Risposte biologiche delle Corallinales ai cambiamenti climatici globali: proposta di un percorso didattico per imparare a pensare la complessità dell’ecosistema

La riduzione del pH dell’acqua marina (ocean acidification) causata del progressivo aumento della CO2 atmosferica sembra essere un fenomeno poco noto. Con l’obiettivo di creare un canale diretto fra la ricerca ed il sistema scolastico, l’Università di Trieste ha instaurato un rapporto di collaborazione con una scuola media, offrendo un corso sperimentale per gli studenti sul tema dei cambiamenti climatici globali e acidificazione del mare. Durante il corso sono state evidenziate le reazioni all’acidificazione di alghe rosse calcaree durante la fase riproduttiva. Gli studenti hanno imparato a usare strumenti, a raccogliere dati quantitativi e qualitativi, a rappresentarli, elaborarli e trarre conclusioni dai risultati. Il corso è stato un’opportunità per trasferire ai giovani conoscenze sui cambiamenti climatici globali e per utilizzare un metodo didattico innovativo con lo scopo di implementare abilità e competenze scientifiche a livello scolastico.Questo numero della rivista è stato pubblicato con il contributo della Fondazione CRTriest

Determining a threshold in effect of ocean acidification on crustose coralline algae (including a case study to teach at school)

2010/2011The recent and steady CO2 increase, mainly due to human activities, causes a shift in the chemical equilibrium of the carbonates dissolved in sea-water, which results in a lowering of pH level. This phenomenon, known as ocean acidification, interacts with many physiological processes, including, calcification due to biological factors. Plenty of consequences can affect both the ecosystem and the human society; the latter benefits from goods and services produced by the ecosystem itself, such as fishing, shoreline protection, landscape, tourist and recreational activities. It seems there isn’t much awareness of all of this. The study of the effect of acidification on coralline algae (Corallinales) is of primary importance for the comprehension of the consequences at ecosystem level, since the Corallinales represent one of the key groups in the formation of submerged habitats, but also because they’ve proven to be some of the most responsive to acidification. The question that was tried to answer is whether the calcareous algae can be resilient towards acidification and, if that is so, which is the threshold value beyond which that ability expires. In this analysis, particular attention has been paid to reproductive phases, that represent a de facto sensitive point in the life cycle.Il recente e costante aumento della CO2 dovuto principalmente alle attività antropiche provoca un’alterazione dell’equilibrio chimico dei carbonati disciolti nell’acqua marina, che si traduce in un abbassamento del pH. Questo fenomeno, noto come ocean acidification, interagisce con numerosi processi fisiologici fra cui, in primis, la calcificazione di origine biologica. Numerose potrebbero essere le conseguenze sugli ecosistemi, e quindi anche sulla società umana, che usufruisce di beni e servizi prodotti dagli ecosistemi stessi, come la pesca, la protezione della linea di costa, il paesaggio e le attività turistico - ricreative. Di tutto questo non sembra esserci in realtà grande consapevolezza. Lo studio degli effetti dell’acidificazione sulle alghe rosse calcaree (Corallinales) è di primaria importanza nella comprensione delle conseguenze a livello di ecosistema, in quanto le Corallinales rappresentano uno dei gruppi chiave nella formazione di habitat sommersi, ma anche perché esse si sono rivelate fra gli organismi più sensibili all’acidificazione. Il quesito di fondo a cui si è cercato quindi di dare una risposta è quale sia la resilienza da parte delle alghe calcaree nei confronti dell’acidificazione e quale possa essere il valore soglia al di là del quale tale capacità venga meno. In questa analisi, particolare attenzione è stata rivolta alle fasi riproduttive, che potrebbero rappresentare la fase più sensibile nel ciclo vitale.XXIV Ciclo196

