The apparent dissociation constants of carbonic acid were
determined as functions of temperature and salinity in seawater
at atmospheric pressure.
There is fair agreement between my values of K'₁ and those
of Buch et al. (1932), Lyman (1956), and Hansson (1971). My values,
on the average, are 6.7% lower than...
Desert plant communities are among the most sensitive to changes in soil water conditions. In areas with shallow aquifers, it is important to understand both the effects of groundwater alterations on vegetation and how changes in surface-soil water affect plant water uptake. Studies in arid environments have evaluated the effect...
Biological di-nitrogen (N₂) fixation is a key process in open-ocean ecosystems, where the new nitrogen (N) provided by marine diazotrophs can support a large fraction of primary productivity and carbon (C) drawdown. Recent laboratory studies have shown that elevated pCO₂ enhances the rate of N₂ fixation by select laboratory isolates...
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RicardoM. Letelier
Biological di-nitrogen (N2) fixation is a key process in open-ocean
Fluctuations in one system affect adjacent systems; mechanistic understanding of linkages helps conservation efforts be more effective by focusing on influential species and areas that facilitate connections between ecosystems. This study explored marine-derived nutrient inputs to adjacent terrestrial communities. We quantified wrack (seaweed and other organic matter) deposition at sites...
This thesis covers a wide area of the North Pacific Ocean, latitudinally from 10° to 55°N and longitudinally from Japan to the U.S. coast. With two longitudinal cruises as the main data sources and selected literature data sets as supplementary data source, the distribution of physical and chemical properties in...
The biological transformation of dinitrogen gas (N2) into combined forms(termed N2 fixation) by certain genera of oceanic cyanobacteria represents the largest incoming flux of nitrogen to the global ocean. As such, biological nitrogen fixation
plays a significant role in the regulation of oceanic productivity and the export of
carbon and...
Our view of phytoplankton has historically revolved around their inability to
control their location in space. The term phytoplankton itself underscores this
particular difference between phytoplankton and their sessile terrestrial counterparts.
Yet there are other differences between land plants and the phytoplankton that are
perhaps equally important, beyond this sessile-planktonic...
The North Pacific subtropical gyre (NPSG), once considered to be a biological desert due to low primary production (PP) and its associated variability, has been found more productive and variable than previously thought. The environmental conditions controlling this relatively high PP variability are yet to be elucidated, despite important implications...
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Mark R. Abbott, RicardoM. Letelier
The North Pacific subtropical gyre (NPSG), once
A graphical method, based on a set of acid-base titrations, is
presented for the determination of the carbon dioxide speciation in
natural solutions. The application of this method, in conjunction
with measurements of the partial pressure of carbon dioxide with
which our solutions were in equilibrium permitted the calculation
of...
The stoichiometric model of organic decomposition in seawater
(Redfield, Ketchum, and Richards, 1963) was used to describe the
oceanic distribution of total carbon dioxide. It was assumed that the
concentration of total carbon dioxide was the sum of three terms:
(1) the initial concentration of carbon dioxide, (2) the increase...
Under conditions of fixed N-limitation, as with most oligotrophic systems, the process of biological N₂ fixation (diazotrophy) is favored, provided the necessary trace elements and vitamins are sufficient. Despite the well understood contributions of N₂
fixation in oligotrophic regions, the nutritional and ecological controls of marine diazotrophs have not been...