Climate change is considered to be one of the most severe threats to earth and aquatic ecosystems and the concern about the effects that global warming can have on biological communities is growing. Even if the number of studies concerning climate change is worldwide increasing the effects of climate change are challenging to monitor and understand because of the multitude of responses within an ecosystem. In the last years, analyses of long-term data sets provide increasing evidence on the sensitivity of water bodies to climatic fluctuation. Small size and fast reproducing zooplankton organisms are sensitive to environmental change. Moreover, they represent key components of aquatic food webs, connecting primary producers to big secondary consumers as fishes. The purpose of the present PhD research is to expand the knowledge on the zooplankton communities of the large and deep lakes south of the Alps, detecting trends and significant change or shift in the pelagic food webs structure due to global or local impacts. The analysis of long-term series of limnological observations and a paleolimnological study on lake sediment have been combined in order to disentangle the effects of climate change from that due to more local and anthropic stressor as eutrophication. The obtained results suggested that in deep subalpine lakes the effect of climate change on pelagic food webs components is complex, including several direct and indirect effects, and it is mediated by nutrient availability. In particular, in deep lakes winter climatic variability trigger a cascading effect that involves the entire lake ecosystems, modifying lake chemical, physical and biological characteristic. The effects of warmer winter temperature can reverberate on zooplankton seasonal patterns until summer, affecting the food webs functioning. The paleolimnological investigation, through the combined study of biotic and abiotic factor, allowed clarifying the synergic effects of the most important drivers of change in lake ecosystems, suggesting that climatic factors should be considered with nutrient availability as a determinant element in controlling the temporal development of plankton communities and pelagic food web structure.

Il cambiamento climatico è considerato una delle minacce più gravi per la terra e gli ecosistemi acquatici e cresce la preoccupazione per gli effetti che il riscaldamento globale può avere sulle comunità biologiche. Negli ultimi anni, diversi studi hanno evidenziato la sensibilità dei corpi idrici alle fluttuazioni climatiche. Gli organismi zooplanctonici, caratterizzati da piccole dimensioni e rapido ciclo riproduttivo, sono sensibili ai cambiamenti ambientali. Inoltre, rappresentano dei componenti chiave delle catene trofiche acquatiche, collegando i produttori primari ai grandi consumatori secondari come pesci. Lo scopo della presente ricerca di dottorato è di ampliare le conoscenze sulle comunità zooplanctoniche dei grandi laghi subalpini, rilevando tendenze e cambiamenti nella struttura delle reti trofiche pelagiche e le loro potenziali cause. L’analisi di dati limnologici a lungo termine combinata a uno studio paleolimnologico del lago d’Iseo ha permesso di distinguere gli effetti dovuti al cambiamento climatico a quelli dovuti a impatti più locali, come l’eutrofizzazione. I risultati evidenziano che le rete trofiche dei laghi profondi subalpini sono fortemente influenzate dal clima. In particolare, la variabilità climatica invernale provoca un effetto a cascata che coinvolge l'intero ecosistema lacustre, modificando le caratteristiche chimiche, fisiche e biologiche del lago. Gli effetti del riscaldamento delle temperature invernali possono ripercuotersi sulle dinamiche di popolazione dello zooplancton fino all'estate, influenzando il funzionamento dell’intera catena trofica. L'indagine paleolimnologica, attraverso lo studio combinato di fattori biotici e abiotici, ha permesso di considerare gli effetti dei più importanti fattori di cambiamento negli ecosistemi lacustri, suggerendo che i fattori climatici dovrebbero essere considerati di fondamentale importanza nel determinare le dinamiche di sviluppo delle comunità planctoniche e la struttura e il funzionamento delle reti trofiche pelagiche.

(2020). ZOOPLANKTONIC POPULATION DYNAMICS AND PELAGIC FOOD WEBS IN THE DEEPEST SUBALPINE LAKES RELATED TO ANTHROPOGENIC PRESSURE AND CLIMATE CHANGE. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2020).

ZOOPLANKTONIC POPULATION DYNAMICS AND PELAGIC FOOD WEBS IN THE DEEPEST SUBALPINE LAKES RELATED TO ANTHROPOGENIC PRESSURE AND CLIMATE CHANGE

PATELLI, MARTINA
2020

Abstract

Climate change is considered to be one of the most severe threats to earth and aquatic ecosystems and the concern about the effects that global warming can have on biological communities is growing. Even if the number of studies concerning climate change is worldwide increasing the effects of climate change are challenging to monitor and understand because of the multitude of responses within an ecosystem. In the last years, analyses of long-term data sets provide increasing evidence on the sensitivity of water bodies to climatic fluctuation. Small size and fast reproducing zooplankton organisms are sensitive to environmental change. Moreover, they represent key components of aquatic food webs, connecting primary producers to big secondary consumers as fishes. The purpose of the present PhD research is to expand the knowledge on the zooplankton communities of the large and deep lakes south of the Alps, detecting trends and significant change or shift in the pelagic food webs structure due to global or local impacts. The analysis of long-term series of limnological observations and a paleolimnological study on lake sediment have been combined in order to disentangle the effects of climate change from that due to more local and anthropic stressor as eutrophication. The obtained results suggested that in deep subalpine lakes the effect of climate change on pelagic food webs components is complex, including several direct and indirect effects, and it is mediated by nutrient availability. In particular, in deep lakes winter climatic variability trigger a cascading effect that involves the entire lake ecosystems, modifying lake chemical, physical and biological characteristic. The effects of warmer winter temperature can reverberate on zooplankton seasonal patterns until summer, affecting the food webs functioning. The paleolimnological investigation, through the combined study of biotic and abiotic factor, allowed clarifying the synergic effects of the most important drivers of change in lake ecosystems, suggesting that climatic factors should be considered with nutrient availability as a determinant element in controlling the temporal development of plankton communities and pelagic food web structure.
LEONI, BARBARA
SALMASO, NICO
climate change; laghi profondi; eutrofizzazione; catene trofiche; zooplancton
climate change; eutrophication; deep lakes; food webs; zooplancton
BIO/07 - ECOLOGIA
Italian
11-feb-2020
SCIENZE CHIMICHE, GEOLOGICHE E AMBIENTALI
32
2018/2019
open
(2020). ZOOPLANKTONIC POPULATION DYNAMICS AND PELAGIC FOOD WEBS IN THE DEEPEST SUBALPINE LAKES RELATED TO ANTHROPOGENIC PRESSURE AND CLIMATE CHANGE. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2020).
File in questo prodotto:
File Dimensione Formato  
phd_unimib_726543.pdf

accesso aperto

Descrizione: tesi di dottorato
Dimensione 2.08 MB
Formato Adobe PDF
2.08 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/262346
Citazioni
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
Social impact