Blue pigmentation of neustonic copepods benefits exploitation of a prey-rich niche at the air-sea boundary

Abstract

The sea-surface microlayer (SML) at the air-sea interface is a distinct, under-studied habitat compared to the subsurface and copepods, important components of ocean food webs, have developed key adaptations to exploit this niche. By using automated SML sampling, high-throughput sequencing and unmanned aerial vehicles, we report on the distribution and abundance of pontellid copepods in relation to the unique biophysicochemical signature of the SML. We found copepods in the SML even during high exposure to sun-derived ultraviolet radiation and their abundance was significantly correlated to increased algal biomass. We additionally investigated the significance of the pontellids’ blue pigmentation and found that the reflectance peak of the blue pigment matched the water-leaving spectral radiance of the ocean surface. This feature could reduce high visibility at the air-sea boundary and potentially provide camouflage of copepods from their predators.

Enhanced Viral Activity in the Surface Microlayer of the Arctic and Antarctic Oceans

“…The assessed SML temperature in the Arctic registered slightly but significantly higher values in the SML than in the SSW. Although we have to take these values with caution due to technical limitations and the evidence from other studies showing that temperature tends to be lower in the SML than in the SSW [ 46 ], the significant correlation between temperature and viral abundance only in the SML ( r = 0.436, p < 0.05, Table S1 ) suggests that increasing temperatures would contribute to the increase in viral abundance [ 47 ].…”

The Virioneuston: A Review on Viral–Bacterial Associations at Air–Water Interfaces

“…This aspect deserves further investigation, as many mesozooplankton species frequently populate the SML [ 4 , 93 ] and hence represent appropriate bacterial and viral targets. Zooplankton species that occasionally migrate to the SML during diel vertical migration or for feeding purposes [ 28 ] might also serve as important vectors for viruses that infect bacteria or phytoplankton living therein [ 94 ] ( Figure 1 ).…”

“…However, some exceptions of photosynthetic organisms, e.g., Trichodesmium, Synechococcus , or Sargassum, show more tolerance towards high light intensities and, hence, can become enriched in the SML [ 4 , 19 , 20 ]. Previous research has provided evidence that neustonic organisms can cope with wind and wave energy [ 12 , 21 , 22 ], solar and ultraviolet (UV) radiation [ 23 , 24 , 25 ], fluctuations in temperature and salinity [ 26 , 27 ], and a higher potential predation risk by the zooneuston [ 28 ]. Furthermore, wind action promoting sea spray formation and bubbles rising from deeper water and bursting at the surface release SML-associated microbes into the atmosphere [ 29 ].…”

Using Ship-Deployed High-Endurance Unmanned Aerial Vehicles for the Study of Ocean Surface and Atmospheric Boundary Layer Processes

“…Figure 3 shows a map of the focus region north of Papua New Guinea and several UAV flight missions, including one flight track coded with surface brightness temperature. These operations demonstrated the utility of the ship-deployed UAVs using the HQ-60 from the R/V Falkor (Rahlff et al, 2018;Wurl et al, 2018). We demonstrated the impact of scientific UAV usage extends into the realm of upper-ocean biological processes.…”

“…These systems have been well tested by LDEO with over 50 total flights and over 150 total flight hours. We have demonstrated the utility of the HQ systems as ship-deployed platforms on the R/V Falkor in October-November 2016 between Australia and Guam (Rahlff et al, 2018;Wurl et al, 2018) and have recently deployed them in the field in Kotzebue Alaska in April-May 2018 and 2019.…”