Oceanographers plan cruises very carefully to meet the scientific goals of the project. In the Southern Ocean, those plans can be foiled by weather, as well as the usual difficulties of gear failures. For salps, there is the added challenge of their episodic and patchy patterns of distribution and abundance. Regardless, we have made careful and detailed plans for sampling during our “November Salp Survey” cruise (LMG11-10). Keep reading for (lots) more information and see the image of our station locations in the Western Antarctic Peninsula region.
Station plan:
At each station, a standard set of deployments will include one CTD cast with Niskin bottle water sampling to a depth of 750 m or the bottom (estimated time ~ 1 hr); one 1-m
2 MOCNESS cast to 1000m (~ 4 hr); and one IKMT tow to 175 m (~ 1 hr).
Net tows will be done at night (dark) when logistically possible, but we will not delay station operations to ensure this.
Small boat (Zodiac) operations: We will carry out small boat operations opportunistically and on a site-specific basis. These will include hand-net or bucket collection of salps and small-scale acoustic surveys. Estimated time for each small boat operation is 6 hrs. Eight operations are planned throughout the cruise.
Deep MOC-1 tows: MOCNESS tows will be carried out to near-bottom depth (2,500 m) at deep offshore stations. Estimated time for each tow is ~7 hrs. Deep MOC-1 tows will be conducted at four offshore stations.
Acoustic Towfish: The Biosonics towfish will be deployed for survey transects between stations for a 2 hour period at a speed of ~ 5 knots, depending on sea state, presence of animals in net tows, ice conditions, etc. The timing and duration of these tows may change due to shipboard operations and the station schedule.
Cruise plan: The cruise track will include 24 stations, each with a standard array of deployments; 8 sites for small boat operations; and 4 deep MOCNESS tows. Our cruise plan has been designed based on information available at this time and per RPSC estimation that time available for our use may total 17 days (408 hrs).
30 Oct Leave Punta Arenas
3 Nov Cape Shirreff
5-7 Nov Palmer Station
8-24 Nov Salp Survey [17 days total]
25-26 Nov Palmer Station
30 Nov Arrive Punta Arenas
The course under ideal weather conditions and ship operations will require 135 hrs steaming and 214 hrs station work, for a total of 355 hrs (Table 1). This leaves 53 hrs (2 days) for weather and other possible delays. We will drop deployments or stations as necessary to accommodate longer delays.
Station 1: A first station will be occupied near Cape Shirreff, Livingston Island after the ship is done offloading the field camp (estimated 03 Nov 2011). Deployments will include CTD, MOCNESS, and IKMT tows. Station time estimated ~ 6 hrs.
Stations 2 – 22: After departing Palmer Station, we will follow a cruise track offshore and sample at Stns. #2, 3, 4. We will steam northeast to sample at Stn. #5. The cruise track then takes us to the stations offshore of the South Shetland Islands (Stns. #6-12), turns back to sample the Bransfield Strait (Stns. #13-20) and coastal waters of the WAP (Stns. #21, 22).
Stations 23 – 24: Time and weather permitting, we will steam farther to the SW to sample shelf and slope waters at Stns. #23-24, before returning to Palmer Station by 25 Nov 2011.
Ann Bucklin is a professor and head of the Department of Marine Sciences and director of the Marine Sciences and Technology Center at the University of Connecticut. She received a B.A. in Biology from Oberlin College and the Ph.D. in Zoology from the University of California, Berkeley. The theme underlying her research interest – spatial and temporal patterns of molecular genetic variation in marine organisms – developed from her early studies of sea anemones. Her current focus is the molecular systematics, phylogeography, and phylogenetics of marine crustacean holozooplankton (i.e., animals that spend their entire lives in the pelagic zone). Recently she was a lead scientist for the Census of Marine Zooplankton (CMarZ), an international initiative during 2004-2010 to study global patterns of zooplankton diversity. She has participated in 21 oceanographic research cruises, serving as chief scientist for six of these. The Antarctic Salp Survey is her first field experience in the Southern Ocean – a long-awaited and very welcome adventure!
