Contributors | Affiliation | Role |
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Arrigo, Kevin R. | Stanford University | Principal Investigator |
Zehr, Jonathan P. | University of California-Santa Cruz (UCSC) | Co-Principal Investigator |
Mills, Matthew M. | Stanford University | Contact |
Biddle, Mathew | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Soenen, Karen | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
CTD sensor data from two cruises on which experiments were conducted. The experimental data related to this dataset can be found at BCO-DMO dataset UCYN-A Host activity (see related dataset).
Samples were collected using standard oceanographic techniques. A CTD Rosette with 24 10L Niskin bottles was lowered to the maximum sampling depth and then brought back to the surface. Data submitted from CTD is downcast data only.
BCO-DMO Processing Notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- removed duplicate depth columns
- removed duplicate sigma_theta columns
File |
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774459_v1_arrigo_ctd.csv (Comma Separated Values (.csv), 709.83 KB) MD5:c77e499d4702bec9477f68742684a02a Primary data file for dataset ID 774459, version 1 |
Parameter | Description | Units |
Cruise | cruise identifier | unitless |
Station | station identifier | unitless |
Cast | cast identifier | unitless |
Lat | latitude of observation. Positive values indicate North | decimal degrees |
Lon | longitude of observation. Positive values indicate East | decimal degrees |
Depth | depth of observation | meters (m) |
Press | pressure of observation | decibars (db) |
Temp1 | Water temperature from first sensor | degrees Celsius |
Temp2 | water temperature from second sensor | degrees Celsius |
Sal1 | salinity from first sensor | practical salinity units (PSU) |
Sal2 | salinity from second sensor | practical salinity units (PSU) |
O2 | oxygen from SBE 43 | mililiters per liter (ml/L) |
Fluor | fluorescence | miligrams per meter cubed (mg/m3) |
Par | Photosythetically active radiation (PAR) | percent |
SigTheta1 | sigma-theta density from first sensor | kilograms per meter cubed (kg/m3) |
SigTheta2 | sigma-theta density from second sensor | kilograms per meter cubed (kg/m3) |
Time_elapsed | time elapsed | seconds (s) |
Depth_bot | bottom depth | meters (m) |
Density | density sigma-theta | kilograms per meter cubed (kg/m3) |
Pot_temp1 | Potential temperature sensor 1 | degrees Celsius |
Pot_temp2 | Potentia temperature sensor 2 | degrees Celsius |
Dataset-specific Instrument Name | CTD Rosette |
Generic Instrument Name | CTD - profiler |
Dataset-specific Description | A CTD Rosette with 24 10L Niskin bottles was lowered to the maximum sampling depth and then brought back to the surface. |
Generic Instrument Description | The Conductivity, Temperature, Depth (CTD) unit is an integrated instrument package designed to measure the conductivity, temperature, and pressure (depth) of the water column. The instrument is lowered via cable through the water column. It permits scientists to observe the physical properties in real-time via a conducting cable, which is typically connected to a CTD to a deck unit and computer on a ship. The CTD is often configured with additional optional sensors including fluorometers, transmissometers and/or radiometers. It is often combined with a Rosette of water sampling bottles (e.g. Niskin, GO-FLO) for collecting discrete water samples during the cast.
