The possibility to follow up the succession of microbial life in a virgin soil quite free from organic substances has been fascination. In 1972, five years after the eruptions ended on Surtsey, soil samples could still be gathered which did not show any evidence of microbial life.
It was not unexpected that free-living blue-green algae with the ability to use sun energy and the molecular nitrogen of the air for growth and development, were among the primary immigrants of Surtsey. The algae, which nowadays (1982) frequently occur on the island, are also found to live in associations with mosses.
evidence of biological nitrogen fixation on Surtsey was recorded in 1970, when
it was found in laboratory experiments that microorgnisms in Surtsey soils
showed the activity of nitrogenase, the enzyme which is necessary for all
biological nitrogen fixation. The organismsms involved were found to be
light-depended. By cultivation it was found that the nitrogenase activity was
derived from the blue-green algae Anabaena
It may be surprising that algal nitrogen fixation at a high level can be recorded in soils where blue-green are not visitble to the naked eye. Therefore, it must be incorrect when earlier research stated that blue-green algae are unimportant as primary colonisers of Surtsey, since one could not detect them...
A necessary condition for nitrogen fixation (nitrogenase activity) is moisture. Vast areas of Surtsey are therefore often unsuitable for nitrogen fixation and growth of nitrogen-fixing microorganisms. Samples from this area were analysed for occurence of living microorganisms in
Click on picture for larger view.
© c/o www.vulkaner.no
In fact, the nitrogen-fixing activities on Surtsey are well estabished and are of major importance for the nitrogen input and nitrogen economy during the primary ecological stage of development.
During the last decade the plants of Honkenya peploides have increased greatly in number on Surtsey. Many plants have been buried under sand drifts and new ones have arrived. These circumstances must result in accumulation of organic matter into the soil. Old roots are decomposed, and from living roots organic substances are exudated into the root environment.
text above is Based upon a report by Lars Eric Henriksson and Elisabet
Henriksson Institute of Physiological Botany,
Sandwort, Seabirds, and Surtsey
by Carla Helfferich
This article is provided as a public service by the
It was 1964.
Our guide, a long-time friend who worked as an engineer for the government of
have a great sense of humor. The fog was so thick we could barely see to the
sides of the road. I never did glimpse the newborn island rising from the
ways, it's remarkable that Surtsey is still around to interest anyone. The
frequent eruptions on and off Iceland kick up new little islands now and again,
but---like the two that have formed since Surtsey quit erupting in 1968---they
usually are soon washed and blown away. That happens partly because the
eruptions often contain much ash and little lava, and partly because the area
has weather that challenges even the
similar to an island in the
cases, "ecosystem" is as yet far too grand a word for the patches and
communities of organisms on Surtsey. The only plant that seems to be gaining
ground on the island's outer slopes is a tough sea sandwort, a flowering plant
that ranges around arctic shores even to
The sandwort patches are still few and far between. Thicker vegetation has grown up within the now quiet craters. Sheltered from the wind, mosses and their kindred form a thickening carpet over much of the once-bare lava. (Mosses, in fact, were the first plants to make a stand on Surtsey. A hundred or so species have tried to colonize the island, but they succumb to the weather wherever the wind can rip them from the gritty earth or rip the grit away from their roots.)
On Surtsey, life is most complex where sea and land interact. As a minor example, a species of small fly is one of the few animals to live full-time on the island; the flies feed on the marine algae growing on the shoreside rocks.
conspicuous are other animals now making Surtsey their home. Hundreds of
seabirds have moved in. Fulmars, kittiwakes, gulls, and guillemots can be found
in season on the
Land at the
base of the bird-inhabited cliffs harbors the richest vegetation, twenty-odd
species of vascular plants, mostly grasses. For now, the scientists report, it
is the only place on Surtsey where the vegetation looks like that elsewhere in
Rock and troll
years ago a submarine eruption off the south coast of
are being watched. A curious seal stares at the three of us, jumping with heavy
backpacks from the boat into the dinghy. Surtsey, the island of the terrible
giant of fire in Nordic mythology, rises ahead. Most of the shoreline is steep
cliffs, scoured by the surf. We grab the oars and row towards one uninviting
rocky stretch, a witness to the vast power of the
Wet and panting we clamber around the surf-beaten boulders and driftwood trunks that the winter storms have tossed far up on the island's shore and gaze up at the dun-coloured mountain of tuff (volcanic rock), towering over the centre of the island. Our shoes become grey with a mixture of ash and sand.
Small, circular patches of shoreline vegetation, clumps of lymegrass and colourful, lonely flowers soften the visage of the landscape. All of a sudden the sun finds a tear in the grey cloud fabric to pour down on us - cheerful white wagtails, snow buntings and wheatears go winging by and I get the feeling this is going to be a wonderful day.
Surtsey was born in a great submarine eruption 33 km south of the Icelandic coast, along an active fissure belt linked to the mid-Atlantic ridge. In November 1963, the earth's crust cracked open to send molten magma at a temperature of 1,150°C gushing up from the ocean floor. First to become aware of the eruption were Icelandic fishermen. Early in the morning of November 14, the sea suddenly became turbulent, the crews noticed a strange smell - like sulphur - and soon black smoke started to rise from the sea. The following day the first glimpse of Surtsey appeared above the waves. During the first months of the eruption the surf broke down the crater crust as quickly as it formed and flooded into the crater bowl. This caused a rapid cooling of the magma, forming fine tephra (fragments) which was spewed as high as 10 km up into the atmosphere.
Gradually the crater rim thickened, keeping the sea away so that lava could flow out, ensuring Surtsey a new lease of life. Geologist Sveinn Jakobsson, is one of the Surtsey-based scientists. He says: "Despite the steady gnawing of the ocean, and the assault of winds and rain, Surtsey will probably stand for some thousands of years - like its sister islands in the
The eruption lasted for three and a half years, concluding in June 1967, which makes it one of the longest eruptions occurring in
The very next spring, in 1964, seeds and a fly were found on Surtsey's shores, borne by the winds, waves and birds. The first plants put down roots in the summer of 1965 and at last count almost 60 species of higher plants had been found on Surtsey.
This genesis of land from the sea, and development of its ecosphere, has provided scientists from all corners of the world with fantastic research opportunities, such as biology, marine biology, geology, biochemistry and microbiology. The sterile, virgin rock of Surtsey is truly a scientific
Many aspects of Surtsey's development have come as a surprise, and even changed scientists' previous assumptions. In the course of only a few years, the rocks on Surtsey's shores were as sea-scourged as those on a shoreline tens of thousands, or even millions of years old. It was almost beyond belief how fast this happened.
Sturla Fridriksson, who has followed the island's development closely from its very inception, points out that Surtsey has disproved the theory that lichens and mosses are necessary first colonisers. He says: "On Surtsey, higher plants [grasses, flowering plants etc] acquired footholds on their own. And seeds are not only borne to Surtsey from
Birds have played the greatest role in the development of the island ecosphere. An incredible number of seabirds nest in the
For some time, the development of Surtsey's ecology was fairly slow, but a turning point was reached in the summer of 1985. An optimistic pair of lesser black-backed gulls nested by a miniture clump of vegetation in the black lava. The following year they reappeared, bringing friends and relatives who also nested in the area.
