Category Archives: Video

T-TIDE student profile: Madeleine Hamann

PhD student Madeleine Hamann from the Scripps Institution of Oceanography is aboard the R/V Revelle for the T-TIDE leg 3 cruise and here she talks about her work and how studying math, science, and engineering has opened up a world of opportunity for her.

Falkor: Thanks for watching, part 2

We are all happy to be home, but had a great time doing science at sea on the Falkor. In the remaining hours of our T-Beam cruise, we were able to put together a video using one of our favourite songs: Tassie Whalers by The Overlanders (Pete’s uncle is one of the members!).

When not working, we were also hard at work trying to win the fitness challenge between the Revelle and Falkor crew. As the Revelle Leg-1 crew mentioned, it is important to keep healthy when at sea for such a long time. We tried our best and we even had a rowing competition with medals! Overall, the Falkor science and ship’ crew:

  • Ran 375km
  • Cycled 671km
  • Rowed 194.5km
  • Pullups 351
  • Pushups 7091
  • Situps 6347
  • Squats 1766
  • Dead lifts 70
  • Yoga 405mins
  • Burpees 850
  • Gun sculpting 23
  • Skipping 8400
  • Hoola hoop 30mins
  • Cheese 42
  • Bacon 20

Well done team!

 

Revelle: Breaking undersea waves make you a fish sandwich

The giant subsurface waves the T-team are studying are triggered thousands of kilometers away. After beaming through the Southern Ocean, the waves break against the continental slope, mixing the deep ocean. But, like bath-time with a hyperactive toddler and an especially slippery rubber ducky, these waves occasionally slosh up and over the edge of the tub. In the relatively shallow waters of the adjacent continental shelf of Tasmania, a whole new set of phenomena takes place, one that ultimately influences both the growth of sea life and the carbon dioxide content of the atmosphere.

The ocean’s food web begins with the phytoplankton. These tiny, autotrophic organisms harvest energy from sunlight to produce sugars through the process of photosynthesis. The energy harvested from the sun by the uncountable swarms of natural solar cells is transferred on to the zooplankton, the tiny, heterotrophic grazers of the ocean. After chowing down on the phytoplankton, the zooplankton in turn become food for small fish, and small fish for bigger, and on and on all the way up to your tuna sandwich.

The team aboard the Revelle deploys the anchor weight of one of the T-Shelf moorings. Photo credit: San Nguyen

The team aboard the Revelle deploys the anchor weight of one of the T-Shelf moorings. Photo credit: San Nguyen

Photosynthesis is one of the great marvels of nature: the delicate, complex biochemical process ultimately responsible for 99% of life on the planet. The machinery that harvests energy from photons zipping past, called chlorophyll, as well as the precursors necessary for fixing inorganic carbon dioxide into organic carbohydrates, must be synthesized from compounds acquired from the environment. Since the demand is high in the sunlit surface ocean, those necessary nutrients are always in short supply. The rate of nutrient supply thus controls the productivity of the phytoplankton, and indirectly influences the ocean’s food web and it’s ability to take up atmospheric carbon dioxide. But what controls the supply of nutrients? That’s where the giant subsurface waves, and the T-Shelf project, come in.

In much the same way that turbulence in the ocean’s abyss mixes cold water with warm, controlling the ocean’s ability to transport heat, mixing at the boundary between the sunlit surface waters and the deeper, dark waters below controls the supply of nutrients necessary for photosynthesis. This happens because the vast, deep zones of the ocean are nutrient reservoirs, created by the biological recycling of organic material that rains down from above. These nutrients can be brought into the sunlit surface waters through a number of physical mechanisms. Recently, we have come to appreciate that an important, and poorly studied, pathway is through mixing and transport driven by breaking internal waves.

The T-Shelf program aims to understand the fate of internal tide breakers as they slosh onto the flat continental shelf. At less than 150 m, the depth of the shelf means that much of the water above receives adequate sunlight for photosynthesis. The phytoplankton there are limited by the supply of nutrients, and we think that much of the nutrient supply comes from the transport and mixing associated with these undersea breakers.

We have deployed a series of moorings to measure the breakers as they cross the continental shelf break and the continental shelf. These moorings are in many ways like the much longer and deeper moorings that make up the T-TIDE mooring array. But they differ in two significant aspects: first, the moorings carry instruments to measure the quantity of phytoplankton and the amount of sediment in the water. Second, we are measuring phenomena occurring on small scales relative to the deep array, and have instruments that measure the currents, temperature, salinity, phytoplankton, sediments, turbulence, and nutrients with very fine vertical resolution. The combination of the T-TIDE, T-Beam, and T-Shelf data will allow us to discriminate between mixing and transport from remotely generated internal waves, tracked by T-TIDE and T-Beam from south of New Zealand, and internal waves generated at the Tasman shelf break itself.

We ultimately hope to unravel the complicated puzzle of the relationship between breaking internal waves, nutrient supply, and the biological character of the local ocean offshore Tasmania. These same processes are likely to be responsible for driving the food web in many places in the ocean, and are yet another important, fundamental process in the wonderful, interconnected planet we call home.

Drew Lucas and Nicole Jones, Revelle

The team aboard the Revelle deploys the anchor weight of one of the T-Shelf moorings. Photo credit: San Nguyen

The team aboard the Revelle deploys the anchor weight of one of the T-Shelf moorings. Photo credit: San Nguyen

The team afixes instruments to a T-Shelf mooring. Pictured (L-): Josh Manger, Nicole Jones, Drew Lucas, and Tyler "Slappy" Hughen

The team afixes instruments to a T-Shelf mooring. Pictured (L-R): Josh Manger, Nicole Jones, Drew Lucas, and Tyler Hughen. Photo credit: San Nguyen

The Tasman Tidal Dissipation Experiment / Supported by the National Science Foundation

The Tasman Shelf Flux Experiment / Supported by the Australian Research Council and the University of Western Australia

Falkor: Stormy weather

With most of our field work on the RV Falkor located in the middle of the Tasman Sea, we have had our fair share of rough weather. We were able to hunker down (or escape) the biggest storms that rolled through, but sometimes we had to stop collecting data for a few hours. Below is footage of one time we were glad not to be on deck.

– Sam Kelly & Amy Waterhouse, Falkor

The Tasman Tidal Dissipation Experiment // Supported by the National Science Foundation

Revelle: Thanks for Watching!

We’re thrilled to be back at port in Hobart after a productive and successful 25 days at sea. We deployed a whopping 15 moorings in 10 days and managed to recover two moorings to re-deploy number 16 elsewhere. Years of planning have made this month of work in Tasmania possible and we’re thrilled that almost everything went off without a hitch.

Thanks for following us on our journey. Be sure to stay tuned for more updates from The Falkor and leg two of The Revelle! Here’s a special video from all of us on The Revelle Leg 1.

—Julia Calderone, The Revelle

The Tasman Tidal Dissipation Experiment//Supported by the National Science Foundation

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