Arctic Coastal Areas Research Articles

International Law Issues Concerning Marine Environment Protection in the Arctic

International Law Issues Concerning Marine Environment Protection in the Arctic

The Role of Coastal Yedoma Deposits and Continental Shelf Sediments in the Arctic Ocean Silicon Cycle

AbstractThe availability of silicon (Si) in the ocean plays an important role in regulating biogeochemical and ecological processes. The Si budget of the Arctic Ocean appears balanced, with inputs equivalent to outputs, though it is unclear how a changing climate might aggravate this balance. In this study, we focus on Si cycling in Arctic coastal areas and continental shelf sediments to better constrain the Arctic Ocean Si budget. We provide the first estimate of amorphous Si (ASi) loading from erosion of coastal Yedoma deposits (30–90 Gmol yr−1), demonstrating comparable rates to particulate Si loading from rivers (10–90 Gmol yr−1). We found a positive relationship between surface sediment ASi and organic matter content on continental shelves. Combining these values with published Arctic shelf sediment properties and burial rates we estimate 70 Gmol Si yr−1 is buried on Arctic continental shelves, equivalent to 4.5% of all Si inputs to the Arctic Ocean. Sediment dissolved Si fluxes increased with distance from river mouths along cruise transects of shelf regions influenced by major rivers in the Laptev and East Siberian seas. On an annual basis, we estimate that Arctic shelf sediments recycle approximately up to twice as much DSi (680 Gmol Si) as is loaded from rivers (340–500 Gmol Si).

Ресурсы ветра западного сектора Арктической зоны Российской Федерации и возможные направления их использования

The authors consider the potential and technical resources of wind energy in the Western sector of the Arctic zone of the Russian Federation. They have stated that increased wind speeds take place in the Arctic coastal areas. Their average annual values ​​at a height of 10 m reach 6—8 m/s. The strongest winds are observed in winter. It is during this period that the demand for heat and electricity from all categories of consumers is maximum, which is a significant prerequisite for the use of wind energy. On the example of the Murmansk region, the authors show the prospects for the use of wind-driven power plants (WPPs) for the production of electricity as part of the Kola electric power system, where there are 17 hydroelectric power plants that can compensate for the variability in the supply of wind energy. Promising is the joint work of WPPs with diesel power plants and boiler plants. The positive effect of such work is expressed in saving the imported fuel and reducing harmful emissions into the environment. The authors propose promising sites for the construction of energy complexes focused on the production of environmentally friendly hydrogen through the use of high-potential wind resources.

Copepod Assemblages in A Large Arctic Coastal Area: A Baseline Summer Study

To provide a baseline description of copepod assemblages in the Pechora Sea, an estuarine area with great economical and ecological importance, we conducted a survey during the summer season. A total of 24 copepod taxa were identified in the study, with Acartia longiremis, Calanus finmarchicus, Centropages hamatus, Copepoda nauplii, Eurytemora affinis, Oithona similis, Pseudocalanus spp., and Temora longicornis being the most numerous. The high diversity (Shannon index = 2.51 ± 0.06), density (18,720 ± 3376 individuals m−3) and biomass (89 ± 18 mg dry mass m−3) of copepods were revealed. Populations of common small copepod taxa were dominated by the young stages, indicating spawning, while older copepodites prevailed among medium- and large-sized species, showing that their reproduction occurred before our survey. Cluster analysis indicated three groups of stations that mainly differed in the abundance of particular species. There were clear associations between copepod assemblages and environmental variables. Statistical analyses showed significant correlations between copepod abundance and water temperature or sampling depth, while other factors had a lesser influence. Our results suggest a strong effect of local circulation and currents on the spatial pattern of the copepod assemblages in the study area. This study may be useful for future biomonitoring in the south-eastern Barents Sea.

