Category Archives: Oceanic

Update: Fukushima Derived Contamination in Pacific Surface Water Up Until 2017

Northeast subarctic Pacific from the deck of the Canadian Coast Guard Ship J.P. Tully in September 2

By Jay T. Cullen

The purpose of this post is to summarize a recently published, peer-reviewed study that documents levels of Fukushima derived contamination in surface waters of the Pacific Ocean. This post is part of an ongoing series aimed at communicating scientifically derived information about the impact of the disaster on marine environmental and public health. Michio Aoyama and colleagues measured the activity of Cesium-137 (137Cs, half life ~30 years) and Cesium-134 (134Cs, half life ~ 2 years) in seawater collected from the western Pacific Ocean including waters off the coast of Fukushima Prefecture from 2011-2017. They found the following:

  • Contamination decreased dramatically and rapidly in waters offshore of the Fukushima Daiichi Nuclear Power Plant (FDNPP) from maximum values of ~3000 Becquerel per cubic meter (Bq m-3) of seawater in 2011 to values  in 2015-16 of ~2-3 Bq m-3. This precipitous decline is consistent with the ongoing but relatively low rates of release of radionuclides from the site compared to the bulk of contamination that was released in March-April 2011.
  • Levels of 137Cs close to FDNPP now are similar to levels of contamination present there before the disaster occurred (1.5-2 Bq m-3) owing to atmospheric nuclear weapons testing in the middle of the 20th century.
  • Levels in the western Pacific were around 1-7 Bq m-3 in 2011-2012 but stabilized at lower values in 2017.

Levels being measured in nearshore and offshore waters in the western Pacific near to Japan do not approach levels known to represent a credible risk for ocean or public health. These results in the western Pacific are consistent with what the Integrated Fukushima Ocean Radionuclide Monitoring (InFORM) project is finding in the eastern Pacific off of North America.


Aoyama and others recently published their study in the Journal of Environmental Radioactivity. The collected and analyzed surface seawater for the presence of radiocesium isotopes between 2011 and 2017 in waters of the western Pacific in the following locations:

AoyamaetalFig1.jpg
Boundaries of areas (boxes) sampled by Aoyama et al. (2018) in the western and central Pacific Ocean.

The activity of 137Cs and 134Cs in Bq m-3 with time that they found are summarized in the following figure:

1-s2.0-S0265931X17307750-gr2_lrg.jpg
Long term trends (2011-2017) in radiocesium activity in boxes defined in the first figure. Solid blue squares are 137Cs activity concentration and open red circles represent 134Cs.

The researchers found that in Box 2 (closest to the FDNPP) contamination in surface waters offshore were highest in early 2011 coincident with the largest releases from the site in March-April of that year when the vast majority of radionuclides were released to the atmosphere and directly to the ocean.  Values dropped dramatically so that by 2014-2016 levels were ~3 Bq m-3 and similar to levels of contamination measured before the disaster occurred owing to nuclear weapons testing that occurred in the 1950s-60s. Note that the concentrations of 134Cs diminish relative to 137Cs, and the red symbols on the figure diverge from the blue symbols, because 134Cs has an ~2 year half life and is decaying away from the environment much more rapidly. Indeed, it is becoming increasingly challenging analytically to detect Fukushima 134Cs in environmental samples.  Contamination farther offshore in Boxes 4-6 indicate that maximum levels of contamination from Fukushima approached by did not exceed 200 Bq m-3 in 2011 and are now ~2-3 Bq m-3.

Based on best estimates of how much radiocesium was released from FDNPP in March-April 2011 the authors used a model of the water circulation and mixing in the Pacific to predict the levels and movement of Fukushima 134Cs in the Pacific from April 2012 until October 2016.  The results of the modeling study are summarized in the following figure:

1-s2.0-S0265931X17307750-gr3b_lrg.jpg
Horizontal distribution of 134Cs from Fukushima for the period April 2012 to October 2016. Open circles represent observations/measurements of 134Cs while shading reflects model results.

What the model and observations indicate is that the bulk of contamination from the site went into the Pacific Ocean in 2011 and that rates of release from the site after that time are very small in comparison. Most of the Fukushima contamination is now in the eastern Pacific near to North America and that levels in behind the main body of contamination are difficult to detect.  Similarly, the lack of appreciable 134Cs and 134Cs/137Cs activity ratios close to FDNPP indicate that there is little evidence for ongoing fission in the reactors at the site as is commonly speculated by those with little scientific training.  The levels the scientific community is measuring close to FDNPP and those expected and measured in waters close to North America do not represent a significant risk to the marine ecosystem or public health.

The Fukushima InFORM project will continue its monitoring activities in the eastern Pacific until Spring 2019.

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Voyage Reflections

By Chloe Immonen
25 July 2018 @ 10:34

Ice in hand
Sea ice!

