Life cycles and population dynamics of enchytraeids (Oligochaeta) from the High Arctic

2000 ◽  
Vol 78 (12) ◽  
pp. 2079-2086 ◽  
Author(s):  
T Birkemoe ◽  
S J Coulson ◽  
L Sømme
Keyword(s):  
Population Dynamics ◽  
High Arctic ◽  
Early Summer ◽  
Life Cycles ◽  
The Arctic ◽  
Adult Size ◽  
Numerous Species ◽  
Summer Temperatures ◽  
First Time ◽  
Mature Size

We report the results of the first study of the population dynamics and life cycles of Arctic enchytraeid populations. Sampling was undertaken in a Salix heath in Adventdalen, Svalbard, during one summer and the succeeding spring. In addition, a Cassiope heath at a more northerly site close to Ny-Ålesund, Svalbard, was sampled twice. The Arctic enchytraeids were generally smaller at maturity than their temperate-zone relatives. The three most numerous species in the Salix heath, Henlea perpusilla, Henlea glandulifera, and Bryodrilus parvus, hatched from cocoons in early summer and attained adult size early in their second summer. A few H. perpusilla and H. glandulifera reached mature size in their first summer; since the summer of investigation was unusually cold, these species may have a 1-year life cycle in warmer years. Life cycles were apparently longer in the Cassiope heath than in the Salix heath. Henlea perpusilla, H. glandulifera, and B. parvus produced eggs throughout the summer in the Salix heath, though hatching was restricted to early summer. Therefore, the hypothesis that cocoons require a cold period to hatch was tested in a laboratory experiment. When soil containing cocoons was incubated at -5°C for 3 weeks, a significant increase in juveniles was demonstrated for H. perpusilla and Bryodrilus diverticulatus compared with soils kept at constant summer temperatures. This is the first time that breaking of dormancy by an external stimulus has been demonstrated in enchytraeid cocoons.

scholarly journals Density, snow, and seasonality lead to variation in muskox (Ovibos moschatus) habitat selection during summer

2019 ◽  
Vol 97 (11) ◽  
pp. 997-1003
Author(s):  
Orlando Tomassini ◽  
Floris M. van Beest ◽  
Niels M. Schmidt
Keyword(s):  
Population Dynamics ◽  
Habitat Selection ◽  
Environmental Conditions ◽  
Census Data ◽  
High Arctic ◽  
Early Summer ◽  
The Arctic ◽  
Selection Strategy ◽  
Ovibos Moschatus ◽  
Arctic Summer

Understanding how environmental conditions influence habitat selection and suitability of free-ranging animals is critical, as the outcome may have implications for individual fitness and population dynamics. Density and snow are among the most influential environmental conditions driving habitat-selection patterns of northern ungulates. We used two decades of census data from high Arctic Greenland to quantify inter- and intra-annual variations in muskox (Ovibos moschatus (Zimmermann, 1780)) habitat selection and suitability during the Arctic summer (July through October). Across years, habitat selection varied considerably, and the strength of habitat selection appeared negatively related to both muskox density and spring snow cover. In early summer, habitat suitability was high and spatially rather uniform. Towards the autumn, suitable habitats contracted to just the lower elevations, when muskoxen exhibited increasingly stronger habitat selection towards low elevations and dense vegetation. This selection strategy clearly reflects the need to build up fat reserves for the upcoming winter, highlighting the energetic importance of the Arctic summer. Extreme climatic events such as freezing rain in autumn are increasing in frequency in Greenland and limit muskox access to high-quality forage in fens. Such events may therefore negatively affect the energy acquisition process of muskox with potential cascading consequences on population dynamics.

scholarly journals Arctic tidal characteristics at Eureka (80° N, 86° W) and Svalbard (78° N, 16° E) for 2006/07: seasonal and longitudinal variations, migrating and non-migrating tides

