Gloom and blooms: simulating phytoplankton growth moving out of a tributary into a large lake

摘要

Most studies of large lake trophic dynamics simply consider within-lake processes. For example, the classic eutrophication models modeled lower trophic level (e.g., chlorophyll a concen-tration [Chl-a]) relationships to nutrient dynamics (e.g., total phosphorus concentrations) as direct linear regressions or as linear regressions with time lags (OECD 1982). If tributaries were considered at all, they were modeled only as nutrient sources (OECD 1982) and lacked a biological load factor. Treating tributaries solely as nutrient sources is not restricted to studies performed decades ago. Even recent, well-cited studies restrict tributaries to serving as aseptic nutrient inputs to a lacustrine chemostat (see Fig. 1 in CARPENTER et al. 1998), even though tributaries contain particulate matter including phytoplankton (MALMAEUS & HAKANSON 2003). Coastal marine studies recognize the important role of tributaries as particle sources and emphasize their study to better understand offshore processes (RABALAIS et al. 1996, PAERL et al. 1998).