Nesting birds grew in number with each passing year, soon joined by the herring gull. For their nests, the gulls used the first hardy plants that had taken root on Surtsey, sea rockets, sea sandworts and lyme grass - plants which were already friends to the scientists who visited them each year.
The nesting grounds provided organic fertiliser, while the gulls transported seeds from nearby islands, greatly boosting the variety of vegetation. Soon patches of grass and flowering plants formed and the southern tip of the island became an oasis in the desert of black lava on the wave-beaten shore. Today the area covers approximately 10 hectares.
This intriguing co-habitation between fowl and flora has brought richness and diversity to the habitat. In the summer of 2002, pair of grey-lag geese, with two half-grown chicks, were found on Surtsey - grazing animals had arrived. Now even three willow species have appeared on the island. And so the life forms multiply and support one another; vegetation gradually spreads over the island, soil formation increases and with it diversity of flora and fauna.
Fridriksson is convinced that as time passes, certain plant species will come to dominate, creating ideal conditions for other bird species: "In the future Surtsey will be characterised by large colonies of puffins and gannets, just like the older and more mature
After having inspected this remarkable, bright-green gulls' nesting ground, we set out for the main peak itself. The solid, tuff cliff is quite steep, and strewn with occasional basalt clumps thrown up there from the craters down below. Through a multitude of cracks, steam curls up in the calm weather like breath exhaled from the rock. Along the edges of the cracks are colourful sulphur deposits and I crouch down by one to see whether I can feel any warmth - only to draw my hand back quickly, because the rock is burning hot. Just a little reminder of the slumbering fires beneath.
From the top there is a fine view of the entire island and north to the other
The sun is going down by the time we give Hjálmar the signal where he waits on board the boat offshore. Fortunately, the weather has remained calm - visitors to Surtsey can be trapped on the island for days by extreme currents and heavy surf. But everything proceeds as planned and we make a circuit of the island to say farewell. The perpendicular cliff walls and colourful lava layers stretch above us, with the evening shadows etching the outlines of trolls and monsters.
On Surtsey, nature has given us a unique glimpse into how the forces of creation and destruction wrestle continually with one another. I could not help being impressed by the eternal cycle of nature, reminding me of the words of the Icelandic Viking Age poem, Völuspá, or The Song Of The Sybil. It describes how the fire giant Surtur transforms the world into a horrendous ocean of fire.
"Surtur comes from the south, on his sword the sun of the Valgods... crags topple... cast down from heaven are the hot stars, fumes reek... The sky itself is scorched with fire". But Völuspá also predicts that, after the Twilight of the Gods, the earth will once more rise from the waters, fairer and more fertile than ever. The settlement of Surtsey by various life forms is like a confirmation of this ancient prophecy.
Island Life --
Borgthor Magnusson and Sigurdur Magnusson
How does life develop on a new part of the Earth? Find out more from two plant ecologists who study the once-sterile landscape of Surtsey: Borgthor Magnusson and Sigurdur Magnusson.
What parts of the island had the first plant life and why? Do those areas still have the most plant life today?
(Sigurdur Magnusson) The areas of the island which first became colonized by plants were the sandy and unstable habitats close to the seashore. These habitats are still very poor in plant species and extremely low in cover, mainly due to the repeated disturbance from the sea. However, the main plant colonization started in an area not very far from the seashore but out of the range of the disturbing effects of the Atlantic waves, in a place covered by volcanic sand. At that site two species (Sea Sandwort and Lyme-grass) became established and mainly from that foci they have been able to spread to most other parts of the island. As the time has passed several other species have also been able to establish themselves on the island, but that initial spot still has less than 20 percent plant cover.
Do you believe that the
(Sigurdur Magnusson) I believe that most of the island will become covered by plants, but that will certainly take a long time, probably more than a century or two. The breeding birds will aid the vegetation colonization by fertilizing the soils. The island will, however, never be totally overgrown with vegetation due to the high disturbance from the sea. The seashore and the sea-cliffs will always be relatively poor in plant cover.
The number of animal species like birds, soil animals and flying insects will probably increase in number when new habitats are formed on the island. The puffin will probably colonize the island when suitable nesting habitats have been formed (relatively deep soil covered by grass sward). Habitats now found on the island will probably change with time; therefore, some of the animals now found on the island will very likely be reduced in number.
Why did you stake out the different plots to study plants? How did you initially decide where to place them?
(Sigurdur Magnusson) During the first years after the formation of the island every plant found on Surtsey was marked and given a number in order to follow the plant colonization and establishment. With time more and more plants became established and therefore this method was no longer feasible. Therefore, we decided to establish several permanent plots in different parts of the island in order to study the plant succession and to follow how plant species interact. The plots were placed subjectively in what was considered representative for different vegetation and habitat types on the island, e.g. lava vs. ash substrate, inside/outside gull colony.
Do scientists take precautions not to bring seeds or life to Surtsey? If so, what are these precautions?
(Borgthor Magnusson) Yes, we take precautions and try to avoid all accidental introduction of plants or other life by man to Surtsey. We do this by checking our clothes, footwear and other gear very carefully before visiting the island. We recommend that clothes are washed and all dirt brushed from footwear to remove any soil or plant material. Then we must take care not to walk or wander though vegetated areas before leaving for the island. Although we take these precautions, introduction of plants by man to Surtsey can not be ruled out. However, we have not found any direct evidence of plant introduction by man to the island. The main transport agents of plant seeds or spores to Surtsey have been the sea-currents, the wind and the birds.
Has the atmosphere warmed enough in the past 25 years to affect the plant life found on Surtsey?
(Borgthor Magnusson) We believe that global atmospheric warming has not affected plant life on Surtsey to any degree in the past 25 years. The climate on Surtsey is rather mild with a mean July temperature of 10 deg. C and a frost-free period from early May to mid October. The young and rapidly developing plant life on Surtsey is not the best to study the effects of climatic change. What has been of much greater significance in the last years is the effect the sea-gulls are having on the plants with their addition of nutrients to the soils of Surtsey.
How long do you think it will it take before Surtsey is completely eroded by the
(Borgthor Magnusson) At the end of the eruption in Surtsey in 1967, the island had reached a size of 2.7 sq. km or 270 hectares. Now half of that has been eroded away by the ocean and the island is only about 1.3 sq. km. During the first years Surtsey decreased annually by 3-20 hectares, but in the last years the erosion has slowed down and it has been about 1 hectare annually. The inner core of Surtsey is formed of palagonite tuff which is harder and more resistant to the oceanic waves than the outer lava which is now being eroded. Therefore, Surtsey will gradually, perhaps over a 2 to 3 centuries time, take the shape of the small nearby islands which where also formed in similar eruptions after the last ice age. These islands, which are stacks with steep cliffs and abundant bird life, are only 2 to10 hectares in size. The islands are known to be several thousand years old. Therefore, my prediction is that Surtsey will be there for the next thousand years at least.
