CRUISE PLAN FOR CGCS SIR WILFRID LAURIER CRUISE, JULY 2003

(Dutch Harbor to Barrow, AK)

 

Jackie M. Grebmeier and Lee W. Cooper (Co-PIs), NSF-funded “An Arctic Environmental Observatory in Bering Strait, The University of Tennessee, Department of Ecology and Evolutionary Biology, Marine Biogeochemistry and Ecology Group, 10515 Research Dr., Bldg. A, Suite 100, The University of Tennessee, Knoxville, TN 37932; ph. (865) 974-2592; fax (865) 974-7896; email:jgrebmei@utk.edu; grant NSF-OPP 9910319

 

I. PURPOSE

 

Annual hydrographic and benthic sampling at select sites north and south of Bering Strait are part of our NSF-funded Bering Strait Long-Term Observatory project.  These studies extend our existing 19-year time-series of sediment flux measurements of dissolved oxygen, benthic biomass, and other chemical and biological parameters at productive benthic stations, both north and south of Bering Strait (Fig. 1) using the CGCS Sir Wilfred Laurier transiting through Bering Strait.  A major premise for our sediment-based work in the Bering and Chukchi seas is that appropriate chemical and isotopic indicators in the benthos and bottom waters in this shallow, productive continental shelf ecosystem can provide accurate indications of the locations of particulate deposition and overlying water column processes. We have taken advantage in our past work of the longer-term integration of oceanographic change that is reflected in many benthic indices, which might vary as a result of changes in particle sedimentation, the strength of pelagic-benthic coupling, changes in apex predator populations, or other physical and biological events.  The tools we have been using to evaluate possible changes in the Bering and Chukchi benthic ecosystem have included sediment oxygen demand, deposition patterns of the particle-reactive natural radionuclide 7Be, the stable carbon isotope composition of sediment organic matter, elemental carbon/nitrogen ratios, sediment grain size, as well as more direct benthic metrics such as macrofaunal biomass and community ecological structure. Annual July sampling since 1998 has been supported in collaboration with Dr. Eddy Carmack (IOS) and the Canadian Coast Guard ship Sir Wilfrid Laurier enroute to resupply communities in the Canadian Arctic.

 

In addition to the core LTO sampling, Dr. Jack DiTullio (University of Charleston) has been collaborating on the project since 2001 to investigate DMSP and sulfur cycling in the Bering and Chukchi seas. Several trace biogenic gases have been implicated in significantly affecting global climate change processes. Water collections during the cruise allow measurement of the production of dimethylsulfide (DMS), dimethylsulfoxide (DMSO) and their precursor dimethyl-sulfoniopropionate (DMSP by bloom-forming algal species during bloom periods during the cruise.

 

In 2003 we will place a mooring in the SLIP region southwest of St. Lawrence Island as part of a NOAA collaborative project with Drs. Jim Overland (Pacific Marine Environmental Laboratory, PMEL) and Terry Whitledge (University of Alaska Fairbanks, UAF).

 

II. CRUISE PLAN

 

Sampling is planned at 27 stations in the Bering and Chukchi seas, including 6 water column stations in transit from Dutch Harbor to the A-SLIP region (Figure 1) as part of the annual IOS sampling plan. The core LTO sites include 16 water column and benthic stations in areas A, B,

and D and 5 hydrographic stations in the US-portion of Bering Strait (Area C). In 2002 a mooring will be emplaced in the A-SLIP region near stations SLIP-1 and SLIP-2. The following information lists the planned participants and site of embarkation and disembarkation for the science party.

