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Bioaccumulation of Trace Elements in Myctophids in the Oxygen Minimum Zone Ecosystem of the Gulf of California

Abstract.

"Myctophids are key members of mesopelagic communities with a world biomass estimated at 600 million tons. They play a central role in oceanic food webs and are known to perform diel vertical migrations, crossing the thermocline and reaching the oxygen minimum zone, however, very scarce information exists on trace element content in these organisms. Therefore, the trace elemental composition (Cr, Mn, Co, Ni, Cu, Zn, As, Se, Cd and Pb) of Triphoturus mexicanus and Benthosema panamense specimens was determined. Zinc (Zn) was the most common trace element for both species, T. mexicanus presented 39.8 µg.g−1 dw and B. panamense 30.6 µg.g−1 dw. [...]"

Source: Oceans
Authors: Cátia Figueiredo et al.
DOI: 10.3390/oceans1010004

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The regulation of oxygen to low concentrations in marineoxygen-minimum zones

Abstract.

"The Bay of Bengal hosts persistent, measurable, but sub-micromolar, concentrations of oxygenin its oxygen-minimum zone (OMZ). Such low-oxygen conditions are not necessarily rare in theglobal ocean and seem also to characterize the OMZ of the Pescadero Basin in the Gulf of California,as well as the outer edges of otherwise anoxic OMZs, such as can be found, for example, in theEastern Tropical North Pacific. We show here that biological controls on oxygen consumption arerequired to allow the semistable persistence of low-oxygen conditions in OMZ settings; otherwise,only small changes in physical mixing or rates of primary production would drive the OMZ betweenanoxic and oxic states with potentially large swings in oxygen concentration. [...]"

Source: Journal of Marine Research
Authors: Donald E. Canfield et al.
 

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Home sweet suboxic home: remarkable hypoxia tolerance in two demersal fish species in the Gulf of California

"Extremophiles – organisms that live in extreme environments – invite us to question our assumptions about the requirements for life. Fish, as a group, are thought to be relatively hypoxia intolerant due to their high metabolic requirements (Vaquer‐Sunyer and Duarte 2008); however, the cusk‐eel, Cherublemma emmelas, and the catshark, Cephalurus cephalus, appear to thrive in one of the most extreme low oxygen marine habitats in the world – the Gulf of California. Here, we describe the behavior and habitat of these extraordinary species that live under conditions commonly thought to be uninhabitable by fish. [...]"

Source: Ecology
Authors: Natalya D. Gallo et al.
DOI: 10.1002/ecy.2539

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