Copepod manipulation of oil droplet size distribution

8 pages, 3 figures.-- Data are publicly available through the Gulf of Mexico Research Initiative Information & Data Cooperative (GRIIDC) at https://data.gulfresearchinitiative.org (doi: 10.7266/N7H70CV7)Oil spills are one of the most dangerous sources of pollution in aquatic ecosystems. Owing to their pivotal position in the food web, pelagic copepods can provide crucial intermediary transferring oil between trophic levels. In this study we show that the calanoid Paracartia grani can actively modify the size-spectrum of oil droplets. Direct manipulation through the movement of the feeding appendages and egestion work in concert, splitting larger droplets (Ø = 16 µm) into smaller ones (Ø = 4-8 µm). The copepod-driven change in droplet size distribution can increase the availability of oil droplets to organisms feeding on smaller particles, sustaining the transfer of petrochemical compounds among different compartments. These results raise the curtain on complex small-scale interactions which can promote the understanding of oil spills fate in aquatic ecosystemsThis research was made possible by a grant from The Gulf of Mexico Research Initiative. [...] MU was sponsored by the MOKA project (Modelling and Observation of zooplanKtonic orgAnisms; ID: RBFR10VF6M) financed by the Italian Ministry of Education, University and Research, and by SZN internal grant. PH was supported by the Simons Foundation grant “Collaboration on Mathematical Biology” (278436). JM was the financed by the Support for Undergraduate Research Fellows (SURF) and the Center for International Education (CIE), University of Wisconsin-Milwaukee. HJ was supported by NSF grant no. OCE-1433979. MA was funded by the Spanish research project TOPCOP (CTM2011–23480, from the Spanish Ministry of Education and Science, and 2009SGR-1283 from the Catalan Government)Peer Reviewe

Acartia grani and its interactions whit oil droplets

Aquatic Sciences Meeting, Aquatic Sciences: Global And Regional Perspectives - North Meets South, 22-27 February 2015, Granada, SpainFree-swimming Acartia grani and A. clausii were exposed to suspended oil droplets. The oil droplets were created by microfluidic devices using inert mineral oil and had a diameter of 16+/-1 micron. We observed the interactions in experiments on the plankton wheel and visually in a modified Kreisel chamber. We employed high-speed digital video holography focus on the animals during the reconstruction of the holograms. The main result was that populations of 16 micron diameter droplets were chopped up into populations of 4+/-2 micron diameter droplets in addition to the diminishing original population. Such a modification of the size-frequency distribution of the oil droplets enhanced the total surface area per volume of oil. It also lowers the raising speed of the droplet populationPeer Reviewe