RamaCam - In situ holographic imaging and chemical spectroscopy for long term scalable analysis of marine particles in deep-sea environments

While modern day ocean sensors are capable of measuring the concentration of chemicals dissolved in seawater to such high sensitivities that we rarely need to sample them, many chemicals form tiny particles in seawater, often with diameters smaller than the width of a human hair, and these act as a blind spot for most of today's sensors. The only way to study these particles in detail, is to recover samples and analyse them in a laboratory. Marine particles include plankton, dead skin shed from whales and fish, faecal pellets as well as micro-plastics and other types of human litter. If you took a bottle of seawater from the surface of the ocean and compared it to seawater from the deep-sea, the number of large particles would be much higher in the surface water, because light from the sun provides energy that can be used by plankton, which form a large proportion of the particles where sunlight can reach within 200 m of the ocean surface. At the same time, we also know that most particles sink, and so it is important for us to understand why there are so few particles in the deep-sea, how much material is sinking to the seafloor, what it is made out of, how fast it sinks, and what proportion of it makes it back up to the sea surface or gets washed on-shore. The reason this is important, is that particles that sink to the seafloor are thought to play an important role in removing carbon from our atmosphere. At the same time, scientists are worried that litter and plastics may accumulate on the seafloor and damage the fragile seafloor ecosystems that exist at an average depth of more than 3800 m below the ocean's surface.

The aim of this project, is to demonstrate new ways in which we can improve our ability to study the distribution of different types of particles in the deep-sea. The sensor that will be developed will analyse large volumes of seawater, almost 2/3 of a drinks can a second, in order to gather data in the deep-sea where the relative number of particles is small. The sensor will count the number of particles that pass through it, study their appearance and also perform laser based chemical analysis to identify what these particles are made out of. An important aspect of this work is to achieve this in a compact, low power way. The last point is important to allow large numbers of this new type of sensor to be used to study vast regions of the ocean for several years at a time. This innovative work will be carried out by researchers based in the UK and in Japan, both island nations with a long history of marine research, who will combine their expertise to overcome the difficult challenges that are involved in achieving our goal. By helping researchers in the future achieve a better understanding how particles in the ocean behave, and this can in turn help our governments decide what kinds of policies need to be put in place to preserve our ocean and our atmosphere.

The challenges addressed by this project have a direct, long term impact on natural environment and resource management in the oceans, lakes and rivers. On decadal timescales, sustaining these environments and their ecosystems will contribute to the economy and social well-being of the general public through job creation (e.g. sustaining tourism and industrial activity developing resources) and security (e.g. providing clean/safe food and water, understanding risks posed by global hazards such as ocean acidification and climate change). On shorter timescales (5 to 10 years), monitoring the impacts of waste (e.g. carbon emission, micro-plastics) and industrial activities (e.g. deep-sea/coastal mining) on the biogeochemical cycles that sustain water environments can help ground estimates of the socioeconomic costs associated with anthropogenic activities through efforts such as those of Earth Economics [1]. This can be used to help governmental agencies formulate effective conservation and resource management policies. In the more immediate future (<5 years), the growing recognition of anthropogenic impacts on the environment and the need for sustained monitoring drives governments and industry services to consider the best practices for environmental monitoring. The associated costs are directly coupled to the technologies that can be adopted and deployed in mass to make observations at the required metrology, spatial and temporal scales. Efforts to define these parameters underpinned by the activities of groups such as GOOS [2].

This research will demonstrate key sensing concepts that will fill a gap in our ability to observe the abundance and composition of particles in natural water environments over the necessary spatial and temporal scales. While particles play a key role that influences biogeochemical fluxes in these environments, many types of particles, including biochemical essential ocean variables, minerals and micro-plastics, can only be monitored by recovering samples using oceanographic research vessels that cost ~£20k per day of operation, where routine monitoring efforts typically last several days to weeks and are carried out at least once a year. The short term impact of developing sensors to replace these efforts is a reduction of survey costs by reduced reliance on expensive research vessels. The longer term benefits are improved understanding of how particles influence biogeochemical processes. The research is a proof of sensor concept (TRL 4), where the most effective way to ensure its outcomes benefits the identified chain of impacts is to work closely with stake holders invested in the short term activities and impacts. These are identified as,
- technology manufacturers with a track record of making sensors widely available to the marine research community,
- commercial survey companies and statutory monitoring agencies who can establish operational protocols for use of the conceptualised sensor in order to accelerate the adoption of technology once it becomes available, and
- data handling groups who can define formats and metadata requirements to make data collected by the sensor accessible to its stakeholders.

Manufacturer can potentially benefit by commercializing the technology developed in this work. Survey agencies, in particular those in the commercial sector can benefit by becoming early adopters of the technology and working alongside researchers to develop best practices and establish survey protocols. Data handling groups stand to benefit by hosting data that is widely accessed and utilized by a broad range of research organisations, monitoring agencies and policy makers. In order to ensure that the opportunities to benefit from this research are realized, prominent groups active in these areas in the UK and Japan have been identified and approached, with several of these providing letters of support.

[1] http://www.eartheconomics.org/
[2] http://www.goosocean.org/