Evidence from nitrogen isotope ratios for enhanced productivity during formation of eastern Mediterranean sapropels

Nature ◽  
1992 ◽  
Vol 359 (6392) ◽  
pp. 223-225 ◽  
Author(s):  
S. E. Calvert ◽  
B. Nielsen ◽  
M. R. Fontugne
Keyword(s):  
Eastern Mediterranean ◽  
Nitrogen Isotope ◽  
Isotope Ratios

scholarly journals Ecological aspects of carbon and nitrogen isotope ratios of cyanobacteria

2012 ◽  
Vol 7 (3) ◽  
pp. 135-145 ◽  
Author(s):  
Eitaro Wada ◽  
Kaori Ohki ◽  
Shinya Yoshikawa ◽  
Patrick L. Parker ◽  
Chase Van Baalen ◽  
...  
Keyword(s):  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Carbon And Nitrogen ◽  
Ecological Aspects

scholarly journals Diagenetic control of nitrogen isotope ratios in Holocene sapropels and recent sediments from the Eastern Mediterranean Sea

2010 ◽  
Vol 7 (1) ◽  
pp. 1131-1165 ◽  
Author(s):  
J. Möbius ◽  
N. Lahajnar ◽  
K.-C. Emeis
Keyword(s):  
Organic Matter ◽  
Primary Production ◽  
Surface Sediments ◽  
Eastern Mediterranean ◽  
Nitrogen Isotope ◽  
Organic C ◽  
Deep Waters ◽  
Spatially Distributed ◽  
Temporal And Spatial ◽  
Recent Sediments

Abstract. The enhanced accumulation of organic matter in Eastern Mediterranean sapropels and their unusually depleted δ15N values have been attributed to either enhanced nutrient availability which led to elevated primary production and carbon sequestration or to enhanced organic matter preservation under anoxic conditions. In order to evaluate these two hypothesis we have determined Ba/Al ratios, amino acid composition, N and organic C concentrations and δ15N on sinking particles, surface sediments, eight spatially distributed core records of the youngest sapropel S1 (10-6 ka) and older sapropels (S5, S6) from two locations. These data suggest that (i) temporal and spatial variations in δ15N of sedimentary N are driven by different degrees of diagenesis at different sites rather than by changes in N-sources or primary productivity and (ii) that present day TOC export production would suffice to create a sapropel like S1 under conditions of deep-water anoxia. This implies that both enhanced TOC accumulation and δ15N depletion in sapropels were due to the absence of oxygen in deep waters. Thus preservation plays a major role for the accumulation of organic-rich sediments casting doubt the need of enhanced primary production for sapropel formation.

scholarly journals Changing patterns of habitat use by southern right whales (Eubalaena australis) on their nursery ground at Península Valdés, Argentina, and in their long-range movements

2020 ◽  
pp. 133-143
Author(s):  
Victoria J. Rowntree ◽  
Roger S. Payne ◽  
Donald M. Schell
Keyword(s):  
Habitat Use ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Small Scale ◽  
Nursery Ground ◽  
Adult Males ◽  
Human Disturbances ◽  
Eubalaena Australis ◽  
Right Whales ◽  
Southern Right Whales

Southern right whales (Eubalaena australis) have been studied on their nursery ground at Península Valdés, Argentina, every year since 1970. Since 1990, 1,208 individuals have been identified from photographs taken during annual aerial surveys; 618 whales were seen in two or more years. Patterns of habitat use have changed during the study in ways which suggest that right whales may be capable of substantial behavioral and ecological flexibility. One male and three females from Península Valdés have been sighted on other nursery grounds (Tristan da Cunha and southern Brazil). Three individuals from Península Valdés were sighted on feeding grounds off Shag Rocks and South Georgia. Some right whales from Península Valdés showed carbon and nitrogen isotope ratios very similar to those seen in right whales off South Africa, while others showed distinctive isotope ratios indicating that they fed in a different area. Whales of all ages and both sexes moved frequently between three major regions of concentration on the Península Valdés nursery ground. Subadults and adult females with calves were resighted at higher rates than adult males and females in non-calf years. Changes in the geographic distribution of whales at the Península include: (1) abandonment of a major region of concentration; (2) establishment of a nursery area adjacent to thecentre of a growing whalewatching industry; and (3) small-scale shifts in distribution, possibly in response to natural and human disturbances.

scholarly journals Nitrogen isotope ratios of nitrate and N* anomalies in the subtropical South Pacific

2015 ◽  
Vol 16 (5) ◽  
pp. 1439-1448 ◽  
Author(s):  
Chisato Yoshikawa ◽  
Akiko Makabe ◽  
Takuhei Shiozaki ◽  
Sakae Toyoda ◽  
Osamu Yoshida ◽  
...  
Keyword(s):  
South Pacific ◽  
Nitrogen Isotope ◽  
Isotope Ratios

Interstellar Nitrogen Isotope Ratios

1985 ◽  
pp. 585-586
Author(s):  
R. Güsten ◽  
H. Ungerechts
Keyword(s):  
Nitrogen Isotope ◽  
Isotope Ratios

scholarly journals Hair cortisol and stable carbon and nitrogen isotope ratios in barbary macaques ( Macaca sylvanus ) from Gibraltar

2019 ◽  
Vol 33 (9) ◽  
pp. 831-838 ◽  
Author(s):  
Michael A. Schillaci ◽  
Jessica Lintlop ◽  
Monika Sumra ◽  
Mark Pizarro ◽  
Lisa Jones‐Engel
Keyword(s):  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Hair Cortisol ◽  
Stable Carbon ◽  
Macaca Sylvanus ◽  
Barbary Macaques ◽  
Carbon And Nitrogen

scholarly journals Diet and disease in Tomar, Portugal: Comparing stable carbon and nitrogen isotope ratios between skeletons with and without signs of infectious disease

2019 ◽  
Vol 105 ◽  
pp. 59-69 ◽  
Author(s):  
Ana Curto ◽  
Patrick Mahoney ◽  
Anne-France Maurer ◽  
Cristina Barrocas-Dias ◽  
Teresa Fernandes ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Stable Carbon ◽  
Carbon And Nitrogen
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