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Institution Dataset ID
     data   graph     files  public Sea urchin bio-erosion of Clathromorphum nereostratum skeleton at central and western
Aleutian Islands, Alaska from visual surveys, July 2014
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The Dataset's Variables and Attributes

Row Type Variable Name Attribute Name Data Type Value
attribute NC_GLOBAL access_formats String .htmlTable,.csv,.json,.mat,.nc,.tsv,.esriCsv,.geoJson,.odvTxt
attribute NC_GLOBAL acquisition_description String We quantified the degree to which urchins have overgrazed Clathromorphum
nereostratum across our 700-km study area. To do so, we haphazardly selected a
single site at each island for high-resolution study (\"habitat.type\" =
\"Barren\"), which were of comparable depth (30-40 feet), harbored an
abundance of C. nereostratum, and have a known ecological history. We also
studied new sites at Ogliuga, Amchitka, Kiska (Rat Islands), Nizki (Semichi
Islands), and Attu that met the same depth and benthic composition criteria
but were situated adjacent to shallow (15-24 feet depth) remnant kelp stands;
detailed study of these barren sites (\"habitat.type\" = \"Barren + kelp
subsidy\") allowed us to document patterns of bioerosion in the presence of
kelp-derived urchin food subsidies. We also visited similar sites at Adak and
Tanaga to survey bioerosion, but these survey data were omitted due to
sampling error and/or violation of site criteria.

To assess the proportion of C. nereostratum that was overgrazed at each study
site, we visually estimated bioerosion using photo quadrat surveys. At each
site, a diver descended to the reef and set a random compass bearing, swam in
the direction of that bearing for a predetermined number of kicks, and placed
a 25 x 25 cm quadrat on the nearest C. nereostratum colony. The diver then
took a full frame, high-resolution photo of the quadrat (camera: Canon 5D Mark
II DSLR camera with Ikelite DS-150 strobes; lens: Canon 15mm fisheye, mounted
on a Kenko 1.4x teleconverter to narrow the field of view and reduce
distortion). This process was repeated, photographing C. nereostratum
individuals every two body lengths (~4 m distance; n = 10/site). In the lab,
photos were corrected for lens barrel distortion, cropped, and edited for
brightness, saturation, and contrast in Adobe Photoshop Elements. Using a grid
(1 x 1 cm) overlay, we visually estimated C. nereostratum abundance within
each quadrat (\"Clathromorphum.cover\"). We then estimated the proportion of
the alga grazed by urchins (\"grazed.score\"), using a scale of 1-6 (where 1 =
0-5%, 2 = 6-25%, 3 = 26-50%, 4 = 51-75%, 5 = 76-95%, and 6 = 96-100 % cover
grazed), as the presence of white perithallus indicates overgrazing to a depth
> 250 micrometers, below the meristem layer that is responsible for growth and
reproduction. Overgrazing scores were ranked (1-3) because photo quality
varied depending on field conditions (\"quality.rank\"). Low confidence
estimates (rank 3 of 3) were removed from the analysis, as were measurements
made in excess of n = 10 per site. We assumed all grazing was due to urchins,
as they are the only large herbivore in the ecosystem and their bite scars are
easy to identify.

To measure the depth (in millimeters) to which urchins grazed C nereostratum
(\"max.depth.grazed.mm\"), a second diver haphazardly removed a small sample
of the alga from each photoquadrat (after the photo was taken) with hammer and
chisel. In the laboratory, the depth of the most pronounced pentaradial urchin
grazing scar on each sample was measured using a microscope with ocular

Finally, to estimate the prevalence of larger grazed features (excavation
pits) in the field, which represent the cumulative impacts of grazing over
decades to centuries, at each interval where photoquadrats were deployed the
second diver also measured the dimensions of the nearest excavation pit
(\"pit.volume.cm^3\") generated by grazing (n = 10/site). Each pit was
measured with respect to its length, width, and depth (cm). We then
approximated the volume of each pit as a half cylinder using the equation V =
1/2[PI]r2h, where r was the depth and h the length of the pit.
