Introduction to the Circumpolar World The marine environment Hreiðar Þór Valtýsson, MSc in...

Introduction to the Circumpolar WorldThe marine environment

Hreiðar Þór Valtýsson, MSc in Fisheries BiologyAssistant Professor, Faculty of Business and Science, University of Akureyri

Director, the Fisheries Sciences Center at the University of AkureyriBorgir (2nd floor, office 228), Norðurslóð, 600 Akureyri

Tel.: 460 8920 (office)E-mail: [email protected]

Office hours: By appointment

mailto:[email protected]

Introduction

Subject: The Arctic marine environment, biological processes and fisheriesReadings:1. ACIA 2004: Key Finding No. 4: Animal species´ diversity, ranges, and distribution will change; p. 58-.67.

Locate on ACIA web page at: http://www.acia.uaf.edu/pages/overview.html 2. Arctic flora and fauna – status and conservation: Chapter 8 – The Oceans and seas. Locate on CAFF

web page at: http://arcticportal.org/uploads/eX/e6/eXe6XNMebXN263nFyvx_Rg/AFF-Status-and-Trends.pdf

3. Fisheries.is - Information on Icelandic fisheries from A to Z. Find about the species discussed in the overheads under "main species" and information on the marine ecosystem around Iceland under "Ecosystem"

Supplementary material if you want to learn more about this topic: 4. ACIA Scientific report:

1. Chapter 13 – Fisheries and aquaculture, Central North Atlantic – Iceland and Greenland (section 13.1, p. 692-695 and section 13.3, p. 709-731). Locate on ACIA web page at : http://www.acia.uaf.edu/pages/scientific.html.

2. Chapter 9 – Marine systems. Locate on ACIA web page at : http://www.acia.uaf.edu/pages/scientific.htm

5. BCS 311: Land and Environment I :1. Module 8 – Life in the ocean: http://www.uarctic.org/singleArticle.aspx?m=500&amid=3167

2. Module 11 – Living Resources in the Arctic Marine Environment: http://www.uarctic.org/singleArticle.aspx?m=500&amid=3167

6. More on my website http://staff.unak.is/hreidar/index.htm, click NOR0173

NOR0173 Hreidar Thor Valtysson The web

http://www.acia.uaf.edu/pages/overview.html

http://arcticportal.org/uploads/eX/e6/eXe6XNMebXN263nFyvx_Rg/AFF-Status-and-Trends.pdf

http://arcticportal.org/uploads/eX/e6/eXe6XNMebXN263nFyvx_Rg/AFF-Status-and-Trends.pdf

http://www.fisheries.is/

http://www.fisheries.is/

http://www.acia.uaf.edu/pages/scientific.html



http://www.uarctic.org/singleArticle.aspx?m=500&amid=3167

http://www.uarctic.org/singleArticle.aspx?m=500&amid=3167

http://staff.unak.is/hreidar/index.htm

http://staff.unak.is/not/hreidar/index.htm



Introduction

1. Key ecological aspects of the Arctic marine environment

2. Introduction to the main species3. Key findings #4 - Animal species´ diversity

ranges and distribution will change4. The marine ecosystem in Iceland and adjacent

waters

Further information on http://staff.unak.is/hreidar/index.htm

(click on NOR0173 in the left upper corner)

PASSWORD FOR DOCUMENTS = fish


http://staff.unak.is/hreidar/index.htm




Introduction


• The Arctic is a mediterranean sea plus some tundra and ice !!

• Fisheries and other marine harvest therefore very important for Arctic people

• The next lectures will be about the Marine environment in the Arctic

• The focus is on the Northern Atlantic/Arctic but the species are mostly the same in all areas




1. Ecology


The Arctic is in may ways unique

• High proportions of continental shelves and shallow waters => higher productivity




1. Ecology


The Arctic is in may ways unique• A very high seasonality in sunlight => highly seasonal primary production




1. Ecology


The Arctic is in may ways unique• Little overall sunlight and thus cold sea temperatures• Strong influence of fresh water in the high Arctic• Seasonal or permanent sea ice• Intense mixing of seawater in the winter => plenty of nutrients• Demands special adaptation by animals and plants




1. Ecology


Sea ice• Some mammals depend very much on it

such as polar bears and some seal species

• It scours the bottom in shallow areas => destroys bottom life

• However algae thrive on the underside of it in spring, driving the production in the ecosystem




Introduction


Cold and warmer currents meet => very high productivity

High inflow of freshwater from rivers

Polar fronts River inflow




1. Ecology


Arctic marine animals• Tend to grow slow and live long => slow reproductive rate• A few groups that live in unstable environments the opposite,

grow fast, live short => high reproductive rate• Many are able to store large quantities of energy rich lipids

