Levels of Production in the Pelagic Environment of the Strait of Georgia, British Columbia: A Review

1970 ◽  
Vol 27 (7) ◽  
pp. 1251-1264 ◽  
Author(s):  
T. R. Parsons ◽  
R. J. LeBrasseur ◽  
W. E. Barraclough
Keyword(s):  
Primary Productivity ◽  
Larval Fish ◽  
Standing Stock ◽  
Production Data ◽  
Surface Layers ◽  
Local Effects ◽  
Strait Of Georgia ◽  
Pelagic Environment ◽  
High Degree ◽  
Total Primary Productivity

Data have been accumulated on seasonal levels of nutrients, primary production, and zooplankton. The occurrence and abundance of larval fish in the surface layers have been reported together with an approximate estimate of the standing stock of commercially exploited fish. The results indicate that beyond local effects, the Strait of Georgia is comparable in productivity to other nearshore waters at the same latitude. The total primary productivity of the waters was found to be approximately 120 g C/m2 per year, but a high degree of areal patchiness in all production data emphasizes the necessity of basing predictions about particular subareas on knowledge specific to the subareas in question.

Review of the Biological Oceanography of the Strait of Georgia: Pelagic Environment

1983 ◽  
Vol 40 (7) ◽  
pp. 1064-1094 ◽  
Author(s):  
P. J. Harrison ◽  
J. D. Fulton ◽  
F. J. R. Taylor ◽  
T. R. Parsons
Keyword(s):  
Food Web ◽  
Primary Productivity ◽  
Larval Fish ◽  
Standing Stock ◽  
River Plume ◽  
Limiting Factors ◽  
Fraser River ◽  
Strait Of Georgia ◽  
The North ◽  
Rate Processes

Different components of the food web in the Strait of Georgia are reviewed. The phytoplankton are dominated by diatoms; however, flagellates may dominate in the winter. Chlorophyll a concentrations may range from < 1 mg∙m−3 in the winter to > 15 mg∙m−3 during blooms. The average annual primary productivity is about 280 g C∙m−2 for the strait, but it is higher in frontal areas at the north and south ends of the strait and near the Fraser River plume. Light limits primary productivity during the winter months, while nutrients (nitrogen) and grazing are the limiting factors during the late spring and summer. Turbidity and salinity effects occur near the Fraser River plume. The surface macrozooplankton community is composed chiefly of copepods. Mid- and deep-water communities consist of euphausiids, chaetognaths, and some deep-living copepods, which overwinter at depth. The standing stock of macrozooplankton (> 350 μm) to 400 m, ranges from 0.1 to 2.0 g wet wt∙m−3. Few estimates of secondary production and standing stock estimates of microzooplankton have been made. Horizontal patches of zooplankton have been encountered and may be important feeding sites for some fish. Standing stock associations of the dominant species in the food web of the strait are reasonably well known, but assessment of food web dynamics from these limited standing stock measurements is often inaccurate. There is a noticeable absence of data on how rate processes affect standing stocks, and it is particularly an understanding of these interrelationships that is needed for fisheries management. There is an urgent need for more interaction between biological oceanographers and fisheries scientists, particularly in the area of zooplankton grazing by larval fish.

Studies on a Calanus Patch II. The estimation of algal productive rates

1963 ◽  
Vol 43 (2) ◽  
pp. 339-347 ◽  
Author(s):  
D. H. Cushing
Keyword(s):  
Primary Productivity ◽  
Unit Volume ◽  
Standing Stock ◽  
Single Species ◽  
Algal Community ◽  
Division Rate ◽  
Common Experience ◽  
Unit Surface ◽  
The Common ◽  
Algal Material

Algal productive rates have rarely been estimated at sea, although many estimates have been made of primary productivity as g carbon/m2/day. A distinction may be drawn between productive rate and productivity, and it is in the use of the term ‘standing stock’. The latter is the quantity of living algal material per unit volume or beneath unit surface. The productive rate is the rate at which the standing stock reproduces itself; for a given species it is of course a division rate. It is expedient to use the term ‘division rate’ for a single species, but the term ‘productive rate’ may be used for the whole algal community. The productivity is the product of standing stock and productive rate and so contains in it the very great variations of standing stock that are the common experience of all planktologists.