attribute NC_GLOBAL awards_0_award_nid String 526658
attribute NC_GLOBAL awards_0_award_number String PLR-1316141
attribute NC_GLOBAL awards_0_data_url String http://nsf.gov/awardsearch/showAward?AWD_ID=1316141 (external link)
attribute NC_GLOBAL awards_0_funder_name String NSF Arctic Sciences
attribute NC_GLOBAL awards_0_funding_acronym String NSF ARC
attribute NC_GLOBAL awards_0_funding_source_nid String 390
attribute NC_GLOBAL awards_0_program_manager String Henrietta N Edmonds
attribute NC_GLOBAL awards_0_program_manager_nid String 51517
attribute NC_GLOBAL cdm_data_type String Other
attribute NC_GLOBAL comment String target_site_benthic_survey_reef_bioerosion_2014
Aleutian Islands, AK, July 2014
PI's: R. Steneck (UME), J. Estes (UCSCD)
version: 2019-01-30
attribute NC_GLOBAL Conventions String COARDS, CF-1.6, ACDD-1.3
attribute NC_GLOBAL creator_email String info at bco-dmo.org
attribute NC_GLOBAL creator_name String BCO-DMO
attribute NC_GLOBAL creator_type String institution
attribute NC_GLOBAL creator_url String https://www.bco-dmo.org/ (external link)
attribute NC_GLOBAL data_source String extract_data_as_tsv version 2.3 19 Dec 2019
attribute NC_GLOBAL date_created String 2019-02-07T15:12:17Z
attribute NC_GLOBAL date_modified String 2019-02-25T20:05:40Z
attribute NC_GLOBAL defaultDataQuery String &time<now
attribute NC_GLOBAL doi String 10.1575/1912/bco-dmo.755299.1
attribute NC_GLOBAL Easternmost_Easting double 179.29806
attribute NC_GLOBAL geospatial_lat_max double 52.9306
attribute NC_GLOBAL geospatial_lat_min double 51.41198
attribute NC_GLOBAL geospatial_lat_units String degrees_north
attribute NC_GLOBAL geospatial_lon_max double 179.29806
attribute NC_GLOBAL geospatial_lon_min double -178.68897
attribute NC_GLOBAL geospatial_lon_units String degrees_east
attribute NC_GLOBAL infoUrl String https://www.bco-dmo.org/dataset/755299 (external link)
attribute NC_GLOBAL institution String BCO-DMO
attribute NC_GLOBAL keywords String bco, bco-dmo, biological, chemical, clathromorphum, Clathromorphum_cover, cm3, cover, data, dataset, date, depth, depth_feet, dmo, erddap, grazed, grazed_cover_median, grazed_score, habitat, habitat_type, island, latitude, longitude, management, max, max_depth_grazed_mm, median, name, oceanography, office, pit, pit_volume_cm3, preliminary, quality, quality_rank, rank, replicate, score, site, site_name, time, type, volume
attribute NC_GLOBAL license String https://www.bco-dmo.org/dataset/755299/license (external link)
attribute NC_GLOBAL metadata_source String https://www.bco-dmo.org/api/dataset/755299 (external link)
attribute NC_GLOBAL Northernmost_Northing double 52.9306
attribute NC_GLOBAL param_mapping String {'755299': {'date': 'flag - time', 'depth_feet': 'flag - depth', 'longitude': 'flag - longitude', 'latitude': 'flag - latitude'}}
attribute NC_GLOBAL parameter_source String https://www.bco-dmo.org/mapserver/dataset/755299/parameters (external link)
attribute NC_GLOBAL people_0_affiliation String University of Maine
attribute NC_GLOBAL people_0_affiliation_acronym String U Maine DMC
attribute NC_GLOBAL people_0_person_name String Robert S. Steneck
attribute NC_GLOBAL people_0_person_nid String 526659
attribute NC_GLOBAL people_0_role String Principal Investigator
attribute NC_GLOBAL people_0_role_type String originator
attribute NC_GLOBAL people_1_affiliation String University of California-Santa Cruz
attribute NC_GLOBAL people_1_affiliation_acronym String UC Santa Cruz
attribute NC_GLOBAL people_1_person_name String James Estes
attribute NC_GLOBAL people_1_person_nid String 51389
attribute NC_GLOBAL people_1_role String Co-Principal Investigator
attribute NC_GLOBAL people_1_role_type String originator
attribute NC_GLOBAL people_2_affiliation String Bigelow Laboratory for Ocean Sciences
