Data from: Vertical distribution of marine invertebrate larvae in response to thermal stratification in the laboratory
Daigle, Rémi M.; Metaxas, Anna (2013), Data from: Vertical distribution of marine invertebrate larvae in response to thermal stratification in the laboratory, Dryad, Dataset, https://doi.org/10.5061/dryad.61f07
We investigated the effect of the presence of an experimentally generated thermocline on the vertical distribution of larval Strongylocentrotus droebachiensis, Asterias rubens and Argopecten irradians. Vertical distributions were recorded over 90 min in rectangular plexiglass thermocline chambers designed to regulate the temperature of a central observation compartment to the desired values. The temperature in the bottom water layer (B) and the temperature difference between layers (ΔT) were manipulated in an orthogonal design. We used, for S. droebachiensis: 4 levels of ΔT (0, 3, 6 and 12 °C) and 3 levels of B (3, 6 and 9 °C); for A. rubens: 3 levels ΔT (0, 6 and 12 °C) and 2 levels of B (6 and 12 °C); and for A. irradians: 3 levels of ΔT (0, 5 and 11 °C) and 2 levels of B (5 and 11 °C). The difference in temperature between water layers did not affect the vertical distribution of echinoderms consistently, while the distribution of A. irradians was limited to the bottom layer when any thermal stratification was present regardless of strength. Our results suggest that the vertical position of larvae of S. droebachiensis and A. rubens is related to the temperatures of the surface layer and that the presence alone or the steepness of the thermocline has less influence on their distribution. Consequently, in the field, echinoderm larvae would aggregate at the surface unless temperature extremes were encountered. In contrast, the position of A. irradians was limited to the bottom layer in the presence of a thermocline of at least 5 °C (the shallowest used in our study). Such thermoclines are common in a natural setting and could affect the vertical distribution and horizontal dispersal of larvae by acting as a barrier to vertical migration.