PowerPointpresentasjon

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Cecilie Broms and Webjørn Melle
Large-scale distribution and abundance of
Calanus species in relation to environmental
factors
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Norwegian Coastal water
Atlantic water
Arctic water
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• Geographical distribution of Calanus species
  within the North-east Atlantic
• and Polar oceans
• C. finmarchicus
• Northern boreal species
• Widely distributed in the North-Atlantic
• Centres of distribution the sub-polar
• gyre south of Greenland and the gyre of the
• southern Norwegian Sea
• C. glacialis
• Arctic shelf species
• Abundant in Arctic water masses in the
• Barents Sea.
• Found in low abundance in the deeper
• Greenland, Iceland and Norwegian Seas.
• C. hyperboreus
• Arctic species

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• Geographical distribution of Calanus species
  within the North-east Atlantic
• and Polar oceans
• C. finmarchicus and C. hyperboreus are
• important prey for planktivorous pelagic
• fish as NSS herring, mackerel, capelin
• and blue whiting.

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Aims

• Examine the distribution and abundance of C.
  finmarchicus,
• C. glacialis and C. hyperboreus in the
  Norwegian Sea
• Identify environmental factors implying the
  distribution of Calanus species
• Examine how the distribution of Calanus species
  were affected by
• these environmental factors.

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Working hypotheses

• C. finmarchicus is abundant in Atlantic water.
• C. glacialis and C. hyperboreus are restricted
  to cold Arctic water
• Temperature is an important environmental factor
  affecting and restricting
• the distribution of Calanus species.
• The current system affects the distribution of
  Calanus species.

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Material Methods

• Six cruises from March August
• 102 stations
• - Salinity
• - Temperature
• - Chlorophyll a
• - Nitrate
• - Zooplankton (MOCNESS)
• Covering the growth season of Calanus
• in the Norwegian Sea
• Covering Norwegian Coastal water,
• Atlantic water and Arctic water

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C. finmarchicus abundance and distribution in the
Norwegian Sea

• Highest abundance in Atlantic water
• Low abundance in Norwegian
• Coastal water and Arctic water
• Arctic front seems to be the
• north-western boarder

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C. glacialis abundance and distribution in the
Norwegian Sea

• Low abundance in the Norwegian Sea
• Highest concentration in north-east,
• probably entering the Norwegian Sea
• from the Barents Sea.

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C. hyperboreus abundance and distribution in the
Norwegian Sea

• Highest abundance in Arctic water
• Low abundance in Norwegian
• Coastal water and Atlantic water
• The Arctic front north-west in the
• Norwegian Sea restricts the
• distribution

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Transect covering the Norwegian Coastal water,
Atlantic water and Arctic water in May
Transect across the Norwegian Sea between 69º
and 71º north Covering Norwegian Coastal
water, Atlantic water and Arctic water 12
stations high-lighted with red
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Relative abundance of Calanus species from
Coastal, through Atlantic, to Arctic water
Coastal water
Atlantic water
Arctic water
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Principal Component Analysis (PCA) biplot of
Calanus species
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1. PCA axis Abundance of Calanus, mainly
governed by C. hyperboreus

• Norwegian Coastal water
• Low abundance of C. hyperboreus
• North of Lofoten all three Calanus
• species found

• Atlantic water
• Sporadic and low abundance of
• C. hyperboreus
• Arctic water
• Intermediate abundance of C.
• hyperboreus in Arctic water in south-west
• High abundance of C. hyperboreus in
• north-west

Jan Mayen
Iceland
Norway
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2. PCA axis Calanus species distribution

• C. finmarchicus dominates Atlantic
• water in central Norwegian Sea
• C. glacialis and C. hyperboreus are
• found in Arctic water.
• C. hyperboreus belonging to fjord
• populations are observed along
• the Norwegian Coast

Jan Mayen
Iceland
Norway
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Redundancy Analysis (RDA) triplot of Calanus
species versus environmental variables
Environmental variables
Responce variables
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Responce of C. finmarchicus abundance versus
temperature using Generalized Additive Models
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Response of C. glacialis and C. hyperboreus
abundance versus temperature using Generalized
Additive Models
C. glacialis
C. hyperboreus
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Adaptations to low water temperatures and Arctic
environment

• Large body size
• Survive longer periods without feeding in areas
  with longer unproductive seasons
• and unpredictable feeding environment

• Reproduction
• Spawning well in advance of the phytoplankton
  bloom with larvae surviving for a long
• period without feeding
• Makes the new generation ready to take advantage
  of the short and variable
• spring phytoplankton bloom

• Life cycle
• Two- or multi-year life cycle
• Ability to survive as young copepodites if not
  reaching near-adult stages before
• overwintering.

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Conclusions

• Calanus finmarchicus is abundant in Atlantic
  water, while C. glacialis and
• C. hyperboreus are restricted to Arctic water
  in the Norwegian Sea.
• C. glacialis is less abundant in the Norwegian
  Sea
• The Arctic front seems to be the north-western
  boarder between the
• distribution area of C. finmarchicus and C.
  hyperboreus

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Conclusions

• Temperature and the circulation system are
  probably important
• environmental factors affecting and
  restricting the distribution
• of Calanus species.
• Temperature may also be a proxy for potentially
  mis-match between
• the feeding nauplii and copepodite stages of
  C. finmarchicus in Arctic water
• and the phytoplankton bloom