Experimental and biogeochemical surveys from R/V Kilo Moana, R/V Knorr, and R/V Ka`imikai-O-Kanaloa cruises in the North Pacific Subtropical Gyre and Hawaiian Islands: stations Kahe, ALOHA, Kena and WHOTS Mooring from 2008 to 2009

Website: https://www.bco-dmo.org/dataset/3883
Version: 01 March 2013
Version Date: 2013-03-01

Project
» Silica Cycling and the Role of Diatoms in the North Pacific Subtropical Gyre (Silica Cycling)
ContributorsAffiliationRole
Brzezinski, Mark A.University of California-Santa Barbara (UCSB)Principal Investigator, Contact
Villareal, Tracy A.University of Texas at Austin (UT Austin)Co-Principal Investigator
Jones, Janice L.University of California-Santa Barbara (UCSB-LifeSci)Technician
Gegg, Stephen R.Woods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager


Dataset Description

BioGeoChem - Experimental and Survey Biogeochemical Data

BCO-DMO Note 1: The chlorophyll data belong to Tracy Villareal.
Information on his method was not provided.

BCO-DMO Note 2: These data are VERY preliminary.
They will be reviewed after March 30th.
srg/01March2013


Acquisition Description

Links to Protocols Documentation:
32Si_HOT_Protocol - 32Si Sample Processing - HOT Cruises
32Si _Protocol - 32Si Production Protocol - POOB Cruises
delta_bSi_HOT_Protocol - delta bSi Production Protocol - HOT Cruises
delta_bSi_Protocol - delta bSi Production Protocol - POOB Cruises
dSi_Protocol - Dissolved Si Analysis
HOT_Sample_Collection - HOT Sample Collection
pSi_Protocol - Particulate Si Analysis


Processing Description

BCO-DMO Processing/Edits
- Generated from original file: "POOB_ALLDATA.xlsx" contributed by Janice Jones
  Sheets: "POOB08", "POOB2009" and "HOT"

- BCO-DMO compatible parameter header generated
  Spaces converted to underscores
  Units removed from variable names
  Special characters removed/replaced

- Date reformatted to YYYYMMDD
- Time reformatted to HHMM
- "~" converted to "nd"
- blank cells converted to "nd"


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Parameters

ParameterDescriptionUnits
Cruisecruise during which sample was collected text
Stationsampling station dimensionless
Ctype of sample (for ODV use only - currently set to C) C
Datelocal date YYYYMMDD
Timelocal time HHMM
Latlatitude in decimal degrees (South is negative) decimal degrees
Lonlongitude in decimal degrees (West is negative) decimal degrees
Bot_Depthbottom depth in meters meters
Event_Numberevent number as yyjulhhh using Julian Day and GMT OR HOT event number as per HOT protocol yyjulhhhh GMT
Station_Numberstation number dimensionless
CastCTD cast number dimensionless
Cast_Typecast type (CTD or sediment trap) dimensionless
Target_Depthtarget bottle tripping depth in meters meters
Actual_Depthactual bottle tripping depth in meters meters
Rosette_Bottlerosette bottle number dimensionless
Percent_lopercent light level (PAR sensor) percentage
SiOH4silicic acid concentration in micromoles (also known as dissolved silicon concentration or dSi) uM
bSi_0point6umparticulate biogenic silica in >0.6um fraction in nanomoles Si per litre nmol Si/L
bSi_10umparticulate biogenic silica in >10um fraction in nanomoles Si per litre nmol Si/L
Lsi_0point6umparticulate lithogenic silica in >0.6um fraction in nanomoles Si per litre nmol Si/L
Chl_a_0point4umchlorophyll a in >0.4um fraction in micrograms per litre *** DATA BELONGS TO TRACY VILLAREAL ug/L
Chl_a_10umchlorophyll a in >10um fraction in micrograms per litre *** DATA BELONGS TO TRACY VILLAREAL ug/L
Si32_rhogross silica production rate umol Si/L/d
Si32_Vbspecific silica production rate (gross normalized to biogenic silica concentration) d-1
delta_bSi_rhonet silica production rate nmol Si/L/d
rho_dissolutiongross silica dissolution rate nmol Si/L/d
V_dissolutionspecific silica dissolution rate (gross normalized to biogenic silica concentration) d-1


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Instruments

Dataset-specific Instrument Name
Niskin bottle
Generic Instrument Name
Niskin bottle
Generic Instrument Description
A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc.