Characterizing spatial structures of larval fish assemblages at multiple scales in relation to environmental heterogeneity in the Strait of Georgia (British Columbia, Canada)

2018 ◽  
Vol 75 (11) ◽  
pp. 1902-1914 ◽  
Author(s):  
Lu Guan ◽  
John F. Dower ◽  
Pierre Pepin
Keyword(s):  
British Columbia ◽  
Environmental Heterogeneity ◽  
Multiple Scales ◽  
Larval Fish ◽  
Critical Role ◽  
Multiscale Approach ◽  
Spatial Structures ◽  
Strait Of Georgia ◽  
Medium Scale

Spatial structures of larval fish in the Strait of Georgia (British Columbia, Canada) were quantified in the springs of 2009 and 2010 to investigate linkages to environmental heterogeneity at multiple scales. By applying a multiscale approach, principal coordinate neighborhood matrices, spatial variability was decomposed into three predefined scale categories: broad scale (>40 km), medium scale (20∼40 km), and fine scale (<20 km). Spatial variations in larval density of the three dominant fish taxa with different early life histories (Pacific herring (Clupea pallasii), Pacific hake (Merluccius productus), and northern smoothtongue (Leuroglossus schmidti)) were mainly structured at broad and medium scales, with scale-dependent associations with environmental descriptors varying interannually and among species. Larval distributions in the central-southern Strait were mainly associated with salinity, temperature, and vertical stability of the top 50 m of the water column on the medium scale. Our results emphasize the critical role of local estuarine circulation, especially at medium spatial scale, in structuring hierarchical spatial distributions of fish larvae in the Strait of Georgia and suggest the role of fundamental differences in life-history traits in influencing the formation and maintenance of larval spatial structures.

scholarly journals CHANGES IN THE MUCOSA OF THE UTERINE POD IN CANCER OF THE VAGINAL PART AND CERVIX

2020 ◽  
Vol 5 (5) ◽  
pp. 410-435
Author(s):  
M. Mironov
Keyword(s):  
Mucous Membrane ◽  
Individual Case ◽  
The Body ◽  
Lymphoid Cells ◽  
Surface Layers ◽  
First Case ◽  
Epitheloid Cells ◽  
Deep Layers ◽  
High Degree ◽  
Sarcomatous Degeneration

Changes in the mucous membrane of the body of the uterus, accompanying cancer of the vaginal part and cervix, drew special attention after the work of Abel (see No. I), which appeared in 1888. The author studied the mucous membrane of the body of the uterus, taken from extirpated cases of 6 uterus for carcinoma portionis and in 1 case for carcinoma cervicis. "In all cases, the mucous membrane is dull," says the author (p. 279, 1. p.), To a high degree of alteration, while the mucous membrane of the cervix is ​​relatively insignificantly diseased. " These changes, as can be seen from the description of each individual case, concern both the gland and the intermediate tissue, and the first in all cases were multiplied and represented corkscrew gyrus; some of them were enlarged or contained ectases of the lateral walls and processes protruding into the lumen of the gland. Changes in the intermediate tissue in cases 1, 2 and 4 consisted in the multiplication of cells in deep layers, and here they had a short-spindle-shaped shape, small size and went in trains in different directions; in the surface layers, they were more or less round, much larger in size and resembled epitheloid cells. In addition, a nested infiltration with small, round cells (lymphoid cells?) Met in places. In the remaining 4 cases, the changes in the intermediate tissue, according to the author's description, were the same as usually in chronic inflammation (cases 5, 6 and 7) or almost absent (case 3). On the basis of these studies, the author comes to the conclusion that changes in the mucous membrane of the body of the uterus in cancer of the vaginal part and cervix have the character of sarcomatous degeneration, which in observed 1, 2 and 4-m, already reached a rather high degree of 4, in the rest, although it did not appear as sharp as especially in the first case, but nevertheless, these changes, according to the author, cannot be considered as inflammatory, but should be taken only as a more weak degree of the same sarcomatous degeneration, by analogy with the first.

