Biota Population Model - Important Milestone Reached
Following an earlier news item (see NDA supports leading-edge research at Westlakes below) in which we anounced a research project to develop a radiation dose model for biota populations, we are happy to report that this study is progressing well and nearing completion.
As we enter month 5 of this project, we have a fully developed a four-discrete age group, logistic growth model that includes removal by predation, natural death, fishing, radiation and migration of an isolated population of lobsters, defined by a carrying capacity that is dependent on the environment. An advanced radiation model is included, based on representing non-stochastic effects of chronic low LET radiation with the three umbrella endpoints: morbidity, impairment of reproducing ability and, at higher doses, mortality. This approach models the effect of radiation on cell recovery and reproductive capacity. The model is calibrated using an allometric approach for the calculation of LD50 as a function of the mass of the life stages
As part of this project we are also testing a model for plankton food web systems in a oceanic mixed layer, comprising environmental factors affecting plankton such as growth, uptake, respiration, grazing, excretion, predation and nutrient mixing. To this we have added a radiation model with the same kind of design as the one adapted in lobsters, so that we are in a position to evaluate the effect of dose on mortality, morbidity and reproduction in the food web.
The main overall benefit of the project so far is that we have been able to combine population modelling with radiobiology. The key goal of understanding the combined effect of radiation and other stressors in biota populations, and to inform and signal the direction of further research, is being fulfilled, signalling the potential for scientific publication. This project fulfills a critical step in implementing the ICRP vision for the system of radiation protection in biota, which aims at protecting populations.
We thank the NDA for ongoing support for this project, due to complete in early 2009.