Karita Negandhi

Karita Negandhi
Macquarie University · Department of Earth and Planetary Sciences

PhD Univ. Quebec-INRS-ETE

About

18
Publications
3,313
Reads
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305
Citations
Additional affiliations
June 2015 - present
Macquarie University
Position
  • PostDoc Position
Description
  • Measuring and distinguishing CH4 emissions from anthropogenic and natural sources
September 2009 - February 2014
Institut National de la Recherche Scientifique
Position
  • PhD Student
Description
  • Studied links between Arctic thaw pond microbial communities and their greenhouse gas emissions
August 2006 - August 2009
Nova Southeastern University
Position
  • Master's Student
Description
  • Investigated the presence of coral disease associated bacteria within Florida reef sponges

Publications

Publications (18)
Article
Full-text available
Sponges can filter large volumes of seawater and accumulate highly diverse and abundant microbial communities within their tissue. Culture-independent techniques such as fluorescent in situ hybridization (FISH), 16S small subunit (SSU) rRNA gene analyses, and transmission electron microscopy (TEM) were applied to characterize the presence and distr...
Article
Full-text available
Permafrost thawing in lowland Arctic tundra results in a polygonal patterned landscape and the formation of numerous small ponds. These ponds emit biologically mediated carbon dioxide (CO2) and methane (CH4). Their greenhouse gas (GHG) emissions are variable, for reasons that are not well understood. Emissions are related to a balance between GHG p...
Article
Full-text available
A methane (CH4) and carbon dioxide (CO2) release experiment was held from April to June 2015 at the Ginninderra Controlled Release Facility in Canberra, Australia. The experiment provided an opportunity to compare different emission quantification techniques against a simulated CH4 and CO2 point source release, where the actual release rates were u...
Article
Full-text available
There is a growing interest in how the management of 'blue carbon' sequestered by coastal wetlands can influence global greenhouse gas (GHG) budgets. A promising intervention is through restoring tidal exchange to impounded coastal wetlands for reduced methane (CH4) emissions. We monitored an impounded wetland's GHG flux (CO2 and CH4) prior to and...
Article
Full-text available
Thawing permafrost in the Canadian Arctic tundra leads to peat erosion and slumping in narrow and shallow runnel ponds that surround more commonly studied polygonal ponds. Here we compared the methane production between runnel and polygonal ponds using stable isotope ratios, (14)C signatures, and investigated potential methanogenic communities thro...
Article
Full-text available
Permafrost thawing mobilizes large quantities of organic carbon that was sequestered in Arctic regions over the last glacial cycle. Processes involved in the oxidation of this carbon need to be further assessed to estimate the fraction to be released into the atmosphere. Shallow tundra ponds are sites of active carbon turnover on the landscape and...
Article
Full-text available
There is a growing interest in how the management of 'blue carbon' sequestered by coastal wetlands can influence global greenhouse gas (GHG) budgets. A promising intervention is through restoring tidal exchange to impounded coastal wetlands for reduced methane (CH 4) emissions. We monitored an impounded wetland's GHG flux (CO 2 and CH 4) prior to a...
Article
Research into the microbiomes of natural environments is changing the way ecologists and evolutionary biologists view the importance of microorganisms in ecosystem function. This is particularly relevant in ocean environments, where microorganisms constitute the majority of biomass and control most of the major biogeochemical cycles, including thos...
Article
Full-text available
Detection and quantification of greenhouse-gas emissions is important for both compliance and environment conservation. However, despite several decades of active research, it remains predominantly an open problem, largely due to model errors and assumptions that appear at each stage of the inversion processing chain. In 2015, a controlled-release...
Article
The study of ancient DNA (aDNA) from sediments (sedaDNA) offers great potential for paleoclimate interpretation, and has recently been applied as a tool to characterise past marine life and environments from deep ocean sediments over geological timescales. Using sedaDNA, palaeo-communities have been detected, including prokaryotes and eukaryotes th...
Article
Full-text available
Detection and quantification of greenhouse-gas emissions is important for both compliance and environment conservation. However, despite several decades of active research, it remains predominantly an open problem, largely due to model errors and misspecifications that appear at each stage of the inversion processing chain. In 2015, a controlled-re...
Data
A methane (CH4) and carbon dioxide (CO2) release experiment was held from April – June 2015 at the Ginninderra Controlled Release Facility in Canberra, Australia. The experiment provided an opportunity to compare different emission quantification techniques against a simulated CH4 and CO2 point source release, where the actual release rates were un...
Conference Paper
A two month long methane and carbon dioxide blind release experiment was held in Canberra, Australia, during 2015. The primary objective of the experiment was to conduct a simultaneous comparison of different atmospheric emissions quantification techniques against a point source release. Seven quantification techniques were assessed during the tria...
Article
One consequence of High Arctic permafrost thawing is the formation of small ponds, which release greenhouse gases (GHG) from stored carbon through microbial activity. Under a climate with higher summer air temperatures and longer ice-free seasons, sediments of shallow ponds are likely to become warmer, which could influence enzyme kinetics or selec...
Chapter
This chapter presents an overview of the fate, transport, and behavior of nanomaterials (NMs) in the environment, explaining that most releases of manufactured NMs or engineered NMs originate from point or nonpoint sources. A few well-known properties are likely to be helpful in predicting the transport and separation among environmental media base...
Conference Paper
The expansion of permafrost thaw ponds, a widespread feature of Canadian arctic sedimentary basins, is accelerating due to climate change. Permafrost soils store half of the global below ground organic carbon stock, which is now being mobilized as peat soils thaw and erode. Thaw ponds are large emitters of methane and carbon dioxide. Our studies of...

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