Dataset: St John Octocoral Abundances 2019

Name: Octocoral colony heights measured during transect surveys at four sites on the south shore of St. John, US Virgin Islands during June-October 2019
Published: 2020-02-12
Keywords: oceans

Cite This Dataset

DOI:10.1575/1912/bco-dmo.793259.1

Spatial Extent: N:18.3167 E:-64.7104 S:18.3029 W:-64.7299

Temporal Extent: 2019-07-10 - 2019-10-03

Project:

Collaborative Research: Pattern and process in the abundance and recruitment of Caribbean octocorals (Octocoral Community Dynamics)

Principal Investigator:

Howard Lasker (State University of New York at Buffalo, SUNY Buffalo)

Co-Principal Investigator:

Peter J. Edmunds (California State University Northridge, CSUN)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2020-02-12

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Octocoral colony heights measured during transect surveys at four sites on the south shore of St. John, US Virgin Islands during June-October 2019

Abstract:

This dataset contains octocoral colony heights measured during transect surveys at four sites on the south shore of St. John, US Virgin Islands in June-October 2019. These data are a continuation of BCO-DMO project 562086 (http://www.bco-dmo.org/project/562086) and BCO-DMO project 749653 (https://www.bco-dmo.org/project/749653).

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2020-02-12	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.1575/1912/bco-dmo.793259.1	2020-02-24

Description

This dataset contains octocoral colony heights measured during transect surveys at four sites on the south shore of St. John, US Virgin Islands in June-October 2019.

These data are a continuation of BCO-DMO project 562086 (http://www.bco-dmo.org/project/562086) and BCO-DMO project 749653 (https://www.bco-dmo.org/project/749653).

Methods & Sampling

Survey design:
All sites were located at 6 to 9 meters depth.

Censuses at East Cabritte, Europa, and Tektite were based on 50x10m areas that were arbitrarily selected and permanently marked with stainless steel eyebolts at the corners of the sites. A total of six transect lines, also marked with eyebolts, were laid out at 10 m intervals. All octocorals present in 1 x 1 m quadrats along the 10-meter long transects were scored. The transect identifier "transect_pos" has values 0, 10, 20, 30, 40 or 50 which represent position in meters within the 50x10 survey area corresponding to each of the 6 transects (e.g. 20 = 20m).

The census at Booby Rock was conducted in a single day in which transects were randomly placed along a 50 m line that was arbitrarily placed on a constant depth contour. The transect identifier (transect_pos) for transects at Booby Rock refers to position along the 50 m line.

Yawzi and Deep Tektite surveys: 20 quadrats at each transect (3 transects). Yawzi transects were censused over two field trips, July/August and September.

Sampling methods:
Identifications were based on traits visible in the field, and samples of representative colonies were collected for further analysis in cases in which field identification was uncertain. Sclerites from those samples were examined for species identification.

Two height measures are present, height of living tissue, which only includes that part of the axis with living tissue and total height which is the distance from the base to the tip of the farthest branch from the base (i.e. not necessarily perpendicular to the substrate), regardless of whether the tips or base had living tissue. (Only colonies with some living tissue were measured). All measures rounded to the nearest cm with the exception of 5 cm which only includes colonies >= 5 cm. Starting in 2016, measures less than 5 cm reflect colonies with thick branches which could only have <5 cm heights due to partial mortality.

Data Processing Description

BCO-DMO Processing:
- joined the Genus_Species from the species code list to the survey data;
- added site Latitude and Longitude columns using coordinates provided in metadata;
- replaced spaces with underscores in column names and in the Site names.

Data Files

File
stjohn_octocoral_abund_2019.csv (Comma Separated Values (.csv), 160.92 KB) MD5:3a62370a58e5b5dcfa28e499aa1513f4 Primary data file for dataset ID 793259

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1756381

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
Lasker_St_John		2014-07-17	Virgin Islands	Howard Lasker (Principal Investigator)	data info

Instruments

None available yet

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
Site	Site name	unitless	site
Latitude	Site latitude; converted from degrees decimal minutes to decimal degrees; positive values = N	decimal degrees	lat
Longitude	Site longitude; converted from degrees decimal minutes to decimal degrees; positive values = E	decimal degrees	lon
Census_Year	Four-digit year when the census took place; format: yyyy	unitless	year
Date	Date when the census took place; format: yyyy-mm-dd	unitless	date
Transect_Position	Transects positioned in a marked 50x10m area, with stainless steel eye bolts marking each corner, and each of the 6 transect. Transects were 10m long across the 50x10m area at 0m; 10m; 20m; 30m; 40m; 50m.	unitless	transect
Side_of_transect	Side of the transect tape (Left or Right), orientation looking towards open ocean, with the nearest shore to the back.	unitless	transect
Meter_on_transect	From 0m to 9m. 1x1m quadrats were positioned randomly along the 10 m transect. The values refer to the position of the "shoreward" corner of the quadrat. Thus "0"refers to the quadrat placed between the 0 and 1 meter marks	unitless	transect
Genus	Genus	unitless	genus
Species_code	Octocoral species code. Field identifications of Pseudoplexaura flagellosa and P. wagenaari are difficult and for analysis purposes the two species should be lumped as a single group. Field identifications of Eunicea mammosa, E. laxispica, and E. succinea are sometimes difficult, thus, for analysis purposes the three species should be lumped as a single group. Colonies identified as Plexaurella dichotoma include colonies with sclerites that match Bayer’s Plexaurella fusifera and whose branches best match a thin branch version P. nutans. aa2 is an undescribed Antillogorgia sp. similar in appearance to A. americana.	unitless	taxon_code
Genus_Species	Genus and species	unitless	species
Height_of_living_tissue	Maximum distance from the base of the octocoral colony until the farthest tips of the longest branch with living tissue (i.e. not necessarily perpendicular to the substrate). All measures rounded to the nearest cm with the exception of 5 cm which only includes colonies >= 5 cm. Measures less than 5 cm reflect colonies with thick branches which could only have <5 cm heights due to partial mortality.	centimeters (cm)	height
Total_height	Total height (dead and alive tissue)	centimeters (cm)	height
Basal_damage	Height (cm) from the base of the colony to living tissue. This value is 0.0 for colonies that have no damage to their base.	centimeters (cm)	height
Damage	Field estimate of the proportion of tissue on the colony that has been damaged: 1, <25%; 2, 25 to <50%; 3, 50 to <75%; 4, > 75% of the colony.	unitless	sample_descrip
Cyphoma_present	Number of individuals per colony	unitless	sample_descrip
Comments_1	Notes and comments. C. gibbosum denotes the presence of Cyphoma giibbosum, a grazing snail that strips living tissue from octocoral colonies. Millepora present: Inicates millepora overgrowing naked axis. Cyanobacteria present: Indicates Cyanobacteria growing on the colony. aa2 is new Antillogorgia sp.	unitless	comment
Comments_2_sample_tag_number	Notes and comments	unitless	comment