scholarly journals Reconstruction of the primary organic productivity of Campano-Maastrichtian shales of Nkporo and Aptian-Albian Awi Formations, Calabar Flank using pigment yield index

2018 ◽  
Vol 12 (3) ◽  
pp. 113-118
Author(s):  
K Ibe ◽  
◽  
C Ogwuche ◽  
Keyword(s):  
Organic Productivity

Calcification and organic productivity at the world's southernmost coral reef

2020 ◽  
Vol 227 ◽  
pp. 103870
Author(s):  
Kay L. Davis ◽  
Ashly McMahon ◽  
Rogger E. Correa ◽  
Isaac R. Santos
Keyword(s):  
Coral Reef ◽  
Organic Productivity

Climate Versus Changes in 13C Content of the Organic Component of Lake Sediments During the Late Quarternary

1975 ◽  
Vol 5 (2) ◽  
pp. 251-262 ◽  
Author(s):  
Minze Stuiver
Keyword(s):  
Lake Sediments ◽  
Climatic Changes ◽  
Organic Component ◽  
Organic Productivity

Several factors influence the long-term 13C record of the organic component in lake sediments. Two of the more predominant ones are changes in hardness of the water and changes in organic productivity. In general, during colder climatic episodes, 13C values are lower. Of 12 lakes studied, 4 have 13C records with large changes in 13C content that are to a certain degree correlative with climatic changes.

Organic productivity of an Atoll

1949 ◽  
Vol 30 (2) ◽  
pp. 245 ◽  
Author(s):  
Marston C. Sargent ◽  
Thomas S. Austin
Keyword(s):  
Organic Productivity

Impacts of land use and land cover changes upon organic productivity values in Karst ecosystems: a case study of Northwest Guangxi, China

2010 ◽  
Vol 4 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Mingyang Zhang ◽  
Kelin Wang ◽  
Hongsong Chen ◽  
Huiyu Liu ◽  
Yuemin Yue ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Changes ◽  
Karst Ecosystems ◽  
Organic Productivity

Epilogue: recommendations of the Workshop Session

1986 ◽  
Vol 88 ◽  
pp. 291-298
Author(s):  
I.N. McCave
Keyword(s):  
Continental Margin ◽  
Focus Of Attention ◽  
Regional Studies ◽  
East Side ◽  
Workshop Session ◽  
Research Papers ◽  
The West ◽  
Norwegian Sea ◽  
Downward Flux ◽  
Organic Productivity

Following the presentation of research papers, a group of invited participants examined the opportunities for further research in the Rockall Channel area. The chairman suggested that fundamental oceanographic problems which were well displayed in the area should be the focus of attention rather than regional studies for their own sake. It is indeed fortunate that a region so close to home ports should show many features whose examination would lead to general advances in oceanography. The area has an important slope current on its east side and influx of Norwegian Sea Overflow along the west. These produce differing sedimentary signatures. The downward flux of energy and rapid flux of particles are perhaps responsible for seasonality shown in reproduction of benthos. The continental margin shows significant upwelling and high organic productivity

scholarly journals Global coral reef ecosystems exhibit declining calcification and increasing primary productivity

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Kay L. Davis ◽  
Andrew P. Colefax ◽  
James P. Tucker ◽  
Brendan P. Kelaher ◽  
Isaac R. Santos
Keyword(s):  
Coral Reef ◽  
Multiple Stressors ◽  
Coral Cover ◽  
Meta Analysis ◽  
Environmental Drivers ◽  
Spatiotemporal Trends ◽  
Coral Reef Resilience ◽  
Coral Reef Ecosystems ◽  
Seawater Carbonate Chemistry ◽  
Organic Productivity

