Epibiont communities on mussels in relation to parasitism and location in the rocky intertidal zone.

The factors shaping host-parasite interactions and epibiont communities in the variable rocky intertidal zone are poorly understood. California mussels, Mytilus californianus, are colonized by endolithic cyanobacterial parasites that erode the host shell. These cyanobacteria become mutualistic under certain abiotic conditions because shell erosion can protect mussels from thermal stress.

The prokaryotic and eukaryotic microbiome of Pacific oyster spat is shaped by ocean warming but not acidification.

Pacific oysters ( a.k.a.

Temperature dependence of competitive ability is cold-shifted compared to that of growth rate in marine phytoplankton.

The effect of climate warming on community composition is expected to be contingent on competitive outcomes, yet approaches to projecting ecological outcomes often rely on measures of density-independent performance across temperatures. Recent theory suggests that the temperature response of competitive ability differs in shape from that of population growth rate. Here, we test this hypothesis empirically and find thermal performance curves of competitive ability in aquatic microorganisms to be systematically left-shifted and flatter compared to those of exponential growth rate.

Not just range limits: Warming rate and thermal sensitivity shape climate change vulnerability in a species range center.

Climate change manifests unevenly across space and time and produces complex patterns of stress for ecological systems. Species can also show substantial among-population variability in response to environmental change across their geographic range due to evolutionary processes. Explanatory factors or their proxies, such as temperature and latitude, help parse these sources of environmental and intraspecific variability; however, overemphasizing latitudinal trends can obscure the role of local environmental conditions in shaping population vulnerability to climate change.

Lethal and sublethal implications of low temperature exposure for three intertidal predators.

Benthic invertebrate predators play a key role in top-down trophic regulation in intertidal ecosystems. While the physiological and ecological consequences of predator exposure to high temperatures during summer low tides are increasingly well-studied, the effects of cold exposure during winter low tides remain poorly understood. To address this knowledge gap, we measured the supercooling points, survival, and feeding rates of three intertidal predator species in British Columbia, Canada - the sea stars Pisaster ochraceus and Evasterias troschelii and the dogwhelk Nucella lamellosa - in response to exposure to sub-zero air temperatures.

Ocean acidification increases susceptibility to sub-zero air temperatures in ecosystem engineers and limits poleward range shifts.

Ongoing climate change has caused rapidly increasing temperatures and an unprecedented decline in seawater pH, known as ocean acidification. Increasing temperatures are redistributing species toward higher and cooler latitudes that are most affected by ocean acidification. While the persistence of intertidal species in cold environments is related to their capacity to resist sub-zero air temperatures, studies have never considered the interacting impacts of ocean acidification and freeze stress on species survival and distribution.

The unprecedented Pacific Northwest heatwave of June 2021.

In late June 2021 a heatwave of unprecedented magnitude impacted the Pacific Northwest region of Canada and the United States. Many locations broke all-time maximum temperature records by more than 5 °C, and the Canadian national temperature record was broken by 4.6 °C, with a new record temperature of 49.

The journey of hull-fouling mobile invaders: basibionts and boldness mediate dislodgement risk during transit.

Vessel hull-fouling is responsible for most bioinvasion events in the marine environment, yet it lacks regulation in most countries. Although experts advocate a preventative approach, research efforts on pre-arrival processes are limited. The performance of mobile epifauna during vessel transport was evaluated laboratory simulations, using the well-known invasive Japanese skeleton shrimp (, and its native congener as case study.

Extreme heatwave drives topography-dependent patterns of mortality in a bed-forming intertidal barnacle, with implications for associated community structure.

Heatwave frequency and intensity will increase as climate change progresses. Intertidal sessile invertebrates, which often form thermally benign microhabitats for associated species, are vulnerable to thermal stress because they have minimal ability to behaviourally thermoregulate. Understanding what factors influence the mortality of biogenic species and how heatwaves might impact their ability to provide habitat is critical.

Predicting responses to marine heatwaves using functional traits.

Marine heatwaves (MHWs), discrete but prolonged periods of anomalously warm seawater, can fundamentally restructure marine communities and ecosystems. Although our understanding of these events has improved in recent years, key knowledge gaps hinder our ability to predict how MHWs will affect patterns of biodiversity. Here, we outline a functional trait approach that enables a better understanding of which species and communities will be most vulnerable to MHWs, and how the distribution of species and composition of communities are likely to shift through time.

Ecological and environmental context shape the differential effects of a facilitator in its native and invaded ranges.

Invasive species often exhibit disproportionately strong negative effects in their introduced range compared to their native range, and much research has been devoted to understanding the role of shared evolutionary history, or lack thereof, in driving these differences. Less studied is whether introduced species, particularly those that are important as facilitators in their native range, have persistent positive effects in their invaded range despite a lack of a shared evolutionary history with the invaded community. Here, we manipulated the density of a habitat-forming facilitator, the high intertidal acorn barnacle Balanus glandula, factorially with herbivore density in its native range (Bluestone Point, British Columbia, Canada) and invaded range (Punta Ameghino, Chubut Province, Argentina) to determine how this facilitator differentially affects associated species at these two locations.

