Neustonic copepods (Labidocera spp.) discovered living residentially in coral reefs

Abstract

Pontellid copepods are archetypical representatives of the neuston-the highly specialized community living in the top 5-10 cm of the ocean surface. Their deep blue pigmentation and large eyes are unique adaptations to surface irradiation and carnivory, but poor prerequisites for survival in the transparent waters beneath the sea surface. Here, we report the discovery of three reef-associated representatives of this group-Labidocera bataviae A. Scott, 1909; L. pavo Giesbrecht, 1889; and Labidocera sp.-living residential in coral reefs. We (1) document the presence of Labidocera spp. for two separate coral reefs on two expeditions to Papua New Guinea, (2) describe their migration behavior and substrate preference, and (3) quantify the effects of benthic reef community composition on their abundance. All life stages of Labidocera spp. were 43 to 94 times as abundant at the reef sites as in offshore sites. Although pontellids are generally considered non-migrators, Labidocera spp. showed discernible diel vertical migrations: living in reef substrates during the day, emerging into the water column at night (sometimes more than once), and returning to the substrate at dawn. Labidocera spp. showed a pronounced substrate preference for coral rubble, microalgae, and turf, over branching coral, massive boulder coral, and sand.

Nocturnal variation of the zooplankton community in coral reef substrates at Isla del Coco National Park (Eastern Tropical Pacific)

“…More recent studies using traps and other devices have recorded the diel migration pattern over coral reefs (Yahel et al 2005b;Alldredge & King, 2009;Nakajima et al 2009), registering zooplankton abundance peaks at dusk. Recently, Andradi-Brown et al (2017) compared shallow and mesophotic zooplankton communities at Utila island in the Mesoamerican Barrier Reef, and Smith, Richter, Fabricius, and Cornils (2019) described the substrates preferences and migration behavior of Labidocera spp. in two coral reefs systems in Papua New Guinea.…”

Demersal amphipod migrations: spatial patterns in marine shallow waters

“…In this sense, most taxa emerge in greater numbers from complex substrata (e.g. macroalgae, seagrass meadows or corals) than from open sandy areas that offer less shelter from predators or against hydrodynamism (Alldredge & King, 1977; Jacoby & Greenwood, 1988; Rios-Jara, 2005; Smith et al ., 2019). The ability to actively seek for specific refuges when returning to the bottom at dawn determines a spatial segregation of demersal species according to the distribution of different substrates.…”