2009 LTER All Scientists Meeting - Movement of Organic Matter

The propagating response of inner shelf circulation to wind relaxations along the central California Coast

Libe Washburn — Thu, 10 Sep 2009 14:38:43 +0000

Poster Number:

395

Presenter/Primary Author:

Libe Washburn

Co-Authors:

Chris Melton

Co-Authors:

Melanie Fewings

Co-Authors:

Chris Gotschalk

Following relaxations prevailing equatorward winds, warm water from the Santa Barbara Channel flows poleward around Point Conception and along the central California coast. Sequences of satellite sea surface temperature images show the events as bands of warm water extending up to 20 km offshore. Characteristics of these flows were examined using time series of currents and temperature from an array of moorings along the inner shelf (15 m depth), a mooring on the mid-shelf (100 m depth), and surface current observations from high frequency radars.

Feeding by the Oribatid Mite Scheloribates Alters Microbial Activity and Carbon Cycling

Kyle Wickings — Wed, 09 Sep 2009 22:25:02 +0000

Poster Number:

392

Presenter/Primary Author:

Kyle Wickings

Co-Authors:

Stuart Grandy

Oribatid mites are among the most diverse soil mesofauna, and they possess a variety of metabolic and morphological feeding adaptations. Unfortunately, our understanding of the mechanisms by which oribatids may influence decomposition dynamics is incomplete. A microcosm experiment was conducted in which corn and oak leaf litter were incubated in the presence and absence of actively feeding oribatid mites Scheloribates sp. Our objective was to quantify the effects of Scheloribates sp. on microbial activity and carbon cycling within litter.

Soil Organic Matter Responses to Chronic Nitrogen Additions at the Harvard Forest

Richard Bowden — Wed, 02 Sep 2009 19:06:01 +0000

Poster Number:

382

Presenter/Primary Author:

Richard Bowden

Co-Authors:

Serita D. Frey

Co-Authors:

Scott Ollinger

Co-Authors:

Rich Maclean

Co-Authors:

Michelle Day

Co-Authors:

Knute Nadelhoffer

Co-Authors:

Jim LeMoine

Co-Authors:

Adrien Finzi

Co-Authors:

Edward Brzostek

Co-Authors:

Christy Goodale

Co-Authors:

April Melvin

Co-Authors:

Marissa Weiss

The Chronic Nitrogen Addition Experiment at the Harvard Forest was initiated in 1988 to better understand the process of forest N saturation due to anthropogenic N deposition. Presently, there is great interest in understanding and quantifying impacts of deliberate (forest fertilization) or inadvertent (atmospheric deposition) additions of nitrogen on forest growth as a means to enhance forest uptake of atmospheric C and subsequent storage within biomass and soil.

Aeolian flux of microorganisms in the McMurdo Dry Valleys, Antarctica

Marie Sabacka — Wed, 02 Sep 2009 00:38:14 +0000

Poster Number:

380

Presenter/Primary Author:

Marie Sabacka

Co-Authors:

John C. Priscu

Co-Authors:

Mark C. Greenwood

The McMurdo Dry Valleys in Antarctica (MCM) forms one of the most extreme deserts on Earth. It consists of a mosaic of permanently ice-covered lakes, ephemeral streams, exposed soils, and glaciers. Microorganisms are the only life forms occupying these landscape units. Given the relatively low and seasonal growth rates of these organisms, we contend that the distribution of microorganisms within this environment is controlled by physical factors.

Student Poster:

Yes

Niwot Ridge LTER Program: Alpine Ecosystems as Early Warning Systems

Mark Williams — Tue, 01 Sep 2009 17:42:43 +0000

Poster Number:

377

Presenter/Primary Author:

Mark Williams

Co-Authors:

Tim Seastedt

Co-Authors:

Diane McKnight

Co-Authors:

Alan Townsend

Co-Authors:

Bill Bowman

Co-Authors:

Steve Schmidt

Co-Authors:

Peter Blanken

The Niwot Ridge (NWT) LTER site was one of the five original LTER sites established in 1980. The LTER program is based at the University of Colorado-Boulder and is administered through the Institute of Arctic and Alpine Research (INSTAAR) and in cooperation with the Mountain Research Station, with special use permits from the US Forest Service.

