Eutrophication in the High Arctic — Meretta Lake, Cornwallis Island (75° N Lat.)

1974 ◽  
Vol 31 (5) ◽  
pp. 647-662 ◽  
Author(s):  
D. W. Schindler ◽  
J. Kalff ◽  
H. E. Welch ◽  
G. J. Brunskill ◽  
H. Kling ◽  
...  

Sewage from the Department of Transport Airport Base at Resolute Bay has caused increases in phytoplankton standing crop, changes in algal species composition, oxygen depletion, and disappearance of Limnocalanus in Meretta Lake. The annual cycles of chemical and physical events associated with these changes are described. Minimum annual input of phosphorus to Meretta Lake was 0.24–0.29 g/m2 of lake surface per year in 1971, with 66–80% supplied by sewage. Nitrogen input was 0.55–0.78 g/m2 during the same year, with 41 to 58% from sewage. Results show that severe eutrophication problems may be expected to develop in response to high nutrient inputs, even at arctic latitudes. Arctic lakes, which are sealed under ice for several months of the year, appear to be particularly vulnerable to increased oxygen depletion which accompanies eutrophication.

2019 ◽  
Vol 5 (2) ◽  
pp. 90-106 ◽  
Author(s):  
Gretchen L. Lescord ◽  
Meredith G. Clayden ◽  
Karen A. Kidd ◽  
Jane L. Kirk ◽  
Xiaowa Wang ◽  
...  

Methylmercury (MeHg) biomagnifies through aquatic food webs resulting in elevated concentrations in fish globally. Stable carbon and nitrogen isotopes are frequently used to determine dietary sources of MeHg and to model its biomagnification. However, given the strong links between MeHg and sulfur cycling, we investigated whether sulfur isotopes (δ34S) would improve our understanding of MeHg concentrations ([MeHg]) in Arctic lacustrine food webs. Delta34S values and total mercury (THg) or MeHg were measured in water, sediments, and biota from six lakes near Resolute Bay, NU, Canada. In two lakes impacted by historical eutrophication, aqueous sulfate δ34S was ∼8‰ more positive than sedimentary δ34S, suggestive of bacterial sulfate reduction in the sediment. In addition, aqueous δ34S showed a significant positive relationship with aqueous [MeHg] across lakes. Within taxa across lakes, [THg] in Arctic char muscle and [MeHg] in their main prey, chironomids, were positively related to their δ34S values across lakes, but inconsistent relationships were found across entire food webs among lakes. Across lakes, nitrogen isotopes were better predictors of biotic [THg] and [MeHg] than δ34S within this dataset. Our results suggest some linkages between Hg and S biogeochemistry in high Arctic lakes, which is an important consideration given anticipated climate-mediated changes in nutrient cycling.


2016 ◽  
Vol 27 (S1) ◽  
pp. 191-199 ◽  
Author(s):  
Edoardo Calizza ◽  
Maria Letizia Costantini ◽  
David Rossi ◽  
Vittorio Pasquali ◽  
Giulio Careddu ◽  
...  

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
K. E. Roberts ◽  
S. F. Lamoureux ◽  
T. K. Kyser ◽  
D. C. G. Muir ◽  
M. J. Lafrenière ◽  
...  
Keyword(s):  

1976 ◽  
Vol 108 (10) ◽  
pp. 1053-1064 ◽  
Author(s):  
D. R. Oliver

AbstractPseudodiamesa arctica (Mall.), Heterotrissocladius subpilosus (Kieff.), Orthocladius (s.s.) lapponicus Goetgh., Orthocladius (s.s.) sp., Paracladius quadrinodosus Hirv., Trissocladius tricornis n. sp., and Lauterbornia sedna n. sp. develop from egg to pharate adult in Char Lake. The occurrence of the larvae of 7 additional species is apparently adventitious, All stages of the two new species plus the larvae of P. arctica and P. quadrinodosus are described. The males of T. tricornis are dimorphic and L. sedna is parthenogenetic. New distribution records are given for most of the species. The chironomid fauna of Char Lake is compared with that of other arctic lakes.