attribute NC_GLOBAL people_2_person_name String Douglas B. Rasher
attribute NC_GLOBAL people_2_person_nid String 480721
attribute NC_GLOBAL people_2_role String Co-Principal Investigator
attribute NC_GLOBAL people_2_role_type String originator
attribute NC_GLOBAL people_3_affiliation String Woods Hole Oceanographic Institution
attribute NC_GLOBAL people_3_affiliation_acronym String WHOI BCO-DMO
attribute NC_GLOBAL people_3_person_name String Nancy Copley
attribute NC_GLOBAL people_3_person_nid String 50396
attribute NC_GLOBAL people_3_role String BCO-DMO Data Manager
attribute NC_GLOBAL people_3_role_type String related
attribute NC_GLOBAL project String OA Kelp Forest Function
attribute NC_GLOBAL projects_0_acronym String OA Kelp Forest Function
attribute NC_GLOBAL projects_0_description String Extracted from the NSF award abstract:
Marine calcifying organisms are most at risk to rapid ocean acidification (OA) in cold-water ecosystems. The investigators propose to determine if a globally unique and widespread calcareous alga in Alaska's Aleutian archipelago, Clathromorphum nereostratum, is threatened with extinction due to the combined effects of OA and food web alterations. C. nereostratum is a slow growing coralline alga that can live to at least 2000 years. It accretes massive 'bioherms' that dominate the regions' rocky substrate both under kelp forests and deforested sea urchin barrens. It develops growth bands (similar to tree rings) in its calcareous skeleton, which effectively record its annual calcification rate over centuries. Pilot data suggest the skeletal density of C. nereostratum began to decline precipitously in the 1990's in some parts of the Aleutian archipelago. The investigators now propose to use high-resolution microscopy and microCT imaging to examine how the growth and skeletal density of C. nereostratum has changed in the past 300 years (i.e., since the industrial revolution) across the western Aleutians. They will compare their records of algal skeletal densities and their variation through time with reconstructions of past climate to infer causes of change. In addition, the investigators will examine whether the alga's defense against grazing by sea urchins is compromised by ongoing ocean acidification. The investigators will survey the extent of C. nereostratum bioerosion occurring at 10 sites spanning the western Aleutians, both inside and outside of kelp forests. At each site they will compare these patterns to observed and monitored ecosystem trophic structure and recent C. nereostratum calcification rates. Field observations will be combined with laboratory experiments to determine if it is a decline in the alga's skeletal density (due to recent OA and warming), an increase in grazing intensity (due to recent trophic-level dysfunction), or their interactive effects that are likely responsible for bioerosion patterns inside vs. outside of forests. By sampling C. nereostratum inside and outside of forests, they will determine if kelp forests locally increase pH via photosynthesis, and thus buffer the effects of OA on coralline calcification. The combination of field observations with laboratory controlled experiments, manipulating CO2 and temperature, will help elucidate drivers of calcification and project how these species interactions will likely change in the near future. The project will provide the first in situ example of how ongoing ocean acidification is affecting the physiology of long-lived, carbonate producing organisms in the subarctic North Pacific. It will also be one of the first studies to document whether OA, ocean warming, and food web changes to ecological processes are interacting in complex ways to reshape the outcome of species interactions in nature.
