scholarly journals Dispersal limitation and climate-related environmental gradients structure microcrustacean composition in freshwater lakes, Ellesmere Island, Canada

2008 ◽  
Vol 65 (9) ◽  
pp. 1905-1918 ◽  
Author(s):  
Angela L. Strecker ◽  
Rebecca Milne ◽  
Shelley E. Arnott
Keyword(s):  
Species Richness ◽  
Environmental Change ◽  
Community Composition ◽  
Environmental Gradients ◽  
Negative Relationship ◽  
Ellesmere Island ◽  
Arctic Lakes ◽  
The Arctic ◽  
Arctic Ecosystems ◽  
Daphnia Middendorffiana

Dramatic environmental change is expected in the Arctic, yet little is known about the occurrence and community composition of microcrustaceans in Arctic lakes and how this will be influenced by future environmental change. We sampled and calculated relative abundances of microcrustacean species in 54 lakes on Ellesmere Island, Canada. New species records on Ellesmere Island included Daphnia umbra , Tachidius discipes , and Artemeopsis stefanssoni . Daphnia middendorffiana/tenebrosa was the most common taxon and often dominated microcrustacean assemblages, likely a result of its pigmentation, which offers resistance to ultraviolet radiation. Species richness was positively associated with nutrients, dissolved organic carbon (DOC), temperature, calcium, and conductivity and negatively affected by elevation. In contrast to most findings in temperate systems, we detected a negative relationship between species richness and surface area. Community composition was influenced by DOC, nutrients, and elevation but was also related to spatial variables, suggesting that spatial gradients in environmental conditions and dispersal are important drivers of differences among sites. Arctic ecosystems are expected to change rapidly in the coming years because of climate change and ozone thinning, and we expect that associated changes in DOC, temperature, and nutrients will affect microcrustacean species richness and distribution throughout the landscape.

ZOOPLANKTON OF LAKE HAZEN, ELLESMERE ISLAND, AND A NEARBY POND, WITH SPECIAL REFERENCE TO THE COPEPOD CYCLOPS SCUTIFER SARS

1964 ◽  
Vol 42 (4) ◽  
pp. 613-629 ◽  
Author(s):  
I. A. McLaren
Keyword(s):  
Special Reference ◽  
Standing Crop ◽  
Dry Weight ◽  
High Arctic ◽  
Ellesmere Island ◽  
Arctic Lakes ◽  
Net Production ◽  
Daphnia Middendorffiana ◽  
Ice Conditions ◽  
Cyclops Scutifer

Zooplankton was studied in the large, high-arctic Lake Hazen and in a small nearby pond. Primary (O2) production in Lake Hazen may have occurred largely before the ice began to melt, but was unmeasurable in summer. Primary production in the pond was about the same as in other small arctic lakes, Cyclops scutifer was overwhelmingly dominant in Lake Hazen. C. scutifer and Daphnia middendorffiana were commonest in the pond. C, scutifer is annual in Scandinavia, often with coexisting spring-born and fall-born generations. On Ellesmere Island the pond appears to contain alternating annual and biennial generations, whereas the species is strictly biennial in Lake Hazen. Numbers of C. scutifer in Lake Hazen were greatly reduced as a result of summer ice conditions between 1958 and 1961, while the rotifer Keratella hiemalis increased. Estimated mean standing crop (96 mg/m2) and net production (1.0 mg/m2 day) in dry weight ol C. scutifer in Lake Hazen during the summer of 1958 were extremely low. In early August the crop of this species in the pond was abont the same as in Lake Hazen, but net production was sonic 15 times as large, and other zooplankters added considerably to crop and production of the pond.

scholarly journals On giant shoulders: How a seamount affects the microbial community composition of seawater and sponges

2020 ◽  
Author(s):  
Kathrin Busch ◽  
Ulrike Hanz ◽  
Furu Mienis ◽  
Benjamin Müller ◽  
Andre Franke ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Dissolved Inorganic Carbon ◽  
Environmental Gradients ◽  
Microbial Community Composition ◽  
Geographic Location ◽  
Environmental Parameters ◽  
Amplicon Sequencing ◽  
The Arctic ◽  
Rrna Gene

