Biological results Introduction to the underwater nature of the northern Bothnian Bay

• Low salinity • Low salinity, huge river runoff – many freshwater species, no true marine species • Humic dark brown water (low light penetration), large catchment area with bogs and mires – vegetation only in very shallow water (0-7 m depth) • Shallow – large shallow coastal areas and almost no vegetation zones Ulkomatala NE, Simo

0 20 40 60 80 100 120 0 -1 47 m 19 m 6 m 107 m -2 4 m 40 % 120-300 cm boulders 7 m -3 100 % sand 10 % 60-120 cm boulders 30 % 120-300 cm boulders 50 % sand 30 % 60-120 cm boulders -4 sed 1 1 % 10-60 cm stones sed 0 39 % sand -5 sed 1 Syvyyvs Syvyyvs (m) -6 0 m 0,5 m H = hiekka -7 30 % 120-300 cm boulders K = kivi 20 % 60-120 cm boulders -8 L = lohkare 40 % 10-60 cm stones 10 % 6-10 cm pebbles

Aegagrophila linnaei

Gastropoda sp.

Metsähallitus/Luontopalvelut, Johanna Kantanen Gastropoda sp. Fissidens fontanus • Ice-cover half a year • No tide, but very large water level changes because of winds and air pressure (up to 2-3 meters in a few days) Normal water level +150 cm • P is the limiting nutrient, not N – Bothnian Bay is more like an oligotrophic lake than a eutropich sea Most of the endangered aquatic species of the Baltic Sea are in the north Bothnian Bay

Sweden Finland

Vascular plant species 114 116

genuses 9 9

Charophytes 10 9

Water moss species 16 22

Algae + cyanobacteria 22 27

Total 162 174

Sweden Finland Vascular plant species 114 116 genuses 9 9 Charophytes 10 9 Water moss species 16 22 Algae + cyanobacteria 22 27 Total no of species 162 174 Elodea nuttallii – alien invasive species Hippuris tetraphylla (VU in Finland, CR in Sweden) Chara braunii (VU in Finland, VU in Sweden) Alisma wahlenbergii (VU in Finland, VU in Sweden) Probability of finding Alisma wahlenbergii High

Low

Accumulation of water moss species in the northern Bothnian Bay, Finland 25

20

15 species

10 of of

5 Number

0 1974 1994 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2018 2019 Year

Mud and sand flats

Sweden Finland

• Many endangered aquatic plant species • Important feeding areas for migrating birds • Many human pressures (dredging)

Tidal mudflats 1140 Digitized mudflats

Round goby/svartmunnad smörbult/mustatäplätokko (Neogobius melanostomus) outside Oulu

Hårig strimbock/meriuposkuoriainen (Macroplea pubipennis) in Sweden MOSAIC – Framework for nature value assessment in the marine environment

Value based upon four criteria: - Life cycle importance - Threat status - Contribution to biodiversity - Ecological function

Nature value maps