{"id":99,"date":"2010-12-31T15:53:00","date_gmt":"2010-12-31T19:53:00","guid":{"rendered":"http:\/\/web.colby.edu\/colbyatsea\/?p=99"},"modified":"2011-01-06T12:12:21","modified_gmt":"2011-01-06T16:12:21","slug":"so-much-water-so-little-time","status":"publish","type":"post","link":"https:\/\/web.colby.edu\/colbyatsea\/2010\/12\/31\/so-much-water-so-little-time\/","title":{"rendered":"So Much Water – So Little Time"},"content":{"rendered":"
\"\"<\/a>

Great Belt Cruise Track v1.0<\/p><\/div>\n

We just got an email from Barney on\u00a0sampling logistics for the cruise. \u00a0You would think that researchers on an oceanographic research vessel floating in the middle of the ocean could have all the water they wanted whenever they wanted it. \u00a0 However, we have limited sampling opportunities while the ship is moving and we only have 36 days to make it to Cape Town. \u00a0The map to the right shows the current cruse track. \u00a0 The dots on the line are the sampling locations. \u00a0We are scheduled to sample 120 stations 52 nautical miles apart (6240 nautical miles, 24 days of steaming). \u00a0We must keep our average wire time (sampling time) to less than 8 hours for us to be able to get to Cape Town on 16 Feb.\u00a0\u00a0Barney divided up the 8 hours to match the sampling need of all the research groups on the ship. \u00a0 At this point, this is what a typical day will look like:<\/p>\n

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CTD Sampler<\/p><\/div>\n

1) Productivity casts (growth rate measurements) will always be pre-dawn, between midnight and 0400h. \u00a0A CTD sampler similar to the one shown right is lowered to depth at a rate of \u00a01 meter per second. \u00a0 A cast to 500 meters can take up to an hour depending on the time to trip (close) the bottles.<\/p>\n

2) Trace metal casts, Snatcher and McClane pump casts will always follow the CTD so folks know where to target the sample bottle depths of subsequent casts.<\/p>\n

a) The trace metal casts will go to 1000m and involve hanging individual Niskin bottles so this will take 1.5 hours provided the spool rate of that winch can reach 60m\/minute.<\/p>\n

b) Another sampler, called the Snow Catcher (aka “Snatcher”), will be deployed to ~75m, triggered, and recovered, taking another 30 minutes.<\/p>\n

\"\"<\/a>

McClane Pump<\/p><\/div>\n

c) McClane pumps will follow Snatcher casts. \u00a0These pumps collect the particles from a large volume of seawater by pumping water through a filter. \u00a0 It takes time to lower the pump to the sampling depth and more time to collect the sample. \u00a0Total time 4 to 5 hours. \u00a0This task is scheduled for every other day.<\/p>\n

3) Optics casts must happen as close to local apparent noon as possible and never outside the 1000h-1400h window in order to get maximum solar elevation.\u00a0 This task will take at least 30 minutes.<\/p>\n

4) Finally, additional CTD casts will be taken later in the afternoon. \u00a0 Time for deployment 1 hour.<\/p>\n

Total time for all the sampling is 7 to 8 hours per day. \u00a0This assumes that the ocean is accommodating. \u00a0 If seas get too rough to deploy gear we will simply have to keep moving. Cape Town is a long way at an average ship speed of 11 knots.<\/p>\n","protected":false},"excerpt":{"rendered":"

We just got an email from Barney on\u00a0sampling logistics for the cruise. \u00a0You would think that researchers on an oceanographic research vessel floating in the middle of the ocean could have all the water they wanted whenever they wanted it. … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":184,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"footnotes":""},"categories":[17554,17550,1178,17552],"tags":[],"_links":{"self":[{"href":"https:\/\/web.colby.edu\/colbyatsea\/wp-json\/wp\/v2\/posts\/99"}],"collection":[{"href":"https:\/\/web.colby.edu\/colbyatsea\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/web.colby.edu\/colbyatsea\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/web.colby.edu\/colbyatsea\/wp-json\/wp\/v2\/users\/184"}],"replies":[{"embeddable":true,"href":"https:\/\/web.colby.edu\/colbyatsea\/wp-json\/wp\/v2\/comments?post=99"}],"version-history":[{"count":12,"href":"https:\/\/web.colby.edu\/colbyatsea\/wp-json\/wp\/v2\/posts\/99\/revisions"}],"predecessor-version":[{"id":142,"href":"https:\/\/web.colby.edu\/colbyatsea\/wp-json\/wp\/v2\/posts\/99\/revisions\/142"}],"wp:attachment":[{"href":"https:\/\/web.colby.edu\/colbyatsea\/wp-json\/wp\/v2\/media?parent=99"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/web.colby.edu\/colbyatsea\/wp-json\/wp\/v2\/categories?post=99"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/web.colby.edu\/colbyatsea\/wp-json\/wp\/v2\/tags?post=99"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}