Productivity and carbon transfer in pelagic food webs in response to carbon, nutrients and light
Some of the major problems we face today are human induced changes to the nitrogen (N), phosphorus (P) and carbon (C) cycles. Predicted increases in rainfall and temperature due to climate change, may also increase dissolved organic matter (DOM) inflows to freshwater ecosystems in the boreal zone. N...
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Institutionen för ekologi, miljö och geovetenskap
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ftumeauniv:oai:DiVA.org:umu-43467 2023-10-09T21:56:31+02:00 Productivity and carbon transfer in pelagic food webs in response to carbon, nutrients and light Faithfull, Carolyn 2011 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-43467 eng eng Institutionen för ekologi, miljö och geovetenskap Umeå : Institutionen för ekologi, miljö och geovetenskap, Umeå universitet http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-43467 urn:isbn:978-91-7459-191-0 info:eu-repo/semantics/openAccess bacterial production phytoplankton production mesocosms food webs carbon nutrients light Ecology Ekologi Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2011 ftumeauniv 2023-09-22T13:49:30Z Some of the major problems we face today are human induced changes to the nitrogen (N), phosphorus (P) and carbon (C) cycles. Predicted increases in rainfall and temperature due to climate change, may also increase dissolved organic matter (DOM) inflows to freshwater ecosystems in the boreal zone. N, P, C and light, are essential resources that most often limit phytoplankton (PPr) and bacterial production (BP) in the pelagic zone of lakes. PPr and BP not only constitute the total basal C resource for the pelagic aquatic food web, but also influence ecosystem function and biogeochemical cycles. In this thesis I studied how N, P, C and light affect the relative and absolute rates of PPr and BP, along a wide latitudinal and trophic gradient using published data, and in two in situ mesocosm experiments in a clear water oligotrophic lake. In the experiments I manipulated bottom-up drivers of production and top-down predation to examine how these factors interact to affect pelagic food web structure and function. The most important predictors of PPr globally (Paper I) were latitude, TN, and lake shape. Latitude alone explained the most variation in areal (50%) and volumetric (40%) PPr. In terms of nutrients PPr was primarily N-limited and BP was P-limited. Therefore bacteria and phytoplankton were not directly competing for nutrients. BP:PPr was mostly driven by PPr, therefore light, N, temperature and other factors affecting PPr controlled this ratio. PPr was positively correlated with temperature, but not BP, consequently, higher temperatures may reduce BP:PPr and hence the amount of energy mobilised through the microbial food web on a global scale. In papers II and III interaction effects were found between C-additions and top-down predation by young-of-the-year (YOY) perch. Selective predation by fish on copepods influenced the fate of labile C-addition, as rotifer biomass increased with C-addition, but only when fish were absent. Interaction effects between these top-down and bottom-up drivers were evident in ... Doctoral or Postdoctoral Thesis Copepods Rotifer Umeå University: Publications (DiVA) |
institution |
Open Polar |
collection |
Umeå University: Publications (DiVA) |
op_collection_id |
ftumeauniv |
language |
English |
topic |
bacterial production phytoplankton production mesocosms food webs carbon nutrients light Ecology Ekologi |
spellingShingle |
bacterial production phytoplankton production mesocosms food webs carbon nutrients light Ecology Ekologi Faithfull, Carolyn Productivity and carbon transfer in pelagic food webs in response to carbon, nutrients and light |
topic_facet |
bacterial production phytoplankton production mesocosms food webs carbon nutrients light Ecology Ekologi |
description |
Some of the major problems we face today are human induced changes to the nitrogen (N), phosphorus (P) and carbon (C) cycles. Predicted increases in rainfall and temperature due to climate change, may also increase dissolved organic matter (DOM) inflows to freshwater ecosystems in the boreal zone. N, P, C and light, are essential resources that most often limit phytoplankton (PPr) and bacterial production (BP) in the pelagic zone of lakes. PPr and BP not only constitute the total basal C resource for the pelagic aquatic food web, but also influence ecosystem function and biogeochemical cycles. In this thesis I studied how N, P, C and light affect the relative and absolute rates of PPr and BP, along a wide latitudinal and trophic gradient using published data, and in two in situ mesocosm experiments in a clear water oligotrophic lake. In the experiments I manipulated bottom-up drivers of production and top-down predation to examine how these factors interact to affect pelagic food web structure and function. The most important predictors of PPr globally (Paper I) were latitude, TN, and lake shape. Latitude alone explained the most variation in areal (50%) and volumetric (40%) PPr. In terms of nutrients PPr was primarily N-limited and BP was P-limited. Therefore bacteria and phytoplankton were not directly competing for nutrients. BP:PPr was mostly driven by PPr, therefore light, N, temperature and other factors affecting PPr controlled this ratio. PPr was positively correlated with temperature, but not BP, consequently, higher temperatures may reduce BP:PPr and hence the amount of energy mobilised through the microbial food web on a global scale. In papers II and III interaction effects were found between C-additions and top-down predation by young-of-the-year (YOY) perch. Selective predation by fish on copepods influenced the fate of labile C-addition, as rotifer biomass increased with C-addition, but only when fish were absent. Interaction effects between these top-down and bottom-up drivers were evident in ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Faithfull, Carolyn |
author_facet |
Faithfull, Carolyn |
author_sort |
Faithfull, Carolyn |
title |
Productivity and carbon transfer in pelagic food webs in response to carbon, nutrients and light |
title_short |
Productivity and carbon transfer in pelagic food webs in response to carbon, nutrients and light |
title_full |
Productivity and carbon transfer in pelagic food webs in response to carbon, nutrients and light |
title_fullStr |
Productivity and carbon transfer in pelagic food webs in response to carbon, nutrients and light |
title_full_unstemmed |
Productivity and carbon transfer in pelagic food webs in response to carbon, nutrients and light |
title_sort |
productivity and carbon transfer in pelagic food webs in response to carbon, nutrients and light |
publisher |
Institutionen för ekologi, miljö och geovetenskap |
publishDate |
2011 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-43467 |
genre |
Copepods Rotifer |
genre_facet |
Copepods Rotifer |
op_relation |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-43467 urn:isbn:978-91-7459-191-0 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1779321335865933824 |