I was wondering what species of gulls originally populated Surtsey. I was also wondering if any more species of birds had come since and if these birds had brought more species of plants. Thank you for your time.
(Borgthor Magnusson) There are eight species of birds breeding on Surtsey now. These are the Fulmar and the Black Guillemot (from 1970), Great Black-Back Gull (1974), Kittiwake (1975), Herring Gull (1981), Lesser Black-Back Gull (1985), Glaucous Gull (1993) and Snow Bunting (1996). A Raven has built a nest on Surtsey, but it has bred there. A nest of an Arctic tern has once been found but the species has not established itself on the island. The most abundant breeding birds now are the Lesser Black-Back, the Fulmar and the Herring Gull.
The Great Black-Back was the first gull species to start breeding in Surtsey. The number of pairs has increased to about 40 now. The Great Black-Back is spread over the island and the nests are far apart. We have found no direct evidence of plant introductions to the island with this species. However, plant growth is enhanced around the nests. Often the nests are in the middle of Sea Sandwort or Lyme-grass plants. In roosting areas frequently used by the Great Black-Back near edges of cliffs Scurvygrass became established in the early years of Surtsey. It is possible that the seeds were carried to the island by the birds.
The Fulmar, Black-Guillemot and Kittiwake breed in the sea cliffs which are very unstable and erode from one season to the next. Vegetation has not become established at their nesting sites on the cliffs. There are some Fulmar nests upon the island and vegetation cover has increased close to the nests. We have, however, not found any new plant species associated with the Fulmar nests.
In 1986 we noticed that the Lesser Black-Back and Herring Gull were forming a breeding colony on the southern part of the island. At that time the breeding pairs were less than 10, but now the number has reached over 200. The breeding colony has expanded greatly in range. A few pairs of Glaucous Gull have also joined in.
After the formation of this gull colony on Surtsey the number of new plant introductions has increased greatly and most of the new species have been found and become established within the colony. These gulls build more delicate nests than the Great Black-Back and they may have brought in nesting material from neighbour islands which could be a source of new seeds. Also they feed more on insects and earthworms and are more likely to pick up seeds and bring them to Surtsey. On the island the vegetation cover and species richness is now greatest within the gull colony.
In the summers of 1996 and 1997 we have seen one pair of Snowbuntings feeding their fledglings on Surtsey. A nest has not been found yet but we assume that the birds are breeding on the island. This is the first land bird to breed on Surtsey, feeding on the insects found there. The increase in vegetation and insect life following the formation of the gull colony has probably enabled the Snowbunting to establish itself on Surtsey. We know that these birds can transport seeds. Viable seeds were found in the stomachs of migrating Snowbuntings collected on Surtsey a few years after the formation of the island. However, we have no direct evidence that Snowbuntings are responsible for introducing new plant species to Surtsey.
You provided the meaning of the name "Surtsey" on the program but I did not catch it all. Would you please provide it again?
(Borgthor Magnusson) The island is named after the fire-giant SURTUR. The word Surtsey, means "the
Is there any sign that the volcano that formed Surtsey could erupt again in the near future?
(Borgthor Magnusson) No, there are no signs of that. Geological research on the island shows that Surtsey has gradually been cooling down since the eruption ended in 1967. However, it cannot be ruled out that Surtsey will erupt again, but there are no indications that it will do so in the near future. Surtsey is the southernmost of the
Can you tell us how you are going to use the information you are learning by studying new life on Surtsey?
(Sigurdur Magnusson) The results from Surtsey can be used in several ways. The information can help us to predict how natural plant succession will proceed in other places under similar circumstances, e.g., on new lava fields, on eroded land or following retreat of glaciers. Also, the information on the succession in Surtsey is very important as it can be used to make better restoration plans for severely disturbed areas which are of similar character as Surtsey.
Can you tell us how you are going to use the information you are learning by studying new life on Surtsey?
(Borgthor Magnusson) Findings of the research carried out on Surtsey have been published in scientific reports, papers and books. Also the general public has been informed though articles in newspapers, magazines, TV programs and other media. I would say that this the most important use of the information from Surtsey. But the research also has practical aspects and reference to the land reclamation work that is carried out in many areas of
Could the new plants now growing on Surtsey help slow down the rate of erosion of the island?
(Sigurdur Magnusson) No, the main eroding factor, the waves of the Atlantic ocean, are so powerful that the small plants now growing on Surtsey have no effect to slow down the rate of erosion.
Are only plant scientists studying Surtsey? Or are other scientists also looking at how birds, animals and insects are colonizing the island?
(Borgthor Magnusson): The plant ecologist keeps an eye on the birdlife but it is also followed by ornithologists. The development of insect and other invertebrate fauna has also by studied by specialists in that field but not in the same detail as the plant succession. Colonization of the subtidal zone by marine life has been studied from the first years of the island and the sampling carried out at intervals of a few years.
All geological and biological research on Surtsey is organized by the Surtsey Research Society (
Is Surtsey the first time you've had a chance to study how plants colonize "new" land? What is the most surprising thing you have learned there?
(Sigurdur Magnusson) No, we have also been studying plant colonization on eroded land on the mainland of
There are several surprising things we have learned from our studies.
We find it very interesting to follow how effective the Sea Sandworth (Honkenia peploides) has been in colonizing the island, in spite of the harsh conditions like the abrasion from wind blown material and the low soil nitrogen content. This species is by far the most successful colonist on Surtsey and has now spread over the whole island.
Quite surprising for us is also the fact that the vascular plants are the dominant colonists on Surtsey, but not the lichens or mosses which usually dominate young lava fields in southern
We also find it very interesting to see how the sea gulls have affected plant succession on the island. In the gull colony, which started forming on the island in 1986, there has been a great increase in the number and cover of vascular plants, probably due to increased dispersal to the island and fertilization by the birds.
I was wondering what species of gulls originally populated Surtsey. I was also wondering if any more species of birds had come since and if these birds had brought more species of plants. Thank you for your time.
(Sigurdur Magnusson) No, the radioactive deposition from
Can you make any predictions about the next plants, insects and birds you will see on Surtsey? Could mammals survive there one day?
(Borgthor Magnusson) Yes, I think we can make some predictions about what species are likely to colonize Surtsey in the near future. I will only comment on the plants and the birds as my knowledge of insects is very limited. There are several plant species which are common on the mainland of
The birdlife on Surtsey will change with increasing vegetation cover on the island. The Puffin, which is the most common breeding bird on the nearby islands, has not colonized Surtsey yet. The Puffin breeds in grassland where it digs a hole for the nest deep into the ground. On Surtsey grassland has started to form in the gull colony and with its further development breeding conditions for the Puffin may become favourable within the next twenty years. The Puffin is a seabird and will not have any problems with feeding its young on Surtsey. It is much more difficult for a landbird to start breeding on Surtsey as insects or other prey are not very abundant. A Raven has built a nest on Surtsey but it has not bred there, probably due to a lack of food (eggs and young of smaller birds) in early summer when the young hatch. It will probably be very difficult for the Raven to breed successfully on Surtsey in the future. A pair of Snowbuntings, which feed on insects, has however managed to breed on Surtsey in the last two summers. This species will probably continue to breed on the island as insects will become more abundant with increasing vegetation cover. The Meadow Pipit and the White Wagtail which also are small insectivorous landbirds and very common in
I don't think land mammals will ever colonize Surtsey. The Wood-mouse could probably survive there throughout the year when vegetation becomes more abundant but it will probably never find a way of getting to Surtsey across the sea.
