Guest essay by Eric Worrall
Journalists and several scientists who noticed a few recent jellyfish blooms have leapt to their catch all explanation.
Jellyfish are causing mayhem as pollution, climate change see numbers boom
RN By Hong Jiang and Sasha Fegan for Late Night Live
Updated yesterday at 12:16pm
Jellyfish have been around for at least 500 million years — they’re older than dinosaurs and even trees.
Science writer Juli Berwald calls them “ghosts from the true garden of Eden”.
“An intelligence of a sort has allowed them to make it through the millennia,” she says.
And they’re not going anywhere.
In fact, the brainless, spineless, eyeless, bloodless creatures are booming in numbers — and causing mayhem around the world.
A human cause
Some scientists think jellyfish numbers are increasing as the climate changes — the creatures reproduce well in warmer waters.
Jellyfish also fare better than many other sea creatures in polluted waters, as they don’t need much oxygen.
Berwald says that can give them the upper hand over predators.
“They can sort of slip into polluted waters, into low oxygen waters, and hide from predation there better than a fish that has a higher oxygen demand,” she says.
Just one problem with this story; Jellyfish blooms have been occurring since the Cambrian Period, with plenty of evidence of Jellyfish blooms in the fossil record, let alone modern times (see the image at the top of the page).
From a study in 2012 by the American Institute of Biological Sciences;
Questioning the Rise of Gelatinous Zooplankton in the World’s Oceans
RobeRt H. Condon, William m. GRaHam, CaRlos m. duaRte, Kylie a. Pitt, CatHy H. luCas, steven H.d. HaddoCK, Kelly R. sutHeRland, Kelly l. Robinson, 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 his- torical 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.
Gelatinous zooplankton blooms have ancient origins and are not a new phenomenon. Following a call for further studies of the role of fishes and jellyfishes and their possible role in maintaining the natural ecology of the sea (Parsons 1993), Mills (1995) suggested that the jellyfish, which are ubiquitous in nearly all marine ecosystems, may be positioned to increase in areas that have been subjected to overharvesting and environmental perturbations.
In a number of recent review articles, potential drivers have been discussed that might lead to increases of gelatinous zooplankton (e.g., Mills 2001, Purcell et al. 2007, Richardson et al. 2009). Richardson and colleagues (2009) concluded that the rise in the numbers of jellyfish and salps is both a symptom and a necessary and unavoidable outcome of the cumulative human impacts that have caused a deterioration of the ocean ecosystem. A closer examination of these articles, however, reveals that the data necessary to test such statements are unavailable, which is even acknowledged in the articles. Indeed, most statements about an increased number of jellyfish blooms are based on local and sometimes regional studies, which are often focused on only a few well-studied (e.g., Aurelia spp.), high-visibility (e.g., Nemopilema nomurai), or invasive (e.g., M. leidyi) species, and a global analysis has not yet been attempted. Given the dearth of knowledge about gelatinous zooplankton in major ocean basins, do these studies truly represent the entire range of fluctuations exhibited globally by mod- ern populations? Moreover, some of the regions that provide the strongest evidence that jellyfishes were rising in number (e.g., Bering Sea; Brodeur et al. 1999, 2008) exhibited subsequent declines, leading to the conclusion that the apparent increasing trends were probably part of low-frequency oscillations driven by natural climatic cycles that may cause large-scale regime shifts in the ocean (box S1, Purcell et al. 2007, Brodeur et al. 2008).
What a surprise – the climate jellyfish apocalypse is the product of speculation and inadequate data.