Zooplankton Distribution and Community Structure in the Pacific and Atlantic Sectors of the Southern Ocean during Austral Summer 2017–18: A Pilot Study Conducted from Ukrainian Long-Liners

Abstract

<jats:p>Preliminary results of the pilot study of the zooplankton in the region between the Ross and Scotia Seas from November 2017 to April 2018 are presented. In total, 53 zooplankton samples were collected in the top 100 m water layer using vertical tows of a 0.1 m2 Juday net from four Ukrainian longliners operating during the Antarctic toothfish fishery. Total zooplankton abundance ranged from 3 to 2836 ind m−3 with a global mean of 360 ± 550 (±1 SD) ind m−3. The highest abundances were recorded at the northeastern Ross Sea. At those stations, small copepods (mainly Oithona spp., Oncaea spp., Ctenocalanus spp. and copepod nauplii) numerically dominated the samples. Total biomass ranged from 0.3 to 85 mg DW m−3 with a mean of 10.9 ± 14.5 mg DW m−3. The highest biomasses were recorded at the eastern Ross Sea, where pelagic tunicates Salpa thompsoni, siphonophores and ctenophora Callianira sp. accounted for &gt;90% of total zooplankton biomass. At other stations, zooplankton biomass generally ranged from 5 to 20 mg DW m−3 with no clear pattern in distribution. The community composition was driven by the sampling latitude and/or season rather than longitudinally. This pilot study emphasized the unique opportunity to investigate zooplankton dynamics in the regions traditionally not sampled during the oceanographic surveys. It also created unprecedented opportunities to increase the seasonal and geographical zooplankton sampling coverage using ships of opportunity at a fraction of a dedicated oceanographic survey costs. The potential of such surveys are enormous in both providing invaluable information, contributing to existing long-term databases and enhancing an international collaboration in the Southern Ocean, particularly in light of recent modeling initiatives of the whole Antarctic system undertaken by the Commission for the Conservation of Antarctic Marine Living Resources.</jats:p>

Copepod community from Arctic to Antarctic

“…Here, nauplii were represented with a minimal value found, while conversely KRŠINIĆ (2018) found relatively large abundances of tintinnids during the same cruise. The most probable reason for the absence of postnaupliar copepods in the Scotia Sea sample is the patchiness of zooplankton and small diameter of the plankton net, since there is an extensive literature documenting the diversity and abundance of calanoids and cyclopoids in this region (WARD & HIRST, 2007;CORNILS et al, 2018;PAKHOMOV et al, 2020).…”

“…Nowadays, oceanographic expeditions covering the world's oceans from pole to pole have become extremely rare and, due to the enormous financial requirements, are only possible for relatively few research institutions. Therefore, the use of citizen science and opportunity sampling during commercial or tourist voyages can provide valuable plankton material from less visited or little explored sites over wide geographic areas (PAKHOMOV et al, 2020). One such opportunity occurred during the Arctic-Antarctic cruise aboard the S/V "Croatian Tern," a 19.8 m steel ketch built in a Croatian shipyard.…”

Submarine Tailings in Chile—A Review

“…The pelagic ecosystem consists of all the organisms that inhabit the middle waters of the oceans and seas. The species in this area are fish, phytoplankton, zooplankton, and predators [48][49][50]. The disposal of tailings in the sea has a more significant impact on the benthic fauna because they directly contact the seabed.…”

The Global Distribution and Drivers of Grazing Dynamics Estimated from Inverse Modelling

“…Unfortunately, unlike chlorophyll and phytoplankton biomass, which can be inferred from ocean optical properties measured remotely , zooplankton biomass cannot be measured from satellites. Instead, zooplankton must be measured at sea using a variety of di↵erent methods (Pakhomov et al, 2020;Pinkerton et al, 2020;Benfield et al, 1998), each with large uncertainties and disparate units (Moriarty et al, 2013), making it di cult to describe the global distribution without large levels of statistical inference (Everett, n.d.;Heneghan et al, 2020).…”