Determining organic matter sources to CH4 production and bubbling from Alaskan lakes using stable isotopes and radiocarbon ages

Laura Brosius — Tue, 01 Sep 2009 00:46:24 +0000

Poster Number:

363

Presenter/Primary Author:

Laura Brosius

Co-Authors:

Katey Walter

Co-Authors:

Jeff Chanton

Methane production in Siberian thaw lakes is estimated to be 3.8 Tg CH4 yr -1. When entered into global models, this estimate increases northern wetland CH4 emissions (<6-40 Tg CH4 yr -1) by 10-63% (Walter et al 2006). Methane release of this magnitude from Siberian and other northern lakes, such as those in Alaska, may be linked to the rich carbon resources available to sediment-dwelling methanogens.

Student Poster:

Yes

Alder strategies for phosphorus assimilation across a boreal forest successional sequence

Michaela Swanson — Mon, 31 Aug 2009 21:14:19 +0000

Poster Number:

355

Presenter/Primary Author:

Michaela Swanson

Co-Authors:

Roger Ruess

Co-Authors:

Karl Olson

Co-Authors:

Knut Kielland

Co-Authors:

Lee Taylor

Co-Authors:

Jack McFarland

Ecosystem processes in northern systems depend heavily on inputs of biologically fixed nitrogen (N) from A. tenuifolia, which contributes the majority of N accumulated during boreal forest succession. However because of the high phosphorus (P) demands of this plant, we hypothesize that N-fixation inputs are controlled by the ability of alder to assimilate P through associations with ectomycorrhizal fungi (EMF), which produce enzymes that mobilize organic and recalcitrant P forms.

Student Poster:

Yes

Arctic LTER: Goals and Results

John Hobbie — Mon, 31 Aug 2009 20:38:57 +0000

Poster Number:

347

Presenter/Primary Author:

John Hobbie

Co-Authors:

George Kling

Co-Authors:

Chris Luecke

Co-Authors:

Gus Shaver

Co-Authors:

Anne Giblin

Co-Authors:

Donie Bret-Harte

The goal of the Arctic LTER is to predict the future ecological characteristics of Arctic Alaska based upon our knowledge of the controls of ecosystem structure and function as exerted by physical setting and geologic factors, climatic factors, biotic factors, and the changes in fluxes of water and materials from land to water.

Dynamics of Water-Stable Soil Aggregates in Arctic Soils

Rodney Simpson — Mon, 31 Aug 2009 18:57:16 +0000

Poster Number:

336

Presenter/Primary Author:

Rodney Simpson

Co-Authors:

John C. Moore

Co-Authors:

Johan Six

Arctic warming has been linked to changes in carbon cycling in this region. Cold temperatures and anoxic conditions in the Arctic inhibit microbial activity, lowering decomposition rates. As a result mineralization rates are low, resulting in nitrogen-limited-system, further reducing biological activity. Evidence has shown that eliminating this constraint on nutrient availability results in a vegetation shift and loss of soil carbon; however, the mechanisms behind soil carbon loss are not understood.

Student Poster:

Yes

Linking Carbon Quality to In-stream Nitrogen Processing, Boulder Creek, Colorado

Rebecca Barnes — Mon, 31 Aug 2009 18:49:27 +0000

Poster Number:

335

Presenter/Primary Author:

Rebecca Barnes

Co-Authors:

Richard L. Smith

Dissolved organic matter (DOM) dominates the material and energy fluxes within aquatic ecosystems. Carbon fuels the majority of microbial processes, including those that regulate in-stream nitrogen constituents. DOM sources and in situ transformations determine its chemical nature and lability within aquatic systems. Boulder Creek, which is located in the Colorado Front Range and spans an ecosystem gradient from the Continental Divide to the high plains, receives excess atmospheric nitrogen deposition due to its proximity to population centers and agricultural lands.