2009 ◽  
Vol 27 (3) ◽  
pp. 1153-1173 ◽  
Author(s):  
A. H. Manson ◽  
C. E. Meek ◽  
T. Chshyolkova ◽  
X. Xu ◽  
T. Aso ◽  
...  
Keyword(s):  
High Arctic ◽  
Early Summer ◽  
Planetary Waves ◽  
Diurnal Tide ◽  
The Arctic ◽  
Meteor Radar ◽  
Atmospheric Propagation ◽  
Wave Numbers ◽  
The Antarctic ◽  
Abstract Operation

Abstract. Operation of a Meteor Radar at Eureka, Ellesmere Island (80° N, 86° W) began in February 2006. The first 12 months of wind data (82–97 km) are combined with winds from the Adventdalen, Svalbard Island (78° N, 16° E) Meteor Radar to provide the first contemporaneous longitudinally spaced observations of mean winds, tides and planetary waves at such high Arctic latitudes. Unique polar information on diurnal non-migrating tides (NMT) is provided, as well as complementary information to that existing for the Antarctic on the semidiurnal NMT. Zonal and meridional monthly mean winds differed significantly between Canada and Norway, indicating the influence of stationary planetary waves (SPW) in the Arctic mesopause region. Both diurnal (D) and semi-diurnal (SD) winds also demonstrated significantly different magnitudes at Eureka and Svalbard. Typically the D tide was larger at Eureka and the SD tide was larger at Svalbard. Tidal amplitudes in the Arctic were also generally larger than expected from extrapolation of high mid-latitude data. For example time-sequences from ~90 km showed D wind oscillations at Eureka of 30 m/s in February–March, and four day bursts of SD winds at Svalbard reached 40 m/s in June 2006. Fitting of wave numbers for the migrating and non-migrating tides (MT, NMT) successfully determines dominant tides for each month and height. For the diurnal tide, NMT with s=0, +2 (westward) dominate in non-summer months, while for the semi-diurnal tide NMT with s=+1, +3 occur most often during equinoctial or early summer months. These wave numbers are consistent with stationary planetary wave (SPW)-tidal interactions. Assessment of the global topographic forcing and atmospheric propagation of the SPW (S=1, 2) suggests these winter waves of the Northern Hemisphere are associated with the 78–80° N diurnal NMT, but that the SPW of the Southern Hemisphere winter have little influence on the summer Arctic tidal fields. In contrast the large SPW and NMT of the Arctic winter may be associated, consistent with Antarctic observations, with the observed occurrence of the semidiurnal NMT in the Antarctic summer.

Life cycles of four species of Pseudocalanus in Nova Scotia

1989 ◽  
Vol 67 (3) ◽  
pp. 552-558 ◽  
Author(s):  
I. A. McLaren ◽  
Estelle Laberge ◽  
C. J. Corkett ◽  
J.-M. Sévigny
Keyword(s):  
Life Cycle ◽  
Nova Scotia ◽  
First Generation ◽  
Early Summer ◽  
Life Cycles ◽  
The Arctic ◽  
Late Winter ◽  
Early Winter ◽  
Temperature Dependent ◽  
Scotian Shelf

The primarily arctic Pseudocalanus acuspes, relict in Bedford Basin, Nova Scotia, produces a first generation (G1) in late winter; most G1 individuals mature in late spring. The G1 then produces a G2, most of which "rest" in copepodite stages III and IV until early winter. These stages store large amounts of lipid in early summer, which slowly diminish subsequently. A small number of G2 individuals continue to develop at temperature-dependent rates, maturing in early autumn and producing G3 adults in November. Copepodites developing in winter and spring store less lipid. The primarily arctic Pseudocalanus minutus, rare in Bedford Basin and on the Scotia Shelf, is strictly annual, developing to a lipid-filled copepodite stage V after spawning in late winter. The arctic–temperate Pseudocalanus newmani is abundant on the Scotian Shelf, but may not be self-sustaining when advected into Bedford Basin. It stores little lipid and appears to have at least three mature generations at temperature-dependent intervals over Browns Bank between May and November. It may rest in winter, or its life-cycle synchrony by spring could result from food-limited development during winter. The temperate Pseudocalanus moultoni appears to have a life cycle similar to that of P. newmani, but was less common during summer on Browns Bank. These life cycles are appropriately adapted to the geographical ranges of the species, and show some parallels with species of Calanus.

