Search

Salt marshes are recognized as blue carbon ecosystems for their ability to rapidly sequester organic carbon (OC) via sedimentation. For this reason, there is growing interest in managing these systems to help mitigate climate change. However, in order for sediment accretion to offset ongoing CO2 emissions, organic matter undergoing burial must be derived from contemporary primary production. To investigate the provenance of OC sequestered by salt marshes, we analyzed the concentration and isotope composition (δ13C and Δ14C) of sedimentary OC in two minerogenic marshes in San Francisco Bay, California, USA. Data from the low marsh dominated by Spartinaspp. show that autochthonous OC is entering the sediment matrix and may in part be stabilized through incorporation into the mineral‐bound pool. However, the sedimentary OC stock as a whole is dominated by material with low values of δ13C (~ −20 to −25‰) and Δ14C (~ 100 to −300‰) indicating a preponderance of allochthonous OC that was retained in other OC reservoirs for 102 to 103 years prior to deposition in the marsh. Diagenetic modeling of OC and its δ13C values further shows that autochthonous OC is lost from the sediment profile at a much faster rate than allochthonous OC. The rapid turnover of contemporary autochthonous OC ("fast carbon") relative to the apparent stability of old allochthonous OC ("slow carbon") suggest that carbon burial at these sites is largely decoupled from ongoing CO2 emissions. [ABSTRACT FROM AUTHOR]

This article focuses on the case of a generalized chondrodystrophy in newborns associated with dystrophic thoracic changes which caused respiratory distress and early death. Signs and symptoms of the disease displayed the following manifestations: (1) respiratory defects; (2) pinkish skin color and cyanosis; and (3) deformed and abnormal skeletal structure. Results of radiographic, anatomic, and pathologic studies indicates that the disorder is genotypic chondrodystrophy. The author claimed that asphyxiating thoracic dystrophy has resemblance to the Ellis van Creveld syndrome. Treatment procedures for the disease involves: (1) antibiotics; (2) facilities for adequate endotracheal suctioning; (3) postural drainage; (4) nasogastric-tube feeding; and (5) oxygen therapy.