Efficiency of sorption-biological treatment of oil-polluted coastal areas in the Euro-Arctic region

A biotechnology based on sorption-biological treatment for the restoration of the Arctic coastal areas after oil spills was proposed. A hydrocarbon-oxidizing microbial preparation based on microfungi (Penicillium janthinellum, Penicillium simplicissimum) and bacteria (Pseudomonas fluorescens, Pseudomonas putida) was created. Granular activated carbon, thermoactivated vermiculite, and peat were used as sorbents. The sorbents are concentration centers for microorganisms, prevent the spread of hydrocarbons, and improve the condition of the polluted substrate by optimizing the water-air regime. After treatment, sorbents are not removed from the soil. As a result of laboratory studies at +10°C, the hydrocarbon content in the polluted coastal sand was reduced by 44-60%, and in the coastal soil by 25-68% after three months. This technology can be used at the final stage of coastal areas cleaning, as well as the only method of cleaning in highly sensitive areas. The use of aboriginal hydrocarbon-oxidizing microorganisms, typical of most coastal substrates of the Euro-Arctic region, excludes changes in the structure of the microbial community in these areas. The adaptation of these microorganisms to extreme climatic conditions allows biological treatment to be carried out with high efficiency in the Subarctic and Arctic.

Global Snow- and Ice-Related Disaster Risk: A Review

Since the 1970s, the ongoing retreat of the global cryosphere has been affecting human societies and causing a series of snow- and ice-related disasters (SIRDs). Based on existing research results, this paper focuses on searching for the formation mechanism of SIRDs, classifies their types and spatiotemporal scales, and reveals the integrated impacts of the SIRD and its future situation on global high-hazard areas. On land, SIRDs mainly occur in the high mountainous areas of middle–low latitude and the permafrost regions of high latitude, in the behaviors of increasing frequency of glacier/snow/glacier lake outburst flood–related disasters and an expanding range of freeze–thaw disasters. The recorded frost events show a decreasing trend but the hail hazard distributions are greatly heterogenous. Overall, the frequency of rain-on-snow events is projected to increase on land in the future. In the ocean, SIRDs are mainly distributed in the Arctic coastal areas and global low-lying islands or areas, with great potential risk. Among them, coastal freeze–thaw, icebergs, and sea-level rise and its impacts are likely or expected to continue increasing in the next few decades.

The Study of Soil Bacterial Diversity and the Influence of Soil Physicochemical Factors in Meltwater Region of Ny-Ålesund, Arctic

Global climate change has caused the changes of the ecological environment in the Arctic region, including sea ice melting, runoff increase, glacial lake expansion, and a typical meltwater area has formed in the Arctic coastal area. In this study, the meltwater areas near six different characteristic areas of Ny-Ålesund in 2018 were taken as the research objects, and high-throughput sequencing of V3–V4 regions of all samples were performed using 16S rDNA. Among the soil samples of six glacial meltwater areas in Ny-Ålesund, Arctic, the meltwater area near the reservoir bay had the highest bacterial abundance, and the meltwater area near the sand had the lowest one. The dominant phyla in soil samples were Proteobacteria, Actinobacteria, Acidobacteria. The NH4+-N content in intertidal soil was higher than that in subtidal soil. Through WGCNA analysis and LEFSE analysis, it was found that the core bacteria significantly related to NH4+-N were basically distributed in the intertidal area. For example, Nitrosomonadaceae, Nitrospira and Sphingomonas were the core bacteria showed significant different abundance in the intertidal area, which have the ability to metabolize NH4+-N. Our findings suggest that NH4+-N plays an important role in soil bacterial community structure in the Arctic meltwater areas.

