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| Titel |
Effect of hypoxia and anoxia on invertebrate behaviour: ecological perspectives from species to community level |
| VerfasserIn |
B. Riedel, T. Pados, K. Pretterebner, L. Schiemer, A. Steckbauer, A. Haselmair, M. Zuschin, M. Stachowitsch |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 6 ; Nr. 11, no. 6 (2014-03-21), S.1491-1518 |
| Datensatznummer |
250117302
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| Publikation (Nr.) |
 copernicus.org/bg-11-1491-2014.pdf |
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| Zusammenfassung |
| Coastal hypoxia and anoxia have become a global key stressor to marine
ecosystems, with almost 500 dead zones recorded worldwide. By triggering
cascading effects from the individual organism to the community- and
ecosystem level, oxygen depletions threaten marine biodiversity and can alter
ecosystem structure and function. By integrating both physiological function
and ecological processes, animal behaviour is ideal for assessing the stress
state of benthic macrofauna to low dissolved oxygen. The initial response of
organisms can serve as an early warning signal, while the successive
behavioural reactions of key species indicate hypoxia levels and help assess
community degradation. Here we document the behavioural responses of a
representative spectrum of benthic macrofauna in the natural setting in the
Northern Adriatic Sea (Mediterranean). We experimentally induced small-scale
anoxia with a benthic chamber in 24 m depth to overcome the difficulties in
predicting the onset of hypoxia, which often hinders full documentation in
the field. The behavioural reactions were documented with a time-lapse
camera. Oxygen depletion elicited significant and repeatable changes in
general (visibility, locomotion, body movement and posture, location) and
species-specific reactions in virtually all organisms (302 individuals from
32 species and 2 species groups). Most atypical (stress) behaviours were
associated with specific oxygen thresholds: arm-tipping in the ophiuroid
Ophiothrix quinquemaculata, for example, with the onset of mild
hypoxia (< 2 mL O2 L−1), the emergence of polychaetes on the
sediment surface with moderate hypoxia (< 1 mL O2 L−1), the
emergence of the infaunal sea urchin Schizaster canaliferus on the
sediment with severe hypoxia (< 0.5 mL O2 L−1) and heavy body
rotations in sea anemones with anoxia. Other species changed their activity
patterns, for example the circadian rhythm in the hermit crab
Paguristes eremita or the bioherm-associated crab Pisidia
longimana. Intra- and interspecific reactions were weakened or changed:
decapods ceased defensive and territorial behaviour, and predator–prey
interactions and relationships shifted. This nuanced scale of resolution is a
useful tool to interpret present benthic community status (behaviour) and
past mortalities (community composition, e.g. survival of tolerant species).
This information on the sensitivity (onset of stress response), tolerance
(mortality, survival), and characteristics (i.e. life habit, functional role)
of key species also helps predict potential future changes in benthic
structure and ecosystem functioning. This integrated approach can transport
complex ecological processes to the public and decision-makers and help
define specific monitoring, assessment and conservation plans. |
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