Dataset: Sea urchin density Galápagos Islands

Name: Sea urchin (Eucidaris) quadrat counts at twelve sites in the Galápagos Islands in 2016-2017
Published: 2022-04-11
Keywords: Sea Urchin, rocky subtidal, community structure, biota, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.872905.1

Spatial Extent: N:-0.23696 E:-90.14065 S:-1.32879 W:-90.74908

Temporal Extent: 2016-07 - 2017-07

Project:

RAPID: Testing the ability of the 2015-2017 El Nino Southern Oscillation (ENSO) to drive a community-level regime shift in the Galapagos marine ecosystem (SPONGERAPDGALPGS)

Principal Investigator:

Jon D. Witman (Brown University)

BCO-DMO Data Manager:

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

Version:

Version Date:

2022-04-11

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Sea urchin (Eucidaris) quadrat counts at twelve sites in the Galápagos Islands in 2016-2017

Abstract:

Sea urchin (E. galapagensis) densities showed high variability across twelve study sites in the Galápagos Islands in 2016-2017. Sea urchin densities ranged from a low of 0.17 individuals per 0.25 square meter quadrat at the Pinzon site to a maximum of 7.7 individuals per quadrat at the Champion site in January 2016.

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2022-04-11	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.872905.1	2022-04-26

Methods & Sampling

Quadrat survey techniques were used at twelve sites in the Galápagos Islands in 2016-2017 to determine counts and species density of Eucidaris sea urchins. Quadrats were 0.25 square meter areas randomly established following the methods of Witman and Smith (2003). A ‘quadrapod’ camera framer holding an underwater camera was used to capture digital photo quadrat images (42 megapixel resolution) which were subsequently viewed on a computer. This was the same field sampling method described in Witman and Smith (2003) except this study used a Sony AR digital camera in a Nauticam underwater housing. The sampling was achieved by a diver swimming along the transect tape and taking photo quadrats at the random marks on the tape. The large thick spines of the Eucidaris galapagensis enable the sea urchins to be readily recognized and counted. Sea urchins were manually counted from digital images of the quadrats (photo quadrats) displayed on a computer screen. The counts were then entered by quadrat and site into an Excel spreadsheet.

Data Files

File
sea_urchin_density.csv (Comma Separated Values (.csv), 29.05 KB) MD5:ff8ea725631131a4dee91f13fa67e6e2 Primary data file for dataset ID 872905

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1623867

Deployments

None available yet

Instruments

Camera

Supplied Name: Sony AR digital camera

Supplied Description:

A Sony AR digital camera in Nauticam underwater housing was used to capture digital photo quadrat images

Instrument Type

Generic Name: Camera

Acronym: camera

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/311/

Generic Description:

All types of photographic equipment including stills, video, film and digital systems.

Diving Mask and Snorkel

Supplied Name:

Supplied Description:

The sampling was achieved by a diver swimming along the transect tape and taking photos

Instrument Type

Generic Name: Diving Mask and Snorkel

Generic Description:

A diving mask (also half mask, dive mask or scuba mask) is an item of diving equipment that allows underwater divers, including, scuba divers, free-divers, and snorkelers to see clearly underwater.

Snorkel: A breathing apparatus for swimmers and surface divers that allows swimming or continuous use of a face mask without lifting the head to breathe, consisting of a tube that curves out of the mouth and extends above the surface of the water.

ruler

Supplied Name: millimeter scale for photo images

Supplied Description:

A scale (mm) on the sides of the quadrat allowed measurement of organisms in the images.

Instrument Type

Generic Name: ruler

Generic Description:

A device used for measuring or for drawing straight lines, consisting of an elongated piece of rigid or semi-rigid material marked with units for measurement. Device that allows one or more physical dimensions of a sample or specimen to be determined by visible comparison against marked graduations in units of measurement of dimension length.

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
Year	Year of sample collection	unitless	year
Month	Month of sample collection	unitless	month
Latitude	Latitude of sample collection	decimal degrees	lat
Longitude	Longitude of sample collection	decimal degrees	lon
Site	Study site in the central Galapagos archipelago where samples were collected	unitless	site
Quadrat_number	Quadrat number indicating the independent 0.25 square meter area	unitless	Site_ID
Eucidaris_density	Sea urchin density or number of Eucidaris galapagensis photographed in the quadrat	unitless	abundance

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Database

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Dataset: Sea urchin density Galápagos Islands