Abstract. Seamounts represent ideal systems to study the influence and interdependency of environmental gradients at a single geographic location. These topographic features represent a prominent habitat for various forms of life, including microbiota and macrobiota, spanning benthic as well as pelagic organisms. While it is known that seamounts are globally abundant structures, it still remains unclear how and to which extend the complexity of the seafloor is intertwined with the local oceanographic mosaic, biogeochemistry and microbiology of a seamount ecosystem. Along these lines, the present study aimed to explore whether and to which extend seamounts can have an imprint on the microbial community composition of seawater and of sessile benthic invertebrates, sponges. For our high-resolution sampling approach of microbial diversity (16S rRNA gene Amplicon sequencing) along with measurements of inorganic nutrients and other biogeochemical parameters, we focused on the Schulz Bank seamount ecosystem, a sponge ground ecosystem which is located on the Arctic Mid-Ocean Ridge. Seawater samples were collected at two sampling depths (mid-water: MW, and near-bed water: BW) from a total of 19 sampling sites. With a clustering approach we defined microbial micro-habitats within the pelagic realm at Schulz Bank, which were mapped onto the seamount's topography, and related to various environmental parameters (such as suspended particulate matter (SPM), dissolved inorganic carbon (DIC), silicate (SiO4−), phosphate (PO43−), ammonia (NH4+), nitrate (NO32−), nitrite (NO2

scholarly journals Endemicity and Community Composition of Marine Species along the NW Pacific and Adjacent Arctic Ocean

2019 ◽  
Vol 3 ◽  
Author(s):  
Hanieh Saeedi ◽  
Marianna Simoes ◽  
Angelika Brandt
Keyword(s):  
Species Richness ◽  
Pacific Ocean ◽  
Arctic Ocean ◽  
Shallow Water ◽  
Community Composition ◽  
Deep Sea ◽  
Sampling Bias ◽  
The Arctic ◽  
Philippine Sea ◽  
The Arctic Ocean

The Northwestern (NW) Pacific Ocean lies in one of the most productive, speciose, and diverse regions of the World Ocean, and includes several shallow-water oceanic islands and deep-sea basins of varying depth, hydrology, and degree of isolation. The adjacent Arctic Ocean areas include the northern Bering and southern Chukchi Seas of the Arctic Ocean with short food chains and shallow depths characterizing high productivity areas. Despite its magnitude and relevance, characterization of species diversity and community composition patterns in the NW Pacific Ocean remains poorly explored and largely unknown. Here we attempt to discover how geographic boundaries and depth shape current community assemblages and delimit species distribution ranges and richness using open access data. We also show how endemicity and community composition vary between tropical and temperate NW Pacific and the adjacent Arctic Ocean considering sampling bias. The Eastern Philippine Sea was the hotspot of species richness in the NW Pacific and its adjacent Arctic Ocean even when accounting for sampling bias. The lowest species richness was observed in Papau. Despite high species richness in the Eastern Philippine Sea, the Yellow Sea and Gulf of Tonkin had the highest endemicity rates (ca. 60%) among all other ecoregions. Endemicity ranged 20–40% across 19 ecoregions. Chordata, Arthropoda, and Mollusca contributed more than 50% to the total community composition in the NW Pacific where as Arthropoda, Annelida, and Mollusca were the dominant taxa shaping ca. 82% of the Arctic Ocean community. Pelagic species richness was higher than the benthic one in both shallow-water and deep-sea regions of the NW Pacific Ocean. However, in the shallow and deep Arctic Ocean, most of the taxa were benthic excluding the deep Kara Sea where pelagic deep-sea species dominated the whole community. Two significantly distinctive clusters (North and South clusters) were classified based on species richness similarity analysis in this area including ecoregions of the (1) Arctic Ocean and North NW Pacific, and (2) Mid to South NW Pacific.

