic Respiration In An Arctic Peat Soil, David A. Lipson, Mony Jha, Ted K. Raab, Walter C. Oechel Dec 2010

Reduction Of Iron (Iii) And Humic Substances Plays A Major Role In Anaerobic Respiration In An Arctic Peat Soil, David A. Lipson, Mony Jha, Ted K. Raab, Walter C. Oechel

Ted K. Raab

Arctic peat soils contain vast reserves of organic C and are largely anaerobic. However, anaerobic respiration, particularly the role of Fe(III) and humic substances as electron acceptors, is not well understood in such ecosystems. We investigated these processes in a drained thaw lake basin on the Arctic coastal plain near Barrow, Alaska. We measured concentrations of soluble Fe and other potential electron acceptors, described the microbial community, and performed experiments in the laboratory and field to measure net rates of Fe(III) reduction and the relationship of this process to C cycling. In most areas within the basin, aerobic conditions existed …