科研之友
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摘要
Hypoxic events are increasing in frequency and duration, especially in areas susceptible to eutrophication. Such events pose a growing threat to the health and function of marine ecosystems by altering key biological and ecological processes. Of particular concern is how hypoxia impacts upon both the reproductive biology and metabolic activity of marine organisms and what these impacts mean for biodiversity and ecosystem function. Furthermore, information on the effect of population-level processes (e.g. organism density) on individuals' biological responses to hypoxia is currently lacking, hampering predictions on population and species sensitivity to this stressor. Using a mesocosm experiment, we investigated the effects of relatively short-term hypoxia (14 d, 3.59 mg O-2 l(-1)) and organism density (5, 9, 13, 17, and 21 ind. per aquarium, equating to 500, 900, 1300, 1700, and 2100 ind. m(-2) respectively) on the aerobic metabolism and reproductive biology of a key infaunal species, the brittlestar Amphiura filiformis. While there were no observed effects of organism density, exposure to hypoxia did result in reduced metabolic rates and delayed metabolic recovery rates once normoxic (8.09 mg O-2 l(-1)) conditions were restored. Additionally, hypoxia resulted in delayed female reproductive cell development, smaller oocyte feret diameter, and a greater number of pre-vitellogenic oocytes present within the ovaries. These disruptions to metabolism and reproductive biology during hypoxia could cause major alterations in the quantity and quality of planktonic propagules supplied by benthic species to the pelagic environment, which in turn could affect benthic community diversity in the long term, as well as bentho-pelagic coupling, if repeated hypoxic events occur.
- 出版日期2015-8-27