Unfortunately, shaft/cycloconverter (fancy pieces of machinery in the engine room) failures meant that science operations stopped a day early. We were forced to steam straight to Utqiagvik, Alaska (formerly Barrow) to avoid being stranded on a station in the middle of the ocean. Thankfully, this allowed us to spend that day packing up all of the equipment and get a good night’s sleep.

I’m increasingly aware of how incredibly rare it is for undergraduate students to participate in research cruises and I am even more grateful to have been given this opportunity. It is something I will cherish for a long time and I cannot wait to get back on a ship. I love doing science on boats. Despite rarely getting more than four hours of sleep at a time, being cloaked in endless fog, and missing three of the nicest weeks of the summer in Victoria, it was so worth it for this incredible experience of lifetime. The number of times I found myself BEAMING all alone, basking in how happy I felt, was a little ridiculous.

Laurier CTD
Preparing the CTD rosette for deployment.

All of the tough things about being at sea made the positive things that much more welcome. A day of sun, a whale sighting, making connections with people from all walks of life, pensive life chats at 04:30 staring into the still-lit horizon, dancing to Motown hits while sampling from the rosette, hot tub soaks sailing past the Aleutians, gaining practical skills and knowledge associated with jobs I want to pursue, the best chocolate cake I’ve ever had, getting to see sea ice in person, collecting rocks from the bottom of the Chukchi (yes, I have been told that getting excited about this makes me a nerd), and even the daunting/rigorous arctic crossing ceremony (this shellback is no longer a lowly tadpole!!) – all of these things outweighed the trying times by far.

Arctic clams
Clams and critters from Van Veen grab samples.

Final tally of wildlife seen:

  • >3 pods of grey whales in various locations
  • We almost hit a grey whale but the Captain saw it in time and Andre-Ann steered away perfectly!
  • Breaching grey whale
  • Countless bald eagles and a humpback whale coming into Dutch Harbor (seen from the hot tub)
  • Many puffins, parasitic jaegers, gliders, fancy arctic ducks
  • >4 albatross
  • Lots of benthic organisms pulled up from the ocean floor during Van Veen mud grabs
  • One adorable baby seal – the size of a loaf of bread!! It swam right up to the ship while we were on a station!

It was too foggy on our last day on the ship to helicopter off so we took our final glances of the CCGS Sir Wilfred Laurier from the “safety” of a Zodiac. I don’t think this is the last time the Laurier and I will cross paths.

Laurier zodiac

 

Read all of the posts from Chloe’s voyage from Victoria, BC to Utqiagvik, AK: Bitter-sweet Bon Voyage, Fueled for Exploration, Into the Storm, Friday the 13th was the Luckiest Day Ever 

Friday the 13th was the Luckiest Day Ever

by Chloe Immonen
16 July 2018 @ 13:19

Bering Sea
The Bering Sea

I am incredibly sleepy. We have now crossed into the Bering Sea after stopping in Dutch Harbour to pick up the American scientists. Leading up to Friday, July 13, I knew I had to finish taking 38 samples from the underway loop running through the ship, saving five samples for after Dutch Harbor. I had not had longer than two consecutive hours of sleep for the previous five days. I worked hard to finish off the last samples before finally having a bit of relaxation time with Gina and Shea. We hung out on the upper decks and the bridge, where we spotted loads of seabirds (puffins and albatross were the coolest) and tons of whales (orcas, greys, and humpbacks). The light was beautiful! Approaching the Aleutians, we hopped in the hot tub to watch the gorgeous scenery pass by. It was an amazing evening.

Hiking Dutch
Gina and Sarah hiking along the ridge in Dutch Harbor.

In Dutch, we made the most of being on land by going on one of the most stunning hikes I’ve ever had the pleasure of hiking followed by going to the Norwegian Rat bar in town.

The next two days were filled with preparing for the beginning of stations, helping the American scientists set up their lab space, and the Shellbacks (those science and crew members who have crossed the Arctic Circle by sea before) explaining some of the upcoming tasks for us Tadpoles (those science and crew members who have NOT crossed the Arctic Circle by sea before) to partake in. I’m pretty sure I’m not allowed to tell you any details, but the tasks have certainly consumed some of our time and energy.

Read more from Chloe’s journey across the NE Pacific: Bitter-sweet Bon Voyage, Fueled for Exploration, Into the Storm

Into the Storm

by Chloe Immonen
July 7, 2018 @ 18:02

I finally experienced seasickness. I had begun to think that I was just going to escape it altogether but after five days of spending hours on end focusing on filling resin columns, taping them carefully, moving around, and lifting heavy water samples in the lab with very few windows, all while the ship tilts back-and-forth to some pretty wild extremes finally got to me after all. Sorry to be graphic, but I threw up once, felt immediately better than I had all day, but not good enough to eat until over 24 hours later. I have been taking naps whenever possible and drinking lots of water, both of which have been helping immensely. I still don’t sleep more than two hours at a time, but my samples have been running much more smoothly now (thanks to Magic Wrap), so that is a bonus.

