Mercury speciation and transport via submarine groundwater discharge at a southern California coastal lagoon system.

We measured total mercury (Hg(T)) and monomethylmercury (MMHg) concentrations in coastal groundwater and seawater over a range of tidal conditions near Malibu Lagoon, California, and used (222)Rn-derived estimates of submarine groundwater discharge (SGD) to assess the flux of mercury species to nearshore seawater. We infer a groundwater-seawater mixing scenario based on salinity and temperature trends and suggest that increased groundwater discharge to the ocean during low tide transported mercury offshore. Unfiltered Hg(T) (U-Hg(T)) concentrations in groundwater (2.2-5.9 pM) and seawater (3.3-5.2 pM) decreased during a falling tide, with groundwater U-Hg(T) concentrations typically lower than seawater concentrations. Despite the low Hg(T) in groundwater, bioaccumulative MMHg was produced in onshore sediment as evidenced by elevated MMHg concentrations in groundwater (0.2-1 pM) relative to seawater (∼0.1 pM) throughout most of the tidal cycle. During low tide, groundwater appeared to transport MMHg to the coast, resulting in a 5-fold increase in seawater MMHg (from 0.1 to 0.5 pM). Similarly, filtered Hg(T) (F-Hg(T)) concentrations in seawater increased approximately 7-fold during low tide (from 0.5 to 3.6 pM). These elevated seawater F-Hg(T) concentrations exceeded those in filtered and unfiltered groundwater during low tide, but were similar to seawater U-Hg(T) concentrations, suggesting that enhanced SGD altered mercury partitioning and/or solubilization dynamics in coastal waters. Finally, we estimate that the SGD Hg(T) and MMHg fluxes to seawater were 0.41 and 0.15 nmol m(-2) d(-1), respectively - comparable in magnitude to atmospheric and benthic fluxes in similar environments.

Epinephrine, norepinephrine and dopamine concentrations in amphibian brain.

The whole brain concentrations of epinephrine, norepinephrine and dopamine in North American amphibians, orders Caudata and Salientia, are reported. Epinephrine is the major catecholamine in the Salientia while norepinephrine and epinephrine concentrations are roughly equivalent in suborders of Caudata. Relative regional concentrations are similar to other classes (mammals, reptiles and birds) although the absolute concentration of epinephrine is considerably higher in amphibians than in most other species.

Female homosexual behavior in Macaca mulatta.

Homosexual activity among adult females in a heterosexual group of rhesus monkeys (Macaca mulatta) is documented and discussed. The mounter was usually in the follicular stage of the menstrual cycle and the mountee was in the ovulatory period. Activity during the luteal phase was low for all animals. Female mounting did not appear to be a preparation or substitute for heterosexual activity. Ritualized solicitation patterns among the females were intense and varied, strongly resembling those for heterosexual pairs. Dominance, partner preference, sexual stimulation, reproductive state, individual characteristics, and past experience are discussed in the framework of multiple factors influencing the homosexual relationship.

Influences of season and age on maturation in vitro of rhesus monkey oocytes.

Oocytes obtained from antral follicles of adult and adolescent rhesus monkeys during the annual breeding season extruded polar bodies in vitro at significantly higher rates (50--60%) than oocytes from animals of similar age during the non-breeding season ((20--30%) or from infant and prepubertal females at any time of the year (20--30%). The proportion of oocytes degenerating in culture was greatest in groups where maturation was highest.

The duration of gestation in the squirrel monkey (Saimiri sciureus).

A restricted mating period was used to determine the duration of gestation in the squirrel monkey (Saimiri sciureus) of Colombian-Brazilian origin. Ten pregnancies were observed. The length of the gestation period was found to range from 141 to 154 days with a mean of 146.9 +/- 3.28 SD, a median of 146.5, and a modal length of 146.