Impacts of Atlantification on western Norwegian fjords over the last millennium

Background & Motivation: Over the last decade, the Arctic sea ice has reached its lowest levels since the 1850s, and future climate projections suggest that the Arctic Ocean is likely to become seasonally ice free before 2050. The recent decline in Arctic sea ice extent has been linked to increased ocean heat transport with the Atlantic Water inflow to the Arctic, known as the “Atlantification” of the Arctic Ocean. However, despite its critical importance, the natural variability of the Atlantic Water inflow into the Arctic remain poorly constrained. To contextualize ongoing changes, it is essential to understand the natural variability of the Atlantic Water inflow and its properties.

Supervisors

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

Project description

Fjord sediments provide such high-sedimentation rate archives and hold unique advantages for elucidating the effects of natural vs human-induced climate change, particularly over the 20th century. What are the impacts of Atlantification on western Norway? Were there any analogs of Atlantification over the past millennium? Located at the gateway between the western Norwegian fjords and the Norwegian Sea, Sognesjøen is strategically located to answer these questions and resolve multi-decadal changes in Atlantic Water inflow properties and the anthropogenic impacts. In this thesis, multi-species benthic foraminiferal stable isotopes (δ18O & δ13C) will be used to reconstruct physical and chemical properties of the Atlantic Water inflow, and oxygenation/ ventilation changes over the last millennium. In addition, anthropogenic signals (e.g., oceanic 13C Suess effect change) will be used to build the chronology and reconstruct the extent of the anthropogenic impact in fjord archives (industrial/pollution history).

Research questions: 

How do the Atlantic Water inflow strength and properties change over the last millennium, and what are the mechanisms underlying these changes? What is the extent of anthropogenic impact in western Norwegian fjord archives?

Work plan:
The student will work on a sediment core (multicore) 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.

To start this project, the student need to have taken GEOV110 or equivalent. 

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)
GEOF338: Polar Oceanography (Spring semester, 10 ECTS)

Last updated: 23.06.2026