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Dataset Title:  Sea urchin bio-erosion of Clathromorphum nereostratum skeleton at central and
western Aleutian Islands, Alaska from visual surveys, July 2014
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Institution:  BCO-DMO   (Dataset ID: bcodmo_dataset_755299)
Information:  Summary ? | License ? | Metadata | Background (external link) | Files | Make a graph
Variable ?   Optional
Constraint #1 ?
Constraint #2 ?
   Minimum ?
   Maximum ?
 island (unitless) ?          "Alaid"    "Ogliuga"
 site_name (unitless) ?          "Bat Island"    "Site 6"
 latitude (degrees_north) ?          51.41198    52.9306
  < slider >
 longitude (degrees_east) ?          -178.68897    179.29806
  < slider >
 depth_feet (Depth, feet) ?          20.0    40.0
 habitat_type (unitless) ?          "Barren"    "Barren + kelp subs..."
 time (Date, UTC) ?          2014-07-08    2014-07-21
  < slider >
 replicate (unitless) ?          1    11
 Clathromorphum_cover (percent) ?          35    100
 grazed_score (unitless) ?          1    6
 quality_rank (unitless) ?          1    3
 grazed_cover_median (percent) ?          2.5    98.0
 max_depth_grazed_mm (millimeters) ?          0.15    10.0
 pit_volume_cm3 (centimeters^3) ?          0.0    14519.36
Server-side Functions ?
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The Dataset Attribute Structure (.das) for this Dataset

Attributes {
 s {
  island {
    String bcodmo_name "site";
    String description "name of island";
    String long_name "Island";
    String units "unitless";
  site_name {
    String bcodmo_name "site";
    String description "identity of site";
    String long_name "Site Name";
    String units "unitless";
  latitude {
    String _CoordinateAxisType "Lat";
    Float64 _FillValue NaN;
    Float64 actual_range 51.41198, 52.9306;
    String axis "Y";
    String bcodmo_name "latitude";
    Float64 colorBarMaximum 90.0;
    Float64 colorBarMinimum -90.0;
    String description "latitude of study site";
    String ioos_category "Location";
    String long_name "Latitude";
    String nerc_identifier "https://vocab.nerc.ac.uk/collection/P09/current/LATX/";
    String standard_name "latitude";
    String units "degrees_north";
  longitude {
    String _CoordinateAxisType "Lon";
    Float64 _FillValue NaN;
    Float64 actual_range -178.68897, 179.29806;
    String axis "X";
    String bcodmo_name "longitude";
    Float64 colorBarMaximum 180.0;
    Float64 colorBarMinimum -180.0;
    String description "longitude of study site";
    String ioos_category "Location";
    String long_name "Longitude";
    String nerc_identifier "https://vocab.nerc.ac.uk/collection/P09/current/LONX/";
    String standard_name "longitude";
    String units "degrees_east";
  depth_feet {
    Float64 _FillValue NaN;
    Float64 actual_range 20.0, 40.0;
    String bcodmo_name "depth";
    Float64 colorBarMaximum 8000.0;
    Float64 colorBarMinimum -8000.0;
    String colorBarPalette "TopographyDepth";
    String description "depth of benthic survey";
    String long_name "Depth";
    String nerc_identifier "https://vocab.nerc.ac.uk/collection/P09/current/DEPH/";
    String standard_name "depth";
    String units "feet";
  habitat_type {
    String bcodmo_name "site_descrip";
    String description "phase state of habitat: see Description";
    String long_name "Habitat Type";
    String units "unitless";
  time {
    String _CoordinateAxisType "Time";
    Float64 actual_range 1.4047776e+9, 1.4059008e+9;
    String axis "T";
    String bcodmo_name "date";
    String description "calendar date of survey formatted as yyyy-mm-dd";
    String ioos_category "Time";
    String long_name "Date";
    String nerc_identifier "https://vocab.nerc.ac.uk/collection/P01/current/ADATAA01/";
    String source_name "date";
    String standard_name "time";
    String time_origin "01-JAN-1970 00:00:00";
    String time_precision "1970-01-01";
    String units "seconds since 1970-01-01T00:00:00Z";
  replicate {
    Byte _FillValue 127;
    Byte actual_range 1, 11;
    String bcodmo_name "replicate";
    String description "replicate 0.25-m^2 quadrat identifier";
    String long_name "Replicate";
    String units "unitless";
  Clathromorphum_cover {
    Byte _FillValue 127;
    Byte actual_range 35, 100;
    String bcodmo_name "cover_pcent";
    String description "abundance of alga in photo";
    String long_name "Clathromorphum Cover";
    String units "percent";
  grazed_score {
    Byte _FillValue 127;
    Byte actual_range 1, 6;
    String bcodmo_name "unknown";
    String description "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.";
    String long_name "Grazed Score";
    String units "unitless";
  quality_rank {
    Byte _FillValue 127;
    Byte actual_range 1, 3;
    String bcodmo_name "q_flag";
    Float64 colorBarMaximum 150.0;
    Float64 colorBarMinimum 0.0;
    String description "quality of (confidence in) \"grazed.score\" measurement: 1 (excellent); 2 (good);  or 3 (poor)";
    String long_name "Quality Rank";
    String units "unitless";
  grazed_cover_median {
    Float32 _FillValue NaN;
    Float32 actual_range 2.5, 98.0;
    String bcodmo_name "cover_pcent";
    String description "conversion of \"grazed.score\" units to % cover (median of range)";
    String long_name "Grazed Cover Median";
    String units "percent";
