Dataset: Eelgrass Shoot Density

Name: Eelgrass shoot density measurements taken during ecological field surveys along the eastern Pacific coast in June through August of 2019, 2020, and 2021.
Published: 2022-10-13
Keywords: seagrass wasting disease, Zostera marina, intertidal, eelgrass meadow, biota, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.879764.1

Spatial Extent: N:55.739951 E:-117.10621 S:32.62535 W:-133.343143

Temporal Extent: 2019-07-01 - 2021-07-28

Project:

Collaborative Research: The role of a keystone pathogen in the geographic and local-scale ecology of eelgrass decline in the eastern Pacific (Eelgrass disease)

Principal Investigator:

Drew Harvell (Cornell University, Cornell)

Co-Principal Investigator:

J. Emmett Duffy (Smithsonian Environmental Research Center, SERC)

Carla P. Gomes (Cornell University, Cornell)

Timothy Hawthorne (University of Central Florida, UCF)

John J. Stachowicz (University of California-Davis, UC Davis)

Scientist:

Lillian Aoki (Cornell University, Cornell)

Data Manager:

Lillian Aoki (University of Oregon)

BCO-DMO Data Manager:

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

Version:

Version Date:

2022-10-13

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Eelgrass shoot density measurements taken during ecological field surveys along the eastern Pacific coast in June through August of 2019, 2020, and 2021.

Abstract:

These data were collected during ecological field surveys of eelgrass (Zostera marina) meadows along the eastern Pacific from southeastern Alaska to southern California. Parameters measured include seagrass morphology, meadow condition (e.g. shoot densities), and incidence and severity of eelgrass wasting disease. Data were collected within the intertidal area of 32 eelgrass meadows distributed in six regions (five-six meadows sampled in the regions of Alaska, British Columbia, Washington, Oregon, California - Bodega Bay, and California - San Diego). Surveys were conducted in between late June and early August in 2019, 2020, and 2021 by teams from six institutions. The influence of disease on seagrass dynamics is not well understood, and these data can further understanding of the environmental drivers of disease by connecting wasting disease with eelgrass condition across a broad geographic gradient.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2022-10-13	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.879764.1	2022-10-21

Methods & Sampling

Field surveys of eelgrass meadow sites were conducted at mid-summer low tides at field sites along the west coast of North America in the U.S. and Canada. Samples and data were collected within the intertidal area of 32 eelgrass meadows distributed in six regions (Alaska, British Columbia, Washington, Oregon, California -Bodega Bay, and California -San Diego). Surveys were conducted between late June and early August in 2019, 2020, and 2021 by teams from six institutions.

For each site, three 20 meter transects were laid parallel to the shore at the shoreward (upper edge) of continuous eelgrass, and three lower (intertidal) 20 meter transects were laid at least 4 meters closer to the water. Shoot density and canopy cover were measured at meters 4, 8, 12, and 16. At each meter, a PVC quadrat was placed on the upper (landward) side of the transect tape, aligning the lower left corner of the quadrat with the meter mark. The percent cover within the quadrat area was recorded for seagrass, bare sediment, and other (macroalgae unless noted otherwise). Shoot densities, categorized by the number of vegetative and flowering shoots, were then counted. Only shoots rooted in the quadrat were included in the density counts. Quadrats for shoot density range in size from 0.0625 to 0.36 square meters. Quadrats for cover ranged in size from 0.09 to 1 square meter. Quadrat size was determined by expert judgment of the practitioners at each field site.

Transect locations were recorded using a hand-held GPS (exact model varied between field locations). Salinity was measured at the time of sampling using a refractometer. Temperature loggers (HOBO MX 2201 and UA-001-64, Onset, Bourne, MA) were deployed at each eelgrass meadow site to provide a continuous record of in situ temperature. For HOBO data, see https://www.bco-dmo.org/dataset/877355 and Related Datasets section below.

~ For methodology details, see Aoki et al. (2022)
~ Additional details for the field surveys are available in the Eelgrass Disease Project Handbook.
~ For 16S rRNA amplicon sequencing of eelgrass associated bacteria, refer to NCBI BioProject PRJNA802566 in the Related Datasets section below.

Data Processing Description

BCO-DMO Processing:
- Imported data from source file "meter_level_density.csv" into the BCO-DMO data system. Data file imported using missing data identifier "NA". Converted date to year-month-day format
- Imported data from source file "combined_site_metadata.csv". Converted coordinates to decimal degrees, made LocationNames consistent.
- Joined shoot metrics data with the revised combined site metadata
- Added conventional header with dataset name, PI name, version date.
- Modified parameter (column) names to conform with BCO-DMO naming conventions.

Parameters/Fields for Supplemental Files
(The following parameter descriptions are for the Supplemental File titled "Eelgrass study site metadata". For this dataset's fields, please see the heading "Parameters" below).

