The most unexpected thing about the ocean is that it breathes…. heavily. How and why? Well that’s what we’re here to find out. Most of us have some understanding and contribution to respiration. Anyone with any modicum of sense takes advantage of it to avoid falling apart and decomposing. When we respire too much and/or too quickly, it puts us in a rather dizzy, spaced out sort of place – often referred to as VERTIGO and not to be confused with our reputable band of scientific individuals.
Nevertheless, notwithstanding and consequently, respiration – the use of oxygen (O2) with the production of carbon dioxide (CO2) – is a fortunate pastime for us mere mortals and our trophic brethren. When appropriate food is in plentiful supply, respiration drives our metabolism and the ability to do stuff – like build our magnificent frames and keep them in some sort of functioning order. It is not only a fundamental process to most life forms on planet earth, but a rather topical issue for mother nature’s top predator when they ponder such planetary processes as the carbon dioxide pool and global warming. These deliberations have been the source of mass debate and many protests from vegetarian, tofu licking, weak tea drinking, sandal wearing, tree hugging, carbon dioxide producing, oxygen depleting individuals, to the more informed scientifically inquiring efforts of ventures such as our wee band of Cafe Thorium infused, scientifically challenged individuals.
Thus studying VERTical exchange In the Global Ocean (VERTIGO) was considered a worthy objective for pushing back the front ears of science to reveal the transformation processes of carbon produced in the upper ocean while traveling to the deep. For those fortunate enough to read the outstanding articles from this and the 2004 investigation – particularly the article “Disappearances can be deceptive”, you will probably have some inkling of our mission:
“To boldly measure what no-one has measured this properly, accurately and completely – at this time, in these spaces, with so many mooring deployments and samplings with so little sleep – on planet earth….before.”
The last trip for me commenced with an awful mess, as my colleague’s appendix exploding prior to departure – leaving the offending individual in some state of disorder and an extended meal ticket in Honolulu hospital (Figure 3A). Consequently, the author was thrust forth into virgin scientific territory as the solo entrant of the group, vowing never to return for more punishment again. The transgressing individual – who shall remain nameless – somehow convinced me to return as wet nurse and the promise of a more relaxed and exhilarating excursion. Taking all precautions to keep the pictured individual intact for the pending trip, I inadvertently managed to become a member of the heavy breathing community and contribute more to the carbon dioxide pool in 1hr than I would normal produce in a month. This I managed by unwillingly, unluckily – and accidentally I might add – feeding a hungry bulkhead door (Figure 3B) with my small appendage (Figure 3C). Although this has provided much entertainment to my colleagues it also honed the Captain’s nail lancing skills – a delicate, quiet mannered, but considerably muscular two hundred pound nurse, sporting a beard.
However, I transgress. Splinted for action I thrust myself forth into the oceanographic frontier – pinky raised – to measure the degree of heavy breathing in the ocean. Our group is doing this by firstly determining the amount of carbon dioxide fixed in the upper ocean by microscopic plants. In this process – known as photosynthesis – light energy is used to convert C02 and other nutrients to the necessary cellular bits for having a splendid, yet delicate plant life. A by-product of this activity is oxygen; a somewhat important compound for most of life on Planet Earth. Photosynthesis generally happens in the well lit, yet relatively thin surface skin of the ocean (at this site, the top 60 m – 1 % compared to the 5000m of ocean beneath). We are measuring photosynthesis by determining the amount radioactively labelled carbon dioxide incorporated by these plants (phytoplankton) at various depths using a deck incubator (Figure 4). The phytoplankton are collected by filtering the water after 24 hrs (Figure 5).
This ‘primary production’ is only the start of the food chain, leading to – you guessed it – ‘secondary production’. Secondary production includes a ravenous bunch of individuals of micro and macroscopic inclination (vegetarians, carnivores, omnivorous and even in some cases coprophages – definition withheld). This can eventually lead to more robust creatures such as whales. During these production processes a whole size range of doo-doos, dead bodies and detritus must be taken care of in the grand cleaning scheme of life. Therefore, our group is also determining respiration rates of bacteria below the euphotic zone (not to be confused with the euphoric zone, which is the place where oceanographers go when they reach dry land). The death zone is where particulate organic carbon (POC – dead stuff) is remineralised (decomposed) on its trajectory vector (funeral precession) into the abyss (vast cemetery in the deep).
The majority of these experiments make use of tracing oxygen depletion (respiration to CO2). We have several different types of experiment to determine this: (1) By collecting water from a series of depths, incubating these in the dark for 48 hrs, and determining the difference in oxygen concentration by Winkler titration (Figure 6); (2) Monitoring oxygen depletion in the water column using mooring respiration chambers at fixed depths (Figure 7); (3) Monitoring oxygen depletion in sediment traps (Figure 8). A further experiment is planned to determine the respiration rates at a range of depths on filter concentrated samples collected using MULVS (Dr Jim Bishop’s Magnificently Underrated, Large, Vacuum-cleaning System). Additionally, for those of more biochemical disposition, we are collecting samples for laboratory determination of the Electron Transport System (ETS) activity (a proxy for respiration potential) and bacterial ecto-enzyme activity (enzymes released externally which are used to dissolve organic material).
Our experiments form part of the picture in determining the objectives of VERTIGO. Until these, and our colleagues, datasets have been appropriately masticated and expectorated in an acceptable form, the actual heaviness of the oceans breath will have to wait. Our results may indeed one day be put in perspective to the exhalationally audible utterance of Planet Earth to our striving dominance of its lands, oceans and sky. As long as we don’t induce planetary sneezing fits we should be OK.
— Mark Gall