Shifting seagrass-oyster interactions alter species response to ocean warming and acidification

A major challenge in biodiversity research is the incorporation of species interactions into frameworks describing population and community response to global environmental change (GEC). Mutualisms are a type of species interaction especially sensitive to changing environmental conditions, and the breakdown of facilitative species interactions could amplify the negative impacts of novel climate regimes on focal species. Here, we investigate how reciprocal interactions between two coastal foundation species, the eastern oyster (Crassostrea virginica) and eelgrass (Zostera marina) shift in sign and magnitude in response to ocean warming (+1.5C) and acidification (-0.4 pH) via a manipulative co-culture experiment in mesocosms. Under ambient environmental conditions, oysters facilitated eelgrass leaf growth and clonal reproduction by 35% and 38%, respectively. Simultaneously, eelgrass increased oyster condition index (the ratio of tissue to shell biomass) by 35%, indicating greater allocat..., Species Collections and Preparation: We haphazardly collected 600 eelgrass (Zostera marina) ramets (non-reproductive shoots with rhizomes and roots) from a 200 m2 area encompassing the low intertidal and shallow subtidal zones in Brewer Cove, Orr’s Island, ME (43º 47’ 33.5” N, 69º 57’ 14.8’’ W) on June 27th, 2021. Simultaneously, we collected sediment from the adjacent mudflat, which we sieved through 5 mm mesh and homogenized. We standardized eelgrass ramets to one terminal shoot (length ± SD, 90 ± 23 cm) with 3 cm of rhizome and held standardized shoots in a cooler with seawater until planting them in mesocosms on the same day.
We obtained 480 triploid eastern oysters (Crassostrea virginica) from a local oyster aquaculture facility, the Quahog Bay Conservancy, on June 30th, 2021.  Oysters were approximately the same size (mean ± SD, 5.9 ± 2.2 cm2) and drawn at random from hatchery provided bags. We used Gluemasters Industrial Strength Cyanoacrylate Adhesive to attach six oysters equal..., , # Data from: Shifting seagrass-oyster interactions alter species response to ocean warming and acidification

[https://doi.org/10.5061/dryad.gb5mkkx09](https://doi.org/10.5061/dryad.gb5mkkx09)

## Description of the data and file structure

Shifting seagrass-oyster interactions alter species response to ocean warming and acidification, DuBois et al.  Journal of Ecology, 2024.  

### Files and variables

#### File: JEcol0837\_sampling\_log\_meso\_final.csv

**Description:** Data from YSI and bottle sampling on subset of mesocosms to determine pH treatments.

##### Variables

* date: Date and time of sampling
* YSI_temp_C: Temperature in Celsius read by YSI sonde 
* YSI_salinity_psu: Salinity in PSU read by YSI sonde
* YSI_pH: pH read by YSI sonde
* YSI_pH_mV: pH in mV read by YSI sonde
* Bucket_Number: Bucket ID number, 1-60 mesocosms
* Apex.pH: pH read by Apex probe
* TA: TA bottle sample, via titration 
* TA_sd: Standard deviation of TA bottle sample, via titration
* pHp_insitu: pH cal...