Peter Wiebe grew up near the seashore in central California, where he developed a love for and a curiosity about the oceans at a very early age. As a youth, he spent hours free-diving in the Monterey Bay area; he assembled his first SCUBA gear in 1954. After undergraduate studies in Northern Arizona, a region whose oceans disappeared 40 million years ago – thus making him too late to study them first hand – he went to southern California and the Scripps Institution of Oceanography to obtain a Ph.D. in Biological Oceanography. Now an Emeritus Senior Scientist at the Woods Hole Oceanographic Institution, his interests have most recently been focused on the dynamics of zooplankton populations on Georges Bank and on krill living on the continental shelf region of the Western Antarctic Peninsula. His area of expertise is in the quantitative population ecology of marine zooplankton, including small-scale distribution and abundance of zooplankton, biology of cold-core and warm-core Gulf Stream Rings, and determination of zooplankton biomass, abundance, and size by acoustical backscattering. He has been involved in the development of a number of instrument systems, including the Longhurst-Hardy Plankton Recorder; Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS); Bioacoustic Sensing Platform And Relay (BIOSPAR), a free-drifting buoy; and three towed body systems: Greene Bomber and two versions of the Bio-Optical, Multifrequency Acoustics, and Physical Environmental Recorder (BIOMAPER; BIOMAPER-II).
Paola Batta-Lona is a PhD student at the Department of Marine Sciences at the University of Connecticut. She earned the M.Sc. in Oceanography at UConn in 2005 and a B.S. in Biology with Honors from the Autonomous University of Baja California, México. Her research interests are the genomics and genetics of Southern Ocean zooplankton, with an emphasis on population genetics and environmental genomics. Salps are the main focus of her doctoral research; she is studying their population genetics and gene expression patterns as a result of its interaction with the changing environment in the Southern Ocean. This is her seventh oceanographic research cruise, including previous Antarctic expeditions on German, Japanese, Norwegian research vessels. This cruise will provide useful and exciting new data to investigate and learn more about the population dynamics of the Southern Ocean salp, Salpa thompsoni.
Chelsea Stanley is an Acoustic Research Technician for the Department of Fisheries and Oceans (DFO), Canada. After pursuing a B.Sc. in Biology from the University of Victoria and a diploma in Environmental Technology, she began to work for the DFO, with interests in fisheries and plankton hydroacoustics and marine mammals. She has diverse oceanographic research experience, including collection and analysis of acoustic data using primarily a Simrad EK60 echosounder; calibration of ship-mounted acoustic equipment; sorting, identification and sampling of trawl net samples (including fish and invertebrates); plankton sampling; CTD and rosette operations; and oxygen titration; and ammonium and salinity analysis. To date, she has spent more than 400 days at sea. After spending time in the Pacific Ocean (off the coast of North America) and the Beaufort Sea (in the Canadian Arctic), she is excited to be in the Antarctic and to be a participant in this year's Salp Survey cruise.
----------------------------------------------------------------------------
Our team has gathered in Punta Arenas, Chile, where the R/V Laurence M. Gould is docked to prepare the ship for the cruise. We are preparing our laboratories, aquariums, and field sampling gear for action. We are almost ready to go!
The overall objectives of this effort are to examine genome-wide patterns of gene expression, target gene expression levels, and patterns of population genetic diversity and structure of the Antarctic salp, Salpa thompsoni in relation to biological and physical environmental parameters in the Western Antarctic Peninsula region.
Major activities: Four people will deploy for this project. High-frequency acoustics data will be used to provide information about the distribution of salps, krill, and other zooplankton. Sampling from shelf and oceanic waters between 0 and 2,000 meters will take place at selected stations using a 1-m
which is a similar principle found in squid.
The distribution of these muscle bands is very useful to identify different salp species. Each species consist of two forms; the solitary and the aggregate. The solitary form as the name indicates lives on its own (upper picture), whereas aggregate forms lives in chains consisting of 100–150 members (lower picture). They can form large swarms consisting of thousands of individuals.
Salps and krill
Previous studies have suggested that salps and krill have a tight relationship, since they consume similar food organisms and represent potential competitors for plankton. However, salps tolerate higher temperatures than krill. In the winter, when the sea ice is formed, the krill in Antarctica eats algae growing underneath it. The sea ice will decrease if temperatures of the Southern Ocean continue to increase. Consequently, the ice algae, a valuable food resource for the krill particularly in winter, will be less abundant and affect krill survival. Since salps are able to survive at higher temperatures than the Antarctic krill, the salps may then favour a warmer climate and gradually dominate over krill as a major species in the Southern Ocean.
(Text by Ann Bucklin and Paola Batta Lona, UConn; Pictures by Larry Madin, WHOI)