tiistai 19. syyskuuta 2023

A summer with Metsähallitus

Mapping the seabed along the shores from Vaasa to Tornio and back

Actors and conditions

Henkilö SUP-laudalla
The author mounting a stand-up paddle board (SUP), our main transport device on the site. Photo: Saara Luukkonen / Metsähallitus

The core team:

Neljä henkilöä kirkon edessä
The Team (from left to right): Saara Luukkonen, Erika von Essen, Essi Keskinen, and Rupert Simon. Photo: Essi Keskinen / Metsähallitus

We had an ambitious plan; hence we were working in (almost) any weather.

Vesipisaroita tippuu veden pinnalle

Example for weather: Rain dance (Nimbus aquaticus). Photo: Rupert Simon / Metsähallitus

Henkilö SUP-laudalla sateessa

A modern survival suit protects Essi from the conditions. Photo: Rupert Simon / Metsähallitus

Ilmaversoisen vesikasvin kukinto

Butomus umbellatus needs no suit. It apparently likes water coming from all sides. Photo: Rupert Simon / Metsähallitus

Kelluslehtinen vesikasvi
Also, Nuphar lutea, the yellow waterlily, flourishes in wetlands. Photo: Rupert Simon / Metsähallitus
Kelluslehtinen vesikasvi
Nymphea alba, the white waterlily is even more commonly encountered. Photo: Rupert Simon / Metsähallitus

Henkilö SUP-laudalla
Elin Vide joined the team for a couple of days as interim. Here, she is struggling with the elements. Photo: Rupert Simon / Metsähallitus

Henkilö istuu veneessä
On a calmer day, Saara uses the time on the boat for transferring data into the electronic system. Photo: Rupert Simon / Metsähallitus

Henkilö SUP-laudalla
Erika on a lucky day with sunshine. Photo: Rupert Simon / Metsähallitus

Henkilö meloo SUP-laudalla horisonttiin

Saara faces the stormclouds. Photo: Rupert Simon / Metsähallitus

In deeper waters, we needed to deploy divers. Occasionally, the vegetation was so dense that the line and diver got entangled.

Henkilö SUP-laudalla

Erika sorts out the line from the surface. Photo: Rupert Simon / Metsähallitus

Henkilö sukelluspuvussa
Essi is back - full of unintended samples. Photo: Rupert Simon / Metsähallitus

Chronology of events

Week 1+2 at Merenkurkku (The Quark)

On Monday, 3rd July, I started off for my first field assignment in Ostrobothnia. The water of the northern parts of Gulf of Bothnia has with 2-4% w/w the lowest salt content of the Baltic Sea. Target areas were small lagoons - called “flada”. These fladas are partly closed and have a restricted exchange of water with the main water body. This restriction results in an even more reduced content of salt in the lagoon than in the Bothnian Bay itself.

Henkilö pakettiauton edessä
A small transporter (nickname “Paku”) is carrying our equipment and ourselves. Erika introduces me to the work. Photo: Rupert Simon / Metsähallitus

Merenrantaa ja järviruokoja
Being in the wild: The first flada “Bulten”. Photo: Rupert Simon / Metsähallitus

Sudenkorento kuusenoksalla
A dragon fly waiting for the rain to end. According to the app Seek: Aeshna grandis. Photo: Rupert Simon / Metsähallitus

We had our basecamp at the old military base in Sommarö on Replot. The area is now managed by Metsähallitus and can be visited. Veterans have arranged for the installation of a memorial.

Linnakkeen muistomerkki
The memorial is representing the ugly side of Homo sapiens. Photo: Rupert Simon / Metsähallitus
Sinisorsaperhe metsän reunassa
Family of Anas platyrhynchos.  Photo: Rupert Simon / Metsähallitus

Ahomansikan versoja
Mansikka or Fragaria vesca (according to Seek). Photo: Rupert Simon / Metsähallitus

Usual suspects

In the field, we find certain species again and again. Here comes a photographic list of usual suspects. The first one in the row belongs to the green algae.

