Data Management Plan

The calcification rate data described here are from calcification accretion units (CAUs) that have been retrieved (and replaced) at existing, long-term monitoring sites during the NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML) led NCRMP missions around the Dry Tortugas in 2015 and 2018 and processed at the NOAA Pacific Islands Fisheries Science Center. CAUs are PVC settlement plates that facilitate the recruitment and colonization of crustose coralline algae, hard corals, and other reef calcifiers. Laboratory experiments show that CCA and coral calcification rates are strongly correlated with seawater chemistry, and shifts in carbonate chemistry conditions due to ocean acidification could lead to reduced calcification and accretion rates and ecological phase shifts in coral reef communities.

Coral reef calcium carbonate accretion rates can be estimated by measuring the change in weight of the CAUs between deployment and retrieval. Monitoring net accretion over successive deployments allows for the detection of changes in reef calcification rates over time. Five units were deployed on the seafloor at each CAU site for 3 years. The number of processed CAUs for a site may be less than the number deployed, either because the units were lost or damaged at sea and therefore not recovered, or in rare instances, due to errors during laboratory processing.

This study provides information about spatial and temporal patterns of reef carbonate calcification and accretion rates and serves as a basis for detecting changes associated with changing seawater chemistry due to ocean acidification. These data can also be used in comparative analyses across natural gradients, thereby assisting efforts to determine whether key reef-building taxa can acclimatize to changing oceanographic environments. These data will have immediate, direct impacts on predictions of reef resilience in a higher carbon dioxide (CO2) world and on the design of reef management strategies.

Extent of CAU deployments and recoveries in the Dry Tortugas in 2015 and 2018. These Islands and atoll are routinely surveyed as part of the Atlantic NCRMP missions.

Lineage Statement:
Assembled CAUs are attached to the benthos using stainless steel threaded rods. Five CAUs are deployed at a survey site. Calcareous organisms, primarily crustose coralline algae and encrusting corals, recruit to these CAUs and accrete/calcify carbonate skeletons over 3 year deployments. Once recovered from the seafloor, the CAUs are processed by the PIFSC Ecosystem Sciences Division to provide estimates of net calcification. CAUs have been deployed and recovered in accordance with protocols developed by Price et al. 2012.

Process Steps:

• 2015-08-01 00:00:00 - CALCIFICATION ACCRETION UNIT (CAU) ASSEMBLY, DEPLOYMENT and RECOVERY CAUs are composed of two 10 x 10 centimeter (cm) flat, square, gray PVC plates, stacked 1 cm apart. Five CAU units are deployed per site on individual stainless steel stakes driven into the substrate. The units are deployed in a clustered group with the spacing between each unit being 0.5 to 5 meters. CAU sites are situated at an average depth of 15 meters. Units are placed so the CAU plates are ~10 cm above the surface substrate and the top of the CAU plate is parallel to the surface of the water. CAU units are recovered from the seafloor 3 years after deployment. Refer to the data files for the individual CAU site to determine the exact deployment time of a specific unit. Refer to the Calcification Accretion Unit (CAU) Assembly, Deployment, and Recovery Standard Operating Procedure (2015) for a detailed description of the protocols. (Citation: Calcification Accretion Unit (CAU) Assembly, Deployment, and Recovery Standard Operating Procedure (2015))
• 2015-09-01 00:00:00 - CALCIFICATION ACCRETION UNIT (CAU) LABORATORY ANALYSIS Once CAU units are recovered they are disassembled and each plate is rinsed with freshwater to remove loose sediment, sand and mobile fauna. The plates are photographed and individual images are captured of the Upper Plate, Top Side; Upper Plate, Bottom Side; Lower Plate, Top Side; Lower Plate, Bottom Side. These images can be analyzed to determine benthic composition on each plate surface. If pieces of calcified material fall off during the photographing process, the pieces are retained with the plate for the dissolution process. After the plates have been photographed they are rinsed with fresh water and placed on a pre-weighed drying plate along with any dislodged pieces, and left to begin drying at room temperature for 24 hours and TO allow excess water to be removed. The drying plate assembly is then placed in the oven to dry at 60 degrees Celsius. If the difference in weights is less than 0.2 grams, the plates are considered dry and no further drying/weighing is required. If the difference in weights is greater than 0.2 grams the drying/reweighing process is repeated for as many 24-hour cycles as needed to obtain a difference of less than 0.2 grams. It should be noted that since the initial sample processing in 2012, the standard weighing protocol has since been improved such that the acceptable weight difference is 0.1 grams. Once the plates are dry, each plate is placed in 5-10% Hydrochloric Acid (HCl) solution to dissolve the calcium carbonate materials. The plate is scraped to remove all materials and rinsed with the dilute HCl solution. The plate is then placed in the oven at 60 degrees Celsius to dry for 24 hours before the dry plate is obtained. Through the entire dissolution process all dilute HCl rinse solution is preserved for later filtering. The dilute HCl rinse process is repeated on all materials removed from the plate until the dissolution process has stopped and all calcium carbonate material has been removed. The fleshy material and used dilute HCl rinse materials are then separated using a vacuum filtration pump by pouring the solution into a Buchner funnel, mesh layer and pre-weighed filter paper. The filter paper and fleshy material are then dried and weighed to determine the weight of fleshy algae present on each plate. The weight of calcified materials on each plate is determined by difference, where the initial weight of the dried plate (prior to the dissolution process) minus the fleshy material weight equals the weight of carbonate material dissolved. The resulting calcification rates are reported in units of grams/area/time. Refer to the Calcification Accretion Unit (CAU) Laboratory Analysis Standard Operating Procedure (2015) for a detailed description of the protocols. (Citation: Calcification Accretion Unit (CAU) Laboratory Analysis Standard Operating Procedure (2015))

Prior to processing a batch from each region/jurisdiction, laboratory analysts inventory the recovered Calcification Accretion Units (CAUs) to ensure all units are accounted for and all serial numbers assigned to each unit match field data records. The Data Manager additionally performs quality control checks on the site deployment data and the recovery data for further accuracy. Once all CAUs from the jurisdiction have been processed, the dataset is checked by the analysts to ensure: 1) all CAU plates have been processed, 2) there are no missing cell values, and 3) calculations for net weight of calcified materials are correct. The dataset is then turned over to the Data Manager for further quality control procedures and data ingestion into the PIFSC Ecosystem Sciences Division master database.

Data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive.

NOAA IRC and NOAA Fisheries ITS resources and assets.