Species Diversity of Littoral Zone Fishes Along a Phosphorus–Production Gradient in Lake Memphremagog, Quebec–Vermont

1977 ◽  
Vol 34 (1) ◽  
pp. 167-170 ◽  
Author(s):  
Brian S. Nakashima ◽  
Dominique Gascon ◽  
William C. Leggett
Keyword(s):  
Species Diversity ◽  
Primary Production ◽  
Littoral Zone ◽  
Fish Communities ◽  
Fish Biomass ◽  
The North ◽  
Northern Areas ◽  
Phosphorus Production ◽  
South Axis

The species diversity of littoral zone fish communities in four areas of Lake Memphremagog was positively related to known phosphorus and primary production gradients along the north–south axis of the lake and to the associated north–south differences in macrobenthic and fish biomass. The highest diversity values were found consistently in the highly productive southern areas of the lake and the lowest values in the least productive northern areas.

Assessing the Interdependence of Assemblages from Rainy Lake Fisheries Data

1993 ◽  
Vol 50 (2) ◽  
pp. 402-409 ◽  
Author(s):  
Yosef Cohen ◽  
Paul Radomski ◽  
Ron Moen
Keyword(s):  
Species Diversity ◽  
Species Interactions ◽  
Yellow Perch ◽  
Function Analysis ◽  
Fish Communities ◽  
Role Reversal ◽  
Population Fluctuations ◽  
Catch Per Unit Effort ◽  
Large Lakes ◽  
The North

We applied ad hoc methods to quantify differences among fish communities in four different locations in Rainy Lake using data from index netting from long-term studies. Our analysis addressed problems of inconsistencies in data collection. We established the amount of differences and similarities among the communities by analyzing species diversity over time, utilizing matrices of partial correlations and discriminant function analysis. We also identified role reversal, i.e. synchronization in fluctuations of relative catch-per-unit-effort (CUE) between pairs of species in these communities. In the less disturbed communities, walleye (Stizostedion vitreum) contributed most to the synchronization in the fluctuations of the yearly relative CUE among six common species. In the more disturbed locations, this contribution was primarily due to yellow perch (Perca flavescens) and sauger (Stizostedion canadense). The disturbed community in one location (the North Arm) exhibited marked decrease in species diversity. Recent restrictions on the fisheries in the North Arm resulted in an increase in species diversity. Fish communities, particularly in large lakes, may differ in the detail of species interactions and population fluctuations among locations within the lake. These differences must be taken into account in analysis and management of fisheries.

The Marine Environment

2017 ◽  
Author(s):  
N. Penny Holliday ◽  
Stephanie Henson
Keyword(s):  
Primary Production ◽  
North Atlantic ◽  
Physical Environment ◽  
Seasonal Cycle ◽  
Physical Processes ◽  
The North ◽  
Basin Scale ◽  
The North Atlantic ◽  
Physical Features ◽  
Growth Distribution

The growth, distribution, and variability of phytoplankton populations in the North Atlantic are primarily controlled by the physical environment. This chapter provides an overview of the regional circulation of the North Atlantic, and an introduction to the key physical features and processes that affect ecosystems, and especially plankton, via the availability of light and nutrients. There is a natural seasonal cycle in primary production driven by physical processes that determine the light and nutrient levels, but the pattern has strong regional variations. The variations are determined by persistent features on the basin scale (e.g. the main currents and mixed layer regimes of the subtropical and subpolar gyres), as well as transient mesoscale features such as eddies and meanders of fronts.

scholarly journals A high-resolution solar spectrum 2000 Å–2200 Å

1970 ◽  
Vol 36 ◽  
pp. 271-273
Author(s):  
B. B. Jones ◽  
B. C. Boland ◽  
R. Wilson ◽  
S. T. F. Engstrom
Keyword(s):  
High Resolution ◽  
Solar Spectrum ◽  
Solar Image ◽  
Roll Control ◽  
North East ◽  
The North ◽  
Alignment System ◽  
Optical Alignment ◽  
South Axis ◽  
System Operating