1950 ◽  
Vol 28a (5) ◽  
pp. 535-541
Author(s):  
Michael Beer

Four determinations of gravity were made during the summer of 1948, with the pendulum apparatus of the Dominion Observatory, at Goose Bay, Labrador (latitude 53°), Frobisher Bay, Baffin Island (latitude 64°), Resolute Bay, Cornwallis Island (latitude 75°), and Thule, Greenland (latitude 77°), approximately. The anomalies at the two most northerly stations are comparatively small and those at the other two stations, although larger, do not exceed many that have been observed in other parts of Canada. Norgaard's determination at Thule is confirmed by the author.It is anticipated that these determinations, apart from their immediate interest, will serve as useful reference points for future work in the Canadian Arctic.


1988 ◽  
Vol 66 (6) ◽  
pp. 1117-1128 ◽  
Author(s):  
Katharine E. Duff ◽  
John P. Smol

Twenty-six chrysophycean stomatocyst morphotypes were described from the postglacial sediments of a small, rock basin lake near Baird Inlet, Ellesmere Island. Scanning electron and light microscopy were used to classify the stomatocysts, following the guidelines of the International Statospore Working Group. None of the stomatocysts could be related with certainty to the chrysophyte species that produced them, but sufficient morphological detail is present in most of the stomatocysts to allow for taxonomic differentiation. A stratigraphic analysis of the dominant stomatocyst morphotypes revealed that chrysophyte species composition changed most markedly during the lake's early development but then remained relatively constant. This study demonstrated that chrysophycean stomatocysts provide useful paleoecological information in High Arctic lakes, but further taxonomic and ecological research is required to fully exploit these microfossils.


2020 ◽  
Vol 167 (12) ◽  
Author(s):  
Fabio Bulleri ◽  
Giuseppina Pardi ◽  
Laura Tamburello ◽  
Chiara Ravaglioli

AbstractNutrient enrichment is a major threat to subtidal macroalgal forests. Several studies have shown that nutrient inputs can enhance the ability of opportunistic algal species to acquire space freed by disturbance, at the expense of architecturally complex species that form forests. However, competition between canopy- and turf-forming macroalgae is not limited to the aftermath of disturbance. Canopy-forming macroalgae can provide suitable substratum for diverse epibiont assemblages, including both algae (epiphytes) and sessile invertebrates (epizoans). Despite evidence of enhanced epiphyte loading under eutrophic conditions, few experimental studies have assessed how nutrient enrichment influences the structure of epibiont assemblages on canopy-forming macroalgae at the edge versus inside forests. In oligotrophic waters of the NW Mediterranean, we experimentally tested the hypothesis that nutrient-driven proliferation of opportunistic epiphytic algae would affect the performance of the fucoid, Carpodesmia brachycarpa, and reduce the richness and abundance of the epizoan species they support. We predicted negative effects of nutrient enrichment to be greater at the edge than inside forests and on thalli that had recovered in cleared areas than on those within undisturbed canopy stands. Nutrient enrichment did not affect the photosynthetic efficiency and reproductive output of C. brachycarpa. By contrast, it enhanced herbivore consumption and decreased the cover and diversity of epizoans at forest edges, likely by stimulating the foraging activity of Arbacia lixula, the most abundant sea urchin in adjacent encrusting coralline barrens. Fertilization of areas inside forests had no effect on either C. brachycarpa or epibiont assemblages. Finally, nutrient enrichment effects did not vary between cleared and undisturbed areas. Our results show that moderate nutrient enrichment of oligotrophic waters does not necessarily cause the proliferation of epiphytes and, hence, a strengthening of their competitive effects on canopy-forming macroalgae. Nevertheless, enhanced herbivory damage to fertilized thalli at forest edges suggests that fragmentation could reduce the resilience of macroalgal forests and associated epibiont assemblages to nutrient enrichment.


1997 ◽  
Vol 201 (3) ◽  
pp. 171-187 ◽  
Author(s):  
Hilary Freitas ◽  
Miriam Diamond ◽  
Ray Semkin ◽  
Dennis Gregor

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