Geoscience Reference
In-Depth Information
Chemically, the lakes range from some of the freshest lakes in the world to hypersaline
lakes, which do not freeze over, even in winter when their temperature can drop below
−
C.
Epishelf lakes such as Kakapon Bay in the Bunger Hills can exhibit full marine
conditions together with a marine
10
°
fl
flora and fauna including seal populations. Depending
on the degree of chemical in
fl
uence from the sea, versus interior climate regimes, lakes are
often classi
ed as coastal maritime lakes or coastal continental lakes. The nutrient status
of Antarctic lakes is typically oligotrophic, with eutrophy usually restricted to those,
which are directly in
uenced by visiting marine mammals, birds or people. Table
6.1
shows characteristics of the water quality in several epiglacial
fl
lakes in the western
Dronning Maud Land.
Epiglacial lakes are an important habitat of life in the polar world (Kaup 1994). They
contain phytoplankton, few zooplankton but no
fish. Mosses are the highest forms of
aquatic plant life on the continent, while higher plants are present in lakes on the peri-
antarctic and sub-Antarctic islands (e.g., in South Georgia). However, the bulk of the
biomass and primary productivity is benthic, consisting of cyanobacteria, diatoms and
green algae, often in luxuriant mats several meters thick (Vincent 2000; Ellis-Evans
1996). The mats can be grazed by communities of rotifers, ciliates and crustacea, though
Table 6.1
Basic geochemistry of epiglacial lakes in austral summer 2010
-
2011 based on in situ
sounding with YSI handheld multiparameter instrument (Keskitalo et al. 2013)
Date
Site
Cond (25
°
C)
Diss O
2
(mg l
−
1
)
pH
Tot-N
(mg m
−
3
)
Tot-P
(mg m
−
3
)
(S cm
−
1
)
Dec 22
Top pond
11.5
12.11
7.88
149
3
Dec 30
59.5
10.84
6.91
x
x
Jan 23
45.8
10.16
6.14
x
x
Jan 10
Top pond 2
249.0
8.48
8.19
82
4
Jan 23
253.8
9.73
8.42
85
3
Dec 29
Ring pond
26.3
12.15
9.64
x
x
Jan 08
27.2
12.50
7.6
180
15
Jan 17
35.3
11.72
8.54
149
3
Dec 29
Velodrome
162.8
10.54
7.83
x
x
Jan 08
Centre
93.0
11.94
7.8
717
4
Jan 17
Centre
82.6
12.12
7.70
205
2
Jan 08
Shore
163.7
19.62
10.82
253
15
Jan 17
Shore
93.1
15.05
9.94
800
34
Jan 13 Fossilryggen
Centre 63.6 12.37 9.78 220 3
Shore 61.0 12.68 8.96 284 3
Top pond and Top pond 2 are located on top of Basen nunatak, Ring pond and Velodrome pond are
located at the foot of Basen, and Fossilryggen on the top of Fossilryggen nunatak
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