Näkinpartaislevä petrimaljalla
A close-up of Chara aspera. Photo: Rupert Simon / Metsähallitus

Näkinpartaisleviä pohjassa
Sunlight pattern on a soft bottom with Chara aspera. Photo: Rupert Simon / Metsähallitus
Näkinpartaisleviä kivien välissä
A bush of Chara aspera between large stones. The plants are covered by sediment, legacy of a windy time. Looking closely, we can identify the characteristic small red or orange gametes. Photo: Rupert Simon / Metsähallitus

Light plays with the undulated water surface and creates these magical views of the underwater landscapes. Here now clearly visible the red heads of Chara tomentosa between other aquatic species.

Näkinpartaisleviä veden alla
Sunlight pattern on a field dominated by another common algae, the red headed Chara tomentosa. Photo: Rupert Simon / Metsähallitus

Näkinpartaisleviä veden alla kivien vieressä
A closer look to the assemblage. Chara tomentosa in scattered company of another Chara spp. Photo: Rupert Simon / Metsähallitus

Näkinpartaisleviä veden alla
While the larger Chara tomentosa is still clearly visible, this spot seems rather dominated by Chara aspera. Photo: Rupert Simon / Metsähallitus

Ahvenia ja näkinpartaisleviä veden alla
Perches (Perca fluviatilis) patrolling the area. What is this big thing there with the camera? Photo: Rupert Simon / Metsähallitus

To make the life more complicated, there are things growing on the plants (epiphytic) and rocks (epilithic). This time, we focus on the animals:

Polyyppeja vesikasvin pinnalla
Freshwater polyps (Hydra vulgaris) on ahvenvita (Potamogeton perfoliatus). Photo: Rupert Simon / Metsähallitus

Polyyppeja vesikasvin pinnalla
Close-up on freshwater polyps (Hydra vulgaris) on ahvenvita (Potamogeton perfoliatus). Photo: Rupert Simon / Metsähallitus

Polyyppeja kiven pinnalla
Freshwater polyp Hydra vulgaris colony on a rock (epilithic). Photo: Rupert Simon / Metsähallitus

With the next species on the list, we move from algae to vascular plants. Vascular plants possess in contrast to algae - and as indicated by the name - a system of tubes including roots for the transport of nutrients and products throughout the organism.

Vesikasveja ja näkinpartaisleviä veden alla
Outcompeting the Chara spp by size: Stuckenia pectinata. Photo: Rupert Simon / Metsähallitus

Kukkiva uposlehtinen vesikasvi veden alla
Stuckenia pectinata growing a flower pod covered with some epiphytic algae. Photo: Rupert Simon / Metsähallitus
Vesikasvin kukinto
Close-up of the flower (Stuckenia pectinata). Photo: Rupert Simon / Metsähallitus

Another very common species belongs to the emerging plants.

Ruovikko rantavedessä ja metsän takana tuulivoimaloita
Phragmites australis, is a cosmopolitan. The very sturdy common reed has been used by humans in building roof tops. Photo: Rupert Simon / Metsähallitus

Järviruo'on kukinto
The flower of Phragmites australis resembles a paint brush or a bird’s plume feather. We deal with a wetland grass. Photo: Rupert Simon / Metsähallitus

Järviruokojen varsia ja näkinpartaisleviä veden alla
When looking at a dense patch of Phragmites australis, it seems to be very dense.  The underwater picture reveals the spacing between the stems forming an underwater forest. This is a place for juvenile fish, here a school of Perca fluviatilis, to grow up to maturity. Fishermen know that pike (Esox lucius) is preying on them here, hence it’s a good place for fishing. Photo: Rupert Simon / Metsähallitus

Weekend at Merenkurkku (The Quark)

As we all know, the Finnish floor is rising. This is especially visible in the Quark area (FI:  Merenkurkku). Here, the glaciers formed the land and over generations, harbours have landed and needed to move following the water retreat. The area around Svedjehamn is a visible example of this and part of the UNESCO world heritage site. 

