Copepod Life Strategy and Population Viability in Response to Prey Timing and Temperature: Testing a New Model across Latitude, Time, and the Size Spectrum

Abstract

A new model ("Coltrane": Copepod Life-history Traits and Adaptation to Novel Environments) describes environmental controls on copepod populations via (1) phenology and life history and (2) temperature and energy budgets in a unified framework. The model tracks a cohort of copepods spawned on a given date using a set of coupled equations for structural and reserve biomass, developmental stage, and survivorship, similar to many other individual-based models. It then analyzes a family of cases varying spawning date over the year to produce population-level results, and families of cases varying one or more traits to produce community-level results. In an idealized globalscale testbed, the model correctly predicts life strategies in large Calanus spp. ranging from multiple generations per year to multiple years per generation. In a Bering Sea testbed, the model replicates the dramatic variability in the abundance of Calanus glacialis/marshallae observed between warm and cold years of the 2000s, and indicates that prey phenology linked to sea ice is a more important driver than temperature per se. In a Disko Bay, West Greenland testbed, the model predicts the viability of a spectrum of large-copepod strategies from income breeders with a adult size ∼100 µgC reproducing once per year through capital breeders with an adult size >1000 µgC with a multiple-year life cycle. This spectrum corresponds closely to the observed life histories and physiology of local populations of Calanus finmarchicus, C. glacialis, and Calanus hyperboreus. Together, these complementary initial experiments demonstrate that many patterns in copepod community composition and productivity can be predicted from only a few key constraints on the individual energy budget: the total energy available in a given environment per year; the energy and time required to build an adult body; the metabolic and predation penalties for taking too long to reproduce; and the size and temperature dependence of the vital rates involved.

A trait-based modelling approach to planktonic foraminifera ecology

“…Traitbased models have been successfully applied to phytoplankton (e.g Follows et al, 2007;Litchman and Klausmeier, 2008;Monteiro et al, 2016) with little development and application on zooplankton (e.g. (Banas, 2011;Maps et al, 2011;2014;Banas et al, 2016). However, until now, a 115 few species models have been developed to study the ecology of modern planktonic foraminifera species: Žarić et al (2006) (from now on Žarić06), PLAFOM (Fraile et al, 2008;Fraile et al, 2009) and FORAMCLIM (Lombard et al, 2011;Roy et al, 2015).…”

Biogeographic responses of the copepod Calanus glacialis to a changing Arctic marine environment

“…Calanus glacialis , an endemic Arctic species, is widely distributed throughout the Arctic shelf/slope seas and subarctic seas (Conover, ; Falk‐Petersen et al., ). The circumpolar distributions of C. glacialis imply that this species can adapt to a wide range of environmental conditions and may utilize various life history strategies (Banas, Møller, Nielsen, & Eisner, ; Daase et al., ). Given this plasticity and adaptation to the Arctic environment, the response of this species to interannual fluctuations in environmental conditions is still largely unknown.…”

“…Various types of models have been developed and applied to investigate changing Arctic/subarctic zooplankton dynamics and the potential drivers of those changes, from fully coupled ice‐ocean‐biogeochemical models (Slagstad, Ellingsen, & Wassmann, ; Wassmann et al., ), to data‐driven statistical models (Kvile, Dalpadado, Orlova, Stenseth, & Stige, ; Questel, Blanco‐Bercial, Hopcroft, & Bucklin, ), to trait‐based (Banas et al., ) and individual‐based models (IBMs; Elliott et al., ; Coyle & Gibson, ; Feng, Ji, Campbell, Ashjian, & Zhang, ; Ji et al., ). In the Arctic Ocean, IBMs are particularly useful for overcoming the tremendous data gaps in zooplankton studies because of their capability to resolve both physical and biological processes at the individual level.…”

Dynamics of Calanus Copepodite Structure during Little Auks’ Breeding Seasons in Two Different Svalbard Locations

“…Despite differences in species composition, the significant relation between the body size of Calanus and seawater temperature observed in this study agrees with the assumptions of the temperature-size-rule (TSR) [81,82], which states that ectotherms grow slower, but mature at a larger body size in colder environments. The smaller size of Calanus in warmer temperatures observed in this study may be explained by the fact that organisms tend to be smaller in response to warming [83][84][85] and progressive reduction of Calanus body size is predicted with increasing seawater temperatures [86]. The body size of C. glacialis was found to vary considerably along its geographical range [19,20,83,87].…”

“…Studies of Calanus development are challenging because its reproductive strategies are highly variable in time and space due to corresponding changes in environmental conditions and food supply [6,20,86,95]. In this study the development of the Calanus population and in consequence also its stage index, followed similar trends in Hornsund in both years.…”