Can you tell us more about the lava tunnel you were in on the show. How long is it? How did it form? Is it safe to climb in a lava tunnel?
(Borgthor Magnusson): That lava tunnel is about 200 m long. At the upper end it is like a big cave, about 5 meters wide and with 3-4 meters height to the roof, from there it becomes narrower and forms a tunnel all the way down to the sea-cliff below where it opens with a nice view over the ocean. In the eruption the tunnel was like a river of lava and when the crater stopped feeding it, the river ran dry, leaving behind the empty tunnel or riverbed. The roof of the tunnel was probably formed in a similar way as ice on a river that freezes over. In the river you will have a flow of water underneath. In the lava river the molten lava will cool at the top, harden and form a crust. Underneath it there will be a stream of lava as long as the crater feeds the tunnel. There are several lava tunnels or caves on Surtsey and this one is the most accessible and it is fairly safe. Most of the others are much bigger and they are not very safe places to visit. To do that people need ropes, helmets and special equipment. They have only been explored by cave geologists and enthusiasts.
How long would it take for an inch of soil to form on the new island?
(Borgthor Magnusson) The soil of Surtsey is still mostly made up of volcanic ash and sand and there has been a very limited build-up of organic matter. It has therefore not changed considerably from the first years after the formation of the island. In parts of the gull colony there is now dense vegetation cover of grass and herbs and underneath that soil formation is more apparent, with root mat and decomposing plant remains. These processes have not been studied in any detail on Surtsey but they are certainly very interesting and important in the developing ecosystem. My feeling is that it will take many years (30-50?) before we have an inch of soil with some decent organic matter content underneath vegetation sward on Surtsey.
The show said that the island, created by the volcanic rock, is about half the size it was when it started. If that's true, then why are continents like
(Borgthor Magnusson) The geologists would answer this question more fully but I will try. Surtsey is a very small island, surrounded by deep waters and exposed to strong southern winds blowing across the
Scientific American Frontiers
COLONIZATION OF THE LAND
(authors: Sturla Friðriksson, Borgþór Magnússon - email@example.com)
How Are the Plants Studied?
At the beginning of research in Surtsey, each new individual among higher plants was observed and its place of discovery and growth registered on a map of the island. Each new plant was labelled with a wooden stick and given an identification number. The growth of the plant was measured and its flowering and seed formation recorded. This was possible while the number of individual plants was small, but when the plants started to disperse their seeds in Surtsey and the rate of reproduction increased, it became impossible to label each individual and observe its development. Instead, permanent plots were set up in different habitats and locations on the island in order to follow plant succession. In addition, changes in the soil and invertebrate fauna in the plots are observed. Furthermore, each summer the island is combed for new pioneers, and the status of all species growing outside the permanent plots is updated. This has given a clear picture of the colonization of higher plants and the increase in the number of species on Surtsey.
Coastal Species Were the First Pioneers
In the first two decades, the sands and lava of Surtsey were quite barren and soil development was poor. Few species are adapted to such conditions and able to grow and reproduce under them. Shore plants that grow on sandy beaches and in windblown sand are adapted to nutrient-poor soils and can survive in severe conditions. Such plants were the first pioneers to colonize Surtsey and were characteristic of the vegetation during the first decades, along with the mosses and lichens that were found early on the island. This first period of plant history in Surtsey was therefore characterized by species adapted to dispersal by the sea or wind and capable of growing and surviving under extreme conditions.
The first higher plant species found in Surtsey was sea rocket (Cakile arctica) in 1965. It was also found there the following year along with sea lyme grass (Leymus arenarius). In 1967 these species were joined by oyster plant (Mertensia maritima) and sea sandwort (Honkenya peploides). In the late summer of that year the sea rocket flowered and was the first species to reach that stage. However, in these first years no higher plants survived overwinter in Surtsey, as they were either buried in the sand or washed away by the winter surf.
The first higher plant to survive over winter was the sea sandwort. The species overlived in the winter of 1968-69, and it has done very well since then. Only a few years passed before it had flowered and formed seeds. The first seeding taking place in 1971, which his was a turning point in the dispersal of this plant, and consequently it´s spread all over the island as the years passed.
Sea sandwort is now by far the most common higher plant species on Surtsey, growing everywhere that any pumice and sand can be found. The number of plants is most likely several million, and the largest ones have formed hummock-like patches with an area of several square meters. Sea sandwort has a well-developed fibre root system growing deep into the sand and beyond the plant surface above ground. In this way it can utilize nutrients from a large area to grow and develop.
It took sea lyme grass and oyster plant a
longer time to reach the flowering and seeding stages. Consequently, these
plants began spreading and forming populations later than the sea sandwort. It
was in the years 1977 - 1979 that sea lyme grass and oyster plant started
seeding and spreading throughout the sands and pumices. Sea lyme grass is a
hardier species and is now one of the most common species on the island. It has
formed several sand dunes decorated with sea sandwort and oyster plant. In this
manner, there has developed on Surtsey a community of shore plants quite
similar to the vegetation on sandy shores of
During the period 1975-1985, following the colonization by the shore plants, very few new species were added to the young flora of Surtsey, and the succession slowed down (graph).
Enhanced Plant Succession with Increased Gull Breeding on Surtsey
The first birds to nest in Surtsey were the fulmar (Fulmarus glacialis) and the black guillemot (Cepphus grylle) in 1970. In 1974, they were joined by the great black-backed gull (Larus marinus), in 1975 by the kittiwake (Rissa tridactyla) and in 1981 by the herring gull (Larus argentatus). Breeding birds were nevertheless very few to begin with, and their influence on the vegetation development was rather limited. In 1986, a lesser black-backed gull (Larus fuscus) was discovered breeding on Surtsey for the first time. At this point in time, a gull colony was beginning to develop on the lava on the southern part of the island, where 10 lesser black-backed gull and herring gull nests were found. A sharp increase in the breeding population occurred over the next few years, and the dense breeding population that had soon developed grew larger each year. In 1990, the number of breeding pairs had risen to 200. By that time lesser black-backed gulls, herring gulls and great black-backed gulls were found in the colony.
