Scale-dependent effects of marine subsidies on the island biogeographic patterns of plants.

Although species richness can be determined by different mechanisms at different spatial scales, the role of scale in the effects of marine inputs on island biogeography has not been studied explicitly. Here, we evaluated the potential influence of island characteristics and marine inputs (seaweed wrack biomass and marine-derived nitrogen in the soil) on plant species richness at both a local (plot) and regional (island) scale on 92 islands in British Columbia, Canada. We found that the effects of subsidies on species richness depend strongly on spatial scale.

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.

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.

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.

Natural acidification changes the timing and rate of succession, alters community structure, and increases homogeneity in marine biofouling communities.

Ocean acidification may have far-reaching consequences for marine community and ecosystem dynamics, but its full impacts remain poorly understood due to the difficulty of manipulating pCO at the ecosystem level to mimic realistic fluctuations that occur on a number of different timescales. It is especially unclear how quickly communities at various stages of development respond to intermediate-scale pCO change and, if high pCO is relieved mid-succession, whether past acidification effects persist, are reversed by alleviation of pCO stress, or are worsened by departures from prior high pCO conditions to which organisms had acclimatized. Here, we used reciprocal transplant experiments along a shallow water volcanic pCO gradient to assess the importance of the timing and duration of high pCO exposure (i.

Field-based experimental acidification alters fouling community structure and reduces diversity.

Increasing levels of CO2 in the atmosphere are affecting ocean chemistry, leading to increased acidification (i.e. decreased pH) and reductions in calcium carbonate saturation state.