AbstractLong-term coral reef resilience to multiple stressors depends on their ability to maintain positive calcification rates. Estimates of coral ecosystem calcification and organic productivity provide insight into the environmental drivers and temporal changes in reef condition. Here, we analyse global spatiotemporal trends and drivers of coral reef calcification using a meta-analysis of ecosystem-scale case studies. A linear mixed effects regression model was used to test whether ecosystem-scale calcification is related to seasonality, methodology, calcifier cover, year, depth, wave action, latitude, duration of data collection, coral reef state, Ωar, temperature and organic productivity. Global ecosystem calcification estimated from changes in seawater carbonate chemistry was driven primarily by depth and benthic calcifier cover. Current and future declines in coral cover will significantly affect the global reef carbonate budget, even before considering the effects of sub-lethal stressors on calcification rates. Repeatedly studied reefs exhibited declining calcification of 4.3 ± 1.9% per year (x̄  = 1.8 ± 0.7 mmol m−2 d−1 yr−1), and increasing organic productivity at 3.0 ± 0.8 mmol m−2 d−1 per year since 1970. Therefore, coral reef ecosystems are experiencing a shift in their essential metabolic processes of calcification and photosynthesis, and could become net dissolving worldwide around 2054.

scholarly journals Revisiting the Cupidito unit (Cupido Formation) along peritidal carbonates from northeastern Mexico

2020 ◽  
Vol 37 (1) ◽  
pp. 9-25 ◽  
Author(s):  
Felipe de Jesús Torres de la Cruz ◽  
Elizabeth Chacón-Baca ◽  
Gabriel Chávez-Cabello ◽  
María Isabel Hernández-Ocaña
Keyword(s):  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Equilibrium Conditions ◽  
Diagnostic Features ◽  
Depositional Sequence ◽  
Short Pulses ◽  
Upper Limit ◽  
Stratigraphic Model ◽  
Northeastern Mexico ◽  
Organic Productivity

Depositional episodes are readily identified along representative localities of the Lower Cretaceous Cupido platform in northeastern Mexico. The basal part of the Cupido Formation exhibits a progradational reef platform that, at the upper limit, is truncated by a sequence boundary defined by a breccia. This breccia marks the development of a peculiar sedimentary facies informally known as the Cupidito unit, a distinctive stratigraphical unit in northeastern Mexico that remained uninterpreted for decades. Through the analysis of facies, microfacies and stable isotope comparisons from representative localities (Potrero Chico, Potrero de García, La Huasteca, La Muralla and Puerto Mexico) and from other previously reported outcrops, this work describes six diagnostic features for Cupidito and an improved stratigraphic model is proposed. The depositional sequence suggests a broad flat-topped platform with a general low organic productivity and restricted conditions followed by recurrent inundations of lagoon waters. Before drowning, this carbonate platform remained under equilibrium conditions interrupted by short pulses of relative higher-temperatures (48.3 °C and 39.2 °C). Coral-rudist-stromatoporoid patch-reefs with inferred inter-tropical temperatures between 31.5 °C and 32.2 °C originated as a progradational response to the instauration of a new Sequence Boundary at the base of Cupidito.

Precambrian atmospheric oxygen: evidence in the sedimentary distributions of carbon, sulfur, uranium, and iron

1976 ◽  
Vol 13 (9) ◽  
pp. 1161-1185 ◽  
Author(s):  
Erich Dimroth ◽  
Michael M. Kimberley
Keyword(s):  
Oxygen Pressure ◽  
Ferrous Iron ◽  
Atmospheric Oxygen ◽  
Sedimentary Rocks ◽  
Major Change ◽  
Free Atmosphere ◽  
Ambient Oxygen ◽  
Iron Formations ◽  
Organic Productivity ◽  
Sedimentary Pyrite

The sedimentary distributions of carbon, sulfur, uranium, and ferric and ferrous iron depend greatly upon ambient oxygen pressure and should reflect any major change in proportion of oxygen in the atmosphere or hydrosphere. The similar distributions of these elements in sedimentary rocks of all ages are here interpreted to indicate the existence of a Precambrian atmosphere containing much oxygen.Organic carbon contents and distributions are similar in Precambrian and Quaternary sedimentary rocks and sediments, although distributions in both would have been sensitive to variations in rates of organic productivity and atmospheric oxygen pressure. Sedimentary pyrite is almost invariably closely associated with organic carbon, suggestive of formation by sulfate reduction, in sedimentary rocks of any age. Archean and Middle Precambrian cherty iron formations and uranium ores resemble Phanerozoic ores and probably formed similarly by diagenetic concentration. In general, we find no evidence in the sedimentary distributions of carbon, sulfur, uranium, or iron, that an oxygen-free atmosphere has existed at any time during the span of geological history recorded in well preserved sedimentary rocks.

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