• Lithothamnion (Hapalidiales, Rhodophyta) in the changing Arctic and Subarctic: DNA sequencing of type and recent specimens provides a systematics foundation 

      Peña, Viviana; Bélanger, David; Gagnon, Patrick; Richards, Joseph L.; Gall, Line Le; Hughey, Jeffery R.; Saunders, Gary W.; Lindstrom, Sandra C.; Rinde, Eli; Husa, Vivian; Christie, Hartvig C; Fredriksen, Stein; Hall-Spencer, Jason M.; Steneck, Robert S.; Schoenrock, Kathryn M.; Gitmark, Janne Kim; Grefsrud, Ellen Sofie; Anglès d'Auriac, Marc; Legrand, Erwann; Grall, Jacques; Mumford, Thomas F.; Kamenos, Nicholas A.; Gabrielson, Paul W. (Peer reviewed; Journal article, 2021)
      Coralline red algae in the non-geniculate genera Clathromorphum, Phymatolithon and Lithothamnion are important benthic ecosystem engineers in the photic zone of the Arctic and Subarctic. In these regions, the systematics ...
    • Local flexibility in feeding behaviour and contrasting microhabitat use of an omnivore across latitudes 

      Leclerc, Jean-Charles; de Bettignies, Thibaut; de Bettignies, Florian; Christie, Hartvig C; Franco, João N; Leroux, Cédric; Davoult, Dominique; Pedersen, Morten F; Filbee-Dexter, Karen; Wernberg, Thomas (Peer reviewed; Journal article, 2021)
      As the environment is getting warmer and species are redistributed, consumers can be forced to adjust their interactions with available prey, and this could have cascading effects within food webs. To better understand the ...
    • Macrophytes as habitat for fish 

      Christie, Hartvig C; Andersen, Guri Sogn; Tveiten, Lise Ann; Moy, Frithjof Emil (Peer reviewed; Journal article, 2022)
      As different macrophyte habitats house different distributions of invertebrates, we questioned if differences in the composition of fish in these habitats also could be identified. Additionally, we addressed the question ...
    • Miljøoppfølging E136 Tresfjordbrua. Sluttrapport 

      Borgersen, Gunhild; Brkljacic, Marijana Stenrud; Gitmark, Janne Kim; Golmen, Lars Gunder; Kempa, Magdalena; Ledang, Anna Birgitta; Lømsland, Evy Rigmor; Christie, Hartvig C (NIVA-rapport;7201, Research report, 2017)
      Statens Vegvesen har ferdigstilt bru over Tresfjorden, en utbygging som også omfatter en sjøfylling. NIVA har utført miljøundersøkelser og modellberegninger av forholdene før og etter anleggsvirksomheten for å vurdere om ...
    • Naturtyper i Saltstraumen marine verneområde 

      Fagerli, Camilla With; Gundersen, Hege; Gitmark, Janne Kim; Staalstrøm, Andre; Christie, Hartvig C (NIVA-rapport;6841, Research report, 2015)
      Denne undersøkelsen rapporterer naturverdier i Saltstraumen marine verneområde basert på videoregistreringer langs 30 linjer (transekter). Det ble registrert 15 naturtyper (NiN) i området der hardbunn og særlig fast bunn ...
    • New microsatellite loci for the green sea urchin Strongylocentrotus droebachiensis using universal M13 labelled markers 

      Angles d'Auriac, Marc; Hobæk, Anders; Christie, Hartvig C; Gundersen, Hege; Fagerli, Camilla With; Haugstetter, Johannes; Norderhaug, Kjell Magnus (Journal article; Peer reviewed, 2014)
    • Optimizing the use of quicklime (CaO) for sea urchin management — A lab and field study 

      Strand, Hans Kristian; Christie, Hartvig C; Fagerli, Camilla With; Mengede, Martin; Moy, Frithjof Emil (Peer reviewed; Journal article, 2020)
      Mass blooms of sea urchins sometimes cause kelp forest collapses that can last for decades. Quicklime has historically been used to reverse those conditions, but the efficacy of liming has varied along latitudinal and ...
    • Predation mortality from ambush and cruising predators on newly-settled 0-group gadoids 

      Pedersen, Torstein; Strand, Hans Kristian; Christie, Hartvig C; Moy, Frithjof (Peer reviewed; Journal article, 2020)
      We investigated predation from an ambush predator (shorthorn sculpin) and two cruising predators (Atlantic cod and saithe) on bottom-settled 0-group cod and saithe juveniles in a fjord in northern Norway. Stomach contents ...
    • Predators of the destructive sea urchin grazer Strongylocentrotus droebachiensis on the Norwegian coast 

      Fagerli, Camilla With; Norderhaug, Kjell Magnus; Christie, Hartvig C; Pedersen, Morten Foldager; Fredriksen, Stein (Journal article; Peer reviewed, 2014)
      In central Norway, populations of the green sea urchin Strongylocentrotus droe-bachiensis are collapsing, but the factors controlling its population density have not yet been elucidated. Through field sampling, we identified ...
    • Regrowth of kelp after removal of sea urchins (Strongylocentrotus droebachiensis) 

      Carlsson, Pernilla Marianne; Christie, Hartvig C (NIVA-rapport;7431, Research report, 2019)
      With few natural predators, green sea urchins (Strongylocentrotus droebachiensis) have grown in numbers, grazed down large kelp forest areas in Northern Norway into urchin barrens. NIVA deployed three underwater cages ...
    • Shifts between sugar kelp and turf algae in Norway: regime shifts or flips between different opportunistic seaweed species? 

