Ecological effects of a major oil spill on panamanian coastal marine communities

In 1986 more than 8 million liters of crude oil spilled into a complex region of mangroves, seagrasses, and coral reefs just east of the Caribbean entrance to the Panama Canal. This was the largest recorded spill into coastal habitats in the tropical Americas. Many population of plants and animals in both oiled and unoiled sites had been studied previously, thereby providing an unprecedented measure of ecological variation before the spill. Documenation of the spread of oil and its biological begun immediately. Intertidal mangroves, algae, and associated invertebrates were covered by oil and died soon after. More surprisingly, there was also extensive mortality of shallow subtidal reef corals and infauna of seagrass beds. After 1.5 years only some organisms in areas exposed to the open sea have recovered.     

Water solubility in aluminous orthopyroxene and the origin of Earth's asthenosphere

Plate tectonics is based on the concept of rigid lithosphere plates sliding on a mechanically weak asthenosphere. Many models assume that the weakness of the asthenosphere is related to the presence of small amounts of hydrous melts. However, the mechanism that may cause melting in the asthenosphere is not well understood. We show that the asthenosphere coincides with a zone where the water solubility in mantle minerals has a pronounced minimum. The minimum is due to a sharp decrease of water solubility in aluminous orthopyroxene with depth, whereas the water solubility in olivine continuously increases with pressure. Melting in the asthenosphere may therefore be related not to volatile enrichment but to a minimum in water solubility, which causes excess water to form a hydrous silicate melt.     

Energy and the u.s. Economy: a biophysical perspective

A series of hypotheses is presented about the relation of national energy use to national economic activity (both time series and cross-sectional) which offer a different perspective from standard economics for the assessment of historical and current economic events. The analysis incorporates nearly 100 years of time series data and 3 years of cross-sectional data on 87 sectors of the United States economy. Gross national product, labor productivity, and price levels are all correlated closely with various aspects of energy use, and these correlations are improved when corrections are made for energy quality. A large portion of the apparent increase in U.S. energy efficiency has been due to our ability to expand the relative use of high-quality fuels such as petroleum and electricity, and also to relative shifts in fuel use between sectors of the economy. The concept of energy return on investment is introduced as a major driving force in our economy, and data are provided which show a marked decline in energy return on investment for all our principal fuels in recent decades. Future economic growth will depend largely on the net energy yield of alternative fuel sources, and some standard economic models may need to be modified to account for the biophysical constraints on human economic activity.     

Picosecond kinetics of events leading to reaction center bacteriochlorophyll oxidation

A transient absorption spectrum has been measured in Rhodopseudomonas spheroides R26 reaction centers. Its salient features indicate that both the bacteriopheophytin and bacteriochlorophyll chromophores play a role in the excited state. Decay of this state yields a rise time for oxidation of the reaction center complex of about 150 picoseconds.     

Health, growing performance and meat quality of pigs in indoor and outdoor housing--a controlled field trial

The purpose of the study was to compare indoor and outdoor housing of pigs and their influence on animal health, growing performance and meat quality in a controlled field trial: 29 litters (252 piglets) from indoor and 22 litters (221 piglets) from outdoor were separated at weaning. One half of each litter changed to the opposite housing resulting finally in 4 types of housing: Continuous outdoor or indoor raising and combined outdoor-indoor or indoor-outdoor raising. Pigs in continuous resp. predominant outdoor housing showed lower morbidity and mortality during all raising periods, more active behaviour, higher daily weight gain in weaned pigs and in fattening pigs, but higher feed consumption as compared to indoor housed pigs. However, feed conversion did not differ significantly. Due to climatic influences differences in morbidity were partly more significant in summer litters (intestinal infections) or in winter litters (lung infections). Outdoor pigs raised in summer resulted less often in meat classification E (lean meat percentage > 55%), however, meat quality, estimated by pH-measures did not differ significantly. We conclude from our findings that outdoor housing of pigs from birth to slaughtering may be a serious alternative to predominant indoor keeping with regard to general welfare and growing performance.