Variability of transparent organic particles in Arctic floodplain lakes

Jan 15, 2013

In the North American Arctic the Mackenzie River courses into the Beaufort Sea, the outlet of a watershed that drains a vast swath of the western Canadian landscape. At the river's mouth, the Mackenzie Delta is a broad floodplain peppered with roughly 45,000 lakes carved into the permafrost. Depending on their connectivity to the river, these floodplain lakes have different mixtures of organic compounds, and such differences affect carbon cycling and sediment processes in the lakes.

Among the prevalent in these Arctic lakes are transparent exopolymer particles (TEP), a gel-like substance formed by the spontaneous aggregation of sticky chains of that are secreted by algae, bacteria, and other organisms. Previous research found that aggregates of TEP form habitats for and reaction surfaces for aqueous chemicals and can help promote sedimentation. In the ocean, TEP is a key component of ocean "snow." The role and variability of TEP in Arctic lakes and other inland waters, however, has been relatively unstudied.

Collecting weekly water samples from three lakes over a 2-month span in 2006, Chateauvert et al. measured how the concentrations of TEP and other organic compounds varied following the annual flooding of the . The authors find that the concentration of TEP varied by up to two orders of magnitude over the course of the study period, peaking immediately following the June flood and declining steadily afterward. They also find that the lake best connected to the river had the highest TEP concentrations. These findings ran directly counter to the authors' initial hypothesis of how TEP concentrations should evolve in the lakes. The authors find that changes in the concentration of chromophoric dissolved organic matter—a form of organic material derived almost exclusively from river water in the region—could account for more than half of the measured TEP variability.

Explore further: NASA HS3 mission Global Hawk's bullseye in Hurricane Edouard

More information: Abundance and patterns of transparent exopolymer particles (TEP) in Arctic floodplain lakes of the Mackenzie River Delta, Journal of Geophysical Research–Biogeosciences, doi:10.1029/2012JG002132 , 2012

add to favorites email to friend print save as pdf

Related Stories

Hormone may help predict tubal ectopic pregnancy

May 03, 2012

Tubal ectopic pregnancy (TEP) is currently the leading cause of pregnancy-related deaths during the first trimester and a recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & ...

Dams impact carbon dynamics in U.S. rivers

Aug 08, 2012

Dissolved organic carbon (DOC)—which leaches into freshwater systems from plants, soils, and sediments, and from other detritus present in the water itself—is the major food supplement for microorganisms and plays ...

Organic carbon suggests Swedish lakes were less acidified

Aug 01, 2011

During the 1970s and 1980s, researchers and policymakers became increasingly worried about multiple consequences of acidic emissions of sulfur dioxide and nitrogen oxides from the stacks of power stations, and eventually ...

Recommended for you

NASA image: Fires in the southern United States

18 hours ago

In this image taken by the Aqua satellite of the southern United States actively burning areas as detected by MODIS's thermal bands are outlined in red. Each red hot spot is an area where the thermal detectors ...

Software models ocean currents for oil and gas search

19 hours ago

A study involving the use of streamline visualisation has found the technology can help guide electromagnetic transmitter and receiver placements, thereby aiding the search for oil and gas on the seafloor.

User comments : 0