SampleCollectionDate: Date when samples were collected in the field
Region: Two-letter identifier for the geographic region where the sample was collected (AK=Alaska, BC=British Columbia, WA=Washington, OR=Oregon, BB=Bodega Bay in California, SD=San Diego in California)
SiteCode: One-letter identifier for site within a geographic region where the sample was collected (A, B, C, D, E, F)
LocationName: Full name of each sampling site (eelgrass meadow) where samples were taken
TidalHeight: Single letter indicating the tidal height at which samples were collected. U = upper tidal height; L = lower tidal height
Transect: Integer indicating the transect at which samples were collected. Upper transects = 1, 2, 3; Lower transects = 4, 5, 6.
SampleProcessingDate: Date when samples were processed in the lab
Depth: Depth relative to MLLW (mean lower low water)
Salinity: Salinity of surface water at the time of sampling (point measurement made with refractometer or probe)
LocationComments: Comments describing location including changes between sampling year
TransectBeginDecimalLatitude: Latitudinal coordinate for the beginning (meter 0) of the transect
TransectBeginDecimalLongitude: Longitudinal coordinate for the beginning (meter 0) of the transect
TransectEndDecimalLatitude: Latitudinal coordinate for the end (meter 20) of the transect
TransectEndDecimalLongitude: Longitudinal coordinate for the end (meter 20) of the transect
Year: Year in which samples were collected

Data Files

File
shoot_density.csv (Comma Separated Values (.csv), 299.11 KB) MD5:6ab64b348a29e8bf323f210216709604 Primary data file for dataset ID 879764

Supplemental Files

File

Eelgrass study site metadata
filename: eelgrass_study_revised_site_metadata.csv

(Comma Separated Values (.csv), 50.38 KB)
MD5:e17548ddde013aa9a344b97a16e3dfaf

Combined site metadata for eelgrass wasting disease study sites on the western coast of the U.S. and Canada

SampleCollectionDate:  Date when samples were collected in the field

Region: Two-letter identifier for the geographic region where the sample was collected (AK=Alaska, BC=British Columbia, WA=Washington, OR=Oregon, BB=Bodega Bay in California, SD=San Diego in California)

SiteCode: One-letter identifier for site within a geographic region where the sample was collected (A, B, C, D, E, F)

LocationName: Full name of each sampling site (eelgrass meadow) where samples were taken

TidalHeight: Single letter indicating the tidal height at which samples were collected.  U = upper tidal height; L = lower tidal height

Transect: Integer indicating the transect at which samples were collected.  Upper transects = 1, 2, 3; Lower transects = 4, 5, 6.

SampleProcessingDate: Date when samples were processed in the lab

Depth: Depth relative to MLLW (mean lower low water)

Salinity: Salinity of surface water at the time of sampling (point measurement made with refractometer or probe)

LocationComments: Comments describing location including changes between sampling year

TransectBeginDecimalLatitude: Latitudinal coordinate for the beginning (meter 0) of the transect

TransectBeginDecimalLongitude: Longitudinal coordinate for the beginning (meter 0) of the transect

TransectEndDecimalLatitude: Latitudinal coordinate for the end (meter 20) of the transect

TransectEndDecimalLongitude: Longitudinal coordinate for the end (meter 20) of the transect

Year: Year in which samples were collected

NSF Eelgrass Disease Project 2019 Handbook
filename: eelgrass_disease_project_handbook_v1.2.pdf

(Portable Document Format (.pdf), 1.38 MB)
MD5:f8f77aaf781cc5170a168012c938be31

NSF Eelgrass Disease Project 2019 Handbook v1.2 from MarineGEO

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1829890
NSF Division of Ocean Sciences	OCE-1829921
NSF Division of Ocean Sciences	OCE-1829922
NSF Division of Ocean Sciences	OCE-1829992

Deployments

None available yet

Instruments

Global Positioning System Receiver

Supplied Name: handheld GPS

Supplied Description:

Transect locations were recorded using a hand-held GPS (exact model varied between field locations).

Instrument Type

Generic Name: Global Positioning System Receiver

Acronym: GPS

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/POS03/

Generic Description:

The Global Positioning System (GPS) is a U.S. space-based radionavigation system that provides reliable positioning, navigation, and timing services to civilian users on a continuous worldwide basis. The U.S. Air Force develops, maintains, and operates the space and control segments of the NAVSTAR GPS transmitter system. Ships use a variety of receivers (e.g. Trimble and Ashtech) to interpret the GPS signal and determine accurate latitude and longitude.

Image scanner

Supplied Name: Epson Perfection V550 scanner

Supplied Description:

Cleaned eelgrass blades were imaged at high resolution (600 dpi) using an Epson Perfection V550 scanner.

