Review – From Surface to Seafloor: Exploration of the Water Column

[from Deep-Sea Life Issue 14]

Review – From Surface to Seafloor: Exploration of the Water Column

Aria Ritz Finkelstein

September 23, 2019

We still have much to learn about the dynamics and structure of the water column from the surface of the sea down to the seafloor. Our knowledge of the organisms that populate is far from complete, as is our understandings of how human activities will influence it. Recently, NOAA held a workshop with the goal of answering a number of questions: What lives in the water column? What are the “biodiversity, biogeography, ecology, and behavior” of organisms in the water column, and what is its structure? Second, what is the water column’s structure? How do anthropogenic activities influence this structure and these organisms? Finally, how do we communicate the importance of this knowledge to both the general public and policymakers?

The workshop’s result was a report outlining a broad, diverse range of research tools and potential collaborations. The report identifies unexplored regions, biodiversity hotspots, intersections between two very different environments, and places where the seafloor is already well understood as priorities for water column research. And, it lists the data to collect in order to understand both the current state of these regions and their variability across spatial and temporal scales.

There are a number of ways to collect each type of data—from chemical and physical characteristics to single cell biology to multicellular organisms all the way up to more complex data such as food webs, long-range tracking, and responses of animals to their environments. Long-term observation networks are important for understanding basic physical features—temperature, salinity, chemical levels, and so on. These can be ship-based, but they can also be floating, moored, or attached to stationary platforms. They can also take advantage of other already existing resources to piggyback research onto operations such as drilling ships. Remotely operated vehicles (ROV) are more useful for gathering in situ data about organisms—especially delicate ones—and the relationship between their distribution and physical and chemical conditions. There are many less traditional, autonomous systems too, including sensors mounted on animals, autonomous underwater vehicles (AUVs), and floating platforms with new capabilities like collecting eDNA samples. The main obstacles in the way of using these are battery power, biofouling, and the difficulty of ground-truthing, and these are areas that offer much room for innovation.

To map a way forward, the workshop participants developed a six-piece plan to develop a water column exploration program. First, the group will prioritize questions and key regions. Second, they will collect data from already existing and implemented sensors and expeditions. Third, they will use the prioritized questions to guide the development of new technologies. Fourth, they will dedicate ships to collect midwater samples. Fifth, they will standardize sampling and data management protocols. Sixth, they will prepare research infrastructure to respond quickly to anomalous events, because understanding the water column under perturbation or unusual conditions can be as useful as understanding its “normal state.” Finally, as important as these structural and technical questions are, perhaps the most important task the workshop participants discussed is the work of communicating the importance of their research to the general public and to policymakers.


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