Nettsider med emneord «Plankton»
Phytoplankton biomass is controlled by a combination of “bottom-up” factors such as temperature, light and nutrients and “top-down” factors, in particular zooplankton predation. In a recent study we analysed large-scale data on ocean chlorophyll, copepod abundance and temperature in order to assess the general importance of bottom-up and top-down factors in controlling phytoplankton biomass.
Statistical analyses of long-term monitoring data reveal an inverse relationship between the biomasses of zooplankton and plankton-eating fish, but only in the northern and central parts of the Barents Sea. In the southwestern Barents Sea, so such relationship is found.
In a study recently published in Ecology we find apparent competition between major zooplankton groups in a large marine ecosystem. Apparent competition is an indirect, negative interaction between two species or species groups mediated by a third species other than their prey.
We assessed the effect of the predator−prey relationship on predator survival by developing a novel metric of predator−prey overlap using spatio-temporal statistical models. We found that the amount of overlap between cod larvae (length: 11−15 mm) and their prey explained 29 % of cod recruitment variability.