Can strong consumer and producer effects be reconciled to better forecast ‘catastrophic’ phase-shifts in marine ecosystems?

The other ocean acidification problem: CO 2 as a resource among competitors for ecosystem dominance

“…To date, most research on ocean acidification has focused on the direct environmental impacts on individual rstb.royalsocietypublishing.org Phil Trans R Soc B 368: 20120442 species of iconic status (e.g. corals), but the capacity for indirect effects to drive change may rival the known direct effects [40].…”

Positive feedback between large-scale disturbance and density-dependent grazing decreases resilience of a kelp bed ecosystem

“…Ecosystem shifts in marine systems, such as shifts from kelp-to turf-dominated assemblages, appear to result from drivers that change the balance between production and consumption of key primary producers, which in turn alters their abundance (Burkepile & Hay 2006, Connell et al 2011, Harley et al 2012. The replacement of S. latissima and other perennial macroalgae by filamentous turf-forming algae along the west and Skagerrak coasts of Norway and Sweden appears to be a consequence of ocean warming and eutrophication that favour both turfforming algae and epiphytic algae that decrease survival of kelp (Eriksson et al 2002, Andersen et al 2011, Moy & Christie 2012.…”

“…In South Australia, pervasive turfs that replace Ecklonia radiata kelp forests are facilitated by nutrient enrichment (Gorman et al 2009), which may be exacerbated by synergism with future ocean warming and acidification , Connell & Russell 2010. Although this system generally lacks strong herbivory (Connell et al 2011), molluscan grazers have some capacity to mediate turf expansion (Russell & Connell 2005, Falkenberg et al 2014. Eutrophication also has caused the proliferation of ephemeral and filamentous algae in shallow subtidal habitats of the Baltic Sea, which is exacerbated by cascading effects of overfishing that decrease the abundance of invertebrate grazers (Eriksson et al 2009).…”

“…Our study highlights a special case where conditions that increase top-down control facilitate turf-forming algae because the dominant herbivore is a grazer of the canopy-forming species. These examples indicate that an understanding of the context-dependence of top-down and bottom-up forces, and the conditions that disrupt their relative strengths, is required to predict shifts from canopy-to turf-dominated assemblages on rocky reefs (Burkepile & Hay 2006, Connell et al 2011.…”

Ocean acidification and rising temperatures may increase biofilm primary productivity but decrease grazer consumption

“…Evidence for the impacts of changes to single environmental conditions on individual species is rapidly growing [14,34], whereas data on the synergistic impacts of multiple stressors and how species interactions may moderate these effects across trophic levels are still lacking ( [35,36], but see also [37]). It is acknowledged that these knowledge gaps are limiting the use of current ecosystem models that are otherwise well developed with respect to coastal biogeochemistry.…”