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

Cátia Figueiredo,Tiago Grilo,Joana Raimundo,Rui Rosa,Unai Markaida,Miguel Caetano,Miguel Baptista

doi:10.3390/oceans1010004

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. Contrasting, for T. mexicanus the less abundant trace element was Ni (0.332 µg.g−1 dw) and for B. panamense was Pb (0.236 µg.g−1 dw). T. mexicanus exhibited significantly higher concentrations of Cr, Cu, Zn and Pb in comparison to B. panamense, and these differences seemed to be related to inherent physiological and/or ecological traits rather than environmental element availability. These diel vertical migrators are crucial in the energy transfer between the deep-sea and epipelagic zones (and vice-versa), and the estimation of the Biomagnification Factor (based on Cu, Zn, Cd and Pb) levels revealed that both T. mexicanus and B. panamense play a major role in trace element transfer to higher trophic levels in the pelagic food web of the Gulf of California.

Highlights

Myctophids, known as lanternfish, are the most widespread and diverse mesopelagic fish taxa with approximately 250 species distributed among 33 genera [1]
The dataon presented arebioaccumulation comparable to those obtained for is other myctophid the data are comparable to those obtained for other myctophid species, species, with thepresented exception of
We argue that the myctophids’ diet composition in GC plays a key role in the low accumulation of As, since it has a nutrient-like behavior and food intake is the main source of As in marine organisms [56]

Summary

Introduction

Myctophids, known as lanternfish, are the most widespread and diverse mesopelagic fish taxa with approximately 250 species distributed among 33 genera [1]. These small fish (2–15 cm, total length) account for as much as 65% of all deep-sea fish biomass, with an estimated global biomass of 600 million tons [2,3]. Myctophids constitute a major component of the deep scattering layer (DSL), a sound scattering layer in the water column. Enough light is available for major component of the deep scattering layer (DSL), a sound scattering layer in the water column photosynthesis

Results

Discussion

Conclusion