Henkilö puistossa
Illustration of the land rise meter by meter or century by century at the maritime museum in Vaasa. Each of the spheres marks the location of the shoreline at the full century. The series goes back from 1900 to 1500 (from front to back). Dalia gives you the reference of the scale. Photo: Rupert Simon / Metsähallitus

Merenlahti ja satama tornista kuvattuna
Land’s End at Svedjehamn seen from the watch tower “Saltkaret”. Photo: Rupert Simon / Metsähallitus

Merenlahti näkötornista kuvattuna
The area shows lines of gravel left behind long ago by the retreating glaciers. The pattern forms almost rectangular lagoons. Photo: Rupert Simon / Metsähallitus
Merenlahti näkötornista kuvattuna
Looking into the sun in the north-west. Behind the horizon lies Sweden. The western side of The Quark area contrast to the shallow beaches of the eastern Finnish shores. There the same glaciers have formed a fjord-like landscape. The Swedish high coast therefore belongs to the natural phenomenon and is included in the UNESCO world heritage site. Photo: Rupert Simon / Metsähallitus

Venevajoja ja veneitä pienvenesatamassa
Back in Swedjehamn, we have a look at historical boat houses and (not yet historical) boats. Photo: Rupert Simon / Metsähallitus

Being the longest bridge of Finland, the Replot bridge is by itself already a tourist attraction. This is boosted by the info centre at the west end telling the story of the land rise and the UNESCO heritage site.

Saareen johtava korkea silta
The Replot Bridge seen from east to west on 15 July 2023 at 11:45. Photo: Rupert Simon / Metsähallitus
Auringonlasku sillalta kuvattuna
The Replot Bridge on 15 July 2023 at 22:05. The spectacular sunsets are famous, and it pays off to stay late. With a free view North, this must be a popular spot during Midsummer night. Photo: Rupert Simon / Metsähallitus

Having lunch. The black headed gull Chroicocephalus ridibundus is of the same opinion as me. Good food shall never be left alone. Here comes the result:

Kolme lokkia lentämässä ravintolapöytää kohti
Three incoming Chroicocephalus ridibundus targeting leftovers. Photo: Rupert Simon / Metsähallitus

Lokki ravintolapöydän yläpuolella suussaan ranskanperunoita
Got French fries! Impressive how they pick-up the “prey” hardly touching the dishes. If we could dive like that!!! Photo: Rupert Simon / Metsähallitus

Kolme lokkia aidalla
Here are clearly the suspects. They couldn’t appear more innocent than they do: “Wasn’t us. We? What? Never, not in our wildest dreams!” Photo: Rupert Simon / Metsähallitus

Week 3 + 4 at Merenkurkku (The Quark)

New week, new team member, new luck. Elin is joining as interim for a couple of days and more species emerge to join the list of usual suspects.

Kaksi henkilöä seisoo rannassa katsomassa karttaa SUP-lautojen ja laiturin vieressä
Erika and Elin discussing the course of action for this site. Photo: Rupert Simon / Metsähallitus

Kukkiva uposlehtinen vesikasvi ahvenvita vedessä
Potamogeton perfoliatus is one of the most common and most easily visible plants in the Finnish waters. The specimens look healthy and carry picturesque flower buds. Photo: Rupert Simon / Metsähallitus

Uposlehtinen vesikasvi, ahvenvita veden alla

Uposlehtinen vesikasvi, ahvenvita

Uposlehtinen vesikasvi, ahvenvita

The genus Potamogeton has obviously more members than just one.

Vesikasvi ja näkinpartaisleviä veden alla
Potamogedon crispus is resembling P. perfoliatus but distinguishes itself by undulated leaves. It was found less frequently these days. Still, we got this picture underwater. Photo: Rupert Simon / Metsähallitus

Vesikasvi vedessä
Here the same P. crispus from the surface. The undulated leaves are visible on the left while the flower buds are to the right. Photo: Rupert Simon / Metsähallitus

Another genus is Myriophyllum. These water milfoil are alike the common reed cosmopolitans with wide distribution.

Uposlehtisiä vesikasveja veden alla
Myriophyllum sibiricum as seen from the boat and picture taken under the surface. Photo: Rupert Simon / Metsähallitus

Uposlehtinen vesikasvi veden alla
The same species Myriophyllum sibiricum under water carrying some sedimentation in a close-up picture. Photo: Rupert Simon / Metsähallitus

Kukkiva uposlehtinen vesikasvi kädessä veden alla
Myriophyllum sibiricum with flower buds. Photo: Rupert Simon / Metsähallitus

Week 5

After mapping the Quark, we moved north to Tornio.

