Kobuk River Totally Explained

Everything about Kobuk River totally explained

The Kobuk River is approximately long, located in the Arctic region of northwestern Alaska in the United States. Draining a basin with an area of 12,300 square miles (31850 sq km), the Kobuk River is among the largest rivers in northwest Alaska with widths of up to 1500 feet (460 m) and flow at a speed of 3-5 miles per hour (5-8 km per hour) in its lower and middle reaches . The Kobuk’s water is clear and carves meander scrolls, oxbow bends, and sloughs along its middle and lower course
The Kobuk's Inuit name means "big river". It was first transcribed by John Simpson in 1850 as "Kowuk." Explored by Lt. G. M. Stoney, USN, in 1883-1886, who wrote the name "Ku-buck," but proposed that it be called "Putnam" in honor of Master Charles Flint Putnam, USN, officer of the Rodgers, who was carried to sea on the ice and lost in 1880. Lt. J. C. Cantwell, USRCS, also explored the river in 1884 and 1885 and spelled the name "Koowak" on his map and "Kowak" in his text. Ivan Petroff spelled the river name "Kooak" in 1880, and W. H. Dall spelled it "Kowk" in 1870. Lt. H. T. Allen, USA, obtained the Koyukan Indian name in 1885 which he spelled "Holooatna" and "Holoatna."
Native peoples have hunted, fished, and lived along the Kobuk for at least 12,500 years A portion of the vast Western Arctic Caribou Herd utilize the Kobuk river valley as winter range.

Climate

The Kobuk River Basin is located just north of the Arctic Circle and has a continental climate. The summers are short and warm, while winters are long and cold. The mean annual temperature in the middle and upper portions of the Kobuk Valley is -6°C, and the mean temperature in July is 15°C . An average of 21 inches (53 cm) of precipitation falls in the basin. However, actual precipitation can range from 15-40 inches (40-100 cm) with greater amounts falling in the upper reaches of the river basin . Records of air-temperature from 1961-90 logged at the latitudes of the Kobuk River, show a warming trend of about 1.4°F (0.78°C) per decade . Much of the increased precipitation has fallen as rain, mostly in winter months .

As a specific example, climate change will cause widespread thawing of permafrost in the discontinuous zone and significant changes in the continuous zone. Thawing permafrost can lead to a landscape of irregular depressions (thermokarst) due to subsiding soils. This can alter drainage patterns and even change the course of streams; whereas other areas could become swamplike. In addition, slope stability will decrease and permafrost degradation could lead to erosion of river banks resulting in an increase in sediment transport by the rivers . These physical changes will impact nutrient cycling and biological processes within the basin as well.

Geology and Soils

[[Image:Permafrost regions along kobuk.jpg|center| After the first stage of aggradation and sediment transport, the Kobuk began a new phase of erosion and landform development. The river exhausted its supply of easily erodible sediment upstream, thus decreasing its sediment load and increasing its downstream load carrying capacity. With more carrying capacity downstream, the river began to incise into the alluvial fan it previously created, moving sediment stored for a long time on its original floodplains to newer floodplains further downstream. In moister climates, the river has more water, and thus more power, and cuts down through a sandy bed. In times of drier climate, wind dominates and blows a lot of sediment into a weaker fluvial system, leading to aggradation and floodplain re-distribution. Currently, the Kobuk River in its middle and lower reaches is an anastomizing stream, with several braided channels in places, wide migrating meander bends, and oxbow lakes. It is controlled by yearly cycles of freeze and thaw, much like its surrounding landscape. For six months of the year, the river is largely still, frozen on top by a thick layer of ice. . Within the Kobuk Valley National Park, are the Kallarichuk, Salmon, Tutuksuk, Kaliguricheark, Hunt, and Adillik rivers. All of their headwaters are in the Baird Mountains . Other surface water features within the basin include Lake Selby, Nutuvukti Lake, and Norutak Lake The Kobuk River dipteran community are largely composed of Chironomidae (non-biting midges), Ceratopogonidae (biting midges), and to a lesser extent, Simuliidae (black flies) and Empididae (dagger flies). Primary productivity on the Kobuk River, similar to many high Arctic rivers, is largely composed of fine particulate organic matter (from the direct leaching of peat) and the dipterans (especially the chironomid midges) seem particularly suited to capitalize on this important carbon source due to their functional feeding adaptations. Specifically, these types of species acquire the majority of their food resources through direct filtering and collection of minute food particles suspended in the water column, although some are predators. Due to minimal coarse particulate organic matter and other sources and nutrients, it appears that the filter feeding/collector and highly tolerant dipterans are uniquely situated to dominate the aquatic invertebrate community of the Kobuk River. In addition, these families and others show several ecological and physiological adaptations allowing them to persist under the harsh Arctic environmental conditions. Those species able to survive through the Arctic winter on the Kobuk River are primarily univoltine, exhibit a long life cycle which may exceed an entire year, experience periods of dormancy, and may use particular advantageous physiological adaptations to endure the cold winter months., either through larval dehydration or by creating specific proteins which protect the internal cavity of the species.