Instrument Type

Generic Name: Image scanner

Acronym: scanner

Generic Description:

An electronic device that generates a digital representation of an image for data input to a computer.
OR a receiver designed to search for a signal within a specified frequency range. [Definition Source: NCI]

Onset HOBO Pendant MX2201 temperature logger

Supplied Name: HOBO MX2201 temperature logger

Supplied Description:

Instrument Type

Generic Name: Onset HOBO Pendant MX2201 temperature logger

Acronym: Onset HOBO Pendant MX2201

Generic Description:

The Onset HOBO MX2201 is an in-situ instrument for wet or underwater applications. It supports soil temperature, temperature, and water temperature. A one-channel logger that records up to approximately 96,000 measurements or internal logger events with 8K bytes memory. It has a polypropylene housing case. Uses Bluetooth to transmit data. Can be used with a solar radiation shield. Measurement range: -20 deg C to 70 deg C. Accuracy: +/- 0.50 deg C from 0 deg C to 50 deg C. Water depth rating: 30.5 m

Onset HOBO Pendant Temperature/Light Data Logger

Supplied Name: HOBO UA-001-064 temperature logger

Supplied Description:

Instrument Type

Generic Name: Onset HOBO Pendant Temperature/Light Data Logger

Acronym: Onset HOBO Pendant Temp/Light

Generic Description:

The Onset HOBO (model numbers UA-002-64 or UA-001-64) is an in-situ instrument for wet or underwater applications. It supports light intensity, soil temperature, temperature, and water temperature. A two-channel logger with 10-bit resolution can record up to approximately 28,000 combined temperature and light measurements with 64K bytes memory. It has a polypropylene housing case. Uses an optical USB to transmit data. A solar radiation shield is used for measurement in sunlight. Temperature measurement range: -20 deg C to 70 deg C (temperature). Light measurement range: 0 to 320,000 lux. Temperature accuracy: +/- 0.53 deg C from 0 deg C to 50 deg C. Light accuracy: Designed for measurement of relative light levels. Water depth rating: 30 m.

Refractometer

Supplied Name: refractometer

Supplied Description:

Salinity was measured at the time of sampling using a refractometer.

Instrument Type

Generic Name: Refractometer

Generic Description:

A refractometer is a laboratory or field device for the measurement of an index of refraction (refractometry). The index of refraction is calculated from Snell's law and can be calculated from the composition of the material using the Gladstone-Dale relation.

In optics the refractive index (or index of refraction) n of a substance (optical medium) is a dimensionless number that describes how light, or any other radiation, propagates through that medium.

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
Sample_Date	Date when samples were collected in the field Format: %Y-%m-%d	unitless	date
Sample_Id	Unique code identifying field samples based on the region, site, transect, tidal height, and sample replicate	unitless	sample
Region	Two-letter identifier for the geographic region where the sample was collected (AK=Alaska, BC=British Columbia, WA=Washington, OR=Oregon, BB=Bodega Bay in California, SD=San Diego in California)	unitless	region
Site_Code	One-letter identifier for the site within a geographic region where the sample was collected (A, B, C, D, E, F)	unitless	site
Location	Full name of each sampling site (eelgrass meadow) where samples were taken	unitless	site_descrip
Tidal_Height	Single letter indicating the tidal height at which samples were collected. U = upper tidal height; L = lower tidal height	unitless	tide
Depth	Depth relative to MLLW (mean lower low water)	meters (m)	depth
Salinity	Salinity of surface water at the time of sampling (point measurement made with refractometer or probe)	ppt	sal
Transect	Integer indicating the transect at which samples were collected. Upper transects = 1, 2, 3; Lower transects = 4, 5, 6.	unitless	transect
Meter	Exact meter along the transect where an individual sample was collected (m4, m8, m12, m16, m20)	unitless	transect_station
Density_Quadrat_Size	Size (area) of quadrat used to measure seagrass shoot densities in the field	square meters (m^2)	area_measured
Total_Shoots	Total count of seagrass shoots (flowering and non-flowering) counted in the quadrat	unitless	abundance
Flowering_Shoots	Number of flowering shoots within the quadrat	unitless	abundance
Cover_Quadrat_Size	Size (area) of quadrat used to measure seagrass and macroalgae cover in the field	square meters (m^2)	area_measured
Percent_Seagrass	Percent of quadrat area covered by seagrass canopy, from 0-1	unitless	percent_cover
Percent_Bare	Percent of quadrat area covered by bare sediment, from 0-1	unitless	percent_cover
Percent_Other	Percent of quadrat area covered by non-seagrass (e.g. macroalgae), from 0-1	unitless	percent_cover
Density_Shoots	Seagrass shoot density	shoots per square meter (shoots/m^2)	abundance
TransectBeginDecimalLatitude	Latitudinal coordinate for the beginning (meter 0) of the transect	decimal degrees	lat
TransectBeginDecimalLongitude	Longitudinal coordinate for the beginning (meter 0) of the transect	decimal degrees	lon
TransectEndDecimalLatitude	Latitudinal coordinate for the end (meter 20) of the transect	decimal degrees	lat
TransectEndDecimalLongitude	Longitudinal coordinate for the end (meter 20) of the transect	decimal degrees	lon
Notes	Comments from field and lab	unitless	comment

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Dataset: Eelgrass Shoot Density