A short abstract of the doctoral research

Copepods are small crustaceans present in freshwater and marine habitats. They form a vital link at the basis of marine food webs, feeding on algae and being preyed on by juvenile fish. Pelagic species inhabit the water column while benthic species reside in sediments, rock pools or are associated to seaweeds. The fundamental aspect of this dissertation was aimed at characterizing the microbial environment of benthic copepod guts. A baseline study for lipid composition and population dynamics was conducted for Platychelipus littoralis, as model species for intertidal mudflats. Gut dissections were performed to specifically study the internal microbiome. Ingestion of phosphorescent coated nanobeads by copepods was used to quantify internal oxygen gradients in guts of small copepods.

Copepods have societal value beyond their vital role in the marine food web. They have the ideal size and nutritional composition for juvenile fish and are a preferred live feed in aquaculture. The applied aspect of this dissertation investigated the use of pre- and probiotics during hatching of Acartia tonsa to expand current use of copepods as live feed. Further, Raman spectroscopy was investigated as novel non-invasive technique for lipid quantification in copepods eggs, with potential wider applications in aquaculture.