3. Arctic ecosystems

2021 ◽  
pp. 39-62
Author(s):  
Klaus Dodds ◽  
Jamie Woodward
Keyword(s):  
Environmental Change ◽  
Soil Depth ◽  
Nutrient Supply ◽  
The Arctic ◽  
High Latitudes ◽  
Arctic Ecosystems ◽  
Arctic Vegetation ◽  
Animal Populations ◽  
Key Characteristics ◽  
The Arctic Ocean

‘Arctic ecosystems’ highlights the treeless landscapes that fringe the Arctic Ocean, in which the diversity of plants is low, nutrient supply is limited, and soil depth is constrained by permafrost. The aim is to capture some of the key characteristics of the Arctic biome in the past and present. How do ecosystems function in the northern high latitudes? How have they responded to the recent environmental change? Arctic vegetation is grouped into twenty-one provinces based on various characteristics including relative uniformity of species and number of endemics. High fluctuation in animal populations is a key feature of the Arctic biome.

scholarly journals Environmental and Management Control over the Submontane Grassland Plant Communities in Central Slovakia

Diversity ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 30
Author(s):  
Andrea Diviaková ◽  
Slavomír Stašiov ◽  
Radovan Pondelík ◽  
Vladimír Pätoprstý ◽  
Milan Novikmec
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Plant Species ◽  
Negative Relationship ◽  
Floristic Composition ◽  
Diversity Management ◽  
Grassland Management ◽  
Plant Species Richness ◽  
Management Control ◽  
Grassland Species

In Central Europe, submontane grassland plant biodiversity is currently threatened by management intensification as well as by the cessation and abandonment of management activities (extensive grazing and mowing). Although the vegetation of Central European grasslands has been well described by phytosociological papers, there is still a need to improve our understanding of the effect of both management and environment on species richness and community composition. We studied submontane grassland communities in Central Slovakia. Our study showed that both environmental variables and management were important for shaping the submontane grassland species richness and floristic composition. Plant species richness showed a weak negative relationship with soil pH. When grassland management types were analyzed individually, the amount of phosphorus, nitrogen, pH, and altitude were all found to be significantly correlated with plant species richness or diversity. Management type and local environmental factors (i.e., incoming solar radiation) both determined community composition.

scholarly journals Exploring Multiple Aspects of Taxonomic and Functional Diversity in Microphytobenthic Communities: Effects of Environmental Gradients and Temporal Changes

2021 ◽  
Vol 12 ◽  
Author(s):  
Anette Teittinen ◽  
Leena Virta
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Functional Diversity ◽  
Environmental Changes ◽  
Environmental Gradients ◽  
Temporal Variations ◽  
The Face ◽  
Functional Dispersion ◽  
Pool System ◽  
Microbial Groups

Biodiversity has traditionally been quantified using taxonomic information but the importance of also considering its functional characteristics has recently gained an increasing attention among microorganisms. However, studies exploring multiple aspects of taxonomic and functional diversity and their temporal variations are scarce for diatoms, which is one of the most important microbial groups in aquatic ecosystems. Here, our aim was to examine the taxonomic and functional alpha and beta diversities of diatoms in a coastal rock pool system characterized by a naturally high environmental heterogeneity. We also investigated the temporal differences in the diversity patterns and drivers. The relationship between the species richness and functional dispersion was temporally coherent, such that species-poor communities tended to be functionally clustered. The trend between the species richness and taxonomic uniqueness of community composition was temporally inconsistent, changing from negative to non-significant over time. Conductivity or distance to the sea or both were key determinants of species richness, functional dispersion, and uniqueness of community composition. The increase of community dissimilarity with an increasing environmental distance was stronger for the taxonomic than the functional composition. Our results suggest that even minor decreases in the species richness may result in a lowered functional diversity and decreased ecosystem functioning. Species-poor ecosystems may, however, have unique species compositions and high contributions to regional biodiversity. Despite changing the species compositions along the environmental gradients, communities may remain to have a high functional similarity and robustness in the face of environmental changes. Our results highlight the advantage of considering multiple biodiversity metrics and incorporating a temporal component for a deeper understanding of the effects of environmental changes on microbial biodiversity.

