•
1992-present: Professor in marine zoology (associate professor in 1992),
University of Oslo
• Sept-Dec 2004: Guest Scientist, Woods
Hole Oceanographic Institution,
My research group exploits
the opportunities offered by easily accessible and deep fjord basins for
studies of distribution, behavior, mortality and feeding of zooplankton. Most
focus has been on the copepods Calanus finmarchicus and Paraeuchaeta
norvegica, and the krill Meganyctiphanes norvegica. Current
projects on copepods aim at unveiling state-dependent variations in vertical
distribution of P. norvegica, and assessing their feeding using
molecular methods. Projects on krill aim at characterizing swimming behavior
in relation to time of day and feeding mode, and evaluate implications for
encounters with predators. To unveil the biology of
zooplankton, it is necessary to know their predators, and studies of
distribution, feeding and swimming behavior of planktivorous fish represent a
central part of the research activities. Current projects address Norway pout
(Trisopterus esmarki), whiting (Merlangius merlangus), herring
(Clupea harengus) and sprat (Sprattus sprattus). We apply echosounders in concurrent studies of fish and plankton. To
illustrate, the echogram below displays the diel vertical migration of
macroplankton and fish at a 120 m deep site in the Oslofjord. The blue layer
located at ~70-90 m at day mainly consists of the krill Meganyctiphanes
norvegica, the fish below are Norway pout while the red layers above the
krill (most prominent the second day) consist of schooling clupeids. Test
Echogram displaying a diel cycle at a 120 m deep station, and a selected section outlining data in greater detail, showing the 3-d swimming pattern of a single fish (identified as Norway pout) at about 100 m depth. Color scales display strength of the echo (TS; left), which provides information on size, and swimming speed (right) Split-beam echo sounders hold
the opportunity of defining the position of an organism in the acoustic beam,
and by applying software allocating subsequent echoes to the same target,
so-called “target tracking” provides data on size, 3-D swimming trajectories
and swimming speed of individuals. Target tracking can normally only be done
with the echosounder (transducer) located relatively close to the targets.
Therefore, submerged systems are used to address deep-living fish. A
bottom-mounted, upward looking transducer was used to obtain the results
presented in the lower half of the figure above. Submersible systems are also
used for in situ target tracking of plankton in deep water, as
exemplified below for plankton occurring at ~80 m depth in the Oslofjord.
When lowering the transducer into what appears as a diffuse echo-layer by a
hull mounted transducer, single individuals become resolved, and individual
plankton can be studied in their natural habitat. |
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Selected publications (since 2000): |
1. Bucklin, A., Kaartvedt, S., Guarnieri, M.,
Goswami, U. (2000). Population genetics of drifting (Calanus spp.) and resident (Acartia clausi) plankton in Norwegian
fjords. J. Plankton Res. 22: 1237-1251
2. Olsen, E. M., Jørstad, T., Kaartvedt, S. (2000). The feeding
strategies of two large marine copepods. J. Plankton Res. 22: 1513-1528
3. Bagøien, S., Kaartvedt, S. Øveraas S. (2000).
Seasonal vertical migration of Calanus
spp. in Oslofjorden. Sarsia 85: 299-311
4. Kaartvedt, S. (2000). Life history of Calanus finmarchicus in the Norwegian
Sea in relation to planktivorous fish. ICES J. Mar. Sci. 57: 1819-1824
Dale, T., Kaartvedt,
S. (2000). Diel patterns in stage specific vertical migration of Calanus finmarchicus in habitats with
midnight sun. ICES J. Mar. Sci. 57: 1800-1818
5. Torgersen, T., Kaartvedt, S. (2001) In situ
swimming behaviour of individual mesopelagic fish studied by split-beam echo
target tracking. ICES J. Mar Sci. 58: 346-354
6. Bagøien, E., Kaartvedt, S., Aksnes, D.L., Eiane,
K. (2001) Vertical distribution and mortality of overwintering Calanus. Limnol. Oceanogr. 46:
1494-1510
7. Dale, T., Kaartvedt, S., Ellertsen, B.,
Amundsen, R. (2001) Large scale oceanic distribution and population structure
of Calanus finmarchicus in
relation to physical environment, food and predators. Mar Biol 139: 561-574
8. Fleddum, AL., Kaartvedt, S., Ellertsen, B. (2001)
Distribution and feeding of the carnivorous copepod Paraeuchaeta norvegica in habitats of
shallow prey assemblages and midnight sun Mar Biol 139: 719-726
9. Kaartvedt, S., Dale, T., Bagøien, E., Viken,
T. (2002) Bi-modal vertical distribution of the carnivorous copepod Paraeuchaeta norvegica. J Plankton Res
24: 155-158
10. Kaartvedt, S., Larsen, T., Hjelmseth, K.,
Onsrud, M.S.R. (2002) Is the omnivorous krill Meganyctiphanes norvegica primarily a selectively feeding
carnivore? Mar Ecol Prog Ser 228: 193-204
11. Torgersen T, Karlsbakk E, Kaartvedt S (2002) Deviating
vertical distribution and increased conspicuousness in parasitized Calanus. Limnol Oceanogr 47: 1187-1191
12. Skarra, H, Kaartvedt S (2003) Vertical
distribution and feeding of the carnivorous copepod Paraeuchaeta norvegica Mar Ecol Prog
Ser 249: 215-222
13. Klevjer, TA, Kaartvedt S (2003) Split-beam
target tracking can be used to study the swimming behavior of deep-living
plankton in situ. Aquat. Liv. Res. 16: 293-298
14. Båmstedt, U., Kaartvedt, S., Youngbluth, M.
(2003) An evaluation of acoustic and video methods to estimate the abundance
and vertical distribution of jellyfish. J Plankton Res 25: 1307-1318
15. Schøyen, M, Kaartvedt S (2004) Vertical distribution
and feeding of the copepod Chiridius
armatus Mar Biol 145: 159-165
16. Fiksen Ø, Varpe Ø, Kaartvedt S (2004) Reply to
Horizons Article ”Some ideas about the role of lipids in the life cycle
of Calanus finmarchicus”
Irigoien (2004): II J Plankton Res 26: 980
17. Onsrud, MSR, Kaartvedt S., Røstad, A., Klevjer,
T.A. (2004) Vertical distribution and feeding patterns in fish foraging on
the krill Meganyctiphanes norvegica.
ICES J Mar Sci 61: 1278-1290
18. Vestheim, H, Kaartvedt, S., Edvardsen, B (2005)
State-dependent vertical distribution of the carnivore copepod Pareuchaeta norvegica. J Plankton Res
27: 19-26
19. Vestheim H, Edvardsen B, Kaartvedt S (2005) Assessing
feeding of a carnivorous copepod using species-specific PCR. Mar Biol 147: 381-385
20. Onsrud MSR, Kaartvedt S, Breien, MT (2005) In
situ swimming speed and swimming behaviour of fish feeding on the krill Meganyctiphanes norvegica Can J Fish
Aquat Sci 62: 1822-1832
21. Kaartvedt S, Røstad A,
Fiksen Ø, Melle W, Torgersen T, Breien MT, Klevjer T (2005) Piscivorous fish
patrol krill swarms. Mar Ecol Prog Ser 299:1-5
