As you may have seen in previous posts, marine snow (misc. detritus) has been a major theme of KM2414 as a phytoplankton bloom is deteriorating. We have been deploying a towed plankton imaging system, the Video Plankton Recorder (VPR, below). This instrument works by taking images of small particles that are typically millimeters in size (200um-cm).
Of relevance to this post is that this instrument can take images of marine snow (below, as a collage of 4 images). Marine snow is mostly dead material, slowly sinking out of the water column. The PICA took a fabulous video of the snow-like effect of the sinking detritus. With the VPR, we can see that the fluffy looking particles are highly diverse and composed of different things. The upper left image is highly compact, perhaps from multiple smaller particles lumping together. The upper right has a couple of separate clumps that are only linked loosely. The bottom left is even more loosely clumped. Finally, the bottom right is the most diffuse, with several rod like structures (diatoms). The diatom chains in the bottom right image may still be alive and photosynthesizing.
We have seen an incredible number of marine snow images in the water as a result of the bloom, but marine snow can be observed anywhere in the ocean. Particles such as these form the basis of export of surface productivity into the deep ocean, where it is then used by deep sea organisms or sinks to the seafloor. Of course, surface organisms are also able to take advantage of marine snow, like the Acantharian below.
