Holocene decadal variability in Atlantic Water temperature and ventilation; links to large scale ocean circulation and Norwegian climate

Understanding climate variability prior to the instrumental era is essential for distinguishing natural climate variability from anthropogenically forced changes. The Norwegian continental margin is a climatically sensitive region due to its position in the path of Atlantic Water (AW) inflow; a critical component of the Atlantic Meridional Overturning Circulation (AMOC). Thus, variability in AW heat content and ventilated properties have consequences not only for Norwegian climate and environments but impact climate, weather systems, sea level, and ocean carbon and nutrient contents, and marine productivity across the circum-Atlantic and beyond.

Supervisors

Main supervisor: Ulysses Ninnemann, UiB-GEO
Co-supervisor: Nil Irvali, UiB-GEO

Prosjektbeskrivelse

Utilizing a core from a rapidly accumulated sediment drift influenced by Atlantic inflow this project aims to reconstruct decadal scale changes in AW physical properties, nutrients, and ventilation during the late Holocene. Multi-species benthic foraminiferal stable isotopes (δ18O and δ13C) records will be produced to quantify the natural variability in AW in order to establish a long-term baseline for understanding on what timescales and magnitude AW inflow and properties vary and how these are linked to Norwegian climate, productivity in the fjords, and large scale changes in ocean and atmospheric circulation.
 

Research questions:

  • How, and on what timescales, have the properties and ventilation Atlantic Water varied?
  • How have these variations impacted coastal climate, productivity, and oxygenation?
  • How do these changes compare to ongoing climate trends?
  • What is the relationship between AW heat content, ventilation, and large scale changes in the AMOC?
     

Work plan: The student will work on a sediment core recently recovered from the Sognesjøen. The core samples are partly processed, however, additional sample processing (sampling, washing/sieving) will be necessary. The main lab work will involve microscopy (identifying and picking multi-species benthic foraminifera) and high-resolution stable isotope analysis of benthic foraminifera (δ18O & δ13C) at the FARLAB.

Field-, lab- and analysis work

Lab work ca. 6 months, including sample processing, microscopy and stable isotope analysis

Proposed course plan

Fall semester H26:
GEOV222: Palaeoclimatology (10 ECTS)
GEOV324: Polar Palaeoclimate (5 ECTS)
GEOV300: Scientific writing and communication in Earth Science (5 ECTS)
 

Spring semester V27:
GEOV231: Marine Geological Field-and Laboratory Course (10 ECTS)
GEOV331: Paleoceanography (5 ECTS)
GEOF337: Physical Oceanography in Fjords (10 ECTS)
GEOV342: The geochemical toolbox (10 ECTS)
GEOV322: Master Level Field Excursion in Quaternary Geology (5 ECTS)
 

Alternative Course Suggestions:
GEOV302: Data analysis in earth science (Spring semester, 10 ECTS)
GEOV329: Quaternary geochronology (Spring semester, 10 ECTS)
GEOF338: Polar Oceanography (Spring semester, 10 ECTS)

Last updated: 23.06.2026