Veneitä retkisatamassa näkötornista kuvattuna
Perämeren Kansallispuisto from the watch tower. Our boat Maia lies behind the vessel used by the Sea Rescue Club “Meripelastajat”. Photo: Rupert Simon / Metsähallitus

Auringonlasku merellä
Sunset in the north taken at 21:48. Photo: Rupert Simon / Metsähallitus

Kolme SUP-lautailijaa merellä auringonlaskun aikaan
As the weather conditions were so favourable, and you never know, when this is going to change, we (or rather the girls) decided to still go for a flada during sunset. Photo: Rupert Simon / Metsähallitus
SUP-lautailija merellä auringonlaskussa
The last musketeer is coming back. Photo: Rupert Simon / Metsähallitus

Kivimuureja meren rannikolla
The weather was not so friendly in the next morning. As we anyway had to wait for the wind to calm down, we visited the south end of the island. Left over are historical stone walls used by fishermen as home during their stay. They would close the shelter on top using a sail. Photo: Rupert Simon / Metsähallitus

Pieni puinen museorakennus
A small hut from a later era serves now as a small exhibition place of donated items. Photo: Rupert Simon / Metsähallitus

Vanhoja kalaverkkoja ja muita museoesineitä vajassa
Collected items on display show fishing gear and more stuff used in daily life. Photo: Rupert Simon / Metsähallitus

Museoesineitä vajassa

Vanhan tulisijan jäänteet hirsiseinäisen huoneen nurkassa

Large rocks formed the foundation for a fireplace. Photo: Rupert Simon / Metsähallitus

To do something useful, we were investigating the beach under the wavelets.

Kolme henkilöä kahlaamassa meressä lähellä rantaa

Searching for gravel substrate. Photo: Rupert Simon / Metsähallitus

Irrallaan keijuvia vesikasveja kivien välissä
Finding Lemna trisulca growing between larger stones. Photo: Rupert Simon / Metsähallitus
Lähikuva vesikasveista kädellä
Close-up picture of Lemna trisulca for identification. Photo: Rupert Simon / Metsähallitus

Lampaita laiduntamassa merenrantaniityllä
A little further, grazing sheep maintain the vegetation of the landscape as it has been for centuries. This way they keep the cultural heritage intact. Photo: Rupert Simon / Metsähallitus

And again, as soon the wind calmed down, let’s go diving to see what is at the sea bottom!

Sukeltaja pinnalla ja taustalla vene
Erika ready to descent. Photo: Rupert Simon / Metsähallitus

Sukeltaja veden alla kirjoittamassa havaintolomakkeeseen
Erika recording observations – the classic! Photo: Rupert Simon / Metsähallitus

Vesisammalia lähikuvassa
Oxyrrhynchium speciosum with polyps (Hydra sp.). Photo: Rupert Simon / Metsähallitus

Narun päässä oleva kyltti, jossa on numero 40
Not much vegetation at the 40m label of the transect. Photo: Rupert Simon / Metsähallitus

Lähikuva sienieläimestä
Sponge (Ephydatia fluviatilis) as a side observation. Photo: Rupert Simon / Metsähallitus
Irtonaista kuollutta ainesta ja vesikasveja

Could this be an overgrown specimen of Najas marina? Photo: Rupert Simon / Metsähallitus

Polyyppeja kiinnittyneenä substraattiin
Water polyps, animals of the genus Hydra on a substrate. Photo: Rupert Simon / Metsähallitus

The time in Tornio is up and we are moving to Ii.

Henkilö ajamassa venettä
Rupert at the helm of the boat. Photo: Erika von Essen / Metsähallitus
Veneen keula sateessa
Looking out from the helm. In perhaps 50m visibility we are relying on our instruments. Photo: Rupert Simon / Metsähallitus

Maantie sateella
The sky after the rain on the way to Oulu for the weekend. Photo: Rupert Simon / Metsähallitus


Oulu. Town and river. One of the four largest towns at this northern latitude.