This term applies to profiling CTDs. For fixed CTDs, see https://www.bco-dmo.org/instrument/869934. |
Website | |
Platform | R/V Robert Gordon Sproul |
Start Date | 2017-05-03 |
End Date | 2017-05-11 |
Description | R/V Robert Gordon Sproul
Cruise SP1714
May 3 - 11, 2017
Chief Scientist - Matthew Mills (mmmills@stanford.edu)
See more cruise information from R2R: https://www.rvdata.us/search/cruise/SP1714 |
Website | |
Platform | R/V Robert Gordon Sproul |
Start Date | 2017-10-04 |
End Date | 2017-10-11 |
Description | R/V Robert Gordon Sproul
Cruises SP1727
October 4 - 11, 2017
Chief Scientist - Matthew Mills (mmmills@stanford.edu)
See more cruise information from R2R: https://www.rvdata.us/search/cruise/SP1727 |
NSF Award Abstract:
Nitrogen is a nutrient whose availability limits growth and productivity of ecosystems. Nitrogen is extremely abundant in the atmosphere in the inert form of gaseous N2, but most organisms cannot reduce N2 into a biologically available form. In all environments, including agricultural soils, there are microorganisms that can make available the N from gaseous N2 by reducing it to the biologically available form, ammonium. In the vast expanses of the open ocean, few organisms are known to have this ability, and recently a unique symbiosis between a single-celled cyanobacterium and a single-celled algae was discovered, which appears to be very widely distributed and likely of global biogeochemical significance. The cyanobacterium in this symbiotic partnership has very unusual metabolism and genomic streamlining. Little is known of the symbiosis because it is not detectable except by modern molecular biological techniques. Recent work has shown this symbiosis to be very widely spread through the oceans, and that there is previously unrecognized diversity in both the cyanobacterial and algal hosts. This research will examine the environmental distributions and the biogeochemical significance of this diversity in coastal US waters. The investigators will engage the public in ocean sciences through internship programs at local high schools and for undergraduate students at Stanford, and by documenting their field research in a 'virtual cruise' blog.
In the marine environment, the contribution of N2 fixation to the fixed nitrogen (N) pool is poorly quantified, in part due to an incomplete understanding on the abundance, activity, and physiology of diazotrophs. The symbiotic unicellular cyanobacteria (UCYN-A) is a poorly characterized, yet globally important, group of marine diazotrophs. UCYN-A is widely distributed in the marine environment, and lives symbiotically with a picoeukaryotic prymnesiophyte alga. We now know that there are multiple ecotypes of UCYN-A, which may be adapted to specific locations in the water-column and different oceanic provinces. Typically N2 fixation was considered unimportant in coastally influenced and non-tropical waters, however recent data shows that multiple subclades of UCYN-A are present. The distribution and rate of N2 fixation by UCYN-A subclades in coastal/nearshore environments is a major unknown in the oceanic N cycle. Its presence in nearshore waters may change the paradigm of the balance between basin N sources (N2 fixation) and sinks (denitrification). Likewise, significant N2 fixation by UCYN-A will need to be considered when determining estimates of new production in coastally influenced waters. This project aims to quantify the significance of different UCYN-A subclades to coastal/nearshore N budgets. It tackles the issue of determining N2 fixation rates by different UCYN-A subclades in coastal waters through rigorous fieldwork off the west coast of North America. The temporal and spatial distribution of UCYN-A subclades, as well as the rates of N2 fixation, will be determined by coupling N2 fixation measurements of bulk communities and individual cells (nanoSIMS) with molecular assays to study these widespread, but dilute, diazotrophic symbionts and their hosts. Additionally the investigators will conduct experiments aimed at constraining the effects of light and nutrient ratios (N/P) on UCYN-A N2 fixation rates, and the prymnesiophyte host's rate of carbon fixation. They will conduct this work through seasonal sampling of a coastal site in the Southern California Bight (Scripps Pier) and on two process cruises in the coastal waters between central California and the Baja Peninsula. The cruise work will provide an opportunity to understand the temporal dynamics of the UCYN-A/prymnesiophyte associations over larger spatial scales. Finally, evidence suggests that unidentified UCYN-A subclades and hosts exist and the investigators have developed a strategy to identify and quantify their temporal and spatial distributions as well as their N2 fixation activities. Data on the coastal distribution, ecology and activity of UCYN-A is critical for obtaining a better understanding of their contribution to fixed N to the marine environment. The group-specific and bulk rates of N2 fixation measured in this study of coastally influenced waters, will provide data for future modeling efforts, which will make an important contribution to constraining oceanic N2 fixation inputs.
Funding Source | Award |
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NSF Division of Ocean Sciences (NSF OCE) | |
NSF Division of Ocean Sciences (NSF OCE) |