attribute NC_GLOBAL projects_0_end_date String 2016-08
attribute NC_GLOBAL projects_0_name String Ocean Acidification: Century Scale Impacts to Ecosystem Structure and Function of Aleutian Kelp Forests
attribute NC_GLOBAL projects_0_project_nid String 526660
attribute NC_GLOBAL projects_0_start_date String 2013-09
attribute NC_GLOBAL publisher_name String Biological and Chemical Oceanographic Data Management Office (BCO-DMO)
attribute NC_GLOBAL publisher_type String institution
attribute NC_GLOBAL sourceUrl String (local files)
attribute NC_GLOBAL Southernmost_Northing double 51.41198
attribute NC_GLOBAL standard_name_vocabulary String CF Standard Name Table v55
attribute NC_GLOBAL summary String Characterization of the degree to which sea urchins have excavated (bio-eroded) the calcium carbonate skeleton of Clathromorphum nereostratum, a long-lived reef-building coralline alga that forms the structural base of the kelp forest. Estimates were derived from field measurements, photoquadrat surveys, and collections, all performed via SCUBA.
attribute NC_GLOBAL time_coverage_end String 2014-07-21
attribute NC_GLOBAL time_coverage_start String 2014-07-08
attribute NC_GLOBAL title String Sea urchin bio-erosion of Clathromorphum nereostratum skeleton at central and western Aleutian Islands, Alaska from visual surveys, July 2014
attribute NC_GLOBAL version String 1
attribute NC_GLOBAL Westernmost_Easting double -178.68897
attribute NC_GLOBAL xml_source String osprey2erddap.update_xml() v1.3
variable island   String  
attribute island bcodmo_name String site
attribute island description String name of island
attribute island long_name String Island
attribute island units String unitless
variable site_name   String  
attribute site_name bcodmo_name String site
attribute site_name description String identity of site
attribute site_name long_name String Site Name
attribute site_name units String unitless
variable latitude   double  
attribute latitude _CoordinateAxisType String Lat
attribute latitude _FillValue double NaN
attribute latitude actual_range double 51.41198, 52.9306
attribute latitude axis String Y
attribute latitude bcodmo_name String latitude
attribute latitude colorBarMaximum double 90.0
attribute latitude colorBarMinimum double -90.0
attribute latitude description String latitude of study site
attribute latitude ioos_category String Location
attribute latitude long_name String Latitude
attribute latitude nerc_identifier String https://vocab.nerc.ac.uk/collection/P09/current/LATX/ (external link)
attribute latitude standard_name String latitude
attribute latitude units String degrees_north
variable longitude   double  
attribute longitude _CoordinateAxisType String Lon
attribute longitude _FillValue double NaN
attribute longitude actual_range double -178.68897, 179.29806
attribute longitude axis String X
attribute longitude bcodmo_name String longitude
attribute longitude colorBarMaximum double 180.0
attribute longitude colorBarMinimum double -180.0
attribute longitude description String longitude of study site
attribute longitude ioos_category String Location
attribute longitude long_name String Longitude
attribute longitude nerc_identifier String https://vocab.nerc.ac.uk/collection/P09/current/LONX/ (external link)
attribute longitude standard_name String longitude
attribute longitude units String degrees_east
variable depth_feet   double  
attribute depth_feet _FillValue double NaN
attribute depth_feet actual_range double 20.0, 40.0
attribute depth_feet bcodmo_name String depth
attribute depth_feet colorBarMaximum double 8000.0
attribute depth_feet colorBarMinimum double -8000.0
attribute depth_feet colorBarPalette String TopographyDepth
attribute depth_feet description String depth of benthic survey
attribute depth_feet long_name String Depth
attribute depth_feet nerc_identifier String https://vocab.nerc.ac.uk/collection/P09/current/DEPH/ (external link)
attribute depth_feet standard_name String depth
attribute depth_feet units String feet
variable habitat_type   String  
attribute habitat_type bcodmo_name String site_descrip
attribute habitat_type description String phase state of habitat: see Description
