|Title||Ferromanganese concretion bottoms as habitats and a renewable resource in the Baltic Sea|
|Download||Download (whole publication) |
|Author||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; by Todd, B J; Brown, C J; Lacharité, M; Gazzola, V; McCormack, E; Geological Survey of Canada, Open File 8295, 2017 p. 68,
https://doi.org/10.4095/305876 (Open Access)|
|Publisher||Natural Resources Canada|
|Meeting||2017 GeoHab: Marine Geological and Biological Habitat Mapping; Dartmouth, NS; CA; May 1-4, 2017|
|Related||This publication is contained in Todd, B J; Brown, C J;
Lacharité, M; Gazzola, V; McCormack, E; (2017). Program and abstracts: 2017 GeoHab Conference, Dartmouth, Nova Scotia, Canada, Geological Survey of Canada, Open File 8295|
|Lat/Long WENS|| 10.0000 30.5000 66.0000 53.7500|
|Subjects||economic geology; marine geology; surficial geology/geomorphology; environmental geology; mapping techniques; oceanography; marine environments; conservation; marine organisms; marine ecology; resource
management; biological communities; environmental studies; ecosystems; marine sediments; silts; clays; glacial deposits; postglacial deposits; mineral potential; mineral deposits; iron; manganese; phosphorus; nodules; manganese nodules; iron
concretions, manganese; pollutants; grab samples; core samples; photography; benthos; bottom currents; erosion; reefs; geological mapping; geological mapping techniques; biology; habitat mapping; habitat conservation; habitat management; high
latitude mapping; renewable resources; rare earth elements; marine spatial planning|
|Program||Offshore Geoscience, Ocean Management Geoscience|
|Released||2017 09 26|
|Abstract||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.