Seasonal pollutant levels in littoral high-Arctic amphipods in relation to food sources and terrestrial run-off

Increasing terrestrial run-off from melting glaciers and thawing permafrost to Arctic coastal areas is expected to facilitate re-mobilization of stored legacy persistent organic pollutants (POPs) and mercury (Hg), potentially increasing exposure to these contaminants for coastal benthic organisms. We quantified chlorinated POPs and Hg concentrations, lipid content and multiple dietary markers, in a littoral deposit-feeding amphipod Gammarus setosus and sediments during the melting period from April to August in Adventelva river estuary in Svalbard, a Norwegian Arctic Aarchipelago. There was an overall decrease in concentrations of ∑POPs from April to August (from 58 ± 23 to 13 ± 4 ng/g lipid weight; lw), Hg (from 5.6 ± 0.7 to 4.1 ± 0.5 ng/g dry weight; dw) and Methyl Hg (MeHg) (from 5 ± 1 to 0.8 ± 0.7 ng/g dw) in G. setosus. However, we observed a seasonal peak in penta- and hexachlorobenzene (PeCB and HCB) in May (2.44 ± 0.3 and 23.6 ± 1.7 ng/g lw). Sediment concentrations of POPs and Hg (dw) only partly correlated with the contaminant concentrations in G. setosus. Dietary markers, including fatty acids and carbon and nitrogen stable isotopes, indicated a diet of settled phytoplankton in May–July and a broader range of carbon sources after the spring bloom. Phytoplankton utilization and chlorobenzene concentrations in G. setosus exhibited similar seasonal patterns, suggesting a dietary uptake of chlorobenzenes that is delivered to the aquatic environment during spring snowmelt. The seasonal decrease in contaminant concentrations in G. setosus could be related to seasonal changes in dietary contaminant exposure and amphipod ecology. Furthermore, this decrease implies that terrestrial run-off is not a significant source of re-mobilized Hg and legacy POPs to littoral amphipods in the Adventelva river estuary during the melt season.

Remote Sensing Analysis of Erosion in Arctic Coastal Areas of Alaska and Eastern Siberia

In this study, remote sensing analysis of coastal erosion is conducted for three typical regions of Alaska and Eastern Siberia based on remote sensing data collected between 1974 and 2017. The comparative studies were made on the difference in coastal erosion at different latitudes and the difference and influencing factors in coastal erosion at similar latitudes. The coastline retreatment is used to indicate coastal erosion. It is found that the most extensive erosion occurred along Alaska’s coast, followed by that of the Eastern Siberian coasts. Based on the analysis of the historical time series of snow and ice as well as climate data, it is found that at similar latitudes, the erosion of the Arctic coasts is closely related to the trend and fluctuations of the sea surface temperature (SST). Specifically, it is found that in Alaska, coastal erosion is closely related to the fluctuation of the SST, while in Eastern Siberia, it is related to the increasing or decreasing trend of the SST. A decreasing trend is associated with low coastal erosion, whereas an increasing trend is associated with accelerated coastal erosion. In the Arctic, the strong fluctuations of the SST, the continuous decline of the sea ice cover, and the consequent increase of the significant wave height are the critical factors that cause changes in coastal permafrost and coastal erosion.

Demographic security of the far eastern geostrategic territories of Russia

The article presents an analysis of the demographic situation of the border and priority geostrategic territories of the Russian Far East, identified in the «Strategy of Spatial Development of the Russian Federation until 2025». The main problem of the Far Eastern geostrategic territories of the country is depopulation, which is both a factor that slows down the socio-economic development of the macroregion and a trend that can lead to threats to national security. The latter may be most significant for the sparsely populated and almost uninhabited Far Eastern territories located both in the south of the Far East (especially along the border with China) and in the north of the macroregion along the Northern Sea Route, in the development of which not only Russia but also some foreign countries, primarily China, are interested. The analysis was carried out using the database «Municipal Russia», which summarizes demographic statistics for all urban districts and municipal districts of the country, including those located on geostrategic territories. The results of the analysis showed that even in relatively prosperous regions from a demographic point of view, where since 2010 There is an increase in the population, in their border areas (Republic of Buryatia) or Arctic coastal areas (Republic of Sakha (Yakutia)). In municipalities, the already small population is usually declining, which can create threats to demographic security for the entire Russian Federation. To solve this problem, it is necessary to organize monitoring of the dynamics and ethnic composition of the population, the development of special measures of demographic and migration policy

