DIVING PROTOCOLS TO MINIMIZE
ENVIRONMENTAL IMPACT IN
MCMURDO DRY VALLEY LAKES

1.0 SCOPE AND APPLICATION:

1.1 Antarctic ice-covered lakes in the McMurdo Dry Valleys region contain a fragile benthic community and a highly stratified water column with respect to oxygen, temperature and salinity content. Research diving is a potential disturbance to Dry Valley's lakes due to:
  • Introduction of gases to the water column,
  • Introduction of contaminants to the lake,
  • Destabilization of the water column due to: a) dive-associated heat transfer, b) physical mixing due to swimming action of the diver itself and c) mixing due to movement of exhaled bubbles,
  • Disturbance by the swimming action of divers to fragile benthic communities

These potential impacts have been shown to be at the most minor or transitory through theoretical model results and actual field study (Kepner, et. al.), assuming diving protocols in the Dry Valleys include measures to ensure responsible and environmentally sound diving practices and that these protocols are followed.

2.0 GENERAL DIVING PROTOCOL FOR DRY VALLEYS LAKES

The following procedures, which may be already in place in Dry Valley diving protocols and safety procedures, will be used to ensure minimal impact during the 1998-1999 season. Additional restrictions for the Lake Vanda diving program are provided in Section 3.0.

2.1 Diving materials such as ropes, metallic, rubber and plastic fittings will be clean and dry prior to use and, wherever possible, dedicated for use at a specific lake only.

2.2 Damage due to operator contact of dive lines with the lakebed will be avoided by using communications tethers that are positively buoyant. A surface supply dive umbilical (positively buoyant) is also recommended to ensure that only local (Dry Valley) gases are introduced into the water column.

2.3 Restricting Antarctic dive personnel to those highly experienced in diving under ice and in delicate environments will ensure proper line control and avoid disturbing the lakebed by the swimming motion of the diver. Divers should use buoyancy to rise far off the bottom before finning.

2.4 Observations by dive personnel concerning environmental impact, pertaining to the items in 1.0 or other, will be collected during diving events and compiled in an end-of-season report to NSF as outlined in 4.0.

3.0 PROTOCOLS SPECIFIC TO LAKE VANDA DIVING PROGRAM

3.1 Diving protocols and safety procedures will be the same as those employed in previous seasons in which LTER researchers have been diving in the Dry Valleys lakes.

3.2 Diving activities will be limited to depths of less than 23 m, the upper boundary of the density gradient which separates the upper and lower convecting cells in Lake Vanda.

3.2 Sampling will be at a range of depths from below the ice to 23 m.

4.0 END OF SEASON REPORT

4.1 Researchers will provide to the NSF Environmental Officer an End of Season Report detailing their observations concerning the environmental effects as a result of their diving operations. The report will include, at a minimum, the following:
  • Number, duration, and locations of dives conducted during the season,

  • Personnel performing the dives,

  • Observations of environmental effects, and

  • Recommendations for future diving events.

5.0 REFERENCES

5.1 Lake Vanda Diving Programme, 1998/99; environmental impact, safety and scientific justification, unpublished.

5.2 Kepner, R., A Kortyna, R. Wharton, P. Doran, D. Anderson, E. Roberts, "Effects of Research Diving on a Stratified Antarctic Lake", in publication.

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