Control of dormancy by lipid metabolism in Calanus finmarchicus: a population model test

• Published in: Marine Ecology Progress Series
• Main Authors: Maps, Frederic, Plourde, Stephane, ZAKARDJIAN, Bruno
• Other Authors: Laboratoire de sondages électromagnétiques de l'environnement terrestre (LSEET), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: MARINE COPEPOD; DEVELOPMENT RATES; LABRADOR SEA; GEORGES BANK; VERTICAL MIGRATION; Calanus finmarchicus; Dormancy; Lipid; Numerical modeling; Gulf of St. Lawrence; ST-LAWRENCE ESTUARY; LIFE-HISTORY MODEL; NORTH-ATLANTIC; NORWEGIAN SEA; SCOTIAN SHELF; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Canada; Norwegian Sea; Labrador Sea; North Atlantic; Subarctic
• Online Access: https://hal.archives-ouvertes.fr/hal-00721954; https://hal.archives-ouvertes.fr/hal-00721954/document; https://hal.archives-ouvertes.fr/hal-00721954/file/m403p165.pdf; https://doi.org/10.3354/meps08525

International audience The life cycle of Calanus finmarchicus includes a prolonged dormancy phase that allows it to avoid the unfavourable environmental conditions typical of the upper ocean from late summer to early spring in the subarctic North Atlantic. Recent demographic, physiological and genetic evidence supports the hypothesis of a crucial role for lipid accumulation and metabolism in the control of dormancy. We present a stage-resolving biomass model of C. finmarchicus, implementing a mechanistic approach of the control of dormancy based on this lipid hypothesis. The dormancy process obeys 2 rules: (1) active copepodite stage Vs (C5s) enter dormancy when the ratio of lipid to total body carbon exceeds some threshold, and (2) diapausing C5s exit dormancy when their lipid storage approaches a lower threshold. We implemented the model into a 1-dimensional water column framework and compared our results to 2 consecutive years of observations of stage-specific copepodite abundances and lipid content of C5 from the Northwest Gulf of St. Lawrence, Canada. The model produced realistic phenology and temporal patterns in lipid content of C. finmarchicus in response to the observed environmental forcing. Interannual variations in the timing of entry and contributions of different generations to the overwintering stock were shown. Our results are consistent with the hypothesis of a lipid-mediated control of entrance and exit from dormancy in C. finmarchicus.