This population explosion in the gull colony on Surtsey after 1986 was accompanied by a new wave in the colonization of higher plants and the succession of vegetation. The stagnation that had characterized previous years was broken. A number of new species began to colonize the island, and most of them were discovered within the gull colony. It is likely that many of the species were dispersed to the island by the gulls. In the period 1985-1995, the number of higher plant species on Surtsey grew from 21 to 44. In recent years the increase in number has slowed down. In the summer of 2004, 60 species of higher plants had been found on Surtsey of which 54 had living representatives on the island that year. This shows how the gull invasion has affected plant colonization and survival on Surtsey (graph).
In the gull colony, not only did the species increase in number but the vegetation also became denser due to the fertilizing effects of the birds. In only a few years, the black pumices and lava sands changed into a lush grassland and forb community. By the year 2004, the breeding area on the southern part of the island had expanded to about 10 hectares.
Comparison of Vegetation outside and inside Gull Colony
The succession of vegetation has been observed closely, in permanent plots both outside and inside the gull colony, since 1990. Changes have been slow outside the colony, the most interesting being that species characteristic of gravel plains, especially northern rock cress (Cardaminopsis petraea), sea campion (Silene uniflora) and thrift (Armeria maritima), have been found and are beginning to spread over the island in areas formerly colonized by the sea sandwort, lyme grass and oyster plant. In permanent plots (100 m²) outside the gull colony, the number of plant species recorded in the summer of 2002 ranged from 1-5, and the total plant cover did not reach 30% in any of them. Inside the gull colony there were, on the other hand, up to 10 different species in each plot, and there was a continuous plant cover in some of them.
In sandy areas inside the colony, the most abundant species in the vegetation are the sea sandwort, sea lyme grass, annual meadow grass (Poa annua), common meadow grass (Poa pratensis), common chickweed (Stellaria media), common mouse-ear (Cerastium fontanum) and the sea mayweed (Matricaria maritima), while in the lava the reflexed saltmarsh grass (Puccinellia distans), scurvy grass (Cochlearia officinalis) and procumbent pearlwort (Sagina procumbens) are most prominent. Arctic fescue (Festuca richardsonii) has been found at several sites where it has formed homogenous patches that increase in size from year to year. These patches are similar to grass swards of Arctic fescue, which dominate in many bird colonies of the neighbouring islands.
Northern green orchid (Platenthera hyperborea) and lady’s bedstraw (Galium verum) were found for the first time on Surtsey in the summer of 2003 (see article here, in Icelandic), and both these plants were in lush vegetation in the gull colony. They are examples of species that colonize land where vegetation has been developing for a while. The same is true of a few species of grassland mosses that have begun to colonize the gull colony on Surtsey. This confirms that plant succession on Surtsey is no longer in the primary stage.
Late Invasion by Willows
Dwarf willow (Salix herbacea) was discovered on Surtsey in 1995 and was the first willow species to colonize the island. A few individuals of this species have been found, and in recent years both tea-leaved willow (Salix phylicifolia) and woolly willow (Salix lanata) have been discovered on the island. The willow plants have been found both inside and outside the gull colony. It is likely that the seeds of all these species were dispersed by wind to Surtsey in the early days, but that conditions for their growth and development were not favourable until during the last decade. The improved soil conditions following the gull colonization are probably the main reason for this invasion of willows on Surtsey.
Future Development of Vegetation on Surtsey
The number of higher plants growing on
Surtsey has become considerably higher than of most of the neighbouring
The number of species on Surtsey will continue to rise during coming decades. It is unlikely, however, that the number will ever reach 100. In the future, Surtsey will continue to erode and shrink, with a consequent loss of habitats and species. Surtsey will become similar to its small neighbours, Geirfuglasker and Súlnasker, which have less than 10 plant species in their flora.
- last updated
© Thorleifur Einarsson
Believe it or no, but the population on Surtsey today
has passed 1 million inhabitants. Of course, not all individuells are visuable
to the human eye at first. Some of those indiduells living on Surtsey you can
only see through a microscope. But they are still there.
Some of them are bigger. So lets have a look at them first.
A collembolan. More info at:
collembolans were found on the shore in 1967 and apparently they had floated to
the island on the sea. Since then, new collembolans have arrived each year. All
collembolans collected in the periode from 1967 to 1972 were found in connection
with the shore. However, in 1976 collembolans were for the first time found in
mossy vegetation on the southern lava fields far from the shore.
As per 1978 16 species of collembolans had been found on Surtsey, and it is presumed that they all have arrived either by the sea, the birds or the wind.
together with the mites, enchytraeids and nematodes constitute the soil
meso-fauna. Collembolans live in the air-filled pore system of the soil and
cannot make their own burrows like larger soil animals (macrofauna) as
earthworms. Collembolans and earthworms also inhabit the litter layer at the
And that brings us to the earthworms. The first ones were found on the island in 1993, in soil samples taken in the gull colony. Two approximately 3 cm long juvenile individuals of the species Lumbricus castaneus. No earthworms were found in July 1995, in spite of a thorough search and sampling for the same area.
There is no single answer to how the earthworm dispersed to Surtsey. Most likely they were dispersed by birds from the other islands or from the mainland of
Back to the collembolans again: Five species of collembolans were found in the plots on Surtsey in 1995, and one species in Racomitrium-moss in the crater Gamli Surtur (Old Surtur). Four of these six species hav not been found previously on the island. The dominant species in the plots outside the gull colony were Mesaphorura macrochaeta and Hypogastrura purpurescens in the plots inside the colony. Four species were also found in samples taken in 2000, and two additional species were then also found in the plots.
In the gull-colony the density was as high as 74.724 collembolans in one square-meter, but much lesser in some other plots (10.000 - 20.000 per m²). In 1995, 7 species were found in the soil samples investigated and 1 species on drifting wood on the northern sea shore. The occurrence of collembolans per m² in the different areas in 1995 is shown here:
78 individuals of OXnychiurus duplopunctatus were found under driftwood, not in any of the areas. The two extra species found in J5 were 81 Iisotomiella minor and 41 Pseudisotoma sensibilis. Ceratophysella succinea was only found in J1 (2.397 individuals). The one species dominating all over, was the Hypogastrura purporescens, which however was absent in J1, which is the pioneer plant community with Honkenya peploides and Leymus arenarius.
You might be interested knowing that the total number of both collembolans and mites per square-meter has been counted up to 340.000 individuals in the J6 E area. All together in J1, J5, J5F, J6 and J6E, that equals 5 square meters, there was counted
a total of 1.024.064 individuals.
So far we have had certain difficulties obtaining pictures/photos of those tiny creatures, but we are working on the problem. Any assistance will be highly appreciated!
found for the first time on Surtsey in 1998, and they were also present one
year later. The slugs were found in ta dense grass sward in the gull colony.
Identification to species has not been carried out, but the specimens found on
Surtsey are similar to slugs commonly found in moist grassland and gardens in
Since the volcanic island Surtsey emerged from the sea the dispersal of organisms to the island and the development of biotic communities there have been studied by a number of biologists .The following is a report on the status of the land-arthropod fauna on the island observed during a visit in July 1981.
was generally unsettled. Only on the first day of the research (July 10-16) the
weather was favourable for collecting flying insects, warm south-easterly
gentle breeze and sunshine. The remaining days the wind was sometimes too
strong for field-work, mostly rainy but sandstorms when dry.
