Dissertation on zooplankton in Svalbard

Dissertation on zooplankton in Svalbard

Top image: Calanus hyperboreus is one of the zooplankton species Malin Daase has focused on in her PhD thesis. Photo: Malin Daase/UNIS.

Research done by PhD candidate Malin Daase indicate that a warmer Arctic ocean will result in changes in the zooplankton populations, which will affect fish, bird and mammals that prey on these populations. Daase will defend her PhD thesis on 6 February 2008 at UNIS.

5 February 2008
Press release from the University Centre in Svalbard (UNIS) and the University of Bergen

To understand how climate change affects the Arctic marine ecosystems, it is necessary to increase our knowledge about species composition and species distribution and adjustments in behavior- and life history options of the ecologically important species.

In her thesis Malin Daase has studied how the zooplankton community varies in the Svalbard waters. In this part of the Arctic, the inflowing Atlantic water ensures that the southern and northern zooplankton species coexist.

Daase’s thesis describes geographical variations in the zooplankton communities mainly as a result of differences in the variety of species and not as a result of clear differences in taxonomic composition. Daase also quantifies the relationships between environmental variabilities as hydrography and bathymetry and the distribution of dominating zooplankton species.

Can coexist
The Atlantic species Calanus finmarchicus; Calanus glacialis and Calanus hyperboreus are ecologically very important in the investigated area. In her thesis, Daase analyzes these species especially and investigates more thoroughly how their distribution is related to the environmental variation.

Observations done over a year of Calanus populations in one of the Svalbard fjords, indicates that it is probable that these three species can coexist in the Arctic environment. Daase also investigates whether the difference in vertical distribution of Calanus populations could be explained by the difference in light conditions and mortality rates.

Further, Daase developed quantitative models for how the amount of Atlantic and Arctic Calanus species vary according to the water mass quality. These studies show that a further warming of the ocean may result in a reduction in the amount of the relative big Arctic Calanus species, whereas there would be an increase in the amount of the smaller Atlantic species.

The models indicate that the total Calanus biomass would not change significantly in the studied area. This could have significance for those fish, bird and mammal species that feed on the Calanus and that depend on zooplankton of a certain size for survival.

Malin Daase

Malin Daase

Malin Daase defends her PhD thesis “Mesozooplankton distribution in Svalbard waters: Calanus spp. and its relationship to hydrographic variability” at UNIS on 6 February. Daase will give a trial lecture called “Trophodynamic relations in temperate and arctic pelagic food webs” the same day.

About the candidate
Malin Daase (born 1974) is from Hamburg, Germany. She has a Master’s degree (Diplom Biologe) from the University in Kiel, Germany in 2001.

Her PhD work has been carried out at the University Centre in Svalbard (UNIS).

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