Marine Biology


Animal and Veterinary Science


Prada, Carlos

Advisor Department

Biological Sciences




Gelatinous Zooplankton, Sea Surface Temperature, Climate Change

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License.


Anna Byczynski (Marine Biology)

Sponsor: Carlos Prada (Biology Sciences)

Gelatinous Zooplankton Response to Interannual Variation in Sea Surface Temperature in New Zealand

Temperature, nitrogen, and dissolved oxygen are key factors that sustain marine life and at the same time are changing rapidly due to human driven environmental change. Gelatinous zooplankton, comprising of medusa, ctenophores, salps, and siphonophores, are organisms responding rapidly to these changing environmental conditions. Their simple body organization and physiology allow them to experience directly the external environment, and thus are ideal organisms to understand how environmental variation due to human activities including climate change affect marine communities. To understand variation in gelatinous zooplankton abundance and assemblage across gradients of temperature, dissolved oxygen, and nitrogen I sampled surface seawater with a CTD carousel, neuston tows, and bucket sampling. This was done aboard Sea Education Association’s research vessel, SSV Robert C. Seamans, along the east coast of the North and South Islands of New Zealand. I found that there is a bimodal distribution in gelatinous zooplankton abundance between 20-23 °C, with a maximum of eighty percent of the total count found within this range. Gelatinous zooplankton was found at a low nitrate level (0.1μM) and gelatinous zooplankton concentrations peaked between 180 and 200 µmol/kg of dissolved oxygen. For the second half of my Honors Project I further examined the effect of variable sea surface temperature on gelatinous zooplankton abundance and assemblage. I compiled data from other cruises aboard the Seamans from 2015 to 2019 around New Zealand. The results show that temperature increased in the North region, and stayed relatively stable in the Mid and South region. Overall, the North region was the warmest with decreasing mean temperature in the Mid and then South region respectively. Gelatinous Zooplankton trends showed varying degrees of abundances within the different temperature zones and salps were highest in the assemblage type. Understanding how increasing sea surface temperature has changed the dynamics of gelatinous zooplankton in New Zealand is paramount to understanding the ecosystems in the euphotic zone on which these organisms are major players.