scholarly journals Taxonomic, temporal, and spatial variation in the dynamics of High-Arctic arthropod populations

2020 ◽  
Author(s):  
Toke T. Høye ◽  
Sarah Loboda ◽  
Amanda M. Koltz ◽  
Mark A. K. Gillespie ◽  
Joseph J. Bowden ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Temporal Trends ◽  
Monitoring Program ◽  
High Arctic ◽  
The Arctic ◽  
Taxonomic Resolution ◽  
Ecosystem Functions ◽  
Series Data ◽  
Global Changes ◽  
Apparent Lack

ABSTRACTTime-series data on arthropod populations are critical for understanding the magnitude, direction, and drivers of abundance changes. However, most arthropod monitoring programs are short-lived and limited in taxonomic resolution and spatial extent. Consequently, variation in population dynamics among taxa and habitats remains poorly understood. Monitoring data from the Arctic are particularly underrepresented, yet important to assessments of species abundance changes because many anthropogenic drivers of change that are present in other regions are absent in polar regions. Here, we utilise 24 years of abundance data from Zackenberg in High-Arctic Greenland, which is the longest running Arctic arthropod monitoring program, to study temporal trends in abundance. Despite a strong warming signal in air temperature, we only find evidence of weak temporal trends in arthropod abundances across most taxa. These trends are more pronounced in the most recent decade, with change point analyses suggesting distinct non-linear dynamics within some functional groups such as predators and detritivores. Although the abundances of many taxa were correlated, we detected both positive and negative correlations, suggesting that multiple processes are affecting arthropod populations even in this relatively simple Arctic food web. Finally, we found clear differences among species within single families of arthropods, indicating that an apparent lack of change in abundance at broader taxonomic or functional levels could mask substantial species-specific trends. Our results reiterate the need for more basic research into the life-history, ecology, and adaptation of arthropod species to better understand their sensitivity to global changes.Significance statementTerrestrial arthropods, including insects and spiders, serve critical ecosystem functions and are excellent indicators of environmental change due to their physiology, short generation time, and abundance. The Arctic, with its rapid climate change and limited direct anthropogenic impact, is ideal for examining arthropod population dynamics. We use the most comprehensive, standardized dataset available on Arctic arthropods to evaluate the variability in population dynamics for the most common arthropod groups at various taxonomic levels across 24 years. Our results highlight that temporal trends of arthropod populations seem less directional in the Arctic than in temperate regions. Although abundances of some arthropod taxa are declining, particularly in recent decades, population trends still display high variation among time periods, taxa, and habitats.

scholarly journals Data on the fauna of thrips (Insecta: Thysanoptera) of trees and shrubs in Kaliningrad Region, Russia

2019 ◽  
Author(s):  
В.И. Рожина
Keyword(s):  
Species Richness ◽  
Common Species ◽  
Early Summer ◽  
Flowering Plants ◽  
Numerous Species ◽  
Frequent Species ◽  
Thrips Species ◽  
Kaliningrad Region ◽  
First Time ◽  
Trees And Shrubs

