Arctic lagoon and nearshore food webs: Relative contributions of terrestrial organic matter, phytoplankton, and phytobenthos vary with consumer foraging dynamics

• DOI: 10.1016/j.ecss.2021.107388
• Publication Date: 2021-05-08T05:03:02Z
• Authors: Kelton W. McMahon; William G. Ambrose; Melinda J. Reynolds; Beverly J. Johnson; Alex Whiting; Lisa M. Clough
• Keywords: Primary producers; Phytodetritus; Trophic cascade

Characterizing energy flow and trophic linkages is fundamental to understanding the functioning resilience of Arctic ecosystems under increasing pressure from climate change anthropogenic exploitation. We used carbon nitrogen stable isotopes examine dynamics relative contribution terrestrial organic matter, water column phytoplankton, phytobenthos (benthic micro- macro-autotrophs as well sea ice algae) food webs supporting 45 macroconsumers in three coastal lagoon (Krusenstern, Sisualik, Akulaaq) adjacent Kotzebue Sound with varying degrees connectivity Cape Krusenstern National Monument, Alaska. A two-source (water particulate matter benthic sediment matter), two-isotope model informed by a Bayesian isotope mixing revealed that Lagoon-Kotzebue ecosystem supported consumers along position continuum primary consumers, including amphipods, copepods, clams level five predators, such seastars, piscivorous fishes, seals, seabirds. The producer end members, (41 ± 21%), phytoplankton (25 (34 23%) varied function of: 1) consumer foraging ecology 2) location. Suspension feeders received most their based on (49 11%) (23 5%), whereas herbivores detritivores majority phytobenthos-based webs, 58 10% 60 8%, respectively. Omnivores predators showed more even distributions resource reliance greater overall variance among species. Within invertebrates, importance decreased increased position. proximity major rivers inputs isolation Sound. Several taxa cultural subsistence local communities significant (30–90% baseline carbon) chains linked fresh matter. Our study indicates terrestrial-marine are important artisanal fisheries. These likely strengthen future regional changes erosion runoff associated disturbance.