Potential Polyunsaturated Aldehydes in the Strait of Gibraltar under Two Tidal Regimes

Abstract

Diatoms, a major component of the large-sized phytoplankton, are able to produce and release polyunsaturated aldehydes after cell disruption (potential PUAs or pPUA). These organisms are dominant in the large phytoplankton fraction (>10 µm) in the Strait of Gibraltar, the only connection between the Mediterranean Sea and the Atlantic Ocean. In this area, the hydrodynamics exerts a strong control on the composition and physiological state of the phytoplankton. This environment offers a great opportunity to analyze and compare the little known distribution of larger sized PUA producers in nature and, moreover, to study how environmental variables could affect the ranges and potential distribution of these compounds. Our results showed that, at both tidal regimes studied (Spring and Neap tides), diatoms in the Strait of Gibraltar are able to produce three aldehydes: Heptadienal, Octadienal and Decadienal, with a significant dominance of Decadienal production. The PUA released by mechanical cell disruption of large-sized collected cells (pPUA) ranged from 0.01 to 12.3 pmol from cells in 1 L, and from 0.1 to 9.8 fmol cell−1. Tidal regime affected the abundance, distribution and the level of physiological stress of diatoms in the Strait. During Spring tides, diatoms were more abundant, usually grouped nearer the coastal basin and showed less physiological stress than during Neap tides. Our results suggest a significant general increase in the pPUA productivity with increasing physiological stress for the cell also significantly associated to low nitrate availability.

Diatom‐produced allelochemicals trigger trophic cascades in the planktonic food web

“…Although there is no other published information on PUA in the Chesapeake Bay and the Virginia coastal waters, Skeletonema is common in both ecosystems and occasionally forms blooms. For comparison, in the Strait of Gibraltar (Morillo‐Garcia et al ) and the offshore Atlantic Ocean waters (Bartual et al ), PUA concentrations were in the pico‐molar range under no‐bloom conditions.…”

Viability of pico- and nanophytoplankton in the Baltic Sea during spring

“…For example polyunsaturated aldehydes (PUAs) produced by marine diatoms reduce growth and viability among other phytoplankton species (Casotti et al 2005;Ribalet et al 2007Ribalet et al , 2014. Recently, it has been shown that also some nanoand picoplankton taxa produce PUAs (Vidoudez et al 2011a;Morillo-García et al 2014).…”

Diatom-Derived Polyunsaturated Aldehydes Are Unlikely to Influence the Microbiota Composition of Laboratory-Cultured Diatoms

“…With renewed interest in elucidating the role of PUA at sea, particularly over oceanic scales [20,27,[35][36][37][38][39], it is timely to revisit the bacteriostatic hypothesis, albeit at a laboratory scale. We used next-generation sequencing to address the biodiversity element of the bacteriostatic definition.…”