Questioning the Rise of Gelatinous Zooplankton in the World's Oceans

Abstract

miCHael n daWson, maRy betH deCKeR, Claudia e. mills, JennifeR e. PuRCell, alenKa maleJ, HeRmes mianzan, sHin-iCHi uye, stefan GelCiCH, and lauRenCe P. madin During the past several decades, high numbers of gelatinous zooplankton species have been reported in many estuarine and coastal ecosystems. Coupled with media-driven public perception, a paradigm has evolved in which the global ocean ecosystems are thought to be heading toward being dominated by "nuisance" jellyfish. We question this current paradigm by presenting a broad overview of gelatinous zooplankton in a historical context to develop the hypothesis that population changes reflect the human-mediated alteration of global ocean ecosystems. To this end, we synthesize information related to the evolutionary context of contemporary gelatinous zooplankton blooms, the human frame of reference for changes in gelatinous zooplankton populations, and whether sufficient data are available to have established the paradigm. We conclude that the current paradigm in which it is believed that there has been a global increase in gelatinous zooplankton is unsubstantiated, and we develop a strategy for addressing the critical questions about long-term, human-related changes in the sea as they relate to gelatinous zooplankton blooms.

qPCR Detection of Early Life History StageChrysaora quinquecirrha(Sea Nettles) in Barnegat Bay, New Jersey

“…A lack of long-term data regarding jellyfish blooms makes understanding the large, and seemingly increasing, populations of jellyfish difficult to assess (Condon et al, 2012). Underwater cameras, acoustic monitoring, and blue-water diving are all methods that can be used to detect the presence and abundance of jellyfish (Condon et al, 2012).…”

“…Underwater cameras, acoustic monitoring, and blue-water diving are all methods that can be used to detect the presence and abundance of jellyfish (Condon et al, 2012). This study presents a sensitive, real-time qPCR method that can successfully and accurately determine the presence and relative abundance of C. quinquecirrha eDNA in water samples from Barnegat Bay.…”

“…However, the paucity of earlier research on C. quinquecirrha makes evaluating and understanding these blooms difficult. Many other marine and estuary systems have also experienced more frequent and larger blooms of scyphozoans and other gelatinous zooplankton (Condon et al, 2012;Hoover and Purcell, 2009). This makes it increasingly important to study and understand how these organisms are able to adapt and dominate in estuarine systems and the environmental factors contributing to the success of C. quinquecirrha.…”

Massive salp outbreaks in the inner sea of Chiloe Island (Southern Chile): possible causes and ecological consequences

“…It seems that human alterations to major ecosystems, which in turn have caused jelly outbreaks, are behind planktonic ecosystem shifts, and some anticipate that this will worsen in the future (Richardson et al, 2009). Meanwhile, a recent review (Condon et al, 2012) brings some caution to these findings based on the little knowledge of the historical ecosystem baseline for almost all jelly plankton species. The lack of historical background, the inaccuracy of the plankton nets used and sporadic sampling efforts is the main drawback to solve the paradigm of the abundance of these groups.…”

Marine ecology: Attack of the blobs

“…This week, a group of researchers published preliminary results from what will be the most comprehensive review of jellyfish population data 1 . They say that there is not yet enough evidence to support any conclusions about a global upswing in jellyfish populations.…”