Food Web Dynamics OverviewTeamLatest NewsTechnologiesData The overarching goal of the food web study is to further explain the complex structure and functioning of the deep-sea food web off Central California, with a primary focus on the roles of understudied midwater animals. Feeding interactions, and learning how these links fit into a food web, are critical for understanding deep-sea ecosystem structure and function. Data on feeding and food webs gathered by MBARI’s ROVs are preferred over the traditional approach of stomach-content analyses of net-caught specimens, because the latter can be biased by net feeding, stomach eversion, and rapid digestion of gelatinous prey. Our long-term access to the midwater habitat has yielded a series of publications that deal with the feeding patterns of individual species as well as of the midwater community as a whole.One of the principal ecological advances enabled by our ROVs was the discovery and documentation of an extensive and complex gelatinous fauna in deep water. As much as a quarter of global pelagic biomass may be incorporated into the bodies of these animals and they can seasonally dominate the second and third trophic levels of midwater communities. These animals were substantially undersampled by conventional methods but with the advent of undersea vehicles the “jelly web” is now recognized as a significant component of midwater ecosystems worldwide.Observations of feeding by individual species reveal striking differences in the ways that different predators consume the same type of prey. Both the siphonophore Nanomia bijuga and the ctenophore Thalassocalyce inconstans feed on euphausiid krill. The former uses stinging cells on its tentacles to stun and capture, while the latter gently enfolds the same prey in a soft, sticky lobe. In contrast the Humboldt squid, Dosidicus gigas, uses its highly dexterous arm tips to pluck individual krill from the water and carry them to the mouth. Solmissus incisa is a common midwater jelly, and a dominant predator in Monterey Bay. It is typically found down to 1000 meters depth. In situ observations have also revealed similarities and subtle distinctions in feeding by highly disparate species. The isopod Acanthamunnopsis milleri collects particles from the surrounding water using fine, stiff bristles distributed along its elongate arms, then draws the arms past its mouth to remove the accumulated food. We have observed the pelagic red crab Pleuroncodes planipes feeding in a similar manner. In contrast, another isopod, Munneurycope murrayi, collects clumps of aggregated marine snow such as discarded larvacean houses from the water column. The long, retractile filaments of the vampire squid, Vampyroteuthis infernalis were widely believed to be sensory structures until we observed them in situ being used to collect detritus and marine snow aggregates, which were subsequently drawn through the arms and to the mouth for ingestion.In all of these cases gut content analyses alone would not have allowed us to distinguish between these different feeding modes and food types.Searching the VARS database with a much broader scope has yielded a detailed description of the deep pelagic food web of Monterey Bay. Based on 743 independent feeding events, our published results indicate that gelatinous predators – siphonophores, medusae, and ctenophores – are key carnivores, comparable to fish and squid in their importance within the food web. This study also examines how gelatinous predators, once believed to be a trophic “dead-end,” are fully integrated into overall food web structure.A detailed investigation of the feeding of abundant squids in the genus Gonatus involved mining the VARS database for observations of feeding, as well as targeted dive time to seek out these predators. The surprising results showed that in addition to the small fishes we expected them to consume, gonatid squids also showed a high degree of cannibalism.Filter-feeding gelatinous animals like giant larvaceans, salps, and doliolids mediate sinking particle flux, in some cases transporting substantial amounts of carbon into the deep sea. Other predatory gelatinous animals like large siphonophores and medusae directly consume micronektonic animals (e.g., crustaceans, fishes, and small cephalopods), and are in turn consumed by pelagic predatory fishes like opah and tunas. In this way, dominant gelatinous animals serve as critical trophic nodes in epipelagic, mesopelagic, and bathypelagic food webs, necessitating ecological study of their overall roles. Read More In all of these cases gut content analyses alone would not have allowed us to distinguish between these different feeding modes and food types.Searching the VARS database with a much broader scope has yielded a detailed description of the deep pelagic food web of Monterey Bay. Based on 743 independent feeding events, our published results indicate that gelatinous predators – siphonophores, medusae, and ctenophores – are key carnivores, comparable to fish and squid in their importance within the food web. This study also examines how gelatinous predators, once believed to be a trophic “dead-end,” are fully integrated into overall food web structure.A detailed investigation of the feeding of abundant squids in the genus Gonatus involved mining the VARS database for observations of feeding, as well as targeted dive time to seek out these predators. The surprising results showed that in addition to the small fishes we expected them to consume, gonatid squids also showed a high degree of cannibalism.Filter-feeding gelatinous animals like giant larvaceans, salps, and doliolids mediate sinking particle flux, in some cases transporting substantial amounts of carbon into the deep sea. Other predatory gelatinous animals like large siphonophores and medusae directly consume micronektonic animals (e.g., crustaceans, fishes, and small cephalopods), and are in turn consumed by pelagic predatory fishes like opah and tunas. In this way, dominant gelatinous animals serve as critical trophic nodes in epipelagic, mesopelagic, and bathypelagic food webs, necessitating ecological study of their overall roles. Team Directory Bruce H. Robison Senior Scientist/Midwater Ecologist Principal Investigator Kim Reisenbichler Research Specialist Rob Sherlock Research Specialist Publications All Publications Sorry, no results were found. Latest News All News News Cameras reveal largest aggregation of fishes in abyssal deep sea News 11.23.20 News Running the gauntlet— Deep-sea animals face multiple dangers in their daily migration News 03.17.20 Technologies All Technologies Software Video Annotation and Reference System (VARS) Technology Video Annotation and Reference System (VARS) A software interface and database system that provides tools for describing, cataloging, retrieving, and viewing the data associated with deep-sea video archives. Data All Data Data Deep-Sea Guide The Deep-Sea Guide provides access to the MBARI’s database of millions of records of deep-sea animals, seafloor habitats, geological features, and research tools
News Running the gauntlet— Deep-sea animals face multiple dangers in their daily migration News 03.17.20
Software Video Annotation and Reference System (VARS) Technology Video Annotation and Reference System (VARS) A software interface and database system that provides tools for describing, cataloging, retrieving, and viewing the data associated with deep-sea video archives.
Data Deep-Sea Guide The Deep-Sea Guide provides access to the MBARI’s database of millions of records of deep-sea animals, seafloor habitats, geological features, and research tools