(fat) to survive high variability of food abundance – Arctic animals are generally fat– Also serves as insulation in mammals

• Way to survive the winter– Tolerate it – one has to be tough– Migrate – one has to be easy traveler– Hibernate – one has to find a good spot




1. Ecology


• The ecosystem is simple (i.e. species diversity is low) compared to warmer waters

• But: individual species can however reach extremely high abundance




1. Ecology


• The oceans are divided into different areas where organisms live. Organisms are also divided into several groups by where and how they live, the most simple division is:

– Benthos (botnlífverur ) – Live on or in the bottom, some are stuck to the bottom

– Pelagic (uppsjávarlífverur ) – Live in the water mass • Plankton (svif ) – Limited ability to

move, dependent on currents– Phytoplankton

(Plöntusvif eða svifþörungar )– Zooplankton (dýrasvif )

• Nekton (sunddýr) – Can move wellMany are benthic




1. Ecology


• An extra way of life is found in the Arctic called Epontic.

• Species that live on the underside of ice (inverted bottom)




1. Ecology


• The phytoplankton is the base of the ecosystem

• Single celled algae that cannot be seen by naked eyes

• Eaten by zooplankton => eaten by small fish => eaten by seals => eaten by polar bears (simplyfied)

• Dead zooplankton and animals sink to the bottom => eaten by benthic invertebrates => eaten by other animals




2. Phytoplankton


Fundamental problem in the ocean1. Phytoplankton need sunlight and nutrients (such as nitrogen and phosphates)

to be able to photosynthesize 2. Sunlight only available in the uppermost layers (ca 20 depth)3. As nutrients are quickly used up by phytoplankton they would not be available

in the upper layers under normal circumstances4. This is indeed the case in tropical waters and as a result they are very

unproductive5. To escape this problem the seawater needs to be mixed regularly to bring the

nutrient rich deep waters up to the sunlight6. This is one of the reasons the areas where cold and warm currents meet are

very productive, this collision of currents causes mixing7. There is however another factor that causes the Arctic waters to be unusually

productive




2. Phytoplankton


Primary productivity in the ocean (cold temperate waters)1. Winter

a) Surface waters are cooled by cold weather => more dense => sink => nutrient (primarily N and P) rich deep waters up instead – very intense mixing

b) However, limited sunlight => primary production low2. Spring

a) Surface waters rich in nutrients after mixing in winterb) Enough sunlight => primary production very high

3. Summer (this applies for the whole year in the tropics but is very short in the high Arctic)

a) Plenty of sunlight but ...b) Surface waters warm => surface waters less dense than deep waters => stratification (no

mixing) => algae finish up nutrients => Primary production low4. Autumn

a) Surface waters are cooled by colder weather => more dense => sink => nutrient (primarily N and P) rich deep waters up instead

b) Some sunlight => primary production rather high




2. Benthic algae


• The main primary producers in the sea are

– Phytoplankton (mentioned before), small and unicellular, but provide most of the production

– Benthic algae or seaweed, large and multicellular but only in a narrow zone along the coast

• Benthic algae form kelp forests in cold and temperate oceans which are very productive and important ecosystems

• Only in shallow waters, to about 30 m• Not as important for the ecosystem as the

phytoplankton, but important as food for some species (e.g. sea urchin) and shelter for other (e.g. juvenile cod).




2. Zooplankton


• Copepods, for example Calanus species (rauðáta og póláta) , euphausids (ljósáta) and hyperiids (sviflægar marflær) the most prominent

• Not utilized directly by humans, but is vital link between phytoplankton and fish

• Eat phytoplankton and other zooplankton

• Many commercially important species, such as cod are planktonic at young age




2. Benthic invertebrates


• Much more diverse than the zooplankton

• Eat detritius, carrion, plankton and other benthos

• Some species harvested and have become quite important recently.

Norway lobster Northern shrimp

Green sea urchin

Iceland scallop

Whelk

Blue mussel

Ocean quahog




2. Fishes (Atlantic part)

Benthic fishes Pelagic fishes

Northerners

SouthernersNOR0173 Hreidar Thor Valtysson The web

Saithe - ufsiHaddock- ýsa

Sandeel - sandsíli

Blue whiting- kolmunni

Herring - síldLumpsucker - hrognkelsi

Cod - þorskur

Greenland halibut- grálúða

Greenland shark - hákarl

Polar cod - ískóð

Capelin - loðna

Salmon - lax

Redfish - karfi




2. Marine mammals


• The Arctic is in fact a heaven for mammals and birds• Very few places in the world have as high densities of large

mammals• Mammal hunting therefore very important for the people of the

high Arctic• Due to the warm blood and active lifestyle these animals have

an advantage in the cold• In comparison few species of cold blooded animals have

managed to adapt to the Arctic although the few species that have can be really abundant, there is for example only one species of shark in the Arctic, Greenland shark

