Nutrient Subsidies to Southern California Estuaries Can Be Characterized as Pulse-Interpulse Regimes that May Be Dampened with Extreme Eutrophy

Autor: Rachel L. Kennison, Peggy Fong, Caitlin R. Fong
Rok vydání: 2020
Předmět:
Zdroj: Estuaries and Coasts. 44:867-874
ISSN: 1559-2731
1559-2723
DOI: 10.1007/s12237-020-00810-4
Popis: Humans have increased nitrogen inputs to estuaries, necessitating research on the patterns of these resource subsidies. When originating outside an estuary, nitrogen is a resource subsidy. This subsidy can be delivered with a variety of temporal patterns, ranging from presses to pulses. In other communities, press versus pulse subsidies has substantial and divergent impacts; however, this framework is not typically used in estuaries. This study documents nitrogen concentration-frequencies in 5 Southern California estuaries that demonstrate these nutrients subsidies can often be characterized as pulse-interpulse. There were extremely high pulses of nitrogen (> 500 uM NH4, > 2500 uM NO3), even compared with other eutrophic estuaries, that were likely driven by strong seasonal and rare rainfall typical of Mediterranean climates. High nutrient concentrations were occasionally decoupled from rainfall, likely due to land use. Extreme eutrophy may have the potential to dampened pulses, producing uniform, elevated concentration-frequency inputs. These data suggest managers should target rainfall events in nutrient sampling protocols as well as monitor changes in biological indicators following these events to characterize the impact of these inputs. Climate change, population size, and coastal development will likely increase nutrient subsidies to estuaries, necessitating further research on the timing, frequency, and duration of these inputs as well as their ecological consequences. In particular, our work highlights the need to integrate pulse events into work on biological indicators in estuaries.
Databáze: OpenAIRE
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