Nearshore Zone Dynamics Determine Pathway of Organic Carbon From Eroding Permafrost Coasts

Collapse of permafrost coasts delivers large quantities of particulate organic carbon (POC) to Arctic coastal areas. With rapidly changing environmental conditions, sediment and organic carbon (OC) mobilization and transport pathways are also changing. Here, we assess the sources and sinks of POC in the highly dynamic nearshore zone of Herschel Island‐Qikiqtaruk (Yukon, Canada). Our results show that POC concentrations sharply decrease, from 15.9 to 0.3 mg L−1, within the first 100–300 m offshore. Simultaneously, radiocarbon ages of POC drop from 16,400 to 3,600 14C years, indicating rapid settling of old permafrost POC to underlying sediments. This suggests that permafrost OC is, apart from a very narrow resuspension zone (<5 m water depth), predominantly deposited in nearshore sediments. While long‐term storage of permafrost OC in marine sediments potentially limits biodegradation and its subsequent release as greenhouse gas, resuspension of fine‐grained, OC‐rich sediments in the nearshore zone potentially enhances OC turnover.

Nitrogen Compounds in the Soil of the Continental Margins of the European Russian Arctic

The specific features in the distribution of organic and mineral nitrogen compounds in marsh and tundra soils of the European Russian Arctic (coastal areas of the Barents and White Seas) were analyzed. Total nitrogen was determined by gas chromatography (CHNS-O elemental analyzer), and inorganic nitrogen, by photometry. The composition of hydrolyzable amino acids was analyzed by liquid chromatography on ion exchange resins. Mineral compounds accounted for an insignificant part of the total soil nitrogen; its major part (to 97% of the total content) was represented by organic substances (Nоrg). The Nоrg varied within a wide range in both marsh (0.3–15.8 g/kg) and tundra soils (5–20 g/kg in the peat horizons and 0.3–2 g/kg in the mineral horizons). The content of N- $${\text{NH}}_{4}^{ + }$$ varied from 5 to 20 mg/kg in marsh soils and from 30 to 200 mg/kg in tundra soils. In marsh soils, the content of nitrate nitrogen was 0.2–4.6 mg/kg in the upper horizons. Marsh soils were characterized by the accumulation of Nоrg either on the surface or in the middle part of the profile in the presence of humus-accumulative horizons buried under recent marine sediments. The accumulation of Nоrg and N- $${\text{NH}}_{4}^{ + }$$ was observed above the permafrost in the peat-gley soil and in the permafrost in the oligotrophic peat soil. The content of hydrolyzable amino acids in the soils of different geneses was 0.6–8 g/kg, which corresponded to 30–60% of the soil organic nitrogen and 2–12% of the soil organic carbon. Distribution patterns of the amino acid nitrogen and organic nitrogen in the soil profiles were similar. The qualitative composition of amino compounds was relatively uniform, and the ratios of most of them were close. The shares of arginine, histidine, phenylalanine, tyrosine, and isoleucine were less than 4% each; of lysine, valine, proline, serine, and threonine, 5 to 7%; and of alanine and leucine, 10–12%. The share of glycine increased downward the profile from 12 to 20%, and the shares of aspartic and glutamic acids decreased from 11 to 6%. In marsh soils, Nоrg, N- $${\text{NH}}_{4}^{ + }$$ , and nitrogen of most amino acids correlated (r = 0.6–0.9) with the clay content and nonsilicate iron forms. The tightest correlations were observed between the dithionite-soluble iron and the nitrogen of threonine and histidine.

