2009 Shelfwide Cruise: July 18 - July 23

Daily Log

Jul 18, 2009 - Day 1

1600 -: (17 July 2009) Load ship, calibrate SeaBird CTD for oxygen, depart dock at midnight
0800 -: Approach Southwest Pass of the Mississippi River, 23 psu
0900 -: Collect series of salinities from 23 to as low as possible, 3 psu, for nutrient gradient
1130 -: Arrive station A'1, strong oxycline near bottom at 8 m, 0.5 mg/L
1230 -: Depart for next series of A transects
1600 -: Depart from end of A line to head to A7, southern end of A trans
1800 -: Jenn and Sam see a shark . Very low oxygen across most of the trans A, mostly less than 0.5 mg/L
2100 -: Blue crabs, Callinectes similis, both ovigerous females and males swimming at surface of the water avoiding low oxyen near the bottom 0.1 u2013 0.2 mg/L
2300 -: Nearshore station mixed; depart trans A to trans B, inshore end

Jul 19, 2009 - Day 2

0100 -: New day, new transect, low oxygen. Several jellyfish, Quinquecira quenqueloculina (?) in subsurface water. Some blue crabs, C. similis, at the surface
0200 -: A bit farther SE on trans B. Lots of sea nettles in the water. Smaller portunid crab at the surface. Low oxygen below. Small shark at B4; paired unidentifiable fish.
0400 -: Large needlefish at surface, B6.
0700 -: Low oxygen out to B9, almost 40 m
Thunderstorms as cold front approaches
0730 -: Out to B10, 50 m, just on edge of low oxygen, 1.92 mg/L. Close it off at 57 m
0800 -: Start on SE end of trans C, working towards shore. Hypoxia not as extensive in deeper waters on trans C.
1500 -: Within 25 m contour, hypoxia on trans C, 0.9 at C7
1600 -: *Station C6C* and successful box coring at C6B, Jenn for foraminiferans and Ling for diatoms
1900 -: Station C4 with close to anoxia. Successful box coring Jenn has samples for foraminiferans at a station not normally this low in dissolved oxygen. Crew change for scientists
2100 -: Nearshore, north end of trans C in 5 m, normal oxygen. Headed to D'1
2300 -: End of day, low oxygen

Jul 20, 2009 - Day 3

0000 -: Happy Birthday Melissa, wish you were here! Headed offshore on trans D'
0200 -: Severely low oxygen on many trans D' stations, 0.2 mg/L from 15 m to 30 m. Benthic eel, portunid crabs, and penaeid shrimp swimming at surface
0300 -: Still headed south, hypoxia now deeper than 30 m
0400 -: Out of hypoxia in 45 m water, headed west to trans D
0700 -: Station D5 on south end of trans D barely above 2 mg/L
0900 -: Arrival of Canadian Broadcast Corporation, Jackie Corkery, producer, documentary series, film and sound crew, for the coastal ocean portion of a 4-part series on the ocean. Landed at D3 via the R/V Acadiana
0930 -: Just in time to film box coring. All other stations on trans D until beach station below 0.5 mg/L, several with hydrogen sulfide in the bottom water
1500 -: Close off trans D in 5 m with 4.6 mg/L. Headed to E1 off Marsh Island
1800 -: Start nearshore on trans E
1900 -: Canadian Broadcast Corporation crew departs on the R/V Acadiana
2100 -: Little hypoxia so far on trans E, box coring on trans E, repeat E2A from 2008
2335 -: No hypoxia on trans E but consistent with SEAMAP contours from couple weeks earlier

Jul 21, 2009 - Day 4

0000 -: Headed west to offshore end of trans F, normal bimonthly transect
0100 -: Looking similar to trans D, well-mixed down to 12 to 15 m. Could this year be similar to 1998 when persistent winds from the SW pushed low oxygen mass to east in deeper water?
0250 -: Continuing trans F with bottom oxygen levels of approx. 4.5 mg/L. Marine forecast was wrong, sustained winds to 20 kn, seas up to 4 to 5 ft
0400 -: Continue with no low oxygen and high winds and seas
0600 -: Very thin lens of low oxygen at F2 and F1 off the Atchafalaya area
0800 -: F0 just near the Atchafalaya Bay/Gulf intersection [N.B. hypoxia in Atchafalaya Bay earlier: 16 July 2009: Dr. Brian Roberts, LUMCON, reported extremely low oxygen concentrations within Atchafalaya Bay below 1 mg/L, including F0. Several supersaturated surface waters.]
1030 -: Begin trans G through day to G6. Calms down for day crew. Only one station below 2 mg/L
1800 -: Head west to offshore end of trans H in 30 m
2000 -: Begin trans H on offshore end in 35 m.
2200 -: Seas rough up for night crew, 17 kn from south, 4 to 5 ft

Jul 22, 2009 - Day 5

0130 -: End trans H on inshore end in 8 m, no hypoxia, as low as 2.4 mg/L. Depart trans H and head to inshore end of trans I, still rough, mixing shallower waters
0300 -: Trans I seems to be well-mixed as well. No wonder, persistent 17-20 kn winds with 6 ft swells. Again, a gift from the sea goddess for the night crew.
0700 -: Well mixed nearer shore, but thin layer of hypoxia begins in 20 m out to 30 m
1245 -: Into deeper water on trans I (31 m) and out of hypoxic zone. Transit to offshore end of trans J
1500 -: Offshore end of trans J in 3 mg/L
1830 -: No low oxygen so far on trans J, seas calm down for night shift, finally!
2100 -: Sta J4, no low oxygen, box coring for forams and diatoms, 3 for 3, plus one to grow on.
2400 -: Finished with trans J, no hypoxia, headed west to trans K, inshore end

Jul 23, 2009 - Day 6

0130 -: Begin inshore end of trans K in 6 m depth off Cameron LA
0330 -: Midway on trans K, no low oxygen.
0730 -: End of trans K, no low oxygen
0800 -: Head to trans off Sabine, TX/LA border to finish out grid and look for any remnants of hypoxia from earlier in month and late June
0900 -: Offshore end of trans M, no low oxygen
1700 -: Inshore end of trans S northeast of Galveston, no low oxygen; finish off grid and look for any remnants of hypoxia from earlier in month and late June
2130 -: End of trans S, no low oxygen
2200 -: Heading to port, Cocodrie, numbers being calculated and explained and compared.
P.S. -: This is the end of our SILVER ANNIVERSARY cruise. The first shelfwide cruise was in 1985. Three participants from that cruise are on board for this cruise: Nancy Rabalais, LUMCON; Jim Lee, LSU; Sam LeBouef, LUMCON. Gene Turner from LSU was also present on the summer 1985 cruise.