[{"_id":"project:1824","_type":"project","abstract":{"en":"The Baltic Sea has low surface salinity and a steep halocline with anoxic bottom areas. The total reserves of nitrogen in the Baltic have been rising, and denitrification is a key process in balancing the nitrogen budget. We propose to study whether anammox bacteria contribute to denitrification using environmental genomics. We will also use such techniques to study the overall diversity and extent of stratification of microbial species in the water column and sediments across a steep oxygen gradient. We will study microbial diversity (archaeal and bacterial) using 16S ribosomal RNA gene and metagenomic sequencing, and in addition, will develop ribonucleotide reductases as novel biomarkers for oxic-anoxic habitability.  The study has a clear environmental relevance since virtually nothing is known about the anammox reaction in the Baltic Sea. There is also a potentially interesting evolutionary perspective, as the anammox bacteria form a distinct monophyletic group within the Planctomycetes, an enigmatic group of bacteria with internal cell structure superficially similar to the eukaryote cell plus nucleus."},"keywords":{"sv":"Östersjö- och Östeuropaforskning","en":"Baltic and East European studies"},"project_id":"A086-2007_OSS","identifier_short":"A086-2007","local_ids":{"sh":["1169/42/2007:17"]},"dates":{"start_date":"2008-01-01","end_date":"2010-12-31"},"organizations":[{"funding":[{"_id":7,"id":"802400-4155","sv":"Östersjöstiftelsen","en":"The Foundation for Baltic and East European Studies"}]},{"coordinating":[{"_id":481,"id":"202100-4896","sv":"Södertörns högskola","en":"Södertörn University"}]}],"people":[{"project_leaders":[{"_id":"authority-person:309","orcid":"0000-0002-5802-5126","name":"Sjöling, Sara","role":"principal_investigator","affiliation":[{"_id":7470,"sv":"Miljövetenskap","en":"Environmental science","parent":[{"_id":486,"sv":"Institutionen för livsvetenskaper","en":"School of Life Sciences","parent":[{"_id":481,"sv":"Södertörns högskola","en":"Södertörn University"}]}]}]}]},{"other_personnel":[{"orcid":"0000-0001-9940-2824","name":"Pool, Anthony","role":"co_investigator","affiliation":[{"_id":504,"id":"202100-3062","sv":"Stockholms universitet","en":"Stockholm University"}]},{"_id":"authority-person:956","name":"Thureborn, Petter","role":"co_investigator","affiliation":[{"_id":7470,"sv":"Miljövetenskap","en":"Environmental science","parent":[{"_id":486,"sv":"Institutionen för livsvetenskaper","en":"School of Life Sciences","parent":[{"_id":481,"id":"202100-4896","sv":"Södertörns högskola","en":"Södertörn University"}]}]}]}]}],"tags":[{"_id":11550,"id":"10602","sv":"Biokemi och molekylärbiologi","en":"Biochemistry and Molecular Biology"}],"titles":{"en":"Anaerobic ammonia oxidation (anamox): a proposed missing piece in the Baltic Sea nitrogen cycle"},"total_funding":"2163630","type_of_awards":{"sv":"Projektbidrag","en":"Project grant"},"publications":[{"id":"diva2:1153831","type":"article-journal","status":"Published","issued":{"date-parts":[[2016]]},"title":"Livet i havets djup","language":"swe","author":[{"family":"Sjöling","given":"Sara","ORCID":"0000-0002-5802-5126","localId":"SHSASG","affiliation":[{"id":"11837","name":"Södertörns högskola, Miljövetenskap"}]},{"family":"Thureborn","given":"Petter","localId":"shprtn07","affiliation":[{"id":"11837","name":"Södertörns högskola, Miljövetenskap"}]}],"NBN":"urn:nbn:se:sh:diva-33653","localId":"1169/42/2007:17","issue":"2","page":"16-18","container-title":"HavsUtsikt- Om havsmiljön och Svensk havsforskning","ISSN":"1104-0513","keyword":"mikrobiell ekologi; Landsortsdjupet; samhälle; ekologiska interaktioner; havsbotten","published":[{"raw":"2017-10-31T15:40:00.000+01:00"}],"created":[{"raw":"2017-10-31T15:40:02.527+01:00"}],"updated":[{"raw":"2025-10-07T21:44:18.359+02:00"}],"URL":"https://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-33653"},{"id":"diva2:974622","type":"thesis","genre":"PhD dissertation","issued":{"date-parts":[[2016]]},"title":"Microbial Ecosystem Functions Along the Steep Oxygen Gradient of the Landsort Deep, Baltic Sea","language":"eng","author":[{"family":"Thureborn","given":"Petter","localId":"shprtn07","affiliation":[{"id":"11837","name":"Södertörns högskola, Miljövetenskap"}]}],"supervisor":[{"family":"Sjöling","given":"Sara","affiliation":[{"id":"11837","name":"Södertörns högskola, Miljövetenskap"}]},{"family":"Grahn","given":"Mats","affiliation":[{"id":"11837","name":"Södertörns högskola, Miljövetenskap"}]}],"opponent":[{"family":"Labrenz","given":"Matthias","affiliation":[{"name":"Leibniz-Institute for Baltic Sea Research (IOW), Rostock, Germany"}]}],"abstract":"Through complex metabolic interactions aquatic