Primary production and carbon uptake dynamics in the vicinity of South Georgia – balancing carbon fixation and removal
Primary production was measured at a series of stations in austral summer 1996 in the vicinity of South Georgia. Five stations were occupied along a 700 km transect southeastwards towards the western tip of South Georgia. Three stations were located north of the Antarctic Polar Front (PF) with mean primary production of 0.41 g C m(-2) d(-1) compared to 0.54 g C m(-2) d(-1) for the stations south of the front. Three stations were in the shelf break and off-shelf region to the east of South Georgia where the lowest rates of primary production were recorded (mean 0.34 g C m(-2) d(-1)). At a further 4 stations northwest of the island, primary production was significantly greater: 0.8 to 2.5 g C m(-2) d(-1) (mean 1.5 g C m(-2) d(-1)). Photoinhibition was a marked feature of the production profiles, resulting in the underestimation of column production by 4 to 16%. An assessment is made of the primary production required to maintain a representative assemblage of metazooplankton around South Georgia composed of 30 g fresh mass (FM) m(-2) krill and 20 g FM m(-2) copepods. The total C requirement of both groups at maximum growth rate is estimated as 0.93 g C m(-2) d(-1), with 0.54 g C m(-2) d(-1) required to maintain basal metabolism (i.e. for zero growth). Local primary production rates are well in excess of the C demands for basal metabolism by the metazooplankton, and likewise the highest regional values exceed those for maximum metazooplankton growth. It is also estimated that the krill biomass required to sustain higher predators during their breeding season could be supported by local production at plausible maximum krill growth rate. In particular, high primary production found in this study to the northwest of South Georgia appears to be adequate to sustain maximum growth rate by krill when their biomass is 30 g FM m(-2), when krill production will exceed predator removal. It is already well known that advection from,higher latitudes is important in supplying energy to the South Georgia system. This study adds to the evidence that locally enhanced primary production is also important in supporting the local food web.
This website uses cookies to improve your experience. We'll assume you're okay with this, but you can opt-out if you wish.AcceptRead more
Privacy & Cookies Policy
Privacy Overview
This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may affect your browsing experience.
Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.