Week 3 and…the last one

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This week we had company at the station, a large group of hydrologist’s students from Moscow University. We give some in situ lectures about our project and about the significance of the hyporheic biota studies in Arctic environment.

Fieldtrip lecture during ArcticOsCop project
Fieldtrip lecture during ArcticOsCop project

The ultimate goal was the last survey of the hyporheic zone that offer us astonishments, one site is dry, the most instable one closer to the Storgläciaren.

Nordjåkk River, Tarfala Valley (Sweden)
Nordjåkk River, Tarfala Valley (Sweden)

Good moment for Javier to take the sediments samples. Peter Jansson from the Department of Physical Geography and Quaternary Geology at Stockholm University explains us the environmental monitoring program of the world´s longest record of mass balance measurements of Storglaciären and its behavior in the last years. In 1920 the glacier was reaching the valley bottom and our site was completely covered by ice at the time.

Storglaciären in 1921 (http://hanson.geog.udel.edu/~hanson/hanson/Storglaciaren.html)
Storglaciären in 1921 (http://hanson.geog.udel.edu/~hanson/hanson/Storglaciaren.html)
http://ww2.ink.su.se/bildgalleri/downloads/Massforandringar_storglaciaren_1880.jpg
http://ww2.ink.su.se/bildgalleri/downloads/Massforandringar_storglaciaren_1880.jpg

When glaciers start to retreat the hyporheic organisms start to colonize the new vacant niches. The majorities are adapted to cold temperature, to the instability of the habitats and have short life cycle in order to cope with the harsh climatic environments offered by glacier-feed rivers. We would want to know if the time is sufficiently enough as the hyporheic zone of rivers in the Tarfala valley to be colonized by organisms and to perceive their strategies adopted for dispersion. This information’s would help us understand and predicts their distribution and the effect of warming on typical hyporheic species in Arctic ecosystems. So we decide to goes more down in the glacier foreland, where the Nordjåkk and Tarfalajåkken Rivers meet and survey the small creeks. It was easily observed the differences in vegetation in the surroundings with abundant moss, alpine plants and accumulations of detritus material deposited in the tinny ponds. We expect here a different community with more diversity than in the glacier proximity allowing determining the spatial extent of biota distribution in the glaciers foreland.

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Our work in the Tarfala Valley in Swedish Lapland is closer to the end. Mission was accomplished with the inherent fieldwork complications, but pleased that our time spend there was a great opportunity to work in an environment that is still untouched by human expansion. Thanks to all who makes our expedition to the Arctic a unforgettable experience.

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Week 2

Monitoring hyporheic zone
Monitoring hyporheic zone

After few days of rain, we started the first planned sampling survey. Liters of water pumped, few pipes broken, few other clogged, and eventually we had everything that we had intended. However, the first hyporheic animals, besides common insect larvae, which appeared in our samples were tartigrades (also known as waterbears), nematods and oligochaetes found in one of the most remote site from the river fed by Isfallglaciären, almost 700 m far from the glacier.

The temperature data loggers also did their job (at least for the moment) and the first check showed a constant temperature in the hyporheic 40 cm down in stream riverbed sediments in comparison with the river course: 0.2°C at sites closer to the glacier input and slightly increasing up to 1.7°C downstream. And questions start to rise for all of us. Is the patchy permafrost closer to the surface bellow the riverbed? As the snowpacks are still present at the riverside, do they influence the water temperature of the hyporheic zone? Who may live down there? We would see later on.

Water temperature measurements in the hyporheic zone (black probes) and the river bottom (white probes) at four sites in Tarfalajåkken River

A broad overview of a river biodiversity implies also a screening of its watershed, in a larger variety of aquatic habitats. We enjoyed the daily-trips in the surroundings to discover the beautiful landscape and sampling temporary creeks, pools, lakes and a single borehole.

Sampling of additional aquatic habitats in the Tarfalajåkken watershed
Sampling of additional aquatic habitats in the Tarfalajåkken watershed

And… the first copepods found, adult and juvenile cyclopoids in a lake nearest to Isfallglaciären. However, it is time for a coffee break, and sorry for the rest of the crew… no beer at all.