Figure 1. Station cruise track for July 2003 cruise on the CCGS Sir Wilfrid Laurier

 

 

 

A. Participants

 

Embark Dutch Harbor, Alaska (11/12July 2003) and Disembark Barrow, AK (22/23 July 2003), 12 days; total participants=10

1.     Dr. Jackie Grebmeier (F)-U Tennessee, Chief Scientist

2.     Jane Eert (F)-DFO/IOS Co-Chief Scientist

3.     Dr. Lee Cooper (M)-U Tennessee

4.     Arianne Balsom (F)-U Tennessee

5.     Rebecca Pirtle-Levy (F)-U Tennessee

6.     Betty Carvellas (F)-TEA teacher, Essex High School, Vermont

7.     David Brown (M)-TEA teacher, St. Peter School, Quincy, IL

8.   Dr. Peter Lee (M)-U of Charleston, SC

9.     Nathan Garcia (M)- U of Charleston, SC

10.  Sarah Thornton (F)-U Alaska Fairbanks

11.  Sigrid Salo (F)-PMEL (Dr. Jim Overland, PI)

 

B.  Science Station Planning

The following plan includes station locations for planned sampling (see Fig. 1):

 

1.     five long-term sites south of St. Lawrence in a “hot spot” region (A) where we have been observing bivalve and upper trophic level declines over the past decade [1 day sampling];

 

2.   deployment of NBS mooring near stations SLIP1 and SLIP 2 [<1 day, likely part of #1]

 

3.     four stations in the NE Bering Sea (B); [1 day sampling]

 

4.     five station CTD transect across Bering Strait (C) (U.S. waters only), with a 12 hr stop at Little Diomede Island in Bering Strait for site survey  [1 day total time]; and

 

5.     seven stations in the SE Chukchi Sea (D) as completed previously during 1998, 1999, 2000 and 2001 [2 days on-site sampling time total];

 

C. Standard Station Sampling Within The SLIPP01 Station Grid

 

1.  Water column CTD with rosette deployment for S/T/D and water column collections at 5 m depth intervals to bottom of deployment (one deployment). Note that the CTD should be collected continuously for physical oceanographic collections during the descent, then stopped at designated intervals on the ascent for water collections. Two bottom-water bottles will be collected for experimental purposes. Once returned to the deck, seawater will be collected from each rosette bottle on the CTD for the following measurements:

a.     nutrients-subsamples collected in acid-washed plastic vials and frozen shipboard

b.     chlorophyll-subsamples collected and processed shipboard on a Turner fluorometer

c.     oxygen-18-subsample collected in glass vials and sealed for land-based analyses

d.     DMS-seawater subsamples filtered to measure DMS back on land using cryogenic purge and trap gas chromatography later in the land-based laboratory (DiTullio)

e.     algal species-subsamples collected for HPLC pigment analyses.

 

Table 1. LTO station locations to be occupied in 2003 (note BS stations are part of  IOS hydrographic sampling where DMSP samples are also collected.

Station

(2003)

Historical

Station

Latitude

(°N)

Longitude

(°W)

Depth (m)

Sampling

BS-1

same

56.312

-172.824

 

water

BS-2

same

56.418

-172.793

 

water

BS-3

same

56.476

-172.779

 

water

BS-4

same

56.546

-172.756

 

water

BS-5

same

56.645

-172.732

36

water

BS-6

same

59.320

-173.500

 

water

SLIP1

VNG1

62.013

-175.056

80

water, sediment

SLIP2

NWC5

62.051

-175.207

82

water, sediment

NBS

no

62.150

-175.400

78

Draft mooring site

SLIP3

NWC4

62.394

-174.570

73

water, sediment

SLIP5

VNG3.5

62.563

-173.556

65

water, sediment

SLIP4

NWC2.5

63.029

-173.457

72

water, sediment

UT-BS5

OK93-038

64.683

-169.099

47

water, sediment

UT-BS2

HX73-075

64.667

-169.922

45

water, sediment

UT-BS4

Laurier1999

64.959

-169.883

50

water, sediment

UT-BS1

HX59-120

64.992

-169.135

50

water, sediment

BRS5

HX171-69

65.652

-168.217

40

water

BRS4

HX171-70

65.668

-168.400

46

water

BRS3

HX171-71

65.682

-168.567

51

water

BRS2

HX171-72

65.700

-168.717

50

water

BRS1

HX171-73

65.717

-168.900

50

water

10 hr stop

Little Diomede Is.

