In an effort to better understand processes that provide the fuel for primary-production in the iron-limited waters offshore and down-current of the Western Antarctic Peninsula (WAP), the National Science Foundation Office of Polar Programs awarded a 3-year, $530,000 grant to a research team led by me, Dr. Reide Corbett, in collaboration with Dr. Kim Null (ECU Postdoctoral Scholar) and Dr. Berry Lyons (OSU Byrd Polar Research Center). This study will quantify the rate of submarine groundwater discharge, or the exchange of groundwater between land and sea, and associated flux of nutrients and iron to coastal waters of the WAP.
Gill, from ‘Finding Nemo,’ summed it up best, “All drains lead to the sea.”
Similarly, in our case, groundwater in coastal aquifers flow down slope and ultimately discharge to the coastal ocean, a process we refer to as submarine groundwater discharge. This process is very common and the water discharged is comprised of terrestrial freshwater mixed with seawater that has infiltrated coastal aquifers. What’s important is that this water often has high concentrations of nutrients and other potential contaminants. Our study in the Antarctic is focused on quantifying the rate of discharge and evaluating whether it might contribute to the iron concentration in the Southern Ocean.
The waters offshore of the WAP, and many other locations throughout the Southern Ocean, are high nutrient-low chlorophyll (HNLC) environments that have been shown to be iron and light limited. Therefore, if you add iron to the waters, primary production increases, linking the ecosystem and this project to the global carbon budget. Recent research has shown increased primary production through the delivery of iron-rich, continentally-derived sediments from wind and icebergs.
We hypothesize that the exchange of groundwater between land and sea will contribute a significant proportion of iron to coastal waters, and that mixing across the continental shelf will deliver this important nutrient to offshore waters.
The Antarctic Peninsula is experiencing significant glacier melting and sea ice retreat associated with a warming climate. Changes in the ecosystem, from primary production to the penguins, have been attributed to the volume of freshwater input to the near shore environments. We are attempting to quantify a source of freshwater and nutrients that have yet to be considered in this part of the world.
That alone is pretty exciting.
The scientific team includes faculty and students from ECU, the UNC Coastal Studies Institute and Coastal Carolina University. We will leave the United States on December 6 to board the RV Lawrence M Gould (will refer to it as the LMG; see photo below) in Punta Arenas, Chile. On December 10th , the LMG will leave port and start heading to Palmer Station. We will cross Drake Passage, known for its extremely rough seas, heading ultimately for Palmer Station located on Anvers Island near the Antarctic Peninsula (64° 46’S, 64° 03’W). Once we arrive in the area, we will spend ~5 days sampling ocean waters on the continental shelf adjacent to Palmer Station. The se samples will provide information on the rate of cross-shelf mixing…providing us an estimate of how quickly freshwater entering the coastal zone can move into open ocean waters. After this offshore work, four of our team will leave the ship, transferring to Palmer Station for the next 6 weeks. While on station, we will collect nearshore samples using a 16-foot Zodiac. These samples will be analyzed for different groundwater traces, nutrients, and iron (see future blog posts for additional information on sampling and methods). Our scientific crew will return to the US around February 10th…quite the journey!
We are really looking forward to this exciting new program, from a scientific perspective as well as the shear adventure that will certainly unfold in the coming weeks. I hope you will come back often and follow along as we discover a new area of the world (at least for us) and hopefully uncover some new scientific understanding of groundwater processes in the coastal Antarctic.
I have included two images. The first shows a Google Maps rendition of our planned cruise track (red line) and study area (blue box). The other photo is of the LMG docked at Palmer Station (photo from http://www.nsf.gov/od/opp/support/gould.jsp). Use the included links to find more information on Palmer Station, including a live webcam (http://www.usap.gov/videoclipsandmaps/palwebcam.cfm), and the LMG (http://www.usap.gov/usapgov/vesselScienceAndOperations/index.cfm?m=4 ), including its current location (http://www.sailwx.info/shiptrack/shipposition.phtml?call=WCX7445).
