Pauline Nordpol Small

Pauline Snoeijs Leijonmalm


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Works at Department of Ecology, Environment and Plant Sciences
Telephone 08-16 42 46
Visiting address Svante Arrhenius väg 20 A
Room N 432
Postal address Institutionen för ekologi miljö och botanik 106 91 Stockholm

About me

In January 2008 I was appointed professor in Marine Ecology at Stockholm University. Earlier I worked at Uppsala University as professor (2003-2007), senior lecturer (1993-2003), researcher (1989-1993) and PhD-student (1982-1989) in Plant Ecology. My undergraduate degrees (BSc 1978, MSc 1982) I obtained from the Radboud University in Nijmegen, The Netherlands, with majors in Aquatic Ecology, Experimental Botany and Geobotany. For more than 25 years I have taught undergraduate and graduate courses in Marine Ecology at the Universities of Uppsala and Stockholm and I have supervised >20 and examinated >70 PhD-students.

Mobile phone: +46 704 932839


Right now I am on expedition until January 2020 - follow us at 

My research interests are biodiversity and food-web interactions. Since 1982 I have worked on the coastal and pelagic systems of the brackish Baltic Sea and since 2002 also on sea-ice ecology in the Arctic Ocean. Today the major focus of my research projects is on biodiversity and food-web interactions in the Central Arctic Ocean (CAO) ecosystem. 

The Central Arctic Ocean (CAO) is one of the last large untouched wildernesses on Earth - and it is changing incredibly fast as a result of climate change. The CAO ecosystem comprises the deep basins of the Arctic Ocean off the continental shelf and outside the Exclusive Economic Zones of the coastal countries. It is 3.3 million square km large - and nobody even knows which fish species occur in the water column! This illustrates how severely the CAO is under-investigated because it is so difficult to access. A different CAO emerges: a more dynamic ecosystem with a marginal ice zone that moves further north in summer and back again in winter. The new seasonality in melting and freezing cycles is expected to alter, inter alia, stratification, nutrient transports, biological production and species distributions.

In 2019 and 2020 I participate in two icebreaker expeditions to the CAO. During the MOSAiC Expedition with the R/V Polarstern (drifting with the sea ice in September 2019 - October 2020) we have a unique chance to document the seasonal variation of the biological and biogeochemical processes in the Central Arctic Ocean - the year-round ice-covered ecosystem as a baseline before it is too late. However, we will also document the changes a melting ice cover has on these processes in summer, and this will help us to understand the future functioning of the ecosystem. During the Swedish SAS Expedition with R/V Oden we will be in the area north of Greenland up to the North Pole and study how will functioning of the fragile marine ecosystem of the CAO is expected to change during the coming century – and how these changes can create feedback loops to greenhouse gases in the atmosphere – when the input of freshwater from melting sea ice and glaciers increases and the perennial sea ice cover becomes seasonal.

Project 2019-2022 (PI): Uncovering the seasonality of sympagic and pelagic microbial metabolic diversity, productivity and nutrient cycling in the Central Arctic Ocean

The purpose of this research project is to complement the existing knowledge on the global marine microbiome with data from the permanently ice-covered Central Arctic Ocean (CAO). This includes not only mapping the full collection of genes in the microbial communities living in different sympagic (ice-associated) and pelagic microhabitats but also to analyze gene expression, both in the field and during incubation experiments, and to relate the results to biogeochemical cycling. The specific aims of the research project are: (1) To for the first time uncover patterns in the seasonal succession of microbial metabolic functions in the CAO LME, including unknown processes that may take place during the half-year long polar night. In summer the focus is on microbial processes related to the melting of sea ice which is increasing dramatically in the CAO as a result of global warming. (2) To particularly target C and N cycling, including testing two hypotheses: (a) that diazotrophy (biological N2-fixation) is a significant source of new nitrogen to the oligotrophic CAO marine ecosystem throughout the year, and (b) that urea is an alternative substrate for ammonium oxidation and chemoautotrophic CO2 fixation in the CAO, especially in winter and at low ammonium availability. Financial support: Swedish Research Council VR, Swedish Research Council Formas, Swedish Polar Research Secretariat.