Fish

The Kobuk River drainage contains at least 18 species of fish along the roughly 450 km of main stem and thousands of streams, lakes, ponds and sloughs. All the species are native and none are listed as threatened or endangered. Fishing is an important part of the native culture in the Kobuk River and fish often constitute the main part of the diet (for example ). Fish comprises more than half of the subsistence harvest in many households on the Kobuk River
    Walker Lake is a large glacial lake located close to the headwaters of the Kobuk River approximately 400 km upstream from Hotlam Inlet. The lake contains a variety of fish species: whitefishes, chars, northern pike, longonse sucker, burbot, slimy sculpin and ninespine stickleblack, among others There are many other lakes in the Kobuk River drainage that, in some cases, contain similar assemblages and provide essential overwintering and feeding areas to the fish of the Kobuk River. The river supports many migratory populations of whitefish, and to a lesser degree chum salmon and, Dolly Varden, whose abundances are seasonal. Some species are permanently present in the main stem, such as Alaska blackfish, which is well adapted to the severe winter conditions of the arctic Kobuk River. The lower floodplains of the Kobuk River, especially close to the Kobuk River delta, contain many shallow lakes and sloughs that create a high diversity of habitats normally used for feeding and overwintering.
    The order salmoniformes has the highest richness among the Kobuk species, which is typical of arctic freshwater ecosystems. The families present are Salmonidae (with three subfamilies: Coregoninae, Salmoninae and Thymallinae), Esocidae, Lotidae, Dalliidae, Catostomidae, Cottidae and Gasterosteidae (Table 1). The subfamilies Coregoninae and Salmoninae are the most significant in the Kobuk River with at least six and five species respectively. All other families have only one species represented. Table 1. Families and species of fish represented in the Kobuk River.
    In the spring before the ice breaks up, the sheefish start the slow upstream migration in the Kobuk River; The diet varies according to size, age and season. The young start feeding on plankton, but soon prey upon insect larvae and zooplankton. Important in the adult diet are isopods, Mysis and other whitefishes, char, smelt, blackfish, suckers, burbot, sticklebacks and sculpins which are abundant in the Kobuk River drainage.
    Broad whitefish (Coregonus nasus) are called the Kobuk River fish because they're more abundant in the Kobuk River than in other rivers of the region, but not in such large numbers as some of its relatives. They are the largest whitefish in the Kobuk River after sheefish, have a high fat content, and are an important species for the subsistence of the native people This species has a variety of ecological forms in the Kobuk River system, and are seasonally present in most of the available habitats (Table 2) Chum have been observed as far inland as Walker Lake
    Lake trout (Salvelinus namaycush) are the largest freshwater fish in Alaska. /> Lake trout are char with a limited distribution to a few deeper headwater lakes in the upper Kobuk River, such as Walker Lake and Selby Lake. and have been observed while spawning in several Kobuk River tributaries. They are freshwater residents in the main Kobuk River, tributaries and lakes, and migrate among habitats for spawning in the spring, feeding during the summer and overwintering. They are even able to complete their life cycle in short river sections or in a lake without the need for migration. which inhabit probably the deepest waters of the Kobuk River system. They have been reported in the main stem, They spawn under the ice during the winter and mill together forming a ball while spawning. Spawning occurs in lakes and rivers; sedentary fish don't undertake important spawning or feeding migrations. They move to shallow waters to spawn on sand, gravel or cobble grounds. Alaska blackfish probably occur in most habitats of the Kobuk River system due to their ability to thrive in any conditions. They are sluggish bottom feeders that may be abundant in the tundra and floodplain lakes and sloughs of the main stem. They can survive in stagnant tundra pools, swamps and shallow lakes during the summer where vegetation can be abundant. They are present in the Kobuk River system They may be an important food resource for the numerous piscivorous fish of the Kobuk River.
    Ninespine stickleback (Pungitius pungitius) are small fish which can survive in marine, brackish and fresh water though they require freshwater to spawn. They overwinter in deep waters but move to shallower waters to spawn from May to July. Their diet is mainly composed of copepods and chironomids, but they also feed upon other invertebrates and fish eggs. These fish may be an important food source for the piscivorous fish species of the Kobuk River. There is no fishery for ninespine stickleback, although they're so abundant some areas that they're used for human and dog food. Further Information

Get more info on 'Kobuk River'.

External Link Exchanges

Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:

<a href="http://kobuk_river.totallyexplained.com">Kobuk River Totally Explained</a>

Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned.