Dataset: BATS primary production

Name: Primary production determinations at the Bermuda Atlantic Time-series Study site (BATS) from 1988-2022
Published: 2023-04-18
Keywords: primary productivity, BATS, incubations, radioactive tracer, biota, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.893182.1

Spatial Extent: N:32.108 E:-64.012 S:30.729 W:-65.168

Temporal Extent: 1988-12-18 - 2022-12-16

Project:

Bermuda Atlantic Time-series Study (BATS)

Program:

Ocean Carbon and Biogeochemistry (OCB)

U.S. Joint Global Ocean Flux Study (U.S. JGOFS)

Ocean Time-series Sites (Ocean Time-series)

Principal Investigator:

Nicholas Bates (Bermuda Institute of Ocean Sciences, BIOS)

Co-Principal Investigator:

Rodney J. Johnson (Bermuda Institute of Ocean Sciences, BIOS)

Scientist:

Paul J. Lethaby (Bermuda Institute of Ocean Sciences, BIOS)

BCO-DMO Data Manager:

Dana Stuart Gerlach (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2023-04-18

Restricted:

Validated:

Yes

Current State:

Final with updates expected

Primary production determinations at the Bermuda Atlantic Time-series Study site (BATS) from 1988-2022

Abstract:

Data presented are primary production estimates at the Bermuda Atlantic Time-series Study (BATS) site in the Sargasso Sea from December 1988 (BATS Cruise 3) through December 2022 (BATS cruise 399). The rate of carbon fixation by autotrophs in seawater was determined by tracing the uptake of radioactive 14C from the inorganic form to the particulate organic form. Incubations were performed in situ at depths ranging from the surface to 140 meters from dusk to dawn. Seawater samples were collected prior to sunrise, separated into three light bottles and one dark bottle, and a radioactive 14C tracer added. The bottles were then deployed on an incubation array at their collection depths, and allowed to drift on the array for the full light day. Samples were recovered after sunset and filtered for subsequent analysis on a liquid scintillation counter.

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2023-04-18	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.893182.1	2023-04-18

Methods & Sampling

Primary production is measured in situ as part of the monthly Bermuda Atlantic Time Series (BATS) cruises.

Scope and field of application
Primary production is a fundamental ecological variable for understanding the flow of energy into an ecosystem as it supports the availability of organic material as building blocks for higher trophic levels. This method uses a radiocarbon ¹⁴C spike and liquid scintillation counter (LSC) techniques to quantify the rate of primary production. This procedure describes the method for the determination of primary production in seawater, expressed as milligrams of carbon per cubic meter per day (mg C m⁻³day⁻¹) . This method is suitable for the assay of all levels of primary production found in the ocean.

Primary production is defined as the rate of uptake of inorganic carbon (DIC) into particulate organic carbon (POC),

DIC_n * POC¹⁴C * 1.05
C uptake = ----------------------------- , where
DIC¹⁴C

C uptake = rate of carbon fixation (mg Carbon m⁻³day⁻¹)
DIC_n = naturally occurring dissolved inorganic carbon
POC¹⁴C = ¹⁴C spiked particulate organic carbon
DIC¹⁴C = ¹⁴C spiked dissolved inorganic carbon
1.05 = metabolic discrimination factor due to biological isotopic fractionation (preferable uptake of lighter isotopes)

Principle of analysis
The rate of carbon fixation by autotrophs in seawater is measured by tracing the uptake of radioactive ¹⁴C from the inorganic form to the particulate organic form. Radiocarbon is added at an assumed ratio to the total inorganic carbon content of the seawater sample. The uptake of radiocarbon by the particulate phytoplankton is converted to total carbon uptake by the application of this radiocarbon: total carbon ratio. Inorganic carbon is not measured because samples are acidified before analysis. The seawater is collected using the CTD at discrete depths every 20 meters from the surface to 140 meters. The radioactive ¹⁴C spike is added and samples are incubated in situ at their respective depths using a free-floating array. The array is deployed prior to first light and recovered after sunset to capture the dawn to dusk light cycle.

A liquid scintillation counter (LSC) is used to calculate the level of radioactivity in the sample and therefore the amount of ¹⁴C particulate organic carbon. The LSC measures the conversion of radioactive decay events into photons of light, which are detected by photomultiplier tubes and converted into electrical pulses. In order to aid the detection of radioactivity, a liquid scintillation cocktail is added (Ultima gold for this method). The cocktail contains both solvent and scintillator molecules. The radioactive decay from the ¹⁴C excites the solvent molecule, and the energy is transferred to the scintillator which re-emits the energy in the form of light. Often more than one type of scintillator is present in the cocktail to allow for the emission of light at a suitable wavelength to be detected by the photomultiplier tubes. The resulting electrical signal that is generated is recorded as counts per minute (CPM).

Field sampling

Samples for primary production are collected two hours before dawn (pre-dawn production cast) and no other samples are taken during this cast. Nitrile gloves are used during the handling of samples. The polycarbonate incubation bottles are filled directly from the Niskins under low light conditions. Each bottle is rinsed 3 times before filling. Five bottles are filled for each sample depth. 250 µl of the ¹⁴C working solution is added to each of the five bottles in the shared use radioisotope lab container. Low light levels are maintained by using red lights in the lab. One of the five bottles is wrapped in electrical tape; this bottle is then wrapped in aluminium foil to ensure it is kept in dark conditions. One of the five productivity bottles is used as the time-zero (T-0) sample. The spike is added, the sample is then thoroughly shaken before 50 ml is filtered. A 250 µl aliquot -- to be used for counting total added ¹⁴C activity -- is removed from each of the T-0 bottles and is placed in a 20 ml glass scintillation vial containing 250 µl ethanolamine.

Approximately one hour before sunrise the productivity array is deployed. The incubation occurs throughout the day and the array is recovered approximately half an hour after sunset. Upon recovery and under low light conditions, a 50 ml aliquot is withdrawn from each productivity bottle and filtered onto a 25 mm Whatman® Glass Fibre Filter, maintaining vacuum levels of 70 mm Hg or less. Neither the filter nor the syringe is rinsed. The filter is placed into a 20 ml glass scintillation vial. Under a fume hood, excess radioactive carbon is driven off by adding 250 µl 0.5 N hydrochloric acid. A 250 µl aliquot for counting total added ¹⁴C activity (Time End Specific Activity) is removed from one of the light productivity bottles. This is placed in a 20 ml glass scintillation vial containing 250 µl ethanolamine (Sigma), similar to the T-0 described in Time Zero Specific Activity Sample. The samples are then stored at room temperature until analysis.

For additional details, please see Protocols for the Bermuda Atlantic Time-series Study Core Measurements.

Data Processing Description

BCO-DMO Processing Notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- converted latitude and longitude to decimal degrees
- added columns for Cruise_type, Cruise_num, Cast_type, Cast, and Bottle_number based on the ID column info
- added column for ISO date
- missing data identifier of -999 maintained as per PI request

Data Files

File
bats_primary_production.csv (Comma Separated Values (.csv), 590.90 KB) MD5:c0279727bc94f8539fe5c0390605d0b2 BATS primary production

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-0752366
NSF Division of Ocean Sciences	OCE-1756105

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
BATS_cruises	Bermuda Atlantic Time-series Study cruises	1988-10-20	Unknown Platform	Nicholas Bates (Principal Investigator) Michael W. Lomas (Co-Principal Investigator) Rodney J. Johnson (Scientist) Theresa McKee (BCO-DMO Data Manager)	data info

Instruments

Light-Dark Bottle

Supplied Name: light and dark incubation bottles

Supplied Description:

Seawater samples were collected prior to sunrise, separated into three light bottles and one dark bottle, and a radioactive 14C tracer added. The bottles were then deployed on an incubation array at their collection depths, and allowed to drift on the array for the full light day.

Instrument Type

Generic Name: Light-Dark Bottle

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/82/

Generic Description:

The light/dark bottle is a way of measuring primary production by comparing before and after concentrations of dissolved oxygen.

Bottles containing seawater samples with phytoplankton are incubated for a predetermined period of time under light and dark conditions. Incubation is preferably carried out in situ, at the depth from which the samples were collected. Alternatively, the light and dark bottles are incubated in a water trough on deck, and neutral density filters are used to approximate the light conditions at the collection depth.

Rates of net and gross photosynthesis and respiration can be determined from measurements of dissolved oxygen concentration in the sample bottles.

Liquid Scintillation Counter

Supplied Description:

A Liquid Scintillation Counter is used to calculate the level of radioactivity in the sample and therefore the amount of 14C particulate organic carbon

Instrument Type

Generic Name: Liquid Scintillation Counter

Acronym: LSC

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB21/

Generic Description:

Liquid scintillation counting is an analytical technique which is defined by the incorporation of the radiolabeled analyte into uniform distribution with a liquid chemical medium capable of converting the kinetic energy of nuclear emissions into light energy. Although the liquid scintillation counter is a sophisticated laboratory counting system used the quantify the activity of particulate emitting (ß and a) radioactive samples, it can also detect the auger electrons emitted from 51Cr and 125I samples.

Niskin bottle

Supplied Description:

Instrument Type

Generic Name: Niskin bottle

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/

Generic 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.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
Cruise_type	Cruise type (BATS Core, Bloom A, or Bloom B)	unitless	cruise_type
Cruise_num	Cruise number	unitless	cruise_id
Cast_type	Cast type (CTD or Hydrocast)	unitless	cast_type
Cast	Cast Number (1-80 = CTD, 81-99 = Hydrocast)	unitless	cast
Bottle_number	Niskin bottle number	unitless	bot_Nis
Date	Date of collection Format: %Y-%m-%d	unitless	date
ID	Sample identification; a unique number which identifies cruise, cast, and bottle number	unitless	sample
decy_in	Deployment date in decimal year	decimal year	year_decimal
decy_out	Recovery date in decimal year	decimal year	year_decimal
Latitude_in	Latitude of deployment (and initial pre-dawn water collection)	decimal degrees	lat
Latitude_out	Latitude of recovery	decimal degrees	lat
Longitude_In	Longitude of deployment (and initial pre-dawn water collection)	decimal degrees	lon
Longitude_Out	Longitude of recovery	decimal degrees	lon
QF	Niskin bottle Quality Flag (-2 = misfire, 0= no data, 1 = unverified, 2= verified acceptable, 5= no CTD data)	unitless	q_flag
dep1	Collection depth in meters	meters (m)	depth
pres	Pressure as measured by CTD	decibars (dbar)	press
temp	CTD temperature	degrees Celsius	temp
salt	Salinity from GoFlo bottle or CTD	unitless	sal
lt1	14C Primary Production light bottle #1	milligrams C per cubic meter per day (mgC/m^3/day )	PP
lt2	14C Primary Production light bottle #2	milligrams C per cubic meter per day (mgC/m^3/day )	PP
lt3	14C Primary Production light bottle #3	milligrams C per cubic meter per day (mgC/m^3/day )	PP
dark	14C Primary Production dark bottle	milligrams C per cubic meter per day (mgC/m^3/day )	PP
t0	14C Primary Production Time zero	milligrams C per cubic meter per day (mgC/m^3/day )	PP
pp	Primary production mean of light values minus dark value	milligrams C per cubic meter per day (mgC/m^3/day )	PP
yymmdd_in	Year Month Day of deployment	unitless	start_date
yymmdd_out	Year Month Day of recovery	unitless	end_date
hhmm_in	Time of deployment	unitless	time
hhmm_out	Time of recovery	unitless	time

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Dataset: BATS primary production