Project 2019-2022 (Consortium Coordinator): Uncovering the largest blind spot on the map of the world's fish stocks: pelagic fish, their dependence on sea ice, and their role in the Central Arctic Ocean food web

The purpose of this research project is to map the pelagic fish in the CAO. The method package for the MOSAiC expedition contains four principal methodologies that all four are necessary for collecting basic data on the presence and migration of fish in the CAO: (1) Acoustics will provide an estimate of the abundance of organisms in the pelagic zone, including the deep scattering layer in the CAO, (2) Visual observations from deep-sea cameras at ca. 400 m will tell us how many fish are in the scattering layer compared to siphonophores and jellyfish (many siphonophores and jellyfish are expected to occur in the CAO) – without these visual observations we cannot realistically estimate the fish abundance. (3) Fish sampling with different types of passive fishing gear will tell us which fish species inhabit the CAO and provide details about their distribution and ecology (size, biomass, age, maturity stages) – this is also necessary for calibrating the acoustic data and includes observations on sympagic (ice-associated) juvenile fish that can otherwise not be detected. Fish samples will be taken for later analyses, such as stomach analyses, molecular analyses and otolith studies. Population genetics will enable us to analyse the intra-specific population structure of the sampled fishes to reconstruct their origin from spawning regions. Chemical and isotopic otolith analyses will enable the reconstruction of migration pathways, age and food sources. Furthermore, (4) eDNA samples will be taken for later analyses not included in this field work project. These eDNA analyses will inform about the occurrence of rare fish species in the CAO. Similar studies will be carried out during the Swedish SAS Expedition with R/V Oden. Financial support: European Commission, Swedish Polar Research Secretariat.

International assignments

2019-2022 Coordinator of the EFICA Consortium (European Fisheries Inventory in the Central Arctic Ocean); 2016-2017 Assessment of the BONUS impact on scientific excellence and dissemination; 2016- EU representative in the FiSCAO scientific expert group on fish stocks in the Central Arctic Ocean, 2016-2017 Scientific advisor and co-organiser of an international workshop on Marine Protected Areas in the Arctic Ocean for the Swedish Agency for Marine and Water Management; 2014- Swedish country representative in the Marine WG of the International Arctic Science Committee IASC (VR); 2016- Vice-chair of WG1 in the COST Action CA15136 EUROCAROTEN (EU Horizon 2020); 2003-2013 Chair of the Advisory Board of the BONUS EU-ERAnet and the BONUS EEIG (EU); 1997-2013 General Secretary of the NGO the Baltic Marine Biologists (BMB).

Textbook: Biological Oceanography of the Baltic Sea

I am the chief editor of the first comprehensive science-based textbook on the biology and ecology of the Baltic Sea, published by Springer. Ninety-two authors, all experts in their respective research fields, have contributed with their knowledge. The aim of this book is to provide students and other readers with knowledge about the conditions for life in brackish water, the functioning of the Baltic Sea ecosystem and its environmental problems and management. The book highlights biological variation along the unique environmental gradients of the brackish Baltic Sea Area (the Baltic Sea, Belt Sea and Kattegat), especially those in salinity and climate. The book was published in april 2017 (

Some selected publications

Fernández-Gómez B, Díez B, Polz M, Ignacio Arroyo J, Alfaro F, Marchandon G, Sanhueza C, Farías L, Trefault N, Marquet P, Molina-Montenegro M, Sylvander P, Snoeijs-Leijonmalm P (2019) Bacterial community structure in a sympagic habitat expanding with global warming: brackish ice brine at 85-90 oN. The ISME Journal 13:316–333

Snoeijs-Leijonmalm P, Barnard S, Elliott M, Andrusaitis A, Kononen K, Sirola M (2017) Towards better integration of environmental science in society: Lessons from BONUS, the joint Baltic Sea environmental research and development programme. Environmental Science and Policy 78:193-209

Elliott M, Snoeijs-Leijonmalm P, Barnard S (2017) ‘The dissemination diamond’ and paradoxes of science-to-science and science-to-policy communication: Lessons from large marine research programmes. Marine Pollution Bulletin 125:1-3

Snoeijs-Leijonmalm P, Andrén E (2017) Why is the Baltic Sea so special to live in? In: Snoeijs-Leijonmalm P, Shubert H, Radziejewska T (eds.), Biological Oceanography of the Baltic Sea, Springer, Dordrecht pp. 23-84

Snoeijs-Leijonmalm P (2017) Patterns of biodiversity. In: Snoeijs-Leijonmalm P, Shubert H, Radziejewska T (eds.), Biological Oceanography of the Baltic Sea, Springer, Dordrecht pp. 123-191

