AEO {Arctic Environmental Observatory}

The water sampling efforts at Little Diomede are one of three components of the Bering Strait Environmental Observatory, with marine mammal and shipboard benthic sampling the two other current components.

The objective of the water sampling effort is to establish an onshore seawater observatory at Diomede Village, Alaska, in the center of Bering Strait. The strategic location of this observatory on Little Diomede Island will permit rapid, flexible collection of chemical, biological, and physical data on the transport of nutrient- and organic-rich waters of north Pacific origin into the Arctic Ocean through this narrow strait. During the summer of 2000, and 2001, and in the winter of 2003, we installed water sampling equipment to continuously measure Bering Strait water for autonomous determinations of salinity, temperature, nitrate, nitrite, phosphate, and fluorometric proxies of chlorophyll a. We also have collected hourly-to-daily water column samples of silicate, ammonia, total fixed nitrogen and phosphorus, and d18O. Lou Codispoti and Lee Cooper share responsibility for this portion of the project. These data have been largely edited for data quality assurance and are available upon request to interested scientific users.

Nutrient Survey Data. One of the issues that we have been resolving is whether water sampled at Little Diomede Island from our shallow water intake is representative of water as a whole flowing through the Bering Strait, or whether there are "island" effects that reflect contributions from the 3 million birds that nest on the island in the summer or human impacts from the 150 year-round residents. For seawater as a whole, we have used oxygen isotope analyses, which indicates that the water sampled at the island is almost identical (d18O = -1.1) to the Bering Sea signal that is present in the upper halocline of the Arctic Ocean.  Nutrient analyses can help address the question of local inputs.  We have now completed surveys of nutrients in surface and bottom waters in the vicinity of the island both in the winter and summer.  The results indicate that "island" effects are very local (within 100-200 m) to the island, and we can expect to sample representative water masses as they pass the island through Bering Strait. Nutrient concentrations do vary in response to wind events and water mass boundaries, but anomalous concentrations appear to be limited and inshore of our proposed new undersea intake system.  We have prepared .pdf files of a number of these surveys at the following ftp site, which are available for anonymous downloading:  Nutrient Surveys


Contact us for a reprint of  "The Potential for Using Little Diomede Island as a Platform for Observing Oceanographic Conditions in Bering Strait," by L.W. Cooper, L.A. Codispoti, V. Kelly, G.G. Sheffield and J.M. Grebmeier, Arctic 59(2):129-141, published in June 2006.

Our capabilities to pump water onshore for analysis on a 24/7 year-round basis have been limited by storm and ice damage. Photos of a typical fall storm in October 2004. These challenging issues remain, including development of reliable mechanisms for bringing water onshore on a continuous basis year-round, in a remote community that is strongly impacted by storms and seasonal sea ice. Data transmission from the island via the internet has also been limited although we have contributed to some recent satellite-based improvements.. With support from the National Science Foundation, and its arctic logistics contractor, VECO Polar Resources, Inc., a geotechnical study was conducted in March-April, 2002, followed by a feasibility study for a more permanent water inlet that will be drilled beneath the shore, and be less vulnerable to storm and ice damage. A copy of the feasibility study, prepared by Peratrovich, Nottingham and Drage, of Anchorage, can be downloaded here as a .pdf file. We have proposed to the National Science Foundation to follow up this feasibility study with an engineering effort to directionally drill a more permanent water intake system at Diomede.  Another element proposed for the water intake conduit will be fiber optics and electrical utilities to support additional instrumentation at the point of the water intake. Two examples of the type of directional drilling that are feasible at Diomede were recently undertaken by U.S. Navy-supported teams at Ascension Island in the south Atlantic and San Nicholas Island, off the coast of southern California.  A .pdf file including photographs of the Ascension Island drilling operation, and based upon a presentation made at the 2003 Marine Science Technology Conference (Oceans ’03) in San Diego can be downloaded here. Additional photos of the Ascension Island drilling operation, courtesy of Mr. Stan Black, PE, of Ventura , California .

Geotechnical drilling (March 2002) to characterize sub-sea rock. This information will be used to plan a proposed directional drilling operation to develop a more permanent water intake system.

 

Water pumping through the ice in April 2003. Photo by Dave Brown

Nearly continuous water column data collected from some of our interim efforts have now been largely edited and are available upon request. Each file includes approximately 50,000 lines of data, including salinity, temperature, inorganic nutrients, oxygen-18/16 ratios over different time increments (every 30 seconds to once daily). These data are being combined with other Arctic data for scientific use and eventual publication. For example, a copy of a presentation incorporating some of these data was made at the February 2004 Ocean Research Conference in Honolulu.

 

 

Data sample from spring of 2003. A modified version of this figure has been published in our June 2006 paper, published in the professional journal Arctic.

Ultimately, our vision of the water sampling effort is a real-time data stream accessible via the Internet from anywhere world-wide. In addition we will have a web-searchable data archive such as is outlined below with quality-assured data available to the scientific community and interested local users in the Bering Strait region. Your comments and suggestions are welcome and can be provided to Lee Cooper (lcooper1@utk.edu).

 

Data Archives (THIS AREA IS UNDER CONSTRUCTION)

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[arctic.bio.utk.edu]