A high-resolution solar spectrum in the range 2000–2200 Å was obtained in a recent flight of a sunpointing Skylark rocket. This was launched at 04.21 hr UT on April 22, 1969 from Woomera and reached an apogee of 178 km. An optical alignment system operating on the main vehicle pointing system gave a net stabilisation of ±3 arc sec in the position of the solar image relative to the spectrograph slit. The slit, of length 1.0 mm, was set in the north-east quadrant parallel to and 5 arc min from the north/south axis, its lower edge being 1 arc min from the equator. The roll control of ±2.5° was provided entirely by the standard Elliott Bros. type of vehicle stabilisation.

scholarly journals Toward a global reference database of COI barcodes for marine zooplankton

2021 ◽  
Vol 168 (6) ◽  
Author(s):  
Ann Bucklin ◽  
Katja T. C. A. Peijnenburg ◽  
Ksenia N. Kosobokova ◽  
Todd D. O’Brien ◽  
Leocadio Blanco-Bercial ◽  
...  
Keyword(s):  
Species Diversity ◽  
Dna Sequences ◽  
Reference Sequence ◽  
Global Ocean ◽  
Reference Database ◽  
Data Repositories ◽  
Marine Zooplankton ◽  
The North ◽  
Coi Sequences ◽  
Taxonomic Groups

AbstractCharacterization of species diversity of zooplankton is key to understanding, assessing, and predicting the function and future of pelagic ecosystems throughout the global ocean. The marine zooplankton assemblage, including only metazoans, is highly diverse and taxonomically complex, with an estimated ~28,000 species of 41 major taxonomic groups. This review provides a comprehensive summary of DNA sequences for the barcode region of mitochondrial cytochrome oxidase I (COI) for identified specimens. The foundation of this summary is the MetaZooGene Barcode Atlas and Database (MZGdb), a new open-access data and metadata portal that is linked to NCBI GenBank and BOLD data repositories. The MZGdb provides enhanced quality control and tools for assembling COI reference sequence databases that are specific to selected taxonomic groups and/or ocean regions, with associated metadata (e.g., collection georeferencing, verification of species identification, molecular protocols), and tools for statistical analysis, mapping, and visualization. To date, over 150,000 COI sequences for ~ 5600 described species of marine metazoan plankton (including holo- and meroplankton) are available via the MZGdb portal. This review uses the MZGdb as a resource for summaries of COI barcode data and metadata for important taxonomic groups of marine zooplankton and selected regions, including the North Atlantic, Arctic, North Pacific, and Southern Oceans. The MZGdb is designed to provide a foundation for analysis of species diversity of marine zooplankton based on DNA barcoding and metabarcoding for assessment of marine ecosystems and rapid detection of the impacts of climate change.

scholarly journals Spatiotemporal Distribution of PM2.5 and O3 and Their Interaction During the Summer and Winter Seasons in Beijing, China

2018 ◽  
Vol 10 (12) ◽  
pp. 4519 ◽  
Author(s):  
Hui Zhao ◽  
Youfei Zheng ◽  
Chen Li
Keyword(s):  
Traffic Monitoring ◽  
Diurnal Variations ◽  
Quality Monitoring ◽  
Air Quality Monitoring ◽  
Spatiotemporal Variations ◽  
Spatial Trend ◽  
The North ◽  
Northern Areas ◽  
Beijing China ◽  
Pm2.5 Concentration

This study analyzed the spatiotemporal variations in PM2.5 and O3, and explored their interaction in the summer and winter seasons in Beijing. To this aim, hourly PM2.5 and O3 data for 35 air quality monitoring sites were analyzed during the summer and winter of 2016. Results suggested that the highest PM2.5 concentration and the lowest O3 concentration were observed at traffic monitoring sites during the two seasons. A statistically significant (p < 0.05) different diurnal variation of PM2.5 was observed between the summer and winter seasons, with higher concentrations during daytime summer and nighttime winter. Diurnal variations of O3 concentrations during the two seasons showed a single peak, occurring at 16:00 and 15:00 in summer and winter, respectively. PM2.5 presented a spatial pattern with higher concentrations in southern Beijing than in northern areas, particularly evident during wintertime. On the contrary, O3 concentrations presented a decreasing spatial trend from the north to the south, particularly evident during summer. In addition, we found that PM2.5 concentrations were positively correlated (p < 0.01, r = 0.57) with O3 concentrations in summer, but negatively correlated (p < 0.01, r = −0.72) with O3 concentrations in winter.