Next some more info about the last week in Tarfala, keep you updated,

Sanda, Javier & Tadek

Going north…. far north! Far from what….a friend would ask!

Over the next 3 weeks (with no beer at all), we moved our “offices” to Tarfala, a research field station of Stockholm University.Our travel starts from Madrid (me and Javier) and Gdansk (Tadek), respectively, at 24°C, and we arrived in Stockholm at 27°C! How much would be more north? Weather forecast says 21°C for today (11 July 2014) in the Tarfala valley. We would see after the last flight…

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From Nikkalotka to Tarfala valley we flew with a Colibri helicopter that had to carry our 450 kg

Tarfala Research Station is located in northern Sweden (67°54.7’N, 18°36.7’E, 1135 masl) in a high-sub-Arctic alpine valley. Beautiful landscape, speechless, and it’s a privilege to work here.

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The glacierized catchment of the Tarfala valley covers an area of 20.6 km2 and drains into Tarfalajåkken. The most important glaciers are Storglaciären and Isfallsglaciären. The area is treeless and during summer shrubs herbs, mosses and lichens emerge.

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Tarfala valley

Why glacier-fed rivers are so interesting?

Even more, why are we interested what is below the channel, in the riverbed sediments, in the so-called hyporheic zone? Glacier-fed rivers have a variety of habitats from the glacier to the downstream sections. The hyporheic zone hosts diverse communities of invertebrates, including crustaceans that might live up to 1 m depth into the riverbed sediments. For several of these organisms living in glacierised watersheds the summer is the key-period for developing their populations.

After a day-trip in the valley in our first day in Tarfala, we selected the sampling points along the Tarfalajåkken river.

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Tarfala Valley

We are monitoring several environmental parameters of the hyporheic zone, among these the water temperature which is one of the important factor structuring the composition and distribution of biota in glacier-fed rivers. The day 2 was devoted to installing data loggers in order to obtain the range and difference of temporal temperature fluctuations of the river and hyporheic waters. It was not an easy task at many points to find the suitable places to install the loggers in the rocky riverbed, anticipating difficulties in the next days when we have to install the sampling pipes for animals.

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After four sunny days of almost 20°C (some kind of Ibiza summer by the local standards), allowing us to install all devices, today it rains. It’s time then to discuss the plans for the next days.

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Greetings,

Sanda, Javier and Tadek

ARCTICOSCOP – ARCTIC OSTRACODS AND COPEPODS OF THE HYPORHEIC ZONE IN SWEDISH LAPLAND – ASSEMBLAGES’ RESILIENCE AND SHELL CHEMISTRY

The resilience of hyporheic biota in Arctic streams is strongly controlled by long-lasting stress related to persistently low water temperatures, prolonged ice-cover, permafrost occurence, strong freeze-thaw cycles, nutrient availability, and frequent disturbance of their physical habitats. Consequently, the structural pattern of hyporheic biota is distinct in biodiversity, ecology, morphological, life-cycle and behavior adaptations in order to ensure their resistance and persistence under adverse environmental conditions. The hydrological and chemical processes occurring in the hyporheic zone in Arctic streams have received increased attention in recent years, yet the studies on primary succession of biotic assemblage and their response to cope with extreme environmental conditions are still scarce.

The ArticOsCop project funded through the European Union’s INTERACT funding scheme will assess the effect of habitat instability and changing environmental settings on the resilience of ostracod and copepods communities from the hyporheic zone in glacier-fed rivers. During July 2104 we will conduct our research in the Storglaciaren valley at the Tarfala station (Swedesh Lappland). We will perform a combination of field monitoring surveys – biota, water discharge, temperature, sediment structure, (geo)chemical analyses of water, sediments analyses (via CHNS/O elemental analyzes; micro-XRF and susceptibility) and ostracods shell geochemistry (Mg/Ca, Sr/Ca and 13C/12C).