По результатам исследования представлены данные о видах трипсов (Thysanoptera), собранных с деревьев и кустарников в Калининградской области в 2013 2018 гг. Всего собрано 33 вида трипсов, из них 15 видов указаны впервые для Калининградской области (Aeolothripsericae, Ae. versicolor, Ae. melaleucus, Mycterothrips latus, Neohydаthrips gracilicornis, Oxythrips ajugae, Ox. bicolor, Taeniothrips inconsequens, Thrips calcaratus, Th. minutissimus, Th. sambuci, Haplothrips subtilissimus, Hoploandrothrips bidens, Treherniella inferna, Xylaplothrips fuliginosus). Большинство выявленных видов антофаги (42), дендробионтные филлофаги составляют 24. Собственно дендробионтных видов выявлено 13, что составляет 39 от общего числа видов. На цветущих растениях самым распространенным видом оказался Th. major. Этот вид выявлен в 65 образцах, на растениях из девяти семейств. Вторым по встречаемости оказался Th. fuscipennis он выявлен в 15 образцах из семи семейств. Весной и в начале лета на вегетирующих нецветущих растениях самым распространённым и многочисленным видом трипсов является Th. minutissimus он выявлен на растениях из шести семейств. Наибольшим видовым богатством трипсов отличаются представители семейств Rosaceae и Adoxaceae. The study presents data on the species of thrips (Thysanoptera) collected from trees and bushes in the Kaliningrad region in 2013 2018. Thirtythree species of thrips were collected. Fifteen species are recorded for the first time in the Kaliningrad region: Aeolothrips ericae, Ae. versicolor, Ae. melaleucus, Mycterothrips latus, Neohydаthrips gracilicornis, Oxythrips ajugae, Ox. bicolor, Taeniothrips inconsequens, Thrips calcaratus, Th. minutissimus, Th. sambuci, Haplothrips subtilissimus, Hoploandrothrips bidens, Treherniella inferna, Xylaplothrips fuliginosus. Most of the identified species are phytophagous (79). Alltogether, 13 species (39) of identified thrips are dendrobiont. The dendrobiont phyllophagous species comprised 24 of all species collected. The most common species on flowering plants was Th. major. This species was found on plants of 9 families. Thrips fuscipennis was the second most frequent species, it was found on plants from 7 families. In spring and early summer, the most common and numerous species on vegetating nonflowering plants is Th. minutissimus: it was identified on plants from 6 families. Representatives of Rosaceae and Adoxaceae families are remarkable in thrips species richness.

scholarly journals High gas-phase mixing ratios of formic and acetic acid in the High Arctic

2018 ◽  
Author(s):  
Emma L. Mungall ◽  
Jonathan P. D. Abbatt ◽  
Jeremy J. B. Wentzell ◽  
Gregory R. Wentworth ◽  
Jennifer G. Murphy ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Transport Model ◽  
High Arctic ◽  
Early Summer ◽  
The Arctic ◽  
Chemical Transport Model ◽  
Phase Measurements ◽  
Diurnal Cycles ◽  
Mixing Ratios

Abstract. Formic and acetic acid are ubiquitous and abundant in the Earth's atmosphere and are important contributors to cloud water acidity, especially in remote regions. Their global sources are not well understood, as evidenced by the inability of models to reproduce the magnitude of measured mixing ratios, particularly at high northern latitudes. The scarcity of measurements at those latitudes is also a hindrance to understanding these acids and their sources. Here, we present ground-based gas-phase measurements of formic acid (FA) and acetic acid (AA) in the Canadian Arctic collected at 0.5 Hz with a high resolution chemical ionization time-of-flight mass spectrometer using the iodide reagent ion (Iodide HR-ToF-CIMS, Aerodyne). This study was conducted at Alert, Nunavut, in the early summer of 2016. FA and AA mixing ratios for this period show high temporal variability and occasional excursions to very high values (up to 11 and 40 ppbv respectively). High levels of FA and AA were observed under two very different conditions: under overcast, cold conditions during which physical equilibrium partitioning should not favour their emission, and during warm and sunny periods. During the latter, sunny periods, the FA and AA mixing ratios also displayed diurnal cycles in keeping with a photochemical source near the ground. These observations highlight the complexity of the sources of FA and AA, and suggest that current chemical transport model implementations of the sources of FA and AA in the Arctic may be incomplete.

scholarly journals High gas-phase mixing ratios of formic and acetic acid in the High Arctic

2018 ◽  
Vol 18 (14) ◽  
pp. 10237-10254 ◽  
Author(s):  
Emma L. Mungall ◽  
Jonathan P. D. Abbatt ◽  
Jeremy J. B. Wentzell ◽  
Gregory R. Wentworth ◽  
Jennifer G. Murphy ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Transport Model ◽  
High Arctic ◽  
Early Summer ◽  
The Arctic ◽  
Chemical Transport Model ◽  
Phase Measurements ◽  
Diurnal Cycles ◽  
Mixing Ratios