Effects of fertilization on three tundra plant communities of a polar desert oasis

1986 ◽  
Vol 64 (11) ◽  
pp. 2502-2507 ◽  
Author(s):  
G. H. R. Henry ◽  
B. Freedman ◽  
J. Svoboda
Keyword(s):  
Plant Communities ◽  
High Arctic ◽  
Ellesmere Island ◽  
Nutrient Addition ◽  
The Arctic ◽  
Arctic Ecosystems ◽  
Polar Desert ◽  
Net Production ◽  
Dwarf Shrubs ◽  
Desert Oasis

Three plant communities studied at a high arctic oasis on Ellesmere Island responded to nutrient addition. Response to nitrogen was greatest in the driest community and weaker in the more mesic and wet-mesic communities. Nutrient addition resulted in (i) increased inflorescence densities of dicotyledonous and certain graminoid species; (ii) increased tiller densities of wet sedge species; and (iii) increased net production of graminoids and forbs at high rates of application, and in some dwarf shrubs at lower rates. These results parallel those of studies at lower latitudes in the Arctic, and support the hypothesis that arctic ecosystems are typically oligotrophic.

scholarly journals Richness and phylogenetic diversity are affected by space and time in the megadiverse Atlantic Forest of South America

2018 ◽  
Author(s):  
José Thales da Motta Portillo ◽  
Fausto Erritto Barbo ◽  
Josué Anderson Rêgo Azevedo ◽  
Ricardo Jannini Sawaya
Keyword(s):  
Species Richness ◽  
South America ◽  
Atlantic Forest ◽  
Phylogenetic Diversity ◽  
Latitudinal Gradient ◽  
Environmental Gradients ◽  
Negative Relationship ◽  
Latitudinal Gradients ◽  
Tropical Regions ◽  
The Tropics

Understanding variation of species richness along latitudinal gradients, with more species toward the tropics, represents a challenge for ecologists. Species richness also varies according to the available area, with more species in larger regions, with area and latitude posited as major drivers of richness variations. However, species richness does not fully capture the evolutionary history behind those patterns. Phylogenetic diversity can provide insights on the role of time and evolutionary drivers of environmental gradients. We analyzed here the latitudinal gradient of endemic snakes from the Atlantic Forest of South America, a megadiverse and highly threatened portion of the Neotropics. We assessed the effect of area and average clade age on species richness and phylogenetic diversity, testing whether species richness and phylogenetic diversity increase with area availability and in lower latitudes. We found that area can predict species richness, but not phylogenetic diversity. Brazilian southeastern mountain ranges include larger patches of Atlantic Forest and the highest richness levels, but generally harboring snakes from relatively recent clades (neoendemics). There is a negative relationship between species richness and average clade age along the latitudinal gradient, with older clades found mainly in northern portions, increasing phylogenetic diversity at lower latitudes. Different dimensions of diversity, species richness and phylogenetic diversity, are thus affected in different ways by area and time for speciation in the Atlantic Forest, and this may be a trend in highly diverse tropical regions.

scholarly journals Essai: Is Arctic Palynology a “Blunt Instrument”?

2007 ◽  
Vol 60 (2) ◽  
pp. 95-102 ◽  
Author(s):  
Konrad Gajewski
Keyword(s):  
Environmental Change ◽  
Spatial Resolution ◽  
The Arctic ◽  
Arctic Ecosystems ◽  
Temporal And Spatial ◽  
Pollen Analyses ◽  
The Way

AbstractFor nearly forty years, palynologists and other scientists studying the Quaternary have claimed that palynology, when applied in the Arctic, is a “blunt instrument” for analysing environmental change in this region. In this essay, the author explains why this expression should be laid to rest. Limits to palynological resolution are spatial, temporal and taxonomic. These are discussed and examples are shown where both the temporal and spatial resolution of pollen analyses is far higher than previously thought possible. The supposed “bluntness” of Arctic palynology is due to the way this tool has been applied in Arctic environments rather than inherent limits of palynology in Arctic ecosystems.

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