Ecological change in dynamic environments: Accounting for temporal environmental variability in studies of ocean change biology

Abstract

The environmental conditions in the ocean have long been considered relatively more stable through time compared to the conditions on land. Advances in sensing technologies, however, are increasingly revealing substantial fluctuations in abiotic factors over ecologically and evolutionarily relevant timescales in the ocean, leading to a growing recognition of the dynamism of the marine environment as well as new questions about how this dynamism may influence species' vulnerability to global environmental change. In some instances, the diurnal or seasonal variability in major environmental change drivers, such as temperature, pH and seawater carbonate chemistry, and dissolved oxygen, can exceed the changes expected with continued anthropogenic global change. While ocean global change biologists have begun to experimentally test how variability in environmental conditions mediates species' responses to changes in the mean, the extensive literature on species' adaptations to temporal variability in their environment and the implications of this variabilityfor their evolutionary responses has not been well integrated into the field. Here, we review the physiological mechanisms underlying species' responses to changes in temperature, pCO 2 /pH (and other carbonate parameters), and dissolved oxygen, and discuss what is known about behavioral, plastic, and evolutionary strategies for dealing with variable environments. In addition, we discuss how exposure to variability may influence species' responses to changes in the mean conditions and highlight key research needs for ocean global change biology. K E Y W O R D Sadaptive tracking, bioenergetic/behavioral strategies, manipulative experiments, physiological adaptations, variable environments KROEKER Et al.

Increase in ocean acidity variability and extremes under increasing atmospheric CO<sub>2</sub>

“…Using the Taylor decomposition (Eq. 1), one can for example express the seasonal variation in [H + ] as a function of the drivers' seasonal variations (Kwiatkowski and Orr, 2018). In this study, however, we analyze the timeseries variance of [H + ] and A that also includes variability on other timescales (see Sect.…”

“…In addition to the changes in the mean, recent studies suggest that the seasonal cycles in [H + ] and are also strongly modulated under elevated atmospheric CO 2 . Higher background concentrations of dissolved inor-ganic carbon and warmer temperatures produce stronger departures from mean state values for a given change in pertinent physical or chemical drivers for [H + ] and weaker departures for (Kwiatkowski and Orr, 2018;Fassbender et al, 2018). Other studies have also addressed the changes in the seasonal cycle of pCO 2 (Landschützer et al, 2018;Gallego et al, 2018;McNeil and Sasse, 2016;Rodgers et al, 2008;Hauck and Völker, 2015).…”

“…Other studies have also addressed the changes in the seasonal cycle of pCO 2 (Landschützer et al, 2018;Gallego et al, 2018;McNeil and Sasse, 2016;Rodgers et al, 2008;Hauck and Völker, 2015). Over the 21st century and under a high-greenhouse-gas-emission scenario, Earth system model simulations project that the seasonal amplitude in surface [H + ] will increase by 81 %, whereas the seasonal amplitude for aragonite saturation state ( A ) is projected to decrease by 9 % globally on average (Kwiatkowski and Orr, 2018). Recent observation-based estimates as well as theoretical arguments support these projected increases in seasonality for [H + ] and pCO 2 (Landschützer et al, 2018;Fassbender et al, 2018).…”

“…Unlike for marine heatwaves (Frölicher et al, 2018;Collins et al, 2020) and extreme sea level events (Oppenheimer et al, 2020), little is known about the characteristics and changes of extreme ocean acidity events and, if so, only on seasonal timescales (Kwiatkowski and Orr, 2018). A global view of how extreme events in ocean chemistry will unfold in time and space and a mechanistic understanding of the relevant processes is missing.…”

Twenty‐five years of GCB: Putting the biology into global change

“…The journal has not simply reported new discoveries on impacts, but developments in Earth System representations, and means of adaptation and amelioration. The journal has also explored behavioral, plastic, and evolutionary strategies of marine species for dealing with variable environments (Byrne, Foo, Ross, & Putnam, ; Kroeker et al, ; Miller, Ota, Sumaila, Cisneros‐Montemayor, & Cheung, ).…”