microbial life is essential as a driver of ecosystem functions and hence a prerequisite for sustaining plant and animal life in the sea and on Earth. Despite its ecological importance, infor­mation on the complexity of microbial functions and how these are related to environmental conditions is limited. Due to climate change and eutrophication, marine areas facing oxygen depletion are increasing and predicted to continue to do so in the future. Vertically steep oxygen gradients are particularly pronoun­ced in the Baltic Sea. In this thesis, therefore, the ecosystem functions of micro­bial communities were investigated, using metagenomics, to understand how they were distributed along the steep oxygen gradient at the Landsort Deep, the deepest point of the Baltic Sea. Furthermore, microbial communities from the Lands­ort Deep transect were compared to microbial communities of other marine environments to establish whether the environment at this site resulted in a characteristic community. To reveal what microbial community functions and taxa were active in the anoxic sediment a metatranscriptomic approach was used. Results showed a marked effect of the coupled environmental parameters dissolved oxygen, salinity and temperature on distribution of taxa and par­ti­cularly community functions. Microbial communities showed functional capa­cities consistent with a copiotrophic life-style dependent on organic ma­terial sinking through the water column. The eutrophic condition with high organic load was further reflected in the metatranscriptome of the anoxic sedi­ment com­munity, which indicated active carbon mineralisation through ana­erobic hetero­trophic-autotrophic community synergism. New putative linkages between nitro­gen and- sulphur metabolisms were identified at anoxic depths. Further­more, viable Cyanobacteria in the anoxic sediment was evident from the tran­script analyses as another reflection of marine snow. High abundance and expres­­sion of integron integrases were identified as a charac­teristic feature of the Lands­ort Deep communities, and may provide these communities with a mech­an­ism for short-term-adaptation to environmental change. In summary, this thesis clearly documents what impact eutrophication and oxygen depletion have on microbial community functions. Furthermore, it specifically advances the mechanistic insight into microbial processes in anoxic deep-water sediment at both genomic and transcriptional level. Given the predicted progress of oxygen depletion in marine and brackish environments, this work advances information necessary to estimate effects on marine and in particular brackish ecosystem functions where anoxic conditions prevail.","ISBN":"978-91-87843-58-7","NBN":"urn:nbn:se:sh:diva-30910","localId":"1169/42/2007:17","number-of-pages":"63","collection-title":"Södertörn Doctoral Dissertations","collection-number":"125","keyword":"microbial ecology; ecosystem functions; microbial community; bacteria; archaea; metagenomics; metatranscriptomics; oxygen gradient; hypoxia; sediment; Baltic Sea","publisher-place":"Huddinge","publisher":"Södertörns högskola","published":[{"raw":"2016-10-14T08:11:00.000+02:00"}],"created":[{"raw":"2016-09-27T10:31:01.753+02:00"}],"updated":[{"raw":"2025-10-07T09:10:56.393+02:00"}],"URL":"https://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-30910"},{"id":"diva2:900970","type":"article-journal","status":"Published","issued":{"date-parts":[[2016]]},"title":"Reconstructing ecosystem functions of the active microbial community of the Baltic Sea oxygen depleted sediments","language":"eng","author":[{"family":"Thureborn","given":"Petter","localId":"shprtn07","affiliation":[{"id":"11837","name":"Södertörns högskola, Miljövetenskap"}]},{"family":"Franzetti","given":"Andrea","affiliation":[{"name":"University of Milano-Bicocca, Milano, Italy"},{"id":"11831","name":"Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik"}]},{"family":"Lundin","given":"Daniel","affiliation":[{"name":"Science for Life Laboratories / Linnéuniversitetet"}]},{"family":"Sjöling","given":"Sara","ORCID":"0000-0002-5802-5126","localId":"SHSASG","affiliation":[{"id":"11832","name":"Södertörns högskola, Biologi"}]}],"abstract":"Baltic Sea deep water and sediments hold one of the largest anthropogenically induced hypoxic areas in the world. High nutrient input and low water exchange result in eutrophication and oxygen depletion below the halocline. As a consequence at Landsort Deep, the deepest point of the Baltic Sea, anoxia in the sediments has been a persistent condition over the past decades. Given that microbial communities are drivers of essential ecosystem functions we investigated the microbial community metabolisms and functions of