Glossary of Alaska Natural History Terms:
References listed at the bottom |
| A B C
D E
F G
H I
K L
M N
O P
Q R
S T
U V
W X
Y Z |
A
Active layer. A seasonally
thawed surface layer of soil in arctic or alpine regions that
lies above permanently frozen ground and is between a few centimeters
and about 3 meters thick. |
| Afforestation.
The establishment of forest by natural succession or by the planting
of trees on land where they did not grow formerly. Afforestation.
The establishment of forest by natural succession or by the planting
of trees on land where they did not grow formerly. |
| Alcids.
Any of the Alcidae family (Order Charadriiformes) of marine
birds having a stout bill, short wings and tail, webbed feet,
a large head and heavy body, and thick, compact plumage. Confined
to the northern parts of the Northern Hemisphere, alcids include
auks, guillemots, murres, and puffins. Any of the Alcidae family
(Order Charadriiformes) of marine birds having a stout bill,
short wings and tail, webbed feet, a large head and heavy body,
and thick, compact plumage. Confined to the northern parts of
the Northern Hemisphere, alcids include auks, guillemots, murres,
and puffins. |
| Alevin.
A young fish, particularly a young salmon that is still attached
to the yolk sac. A young fish, particularly a young salmon that
is still attached to the yolk sac. |
| Algae.
The common name for the relatively simple type of unicellular
or multicellular plant which is never differentiated into root,
stem, and leaves, contains chlorophyll a as its photosynthetic
pigment, has no true vascular system, and has no sterile layer
of cells surrounding its reproductive organs. Found in most
habitats on Earth, though the majority occur in freshwater or
marine environments. The common name for the relatively simple
type of unicellular or multicellular plant which is never differentiated
into root, stem, and leaves, contains chlorophyll a as its photosynthetic
pigment, has no true vascular system, and has no sterile layer
of cells surrounding its reproductive organs. Found in most
habitats on Earth, though the majority occur in freshwater or
marine environments. |
| Alluvial.
Of or relating to river and stream deposits. Of or relating
to river and stream deposits. |
| Alluvial
soil. Soil formed in material deposited by the action of
running water, such as a floodplain or delta. soil. Soil formed
in material deposited by the action of running water, such as
a floodplain or delta. |
| Alpine
tundra. A treeless region above the tree line of high mountains,
characterized by cold winters and short, cool summers and having
permafrost below a surface layer that may melt in summer. tundra.
A treeless region above the tree line of high mountains, characterized
by cold winters and short, cool summers and having permafrost
below a surface layer that may melt in summer. |
| Amphidromous.
Referring to the migratory behavior of fishes moving from fresh
water to the sea and vice versa, not for breeding purposes but
occurring regularly at some stage of the life cycle (such as feeding
or overwintering).Amphidromous. Referring to the migratory behavior
of fishes moving from fresh water to the sea and vice versa, not
for breeding purposes but occurring regularly at some stage of
the life cycle (such as feeding or overwintering). |
| Anadromous.
Referring to the life cycle of fishes, such as salmon, in which
adults travel upriver from the sea to breed, usually returning
to the area where they were born. Referring to the life cycle
of fishes, such as salmon, in which adults travel upriver from
the sea to breed, usually returning to the area where they were
born. |
| Back
to top
B |
| Boreal
forest. The circumpolar, sub arctic forest of high northern
latitudes that is dominated by conifers. The boreal forest stretches
across North America, Europe, and northern Asia (regions characterized
by short summers and long, cold winters). It is found south
of the tundra in the Northern Hemisphere and often contains
peaty or swampy areas. Boreal forest. The circumpolar, sub arctic
forest of high northern latitudes that is dominated by conifers.
The boreal forest stretches across North America, Europe, and
northern Asia (regions characterized by short summers and long,
cold winters). It is found south of the tundra in the Northern
Hemisphere and often contains peaty or swampy areas. |
| Brackish.
Water that is saline but not as salty as seawater. Water that
is saline but not as salt |
