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The effect of Ocean Acidification (OA) on marine biota is quasi-predictable at best. While perturbation studies, in the form of incubations under elevated pCO(2), reveal sensitivities and responses of individual species, one missing link in the OA story results from a chronic lack of pH data specific to a given species' natural habitat. Here, we present a(More)
Phosphorus (P) is an essential element to all life, being a structural and functional component of all organisms.1-4 P provides the phosphate-ester backbone of DNA and RNA, and it is crucial in the transmission of chemical energy through the ATP molecule (Figure 1). P is also a structural constituent in many cell components such as phosphoproteins, and(More)
We used the dual isotopic composition of nitrate (d15N and d18O) within the estuarine system of San Francisco (SF) Bay, California, to explore the utility of this approach for tracing sources and cycling of nitrate (NO 3 ). Surface water samples from 49 sites within the estuary were sampled during July–August 2004. Spatial variability in the isotopic(More)
Nitrogen (N2) fixation rates were determined on bulk water collected in the Gulf of Aqaba, Red Sea, during fall (stratified, oligotrophic) and spring (deep mixing, mesotrophic) seasons. N2 fixation rates were low yet consistently measurable in both seasons, and maximum rates of 1.0 6 0.1 nmol N L21 d21 and 1.9 6 0.2 nmol N L21 d21 occurred in the fall and(More)
Phosphorus (P) regeneration and transformation in the oceanic water column and in marine sediments depends on the chemical nature of the sinking particulate P pool. For the first time, we have characterized the molecular composition of this pool, in various oceanic settings and water depths, using P nuclear magnetic resonance (NMR) spectroscopy. Both(More)
Phytoplankton in high-light, low-nutrient ocean environments are challenged with maintaining high photosynthetic efficiency and simultaneously preventing photodamage that results from low levels of electron acceptors downstream of photosystem II (PSII). Here, we identify a process in open ocean picophytoplankton that preserves PSII activity by diverting(More)
Fluxes of total mercury (Hg(T)) and monomethylmercury (MMHg) associated with submarine groundwater discharge (SGD) at two sites onthe central California coast were estimated by combining measurements of Hg(T) and MMHg in groundwater with the use of short-lived, naturally occurring radium isotopes as tracers of groundwater inputs. Concentrations of Hg(T)(More)
As the surface ocean equilibrates with rising atmospheric CO2, the pH of surface seawater is decreasing with potentially negative impacts on coral calcification. A critical question is whether corals will be able to adapt or acclimate to these changes in seawater chemistry. We use high precision CT scanning of skeletal cores of Porites astreoides, an(More)
Seawater-soluble nutrient fractions of aerosols better represent the contribution of aerosol dry deposition to the nutrient load from this source to the ocean than any estimates based on aerosol nutrients leached in pure water or acidic solutions. To understand the solubility difference between seawater and pure water, 31 pairs of aerosol samples collected(More)
Multiple lines of evidence have shown that the isotopic composition and concentration of calcium in seawater have changed over the past 28 million years. A high-resolution, continuous seawater calcium isotope ratio curve from marine (pelagic) barite reveals distinct features in the evolution of the seawater calcium isotopic ratio suggesting changes in(More)