{"id":255,"date":"2019-05-10T05:43:44","date_gmt":"2019-05-10T09:43:44","guid":{"rendered":"https:\/\/www2.whoi.edu\/staff\/rgast\/?p=255"},"modified":"2019-06-04T14:46:53","modified_gmt":"2019-06-04T18:46:53","slug":"making-lemonade","status":"publish","type":"post","link":"https:\/\/www2.whoi.edu\/staff\/rgast\/making-lemonade\/","title":{"rendered":"Making Lemonade"},"content":{"rendered":"

When life gives you lemons, make lemonade – or at least try to.<\/p>\n

I know I keep talking about this (and I promise this will be the last time), but when your CTD breaks, and the backup CTD refuses to work properly, how do you collect water for a project based entirely on collecting seawater?\u00a0 And not just surface water, but water at depth.\u00a0 And you don\u2019t even know if there is anything of interest to be collected at depth because the CTD package isn\u2019t giving a profile of the temperature, salinity and fluorescence.\u00a0 This cruise has been a challenge not just for us, but for the technical support on the ship.<\/p>\n

As you already know, we are using a bucket to collect surface water.\u00a0 We bought these in Punta Arenas the day that we were leaving port.\u00a0 Oceanographers should always have at least one clean plastic bucket with a sturdy metal handle.\u00a0 There are ones on the ship, but they often have oil or other chemical residues which will harm the organisms we are trying to study.\u00a0 We joke about using the bucket, but it\u2019s not always easy to do \u2013 particularly in 30-40 knot winds and blowing snow.\u00a0 Getting the bucket down to the water without the wind taking it for a ride can be a challenge, and repeatedly hauling it up from a churning sea is a workout.<\/p>\n

\"\"<\/p>\n

We have had company on deck on several occasions \u2013 birds!\u00a0 But only when it has snowed.\u00a0 We come out on deck and there can be up to 20-30 birds sitting around.\u00a0 Most of them are these lovely snow petrels, and there are sometimes 1-2 larger gulls.\u00a0 You\u2019ll also find their footprints in the snow all over the ship.\u00a0 They aren\u2019t terribly concerned about us, and I think they are using the ship as a resting spot from the wind.\u00a0 But I don\u2019t really know why they would need it.\u00a0 If you are following our cruise track you\u2019ll notice that we are almost always near land.\u00a0 (I\u2019ll explain more about why in a future post.)<\/p>\n

\"\"<\/p>\n

So, we\u2019ve got surface water pretty well sorted out, but what about that deeper water?\u00a0 During the spring and summer a peak of fluorescence is observed at about 50-70 meters below the surface.\u00a0 We are interested in knowing whether that exists now, in the late fall, and at what depth it is located.\u00a0 We\u2019d like to test for mixotrophs there as well, because the organisms may respond differently.\u00a0 We\u2019ve been using an instrument called a PRR (Profiling Reflectance Radiometer, that’s Kevin and Wade getting ready to do a deployment) to measure the light quality through the water column, and Wade figured out a way to convert the data to estimate the fluorescence.\u00a0 This has given us a glimpse at a subsurface peak, but it\u2019s only appeared twice (out of 5+ deployments) and it\u2019s at 12-15 meters.\u00a0 It\u2019s also not very big.<\/p>\n

\"\"<\/p>\n

The electronic technician onboard managed to get fluorescence detection on the mini-CTD instrument package to work, so we have been using that as well to look at the water column.\u00a0 Again, not much evidence of a subsurface fluorescence peak.\u00a0 And perhaps this is not surprising as there have been several storms over the past two weeks which will mix the surface water column.\u00a0 Also, there has not been much bright sun, which may result in the photosynthetic organisms remaining closer to the surface in order to get what little light is available.<\/p>\n

\"\"<\/p>\n

But how would we sample the peak even if it was there?\u00a0 Well, one of the marine technicians managed to modify the firing mechanism for a Niskin bottle from the large rosette (a 12 liter bottle \u2013 coincidentally, our bucket holds that same amount).\u00a0 He also made it possible to attach the bottle to the winch wire, and found a messenger (a heavy metal weight) that slides down the wire to trigger the closing mechanism.\u00a0 We first do a water column profile with the mini-CTD, then attach the modified Niskin bottle to the winch wire above the CTD (for weight).\u00a0 We can tell how deep it goes by \u2018zeroing\u2019 the winch wire with the bottle at the surface.\u00a0 We have collected subsurface water this way twice, although neither subsurface peak was very large.<\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

As I said before, it has taken a major combined effort to come up with a workable solution.\u00a0 It\u2019s better than the alternative of no water and no idea of whether there is a fluorescence peak below the surface.<\/p>\n","protected":false},"excerpt":{"rendered":"

When life gives you lemons, make lemonade – or at least try to. I know I keep talking about this (and I promise this will be the last time), but when your CTD breaks, and the backup CTD refuses to work properly, how do you collect water for a project based entirely on collecting seawater?\u00a0…<\/p>\n","protected":false},"author":46,"featured_media":260,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[3],"tags":[],"_links":{"self":[{"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/posts\/255"}],"collection":[{"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/users\/46"}],"replies":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/comments?post=255"}],"version-history":[{"count":3,"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/posts\/255\/revisions"}],"predecessor-version":[{"id":286,"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/posts\/255\/revisions\/286"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/media\/260"}],"wp:attachment":[{"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/media?parent=255"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/categories?post=255"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www2.whoi.edu\/staff\/rgast\/wp-json\/wp\/v2\/tags?post=255"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}