Temporal variation in pelagic food chain length in response to environmental change


"Climate variability alters nitrogen cycling, primary productivity, and dissolved oxygen concentration in marine ecosystems. We examined the role of this variability (as measured by six variables) on food chain length (FCL) in the California Current (CC) by reconstructing a time series of amino acid–specific δ15N values derived from common dolphins, an apex pelagic predator, and using two FCL proxies.  [...]"

Source: Science Advances
Authors: Rocio I. Ruiz-Cooley et al.
DOI: 10.1126/sciadv.1701140

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Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals


"Little is known about the foraging behavior of top predators in the deep mesopelagic ocean. Elephant seals dive to the deep biota-poor oxygen minimum zone (OMZ) (>800 m depth) despite high diving costs in terms of energy and time, but how they successfully forage in the OMZ remains largely unknown. Assessment of their feeding rate is the key to understanding their foraging behavior, but this has been challenging. Here, we assessed the feeding rate of 14 female northern elephant seals determined by jaw motion events (JME) and dive cycle time to examine how feeding rates varied with dive depth, particularly in the OMZ. [...]"

Source: Ecology and Evolution
Authors: Yasuhiko Naito et al.
DOI: 10.1002/ece3.3202

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