Shipborne observations reveal contrasting Arctic marine, Arctic terrestrial and Pacific marine aerosol properties

Abstract. There are few shipborne observations addressing the factors influencing the relationships of the formation and growth of aerosol particles with cloud condensation nuclei (CCN) in remote marine environments. In this study, the physical properties of aerosol particles throughout the Arctic Ocean and Pacific Ocean were measured aboard the Korean icebreaker R/V Araon during the summer of 2017 for 25 d. A number of new particle formation (NPF) events and growth were frequently observed in both Arctic terrestrial and Arctic marine air masses. By striking contrast, NPF events were not detected in Pacific marine air masses. Three major aerosol categories are therefore discussed: (1) Arctic marine (aerosol number concentration CN2.5: 413±442 cm−3), (2) Arctic terrestrial (CN2.5: 1622±1450 cm−3) and (3) Pacific marine (CN2.5: 397±185 cm−3), following air mass back-trajectory analysis. A major conclusion of this study is not only that the Arctic Ocean is a major source of secondary aerosol formation relative to the Pacific Ocean but also that open-ocean sympagic and terrestrially influenced coastal ecosystems both contribute to shaping aerosol size distributions. We suggest that terrestrial ecosystems – including river outflows and tundra – strongly affect aerosol emissions in the Arctic coastal areas, possibly more than anthropogenic Arctic emissions. The increased river discharge, tundra emissions and melting sea ice should be considered in future Arctic atmospheric composition and climate simulations. The average CCN concentrations at a supersaturation ratios of 0.4 % were 35±40 cm−3, 71±47 cm−3 and 204±87 cm−3 for Arctic marine, Arctic terrestrial and Pacific marine aerosol categories, respectively. Our results aim to help evaluate how anthropogenic and natural atmospheric sources and processes affect the aerosol composition and cloud properties.

Economic Cluster Analisis and Fuzzy Modelling of Operation of Wind Power Plants in the Arctic

Renewable resources are of particular importance in decentralized power systems typical of the Arctic and remote areas of a number of countries. One of the fastest growing renewable energy sources is kinetic wind energy used for power generation. Over the past two decades alone, the installed capacity of wind turbines in the European Union has increased hundreds of times, with a significant reduction in the cost of generation. The article discusses some aspects and features of wind power development in Northern and remote areas. In some areas of the Arctic coastal and remote areas, the wind speed has a fairly large value; on the one hand, it is considered highly favourable conditions for the economically efficient use of wind energy. On the other hand, wind speed exceeding certain limits can cause significant loads to be placed on wind turbines components and parts, resulting in the destruction of the device as a whole. The article discusses the possibilities of improving the reliability and durability of wind turbines operating under extreme loads. In addition, as a rule, wind farms are used where the wind speed is characterized by appropriate values, in places with low terrain and a shortage of natural resources. On the basis of methods of multidimensional scaling, cluster analysis, fuzzy modelling, the article investigates the possibilities for determining the most suitable, from the point of view of economic efficiency, places for installation of wind farms with optimization of schemes of their joint application. The technique of determining the wind characteristics and taking into account these characteristics to identify regions with the most favourable conditions for the use of wind turbines and the development of wind power in general are shown.

Spatial and Temporal Variations in the Extent and Thickness of Arctic Landfast Ice