  max_depth_grazed_mm {
    Float32 _FillValue NaN;
    Float32 actual_range 0.15, 10.0;
    String bcodmo_name "depth";
    String description "maximum depth of sea urchin grazing scar on collected sample";
    String long_name "Max Depth Grazed Mm";
    String nerc_identifier "https://vocab.nerc.ac.uk/collection/P09/current/DEPH/";
    String units "millimeters";
  pit_volume_cm3 {
    Float64 _FillValue NaN;
    Float64 actual_range 0.0, 14519.36;
    String bcodmo_name "volume";
    String description "volume of large pit excavated by sea urchins; approximated as the volume of a half cylinder";
    String long_name "Pit Volume Cm3";
    String units "centimeters^3";
    String access_formats ".htmlTable,.csv,.json,.mat,.nc,.tsv,.esriCsv,.geoJson,.odvTxt";
    String acquisition_description 
"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.";
    String awards_0_award_nid "526658";
    String awards_0_award_number "PLR-1316141";
    String awards_0_data_url "http://nsf.gov/awardsearch/showAward?AWD_ID=1316141";
    String awards_0_funder_name "NSF Arctic Sciences";
    String awards_0_funding_acronym "NSF ARC";
    String awards_0_funding_source_nid "390";
    String awards_0_program_manager "Henrietta N Edmonds";
    String awards_0_program_manager_nid "51517";
    String cdm_data_type "Other";
    String comment 
   Aleutian Islands, AK, July 2014 
   PI's: R. Steneck (UME), J. Estes (UCSCD) 
   version: 2019-01-30";
    String Conventions "COARDS, CF-1.6, ACDD-1.3";
    String creator_email "info@bco-dmo.org";
    String creator_name "BCO-DMO";
    String creator_type "institution";
    String creator_url "https://www.bco-dmo.org/";
    String data_source "extract_data_as_tsv version 2.3  19 Dec 2019";
    String date_created "2019-02-07T15:12:17Z";
    String date_modified "2019-02-25T20:05:40Z";
    String defaultDataQuery "&amp;time&lt;now";
    String doi "10.1575/1912/bco-dmo.755299.1";
    Float64 Easternmost_Easting 179.29806;
    Float64 geospatial_lat_max 52.9306;
    Float64 geospatial_lat_min 51.41198;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 179.29806;
    Float64 geospatial_lon_min -178.68897;
    String geospatial_lon_units "degrees_east";
    String history 
"2021-11-29T05:00:23Z (local files)
2021-11-29T05:00:23Z https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_755299.html";
    String infoUrl "https://www.bco-dmo.org/dataset/755299";
    String institution "BCO-DMO";
    String keywords "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";
    String license "https://www.bco-dmo.org/dataset/755299/license";
    String metadata_source "https://www.bco-dmo.org/api/dataset/755299";
    Float64 Northernmost_Northing 52.9306;
    String param_mapping "{'755299': {'date': 'flag - time', 'depth_feet': 'flag - depth', 'longitude': 'flag - longitude', 'latitude': 'flag - latitude'}}";
    String parameter_source "https://www.bco-dmo.org/mapserver/dataset/755299/parameters";
    String people_0_affiliation "University of Maine";
    String people_0_affiliation_acronym "U Maine DMC";
    String people_0_person_name "Robert  S. Steneck";
    String people_0_person_nid "526659";
    String people_0_role "Principal Investigator";
    String people_0_role_type "originator";
    String people_1_affiliation "University of California-Santa Cruz";
    String people_1_affiliation_acronym "UC Santa Cruz";
    String people_1_person_name "James Estes";
    String people_1_person_nid "51389";
    String people_1_role "Co-Principal Investigator";
    String people_1_role_type "originator";
    String people_2_affiliation "Bigelow Laboratory for Ocean Sciences";
    String people_2_person_name "Douglas B. Rasher";
    String people_2_person_nid "480721";
    String people_2_role "Co-Principal Investigator";
    String people_2_role_type "originator";
    String people_3_affiliation "Woods Hole Oceanographic Institution";
    String people_3_affiliation_acronym "WHOI BCO-DMO";
    String people_3_person_name "Nancy Copley";
    String people_3_person_nid "50396";
    String people_3_role "BCO-DMO Data Manager";
    String people_3_role_type "related";
    String project "OA Kelp Forest Function";
    String projects_0_acronym "OA Kelp Forest Function";
    String projects_0_description 
"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.";
    String projects_0_end_date "2016-08";
    String projects_0_name "Ocean Acidification:  Century Scale Impacts to Ecosystem Structure and Function of Aleutian Kelp Forests";
    String projects_0_project_nid "526660";
    String projects_0_start_date "2013-09";
    String publisher_name "Biological and Chemical Oceanographic Data Management Office (BCO-DMO)";
    String publisher_type "institution";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing 51.41198;
    String standard_name_vocabulary "CF Standard Name Table v55";
    String summary "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.";
    String time_coverage_end "2014-07-21";
    String time_coverage_start "2014-07-08";
    String title "Sea urchin bio-erosion of Clathromorphum nereostratum skeleton at central and western Aleutian Islands, Alaska from visual surveys, July 2014";
    String version "1";
    Float64 Westernmost_Easting -178.68897;
    String xml_source "osprey2erddap.update_xml() v1.3";


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