Primary Productivity Distributions Along the River-Dominated Shoreline of the Bay of St. Louis, MS Estuary

Potential primary production was measured for six consecutive months (July 2010 to December 201 0) at selected stations along the shoreline of the Bay of Saint Louis (BSL) estuary. Monthly surface and a series of subsurface (0.5 m) samples were taken to observe the temporal (monthly and short-term) and spatial variability in production relative to environmental variables that potentially could influence phytoplankton photosynthesis. Daily areal primary production, PP was modeled using photosynthesis-irradiance (P-E) parameters in conjunction with in situ irradiance measurements and biomass data collected during sampling. Although spatial variability was not observed, PP varied seasonally and ranged from 1.90 g C m-2 d-1 in July to 0.06 g C m-2 d-1 in December. Short-term variability also was observed. Production ranged from 0.25 to 0.84 g C m-2 d-1 over the course of a week and within-day values ranged from 0.36 to 0. 72 g C m-2 d-1 with peak production occurring at midday. Temporal variability was attributed primarily to changes in temperature (seasonal), river discharge (week-long), and incident irradiance (diurnal). Annual production for the BSL estuary was estimated at 197.3 g C m-2 d-1 and is comparable to other temperate, mesotrophic estuaries. The results from this study provide the first modeled estimates of primary production within the BSL system and will facilitate ecological research and monitoring efforts within this locally important estuary

Human preferences for sexually dimorphic faces may be evolutionarily novel

A large literature proposes that preferences for exaggerated sex typicality in human faces (masculinity/femininity) reflect a long evolutionary history of sexual and social selection. This proposal implies that dimorphism was important to judgments of attractiveness and personality in ancestral environments. It is difficult to evaluate, however, because most available data come from large-scale, industrialized, urban populations. Here, we report the results for 12 populations with very diverse levels of economic development. Surprisingly, preferences for exaggerated sex-specific traits are only found in the novel, highly developed environments. Similarly, perceptions that masculine males look aggressive increase strongly with development and, specifically, urbanization. These data challenge the hypothesis that facial dimorphism was an important ancestral signal of heritable mate value. One possibility is that highly developed environments provide novel opportunities to discern relationships between facial traits and behavior by exposing individuals to large numbers of unfamiliar faces, revealing patterns too subtle to detect with smaller samples