Concept information
Preferred term
MERSAM
Definition
- Short Title: MERSAM Proposal URL: http://classic.ipy.org/development/eoi/proposal-details.php?id=439 Mercury (Hg) in the arctic has received considerable attention since several investigations have shown an increase in Hg concentration in various biota samples, including marine mammal tissues and seabird eggs which were mainly enriched in methylmercury (MeHg). These relatively high concentrations of Hg represent an important health issue for the rural indigenous native arctic communities consuming these products. The distribution of Hg in the top level of the arctic food web is well mirrored by the concentration of Hg in seabird eggs, where spatial differences exist between the Alaskan and Canadian arctic, with a marked Hg increase observed since 1975 in the Canadian arctic and distinct Hg signatures that are measured between seabird colonies residing in the Gulf of Alaska and Bering Sea, signatures that are subject to an apparent year-to-year variability and species specific effects. These spatial and temporal patterns as well as the levels of Hg in the food web prompt several fundamental questions on the nature of the sources of Hg that need to be answered through research, namely relative anthropogenic/natural contributions of Hg throughout and across ecosystems, the processes driving these patterns (i.e., sources, atmospheric transport and deposition, ocean currents, and evolution of the food web structure), their linkages and their respective contributions over time. All these processes need to be assessed on a spatial scale (considering arctic and sub-arctic regions) as well as on a temporal scale to evaluate the amplitude of these factors over time. In the absence of extensive Hg atmospheric monitoring stations in Alaska and also considering the variability and scarcity of data on Hg and MeHg levels in snow and seawater in Alaska, no direct temporal and spatial approaches can be conducted. In this proposal we utilize an indirect approach consisting of: (1) Tracking the sources of Hg and assessing regional differences by analyzing seabird eggs and feathers collected on a regular basis at several locations in the North American arctic and sub-arctic regions. These samples are archived at the Marine Environmental Specimen Bank (Charleston, SC, USA) administrated by the National Institute of Standards and Technology (NIST), at the Canadian Wildlife Service Specimen Bank (Ottawa, ON CANADA) and are housed in various collections curated by University of Alaska Fairbanks (UAF) Museum of the North and independent UAF researchers. (2) Assessing the long-term temporal trend of Hg in the top marine food web using time series of collections of seabird eggs and feathers. The spatial and retrospective approaches for monitoring Hg and MeHg in the samples will be coupled with several other sources of information including food web tracers (C and N stable isotopes ratios), as well as tracers of atmospheric transport/sources such as lead isotope ratio patterns in seabird eggs and feathers, and organic contaminant patterns in seabird eggs. Alone, all these data are valuable, but the power exists to collectively investigate the spatial/temporal relationship existing between the nature of Hg sources, their geographical extent and their accumulation/transfer in the arctic/sub-arctic foodweb. (en)
Broader concept
- M - O (en)
URI
https://gcmd.earthdata.nasa.gov/kms/concept/da6f7ff1-84cf-4a1f-9b64-538518086d96
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