Whole-organism responses to constant temperatures do not predict responses to variable temperatures in the ecosystem engineer .

Understanding and predicting responses of ectothermic animals to temperature are essential for decision-making and management. The thermal performance curve (TPC), which quantifies the thermal sensitivity of traits such as metabolism, growth and feeding rates in laboratory conditions, is often used to predict responses of wild populations. However, central assumptions of this approach are that TPCs are relatively static between populations and that curves measured under stable temperature conditions can predict performance under variable conditions.

Drivers of plasticity in freeze tolerance in the intertidal mussel .

Freezing is an extreme stress to living cells, and so freeze-tolerant animals often accumulate protective molecules (termed cryoprotectants) to prevent the cellular damage caused by freezing. The bay mussel, , is an ecologically important intertidal invertebrate that can survive freezing. Although much is known about the biochemical correlates of freeze tolerance in insects and vertebrates, the cryoprotectants that are used by intertidal invertebrates are not well characterized.

Multiple stressors drive convergent evolution of performance properties in marine macrophytes.

Extreme environments have driven the evolution of some of the most inspiring adaptations in nature. In the intertidal zone of wave-swept shores, organisms face physical forces comparable to hurricanes and must further endure thermal and desiccation stress during low tides, compromising their physiological and biomechanical performance. We examine how these multiple stressors have influenced the evolution of tissue properties during desiccation using eight phylogenetically independent pairs of intertidal and subtidal macrophytes.

Cascading social-ecological costs and benefits triggered by a recovering keystone predator.

Predator recovery often leads to ecosystem change that can trigger conflicts with more recently established human activities. In the eastern North Pacific, recovering sea otters are transforming coastal systems by reducing populations of benthic invertebrates and releasing kelp forests from grazing pressure. These changes threaten established shellfish fisheries and modify a variety of other ecosystem services.

Energetic context determines species and community responses to ocean acidification.

Physiological responses to ocean acidification are thought to be related to energetic trade-offs. Although a number of studies have proposed that negative responses to low pH could be minimized in situations where food resources are more readily available, evidence for such effects on individuals remain mixed, and the consequences of such effects at the community level remain untested. We explored the potential for food availability and diet quality to modify the effects of acidification on developing marine fouling communities in field-deployed mesocosms by supplementing natural food supply with one of two species of phytoplankton, differing in concentration of fatty acids.

Complex and interactive effects of ocean acidification and warming on the life span of a marine trematode parasite.

Human activities have caused an increase in atmospheric CO over the last 250 years, leading to unprecedented rates of change in seawater pH and temperature. These global scale processes are now commonly referred to as ocean acidification and warming, and have the potential to substantially alter the physiological performance of many marine organisms. It is vital that the effects of ocean acidification and warming on marine organisms are explored so that we can predict how marine communities may change in future.

Reciprocal abundance shifts of the intertidal sea stars, Evasterias troschelii and Pisaster ochraceus, following sea star wasting disease.

Disease emergence occurs within the context of ecological communities, and disease driven declines in host populations can lead to complex direct and indirect ecological effects. Varying effects of a single disease among multiple susceptible hosts could benefit relatively resistant species. Beginning in 2013, an outbreak of sea star wasting disease (SSWD) led to population declines of many sea star species along the west coast of North America.

Recruitment tolerance to increased temperature present across multiple kelp clades.

Kelp systems dominate nearshore marine environments in upwelling zones characterized by cold temperatures and high nutrients. Worldwide, kelp population persistence and recruitment success generally decreases with rising water temperatures coupled with low nutrients, making kelp populations vulnerable to impending warming of the oceans. This response to climate change at a global scale, however, may vary due to regional differences in temperature variability, acclimation, and differential responses of kelp species to changing conditions.

Caprellid amphipods ( spp.) are vulnerable to both physiological and habitat-mediated effects of ocean acidification.

Ocean acidification (OA) is one of the most significant threats to marine life, and is predicted to drive important changes in marine communities. Although OA impacts will be the sum of direct effects mediated by alterations of physiological rates and indirect effects mediated by shifts in species interactions and biogenic habitat provision, direct and indirect effects are rarely considered together for any given species. Here, we assess the potential direct and indirect effects of OA on a ubiquitous group of crustaceans: caprellid amphipods ( and ).

Author Correction: Increased food supply mitigates ocean acidification effects on calcification but exacerbates effects on growth.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Increased food supply mitigates ocean acidification effects on calcification but exacerbates effects on growth.

Because many of the negative effects of ocean acidification on marine life may result from underlying energetic short-falls associated with increased metabolic demands, several studies have hypothesized that negative responses to high CO could be reduced by energy input. Although this hypothesis was supported by a recent meta-analysis, we believe that the meta-analytic calculation used was not appropriate to test the stated hypothesis. Here, we first clarify the hypothesis put forward, the crux being that the effects of increased food supply and CO interact statistically.