The incorporation of δ13C and δ18O from respired CO2 to tests and whole calcified tissues (WCT) of the sea urchin Lytechinus variegatus was investigated in 120 individuals to elucidate the influence of diet type on the calcification process. Sea urchins were raised during 4 mo in controlled seawater tanks using 3 different diets (δ13C; δ18O) (means ± SE): seagrass (−10.2 ± 0.1‰; −15.2 ± 0.3‰), ...

Filter-feeding invertebrates consume phytoplankton and detritus and therefore serve as important mediators of the exchange of materials from nearshore pelagic to intertidal benthic ecosystems. Here, we evaluated the linkages between nearshore and intertidal systems on temperate rocky reefs on the coasts of Oregon, USA, and New Zealand’s South Island. We used differences in the concentrations of...

Stable carbon and nitrogen isotopes were used to obtain estimates of the contribution of natural and supplemental feeds to the nutrition of Oreochromis niloticus in ponds (free-swimming or caged) receiving different inputs in Sagana, Kenya. Three dietary treatments were employed in the pond study: 1) the test diet; 2) a pig finisher diet; and 3) a rice bran diet. Feeding rates and fertilization...

The inter-annual stable carbon isotope ratio (δ13C) of three tree-ring cores P. euphratica (Populus Oliv.) was determined from Ejina Oasis in Northwest China. A robust and representative δ13C chronology is generated the series using an arithmetic mean method. After eliminating influence elevated atmospheric dioxide (CO2) concentration, we obtained a isotopic discrimination (Δ13C) chronology. Ac...