Abstract. Formic and acetic acid are ubiquitous and abundant in the Earth's atmosphere and are important contributors to cloud water acidity, especially in remote regions. Their global sources are not well understood, as evidenced by the inability of models to reproduce the magnitude of measured mixing ratios, particularly at high northern latitudes. The scarcity of measurements at those latitudes is also a hindrance to understanding these acids and their sources. Here, we present ground-based gas-phase measurements of formic acid (FA) and acetic acid (AA) in the Canadian Arctic collected at 0.5 Hz with a high-resolution chemical ionization time-of-flight mass spectrometer using the iodide reagent ion (iodide HR-ToF-CIMS, Aerodyne). This study was conducted at Alert, Nunavut, in the early summer of 2016. FA and AA mixing ratios for this period show high temporal variability and occasional excursions to very high values (up to 11 and 40 ppbv respectively). High levels of FA and AA were observed under two very different conditions: under overcast, cold conditions during which physical equilibrium partitioning should not favor their emission, and during warm and sunny periods. During the latter, sunny periods, the FA and AA mixing ratios also displayed diurnal cycles in keeping with a photochemical source near the ground. These observations highlight the complexity of the sources of FA and AA, and suggest that current chemical transport model implementations of the sources of FA and AA in the Arctic may be incomplete.

SEASONAL EMERGENCE OF SOME HIGH ARCTIC CHIRONOMIDAE (DIPTERA)

1972 ◽  
Vol 104 (5) ◽  
pp. 661-686 ◽  
Author(s):  
H. V. Danks ◽  
D. R. Oliver
Keyword(s):  
Adult Emergence ◽  
High Arctic ◽  
Life Cycles ◽  
The Arctic ◽  
Emergence Period ◽  
Arctic Species ◽  
Chironomid Species ◽  
Annual Total ◽  
Shallow Ponds ◽  
Deep Site

AbstractThe annual emergence of 11 chironomid species from more or less shallow ponds in the area of Hazen Camp (81°49′ N., 71°18′ W.) is considered. Features of emergence are very similar in all these arctic species, although different species emerge at slightly different times in the same habitat.In the deeper habitats, emergence from a deep site is slightly later than that from a shallower one in the same pond. There are very marked differences in times of emergence from pond to pond: emergence of 50% of the annual total for a given species may be reached in different ponds up to 3 weeks apart. These differences from habitat to habitat mean that adults are present over the general Hazen area throughout the arctic summer.The time at which emergence begins in a given pond (or given site within a deeper pond) is primarily dictated by the temperature required for pre-emergence development, but also by other features of individual ponds. Pond temperatures near 4° or 5 °C are most important in this respect. The time of first emergence differs between years in the same pond according to year-to-year temperature differences.Emergence of a given species is basically highly synchronized within a pond, but the emergence period may be prolonged by lowered temperatures acting as a threshold for adult emergence at about 7 °C. The emergence pattern is less regular in shallow ponds in which the temperature fluctuates greatly, and it is more regular with lower peaks in deeper ponds.Males of a number of species generally emerge slightly before the females.Emergence of given species within given ponds is synchronized because only larvae which are ready to pupate without further feeding in spring emerge in any year. There must therefore be control of a ’diapause’ type.Aquatic insect species are characterized as ’absolute spring species’ if all potential émergents overwinter as mature larvae (i.e. larvae in which no further growth is necessary before emergence) and also ’diapause’ is present at this stage. To this category all of these high arctic species belong. They are apparently derived from ’absolute spring species’ farther south, the life-cycles of which are pre-adapted to the shortness of the arctic season. Despite the potential for highly synchronized emergence which such species possess, this potential is not fully realized in the arctic because the irregular fluctuations of temperature there operate near values which may directly inhibit development and emergence.

