The reconstitution of political theory: David Easton, behavioralism, and the long road to system.

During the last half of the twentieth century, the concept of system was arguably the most important concept in the theoretical repertoire of the discipline of American political science. Although systems analysis was broadly employed in the behavioral sciences, David Easton's work was particularly influential in the study of politics. This is in part because he attempted to develop a distinct account of the political system that was not theoretically subservient either to general systems theory or to conceptions of the social system such as that advanced by Talcott Parsons. Although a great deal of attention has been devoted to Easton's theory, the origins and evolution of the system concept in his work have not been carefully reconstructed and analyzed.

Seagrass restoration enhances "blue carbon" sequestration in coastal waters.

Seagrass meadows are highly productive habitats that provide important ecosystem services in the coastal zone, including carbon and nutrient sequestration. Organic carbon in seagrass sediment, known as "blue carbon," accumulates from both in situ production and sedimentation of particulate carbon from the water column. Using a large-scale restoration (>1700 ha) in the Virginia coastal bays as a model system, we evaluated the role of seagrass, Zosteramarina, restoration in carbon storage in sediments of shallow coastal ecosystems. Sediments of replicate seagrass meadows representing different age treatments (as time since seeding: 0, 4, and 10 years), were analyzed for % carbon, % nitrogen, bulk density, organic matter content, and ²¹°Pb for dating at 1-cm increments to a depth of 10 cm. Sediment nutrient and organic content, and carbon accumulation rates were higher in 10-year seagrass meadows relative to 4-year and bare sediment. These differences were consistent with higher shoot density in the older meadow. Carbon accumulation rates determined for the 10-year restored seagrass meadows were 36.68 g C m⁻² yr⁻¹. Within 12 years of seeding, the restored seagrass meadows are expected to accumulate carbon at a rate that is comparable to measured ranges in natural seagrass meadows. This the first study to provide evidence of the potential of seagrass habitat restoration to enhance carbon sequestration in the coastal zone.