Species of crustacean
Calanus finmarchicus
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Scientific classification
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Domain:
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Eukaryota
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Kingdom:
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Animalia
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Phylum:
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Arthropoda
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Class:
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Copepoda
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Order:
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Calanoida
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Family:
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Calanidae
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Genus:
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Calanus
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Species:
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C. finmarchicus
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Binomial name
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Calanus finmarchicus
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Synonyms
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List
- Calanus arietis
Templeton, 1836
- Calanus borealis
Lubbock, 1854
- Calanus elegans
Lubbock, 1854
- Calanus mundus
Dana, 1849
- Calanus perspicax
Dana, 1852
- Calanus quinqueannulatus
Krøyer, 1842
- Calanus recticornis
Dana, 1849
- Calanus sanguineus
Dana, 1849
- Calanus septentrionalis
(Goodsir, 1843)
- Calanus spitzbergensis
Krøyer, 1843
- Cetochilus finmarchicus
(Gunner, 1765)
- Cetochilus septentrionalis
Goodsir, 1843
- Cyclops finmarchicus
Muller O.F., 1776
- Monoculus finmarchicus
Gunner, 1765
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Calanus finmarchicus
is a species of
copepod
and a component of the
zooplankton
, which is found in enormous amounts in the northern Atlantic Ocean.
Distribution and ecology
[
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]
Calanus finmarchicus
is most commonly found in the
North Sea
and the
Norwegian Sea
. It is also found throughout the colder waters of the North Atlantic, especially off the coast of Canada, in the
Gulf of Maine
, and all the way up to western and northern
Svalbard
.
Calanus finmarchicus
is one of the most commonly found species of zooplankton in the subarctic waters of the North Atlantic. Sometimes confused with
C. helgolandicus
and
C. glacialis
,
C. finmarchicus
is a large planktonic
copepod
whose chief diet includes
diatoms
,
dinoflagellates
, and other
microplanktonic
organisms. In fact, some studies have shown that
heterotrophic microplankton
provide a "prey resource sufficient for net
lipid synthesis
as well as egg production".
[1]
C. finmarchicus
is a key component in the
food web
of the North Atlantic, providing sustenance for a variety of marine organisms including fish, shrimp, and whales.
Although the organism prefers these types of habitats, it has demonstrated that it is capable of surviving a wide range of environmental conditions. In terms of depth,
C. finmarchicus
can be found living anywhere from the ocean surface down to about 4,000 metres (13,000 ft) deep. It can also live in waters as cold as ?2 °C (28 °F) and as warm as 22 °C (72 °F). Other environmental conditions and their ranges include
salinity
(18?36 pps), oxygen (1?9 mL/L),
nitrate
(0?45 μmol/L),
phosphate
(0?3 μmol/L) and
silicate
(1?181 μmol/L) levels.
[
citation needed
]
Calanus finmarchicus
primarily feeds on different forms of
phytoplankton
. This includes diatoms, dinoflagellates,
ciliates
, and other
photosynthetic
marine organisms. Some scientific evidence suggests that copepods like
C. finmarchicus
are feeding on microzooplankton as well.
[2]
Mesozooplankton
are among the most important components of their regional food web. Several species of harvestable fish, including
cod
,
herring
and
red fish
(along with a plethora of other marine life) depend on
C. finmarchicus
for some form of nourishment. Scientists working in Canada estimate that 90%?100% of larval redfish prey on
Calanus
eggs in the Gulf of the St. Lawrence.
[1]
Calanus finmarchicus
is especially important ecologically because it shows rapid responses to climate variability, including shifts in species' distribution and abundance, timing of life history events, and
trophic relationships
.
[3]
Physiology
[
edit
]
Calanus finmarchicus
is considered to be a large copepod, being typically 2?4 millimetres (0.08?0.16 in) long.
[
citation needed
]
Copepods like
C. finmarchicus
represent a major part of
dry weight (biomass)
mesozooplankton in
pelagic
ecosystems.
[4]
Calanus finmarchicus
is high in
protein
and
polyunsaturated
omega-3
fatty acids
.
[5]
Calanus finmarchicus
has survived intense periods of climate change. During the
last ice age
(approx. 18,000 years ago), the species migrated north in order to maintain its large populations.
[6]
The organism's
overwintering
strategy, known as
diapause
, gives it the ability to survive during long periods of food shortage, typical of temperate and high latitudes.
[7]
During this six-month period of hibernation, many of these organisms will sink to depths of 500?2,500m in the ocean, where they remain at rest until the following spring when they awake and return to the surface waters to breed.
[8]
Many scientists believe that
C. finmarchicus
use this strategy as a survival method by reducing physiological costs and predation risk.
[9]
This ability leads scientists to believe that they may be able to track some of the current changes in climate using the habits of these planktonic organisms.
The overwintering strategy employed by
C. finmarchicus
helps it survive intense starving periods and plays a significant role in the organism's life cycle. During these starving periods
C. finmarchicus
has shown that it is able to maintain a consistent rate of egg production as well as a constant proportion of
adenosine triphosphate
(ATP) to carbon; granted their absolute amounts of
carbon
,
nitrogen
, and ATP vary significantly.
[10]
Scientists look at these levels of ATP because they usually remain constant over a range of physiological conditions, making them useful indicators of biomass.
[10]
Both egg production and ATP composition were previously thought to have varied directly with food availability on a linear scale. More recently, it has been shown that despite low concentrations of phytoplankton (one of the organism's primary food sources),
C. finmarchicus
maintained relatively high rates of egg production. In fact, these rates were strikingly similar to the egg production rates of those recorded in the lower St. Lawrence estuary, where the water had a much higher concentration of
chlorophyll
(indicating a larger presence of phytoplankton).
[1]
Adults reproduce almost exclusively in surface waters.
[9]
Calanus
eggs are typically 0.05 mm (0.0020 in) in diameter, and hatch in 2?3 days.
[11]
See also
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References
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External links
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