Title of thesis:
Diel and seasonal vertical migrations of high-latitude zooplankton: knowledge gaps and a high-resolution bridge

Title of trial lecture:
Allometric scaling in marine ecosystem models - strengths and weaknesses.

Time of trial lecture: 10:15 - 11:15
Time of defence:  12:15 - 15:30
Place: Auditorium Petter Thomassen (A5)

Members of the evaluation committee:
- Professor Mark D. Ohman, Scripps Institution of Oceanography, University of California San Diego, USA  
- Researcher Espen Strand, Research Group Plankton / Institute of Marine Research, Bergen 
- Associate Professor Vigdis Tverberg, FBA, Nord   university (leader)

Supervisory Committee: 
Main supervisor: Professor Ketil Eiane, FBA
Co-supervisors: 
- Professor Øystein Varpe, UNIS, Svalbard
- Associate Researcher Rubao Ji, Woods Hole Oceanographic Institution, Department of Biology, Falmouth, USA

The PhD trial lecture and defence are open to the public. The thesis is available on request. Please contact Jeanett Stegen, email: jeanett.stegen@nord.no, phone: 75 51 74 49 

About the thesis:
Toward a better understanding of vertical migrations of high-latitude zooplankton: Periodic appearance and disappearance of zooplankton from surface layers of lakes and oceans puzzled naturalists for many years. By the late-19^th century, undisputable evidence was brought forth to suggest that these patterns are caused by zooplankton vertically migrating to deeper waters and back. Based on the periodicity, two such migratory behaviors exist among high-latitude zooplankton: the diel vertical migration and seasonal vertical migration. 

Despite been a subject with a long research history, knowledge gaps still exist about how these migrations are controlled, and how diel and seasonal vertical migrations collectively influence growth, survival and reproductive tactics of high-latitude zooplankton. Kanchana's thesis, titled “Diel and seasonal vertical migrations of high-latitude zooplankton: knowledge gaps and a high-resolution bridge” is an attempt to bridge these knowledge gaps using year-round field data and high-resolution models. 

Findings of the study suggest that studying zooplankton vertical migrations in high-resolution produces rich biological information about how vertical migrations are regulated by the environmental variables. The high-resolution models employed in this study further emphasized that predation risk has a greater influence on vertical migrations than food availability or temperature.