Pato ja sen alapuolinen koski
The Oulu River dam. When installed, it cut off the salmon migration into the Oulu River. Photo: Rupert Simon / Metsähallitus

Pato ja lohiportaat
The Oulu River dam and a fish ladder in the foreground on the left. The operator of the dam, Oulun Energia, stated in a recent brochure I found at their website that there was video evidence from 2019 for perch, bream, roach, pike, whitefish, trout, and salmon travelling up this bypass. Photo: Rupert Simon / Metsähallitus

Rantaan iskeytyvä aalto
The sea is giving away what is growing underneath her waves. Photo: Rupert Simon / Metsähallitus

Vesikasvi hiekalla
Et voila: Potamogeton perfoliatus - one of the usual suspects - shows up. Photo: Rupert Simon / Metsähallitus

Week 6

Week 6, we spend on Ulkokrunni at the Oulu University’s research station. Unfortunately, I left my camera in the car at the mainland, so I have only images I took with my phone.

Terävähuippuinen pookirakennus varvikon ja puiden keskellä
Historical landmark for seafaring called Pooki. This one dates to 1841. Photo: Rupert Simon / Metsähallitus

Henkilö saunarakennuksen terassilla
Living on an island without running water and limited access to electricity, the sauna visit became part of our daily ritual. Photo: Rupert Simon / Metsähallitus

Kompressori ja muuta rojua varastorakennuksen ja rantametsän edessä
Filling SCUBA tanks after a diving day may happen in a romantic scenery. Photo: Rupert Simon / Metsähallitus

Henkilö ja tavaroita pusikkoisessa rannassa, jossa on kaksi venettä
Packing the boat for moving to the shore of Ii. Then after repacking followed the transfer of equipment to our next station in Raahe.

Week 7

You cannot be in Raahe without seeing the oldest still existing diving suit of the world. I was so impressed that I forgot to take a picture. On the other hand, there are many taken already.

So, I give you a link to the website of the museum: https://raahenmuseo.fi/tietoa-museoista/wanha-herra. Look and see!

In Raahe, we stayed in the cottage of Meripelastajat and placed Maia next to Mursu IV, the boat of the diving club, properly named “Mursut”. The time at Raahe starts with windy weather.

Henkilö kahlaamassa meressä SUP-laudan vieressä
The first place offered wavy condition for doing the transect. Photo: Rupert Simon / Metsähallitus

Saareen menevä tie, jonka molemmin puolin vettä
If you don’t like the weather, just wait a bit. Hence, we found more friendly conditions at the second place. Photo: Rupert Simon / Metsähallitus

Sammakko rantavedessä
This is my realm (Rana temporalis). Photo: Rupert Simon / Metsähallitus

Kaksi henkilöä merellä SUP-laudoilla, etualalla ruovikkoa ja puita
The softstem bulrush (Schoenoplectus tabernaemontani) grouping behind a patch of common reed (Phragmites australis) in the foreground. Saara and Erika recording the vegetation along a transect. Photo: Rupert Simon / Metsähallitus
Kaisloja ja ruovikkoa
A bunch of Schoenoplectus tabernaemontani comes in the way of the board and stars in a close-up picture. Photo: Rupert Simon / Metsähallitus


Moving south to Kalajoki (also town and river).

Koskia joessa ja ympärillä rakennuksia
Kalajoki rapids. Photo: Rupert Simon / Metsähallitus

Silta ja koski joessa, takana puita ja rakennuksia
Kalajoki rapids and flower mill (red building in the back). The proportion of water used for machinery contrasts the situation in Oulu. Photo: Rupert Simon / Metsähallitus

The sandy beaches of Kalajoki are unique. They are known as “Hiekkasärkät”. Photo: Rupert Simon / Metsähallitus

Näkinpartaislevä kädellä lähikuvassa
A sample from the swimming beach. This looks like Chara aspera.
Lähikuva näkinpartaislevästä kädellä
At the rhizoids (the part growing in the sediment like roots), round, white bulbils are found. These are considered typical for Chara aspera.

Week 8

This week’s highlight was the visit to Maakalla where we had to take a transect for the Baltic Sea mapping program of Metsähallitus.

