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Full-Text Articles in Life Sciences

Warm Microhabitats Drive Both Increased Respiration And Growth Rates Of Intertidal Consumers, Luke P. Miller, Bengt J. Allen, Felicia A. King, Daisy R. Chilin, Vanessa M. Reynoso, Mark W. Denny Jan 2015

Warm Microhabitats Drive Both Increased Respiration And Growth Rates Of Intertidal Consumers, Luke P. Miller, Bengt J. Allen, Felicia A. King, Daisy R. Chilin, Vanessa M. Reynoso, Mark W. Denny

Luke P. Miller

Rocky intertidal organisms are often exposed to broadly fluctuating temperatures as the tides rise and fall. Many mobile consumers living on the shore are immobile during low tide, and can be exposed to high temperatures on calm, warm days. Rising body temperatures can raise metabolic rates, induce stress responses, and potentially affect growth and survival, but the effects may differ among species with different microhabitat preferences. We measured aerial and aquatic respiration rates of 4 species of Lottia limpets from central California, and estimated critical thermal maxima. In a variety of microhabitats in the field, we tracked body temperatures and …


A Tide Prediction And Tide Height Control System For Laboratory Mesocosms, Luke P. Miller, Jeremy D. Long Jan 2015

A Tide Prediction And Tide Height Control System For Laboratory Mesocosms, Luke P. Miller, Jeremy D. Long

Luke P. Miller

Experimental mesocosm studies of rocky shore and estuarine intertidal systems may benefit from the application of natural tide cycles to better replicate variation in immersion time, water depth, and attendant fluctuations in abiotic and edaphic conditions. Here we describe a stand-alone microcontroller tide prediction open-source software program, coupled with a mechanical tidal elevation control system, which allows continuous adjustment of aquarium water depths in synchrony with local tide cycles. We used this system to monitor the growth of Spartina foliosa marsh cordgrass and scale insect herbivores at three simulated shore elevations in laboratory mesocosms. Plant growth decreased with increasing shore …


Climate Change Enhances The Negative Effects Of Predation Risk On An Intermediate Consumer, Luke P. Miller, Catherine M. Matassa, Geoffrey C. Trussell Dec 2014

Climate Change Enhances The Negative Effects Of Predation Risk On An Intermediate Consumer, Luke P. Miller, Catherine M. Matassa, Geoffrey C. Trussell

Luke P. Miller

Predators are a major source of stress in natural systems because their prey must balance the benefits of feeding with the risk of being eaten. Although this ‘fear’ of being eaten often drives the organization and dynamics of many natural systems, we know little about how such risk effects will be altered by climate change. Here, we examined the interactive consequences of predator avoidance and projected climate warming in a three-level rocky intertidal food chain. We found that both predation risk and increased air and sea temperatures suppressed the foraging of prey in the middle trophic level, suggesting that warming …


Thermal Stress And Predation Risk Trigger Distinct Transcriptomic Responses In The Intertidal Snail Nucella Lapillus, Nathaniel D. Chu, Luke P. Miller, Stefan T. Kaluziak, Geoffrey C. Trussell, Steven V. Vollmer Nov 2014

Thermal Stress And Predation Risk Trigger Distinct Transcriptomic Responses In The Intertidal Snail Nucella Lapillus, Nathaniel D. Chu, Luke P. Miller, Stefan T. Kaluziak, Geoffrey C. Trussell, Steven V. Vollmer

Luke P. Miller

Thermal stress and predation risk have profound effects on rocky shore organisms, triggering changes in their feeding behaviour, morphology and metabolism. Studies of thermal stress have shown that underpinning such changes in several intertidal species are specific shifts in gene and protein expression (e.g. upregulation of heat-shock proteins). But relatively few studies have examined genetic responses to predation risk. Here, we use next-generation RNA sequencing (RNA-seq) to examine the transcriptomic (mRNA) response of the snail Nucella lapillus to thermal stress and predation risk. We found that like other intertidal species, N. lapillus displays a pronounced genetic response to thermal stress …


The Effect Of Water Temperature On Drilling And Ingestion Rates Of The Dogwhelk Nucella Lapillus Feeding On Mytilus Edulis Mussels In The Laboratory, Luke P. Miller Jun 2013

The Effect Of Water Temperature On Drilling And Ingestion Rates Of The Dogwhelk Nucella Lapillus Feeding On Mytilus Edulis Mussels In The Laboratory, Luke P. Miller

Luke P. Miller

In highly seasonal intertidal habitats, changes in temperature through the year may drive substantial shifts in feeding and growth rates of organisms. For the dogwhelk Nucella lapillus, attacking and consuming Mytilus edulis mussels can take hours or days, depending on temperature. Handling time of dogwhelks feeding on mussels is therefore greatly affected by ocean temperature. I recorded attack time in the laboratory, partitioned into drilling and consumption time, for juvenile dogwhelks across a range of seawater temperatures representative of field seawater temperatures during the main growing seasons of summer and autumn. The combined length of a drilling attack and subsequent …


Geographic Variation In Temperature Tolerance As An Indicator Of Potential Population Responses To Climate Change, Cascade J.B. Sorte, Sierra J. Jones, Luke P. Miller Apr 2011

Geographic Variation In Temperature Tolerance As An Indicator Of Potential Population Responses To Climate Change, Cascade J.B. Sorte, Sierra J. Jones, Luke P. Miller

