Microzooplankton grazing in the oceans: impacts, data variability, knowledge gaps and future directions

Abstract

Here we review all published data on phytoplankton growth and microzooplankton grazing using the dilution technique to better understand the role of this group of grazers in different regions of the oceans, and to identify the knowledge gaps that require future efforts. A total of 1525 data points assimilated from 110 studies were included and grouped using the biogeographic subsets defined by Longhurst et al. [(1995) An estimate of global primary production in the ocean from satellite radiometer data. J. Plankton Res., 17, 1245-1271]. Total median phytoplankton growth rates in each of the subsets varied between 0.15 (Polar Southern) and 0.83 day 21 (Trades Atlantic), with the corresponding microzooplankton grazing rates ranging between 0.07 (Polar Southern) and 0.48 day 21 (Trades Indian). The median percentage of primary production (PP) grazed by microzooplankton was relatively constant among the regions and ranged from 49

Seasonal and size-dependent variations in the phytoplankton growth and microzooplankton grazing in the southern South China Sea under the influence of the East Asian monsoon

“…All the µ (except those obtained at KJ53 during the winter cruise) and m were within the reviewed ranges based on global data collection Schmoker et al, 2013). Substantive m but negative µ were observed at KJ53 (Fig.…”

“…Phytoplankton provides almost all of the primary production in the upper ocean. Microzooplankton (< 200 µm) consumes most of the daily primary production in the sea, and regulates phytoplankton community composition, and affects the ultimate fate of the phytoplankton-derived primary production (Banse, 2007(Banse, , 2013Landry and Calbet, 2004;Schmoker et al, 2013).…”

“…Based on global data collection, Schmoker et al (2013) pointed out that seasonality of environmental variables and phytoplankton community induces seasonal variations in the phytoplankton growth and microzooplankton grazing in polar, sub-polar, and temperate regions, and tropical waters with salient seasonal reversing monsoon. However, there are few studies investigating both the phytoplankton growth and microzooplankton grazing in tropical oceans (Caron and Dennett, 1999;Chen et al, 2013;Landry et al, 1995Landry et al, , 1998Landry et al, , 2011, and the seasonality of phytoplankton growth and microzooplankton grazing in tropical waters influenced by salient seasonal reversing monsoon is still less known.…”

Temporal variation of phytoplankton growth and grazing loss in the west coast of Peninsular Malaysia

“…From a cross-compilation of 66 studies, Calbet and Landry (2004) revealed that grazing loss accounts for 60 -75% of daily phytoplankton production, and is higher in estuarine and coastal waters than in oceanic waters. Although it is generally accepted that grazing loss is higher in productive waters (Schmoker et al 2013), the impact of grazing loss is still not clear as grazing loss rates are extremely variable, are sitespecific and can be affected by multiple environmental drivers e.g. temperature (Irwin andOliver 2009, Boyce et al 2010).…”

“…Other than filling an obvious data gap (Schmoker et al 2013), it is vital to investigate the phytoplankton production and grazing loss in tropical waters in view of the current global climate change (IPCC 2007). Ocean warming is expected to have the strongest 10 effect in tropical waters where most organisms are already functioning at or near optimum temperatures (Pomeroy and Wiebe 2001).…”