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Vertical distribution and pigmentation of Antarctic zooplankton determined by a blend of UV radiation, predation and food availability

Hylander, Samuel and Hansson, Lars-Anders LU (2013) In Aquatic Ecology 47(4). p.467-480
Abstract
Selection pressure induced by simultaneously occurring environmental threats is a major evolutionary driver for organisms in terrestrial, as well as in aquatic ecosystems. For example, protection against ultraviolet radiation (UVR) and predation include both morphological and behavioral components. Here we address those selective pressures on zooplankton by performing a latitudinal monitoring, combined with mechanistic experiments in the Antarctic Southern Ocean, where the UVR-threat is extremely high. We assessed vertical distributions of zooplankton along the Antarctic coast showing that animals were most abundant at 20-80 m and tended to avoid the surface at sites with clear water. UVR-threat disappeared at between 9 and 15 m at sites... (More)
Selection pressure induced by simultaneously occurring environmental threats is a major evolutionary driver for organisms in terrestrial, as well as in aquatic ecosystems. For example, protection against ultraviolet radiation (UVR) and predation include both morphological and behavioral components. Here we address those selective pressures on zooplankton by performing a latitudinal monitoring, combined with mechanistic experiments in the Antarctic Southern Ocean, where the UVR-threat is extremely high. We assessed vertical distributions of zooplankton along the Antarctic coast showing that animals were most abundant at 20-80 m and tended to avoid the surface at sites with clear water. UVR-threat disappeared at between 9 and 15 m at sites with low and high water transparency, respectively. Light levels were, however, sufficient for visual fish predation down to approximately 19 and 37 m, respectively. The few zooplankton that were present in surface waters had high levels of non-pigmented UVR-protective compounds (mycosporine-like amino acids) compared to deeper dwelling zooplankton. Overall they had low levels of red pigmented UVR-protective compounds (carotenoids), suggesting high predation on pigmented individuals. In a complementary laboratory study we showed that levels of UVR-protective compounds increased considerably when zooplankton were exposed to UVR in the absence of predator cues. The recently developed transparency-regulator hypothesis predicts that UVR avoidance is an important driver to diel vertical migration in transparent waters, such as in Antarctica. We, however, conclude that copepods resided well below the level where UVR had diminished to very low levels and that predator avoidance or food availability are more likely drivers of zooplankton vertical depth distribution in transparent marine systems. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Zooplankton, Ecology, Vertical distribution, Carotenoids, MAAs, Ultraviolet radiation, Antarctica, Diel vertical migration
in
Aquatic Ecology
volume
47
issue
4
pages
467 - 480
publisher
Springer
external identifiers
  • wos:000327070200009
  • scopus:84887932601
ISSN
1386-2588
DOI
10.1007/s10452-013-9459-7
language
English
LU publication?
yes
id
124d41f7-d511-40b3-93d8-fdcb5dd1338b (old id 4273296)
date added to LUP
2014-01-30 15:50:35
date last changed
2019-07-02 02:39:19
@article{124d41f7-d511-40b3-93d8-fdcb5dd1338b,
  abstract     = {Selection pressure induced by simultaneously occurring environmental threats is a major evolutionary driver for organisms in terrestrial, as well as in aquatic ecosystems. For example, protection against ultraviolet radiation (UVR) and predation include both morphological and behavioral components. Here we address those selective pressures on zooplankton by performing a latitudinal monitoring, combined with mechanistic experiments in the Antarctic Southern Ocean, where the UVR-threat is extremely high. We assessed vertical distributions of zooplankton along the Antarctic coast showing that animals were most abundant at 20-80 m and tended to avoid the surface at sites with clear water. UVR-threat disappeared at between 9 and 15 m at sites with low and high water transparency, respectively. Light levels were, however, sufficient for visual fish predation down to approximately 19 and 37 m, respectively. The few zooplankton that were present in surface waters had high levels of non-pigmented UVR-protective compounds (mycosporine-like amino acids) compared to deeper dwelling zooplankton. Overall they had low levels of red pigmented UVR-protective compounds (carotenoids), suggesting high predation on pigmented individuals. In a complementary laboratory study we showed that levels of UVR-protective compounds increased considerably when zooplankton were exposed to UVR in the absence of predator cues. The recently developed transparency-regulator hypothesis predicts that UVR avoidance is an important driver to diel vertical migration in transparent waters, such as in Antarctica. We, however, conclude that copepods resided well below the level where UVR had diminished to very low levels and that predator avoidance or food availability are more likely drivers of zooplankton vertical depth distribution in transparent marine systems.},
  author       = {Hylander, Samuel and Hansson, Lars-Anders},
  issn         = {1386-2588},
  keyword      = {Zooplankton,Ecology,Vertical distribution,Carotenoids,MAAs,Ultraviolet radiation,Antarctica,Diel vertical migration},
  language     = {eng},
  number       = {4},
  pages        = {467--480},
  publisher    = {Springer},
  series       = {Aquatic Ecology},
  title        = {Vertical distribution and pigmentation of Antarctic zooplankton determined by a blend of UV radiation, predation and food availability},
  url          = {http://dx.doi.org/10.1007/s10452-013-9459-7},
  volume       = {47},
  year         = {2013},
}