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Alaska Map. Alaska Geography Facts I. 663,268 sq miles, including territorial waters 21% of the area of the entire lower 48. Bounded by: Gulf of Alaska Bering Sea Chukchi Sea Beaufort Sea (Arctic Ocean). Alaska Geography Facts II. Width: West - East 808 miles

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alaska geography facts i
Alaska Geography Facts I

663,268 sq miles, including territorial waters

21% of the area of the entire lower 48.

Bounded by:

Gulf of Alaska

Bering Sea

Chukchi Sea

Beaufort Sea (Arctic Ocean)

alaska geography facts ii
Alaska Geography Facts II

Width: West - East 808 miles

Length: North - South 1,479 miles

Controlled by Federal Gov’t: 65% total area

Shoreline: 34,000 miles

Two Time Zones: Alaskan Aleutian

Population (2006) 670,053

alaska geography facts iii
Alaska Geography Facts III

Coastline Alaska: 33,904 miles

Coastline Lower 48: 54,729 miles

Alaska has 62% total Tidal Coastline of US

Area of Continental Shelf in Alaska is huge

Most fish are caught near shore and on the continental shelf

geology of alaska i
Geology of Alaska I

Two Major Tectonic Plates

North American Plate & Pacific Plate

Understanding Plate Interactions Important

Transform Boundary - sliding along

Divergent Boundary - mid ocean ridge

Convergent Boundary - subduction zone

geology of alaska ii
Geology of Alaska II

North American Plate: NA Craton is the Core

NA Craton Rock: North/East corner of Alaska

Remainder of Alaska is accreted terrain, rocks from further south that have been sequentially transported to Alaska by Plate Tectonics. Many different terrains.

Continental Shelf is part of the Continental Plate

Kula Plate - Oceanic plate subducted under NA but a last fragment accreted to shallow Bering Sea shelf.

plate tectonics
Plate Tectonics

Oceanic versus Continental Plates

Ocean Spreading Centers

Mid-Oceanic Ridge

Volcanic Activity - Black Smokers


Continental Plates Override Oceanic Plates

Oceanic Plates dive into Subduction Zones

alaska marine map
Alaska Marine Map

Beaufort Sea

Chukchi Sea

Gulf of Alaska

Bering Sea

alaskan marine regions
Alaskan Marine Regions

Southeast Alaska Inland Waters

Gulf of Alaska Coast

Western Gulf of Alaska

Alaska Peninsula

Bering Sea

Yukon Kuskokwim Delta

Aleutian Islands

Seward Peninsula Norton Sound

Chukchi Sea

Beaufort Sea

freshwater alaska
Freshwater Alaska

More than 3 million lakes in Alaska

Marshland & Wetland Permafrost Account for

188,320 sq mi of territory

Alaska has 12,000 rivers, many with salmon runs

51 Tidewater Glaciers

Many Glaciers feed Rivers, Marshes and Lakes

geology fishing
Geology & Fishing

What does this have to do with fishing?

1. Nutrients eroded from rock feed food web

2. Ocean spreading centers & nutrients

3. Volcanism from subducted plates & nutrients

4. Freshwater Habitat for anadromous fish

5. Seamounts bring huge diversity

6. Fish Predators live on land

alaskan climate
Alaskan Climate

Latitude: 51° 20’ North to 71° 50’ North

Longitude: 130° West to 172° East

Record High Temp: 100°F Fort Yukon

Record Low Temp: -80°F Prospect Creek

Sea Ice: Cook Inlet, Bering, Chukchi and Beaufort Seas.

global warming
Global Warming

What will be the effects of Global Warming?

1.Warmer water species will migrate north

2.Colder water species will migrate north

3. Ocean currents will change

4. Potentially profound effects on species distribution and abundance

regional climate change
Regional Climate Change

El Niño &La Niña:

Short term climatic fluctuations

1997 El Niño

1. Weird milky algal bloom in Bering Sea visible from space.

2. Implicated in protist infestations of many

commercial species.

pacific decadal oscillation
Pacific Decadal Oscillation

PDO is a pattern of Pacific climate variability that shifts phases on at least inter-decadal time scale, usually about 20 to 30 years

PDO provokes a faunal regime shift, where the animals found most abundantly change in cold to warm and warm to cold shifts.

Cold - crab, shrimp, herring, capelin

Warm - cod, pollock, salmon

pacific decadal oscillation1

Pacific Decadal Oscillation

Cold Phase Warm Phase

pdo index
PDO Index

The PDO Index is calculated by spatially averaging monthly sea surface temperature of the Pacific Ocean north of 20°N. The global average anomaly is then subtracted to account for global warming. Only October to March values are used because year-to-year fluctuations are most apparent during the winter months.

geology fisheries
Geology & Fisheries

Nutrient Input (Limiting Minerals)

1. Deep-Water Upwelling

2. Loess - Wind Borne Dust

3. Volcanic Ash

4. Tidewater Glaciers

5. Suspended Riverine Sediments

6. Nutrients Released at Ice Edge

Algae Require Mineral Micro-Nutrients

temperature light and nutrients control algal blooms
Temperature, Light and Nutrients Control Algal Blooms

1. Growth of some algal species limited by nutrient availability (eg. Silica & Iron .

2. With appropriate nutrients, temperature and light regulate bloom growth rates.

3. Long days in late spring can promote huge blooms.

4. Single cell algae are the base of marine food chains.