Dataset-specific Instrument Name
CTD Sea-Bird SBE 911plus
Generic Instrument Name
CTD Sea-Bird SBE 911plus
Dataset-specific Description
CTD Sea-Bird SBE 911plus
Generic Instrument Description
The Sea-Bird SBE 911plus is a type of CTD instrument package for continuous measurement of conductivity, temperature and pressure. The SBE 911plus includes the SBE 9plus Underwater Unit and the SBE 11plus Deck Unit (for real-time readout using conductive wire) for deployment from a vessel. The combination of the SBE 9plus and SBE 11plus is called a SBE 911plus. The SBE 9plus uses Sea-Bird's standard modular temperature and conductivity sensors (SBE 3plus and SBE 4). The SBE 9plus CTD can be configured with up to eight auxiliary sensors to measure other parameters including dissolved oxygen, pH, turbidity, fluorescence, light (PAR), light transmission, etc.). more information from Sea-Bird Electronics


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Deployments

KM0812

Website
Platform
R/V Kilo Moana
Start Date
2008-07-01
End Date
2008-07-22
Description
This cruise was funded by NSF award OCE-0648130. Original cruise data are available from the NSF R2R data catalog. Note that the cruise dates were determined from the information reported in the UNOLS STRS system and the R2R catalog.

KM0919

Website
Platform
R/V Kilo Moana
Start Date
2009-07-29
End Date
2009-08-14
Description
This cruise was funded by NSF OCE-0648130. Original cruise data are available from the NSF R2R data catalog.

KM0801

Website
Platform
R/V Kilo Moana
Report
Start Date
2008-01-28
End Date
2008-02-01
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0802

Website
Platform
R/V Kilo Moana
Report
Start Date
2008-02-22
End Date
2008-02-26
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0806

Website
Platform
R/V Kilo Moana
Report
Start Date
2008-05-26
End Date
2008-05-30
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0811

Website
Platform
R/V Kilo Moana
Report
Start Date
2008-06-24
End Date
2008-06-28
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0813

Website
Platform
R/V Kilo Moana
Report
Start Date
2008-07-25
End Date
2008-07-29
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0815

Website
Platform
R/V Kilo Moana
Report
Start Date
2008-08-15
End Date
2008-08-19
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0820

Website
Platform
R/V Kilo Moana
Report
Start Date
2008-10-09
End Date
2008-10-13
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0822

Website
Platform
R/V Kilo Moana
Report
Start Date
2008-11-29
End Date
2008-12-03
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0902

Website
Platform
R/V Kilo Moana
Report
Start Date
2009-01-19
End Date
2009-01-23
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0907

Website
Platform
R/V Kilo Moana
Report
Start Date
2009-02-16
End Date
2009-02-20
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KN195-07

Website
Platform
R/V Knorr
Report
Start Date
2009-04-27
End Date
2009-05-01
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets

KOK0909

Website
Platform
R/V Ka`imikai-O-Kanaloa
Report
Start Date
2009-05-26
End Date
2009-05-30
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0915

Website
Platform
R/V Kilo Moana
Report
Start Date
2009-07-02
End Date
2009-07-06
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0918

Website
Platform
R/V Kilo Moana
Report
Start Date
2009-07-23
End Date
2009-07-27
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KM0920

Website
Platform
R/V Kilo Moana
Report
Start Date
2009-08-17
End Date
2009-08-21
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KOK0916

Website
Platform
R/V Ka`imikai-O-Kanaloa
Report
Start Date
2009-09-23
End Date
2009-09-27
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KOK0917

Website
Platform
R/V Ka`imikai-O-Kanaloa
Report
Start Date
2009-11-02
End Date
2009-11-06
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.

KOK0920

Website
Platform
R/V Ka`imikai-O-Kanaloa
Report
Start Date
2009-12-08
End Date
2009-12-12
Description
HOT - Cruise Schedules, Chief Scientist Reports and Cast Sheets Cruise information and original data are available from the NSF R2R data catalog.


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Project Information

Silica Cycling and the Role of Diatoms in the North Pacific Subtropical Gyre (Silica Cycling)

Coverage: North Pacific Subtropical Gyre north of Hawaii, near (30 N, 140 W)


This study examines the unique silicon cycle of the North Pacific Subtropical Gyre (NPSG).

Most marine silicon cycle studies have focused on the more productive coastal waters or the Southern Ocean where diatoms typically dominate the phytoplankton. Although diatom biomass is much lower in subtropical gyres, silica production is significant in global terms. Silicon cycle studies of the Sargasso Sea in the 1990’s implied that subtropical gyres account for 13% of global marine silica production. More recent data from the NPSG show much higher rates of silica production that would increase the contribution of subtropical gyres to as much as 40%. The new estimate is uncertain and based on few data, but suggests that the contribution of subtropical gyres has been underestimated. Differences in the silicon cycle between the NPSG and the Sargasso Sea go beyond differences in average production rates. The two systems are several months out of phase with each other in terms of their seasonal silica production cycles. Unlike the Sargasso Sea, where diatoms bloom regularly in spring in response to winter convective overturn, permanent stratification prevents spring diatom blooms events in the NPSG, where annual diatom blooms occur in summer, when stratification is strongest and nutrient concentrations are at a seasonal minimum. These enigmatic summer blooms contribute significantly to carbon and nitrogen export in the NPSG and likely dominate the annual silicon cycle.