The plankton of Shelikof Strait, Alaska: standing stock, production, mesoscale variability and their relevance to larval fish survival

1996 ◽  
Vol 5 (s1) ◽  
pp. 19-38 ◽  
Author(s):  
JEFFREY. M. NAPP ◽  
LEWIS S. INCZE ◽  
PETER B. ORTNER ◽  
DEBORAH L. W. SIEFERT ◽  
LISA BRITT
Keyword(s):  
Larval Fish ◽  
Standing Stock ◽  
Mesoscale Variability ◽  
Fish Survival

Glass Hydration Mechanisms with Application to Obsidian Hydration Dating

1988 ◽  
Vol 123 ◽  
Author(s):  
William B. White
Keyword(s):  
Infrared Spectroscopy ◽  
Three Dimensional ◽  
Depth Profiling ◽  
Structural Disorder ◽  
Degree Of Polymerization ◽  
Concentration Profiles ◽  
Surface Layers ◽  
Profiling Techniques ◽  
High Degree ◽  
Depth Concentration

AbstractChemical analysis of typical obsidians place them with a group of silica- and alumina-rich glasses constructed of a three dimensional framework of silica and alumina tetrahedra with nearly all tetrahedra sharing corners. Raman and infrared spectra of unweathered obsidians confirm the high degree of polymerization as well as some additional structural disorder. Analysis of dissolution rates of various glasses shows obsidian to be among the most stable, comparable to the most durable synthetic glasses. Surface layers on glasses can be chemically characterized by depth-profiling techniques such as SIMS and SIPS that give depth-concentration profiles for individual elements. Hydration rinds on glasses can be structurally characterized by infrared spectroscopy which shows both hydration and re-polymerization as the rinds age. Because obsidians are already completely polymerized glasses, their hydration rinds are mainly a result of hydrolysis and alkali exchange.

scholarly journals High-degree gravity modes in the single sdB star HD 4539

2019 ◽  
Vol 489 (4) ◽  
pp. 4791-4801 ◽  
Author(s):  
R Silvotti ◽  
M Uzundag ◽  
A S Baran ◽  
R H Østensen ◽  
J H Telting ◽  
...  
Keyword(s):  
Large Fraction ◽  
Amplitude Spectrum ◽  
Rotation Period ◽  
Low Frequency ◽  
Surface Layers ◽  
Robust Identification ◽  
Robust Detection ◽  
Orbital Periods ◽  
High Degree

ABSTRACT HD 4539 (alias PG 0044 + 097 or EPIC 220641886) is a bright (V  = 10.2) long-period V1093 Her-type subdwarf B (sdB) pulsating star that was observed by the Kepler spacecraft in its secondary (K2) mission. We use the K2 light curve (78.7 d) to extract 169 pulsation frequencies, 124 with a robust detection. Most of these frequencies are found in the low-frequency region typical of gravity (g-)modes, but some higher frequencies corresponding to pressure (p-)modes are also detected. Therefore HD 4539 is a hybrid pulsator and both the deep and surface layers of the star can potentially be probed through asteroseismology. The lack of any frequency splitting in its amplitude spectrum suggests that HD 4539 has a rotation period longer than the K2 run and/or that it is seen pole-on. From asymptotic period spacing we see many high-degree modes, up to l  = 12, in the spectrum of HD 4539, with amplitudes as low as a few ppm. A large fraction of these modes can be identified and for ∼29 per cent of them we obtain a unique and robust identification corresponding to l ≤ 8. Our study includes also a new determination of the atmospheric parameters of the star. From low-resolution spectroscopy we obtain Teff  = 22 800 ± 160 K, log g  = 5.20 ± 0.02, and log(N(He)/N(H))  = −2.34 ± 0.05. By fitting the SED we obtain Teff  = 23 470$^{+650}_{-210}$ K, R⋆  = 0.26 ± 0.01 R⊙, and M⋆  = 0.40 ± 0.08 M⊙. Moreover, from 11 high-resolution spectra we see the radial velocity variations caused by the stellar pulsations, with amplitudes of ≈150 m s−1 for the main modes, and we can exclude the presence of a companion with a minimum mass higher than a few Jupiter masses for orbital periods below ∼300 d.

scholarly journals Surface slicks are pelagic nurseries for diverse ocean fauna

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jonathan L. Whitney ◽  
Jamison M. Gove ◽  
Margaret A. McManus ◽  
Katharine A. Smith ◽  
Joey Lecky ◽  
...  
Keyword(s):  
Larval Fish ◽  
Marine Animals ◽  
Larval Phase ◽  
Larval Fishes ◽  
Organic Debris ◽  
Pelagic Environment ◽  
Marine Larvae ◽  
Tightly Coupled ◽  
Surface Dwelling ◽  
Water Ecosystems