1.244 specimens of land-arthropods and 2 oligochaetes. (What's that?). Collembola dominated with 723 specimens (see above on this page). The most dominating species collected were Acyrthosiphon auctus of the Hemiptera-group, 81 Heleomyza borealis, 52 Meoneura lamellata, both belonging to Diptera, then 43 Erigone arctica (Araneae) and finally 71 Neomolgus sp. and 131 Indet.spp (Acari). The largest group of species belonged to the Diptera.
So far, so good. But to me this means just that a lot of different insects were collected. So as usual the net has to be searched to see what to find out about those latin names.
excellent page of Arthropod.net the following were found regarding the Diptera:
'Although many winged insects are commonly called "flies," the name is strictly applicable only to members of the Diptera. It is one of the largest insect orders and contains over 85,000 species; all are relatively small and have soft bodies. Mouth parts are of the sucking type, but there is great variation. Some, like the blood-suckers, are serious pests. Flies are beneficial as scavengers and predators or other insect pests.
Diptera are divided into three large groups: Nematocera (crane flies, midges, gnats, and mosquitoes); the Brachycera (horse flies, robber flies and bee flies); and Cyclorrhapha (flies that breed in vegetable or animal material, both living and dead.)'
It is obvious that some of the species observed on Surtsey have found a suitable habitat and have settled permanently on the island. The island may sometimes be rather inhospitable to some of the smaller organisms. Nonetheless some other species obviously settled on the island for good such as some species of Diptera, some spiders and perhaps also one or two staphylinid beetles.
The first opportunities insects were offered to survive and multiply on the island were probably connected with carcasses drifted ashore and birds dying on the island. A certain amount of competition for carcasses is likely to occur between gulls and the saprophagous insects. In 1981 a number of carcasses were found that had been covered by tephraq, thus inaccessible to gulls. These were inhabited by Heleomyza borealis larvae, a species that proved to be very common on the island in 1981.
questions concerning development and succession of the soil formation and soil
fauna on Surtsey and its possible interaction with the vegetation and gull
colony development still remains a challenging subjects for future research.
Text mainly extracted from reports made by Peter Gjelstrup, The
© Thorleifur Einarsson
Completely exhausted and emaciated, this tiny little bird, a meadow pipit, Anthus pratensis, arrived at Surtsey after a 20-24 hours flight from
On arrival the
weight was only 12.0 grammes!
great black-backed gull larus marinus
Summer 1986, 23 years after the eruption, a few pairs of Larus fuscus were breeding on a lava terrain on the southern part of Surtsey. In he following years they increased largely in numbers, and a colony was slowly formed also including Larus fuscus, Larus marinus and Larus argentatus.
The formation of the gull colony marked a new era in plant colonization and succession on Surtsey, as these gulls had considerably stronger impact than other breeding birds earlier established on the island.
In the first weeks of the Surtsey eruption gulls were seen roosting on the shores of the new-born island. Ever since, birds have been important in the development of the exosystem on Surtsey through enrichment of the soil with their excrements and sispersal of plant seeds to the island.
Fulmar (Fulmarus glacialis) and black guillemot (Cepphus grylle) were the first species of birds to nest on Surtsey in 1970, when one nest of each species was found in the cliffs on the southern part of the island. In 1974 great black-backed gull Larus marinus) started breeding on Surtsey, kittiwake (Rissa tridactyla) in 1975, heering gull (Larus argentatus) in 1981, lesser black-backed gull (Larus fuscus) in 1986 and finally glaucous gull (Larus hyperboreus) in 1993.
The gull species build nests of vegetation, sea-weed, feathers and other available meterial, while the fulmar (Fulmarus glacialis) and black guillemot (Cepphus grylle) do not use nest building materials or only slightly arrange pebbles under their eggs.
The nests of the black guillemot (Cepphus grylle) and kittiwake (Rissa tridactyla) are confined to sea-cliffs of the island, which are very unstable and change considerably between years due to wave erosion. Vegetation has not become established at their nest sites. The kittiwake (Rissa tridactyla), however, roosts in great numbers on the northern ness of Surtsey and enriches the soil with excrements.
In the early years the nests of the fulmar (Fulmarus glacialis) were mostly confined to the sea cliffs but in the last 15 years it has also established nes sites inland, mainly in the cliffs of the old craters where small concentrations of about 5 - 15 pairs are now found in five different locations on the island.
In 1986 the first nests of the lesser black-backed gull (Larus fuscus) were found on a lava flat on the southern part of Surtsey. This marked the initiation of the dense gull colony on the island that now consists of the lesser black-backed (Larus fuscus), herring, (Larus marinus) and glaucous gull (Larus hyperboreus). These species, with the exception of the great black-backed gull (Larus marinus), usually nest in colonies and the nests can be within a short distance (<10 m) of each other. They build nests that are mostly made of plant material.
This clearly shows the connection between the increasing numbers of birds - and the vegetation. The more vegetation - then more nest-building material, and the more birds - the better the soil and so more plants will grow up.
In 1990 more
than 150 pairs were in the colony, but it is estimated that the number had
risen to at least 300 pairs in 1999. When the first plots were established in
the gull colony in 1990 the effects of the gulls on the vegetation were
noticable. At that time only two species were found in each plot and vegetation
cover was around 30% (all Honkenya). In 1998 the number of
species in the plots had risen to between eight and ten and several species in
addition to honkenya etc had attained a high cover in the plots. Total
vegetation cover in the plots at that time had reached 100%. Outside the
gull-colony there has not been
an increase in species number.
were suspected to have negative influence on the development of plant
succession by tearing up plants for use as nest material. It has now become
obvious, that the gulls have proved to be very important components in the
simple life community now established on Surtsey (1981).
Obviously the importance of the gulls was not just confined to the nest. The gulls or their young seek shelter in the Elymus tufts leaving droppings and food remains behind, enriching the soil. A selfsufficient ecosystem has been estabished on Surtsey, composed of vascular plants, fungi, various invertebrates with different demands, birds and no douby different microorganisms. The ecosystem is of course simple and probably unstable, but it is obviously the beginning of a more complicated ecosystem to be developed in the future.
That was in 1981, and since then there is no doubt that it has developed, and so it has to a much larger extent than many thought when Surtsey came up from the bottom of the ocean back there in 1963.
Text mainly extracted from reports made by Borgthór Magnússon and Sigurdur H. Magnússon, Icelandic Institute of Natual History,
© Thorleifur Einarsson
In 1968 the
island was manned during the height of the spring migration period, just one
year after the eruption has finally ceased. A careful observation on all
land-birds stopping on or passing the island en route to the mianland of
of the Britsh Isles. It is well known that under normal conditions most migrants turn first up in spring in South east
On the other
hand, this is now history. The observations to follow were made 34 years ago, and
much has changed since then on this island. The size of the island above
sealevel has been reduced to about 1.6 km², but then the vegetation has
improved considerably, thus making this a nice stopover for exhausted birds.