Time series of rate measurements will be made in collaboration with the HOT program to define the annual silicon cycle at station ALOHA. The project will also collaborate with the new "Center for Microbial Oceanography: Research and Education" (CMORE) Science and Technology Center at the University of Hawaii to study summer blooms. Funding for this portion of the project is from NSF OCE-0648130.

Separately funded laboratory studies (NSF OCE-0726726; Title: Biological characterization of the nitrogen-fixing Rhizosolenia-Richelia symbiosis), looked at the role of diatom-diazotroph associations (DDAs) in elemental cycling in the NPSG.

Nitrogen-fixation provides a key input of new nitrogen into oligotrophic, oceanic regions. Work over the past two decades has highlighted the role of Trichodesmium. More recently, the role of coccoid cyanobacteria as well as symbiotic associations of the filamentous cyanobacteria Richelia intracellularis with species of diatoms (Rhizosolenia and Hemiaulus) has received attention. Little is known of the growth rates, nutrient needs, chemical composition, or environmental tolerances of these DDAs. However, it is clear that DDAs are numerically important in some oceans and can play a major role in mediating new nitrogen inputs. Recent models have identified the need for species-specific parameters, but these are lacking for DDAs. In particular, temperature dependent properties require quantification for application to global warming scenarios.

Laboratory studies of both the Rhizosolenia-Richelia and Hemiaulus-Richelia DDA are now possible due to the reproducible cultivation of this association. This four-year research program will quantify temperature and salinity effects on growth rates and NB2B-fixation rates. It will explore the role of silicate and phosphate (inorganic and organic) in controlling growth rates, chemical composition and NB2B-fixation through host-symbiont interactions. Field studies will address the distribution of both these DDAs and their contribution to Si cycling in large diatom blooms reported from the central N. Pacific gyre.

The mass accumulation of the DDAs in sediment traps as well as in the sedimentary record suggest DDAs are important vectors to depth. The potentially high sinking rates relative to Trichodesmium permit rapid export of new N and sequestration of C. This work will quantify settling rates under conditions of phosphate and silicate-limited growth and provide the first estimates of potential losses due to sinking. This program will provide the first broad characterization of a DDA and provide valuable input data for models.

DDA blooms are potential means to remove C and N quickly from the euphotic zone via mass sedimentation of the diatom host. Diatom remains in sediments suggest this is an important vector for sedimentary deposition. The auteocological work in this study will produce information important for interpreting how such events can occur. In addition, temperature tolerance studies will yield data useful for understanding how this DDA could respond to warming oceans.

The proposed research on Si cycling combined with ongoing studies of C, N and P cycling at station ALOHA will allow, for the first time, an opportunity for a coordinated analysis the cycling of all four of these elements simultaneously in an oligotrophic gyre. The pairing of field work with laboratory studies to determine the role of DDAs will expand understanding of the mechanisms controlling the contribution of diatoms to elemental cycling in open ocean ecosystems.

RELATED PUBLICATIONS

Brzezinski MA, Krause JW, Church MJ, Karl DM, Li B, Jones JL, Updyke B. "The annual silica cycle of the North Pacific subtropical gyre," Deep Sea Research I, v.58, 2011, p. 998.

Duhamel S., Bjorkman K. M., Van Wambeke F., Moutin T., Karl DM. "Characterization of alkaline phosphatase activity in the North and South Pacific Subtropical Gyres: Implications for phosphorus cycling," Limnology and Oceanography, v.56, 2011, p. 1244.

Krause J.W., Brzezinski M.A., Jones J.L. "Application of low-level beta counting of 32Si for the measurement of silica production rates in aquatic environments," Marine Chemistry, v.127, 2011, p. 40.

Krause J.W., Brzezinski M.A., Villareal, T.A., Wilson C. "Increased kinetic efficiency for silicic acid uptake as a driver of summer diatom blooms in the North Pacific subtropical gyre," Limnology and Oceanography, v.57, 2012, p. 1084.

Villareal, T.A.; Adornato, L.; Wilson, C.; Shoenbachler, C.A. "Summer blooms of diatom-diazotroph assemblages (DDAs) and surface chlorophyll in the N. Pacific gyre - a disconnect" Journal of Geophysical Research-Oceans, v.116, 2011, p. DOI: 10.1.

Villareal T.A., Brown, C. G., Brzezinski M.A., Krause J.W., Wilson C.. "Summer Diatom Blooms in the North Pacific Subtropical Gyre: 2008-2009," PLos ONE, v.7, 2012, p. e33109.

Watkins-Brandt K.S., Letelier R.M., Spitz Y.H., Church M.J., Bottjer D., White Angelicque. "Addition of inorganic or organic phosphorus enhances nitrogen and carbon fixation in the oligotrophic North Pacific," Marine Ecology Progress Series, v.432, 2011, p. 17.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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