Factors Affecting Primary Production

1995 ◽  
pp. 36-83
Author(s):  
Ivan Valiela
Keyword(s):  
Primary Production ◽  
Factors Affecting

scholarly journals Factors affecting the abundance of age-0 Atlantic menhaden (Brevoortia tyrannus) in Chesapeake Bay

2016 ◽  
Vol 73 (9) ◽  
pp. 2238-2251 ◽  
Author(s):  
Edward D. Houde ◽  
Eric R. Annis ◽  
Lawrence W. Harding ◽  
Michael E. Mallonee ◽  
Michael J. Wilberg
Keyword(s):  
Environmental Factors ◽  
Primary Production ◽  
Chesapeake Bay ◽  
Primary Productivity ◽  
Atlantic Menhaden ◽  
Strongly Correlated ◽  
Brevoortia Tyrannus ◽  
Factors Affecting ◽  
Chl A ◽  
Low Levels

Abstract The abundance of prerecruit, age-0 Atlantic menhaden (Brevoortia tyrannus), declined to low levels in Chesapeake Bay in the 1990s, after two decades of high abundances in the 1970s–1980s. Environmental factors and trophodynamics were hypothesized to control age-0 menhaden abundance. Data on age-0 menhaden abundance from seine and trawl surveys were analysed with respect to primary productivity, chlorophyll a (Chl a), and environmental variables. Abundance from 1989 to 2004 was strongly correlated with metrics of primary production and euphotic-layer Chl a, especially during spring months when larval menhaden transform into filter-feeding, phytoplanktivorous juveniles. Correlation, principal components, and multiple regression analyses were conducted that identified factors associated with age-0 menhaden abundance. Primary production, Chl a, and variables associated with freshwater flow, e.g. Secchi disk depth and zooplankton assemblages, were correlated with age-0 menhaden abundance. Lengths of age-0 menhaden were positively related to mean levels of annual primary production. However, lengths were negatively related to age-0 menhaden abundance, indicating that growth may be density-dependent. The identified relationships suggest that numbers of menhaden larvae ingressing to Chesapeake Bay and environmental factors that subsequently control primary productivity and food for juveniles within the Bay may control recruitment levels of Atlantic menhaden.

scholarly journals Association Between Estuary Characteristics and Activities of the Critically Endangered Indo-Pacific Humpback Dolphin (Sousa chinensis)

2021 ◽  
Vol 8 ◽  
Author(s):  
Chi-hung Lin ◽  
Hsing-Juh Lin ◽  
Jian-Ping Suen ◽  
Lien-Siang Chou
Keyword(s):  
Primary Production ◽  
Net Primary Production ◽  
River Estuary ◽  
Late Summer ◽  
Critically Endangered ◽  
Physical Factors ◽  
Factors Affecting ◽  
Net Production ◽  
Sousa Chinensis ◽  
Autumn And Winter

The Indo-Pacific humpback dolphin (Sousa chinensis) has been reported to prefer estuary habitats. This study explored the environmental factors affecting a critically endangered population off the coast of Yunlin, Taiwan. We measured dolphin sighting rates and estuary characteristics affected by the watershed, including seven physical factors (watershed rainfall, watershed runoff, estuarine turbidity, pH, salinity, temperature, and dissolved oxygen) and two biological factors (estuarine net primary production and chlorophyll a concentration), at the Hsinhuwei River estuary in Taiwan. Dolphin activity was measured by sighting rate and behavioral indices for feeding and traveling between 2017 and 2018. We observed that when the maximum net production increased alongside rising temperatures in spring, both the dolphin sighting rate and foraging activity increased. This trend was maintained until heavy rainfall or increased river runoff occurred during late summer, which resulted in high turbidity in autumn and winter. Turbidity was significantly negatively correlated with dolphin activity (sighting rate and foraging). Furthermore, we found that dolphin traveling positively correlated with the chlorophyll a concentration and maximum net production factors, which could attract dolphins expecting more abundant prey fish in the estuary supported by the high primary production. This study provides empirical evidence on how estuary characteristics affected by the watershed can affect the sighting rate and behavioral activities of Indo-Pacific humpback dolphins.

Predicted Enhanced Coalbed Methane Recovery and CO2 Sequestration in West Henan Province

2014 ◽  
Vol 962-965 ◽  
pp. 168-171 ◽  
Author(s):  
Run Chen
Keyword(s):  
Primary Production ◽  
Coalbed Methane ◽  
Greenhouse Gas Emission ◽  
Henan Province ◽  
Coal Seams ◽  
Methane Recovery ◽  
Factors Affecting ◽  
Enhanced Coalbed Methane Recovery ◽  
Recovery Potential ◽  
Sequestration Potential

CO2injection into coal seams can not only enhance coalbed methane recovery (ECBM), but also reduce greenhouse gas emission into atmosphere. This paper describes some factors affecting CBM primary production, ECBM recovery and CO2sequestration in coal seams; and calculates CBM recovery quantity with primary production, the ECBM recovery potential quantity and CO2sequestration capacity in coal seams of West Henan Province. The results show that CBM primary and ECBM recovery potential quantity are estimated to be over 2147.278 and 1656.217 Gm3. The prediction also indicates that CO2sequestration potential quantity is about 3233.79 Gm3.

scholarly journals Nutrient Content and Limitation of the Phytoplankton Primary Production in the Estuary Area of the Vodopadnaya River (South Coast of Crimea)

2021 ◽  
Author(s):  
V. N. Egorov ◽  
◽  
N. I. Bobko ◽  
Yu. G. Marchenko ◽  
S. Ye. Sadogurskiy ◽  
...  
Keyword(s):  
Primary Production ◽  
River Runoff ◽  
Atmospheric Precipitation ◽  
Total Content ◽  
Nutrient Content ◽  
Water Area ◽  
The Black Sea ◽  
Phytoplankton Primary Production ◽  
Factors Affecting ◽  
Estuarine Area

The paper studies eutrophication of the waters of the Yalta water area caused by the Vodopadnaya River runoff and provides assessment of its influence on the characteristics of the phytoplankton primary production limitation by nutrients. The work was performed during 2020.Water samples for hydrochemical analyses were taken in fresh water of the Vodopadnaya River lower reaches and in seawater of its estuarine area. Based on the materials of observations in 2020, the paper characterizes the content of mineral nitrogen compounds (in the form of nitrites, nitrates, ammonium, and total content) and mineral phosphorus in the estuarine area of the Vodopadnaya River, which flows into the Black Sea within the city of Yalta. The influence of atmospheric precipitation on the change in the concentrations of nutrients in the waters of the mouth reach and estuarine front was determined. It was established that nutrient input with the river runoff can shift the nitrogen limitation of the phytoplankton primary production to the phosphorus one. It was shown that river runoff is one of the key factors affecting the degree of eutrophication of sea waters within the recreational zone of Yalta. This should be taken into account when developing strategies for optimizing the urban environment and recreational and tourist infrastructure of the region.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

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