Geoscience Reference
In-Depth Information
Figure 16-43. Estonian postage stamps depicting wetland habitats. Matsula Looduskaitseala (nature protection area;
later designated as a national park), an estuary system on the western mainland coast. Tolkuse raba, a bog in the
southwestern mainland. Lakes Peipsi-Pihkva on the eastern margin, which together are Europe's fourth largest lake.
Original stamps printed in multiple colors.
Figure 16-44. Satellite image of Lake Peipsi and surroundings, Estonia and Russia. Endla, Alam Pedja, and
Emajõgi-Piirissaar are Ramsar wetlands of international importance. Landsat ETM
+
band 5 (mid-infrared). Date of
acquisition 10 July 1999. Image from NASA; processing by J.S. Aber.
• Ombrotrophic - Raised bogs that are fed
entirely by atmospheric precipitation. Bogs
may include pines ( Pinus sylvestris ) or
be treeless, depending on the amount of
nitrogen and phosphorus available for tree
growth. Sphagnum fuscum is the principal
peat-forming plant along with several other
Sphagnum species. Rate of peat accumula-
tion averages 0.5 to 1.0 mm per year, depend-
ing mainly on precipitation. Bogs amount to
about one-third of Estonian mires.
to uplift, while the southern portion of the
country has subsided. This phenomenon con-
tinues today and is illustrated by Lake Peipsi
(Fig. 16-44); the northern end is rising at 0.2-
0.4 mm per year, while the southern part is
sinking at 0.8 mm per year (Hang and Miidel
1999). Thus, the lake is transgressing toward
the south, which has led to extensive shore
erosion, submergence of medieval villages and
churches, and paludii cation of wetlands around
the southern margin. For example, the island of
Piirissaar, a Ramsar site near the southern end
of Lake Peipsi, decreased from
20 km 2 area in
1796 to only 7.5 km 2 today (Hang and Miidel
Since the last ice sheet retreated, isostatic
crustal adjustment has caused northern Estonia
Search WWH ::




Custom Search