scholarly journals The vascular flora of the Lake Thoreau Environmental Center, Forrest and Lamar counties, Mississippi, with comments on compositional change after a decade of prescribed fire

2020 ◽  
Vol 14 (2) ◽  
pp. 413-433
Author(s):  
William J. McFarland, ◽  
Danielle Cotton, ◽  
Mac H. Alford ◽  
Micheal A. Davis
Keyword(s):  
Species Diversity ◽  
Prescribed Fire ◽  
Longleaf Pine ◽  
Vascular Plant ◽  
Pinus Palustris ◽  
Woody Species ◽  
University Of Southern Mississippi ◽  
The North ◽  
Rich Diversity ◽  
North American Coastal Plain

Longleaf pine (Pinus palustris Mill.) ecosystems exhibit high species diversity and are major contributors to the extraordinary levels of regional biodiversity and endemism found in the North American Coastal Plain Province. These forests require frequent fire return intervals (every 2–3 years) to maintain this rich diversity. In 2009, a floristic inventory was conducted at the Lake Thoreau Environmental Center owned by the University of Southern Mississippi in Hattiesburg, Mississippi. The Center is located on 106 ha with approximately half covered by a 100+ year old longleaf pine forest. When the 2009 survey was conducted, fire had been excluded for over 20 years resulting in a dense understory dominated by woody species throughout most of the forest. The 2009 survey recorded 282 vascular plant species. Prescribed fire was reintroduced in 2009 and reapplied again in 2010, 2012, 2014, 2016, and 2018. A new survey was conducted in 2019 to assess the effects of prescribed fire on floristic diversity. The new survey found an additional 268 species bringing the total number of plants species to 550. This study highlights the changes in species diversity that occurs when fire is reintroduced into a previously fire-suppressed system and the need to monitor sensitive areas for changes in species composition.

scholarly journals DIVERSIFICATION OF GAS SUPPLIES AS A CORNERSTONE OF GAS SECURITY IN THE FRAMEWORK OF THE THREE SEAS INITIATIVE

2021 ◽  
Vol 2 (2) ◽  
pp. 1-8
Author(s):  
Danylo Stonis
Keyword(s):  
Natural Gas ◽  
Eastern Europe ◽  
Central Europe ◽  
Security Policy ◽  
Energy Transport ◽  
Transportation Infrastructure ◽  
The European Union ◽  
The North ◽  
Gas Market ◽  
South Axis

The article overviews approaches to the diversification of gas supplies in the framework of the Three Seas Initiative. The modern geopolitical situation in Eastern and Central Europe is characterized by transformation processes in the energy sector. Due to the implementation of decarbonization policy in the European Union and subsequent shift from coal as a main energy source, a need in alternative fuel sources, such as natural gas, emerges. Therefore, a significant increase in natural gas consumption is expected, which raises a number of issues, such as dependence on a single gas supplier and orientation of the EU’s gas transmission system in East-West direction only. This issue is crucial for Eastern and Central European states, due to the underdeveloped gas infrastructure in the region and heavy dependence on a single gas supplier, such as Russia or Turkey. Hence, the Three Seas Initiative is considered as a powerful tool, designed to develop energy, transport and digital infrastructure of the region in the North-South direction, where one of the most potentially promising projects within the framework of the Three Seas Initiative is represented by the development of gas infrastructure, aimed at solving the diversification of supplies in the gas market in Eastern and Central Europe. The implementation of developed gas infrastructure and diversification of gas supplies consists of several regional projects that are relevant for those countries in the region in which they are implemented in particular and for all member states of the Three Seas Initiative in general. The main purpose of the implementation of these projects is the creation of a unified natural gas transportation infrastructure in Eastern Europe along the North-South axis. The result of such a grand reorganization in the field of gas supplies to Europe will be an increase in the number of independent suppliers in the European gas market and a decrease in the dependence of the EU countries on gas supplies from Russia. In the article, the author traced in detail the tendency of the formation of energy infrastructure along the North-South axis with focus on the projects that are being implemented by each of the participating countries within the framework of the Three Seas Initiative. This approach allows to assess the scale and integrity of the gas transportation infrastructure, that is being created in the Eastern Europe region and its contribution to the common European energy security policy.

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