How will species cope with a rapidly changing environment? How does this affect biological levels of organization beyond individuals (e.g. populations and communities)?
I am interested in what the future holds for coastal marine species. My approach here is to link laboratory experiments measuring tolerance and performance to in situ environmental data. I am very excited for our research (Cheng et al. 2016; Proceedings B) examining how atmospheric rivers affected a population of wild oysters in San Francisco Bay. Atmospheric rivers (ARs) are long and narrow corridors of enhanced water vapor transport. ARs deliver extreme precipitation events that may increase in frequency, intensity, and duration under climate change scenarios. To our knowledge, we provide the first evidence for the biological consequences of ARs. In March 2011, a series of ARs delivered extreme precipitation to the San Francisco Bay watershed, which was correlated with an extreme freshwater discharge, which drove salinity to the lethal limits of oyster tolerance. This resulted in the mass mortality of wild oysters, possibly one of the most abundant populations throughout this species range!
How do multiple stressors interact to influence species? Does this interaction depend on temporal features?
Environmental stressors are perturbations that are foreign or natural but excessive. Natural systems are typically characterized by multiple stressors that occur at the same time (coincidence) or with temporal delays (latent). We examined how multiple stressors (temperature, hypoxia, and low salinity) may influence organismal physiology. Importantly, we modeled our experiments after time series data from Elkhorn Slough, California, an estuary that is heavily influenced by hypoxia.
In this experiment, we exposed newly settled Olympia oysters to warming and hypoxic stress (oxygen depleted waters). We found that warming actually offset effects of hypoxia, which reduced growth (Cheng et al. 2015; Global Change Biology). These effects were still evident 86 days later! This was a striking finding because much research had indicated that warming intensifies the effects of hypoxia by increasing metabolic rate.