Systems Approach to the Concept of Environment

Author Institution: Department of Zoology and Institute of Ecology, University of GeorgiaA systems theory of environment formulates causal interactions between things, including organisms, and their environments in terms of four system theoretical abstract objects. Creaons receive stimuli and implicitly create input environments. Genons react to received causes and generate potential output environments as effects. A holon represents the combined input-output model of an entity consisting of a creaon and a genon. An environ is a creaon and its corresponding input environment, or a genon and its related output environment. The theory is presented in terms of three propositions that: (1) recognize two distinct environments (input and output) associated with things, (2) establish things and their environments as units (environs) to be taken together, and (3) partition systems into input and output environs associated with intrasystem creaons and genons, respectively

Species diversity in net phytoplankton of Raritan Bay

The annual diversity cycle in Raritan Bay net phytoplankton is described, using entropyrelated diversity indices. A theory of diversity change during succession is developed. Mean diversity levels in the estuary increased downbay in association with diminishing pollution, and the spatial pattern was strikingly related to general patterns of water mass circulation

Synoptic comparison of seston loads in the Rappahannock, York and James Rivers

This report summarizes data obtained during summer, 1962 on suspended solids profiles at Hog House Bar (Rappahannock, directly out from Urbanna Creek to 30 ft depth), the productivity buoy (York, 30 ft) and Wreck Shoal (James, adjacent to buoy 12 at edge of channel, 30 ft). Water samples obtained the same day from the three stations at s, 2 (ft), 61 10, 14, 18, 22, 26, B were analyzed for total, organic and inorganic seston by the gravimetric procedure described in VIMS Special Scientific Report No. 20 (1961). Temperature, chlorinity and extinction coefficient profiles were recorded, as well as Sand B dissolved oxygen

Hydrographic, nutrient, chlorophyll, seston and cell-count data from Chesapeake Bay plankton cruises of R/V Pathfinder and R/V Observer : January 1960 - January 1961

Also part of series: Virginia Fisheries Laboratory special scientific report ; no. 20

Nannoplankton records obtained from Chesapeake Bay cruises of R/V Pathfinder and R/V Observer : January 1960 - January 1961

Also part of series: Virginia Fisheries Laboratory special scientific report ; no. 21

Distribution of ammonia nitrogen in the lower York River, Virginia : Spring, 1961

Also part of series: Virginia Fisheries Laboratory special scientific report ; no. 25

Functional Integration of Ecological Networks through Pathway Proliferation

Large-scale structural patterns commonly occur in network models of complex systems including a skewed node degree distribution and small-world topology. These patterns suggest common organizational constraints and similar functional consequences. Here, we investigate a structural pattern termed pathway proliferation. Previous research enumerating pathways that link species determined that as pathway length increases, the number of pathways tends to increase without bound. We hypothesize that this pathway proliferation influences the flow of energy, matter, and information in ecosystems. In this paper, we clarify the pathway proliferation concept, introduce a measure of the node--node proliferation rate, describe factors influencing the rate, and characterize it in 17 large empirical food-webs. During this investigation, we uncovered a modular organization within these systems. Over half of the food-webs were composed of one or more subgroups that were strongly connected internally, but weakly connected to the rest of the system. Further, these modules had distinct proliferation rates. We conclude that pathway proliferation in ecological networks reveals subgroups of species that will be functionally integrated through cyclic indirect effects.Comment: 29 pages, 2 figures, 3 tables, Submitted to Journal of Theoretical Biolog