2 research outputs found
Urchin Searchinâ: Red urchins and drift kelp found at 284 m in the mesophotic zone
Red sea urchins (Mesocentrotus franciscanus) are kelp-associated ecosystem engineers found in rocky habitats throughout the North Pacific from Baja California, Mexico, to Japan. Red sea urchins depend on kelp detritus, herein âdriftâ, for nutrition; in open coast locations (e.g., California) sea urchin abundance declines precipitously with depth outside the kelp forest owing to a lack of drift and habitat. In the Salish Sea, a region of the Northeast Pacific characterized by steep, glacier-carved rocky reefs, red sea urchins have been reported to 125 m depth. Considering the natural history of this species, we predicted red sea urchins could be found deeper than 125 m in areas with hard substrate and abundant drift. We paired submersible and scuba transects to search for deep red sea urchins and quantified availability of drift to sea urchins from the mesophotic (290 m) to macrophyte zones (90% of rocky shorelines in the Northeast Pacific from Baja California to Alaska, suggesting a major portion of the red sea urchinâs habitat, and natural history, remains to be explored
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Climate drives the geography of marine consumption by changing predator communities
The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, where biotic interactions reportedly weaken away from the equator, but it parallels an emerging pattern of a subtropical peak in marine biodiversity. The higher consumption at midlatitudes was closely related to the type of consumers present, which explained rates of consumption better than consumer density, biomass, species diversity, or habitat. Indeed, the apparent effect of temperature on consumption was mostly driven by temperature-associated turnover in consumer community composition. Our findings reinforce the key influence of climate warming on altered species composition and highlight its implications for the functioning of Earth's ecosystems