Читать книгу Coastal Ecosystems in Transition - Группа авторов - Страница 21

Sessile macrobenthic animals exhibit varying degrees of stress, including death, in response to oxygen depletion. Their exact response depends on the duration and severity of the oxygen depletion and the pattern of exposure. Although seasonal bottom‐water oxygen depletion occurs in both systems, the spatial pattern and temporal extent differs. In CB, hypoxia occurs throughout the mesohaline reach for several weeks each summer, while bottom‐water hypoxia in the NAS occurs in different locations each year and for shorter periods than in CB. Thus, macrobenthic species that grow in those reaches of CB that experience seasonal hypoxia are r‐selected (species with high growth rates that exploit less‐crowded niches, and produce many offspring) enabling rapid recovery between events. Such recovery does not occur in areas of the NAS originally dominated by slow growing, long‐lived epibenthic species. In these locations small‐scale community extirpations begin to merge, thereby exerting a cumulative effect by reducing benthic biomass and species diversity over increasingly large areas.