Analyses of landfast ice in Arctic coastal areas provide a comprehensive understanding of the variations in Arctic sea ice and generate data for studies on the utilization of the Arctic passages. Based on our analysis, Arctic landfast ice mainly appears in January–June and is distributed within the narrow straits of the Canadian Archipelago (nearly 40%), the coastal areas of the East Siberian Sea, the Laptev Sea, and the Kara Sea. From 1976–2018, the landfast ice extent gradually decreased at an average rate of −1.1 ± 0.5 × 104 km2/yr (10.5% per decade), while the rate of decrease for entire Arctic sea ice was −6.0 ± 2.4 × 104 km2/yr (5.2% per decade). The annual maximum extent reached 2.3 × 106 km2 in the early 1980s, and by 2018, the maximum extent decreased by 0.6 × 106 km2, which is an area approximately equivalent the Laptev Sea. The mean duration of Arctic landfast ice is 44 weeks, which has gradually been reduced at a rate of −0.06 ± 0.03 weeks/yr. Regional landfast ice extent decreases in 16 of the 17 subregions except for the Bering Sea, making it the only subregion where both the extent and duration increases. The maximum mean landfast ice thickness appears in the northern Canadian Archipelago (&gt;2.5 m), with the highest increasing trend (0.1 m/yr). In the Northeast Passage, the mean landfast ice thickness is 1.57 m, with a slight decreasing trend of −1.2 cm/yr, which is smaller than that for entire Arctic sea ice (−5.1 cm/yr). The smaller decreasing trend in the landfast ice extent and thickness suggests that the well-known Arctic sea ice decline largely occurred in the pack ice zone, while the larger relative extent loss indicates a faster ice free future in the landfast ice zone.

Dicarboxylic and Oxocarboxylic Acids in the Arctic Coastal Ocean (Beaufort Sea‐Mackenzie Margin)

AbstractThe distribution of bifunctional carboxylic acids (BCAs) is largely reported as primary or secondary organic aerosols. However, sparse studies describe the distribution of these organic compounds in fluvial and marine environments. In the context of a global warming, we present the first results of a study of the distribution of BCAs in a surface Arctic coastal area near the mouth of the Mackenzie River. These results showed that the Beaufort Sea is an area with elevated BCA content among which glyoxylic acid is predominant, in contrast to low concentrations and predominance of oxalic acid in aerosols reported elsewhere. The carbon fraction of BCAs represents 1.8% to 4.5% of dissolved organic carbon pool in Arctic Ocean. This study reinforces the hypothesis that aquatic biological processes govern the molecular distribution of BCA in marine/river waters, whereas photochemical oxidation reactions regulate their molecular distribution in rain and aerosols. Our results indicate that the Mackenzie River is an important source of BCAs in the Arctic Ocean during July–October period, with a first estimate of 35 × 103 tons of BCAs including 12 × 103 tons of diacids and 23 × 103 tons of oxoacids.

Sovereignty as an economical and geographic phenomenon (employing trends in the development of the Arctic zone of the Russian Federation)

A departure from the legal interpretation of the sovereignty of the Arctic zone of the Russian Federation allows one to draw the tools and information resources of other Sciences into studying this concept. The author believes that economic geography can make a significant contribution. An economicgeographical approach to the problem of national sovereignty in the Arctic puts it in the context of space (the sovereignty of which is questioned), which is atomized on a micro-level of municipalities (districts and cities) and rural and urban settlements. The protection of their sovereignty is connected with the implementation of investment projects, livelihood of local communities, preservation of the traditional economy and way of life, territories of traditional residence and natural use of indigenous peoples, ongoing research (stationary and expedition) activities in the territory. The author suggests an understanding of sovereignty as a process, which has a different value (which changes) in specific periods of time. This approach is illustrated by two periods in the development of the Arctic zone of the Russian Federation: 2010–2013 and 2014–2017. The first period can be called a time of “exogenous” developments, when the question of the sovereignty of the Arctic territories and waters of Russia approved in the coordinates of the active international cooperation with other Arctic countries on all possible negotiating forums. The second period saw a radical change in the entire instrumentation of Arctic sovereignty in favor of domestic investment focus on large mining and infrastructure projects, land and transition zone “land-sea” and defense mobilization in the Arctic Islands and coastal areas. Refs 17. Tables 3.