 

 

 

site survey, offload

UTN-1

Stoker-172

66.709

-168.400

36

water, sediment

UTN-2

Laurier1998

67.051

-168.733

47

water, sediment

UTN-3

HX189-076

67.333

-168.998

52

water, sediment

UTN-4

HX74-010

67.501

-168.913

51

water, sediment

UTN-5

HX171-076

67.671

-168.958

54

water, sediment

UTN-6

AK47-055

67.736

-168.439

50

water, sediment

UTN-7

HX85-090

67.999

-168.933

60

water, sediment

 

2.  Quantitative benthic samples will be undertaken using the following equipment and sampling protocol:

a.     Five 0.1 m2 van Veen grabs at each station, with:

i.    The first grab will be used for surface sediment subsampling for:

·      chlorophyll-two surface sediment sample collected by syringe, and processed for fluorometric analyses shipboard

·      TOC/TON, C-13, grain size-subsamples collected, bagged, and frozen

·      HPLC pigment analyses-subsample collected, placed in vials, and frozen (DiTullio)

·      7-Beryllium-subsample collected and frozen for land-based analyses on gamma counter

 

ii.   The remaining 4 van Veen sediment collections will be sieved for faunal collections. Each van Veen sediment sample is placed in a 1 mm stainless steel screen box and sieved using regular seawater, the remaining animals subsequently preserved in 10% sea water formalin, buffered with hexamethylenetetramine, stored in plastic Whirl-pak bags, and saved for laboratory analyses back at the University of Tennessee.

 

b.  Three deployments of a single hole HAPS sediment corer (number of deployments depends on sediment conditions). The following methods are used for analyses:

 

i.    Two cores are used for sediment respiration experiments The two cores collected for shipboard incubation will be maintained in the dark at in situ bottom temperatures in the low temperature stand-up incubators for 10-12 hours.  Subsamples from the overlying water in these cores will be analyzed in the shipboard chambers for dissolved oxygen, , nutrients, denitrification, alkalinity, pH and total CO2. Subsequent to the end of the experiment, cores are sieved and fauna packaged and preserved with formalin for land-based identification.

ii.   One core for subsampling for vertical sediment parameters at the following intervals:

·      remaining sediments placed in 90 cc aluminum cans and frozen. Subsequent land-based analyses include TOC/TON, C-13, and grain size determinations.

 

NOTE: Both the van Veen grab and single Haps corer weigh about 150 lbs each and are easily deployed on a side-winch cable with a 50-60 m/min descent/assent rate.

 

D.  Mooring Deployment Near Slip 1 And Slip2

 

In summer 2003, we will deploy a subsurface mooring in 75-78 m of water near SLIP-1 and SLIP-2 in the northern Bering biological hot spot (Region A).  This mooring will consist of two seacats and ten microcats to measure profiles of temperature and salinity, two fluorometers to assess chlorophyll (phytoplankton biomass), two current meters and a nutrient meter (Table ).  In the second year, we will recover the first-year mooring and procure and deploy a second system to provide a multi-year continuous capability.  Table 1 provides the mooring deployment array.

 

E.  Site Survey At Little Diomede Island (10 Hrs)

 

During a 10 hr stop at Little Diomede Island, we will need assistance and use of a small boat from the Sir Wilfrid Laurier to transport equipment and personnel to the island and to undertake a site survey around the proposed outlet of the submerged seawater pipeline for the observatory. We have "key" measurements to make as part of our Bering Strait Observatory study that need to be measured at approximately 0800, 12 noon, and 1600 at Diomede Island for the pipeline site.


 

03STL-1A, July-03

 

Project:

St. Lawrence Is.

Location:

Bering Sea

Latitude:

 

Longitude:

 

Seafloor:

75 meters

Currents:

70 cm/s

 

 

Instruments:

 

Seacat

2

Micro cat

2

Nitrate Meter

1

RCM-9

2

SBE-39

8

release

1

 

 

Mooring:

 

Instrument

Depth

Seacat (FL/P)

11m

RCM-9-C

14m

SBE-39

17m

Nitrate Meter

18m

SBE-39

20m

SBE-39