Persistence of giants: population dynamics of the limpet Scutellastra laticostata on rocky shores in Western Australia

2020 ◽  
Vol 646 ◽  
pp. 79-92
Author(s):  
RE Scheibling ◽  
R Black
Keyword(s):  
Population Dynamics ◽  
Western Australia ◽  
Size Structure ◽  
Survival Rates ◽  
Maximum Size ◽  
High Rate ◽  
Adult Survival ◽  
Rocky Shores ◽  
Adult Size ◽  
Decadal Time Scale

Population dynamics and life history traits of the ‘giant’ limpet Scutellastra laticostata on intertidal limestone platforms at Rottnest Island, Western Australia, were recorded by interannual (January/February) monitoring of limpet density and size structure, and relocation of marked individuals, at 3 locations over periods of 13-16 yr between 1993 and 2020. Limpet densities ranged from 4 to 9 ind. m-2 on wave-swept seaward margins of platforms at 2 locations and on a rocky notch at the landward margin of the platform at a third. Juvenile recruits (25-55 mm shell length) were present each year, usually at low densities (<1 m-2), but localized pulses of recruitment occurred in some years. Annual survival rates of marked limpets varied among sites and cohorts, ranging from 0.42 yr-1 at the notch to 0.79 and 0.87 yr-1 on the platforms. A mass mortality of limpets on the platforms occurred in 2003, likely mediated by thermal stress during daytime low tides, coincident with high air temperatures and calm seas. Juveniles grew rapidly to adult size within 2 yr. Asymptotic size (L∞, von Bertalanffy growth model) ranged from 89 to 97 mm, and maximum size from 100 to 113 mm, on platforms. Growth rate and maximum size were lower on the notch. Our empirical observations and simulation models suggest that these populations are relatively stable on a decadal time scale. The frequency and magnitude of recruitment pulses and high rate of adult survival provide considerable inertia, enabling persistence of these populations in the face of sporadic climatic extremes.

Summer phytoplankton of the northern Barents Sea (75–80º N)

2019 ◽  
pp. 8-19
Author(s):  
Larisa A. Pautova ◽  
Vladimir A. Silkin ◽  
Marina D. Kravchishina ◽  
Valeriy G. Yakubenko ◽  
Anna L. Chultsova
Keyword(s):  
Barents Sea ◽  
Weighted Average ◽  
Arctic Basin ◽  
High Arctic ◽  
Alexandrium Tamarense ◽  
Warm Water ◽  
The Arctic ◽  
Absolute Maximum ◽  
Deep Trench ◽  
Maximum Biomass

The structure of the summer planktonic communities of the Northern part of the Barents sea in the first half of August 2017 were studied. In the sea-ice melting area, the average phytoplankton biomass producing upper 50-meter layer of water reached values levels of eutrophic waters (up to 2.1 g/m3). Phytoplankton was presented by diatoms of the genera Thalassiosira and Eucampia. Maximum biomass recorded at depths of 22–52 m, the absolute maximum biomass community (5,0 g/m3) marked on the horizon of 45 m (station 5558), located at the outlet of the deep trench Franz Victoria near the West coast of the archipelago Franz Josef Land. In ice-free waters, phytoplankton abundance was low, and the weighted average biomass (8.0 mg/m3 – 123.1 mg/m3) corresponded to oligotrophic waters and lower mesotrophic waters. In the upper layers of the water population abundance was dominated by small flagellates and picoplankton from, biomass – Arctic dinoflagellates (Gymnodinium spp.) and cold Atlantic complexes (Gyrodinium lachryma, Alexandrium tamarense, Dinophysis norvegica). The proportion of Atlantic species in phytoplankton reached 75%. The representatives of warm-water Atlantic complex (Emiliania huxleyi, Rhizosolenia hebetata f. semispina, Ceratium horridum) were recorded up to 80º N, as indicators of the penetration of warm Atlantic waters into the Arctic basin. The presence of oceanic Atlantic species as warm-water and cold systems in the high Arctic indicates the strengthening of processes of “atlantificacion” in the region.

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