Seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gda?sk Deep) ? numerical simulations

• Main Authors: Dzierzbicka-G?owacka, L., Bielecka, L., Mudrak, S.
• Other Authors: Institute of Oceanology, Polska Akademia Nauk = Polish Academy of Sciences = Académie polonaise des sciences (PAN), Institute of Oceanography, University of Gda&#x0144
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]; [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Pseudocalanus minutus; Copepods
• Online Access: https://hal.science/hal-00297587; https://hal.science/hal-00297587/document; https://hal.science/hal-00297587/file/bg-3-635-2006.pdf

International audience A population dynamics model for copepods is presented, describing the seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gda?sk Deep). The copepod model was coupled with a one-dimensional physical and biological upper layer model for nutrients (total inorganic nitrogen, phosphate), phytoplankton, microzooplankton, and an early juvenile of herring as a predator. In this model, mesozooplankton (herbivorous copepods) has been introduced as an animal having definite patterns of growth in successive stages, reproduction and mortality. The populations are represented by 6 cohorts in different developmental stages, thus assuming that recruitment of the next generation occurs after a fixed period of adult life. The copepod model links trophic processes and population dynamics, and simulates individual growth within cohorts and the changes in biomass between cohorts. The simulations of annual cycles of copepods contain one complete generation of Pseudocalanus and two generations of Acartia in the whole column water, and indicate the importance of growth in the older stages of 6 cohorts of each species, to arrive at a total population biomass. The peaks of copepods' biomass are larger at the turn of June and July for Pseudocalanus and smaller in July for Acartia , lagging that of phytoplankton by ca. two mouths, due to the growth of cohorts in successive stages and egg production by females. The numerical results show that the investigated species could not be the main factor limiting the spring phytoplankton bloom in the Gda?sk Deep, because the initial development was slow for Acartia and faster for Pseudocalanus , but the main development formed after the bloom, in both cases. The phytoplankton bloom is very important in the diet of the adults of the copepods, but it is not particularly important for the youngest part of new generation (early nauplii). However, the simulated microzooplankton biomass was enough high to conclude, in our opinion, ...