Egg production rates of the copepod Calanus marshallae in relation to seasonal and interannual variations in microplankton biomass and species composition in the coastal upwelling zone off Oregon, USA

摘要: Abstract In this study, we assessed trophic interactions between microplankton and copepods by studying the functional response of egg production rates (EPR; eggs female−1 day−1) copepod Calanus marshallae to variations in biomass, species composition community structure. Female C. phytoplankton water samples were collected biweekly at an inner-shelf station off Newport, Oregon USA for four years, 2011–2014, during which a total 1213 female incubated 63 experiments. On average, 80% females spawned with overall mean EPR 30.4. EPRs spring (Apr–May, average 40.2) significantly higher than summer (Jun–Oct; 26.4). intermediate winter (Jan–Feb; 32.5). Interannually, 2014 2011 2012. Total chlorophyll (Chl a) concentration diatom abundance both while no seasonal differences found dinoflagellates, ciliates or Cryptophytes. Although Chl showed interannual bulk biomass phytoplankton, structure analysis indicated among years. More diverse communities observed 2013 compared Relationships potential food variables (phytoplankton ciliates) significant season: hyperbolic was winter–spring summer, separately, ciliate winter–spring; linear model fit best summer. The estimate population recruitment rate (the number females × EPR; day−1 m−2) highest (Apr–May), annually (11,660), followed (6209), 2012 (3172) (1480). Our observations situ far published laboratory 23.5, calling into question our past studies that used mono-algae cultures as copepods. Moreover, increasing (including study) are showing apparent greater importance nutritious source demonstrating microbial loop secondary production.