Aggregations of the neustonic hydrozoan Velella velella occur periodically in the northern California Current. Despite the regular occurrence of notable bloom events in this productive upwelling zone, little is known about their trophic ecology. We used gut content and stable isotope analyses (SIA) to elucidate V. velella prey selectivity and...
Pyrosomes are colonial pelagic tunicates that have fascinated marine biologists for over a century. Their name comes from the “fiery” bioluminescence that luminous organs produce at night time. Blooms of pyrosomes, identified as Pyrosoma atlanticum (Peron, 1804), have recently appeared in the North Pacific Ocean, prompting questions about environmental factors...
Mucous-mesh grazers (pelagic tunicates and thecosome pteropods) are common in oceanic waters and efficiently capture, consume and repackage particles many orders of magnitude smaller than themselves. They feed using an adhesive mucous mesh to capture prey particles from ambient seawater. Historically, their grazing process has been characterized as non-selective, depending...
The particle capture mechanisms of biological filters determine the particle spectrum that is ingested by filter-feeding animals. Although ascidian feeding has been extensively investigated, the organismal-scale fluid dynamics and mesh-scale particle-filter interactions are not fully characterized. Fluorescein dye visualization of flow through the branchial sac of the ascidian Ciona intestinalis...
Appendicularians are ubiquitous marine grazers that use tangential filtration to collect micron and submicron prey. The food-concentrating filter (FCF) is the primary determinant of appendicularian prey selectivity, but the precise means by which it concentrates and conveys particles to the pharyngeal filter remain poorly understood. We used high-speed videography to...
Understanding the factors that control predation in pelagic communities can inform predictions of community structure in marine ecosystems. Ubiquitous and selective predators such as cnidarian hydromedusae rely on their nematocysts to capture and retain prey but it is not clear how the density and spatial distribution of these cells relate...