COMBINED EFFECTS OF DISSOLVED ORGANIC CARBON AND ZOOPLANKTON GRAZING ON PHYTOPLANKTON COMMUNITY

Download

Tez_pdf_son-3.pdf

Date

2022-6-22

Author

Metin, Melisa

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

277
views

166
downloads

While global climate change has major impacts on freshwater ecosystems, a mechanistic understanding of these effects on food web dynamics is poorly understood. A key effect of climate change is increased allochthonous dissolved organic carbon (DOC) input to aquatic environments, which serves as an energy source for heterotrophic plankton and alters food web dynamics, and leads brownification. We aimed to link patterns and processes in a plankton ecosystem by comparing the bottom-up effects of DOC (i.e., recalcitrant and leaf leachate sources) to the top-down effects of zooplankton with contrasting grazing selectivity (Daphnia vs. calanoid copepods) on phytoplankton biomass and composition in laboratory and in-situ mesocosm grazing assays. We expected that DOC and zooplankton would reduce phytoplankton biomass; stronger herbivory by Daphnia than copepods; and stronger grazing on larger-sized phytoplankton. In the nutrient replete laboratory experiment, DOC reduced total phytoplankton biomass (especially smaller sized species). While grazers reduced total phytoplankton, they increased smaller phytoplankton and decreased larger phytoplankton biomass. Moreover, copepods were stronger herbivores than Daphnia. In nutrient limited mesocosm experiments DOC increased phytoplankton biomass, though species-specific responses varied across treatments and time. Hence, labile DOC may reduce phytoplankton biomass in nutrient replete conditions, and increase phytoplankton during nutrient limitation. Mesozooplankton grazing is expected to reduce mostly larger sized phytoplankton (~20µm), with calanoid copepods having a stronger mass-specific effect than Daphnia. Results highlight the DOC quality’s roles, nutrient and light limitation, microbial grazing, and meso-zooplankton traits as key regulators of phytoplankton community dynamics and plankton trophic interactions in a changing world.

Subject Keywords

Phytoplankton, Food Web, Selectivity, DOC, Leaf-leachate

URI

https://hdl.handle.net/11511/98140

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

EFFECTS OF DISSOLVED ORGANIC CARBON (DOC) AND ZOOPLANKTON GRAZING PRESSURE ON BACTERIA AND CILIATES Yetim, Sinem; Beklioğlu, Meryem; Ger, Kemal Ali; Department of Biology (2021-11-24) Global climate change results in extreme precipitation events that increase allochthonous organic matter (e.g., dissolved organic carbon, DOC) input into freshwater ecosystems via flooding. While DOC is a source of carbon and energy for heterotrophic organisms in freshwater ecosystems, its bottom-up effects on trophic interactions, and especially on the microbial food web, are poorly understood. Similarly, the top-down effect of contrasting zooplankton traits (i.e., generalist vs. selective) on DOC enriched...
Interactive Effects of Lake Morphometry and Sticklebacks on the Trophic Position of Arctic charr (Salvelinus alpinus) across Lakes in Western Greenland Arranz, Ignasi; Davidson, Thomas Alexander; Benejam, Lluís; Brucet, Sandra; Sánchez-Hernández, Javier; Landkildehus, Frank; Lauridsen, Torben; Mazzeo, Nestor; Vidal, Nicolas; Özkan, Korhan; Gallego, Irene; Wischnewski, Juliane; Menezes, Rosemberg; Shurkhuu, Tserenpil; Jeppesen, Erik (2022-01-01) The structure and functioning of Arctic ecosystems have been drastically modified by global warming, with fish species potentially performing habitat shifts such as the northern expansion of generalist and warm-adapted species. The freshwater fish species Arctic charr (Salvelinus alpinus, hereafter charr) plays a key role in Arctic lake food webs, but sticklebacks (Gasterosteus aculeatus) may impact the trophic position (TP) of charr by affecting their habitat choice and food resources. In the present study...
Comparison of Productivity Plankton Types and Carbon Export Mechanisms in two Different Regimes of Subtropical North Atlantic a Modeling Study Salihoğlu, Barış (2016-02-15) Improved structure and mechanisms of carbon export and sequestration within marine ecosystem models is vital to better understand and predict changes in the global carbon cycle. We have implemented a 1D lower trophic ecosystem model at long-term time-series stations (BATS and ESTOC) in the North Atlantic for the years 1996-2000. We have investigated the dynamics of the productivity and carbon export, and mechanisms regulating them. Our simulations agree with the previous observations that show similar produ...
Modeling the current and future ranges of Turkish pine (Pinus Brutia) and oriental beech (Fagus Orientalis) in Turkey in the face of climate change Yalçın, Semra; Bilgin, Cemal Can; Düzgün, H. Şebnem; Department of Geodetic and Geographical Information Technologies (2012) Climate change is widely recognized to have potential impacts on global biotic and abiotic systems. One of the major impacts is expected on species distributions. Species distribution models (SDMs) are used for estimating the relationship between species occurrences at sites and environmental and/or spatial characteristics of those sites. SDMs can be used to understand possible responses of species to climate change. Despite some sources of uncertainty, projections onto future climate are useful and cost-ef...
Integrated nutrient removal and biogas production by Chlorella vulgaris cultures Calicioglu, Ozgul; Demirer, Göksel Niyazi (AIP Publishing, 2015-05-01) Changes in global nutrient cycles as a result of industrialization affect both ecosystems and human well-being. A clear example of human manipulation on ecosystems is eutrophication; a phenomenon caused in receiving water bodies by discharge of urban sewage rich in nutrients such as nitrogen (N) and phosphorus (P). Microalgal nutrient removal is a viable alternative for biological wastewater treatment, considering high nutrient uptake capabilities of microalgae. These systems are also advantageous in terms ...

Citation Formats

M. Metin, “COMBINED EFFECTS OF DISSOLVED ORGANIC CARBON AND ZOOPLANKTON GRAZING ON PHYTOPLANKTON COMMUNITY,” M.S. - Master of Science, Middle East Technical University, 2022.