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North Dakota Water Resources Research Institute
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Title:
Survey of the Phytoplankton
Communities Involved in Oxygen Supersaturation Under the Ice in Shallow North
Dakota Lakes Focus Categories: Water Quality, Ecology. Wetlands Project
No.
ND94-05 Principal
Investigator
Completion Report Fawley,
Marvin W. and Karen A. Phillips, 1997, Phytoplankton Communities Associated with
Elevated Oxygen Levels Under the Ice in Shallow North Dakota Lakes, Rept. No.
ND94-05, North Dakota Water Resources Research Institute, North Dakota State
University, Fargo, North Dakota, 6 pages. Other
Publications Phillips,
Karen A., 1998, Phytoplankton Community Structure under Ice in Shallow North
Dakota Lakes, “Ph.D. Dissertation,” Department of Botany/Biology, North
Dakota State University, Fargo, North Dakota, 96 pages. Phillips,
Karen A. and Marvin W. Fawley, 1996, Winter phytoplankton Assemblages in North
Dakota Lakes, in Proceedings Fifth North Dakota Water Quality Symposium, B.D.
Seelig, ed., March,
1996, NDSU Extension Service, pages 17-21. Significant
Findings It
was found that blooms of several organisms, particularly a dinoflagellate and
several species of cryptomonads, are associated with high DO levels that occur
in shallow North Dakota lakes in late February and early March. However, these
blooms do not occur every year. It is likely that the bloom is initiated by the
germination of cysts of the dinoflagellate found in the sediment. Many
phytoplankton are present during the winter, and the winter season is an active
period for phytoplankton despite the short days and low light levels. The
results challenge the accepted ideas of phytoplankton seasonal dynamics, which
hold that very little phytoplankton growth occurs during winter.An unexpected
diversity of very small green algae was found in the Arrowwood lakes.
Traditional keys essentially useless for the identification of these organisms,
and new methods were developed. To date, nineteen different “species” have
been identified among the isolates, only one of which matches any named
organism. These results show that the diversity of these organisms is much
higher than was previously suspected. The methods employed for identification
also will allow the ecology and distribution of these organisms to be studied
for the first time. |
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