Another report from 1969 and 1970 is given here
We do at present have no more information on the migration of birds since 1968, but will search for more in the near future.
Now to what could be seen in 1968:
On April 30th two Whooper Swans (cygnus musicus) came flying from SW and headed for the
The Grey Lag Goose (anser anser) were seen on April 17th, and on the 20th and 22nd from 2 to 12 in small flocks passed the island. Some of the birds first circled the island before continuing. Later that week some of them settled on the island. In 2002 a pair breeded on Surtsey and had 3 chickens!
On April 29th two flocks of 20 birds in each flock passed the island and headed northward. The next day another 32 birds passed in the same direction, and about the same time 55 came flying from east and headed for the mainland west of Surtsey after having cirkled it. On May 6th one was sitting among gulls on the northern beach.
Barnacle Goose (branta leucopsis) passed late in April by 35 to 65 in each flock. On April 30th up to seven were seen sitting on the island at the same time.
On May 28 a Red-breasted Merganser (mergus serrator) was swimming close to the shore. Next day one was seen on the lagoon.
On April 30 a Merlin (falco columbarius) stayed on the island the whole day. Early the next day a merlin was encountered where it was eating a wheatear. Later that day another female was seen chasing a meadow pipit round the research station.
© Soenke Morsch
Six oystercatchers (haematopus ostralegus) were repeatedly seen on the shores of the island during late April and early May, and some days as many as 18 were seen at once.
Almost daily from 1 to 9 Redshanks (tringa totanus) were seen. Most of these birds made a stop-over on the island.
A few Dunlins (calidris alpina) were seen on the shores early May. Another species, the Knot (calidris canutus) were observed flying northwards off the island in a flock of about 200 - 500 waders, were most of them were thought to be knots.
This photo has not yet been made available by nature photographer Daniel Bergmann. A portfolio of his nature photography on
Two Ravens (corvus corax) (a pair?) stayed on the
island throught the study period (April 16 - May 10). They were frequently
seen, but no signs of nestbuilding or breeding were observed. They habitually
patrolled the tideline for anything edible, such as dead sea-birds, fishes or
invertebrates washed upon the shore. On May 3 a third raven appeared on the
island, but it was vigorously attcked and chased away by the two resident
Wheatear (oenanthe oenanthe). The first one was seen on April 17. The next one was to appear on April 26. The following days 5 - 10 birds were observed each day until about 15.00 on the 29th when wheatears as well as meadow pipits and white wagtails began to appear in somewhat larger numbers on the island. The next day hundreds of wheatears were present on the island that day. The next days they increased fast, and on May 6 only
2-3 birds were seen.
far as is known Icelandic wheatears apparently winter in W.Africa, but we
must assume that they reach Iceland in spring by way of the western parts of
the British Isles, although it is possible that some may travel direct from
Western Africa or the Iberian Peninsula to Iceland without touching the
or they must have
experienced very adverse weather conditions during their sea-crossing. This
theory can only be accepted if due consideration is taken of the westerly
geographical position of
The first Meadow Pipit (Anthus pratensis), was heard on April 17, but it was not until April 24 that they were observed on the island in some numbers. Flocks up to 25-30 birds were observed but already on the 29th there were only 2-3 birds present on the northern part of the island. It is assumed that the meadow pipit is less powerful flyers than wheaters and consequently less adapted to meet the stresses of long sea-crossings, which in turn causes their
pre-migratory fat reserves to become exhausted before they reach their goal. The fact is that their weight upon arrival on Surtsey is only about 50% of their weight when they leave
motacilla alba like to hunt insects near water
Seen on most
days from April 24 to May 10, was the White
Wagtail (motacilla alba), but only a few birds each
day. On the whole white wagtails did not turn up on the island in large numbers
like the wheatears and they were even considerably less abundant than meadow
pipits. But otherwise their magratory pattern was very similar to that of the
meadow pipits and the wheatears Icelandic white wagtails apparently winter
read more about this bird at
A rare visit was observed on April 17th,
when a Starling (sturnus
vulgaris) showed up. Why was that so strange? This bird was probably
migrant because the indigeneous starling population, which have
become established in
© Thorleifur Einarsson
The first seals to visit Surtsey came frequently soon after its formation. Not many reports exists from the first few years, but when divers began studying the sub-zone around Surtsey, they also could now observe them underwater. So in late summer 1972, while diving to collect subtidal algae etc, a common seal, phoca vitulina L, was observed.
Common Seal, phoca vitulina (not from Surtsey)
Courtesy of: www.wildlife.shetland.co.uk/marine/seals.html
During the period 1980-1980 several seals where counted from aircraft. 1980 on August 11th a number of 20 common seals phoca vitulina, were observed, and again in 1986 about 30 adults were registered.
Grey seal, here with a puppy.(not from Surtsey)
Recognition: Grey and brown fur, sometimes with pattern of blotches; no ears visible; long muzzle; nostrils parallel.
Head/body length: average for males 207cm; for females 180cm; flippers about 25cm. Weight: males 233kg; females 155kg.
© Photo: Gill Sinclair, The Mammal Society
Grey seals, halichoreus grypus, were observed
breeding in 1982, and in 1986 as many as 34 puppies were seen on land as 16
adults in the sea during one overflight. Over the years the number has
increase, and in an observation on
So both common seals and grey seals have already several years ago started breeding on Surtsey, as well as using it as a basking site. They have probably used the sandy northern spit, as a basking site much earlier than they started to breed on it. Fishermen from the isles of Vestmannaeyjar, have noticed seals there regularly, often in great numbers, during the winter-time for many years (1989).
Grey seal pups on the northern sandy spit of the
The picture is taken by Erlingur Hauksson from an aircraft on
Surtsey is in many respects a good breeding
place for seals. The animals there are hardly ever disturbed. Visitors to the
island are very few and come to the island mostly in the summertime. The sandy
northern spit is low and beaching is easy for the animals, even in windy
Close to the island are good fishing grounds for seals. In the summer there is an abundance of saithe, cod and herring just off the cliffs. All year around flatfishes and sea scorpions can be found there to eat.
If the seals in Surtsey continue to get the same protection in years to come, as they have had to daye (and the sea does not wipe away all of the northern tip), then a strong breeding stock of grey seals will probably evolve as well as also a sizable herd of common seals.
(This information on the seals on Surtsey are Based upon a report by Erlingur Hauksson, Iceland Fisheries Laboratories, Reykjavik, in Surtsey Research Progress Report X, 1992.)
Photo: © Blair P. Mott
Photo courtesy of Ocean Futures Society
In the year 1964, a year after the eruption started, only bacteria and diatoms were detected on the littoral rocks. The number of species increased rapidly until about 1970, and then leveled off and has increased slowly since with the number of species fluctuating around 40 to 50 species recorded on each sampling occasion the last ten years. Altogether up to the year 1997 the number of different species totaled 76.
