THE ROLE OF THE OCEANS in Earth systems ecology, and the effects of climate variability on the ocean and its ecosystems, can be understood only by observing, describing, and ultimately predicting the state of the ocean as a physically forced ecological and biogeochemical system. This is a daunting but exciting...
Many trace elements (e.g., Zn, Cd, Mo) are essential phytoplankton micronutrients, making them crucial to the marine ecosystem and ultimately the carbon cycle. Because of this association trace metals are also utilized in paleoceanographic studies (e.g., Mo, Cd). However, not much is known about what controls the cycling of these...
The development of the energy crisis has caused the
use of depletable energy resources to be monitored quite
closely in the United States. Within the agricultural
sector, irrigation is a large user of energy, with the
potential of using many times more energy than all other
agricultural field operations. A...
The Critical Depth Hypothesis formalized by Sverdrup in 1953 posits that
vernal phytoplankton blooms occur when surface mixing shoals to a depth shallower than a
critical depth horizon defining the point where phytoplankton growth exceeds losses. This
hypothesis has since served as a cornerstone in plankton ecology and reflects the...
An Ls-isocitrate:NADP oxidoreductase has been isolated and
purified from embryonic chicken liver. The enzyme was purified
200 fold by means of ammonium sulfate fractionation, gel filtration
chromatography on Sephadex G-200, ion-exchange chromatography
on Bio-Gel CM-100 and adsorption chromatography on hydroxylapatite
gel.
The purified enzyme was nearly homogeneous as determined
from...
Levels of activity of glucose-6-phosphate- , 6-phosphogluconate- , and isocitric- dehydrogenase were measured in the
soluble and particulate fractions of heart, brain and liver at
several ages throughout the development of the chick embryo.
Compared to isocitric dehydrogenase, levels of glucosesphosphate-
, and 6-phosphogluconate- dehydrogenase are generally
low. This suggests...