A list of publications related to each project can be found
at the bottom of their pages
The deep sea is the least explored environment on the planet and within it the hadal zone is clearly the last frontier. It is comprised of ~37 deep ocean trenches and troughs (6000 to 11,000 meters or 3.7 to 6.8 miles), and it represents the deepest marine habitat on Earth, accounting for the deepest 45% of the global ocean. Because of the immense technological challenges of working at these depths most studies were very limited. With the advent of state of the art submersibles and remotely operated vehicles we are part of a new era of hadal science. Our work investigates the distributions of hadal animals in relation to depth, food and other variables and also seeks to work out the trophic relationships of hadal food webs.
Even within the understudied trenches the water column habitat is even less studied than the seafloor. Most tools developed for hadal research operate on the bottom and clearly, we still have much to learn there. However, the water column connects the trench seafloor to the overlying surface ocean and it is likely that many hadal animals have larvae that are transported in the water. In other deep-sea habitats, we know that midwater life actually increases near the seafloor, likely because sinking detritus (food) accumulates on the bottom. It is unknown if this occurs in trenches or if earthquakes and underwater landslides (turbidity flows) also affect the water column. To answer these questions and many more, we are collaborating on a free-falling profiler that will study the physics, chemistry and biology of the trench water column.
Small fish, shrimps, and squids (micronekton) at midwater depths form deep ocean sound scattering layers that can undergo diel vertical migration (DVM), a coordinated movement up into shallow waters to feed at night and descending down several hundred meters during the day. These animals provide critical ecosystem services as a forage base for commercially important top predators and charismatic marine mammals and contribute to carbon sequestration through their active vertical migrations. Yet, many of these animals remain understudied and it’s unclear how the patterns and behaviors of midwater populations will change in response to environmental disturbances like deep-sea polymetallic nodule mining.
This activity may commence as early as 2022 in the Clarion-Clipperton Fracture Zone (CCZ)- an area in the central North Pacific Ocean that spans a width equal to the continental United States. How might deep scattering layers be affected by mining-related sediment plumes in the water column? How do these layers vary naturally across the CCZ prior to mining? This poses a major gap to our knowledge considering the significant ecological value of midwater populations.
Understanding the role that an organism plays in a community necessarily includes knowledge of what it eats, whether its prey change in time or space, and how much matter and energy individuals and populations consume. This species level information can in turn be integrated to form food webs that can organize our understanding of ecosystem function. Our research has ranged from diet studies to the use of compound specific isotopic analyses to understand the importance and diversity of food sources to deep-sea ecosystems. In particular our food web research seeks to understand how communities and their food webs are connected from the surface to the seafloor. READ MORE