Photo by © Hans Christian Andersen
Most of the species that have been recorded on Surtsey are not permanent residents of the island, but are opportunists that have been found sporadically over the years. Some of these species have only been found once after their discovery like e.g. laminaria digitata an extremely common species in the other islands of the Vestmannaeyjar archipelago.
One of the
species, hincksia recurvata,
has not been found elsewhere in
Among the faithful colonizers are both annual species that possibly invade the island every year from a nearby stand, as probably most of the littoral species do, or survive through the winter in a reduced form. Other colonizers are perennial such as laminaria hyperborea that has been found on every occasion since 1968 and plants of up to 9 years have been collected on Surtsey.
Laminaria hyperborea, a typical view of a Laminaria-stand on top of a boulder at the depth of 10 m at the east coast of Surtsey, in July 1997. The highest plants measure about 1.5 m in stipe length.
© Karl Gunnarsson, courtesy of The Surtsey Research Society
Laminaria hyperboerea had its highest
cover at 10 and 20 m where it formed dense stands on the top of the highest
stones, as shown on the picture above. Brown filaments that consisted of a
mixture of filamentous diatoms, hincksia spp. and/or ectocarpus
spp. Were found at all depths in all years and generally had high cover.
In the sublittoral zone the most conspicuous herbivores observed were echinus esculentus, strongylocentrodus droebachiensis, lacuna vincta and padina pellucida. Elsewhere along the basaltic cliffs the algal growth, although less abundant, represents similar main features as on the east coast. See the picture below:
An underwater photograph showing an area of 60 x 40 cm of the bottom at 15 m at the west coast of Surtsey in July 1997.
Species appearing in the photo are the seaweed species delesseria sanguinea, phycodrys rubens, lomentaria orcadensis and juvenile alaria esculenta.
species are sea star, asterias rubens, sponge, grantia compressa,
mussel, mytilus edulis and hydroid, tubularia larynx.
© Photo Karl Gunnarsson, courtesy of The Surtsey Research Society
the year 1997 or just before, another new record, not expected in Surtsey, was omphalophyllum ulvaceum. It was
found in the sublittoral zone at the depth of 10m. This species has not been recorded in southern
The faunal assemblage of alcyonium digitatum at a depth of 30 meters off the island Hæna. (not Surtsey) A deep water community situated between 20 and 30 m depth off Surtsey
is dominated by faunal assemblage of filter feeders, where the soft coral alcyonium digitatum and hydroids are dominant.
©courtesy of The Surtsey Research Society
The highest cover of sublittoral species was in the depth interval from 5 to 15 m after which the cover decreases rapidly with depth and is down to 1.6% at 30 m. The main factor influencing the depth distribution of the algae is most likely light, which is very reduced at 30 m depth. Increasing cover of animals coincides with the decrease in algal cover. Below 25 m the algae have almost disapperaed and the animals are predominating.
alcyonium digitatum at Surtsey in 1974
© Photo: Halldòr Dagsson. Courtesy of The Surtsey Research Society
Mermaid purses from Surtsey covered with seed.
Seeds came to Surtsey in many ways. Some by the birds, and some as passengers on the mermaid purses, eggs of the skate-fish, (raja batis). These eggs are found inside small packets that are drifting around in the sea. During the month of May 1969 several of those capsulated eggs drifted ashore on Surtsey.
The chitinous material of the purses was
somewhat shedded into thin bristles which the seeds stuck to. Some of the seed
were hairy which even increased the adhesion effect. Except for one infertile
fruit of carex (see yellow frame above),
the seed found attached to the mermaid purses were all of grass species,
which are common in
A total of 131 seeds belonging to about 10 different species were collected.
© Thorleifur Einarsson
Colonization of life on Surtsey has been studied since the formation of the island. Investigation carried out in the early days revealed that bacteria and fungi soon became established in the fresh volcanic substrate.
In the summer of 1965 the first vascular plant was found growing on Surtsey, mosses became visible in 1968 and lichens were first found on the Surtsey lava in 1970. Plant colonization on Surtsey has been closely studied, the vascular plants in particular as they have been of far greater significance than mosses and lichens in the vegetation development.
Plot 14 in 1998 on sand-filled lava outside gull-colony.
Honkenya peploides had 2% cover, and was the only species in the plot.
Photo by © Borgthor Magnusson (taken from Magnusson & Magnusson 2000)
The island has been visited every summer and a record kept of colonizing species and their fate. Initially, each individual plant that was found on Surtsey was marked on a map and given a label. Measurements were made of its growth and development, through the summer and from year to year.
Such detailed observations were possible while the number of plants on the island was relatively small and it was continued until 1978. After that time the focus has been more on particular sites on the island where the general development has been followed.
The first twenty years of vegetation colonization and succession on Surtsey were characterized by invasion and spread of the coastal species Honkenya peploides, Leymus arenarius and Mertensia maritima which formed a simple community on the unfertile, sandy substrate on the island. Of the other seventeen species discovered on the island during that period only seven managed to become established and spread slightly but they were all insignificant in the vegetation.
Map showing vegetation 1969, 1970 and 1976, while they yet counted every single plant on the island. Red and blue have been enlargened to show where the plants are growing.
Notice the change
in the formation if the island.
© Map from Surtsey Research Progress Report IX ' Vascular plants on Surtsey 1977-1980 ' by Sturla Fridriksson
At the end of the eruption in June 1967, the island had reached 2,7 km² in total area. The highest point on Surtsey, 154 m asl, is on the eastern hill. The southern part of the island is formed by lavaflows descending from the craters. The lava flows have to a large extent been filled in by drifting tephra sand from the hills above them. The lava in the southeasternmost part of Surtsey is though still mostly free of sand, but airborne dust has settled in hollws and fissures.
The northernmost part of Surtsey is a low ness, formed by eroded material carried by the surf to the leeward side of the island. During winter sea water may wash over the ness area in extreme storms. The coastal erosion has taken its toll of Surtsey and in 1998 the island had been reduced to 1,5 km².
The formation of the gull colony marked a new era in plant colonization and succession on Surtsey as these gulls had considerably stronger impact than other breeding birds earlier established on the island.
Number of vascular plant species found on Surtsey during 1965-1999
© Taken from: Magnusson & Magnusson 2000.
The vegetation succession on Surtsey has changed considerably after the formation of the gull colony. A number of new plant species have colonized the island, the nutrient status of the soil has improved which has enabled nutrient demanding plants to become established and also improved the condition of older species on the island. The main species that have taken advantage of the improved conditions within the colony area are Sagina procumbens, Poa annua, P.pratensis, Puccinellia distans, Cerastium fontanum, Cochlearia officinalis and Stellaria media. Most of these species prefer disturbed and/or nutrient-rich habitats and have a high seed production. Poa annua and stallaria media are annuals, but annual species had not been able to become firmly estabished on Surtsey before the formation of the gull colony.
Plot 1 in 1998, on sanmd-filled lava inside gull colony. The plot had 9 plant species in 1998 and extent of bare ground was only 8%.