Kautsky H, Martin G, Snoeijs-Leijonmalm P (2017) The phytobenthic zone. In: Snoeijs-Leijonmalm P, Shubert H, Radziejewska T (eds.), Biological Oceanography of the Baltic Sea, Springer, Dordrecht pp. 387-455

Svensson F, Karlsson E, Gårdmark A, Olsson J, Adill A, Zie J, Snoeijs P, Eklöv JS (2017) In situ warming strengthens trophic cascades in a coastal food web. Oikos 126:1150-1161

Verdugo J, Damm E, Snoeijs P, Díez B, Farías L (2016) Climate relevant trace gases (N2O and CH4) in the Eurasian Basin (Arctic Ocean). Deep-Sea Research I 117:84-94

Hylander S, Kiørboe T, Snoeijs P, Sommaruga R, Nielsen TG (2015) Concentrations of sunscreens and antioxidant pigments in Arctic Calanus spp. in relation to ice cover, ultraviolet radiation, and the phytoplankton spring bloom. Limnology & Oceanography 60:2197-2206

Turja R, Lehtonen KK, Meierjohann A, Brozinski JM, Vahtera E, Soirinsuo A, Sokolov A, Snoeijs P, Budzinski H, Devier MH, Peluhet L, Pääkönen JP, Viitasalo M, Kronberg L (2015) The mussel caging approach in assessing biological effects of wastewater treatment plant discharges in the Gulf of Finland (Baltic Sea). Marine Pollution Bulletin 97:135-149

Turja R, Höher N, Snoeijs P, Barsiene J, Butrimaviciene L, Kuznetsova T, Kholodkevich SV, Devier MH, Budzinski H, Lehtonen KK (2014) A multibiomarker approach to the assessment of pollution impacts in two Baltic Sea coastal areas in Sweden using caged mussels (Mytilus trossulus). Science of the Total Environment 473-474:398-409

Snoeijs P, Häubner N (2014) Astaxanthin dynamics in Baltic Sea mesozooplankton communities. Journal of Sea Research 85:131-143

Häubner N, Sylvander P, Vuori K, Snoeijs P (2014) Abiotic stress modifies te synthesis of alpha-tocopherol and beta-carotene in phytoplankton species. Journal of Phycology 50:753-759

Svensson F, Norberg J, Snoeijs P (2014) Diatom cell size, coloniality and motility: trade-offs between temperature, salinity and nutrient supply with climate change. PlosONE 9(10):e109993

Sylvander P, Häubner N, Snoeijs P (2013) The thiamine content of phytoplankton cells is affected by abiotic stress and growth rate. Microbial Ecology 65:566-577

Díez B, Van Nieuwerburgh L, Snoeijs P (2013) Water nutrient stoichiometry modifies the nutritional quality of phytoplankton and somatic growth of crustacean mesozooplankton. Marine Ecology Progress Series 489:93-105

Díez B, Bergman B, Pedrós-Alió C, Antó M, Snoeijs P (2012) High cyanobacterial nifH gene diversity in Arctic seawater and sea ice brine. Environmental Microbiology Reports 4:360-366

Snoeijs P, Sylvander P, Häubner N (2012) Oxidative stress in aquatic primary producers as a driving force for ecosystem responses to large-scale environmental changes. In: Abele D, Vázquez-Medina JP, Zenteno-Savín (Eds) Oxidative stress in aquatic ecosystems. Blackwell Publishing. pp. 72-88

Snoeijs P, Häubner N, Sylvander P, Nie XP (2012) Measurement of antioxidant pigments and vitamins in phytoplankton, zooplankton and fish. In: Abele D, Vázquez-Medina JP, Zenteno-Savín (Eds) Oxidative stress in aquatic ecosystems. Blackwell Publishing. pp. 389-401

Nie XP, Zie J, Häubner N, Tallmark B, Snoeijs P (2011) Why herring and sprat are weak conduits for astaxanthin from zooplankton to piscivorous fish. Limnology & Oceanography 56:1155-1167

Liu BY, Nie XP, Liu WQ, Snoeijs P, Guan C, Trui MTK (2011) Toxic effects of erythromycin, ciprofloxacin and sulfamethoxazole on the photosynthetic apparatus in Selenastrum capricornutum. Ecotoxicology and Environmental Safety 74:1027-1035

Hillebrand H, Soininen J, Snoeijs P (2010) Warming leads to higher species turnover in a coastal ecosystem. Global Change Biology 16:1181-1193

Last updated: September 14, 2019

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