Meren keskellä sijaitseva saari, jossa sääasema ja muita rakennuksia
The weather station on Ulkokalla. A common saying is: “At Ulkokalla, they make the weather”. Photo: Rupert Simon / Metsähallitus

Näkymä metallilaiturilta saareen, jossa kalastajamökkejä
At the Maakalla guest harbour. Photo: Rupert Simon / Metsähallitus

Pieniä kalastajamökkejä saaressa
The guest harbour seen from the watch tower. Photo: Rupert Simon / Metsähallitus

Pieni puinen museorakennus
The Maakalla Museum

Vanha ankkuri seinällä museossa
Inside the museum: a historical anchor on display. Photo: Rupert Simon / Metsähallitus

Vanhoja poijuja seinällä museossa
Historical floaters for fishing nets. Photo: Rupert Simon / Metsähallitus

Vanha reki museossa
A historical sledge used for seal hunting on the ice. Photo: Rupert Simon / Metsähallitus

The island had up to 400 inhabitants and needed pastoral supervision. The island has until today its own local government and is ruled by the people.

Vanha puukirkko ja kalastajamökkejä saaressa
The church of Maakalla. Photo: Rupert Simon / Metsähallitus

Vanhan puukirkon penkkejä ja saarnatuoli
The church inside. The place got crowded when 400 souls were attending the service. Photo: Rupert Simon / Metsähallitus

Penkkejä käytävän molemmin puolin ja katosta roikkuva laivan pienoismalli vanhassa puukirkossa
View from the crossroad in the centre shows the size of the seemingly small building. Photo: Rupert Simon / Metsähallitus

Henkilö kirkon ovella
Closing after the visit is good practice of curtesy. Photo: Rupert Simon / Metsähallitus

The audit of our diving procedure.

Kolme henkilöä kävelemässä sataman viereisellä soratiellä
Here come the auditors for a visit. Photo: Rupert Simon / Metsähallitus

Seitsemän henkilöä veneessä
The audience is keen to learn everything about diving, the procedures, and the safety equipment. Photo: Rupert Simon / Metsähallitus


Now we are safely audited and considered safe enough to move to Kokkola. This would be the last but not the least station.

Kanava, venevajoja ja vene laiturissa
The old channel to the historical market, the heart of Kokkola, framed by historical boat houses. Photo: Rupert Simon / Metsähallitus

Peltikattoinen vanha puurakennus
The oldtimer on the block. Photo: Rupert Simon / Metsähallitus

Meren takana metsää ja kolme tuulivoimalaa auringonlaskussa
A modern way to generate electricity. The windmills in the sunset would have impressed Don Quijote. Photo: Rupert Simon / Metsähallitus

Vesikasvi vedessä
Still found a “new” species in the water, most probably Callitriche hermaphroditica. Photo: Rupert Simon / Metsähallitus
Vesikasvi kädellä lähikuvassa
Close-up photo for clarification: Callitriche hermaphroditica. Photo: Rupert Simon / Metsähallitus

Week 9

Kokkola was the challenge for navigation. The waters around the archipelago are shallow and seasoned well with rocks.

Kiviä ja ruovikkoa meressä
Shallow waters with an emerging island surrounded by rocks. Photo: Rupert Simon / Metsähallitus
Henkilö veneen keulassa kuljettaessa kanavaa pitkin
Typical environment for boating. Official minimum depth in such boat lanes was 1.2m. I read at some point only 0.9m on the echosounder’s display. We were occasionally holding our breath when travelling through these waters. Photo: Rupert Simon / Metsähallitus

Week 10

This week was used for cleaning and storing the gear, updating records, and writing reports, such as this blog.

Week 11 + 12

Well-deserved HOLIDAYS

Suomen lippu veneen perässä ja auringonlasku
Sailing during sunset. Photo: Rupert Simon / Metsähallitus

List of species encountered (not exhaustive)


Butomus umbellatus

Chara aspera

Chara tomentosa

Phragmites australis

Schoenoplectus lacustris

Schoenoplectus tabernaemontani

Zannichellia palustris

Lemna trisulca

Lysimachia thyrsiflora (semi-terrestrial)

Myriophyllum sibiricum

Myriophyllum spicatum

Najas marina

Nuphar lutea

Nymphaea alba

Potamogeton crispus

Potamogeton perfoliatus

Stuckenia pectinata


Anas platyrhynchos

Chroicocephalus ridibundus

Culex pipiens

Haemopis sanguisuga

Haliaeetus albicilla

Pentatoma rufipes

Vespula germanica


Boletus edulis