Discoveries of deep-sea biomass and biodiversity using an ROV
MBARI researchers have discovered more animals, more particles and more activity than were previously thought to exist in the deep realm. Frequent forays with remotely operated vehicles to the deep Monterey Canyon have enabled MBARI researchers to discover new animal species on a regular basis, and to piece together their significance in the ecology of the deep. Over the institute’s first 20 years, our biologists have made major contributions to research methods and the understanding of the quantity and diversity of life in the ocean.
The best way to study animals is to observe them in their natural habitat, but that can be particularly challenging for animals that live in the oceanic water column, the 4,000-meter (2.5- mile) deep layer of water that covers most of the Earth’s surface. For more than a century the only way to examine these animals was to haul them up to the surface in nets, however nets collect and tell only part of the story. Those traditional sampling methods gave a biased view because nets shredded the soft-bodied jellies and selectively captured fishes, crustaceans, and other hard-bodied life forms.
MBARI’s Bruce Robison, a midwater ecologist, pioneered the use of both human-occupied and robotic undersea vehicles to study the deep midwater habitat directly. Working with MBARI’s marine operations staff, he developed many of the methods for midwater research using remotely operated vehicles (ROVs). The results have changed our understanding of oceanic ecosystems.
One of the most important discoveries has been the realization that gelatinous animals are important as grazers and predators that comprise a large percentage of the open ocean animal biomass. Robison estimates that gelatinous animals make up about 40 percent of the biomass in the deep sea water column. In Monterey Bay, one third of the abundant krill populations is consumed by gelatinous predators, which compete successfully against migratory krill consumers such as baleen whales, albacore tuna, and squids.
Robison, Steve Haddock, George Matsumoto, and their colleagues and students have initiated studies of the behavior of midwater animals, which would have been impossible to achieve with dead specimens from net collections. While many scientists had speculated about the value of bioluminescence (light produced by living organisms), Robison was the first to directly observe bioluminescent behavior in its natural setting and then describe how the animals use the light they produce. The midwater research team has made significant discoveries concerning oceanic carbon flux, invasive species, conservation of biodiversity, reproductive behavior, bioluminescence, chemical ecology and deep-sea community structure.
While exploring the deep water column, MBARI scientists have discovered many life forms new to science; not just new species but whole new families of species that represent evolutionary paths that are successful in the deep but are never seen in shallower waters. "Every time we dive below 2,000 meters, we see species that are new to science," explained Steve Haddock. "People talk about the importance of biodiversity, but you don't have to go to some exotic rainforest to find new species. In fact, you don't even have to go very far from shore." After thinking a minute, he added, "It's amazing to me how little we know about the animals in our own back yard. Many of these animals are actually quite abundant, but very few experts get to see them."
Future research on deep sea animals will help us understand not only who lives there, but also how they function together ecologically.
MBARI contributors to discoveries of biodiversity in the deep sea: Steve Haddock, Magdalena Halt, Russ Hopcroft, George Matsumoto, Karen Osborn, Kevin Raskoff, Kim Reisenbichler, Bruce Robison, Rob Sherlock, Jessica Silguero, Sarah Skikne, and Mario Tamburri.
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