Luke P. Miller

The temperature tolerances of individuals in geographically separated populations of a single species can be used as indicators of each population's potential to persist or become extinct in response to climate change. We evaluated the population-level variation in temperature tolerance in populations of several marine invertebrate taxa, including bryozoans, tunicates, bivalves, and gastropods, separated by distances of < 200 km to > 5000 km. We then combined physiological thermotolerance data with current temperature data and climate change predictions to predict which of these populations may be most vulnerable to future changes. In a trans-continental comparison of four subtidal epibenthic species, we show that populations on …


The Role Of Temperature And Desiccation Stress In Limiting The Local-Scale Distribution Of The Owl Limpet, Lottia Gigantea, Luke P. Miller, Christopher D. G. Harley, Mark W. Denny Aug 2009

The Role Of Temperature And Desiccation Stress In Limiting The Local-Scale Distribution Of The Owl Limpet, Lottia Gigantea, Luke P. Miller, Christopher D. G. Harley, Mark W. Denny

Luke P. Miller

1 Small-scale distributions of rocky intertidal organisms may be determined in part by temperature and desiccation stress during low tide and the ability of organisms to resist such stresses. Biophysical modelling techniques, coupled with data on the physiological tolerance of organisms can be used to predict the frequency and severity of abiotic stress events. 2 The limpet Lottia gigantea is a major competitor for primary space on rocky shores along the west coast of North America. The goal of this study was to quantify the thermal and desiccation tolerance of this species and to predict the frequency of stressful events …


On The Prediction Of Extreme Ecological Events, Mark W. Denny, Luke J. H. Hunt, Luke P. Miller, Christopher D. G. Harley Aug 2009

On The Prediction Of Extreme Ecological Events, Mark W. Denny, Luke J. H. Hunt, Luke P. Miller, Christopher D. G. Harley

Luke P. Miller

Ecological studies often focus on average effects of environmental factors, but ecological dynamics may depend as much upon environmental extremes. Ecology would therefore benefit from the ability to predict the frequency and severity of extreme environmental events. Some extreme events (e.g., earthquakes) are simple events: either they happen or they don't, and they are generally difficult to predict. In contrast, extreme ecological events are often compound events, resulting from the chance coincidence of run-of-the-mill factors. Here we present an environmental bootstrap method for resampling short-term environmental data (rolling the environmental dice) to calculate an ensemble of hypothetical time series that …


Life On The Edge: Morphological And Behavioral Adaptations For Survival On Wave-Swept Shores, Luke P. Miller May 2008

Life On The Edge: Morphological And Behavioral Adaptations For Survival On Wave-Swept Shores, Luke P. Miller

Luke P. Miller

Wave-swept rocky shores serve as a home to a great diversity of organisms and are some of the most biologically productive habitats on earth. This burgeoning community exists in spite of the fact that the zone between the high and low tide marks can be one of the most physically harsh environments on earth. Large forces imposed by breaking waves and wide swings in temperature require the organisms living on rocky shores to adapt to a constantly changing environment or risk extirpation by physical forces. I have explored a number of hypothesized adaptations for survival on rocky shores and discuss …


Barriers To Flow: The Effects Of Experimental Cage Structures On Water Velocities In High-Energy Subtidal And Intertidal Environments, Luke P. Miller, Brian Gaylord Jun 2007

Barriers To Flow: The Effects Of Experimental Cage Structures On Water Velocities In High-Energy Subtidal And Intertidal Environments, Luke P. Miller, Brian Gaylord

Luke P. Miller

For decades, marine ecologists have used cages as biological enclosure or exclosure devices to manipulate movement, growth, and survival of organisms. The ability to control the densities of focal organisms makes these structures a powerful tool. However, cages can often produce artifacts that influence the outcome of experiments. Although a subset of these artifacts have been examined previously, the effects of cages on water motion have not been adequately addressed from a quantitative standpoint, especially in high-flow environments. We targeted this data gap by explicitly measuring the fractional degree of velocity reduction inside a variety of experimental cage structures across …


Dislodged But Not Dead: Survivorship Of A High Intertidal Snail Following Wave Dislodgement, Luke P. Miller, Michael J. O'Donnell, Katharine J. Mach May 2007

Dislodged But Not Dead: Survivorship Of A High Intertidal Snail Following Wave Dislodgement, Luke P. Miller, Michael J. O'Donnell, Katharine J. Mach

Luke P. Miller

Waves breaking on rocky shorelines impart large forces on intertidal organisms, sometimes dislodging individuals. Dislodged individuals may be deposited in habitats that have a greater risk of predation or that prevent return to preferred regions on the shore. Thus, dislodgement is often assumed to be lethal. We experimentally dislodged Littorina keenae snails from high in the intertidal zone to test the likelihood of survival. Under a variety of wave conditions, we measured return rates to the high shore of 54–90%, so in this species, dislodgement is not equal to death. Snails showed a strong preference for returning to the approximate …


Feeding In Extreme Flows: Behavior Compensates For Mechanical Constraints In Barnacle Cirri, Luke P. Miller Jan 2007

Feeding In Extreme Flows: Behavior Compensates For Mechanical Constraints In Barnacle Cirri, Luke P. Miller

Luke P. Miller

Plastic morphological changes in response to environmental cues can allow organisms to adapt to their local environment. Barnacle feeding legs (cirri) exhibit substantial plasticity in size and shape along wave exposure gradients on rocky shores, but only up to a certain limit in maximum water velocities. Above the limit, the morphology of the cirri becomes invariant. Behavioral observations of barnacles feeding at a wave-exposed shore indicate that the fast response time for feeding motions allows barnacles to avoid potentially damaging flows associated with breaking waves, while still allowing feeding between wave impacts. The ability of barnacles to avoid individual waves …