| Contributors | Affiliation | Role |
|---|---|---|
| Steneck, Robert S. | University of Maine (U Maine DMC) | Principal Investigator |
| Estes, James A. | University of California-Santa Cruz (UCSC) | Co-Principal Investigator |
| Rasher, Douglas B. | Bigelow Laboratory for Ocean Sciences | Co-Principal Investigator |
| Copley, Nancy | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Prior to examining Clathromorphum bioerosion at each focal study site, we characterized sea urchin community structure at each site by quantifying the density, size frequency distribution, and biomass of the sea urchin community (primarily Strongylocentrotus polyacanthus), using the same methods that have been employed by us and others over the past 30 years (Estes et al. 2010). We characterized two types of sites: (1) those that have long persisted as urchin barrens (“habitat.type” = “Barren”) and (2) urchin barrens that are situated immediately adjacent to shallow, remnant kelp stands, and thereby receive urchin food subsidies (“habitat.type” = “Barren + kelp subsidy”). At these latter sites, we also surveyed the adjacent kelp stand (“habitat.type” = “Shallow kelp”).
At each site, a diver placed a 0.25-m^2 quadrat at the target depth and counted all urchins within the quadrat, then collected the urchins in a bag. The diver then took a random number of kicks along the same depth contour and repeated this process until 20 quadrats were sampled or 200 urchins collected, whichever occurred first. If 200 urchins were collected quickly, additional density counts were made to yield a better density estimate (n = 4 minimum). Shipside, we measured the size (test diameter; mm) of each collected urchin with calipers. We then calculated its biomass using a known size-weight relationship (Estes et al. 2010). To estimate total urchin biomass for a site (grams per 0.25-m^2), we summed the biomass of all urchins collected at the site and divided that sum by the number of quadrats deployed.
BCO-DMO Processing Notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- re-formatted date from m/d/yyyy to yyyy-mm-dd
- converted west longitudes to negative values and removed E/W designations
- changed latitude for Kirilof Point from 51.14198 to 51.41198 as req'd by PI
| File |
|---|
target_biomass.csv (Comma Separated Values (.csv), 80.00 KB) MD5:606aced30ff013ceef33c893b601ef3b Primary data file for dataset ID 755243 |
| Parameter | Description | Units |
| island | name of island | unitless |
| site_name | identity of site | unitless |
| latitude | latitude of study site | decimal degrees |
| longitude | longitude of study site | decimal degrees |
| depth_feet | depth of benthic survey | feet |
| habitat_type | phase state of habitat: see Description | unitless |
| date | calendar date of survey formatted as yyyy-mm-dd | unitless |
| quadrat_count | number of 0.25-m^2 quadrats from which estimates were derived | quadrats |
| urchin_diameter_mm | diameter of urchin test (body) | millimeters |
| urchin_frequency | number of urchins collected within a size class | urchins |
| size_biomass_convert | urchin biomass; calculated using known size to dry weight relationship: =EXP(-7.857+(2.992*LN(urchin diameter))) | grams |
| sum_biomass_class | total biomass of all urchins collected within a given size class | grams |
| urchin_biomass_grams | urchin biomass per 0.25 m^2 per size class; calculated by dividing "sum.biomass.class" by "quadrat.count" | grams |
| Website | |
| Platform | R/V Point Sur |
| Start Date | 2014-07-05 |
| End Date | 2014-07-22 |
| Description | Benthic community studies associated with project "Project: Ocean Acidification: Century Scale Impacts to Ecosystem Structure and Function of Aleutian Kelp Forests". |
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.
NSF Climate Research Investment (CRI) activities that were initiated in 2010 are now included under Science, Engineering and Education for Sustainability NSF-Wide Investment (SEES). SEES is a portfolio of activities that highlights NSF's unique role in helping society address the challenge(s) of achieving sustainability. Detailed information about the SEES program is available from NSF (https://www.nsf.gov/funding/pgm_summ.jsp?pims_id=504707).
In recognition of the need for basic research concerning the nature, extent and impact of ocean acidification on oceanic environments in the past, present and future, the goal of the SEES: OA program is to understand (a) the chemistry and physical chemistry of ocean acidification; (b) how ocean acidification interacts with processes at the organismal level; and (c) how the earth system history informs our understanding of the effects of ocean acidification on the present day and future ocean.
Solicitations issued under this program:
NSF 10-530, FY 2010-FY2011
NSF 12-500, FY 2012
NSF 12-600, FY 2013
NSF 13-586, FY 2014
NSF 13-586 was the final solicitation that will be released for this program.
PI Meetings:
1st U.S. Ocean Acidification PI Meeting(March 22-24, 2011, Woods Hole, MA)
2nd U.S. Ocean Acidification PI Meeting(Sept. 18-20, 2013, Washington, DC)
3rd U.S. Ocean Acidification PI Meeting (June 9-11, 2015, Woods Hole, MA – Tentative)
NSF media releases for the Ocean Acidification Program:
Press Release 10-186 NSF Awards Grants to Study Effects of Ocean Acidification
Discovery Blue Mussels "Hang On" Along Rocky Shores: For How Long?
Press Release 13-102 World Oceans Month Brings Mixed News for Oysters
| Funding Source | Award |
|---|---|
| NSF Arctic Sciences (NSF ARC) |