Polar bear- ísbjörn




2. Whales (Icelandic)


High Arctic species




2. Seals (N. Atlantic)


Grey seal - útselur

• The only species that breed in Icelandic waters are the common and the grey seals• Others are true Arctic seals, most common along the sea Ice and vagrants here

Ringed seal - hringanóri

Bearded seal - kampselur

Northerners

Southerners

Hooded seal - blöðruselur

Harp seal - vöðuselur

Grey seal - útselurHarbor seal - landselur

Walrus - rostungur




2. Seals (Akureyri)


Ringed seal - hringanóri

Bearded seal - kampselur

Hooded seal pup - blöðruselskópur

Harp seal - vöðuselur

Grey seal - útselur

Harbor seal - landselur

Walrus - rostungur




2. Seabirds


Are warm blooded and can therefore live in all climates

All seabirds nest on land, often in large colonies

Seabirds are very abundant in the Arctic

The puffin is the most abundant seabird in Iceland with 2 to 3 million breeding pairs, the fulmar is next

Feeding habits are diverse, eiders live on benthic invertebrates, cormorants and auks are active hunters, and gulls are scavengers




3. Key findings #4

Polar bears• Mostly eat ice-living seals• Among the animals that most dependent on

ice• Unlikely to survive as a species if the sea ice

disappears • Already documented changes in the Hudson

Bay (Canada)• Polar bears are long lived and at the top of

the food chain• Therefore they accumulate toxic chemicals in

the liver fat• These chemicals are persistent in the Arctic





3. Key findings #4

Ice-dependent seals• Ringed seals probably the most

affected• Spend their entire life on ice

– Forage under or near the ice– Need enough ice to build lairs– Need ice cover to protect pups

• Although the ringed seal is the most dependent on ice other high Arctic species would also suffer


• Harbour and Grey seals from warmer climates would however thrive as new areas would be opened up for them




3. Key findings #4

Walrus• As strange as it might sound, if the Arctic warms up walruses, other

marine mammals and some birds might decline because of competition with warmer water fishes.

• The walrus also depends on shallow waters, if the ice edge retreats from the continental shelf two bad things might happen to the walrus


1. Productivity is very high at the edge of the ice, this in turn supports rich bottom life that the walrus feeds on. If the edge retreats over deeper waters the walrus will no longer have the same food supply

2. The walrus uses the ice to rest on, therefore it needs to be close to the feeding grounds




3. Key findings #4

Algae• Most of the production in the lower Arctic is driven by ice-

algae• Warming might (and probably has) cause these species to be

replaced by less productive species





3. Key findings #4

Additional threats• Warmer climates => increased risk of diseases• Animals in colder waters are not resistant to these• More precipitation is predicted and this can lead to increased pollution,

but pollution is already a problem in the Arctic• Less ice => more shipping => more accidents => more pollution• More ultraviolet radiation largely due to depletion of ozone (key finding

#9) => many species are vulnerable to this => less production





3. Key findings #4

Fishes and fisheries• High Arctic species will decline in

numbers• The species are however few and of

little commercial interest• Low- or subarctic species might

however increase in numbers or simply move further north as their normal distributional range gets to warm

• Many of these are of great commercial interest

• Commercial fisheries will benefit





3. Key findings #4

Fishes and fisheries• Great changes have already been

observed in the Bering Sea• Walleye pollack fishery now among

the largest fisheries in the world





3. Key findings #4

Fishes and fisheries• Lesser changes are expected in the

short run in the Atlantic• But there are already some signs of

warming there, more later …..• There we also have a good example

of dramatic collapse of a fishery due to climate change

• However this was not due to warming but cooling + other factors

• About 900.000 t were caught of Newfoundland cod at its peak, now there is almost no fishery allowed





3. Key findings #4

Fishes and fisheries• Humans are however very adaptive• Collapse of the cod in Newfoundland led to

an great increase in the shrimp and crab fisheries (previously eaten by cod)

• Fishery for those is now actually more valuable than the cod fishery before

• Warming trend in Greenland also meant that seal numbers decreased and cod numbers increased

• Former sealers therefore became cod fishers and profited well

• A shift in the other direction is however more difficult





3. Key findings #4

Summary of threats to Arctic species due to warming• More competition with species from warmer waters• Less or different less suitable food• Loss of suitable habitat• Increased risk of diseases• More pollution• More human traffic

Conclusion• If the Arctic will continue to warm it will probably still be teaming with

life• This will however be very different from the current as warmer water

species will move in and pure Arctic species will retreat north • It is however impossible to retreat further north when you are on the

North Pole





3. Key findings #4

NOR0173 Spring 2008 Hreidar Thor Valtysson The web

Next fisheries in Iceland and climate change


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