As I spend more time with the crew, I’m finding every single person to be so kind and enjoyable to be around. The crew on the bridge now know that I want to be informed whenever they see whales and it has already paid off! As we were deploying an underway CTD [a reusable instrument to determine ocean temperature and salinity] off the aft deck, a pod of sperm whales was out on the starboard side of the ship.

Everyone is also curious about the projects that I’m working on. I love getting to tell them and ask them about their lives and their rolls on the ship as well. It seems like quite the crazy life they all lead. Most of the time, they work four weeks on, and four weeks off, but the Arctic voyage is six weeks on, and six weeks off. My favourite question to ask is what everyone likes to do in their time off because the answers are all so unique – from scuba diving and foraging for mushrooms to pottery and horseback-riding, everyone has a cool hobby to entertain them in their long stretches of time off.

Laurier fjordShea and I tended to the incubations on the helicopter deck for a couple hours this afternoon. I am stoked to be gaining skills in his line of work. The rest of the time, I was running my own samples, or sleeping with one break for dinner (feeling good enough to eat 😊 ).

Today marked the beginning of the on-board bingo craze. Nearly every person on the ship participates, they announce ~15 numbers per day just after lunch and each round, they go for a different shape (horizontal or vertical lines, wine glass, cactus, blackout, etc). The prizes are quite extravagant – there’s an expensive coffee-maker, high end scotch, and camping equipment – just to name a few!

Tonight is another movie night with unlimited popcorn. We are watching a film called ‘Annihilation’. I am mostly going to attend for the popcorn and the extra-strong G&T’s.

Not too much else to report here! I’m still having a wonderful time at sea regardless of feeling ill and not getting much sleep.

 

Read more from Chloe’s voyage to the Arctic: Bitter-sweet Bon Voyage, Fueled for Exploration

Fueled for Exploration

by Chloe Immonen
9 July 2018, 7:30 pm

WWII plane-1
The RAF Dakota 576 crash site just outside of Port Hardy.

Yesterday I awoke in Port Hardy and was told we would be spending the day docked while the ship refueled. This meant that 13 hours was needed to top up the measly one-million-liter diesel tank beneath us. This also meant that the crew and supernumeraries (aka the scientists) were allowed to disembark and explore Port Hardy. My roommate, Gina, and I went for a hike, recommended by a local, to the site of a WWII plane crash. The hike was through a lush, muddy, and mosquito-ridden rain forest and it felt amazing to stretch our legs and smell some trees. Gina, a Vancouver Island native, told me which berries were safe to eat along the way and I tried salmon berries for the first time! Seemed like a genetically-modified cross between raspberries and oranges to me, but they were very tasty.

After returning from our hike, Shea and I left again to visit the hardware store to replenish some supplies we were both short on. In an attempt to solve my leaky column problem, I bought ten more rolls of electrical tape, and something called “Magic Wrap” which claimed to form a rubber casing around a cylinder and stay water-tight. I have now tried it out with the next seven samples and it seems to be working – THANK GOODNESS.

We then returned to the ship to assemble Shea’s incubator on the helicopter pad. His experiments are looking at the effect of increasing atmospheric carbon dioxide levels on phytoplankton growth. We bubble air with present-day atmospheric constituent concentrations (CO~ 410 ppm) and air with one of the projected constituent concentrations for the year 2100 (CO~ 750 ppm) into separate containers holding the same diversity of phytoplankton and we will soon see how the organisms react to increased levels of the greenhouse gas.

We still had a couple more hours to kill so I went for one last jog on land among the pretty rock faces and lush wildflowers along the highway. As we ate dinner, the ship started to move again which indicated it was time for me to get to work. I processed a few samples over the course of the night, waking every hour to check for leakage and to change out fresh carboys.

ARGO float deployment-1
Preparing the ARGO float for deployment.

I am getting more and more confident with the lab protocols, remembering the crew members’ names, and navigating routes around the ship. I am constantly in awe of the stunning scenery surrounding us. Watching the waves interact, the sky change colours at dawn and dusk, and keeping an eye out for whales doesn’t cease to entertain me. I remain endlessly grateful for the chance to fulfill one of my dreams and take this trip of a lifetime.

Speaking of dream come true, I am about to go take another sample, watch the deployment of an ARGO float, eat a strawberry tarte, and then watch the sunset from the hot tub. Goodnight!

Read more from Chloe’s journey on the across the NE Pacific: Bitter-sweet Bon Voyage