attribute habitat_type long_name String Habitat Type
attribute habitat_type units String unitless
variable time   double  
attribute time _CoordinateAxisType String Time
attribute time actual_range double 1.4047776E9, 1.4059008E9
attribute time axis String T
attribute time bcodmo_name String date
attribute time description String calendar date of survey formatted as yyyy-mm-dd
attribute time ioos_category String Time
attribute time long_name String Date
attribute time nerc_identifier String https://vocab.nerc.ac.uk/collection/P01/current/ADATAA01/ (external link)
attribute time source_name String date
attribute time standard_name String time
attribute time time_origin String 01-JAN-1970 00:00:00
attribute time time_precision String 1970-01-01
attribute time units String seconds since 1970-01-01T00:00:00Z
variable replicate   byte  
attribute replicate _FillValue byte 127
attribute replicate actual_range byte 1, 11
attribute replicate bcodmo_name String replicate
attribute replicate description String replicate 0.25-m^2 quadrat identifier
attribute replicate long_name String Replicate
attribute replicate units String unitless
variable Clathromorphum_cover   byte  
attribute Clathromorphum_cover _FillValue byte 127
attribute Clathromorphum_cover actual_range byte 35, 100
attribute Clathromorphum_cover bcodmo_name String cover_pcent
attribute Clathromorphum_cover description String abundance of alga in photo
attribute Clathromorphum_cover long_name String Clathromorphum Cover
attribute Clathromorphum_cover units String percent
variable grazed_score   byte  
attribute grazed_score _FillValue byte 127
attribute grazed_score actual_range byte 1, 6
attribute grazed_score bcodmo_name String unknown
attribute grazed_score description String proportion of colony grazed: percent cover per colony estimated using a score of 1-6 where 1 = 0-5%; 2 = 6-25%; 3 = 26-50%; 4 = 51-75%; 5 = 76-95%; and 6 = 96-100 % cover grazed.
attribute grazed_score long_name String Grazed Score
attribute grazed_score units String unitless
variable quality_rank   byte  
attribute quality_rank _FillValue byte 127
attribute quality_rank actual_range byte 1, 3
attribute quality_rank bcodmo_name String q_flag
attribute quality_rank colorBarMaximum double 150.0
attribute quality_rank colorBarMinimum double 0.0
attribute quality_rank description String quality of (confidence in) "grazed.score" measurement: 1 (excellent); 2 (good); or 3 (poor)
attribute quality_rank long_name String Quality Rank
attribute quality_rank units String unitless
variable grazed_cover_median   float  
attribute grazed_cover_median _FillValue float NaN
attribute grazed_cover_median actual_range float 2.5, 98.0
attribute grazed_cover_median bcodmo_name String cover_pcent
attribute grazed_cover_median description String conversion of "grazed.score" units to % cover (median of range)
attribute grazed_cover_median long_name String Grazed Cover Median
attribute grazed_cover_median units String percent
variable max_depth_grazed_mm   float  
attribute max_depth_grazed_mm _FillValue float NaN
attribute max_depth_grazed_mm actual_range float 0.15, 10.0
attribute max_depth_grazed_mm bcodmo_name String depth
attribute max_depth_grazed_mm description String maximum depth of sea urchin grazing scar on collected sample
attribute max_depth_grazed_mm long_name String Max Depth Grazed Mm
attribute max_depth_grazed_mm nerc_identifier String https://vocab.nerc.ac.uk/collection/P09/current/DEPH/ (external link)
attribute max_depth_grazed_mm units String millimeters
variable pit_volume_cm3   double  
attribute pit_volume_cm3 _FillValue double NaN
attribute pit_volume_cm3 actual_range double 0.0, 14519.36
attribute pit_volume_cm3 bcodmo_name String volume
attribute pit_volume_cm3 description String volume of large pit excavated by sea urchins; approximated as the volume of a half cylinder
attribute pit_volume_cm3 long_name String Pit Volume Cm3
attribute pit_volume_cm3 units String centimeters^3

The information in the table above is also available in other file formats (.csv, .htmlTable, .itx, .json, .jsonlCSV1, .jsonlCSV, .jsonlKVP, .mat, .nc, .nccsv, .tsv, .xhtml) via a RESTful web service.

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