Svalbard as a study model of future High Arctic coastal environments in a warming world

Summary Svalbard archipelago, a high latitude area in a region undergoing rapid climate change, is relatively easily accessible for field research. This makes the fjords of Spitsbergen, its largest island, some of the best studied Arctic coastal areas. This paper aims at answering the question of how climatically diverse the fjords are, and how representative they are for the expected future Arctic diminishing range of seasonal sea-ice. This study uses a meteorological reanalysis, sea surface temperature climatology, and the results of a recent one-year meteorological campaign in Spitsbergen to determine the seasonal differences between different Spitsbergen fjords, as well as the sea water temperature and ice ranges around Svalbard in recent years. The results show that Spitsbergen fjords have diverse seasonal patterns of air temperature due to differences in the SST of the adjacent ocean, and different cloudiness. The sea water temperatures and ice concentrations around Svalbard in recent years are similar to what is expected most of the Arctic coastal areas in the second half of this century. This makes Spitsbergen a unique field study model of the conditions expected in future warmer High Arctic.

Biological effects of mechanically and chemically dispersed oil on the Icelandic scallop (Chlamys islandica)

This study aimed to simulate conditions in which dispersant (Dasic NS) might be used to combat an oil spill in coastal sub-Arctic water of limited depth and water exchange in order to produce input data for Net Environmental Benefit Analysis (NEBA) of Arctic and sub-Arctic coastal areas. Concentration dependent differences in acute responses and long-term effects of a 48h acute exposure to dispersed oil, with and without the application of a chemical dispersant, were assessed on the Arctic filter feeding bivalve Chlamys islandica. Icelandic scallops were exposed for 48h to a range of spiked concentrations of mechanically and chemically dispersed oil. Short-term effects were assessed in terms of lysosomal membrane stability, superoxide dismutase, catalase, gluthatione S-transferases, glutathione peroxidases, glutathione reductase, glutathione, total oxyradical scavenging capacity, lipid peroxidation and peroxisomal proliferation. Post-exposure survival, growth and reproductive investment were followed for 2 months to evaluate any long-term consequence. Generally, similar effects were observed in scallops exposed to mechanically and chemically dispersed oil. Limited short-term effects were observed after 48h, suggesting that a different timing would be required for measuring the possible onset of such effects. There was a concentration dependent increase in cumulative post-exposure mortality, but long-term effects on gonadosomatic index, somatic growth/condition factor did not differ among treatments.

Seasonal variations of phytoplankton dynamics in Nunatsiavut fjords (Labrador, Canada) and their relationships with environmental conditions

We assessed phytoplankton dynamics and its environmental control in four Labrador fjords (Nachvak, Saglek, Okak, and Anaktalak) during summer, early fall and late fall. Primary production and chlorophyll a (chl a) biomass were measured at seven optical depths, including the depth of subsurface chl a maximum (SCM). Phytoplankton abundance, size structure and taxonomy were determined at the SCM. Principal component analysis and non-metric multidimensional scaling were used to analyze relationships between production, biomass and community composition in relation to environmental variables. We observed a marked seasonal variability, with significant differences in phytoplankton structure and function between summer and fall. Surprisingly, primary production and chl a biomass were not significantly different from one fjord to another. The highest values of primary production (1730mgCm−2day−1) and chl a biomass (96mgchlam−2) were measured during the summer bloom, and those high values indicate that Labrador fjords are highly productive ecosystems. The summer community showed relatively high abundance of nanophytoplankton (2–20μm) while the fall community was characterized by low primary production and chl a biomass as well as relatively high abundance of picophytoplankton (<2μm). The low value of carbon potentially exported out of the euphotic zone throughout the study (≤31% of total primary production) suggests that phytoplankton production was mainly grazed by microzooplankton rather than being exported to greater depths. We observed a mixed assemblage of diatoms and flagellates in summer, whereas the fall community was largely dominated by flagellates. Seasonal variations in phytoplankton dynamics were mainly controlled by the strength of the vertical stratification and by the large differences in day length due to the northerly location of Labrador fjords. This study documents for the very first time phytoplankton structure and function in Labrador fjords, and provides an essential foundation for further research and for monitoring environmental changes in arctic and subarctic coastal areas.