Dataset: octocoral transects - adult colony height

Name: Adult octocoral height measurements from transects conducted at St. John, US Virgin Islands between 2014-2016 (St. John LTREB project, VI_Octocorals)
Published: 2018-04-05
License: http://creativecommons.org/licenses/by/4.0/
Keywords: oceans

Cite This Dataset

Spatial Extent: N:18.31672 E:-64.71043 S:18.30293 W:-64.72993

Temporal Extent: 2014-07-29 - 2017-06-29

Project:

Ecology and functional biology of octocoral communities (VI Octocorals)

LTREB Long-term coral reef community dynamics in St. John, USVI: 1987-2019 (St. John LTREB)

Principal Investigator:

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

Contact:

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

BCO-DMO Data Manager:

Amber York (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version Date:

2018-04-05

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Data URL:

https://www.bco-dmo.org/dataset/682966/data

Adult octocoral height measurements from transects conducted at St. John, US Virgin Islands between 2014-2016 (St. John LTREB project, VI_Octocorals)

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Description

This dataset contains octocoral colony heights measured during transect surveys at four sites on the south shore of St. John, US Virgin Islands between 2014 to 2016.

Acquisition Description

Species names for field_codes in this dataset can be found in the related dataset: octocoral transects - species list

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. In 2014 ten quadrats were surveyed along each line. In 2015 and 2016 ten quadrats were scored along each transect line at Europa and Tektite and five randomly chosen quadrats were surveyed at East Cabritte. 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 4 transects were randomly placed along a 50 m line that was arbitrarily placed on a constant depth contour. Only 4 1x1 m quadrats were surveyed along each transect. The transect identifier (transect_pos) for transects at Booby Rock have values between 1-4 and are not related to position.

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.

Colony heights were measured as the maximum distance from the base of the octocoral colony until the farthest tips of the branch (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. Starting in 2016, measures less than 5 cm reflect colonies with thick branches which could only have <5 cm heights due to partial mortality.

Processing Description

Lines with no species entry identify quadrats in which no octocorals were present. This is also noted in the comments as "No colonies present."

No processing was conducted beyond loading and proofreading entries from field data sheets.

DATA NOTES & EDITS from data contributor:
29-Jul-14 2014- In the first transect at Booby Rock, some Plexaura spp. colonies (most likely Plexaura homomalla kukenthali) were incorrectly identified as P. kuna colonies. These have been changed changes to Plexaura sp
11-Sep-16 2014 - First Europa transect, now labelled "random" was arbitrarily placed on the reef before the 10x50 grid was laid out
2014 - All quadrats on right side of line
2014 - Europa, species notation ec2 on Comments 1 refers to colonies that appeared to be atypical E. calyculata
2014 - E Cabritte, species notation em2 on Comments 1 refers to colonies that appeared to be E. mammosa but may be Eunicea succinea
2014 - Comment 1: "Originally x": Miss-identification Missidentification in the field of the species "x", corrected after sclerites examination .
2015- All quadrats we positioned randomly on the left (L) or right (R) side of the transect line.
2015 -Species notation aa2 on Comments 1 refers to colonies that appeared to be A. americana but had somewhat broader branchlets and were not as slimy as classic A. americana. All aa2 colonies that were examined under stereoscope had A. americana sclerites.
2015 30-Jul-15 Europa 30 R 6 efl 4
2015- E Cabritte, Transect 20D - The transect line was incorrectly placed, running from the 20m eyebolt to the 30m eyebolt.
2015 - Comment 1: "Originally x": Miss-identification Missidentification in the field of the species "x", corrected after sclerites examination .
12-Sep-16 2016 - Colonies that on the basis of branch thickness are clearly not recruits but are <5 cm height are included as adults.
2016 - Comments 1: "Colony picture": Pictures were taken of some of the colonies for identification purposes
2016 - Europa, Transect 30D - The transect line was incorrectly placed, running from the 30m eyebolt to the 20m eyebolt.
2016 - Comments 1: "Originally x": Missidentification in the field of the species "x", corrected after sclerites examination .
2016 - Comments 1: "Thin form": A thinner form of E. clavigera
12-Sep-16 2016 - Recommendations for statistical analysis: Morphological similarities among certain species make the identification of some colonies in the field extremely difficult.

The conservative approach will be to use the following groups:
Eunicea group 1: em/esu/elc
Plexaurella group 1: pfu/pd
Pseudoplexaura group 1: pw/pp/pf

BCO-DMO Data Manager Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* blank values replaced with no data value 'nd'
* added lat lon of sites
* converted site locations from degrees decimal minutes to decimal degrees
* added species names based on species codes
* fixed switched values for E_Cabritte on 2016-07-26. Transect meter changed from R to 6 and transect side from 6 to R.
* sorted data by site, species, date, transect_pos
* the following code replacements and species name changes have been made to this dataset:
eusp -> esp and species "Eucinea sp"
ef -> efu and species "Eunicea fusca"
unk -> unknown
Eunicea lacinata -> Eunicea laciniata (accepted name)

Also, in comments andd -> and

Data verson 2017-03-20 replaced by version 2018-01-09 which updates site coordinates. Spelling corrections also made to "DATA NOTES & EDITS" section above.

Data version 2018-04-05 replaces version 2018-01-09. Data updated to include the sampling year 2017.
* in comments andd -> and
* species names along with field codes used in this dataset can be found in "species list" dataset https://www.bco-dmo.org/dataset/733063
* column names changed to match previous versions and species list (e.g. Species_code -> field_code)
* leading and trailing spaces removed from field codes

changes made to original line numbers to match entries on species list.
4757 - a - aa
3879 - am - ma
1527 - ef - efl
1536 - ef -efl
4117 - etop - eto
4384 - pv - pc
2152 - unk - pc
3085 - unk - pc

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1334052

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
Lasker_St_John_2012-2016		2014-07-17	Virgin Islands	Dr Howard Lasker (Principal Investigator)	data info

Instruments

Measuring Tape

(more info)

Short Name:

Generic Description

A tape measure or measuring tape is a flexible ruler. It consists of a ribbon of cloth, plastic, fibre glass, or metal strip with linear-measurement markings. It is a common measuring tool.

PI supplied instrument name: transect tape

Dataset-specific description

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
site	Site Name	unitless	site
lat	Site latitude; north is positive	decimal degrees	lat
lon	Site longitude; west is negative	decimal degrees	lon
field_code	Octocorals species acronyms	unitless	species
date	Date data was collected in format yyyy-mm-dd	unitless	date
transect_pos	Transect identifier; see acquisition description for details.	unitless	transect
transect_side	Side of the transect tape (L or R) orientation looking towards open ocean with the nearest shore to the back.	unitless	site_descrip
transect_m	Meter of 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.	meters	transect
height	Maximum distance from the base of the octocoral colony until the farthest tips of the branch. See acquisition description for more details.	centimeters	height
comment1	Comments about the dataset	unitless	comment
comment2	Sample Numbers for octocorals that were sampled in order to get IDs based on sclerites.	unitless	comment
year	year of census	unitless	year

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Dataset: octocoral transects - adult colony height