oxygen depleted Landsort Deep sediments by metatranscriptomics. Results show substantial expression of genes involved in protein metabolism demonstrating that the Landsort Deep sediment microbial community is active. Identified expressed gene suites of metabolic pathways with importance for carbon transformation including fermentation, dissimilatory sulphate reduction and methanogenesis were identified. The presence of transcripts for these metabolic processes suggests a potential for heterotrophic-autotrophic community synergism and indicates active mineralisation of the organic matter deposited at the sediment as a consequence of the eutrophication process. Furthermore, cyanobacteria, probably deposited from the water column, are transcriptionally active in the anoxic sediment at this depth. Results also reveal high abundance of transcripts encoding integron integrases. These results provide insight into the activity of the microbial community of the anoxic sediment at the deepest point of the Baltic Sea and its possible role in ecosystem functioning.","DOI":"10.7717/peerj.1593","PMID":"26823996","ScopusId":"2-s2.0-84955558214","NBN":"urn:nbn:se:sh:diva-29454","volume":"4","number":"e1593","container-title":"PeerJ","ISSN":"2167-8359","published":[{"raw":"2016-02-05T15:02:00.000+01:00"}],"created":[{"raw":"2016-02-05T12:48:34.743+01:00"}],"updated":[{"raw":"2025-10-07T09:47:34.286+02:00"}],"URL":"https://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-29454"},{"id":"diva2:659263","type":"article-journal","status":"Published","issued":{"date-parts":[[2013]]},"title":"A Metagenomics Transect into the Deepest Point of the Baltic Sea Reveals Clear Stratification of Microbial Functional Capacities","language":"eng","author":[{"family":"Thureborn","given":"Petter","localId":"shprtn07","affiliation":[{"id":"11837","name":"Södertörns högskola, Miljövetenskap"},{"name":"Stockholm University"}]},{"family":"Lundin","given":"Daniel","localId":"shdlln10","affiliation":[{"name":"KTH & Stockholm University"},{"id":"11831","name":"Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik"}]},{"family":"Plathan","given":"Josefin","affiliation":[{"name":"Stockholm University"}]},{"family":"Poole","given":"Anthony M","affiliation":[{"name":"School of Biological Sciences, University of Canterbury, Christchurch, New Zealand"}]},{"family":"Sjöberg","given":"Britt-Marie","affiliation":[{"name":"Stockholm University"}]},{"family":"Sjöling","given":"Sara","ORCID":"0000-0002-5802-5126","localId":"SHSASG","affiliation":[{"id":"11837","name":"Södertörns högskola, Miljövetenskap"}]}],"abstract":"The Baltic Sea is characterized by hyposaline surface waters, hypoxic and anoxic deep waters and sediments. These conditions, which in turn lead to a steep oxygen gradient, are particularly evident at Landsort Deep in the Baltic Proper. Given these substantial differences in environmental parameters at Landsort Deep, we performed a metagenomic census spanning surface to sediment to establish whether the microbial communities at this site are as stratified as the physical environment. We report strong stratification across a depth transect for both functional capacity and taxonomic affiliation, with functional capacity corresponding most closely to key environmental parameters of oxygen, salinity and temperature.We report similarities in functional capacity between the hypoxic community and hadal zone communities, underscoring the substantial degree of eutrophication in the Baltic Proper. Reconstruction of the nitrogen cycle at Landsort deep shows potential for syntrophy between archaeal ammonium oxidizers and bacterial denitrification at anoxic depths, while anaerobic ammonium oxidation genes are absent, despite substantial ammonium levels below the chemocline. Our census also reveals enrichment in genetic prerequisites for a copiotrophic lifestyle and resistance mechanisms reflecting adaptation to prevalent eutrophic conditions and the accumulation of environmental pollutants resulting from ongoing anthropogenic pressures in the Baltic Sea.","DOI":"10.1371/journal.pone.0074983","PMID":"24086414","ScopusId":"2-s2.0-84884517639","NBN":"urn:nbn:se:sh:diva-20021","localId":"1169/42/2007:17","issue":"9","volume":"8","number":"e74983","container-title":"PLOS ONE","ISSN":"1932-6203","keyword":"miljömikrobiologi; metagenomik; ekosystemfunktioner; eutrofiering; Östersjön; sediment","published":[{"raw":"2013-10-24T15:40:00.000+02:00"}],"created":[{"raw":"2013-10-24T15:40:46.223+02:00"}],"updated":[{"raw":"2025-10-07T11:23:56.567+02:00"}],"URL":"https://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-20021"}],"links":[{"type":"pid","link":"https://su.diva-portal.org/smash/api/project/swecris/project:1824"}]}]