| Titre | Ferromanganese concretion bottoms as habitats and a renewable resource in the Baltic Sea |
| Télécharger | Téléchargement (publication entière) |
| Auteur | Kotilainen, A T; Kaskela, A M; Alanen, U; Kiviluoto, S; Kontula, T; Kostamo, K; Kurvinen, L; Sahla, M; Sippo, A; Virtanen, E |
| Source | Program and abstracts: 2017 GeoHab Conference, Dartmouth, Nova Scotia, Canada; par Todd, B J; Brown, C J; Lacharité, M; Gazzola, V; McCormack, E; Commission géologique du Canada, Dossier public 8295,
2017 p. 68, https://doi.org/10.4095/305876 (Accès ouvert) |
| Liens | GeoHab 2017
|
| Année | 2017 |
| Éditeur | Ressources naturelles Canada |
| Réunion | 2017 GeoHab: Marine Geological and Biological Habitat Mapping; Dartmouth, NS; CA; mai 1-4, 2017 |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/305876 |
| Media | en ligne; numérique |
| Référence reliée | Cette publication est contenue dans Todd, B J;
Brown, C J; Lacharité, M; Gazzola, V; McCormack, E; (2017). Program and abstracts: 2017 GeoHab Conference, Dartmouth, Nova Scotia, Canada, Commission géologique du Canada, Dossier public 8295 |
| Formats | pdf |
| Lat/Long OENS | 10.0000 30.5000 66.0000 53.7500 |
| Sujets | techniques de cartographie; océanographie; milieux marins; conservation; organismes marins; écologie marine; gestion des ressources; peuplements biologiques; etudes de l'environnement; écosystèmes;
sédiments marins; silts; argiles; dépôts glaciaires; dépôts postglaciaires; potentiel minier; gisements minéraux; fer; manganèse; phosphore; nodules; nodules de manganèse; concrétions de fer, manganèse; substances polluantes; échantillons prélevés au
hasard; échantillons carrotés; photographie; benthos; courants de fond; érosion; récifs; biologie; ressources renouvelables; géologie économique; géologie marine; géologie des dépôts meubles/géomorphologie; géologie de l'environnement |
| Programme | Géoscience de la gestion des océans, Géoscience en mer |
| Diffusé | 2017 09 26 |
| Résumé | (disponible en anglais seulement)
Ferromanganese (FeMn) concretions, also called FeMn nodules or polymetallic nodules, are iron-manganese-rich mineral precipitates on the seabed. Those
concretions are found in deep waters (e.g. the Pacific Ocean) but also in shallow seas like in the Baltic Sea. FeMn concretions are formed on the seabed by natural geochemical processes, catalyzed by micro-organisms, e.g. archaea and bacteria. These
supposedly renewable resources, FeMn deposits, have well known economic importance. They contain the high concentrations of iron, manganese, phosphorous but also rare earth elements and environmental pollutants. However their role e.g. in the
internal loading of nutrients and their ecological significance is still relatively poorly known.
Here we present FeMn concretion data from the Finnish waters of the Baltic Sea. The data has been collected over the past decades in the national
marine geological mapping program of the Geological Survey of Finland (GTK) (1984-2016) and in the Finnish Inventory Program for the Underwater Marine Environment (VELMU) (2005-2015). The data include nodule observations from nearly 300 sediment
samples (e.g. box corer and van Veen grab samples), 7000 video observations/points and over 70 scuba dives.
Different types of FeMn -concretions (e.g. spheroidal, discoidal, irregular and crusts/plates) were found at the seafloor with water
depths between 1-75 metres. Also the size of the concretions varied from small millimetre scale spheroidal nodules to large metre scale plates. FeMn concretions occurred in all studied sea areas, from the eastern Gulf of Finland, up north to the
Bothnian Bay. However, concretion fields/sites that form a HELCOM HUB-class "Baltic bottoms with at least 90% coverage of FeMn concretions" type habitat occurred only in the Gulf of Finland and the Archipelago Sea. Sediment sample data show that FeMn
concretions (1-3 cm thick layer) often cover silty clay (glacial and postglacial) seabed substrates.
FeMn concretions increase the microscale seabed heterogeneity (geodiversity) by forming relatively hard substrate on the predominantly soft
seafloor sediment. Concretions provide a 3D environment and hard physical structures, and support benthic communities, probably increasing biodiversity. In addition, concretion fields and crusts can protect the seafloor from erosion by near-bottom
currents. It is likely that these mineral deposits occurring in the Baltic Sea form an EU Habitats Directive habitat 'Biogenic reef', of which a representative part should be protected according to EU legislation.
Ferromanganese concretions could
also provide future mineral potential. However, the sustainable utilization of these marine resources and the need for marine environment protection pose great challenges for the development of ecosystem-based maritime spatial planning processes and
efficient Blue Growth.
This work is a part of the SmartSea project that is funded by the Strategic Research Council of the Academy of Finland, grant No: 292 985, and the assessment of marine habitat types (LuTU-Itämeri) that will be carried out
2016-2017 in a group of national experts from the universities, research institutes and authorities. |
| GEOSCAN ID | 305876 |
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