We report the results of a series of experiments investigating the combined effects of ocean acidification and suspended natural benthic sediments (NS) generated during bottom trawling on the early life stages of the cold-water coral Desmophyllum pertusum (syn. Lophelia pertusa). The experiment was conducted at the Tjärnö Marine Laboratory Facilities (University of Gothenburg, Sweden). For each experiment, the larvae/embryos were exposed to four different treatments: (1) current pCO2 (control): mimicking present-day pCO2/pH condition (pCO2 400 µatm; ambient pHT: 8.01), (2) high pCO2: a scenario reflecting the IPCC RCP8.5 prediction (pCO2 1000 µatm; low pHT: 7.63), (3) current pCO2 + NS (5 mg/L), and (4) high pCO2 + NS (5 mg/L): with the introduction of natural benthic sediments (NS) at a concentration of 5 mg/mL. The NS were collected at ~130 m water depth from a regularly trawled soft bottom close to the reef site of Säcken in the Northern Koster-fjord in Sweden, and the grain sizes ≤ 63 μm were used for the experiment. Embryos and larvae were exposed to the different treatments in 75 mL culture flasks mounted on a rotating plankton wheel to keep sediments in suspension. The second experiment examined the effects on larval survival and swimming speed in two sub-experiments: A) short-term exposure (48 hours) and B) long-term exposure (1 week). This dataset presents the results for larval swimming speeds under short-term exposure.

Number of larvae or embryos used for the experiments: 30-35 larvae or embryos per replicateIf the Individual ID column is present, each observation corresponds to one larvae.Condition is based on the percentage of abnormalities. If greater than 50%, the condition is considered as bad; otherwise, it is considered as good.