AbstractMost marine animals have a pelagic larval phase that develops in the coastal or open ocean. The fate of larvae has profound effects on replenishment of marine populations that are critical for human and ecosystem health. Larval ecology is expected to be tightly coupled to oceanic features, but for most taxa we know little about the interactions between larvae and the pelagic environment. Here, we provide evidence that surface slicks, a common coastal convergence feature, provide nursery habitat for diverse marine larvae, including > 100 species of commercially and ecologically important fishes. The vast majority of invertebrate and larval fish taxa sampled had mean densities 2–110 times higher in slicks than in ambient water. Combining in-situ surveys with remote sensing, we estimate that slicks contain 39% of neustonic larval fishes, 26% of surface-dwelling zooplankton (prey), and 75% of floating organic debris (shelter) in our 1000 km2 study area in Hawai‘i. Results indicate late-larval fishes actively select slick habitats to capitalize on concentrations of diverse prey and shelter. By providing these survival advantages, surface slicks enhance larval supply and replenishment of adult populations from coral reef, epipelagic, and deep-water ecosystems. Our findings suggest that slicks play a critically important role in enhancing productivity in tropical marine ecosystems.

scholarly journals Primary productivity below the seafloor at deep-sea hot springs

2018 ◽  
Vol 115 (26) ◽  
pp. 6756-6761 ◽  
Author(s):  
Jesse McNichol ◽  
Hryhoriy Stryhanyuk ◽  
Sean P. Sylva ◽  
François Thomas ◽  
Niculina Musat ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Deep Sea ◽  
Carbon Fixation ◽  
Hot Springs ◽  
Standing Stock ◽  
Deep Ocean ◽  
Rrna Gene ◽  
Geothermal Fluids ◽  
In Situ Conditions ◽  
Activity Measurements

Below the seafloor at deep-sea hot springs, mixing of geothermal fluids with seawater supports a potentially vast microbial ecosystem. Although the identity of subseafloor microorganisms is largely known, their effect on deep-ocean biogeochemical cycles cannot be predicted without quantitative measurements of their metabolic rates and growth efficiency. Here, we report on incubations of subseafloor fluids under in situ conditions that quantitatively constrain subseafloor primary productivity, biomass standing stock, and turnover time. Single-cell-based activity measurements and 16S rRNA-gene analysis showed thatCampylobacteriadominated carbon fixation and that oxygen concentration and temperature drove niche partitioning of closely related phylotypes. Our data reveal a very active subseafloor biosphere that fixes carbon at a rate of up to 321 μg C⋅L−1⋅d−1, turns over rapidly within tens of hours, rivals the productivity of chemosynthetic symbioses above the seafloor, and significantly influences deep-ocean biogeochemical cycling.

A Conceptual Approach to Improve the Continuity and Integrity of Information in Project Management

2016 ◽  
Vol 7 (3) ◽  
pp. 37-53
Author(s):  
Marcello Presulli
Keyword(s):  
Project Management ◽  
Production Data ◽  
Loose Coupling ◽  
Conceptual Approach ◽  
Host System ◽  
Software Repository ◽  
Comprehensive Benefit ◽  
High Flexibility ◽  
Suitable Framework ◽  
High Degree

This article proposes a conceptual implementation by means of a suitable framework to improve the continuity and integrity of information in project management. It is argued that this methodology offers a comprehensive benefit in terms of a holistic project management. The benefit characterizes itself mainly by a focused representation of project sections in dependence of the desired detail degree, as well as the base of information restorable any time on the basis of the origin production data. It takes advantage of a collaborative act to declare the necessities like keywords and conventions in advance, which has the main purpose to avoid semantic misinterpretation between users and the accepted model of approach. The concept of this scheme offers generally a high flexibility with only few dependencies – hence it's easy to extend the framework on consensual agreed pragmatics. Furthermore, it is shown that in practice there is a loose coupling to the underlying host system, which promotes the exchange of other systems. Since the framework payload is based on pure keyword mechanisms with expandable notation, a high degree of user-driven specialization is offered. Finally, the keyword pragmatic is explained on four keywords which have been agreed by a collaborative collection with selected industry partners and represent on behalf a possible application to a software Repository.

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