What a difference a day makes! Our weather was absolutely tropical today. We have been working at our Station #16 throughout the day. We are protected by surrounding islands in relatively shallow water (about 500 m). We have had the luxury of working steadily throughout the day, without the down-town necessitated by waiting for workable weather.
So what did we do today? We collected zooplankton in IKMT and MOCNESS tows, and then worked quickly to observe and measure the living organisms and also prepare, process, and preserve samples. Here is a sampling of our work on board the LM GOULD.
A) When the MOCNESS is recovered after a tow, 3 or 4 people – including scientists and technicians – are needed on deck to wash down the nets while they hang of the stern gate, and then lift the cod ends over the gate, where they are detached from the net.
B) Each of the nine cod ends is brought into an “aquarium room” with running sea water, where the zooplankton sample can be processed. Paola is using a seawater hose to wash the cod end after the sample is removed.
C) The catch from one net: we have been sampling dense swarms of Southern Ocean krill in the surface layers (above 50 m), especially during the night. The bright red color is characteristic of krill; if you look closely you can see that their guts look greenish – they have been grazing on phytoplankton. For more about other zooplankton we have caught, see Melissa Patrician’s blog for today at http://aleslab.blogspot.com/. Be warned, it’s a quiz!
D) Each step in the processing of samples is recorded, with separate logsheets for each procedure or analysis. We keep track of all the collection information (called “metadata”) for each sample. Here Melissa M. is keeping track of specimens removed from the samples.
E) The sample is pourted from the cod end into a device that divides the sample into equal halves, so they can be shared between the science teams and preserved for different types of analyses. Joe is holding the “box splitter”, while Paola pours out the sample.
F) The box splitter is rocked back and forth to separate the sample into two chambers, which can be poured off separately. Joe is splitting the net sample.
G) Each half of the sample is washed into a sieve to remove the sea water. The zooplankton can then be washed into a plastic sample jar. Paola demonstrates our sieving technique, with a seawater wash bottle.
H) One half of the sample is preserved in formalin for later identification of species and determination of their abundance or concentration in the volume of water sampled by each net. Melissa preserves samples in buffered formalin, working in a fume hood in the ship’s hydrolab.
I) Living specimens of species of interest – including salps, krill, jellyfish, comb jellies, chaetognaths, amphipods, and many other species of diverse animal groups – are removed from the samples for special analysis. Ann is measuring individual alive-and-kicking krill inside the “freezer van” on the LM GOULD, before flash-freezing them in liquid nitrogen for genetic analysis.
J) The specific gravity of specimens of a variety of zooplankton groups is being measured by Joe Warren’s team. Katie is setting up the experiment in a ship’s “cold van”. For more explanation about this study, see Joe Warren’s blog for November 14th at http://aleslab.blogspot.com/.
We can only hope for more lovely work days like today, but the weather forecast suggests that the Southern Ocean may have something else in store for us. Here we go again!
-- Ann Bucklin (University of Connecticut)