      Christie, Hartvig C; Andersen, Guri Sogn; Bekkby, Trine; Fagerli, Camilla With; Gitmark, Janne Kim; Gundersen, Hege; Rinde, Eli (Journal article; Peer reviewed, 2019)
      Around year 2000, sugar kelp (Saccharina latissima) forests were observed to disappear in southern parts of Norway, being replaced by mats of turf algae (i.e. filamentous ephemeral algae) loaded with sediments. About 80% ...
    • Synergism between cruising cod and ambush sculpin predators on 0-group gadoids is modified by daylight cycle and presence of aggressive wolffish 

      Strand, Hans Kristian; Pedersen, Torstein; Christie, Hartvig C; Moy, Frithjof Emil (Peer reviewed; Journal article, 2020)
      Shorthorn sculpin (Myoxocephalus scorpius) and large cod (300–400 g body weight) are important predators on newly settled 0-group cod (Gadus morhua) and saithe (Pollachius virens) in Porsangerfjorden in northern Norway. ...
    • Tallknusing av sukkertaredata 

      Gundersen, Hege; Norderhaug, Kjell Magnus; Christie, Hartvig C; Moy, Frithjof Emil; Hjermann, Dag Øystein; Vedal, Jens; Ledang, Anna Birgitta; Gitmark, Janne Kim; Walday, Mats (NIVA-rapport;6737, Research report, 2014)
      Norsk institutt for vannforskning (NIVA) og Havforskningsinstituttet (HI) har gjennomført prosjektet «Tallknusing av sukkertare-data», på oppdrag fra Miljødirektoratet. Gjennom prosjektet har tilgjengelige data som kan ...
    • The abundance of kelp is modified by the combined impact of depth, waves and currents 

      Bekkby, Trine; Smit, Cecilie; Gundersen, Hege; Rinde, Eli; Steen, Henning; Tveiten, Lise Ann; Gitmark, Janne Kim; Fredriksen, Stein; Albretsen, Jon; Christie, Hartvig C (Journal article; Peer reviewed, 2019)
      This study analyses the combined impact of two types of ocean water flow, wave exposure and ocean currents, on kelp Laminaria hyperborea abundance, taking other environmental co-variables into account. The dataset covers ...
    • Top-down release of mesopredatory fish is a weaker structuring driver of temperate rocky shore communities than bottom-up nutrient enrichment 

      Kraufvelin, Patrik; Christie, Hartvig C; Gitmark, Janne Kim (Peer reviewed; Journal article, 2020)
      Ecological impacts of top-down trophic cascades in combination with bottom-up nutrient enrichment are increasingly being reported. Such effects may be triggered by decline in the abundance and size of piscivore fish leading ...
    • Utbredelse og tilstand til en nasjonalt viktig ålegraseng i Slependrenna i Asker og Bærum kommune 

      Brkljacic, Marijana Stenrud; Rinde, Eli; Christie, Hartvig C (NIVA-rapport;7509, Research report, 2020)
      Observasjoner mai 2013 viste fravær av ålegras i den tidligere kartlagte nasjonalt viktige ålegrasenga i Slependrenna. På oppdrag fra Fylkesmannen i Oslo og Akershus har vi gjort oppfølgende undersøkelser for å observere ...
    • Utvikling av kartleggingsmetodikk og kriterier for lokalitetskvalitet for marine naturtyper. 

      Rinde, Eli; Moy, Siri Røang; Borgersen, Gunhild; Brkljacic, Marijana Stenrud; Fagerli, Camilla With; Gitmark, Janne Kim; Mjelde, Marit; Bekkby, Trine; Bjorbækmo, Marit Frederikke Markussen; Christie, Hartvig C; Kile, Maia Røst; Næss, Rita; Oug, Eivind; Tveiten, Lise Ann; Walday, Mats Gunnar (NIVA-rapport;7805-2022, Research report, 2022)
      Dette arbeidet er en videreføring av påbegynt arbeid fra 2020 og 2021 knyttet til kunnskap og metodeutvikling for kartlegging av marine naturtyper og for å kunne beskrive naturtypelokaliteters økologiske kvalitet. Arbeidet ...
    • Vurdering av spredning av partikler fra Aksla steinbrudd 

      Staalstrøm, Andre; Kristiansen, Trond; Christie, Hartvig C (NIVA-rapport;7160, Research report, 2017)
      Spredning av steinstøv fra planlagt utskipningskai ved Bårdvikneset i Frøysjøen er i dette prosjektet modellert med havmodellen ROMS og verktøyet OpenDrift som beregner partikkelbaner. Partikkelkonsentrasjon i vannmassene ...