Influences of mesoscale anticyclonic eddies on the zooplankton community south of the western Aleutian Islands during the summer of 2010

Abstract

Mesoscale anticyclonic eddies have been observed south of the Aleutian Islands. Eddies farther east, in the Gulf of Alaska, are known to transport coastal water and coastal zooplankton to the offshore open ocean. The impacts of mesoscale anticyclonic eddies formed south of the western Aleutian Islands (Aleutian eddies) on the zooplankton community are not fully understood. In the present study, we describe zooplankton population structures within an Aleutian eddy and outside the eddy during July 2010. Based on the sea-level anomaly, the Aleutian eddy was formed south of Attu Island (172854 0 E) in February 2010, and it moved southeastward in the next 5 months. Large oceanic copepods, Neocalanus cristatus, Eucalanus bungii and Metridia pacifica were more abundant inside the eddy than the outside. Inside the eddy, the life stage distribution of N. cristatus was more advanced than that outside, and Neocalanus spp. had accumulated more lipids. These conditions probably reflect the greater primary production in the eddy, production enhanced by nutrients

Mesoscale Eddy-Induced Ocean Dynamic and Thermodynamic Anomalies in the North Pacific

“…The trajectories of eddies longer than 180 days are shown in Figure 1C, which reveals that eddies travel longer (shorter) distances near the equator (at higher latitudes), as a result of the poleward decreasing Rossby wave speed. Eddies in the subarctic North Pacific (in the Gulf of Alaska and along the Aleutian Islands) are long-living and quasi-stationary, exhibiting the shortest travel distance (Di Lorenzo et al, 2005;Rogachev et al, 2007;Saito et al, 2014;Shlyk, 2018, 2019). Active eddy generation is noticeable along the eastern boundary, where coastal Kelvin waves from the tropics are transformed into Rossby waves propagating westward away from the boundary (Clarke and Shi, 1991;Fu and Qiu, 2002).…”

“…The pattern of explained SSH variability resembles the pattern of absolute mean eddy amplitude (Figure 1D), except that in the less pronounced eddy active regions than the KE (e.g., the STCC), the weaker eddies do explain a large fraction of total variability. Eddy contribution then decays toward sub-seasonal and longer scales except for some spots along the Kuroshio and in the Gulf of Alaska (Figure 10, left column), respectively, associated with the large meanders of the former (Sugimoto and Hanawa, 2012;Usui et al, 2013) and the quasi-permanent eddies in the latter (Di Lorenzo et al, 2005;Saito et al, 2014).…”

On the Errors of Estimating Oceanic Eddy Kinetic Energy

“…For the latter two kinds of eddies, which correspond to the mesoscale and (quasi‐) permanent eddies, the MREE highlights the central and eastern parts of the ocean basins as opposed to the more energetic western boundary currents such as the Kuroshio and Gulf Stream, where MREE is on the order of 5%–10%. In Figure 12p, for instance, the generation and westward propagation of Rossby waves and the Gulf of Alaska eddies, i.e., the Haida, Sitka, Yakutat, and Kenai eddies (e.g., Di Lorenzo et al., 2005; Saito et al., 2014) from the Pacific North American coast, as well as the Alaskan Stream eddies and Aleutian eddies along the coast of Alaska and the Aleutian Islands (Rogachev et al., 2007; Rogachev & Shlyk, 2018, 2019; Saito et al., 2014), are easily detectable. These eddies are all on interannual timescales.…”

Aleutian Eddies and Their Impact on Temperature and Dissolved Oxygen in the Western Subarctic Pacific

“…с дрейфом алеутских вихрей. Используя экспедиционные данные, собранные летом 2010 г. и летом 2012 г., исследователи (Saito et al, 2014(Saito et al, , 2016 описали структуру вод алеутских вихрей и представили распределения зоопланктона в зоне алеутских вихрей. В данной статье основное внимание уделено алеутским вихрям, формирующимся к югу от островов Ближние в зоне 50-52°с.ш., 171-174°в.д.…”