Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Related Datasets
• Parameters
• Instruments
• Project Information
• Funding

Recruit censuses were conducted in 2021 and 2021. Recruits (1 polyp - 5 centimeters tall) were enumerated, and when possible were identified to genus level in separate 0.25 square meter quadrats randomly placed (n = 8) along 6 transects at each of 3 sites (48 quadrats per site). Transects were positioned in a marked 50-meter x 10-meter area, with stainless steel eye bolts marking each corner, and each of the 6 transects. Transects were 10 meters long across the area.

Transect positions by site:
- Europa, Grootpan, and Tektite: transects were positioned in a marked 50 x 10 meter area, with stainless steel eye bolts marking each corner, and each of the 6 transects. Transects were 10 meters long across the area. So there were 0 meters; 10 meters; 20 meters; 30 meters; 40 meters; 50 meters.
- Booby Rock:  Surveys at Booby Rock were added in 2022. Transects were positioned at random points along a 100-meter line run parallel to the shore.  Transects ran downslope for 10 meters from the point on the 100-meter line.
- Deep Tektite, Yawzi: Three 10-meter transects positioned 10 meters apart along the reef edge and running perpendicular to the reef edge. 0.25 square meter quadrats were randomly placed (n = 16) along 3 transects at each site (48 quadrats per site).

Known Issues:
Eunicea spp. recruits that could not be identified to species were grouped into three groups based on the size of calyces:
Eunicea sp g1 – large polyps -Eunicea calyculata/clavigera/tournefortii/laciniata
Eunicea sp g2 – intermediate size with tubular calyces - Eunicea succinea/mammosa/laxispica
Eunicea sp g3 – small polyps - Eunicea asperula/flexuosa/knighti/palmeri/pinta/pallida

Notes:
- Octocoral recruits are defined as individuals greater than 5 centimeters in height.
- 8 quadrats were surveyed by transect but a few transects present differences in the number of quadrats surveyed.
- 0.1 centimeter or greater than 0.1 centimeter recruits are those with 1, 2, or 3 polyps and therefore not measurable.
- In the comments column: "No recruits present " indicates those quadrats surveyed without recruits.

BCO-DMO Processing description:
- Adjusted field/parameter names to comply with BCO-DMO naming conventions
- Missing data identifier ‘na’ replaced with blank (BCO-DMO's default missing data identifier)
- Added columns "Latitude" and "Longitude" based on site locations
- Rounded columns "Latitude" and "Longitude" to 3 decimal places
- Merged 2021 data and 2022 data into one dataset

NSF Award Abstract:
Coral reefs are exposed to a diversity of natural and anthropogenic disturbances, and the consequences for ecosystem degradation have been widely publicized. However, the reported changes have been biased towards fishes and stony corals, and for Caribbean reefs, the most notable example of this bias are octocorals ("soft corals"). Although they are abundant and dominate many Caribbean reefs, they are rarely included in studies due to the difficulty of both identifying them and in quantifying their abundances. In some places there is compelling evidence that soft corals have increased in abundance, even while stony corals have become less common. This suggests that soft corals are more resilient than stony corals to the wide diversity of disturbances that have been impacting coral corals. The best coral reefs on which to study these changes are those that have been studied for decades and can provide a decadal context to more recent events, and in this regard the reefs of St. John, US Virgin Islands are unique. Stony corals on the reefs have been studied since 1987, and the soft corals from 2014. This provides unrivalled platform to evaluate patterns of octocoral abundance and recruitment; identify the patterns of change that are occurring on these reefs, and identify the processes responsible for the resilience of octocoral populations. The project will extend soft coral monitoring from 4 years to 8 years, and within this framework will examine the roles of baby corals, and their response to seafloor roughness, seawater flow, and seaweed, in determining the success of soft corals. The work will also assess whether the destructive effects of Hurricanes Irma and Maria have modified the pattern of change. In concert with these efforts the project will be closely integrated with local high schools at which the investigators will host marine biology clubs and provide independent study opportunities for their students and teachers. Unique training opportunities will be provided to undergraduate and graduate students, as well as a postdoctoral researcher, all of whom will study and work in St. John, and the investigators will train coral reef researchers to identify the species of soft corals through a hands-on workshop to be conducted in the Florida Keys.

Understanding how changing environmental conditions will affect the community structure of major biomes is the ecological objective defining the 21st century. The holistic effects of these conditions on coral reefs will be studied on shallow reefs within the Virgin Islands National Park in St. John, US Virgin Islands, which is the site of one of the longest-running, long-term studies of coral reef community dynamics in the region. With NSF-LTREB support, the investigators have been studying long-term changes in stony coral communities in this location since 1987, and in 2014 NSF-OCE support was used to build an octocoral "overlay" to this decadal perspective. The present project extends from this unique history, which has been punctuated by the effects of Hurricanes Irma and Maria, to place octocoral synecology in a decadal context, and the investigators exploit a rich suite of legacy data to better understand the present and immediate future of Caribbean coral reefs. This four-year project will advance on two concurrent fronts: first, to extend time-series analyses of octocoral communities from four to eight years to characterize the pattern and pace of change in community structure, and second, to conduct a program of hypothesis-driven experiments focused on octocoral settlement that will uncover the mechanisms allowing octocorals to more effectively colonize substrata than scleractinian corals on present day reefs. Specifically, the investigators will conduct mensurative and manipulative experiments addressing four hypotheses focusing on the roles of: (1) habitat complexity in distinguishing between octocoral and scleractinian recruitment niches, (2) the recruitment niche in mediating post-settlement success, (3) competition in algal turf and macroalgae in determining the success of octocoral and scleractian recruits, and (4) role of octocoral canopies in modulating the flux of particles and larvae to the seafloor beneath. The results of this study will be integrated to evaluate the factors driving higher ecological resilience of octocorals versus scleractinians on present-day Caribbean reefs.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.