Rethinking ocean metabolism to improve our understanding of life underwater

May 29, 2024

New research is exploring the key concepts used in rapidly developing areas of marine research and improving our understanding of life underwater.

With support from the Ocean Frontier Institute’s (OFI) Visiting Fellowship program, Dr. Elis Jones, a philosopher of science, recently collaborated with Dr. Erin Bertrand from Dalhousie University to explore a concept used in marine sciences: ‘ocean metabolism’.

Dr. Elis Jones on a sampling trip with Dalhousie scientists during his OFI Visiting Fellowship. Photo by Sonja Rose.

"Ocean biogeochemists sometimes use the concept of ocean metabolism – but it is unclear what they mean exactly. Are they thinking of the ocean as an organism, as alive, or using it in a different manner?” explains Jones.

“The traditional scientific definition of metabolism refers to chemical processes within a living cell or organism. However, other disciplines like biogeochemistry use the term to describe processes outside of individual organisms. This raises the question – what does it mean for the ocean to have a metabolism?”

Reconsidering metabolic assumptions

As part of his fellowship research, Dr. Jones identified three key ways in which biogeochemical research challenges traditional assumptions about metabolism:

Metabolisms are not necessarily isolated to individual living organisms but can be shared and collaborative.

This is supported through various examples from the ocean, including microbes. Dr. Jones explains that ocean microbes undergo collaborative photosynthesis and respiration. This is similar to the way individual plant cells photosynthesize together to create the chemical energy needed for the plant itself to survive. In other words, large parts of the ocean have similar metabolic processes to plant cells.

Metabolism is not always internal to cells or organisms.

Iron is one of several examples which support this revised assumption. Levels of iron and other elements are very different in the ocean by virtue of the activities of marine organisms and their related processes. Organic molecules called ocean ligands can bind with iron to increase the solubility of the metal. While this process takes place outside of organisms, it plays an important role in their metabolism.

Metabolism can be partially independent of – and operate at a larger scale than – specific individual organisms.

Even large-scale elemental cycles, such as those of nitrogen and phosphorus, can be viewed as metabolic. Before life, the movement of these substances through environments was very different. Since life arose, many organisms have become heavily involved in moving these substances around the planet, including large numbers of ‘nitrogen fixing’ microbes in the ocean (and humans through the production of fertilizer). These biogeochemical cycles can be viewed as metabolic systems without a single organism as their host.

"Under these revised assumptions, the ocean can therefore be metabolic without being an organism,” says Jones.

A more holistic understanding of life in the ocean

Research suggests this view of the ocean as a metabolic system, rather than just a collection of individual organisms, helps provide a deeper understanding of ocean life. It highlights that the ocean is not just a passive body of water, but a highly structured and actively maintained system, which might cause us to think more carefully about how we interact with it.

"Reframing ocean metabolism offers us a more holistic and collaborative understanding of life on our planet," says Jones. In doing so, it offers possible areas for bringing together worldviews from diverse social groups.

It is also important to recognize that a system can be understood in multiple different ways, depending on the context. “The ocean might be viewed  as a metabolic system, or as several different systems, or as a collection of organisms and water,” Jones explains. “Science is often shaped by and for human interests, and so it is important to consider the diverse ways humans perceive and value the living world, and to try to incorporate this diversity into scientific practice, which has both scientific and ethical benefits.”  

The results of this fellowship are to be published in an academic journal later this year.

About Dr. Elis Jones

Dr. Elis Jones is a philosopher and sociologist whose research focuses on the role of values in scientific practice, particularly in the context of marine sciences.

With a multidisciplinary background spanning politics, philosophy, economics, and science and technology studies, Jones' work offers a unique perspective on the socio-ecological implications of scientific research. He is a PhD graduate from the University of Exeter (UK) and a postdoctoral fellow at the Konrad Lorenz Institute (Austria).