The future of the northeast Atlantic benthic flora in a high CO₂ world

Seaweed and seagrass communities in the northeast Atlantic have been profoundly impacted by humans, and the rate of change is accelerating rapidly due to runaway CO2 emissions and mounting pressures on coastlines associated with human population growth and increased consumption of finite resources. Here, we predict how rapid warming and acidification are likely to affect benthic flora and coastal ecosystems of the northeast Atlantic in this century, based on global evidence from the literature as interpreted by the collective knowledge of the authorship. We predict that warming will kill off kelp forests in the south and that ocean acidification will remove maerl habitat in the north. Seagrasses will proliferate, and associated epiphytes switch from calcified algae to diatoms and filamentous species. Invasive species will thrive in niches liberated by loss of native species and spread via exponential development of artificial marine structures. Combined impacts of seawater warming, ocean acidification, and increased storminess may replace structurally diverse seaweed canopies, with associated calcified and noncalcified flora, with simple habitats dominated by noncalcified, turf-forming seaweeds.</p

Risposte biologiche delle Corallinaceae ai cambiamenti climatici globali e come utilizzarle nell'insegnamento nella scuola secondaria di primo grado (scuola media).Biological response of the Corallinaceae to global climate change and how to use it in teaching at middle school.

The rising of atmospheric CO2 partial pressure moves marine water pH onto a lower grade. Many marine organisms, that use CaCO3 to build their skeletons, seem to be damaged by Ocean Acidification; especially shallow water ecosystems are at risk. A study on juvenile thalli of calcareous red algae was carried out in a microcosm experiment underdifferent acidic conditions. The encouraging preliminary result suggested taking the experience to educational system: a partnership with a middle school was established to fill the gap between research and school. An experimental course on global climate change and ocean acidification was offered to 14 years-old pupils. The course, experimentally based on calcareous red algae, represents not only a way to spread knowledge on global climatic change among the young, but also a tool to measure how much new methods of teaching can improve scientific knowledge and skills at school level

Risposte biologiche delle Corallinales ai cambiamenti climaticiglobali: proposta di un percorso didattico per imparare a pensarela complessit\ue0 dell\u2019ecosistema

La riduzione del pH dell\u2019acqua marina (ocean acidification) causata del progressivo aumento della CO2 atmosferica sembra essere un fenomeno poco noto. Con l\u2019obiettivo di creare un canale diretto fra la ricerca ed il sistema scolastico, l\u2019Universit\ue0 di Trieste ha instaurato un rapporto di collaborazione con una scuola media, offrendo un corso sperimentale per gli studenti sul tema dei cambiamenti climatici globali e acidificazione del mare. Durante il corso sono state evidenziate le reazioni all\u2019acidificazione di alghe rosse calcaree durante la fase riproduttiva. Gli studenti hanno imparato a usare strumenti, a raccogliere dati quantitativi e qualitativi, a rappresentarli, elaborarli e trarre conclusioni dai risultati. Il corso \ue8 stato un\u2019opportunit\ue0 per trasferire ai giovani conoscenze sui cambiamenti climatici globali e per utilizzare un metodo didattico innovativo con lo scopo di implementare abilit\ue0 e competenze scientifiche a livello scolastico. PAROL

OCEAN ACIDIFICATION: A SCHOOL EXPERIMENT

participantMarine water is becoming more acidic because of the rising of atmospheric CO2 partial pressure and thats seems to be almost unknown to the public. A partnership with a middle school was established by the University of Trieste to fill the gap between research and educational system. An experimental course on global climate change and ocean acidification was offered to 14 years-old pupils. The course was experimentally based on thallus of calcareous red algae grown under different acidic conditions. Pupils also learned to use instruments, collect qualitative and numerical data and represent the data, elaborate them and take conclusion from the outcoming. In order to evaluate the project 21 students have been chosen randomly. Another 21 students, not taking part of the lessons, represent the control group. All the students have been tested at the beginning and at the conclusion of the school year (May 2010). OCSE PISA-like tests have been used to estimate previous and final skills and knowledge, and homogeneity between the two tested groups. The course represents not only a way to spread knowledge on global climatic change among the youngs, but also a tool to measure how much new methods of teaching can improve scientifical knowlegde and skills at school level

OCEAN ACIDIFICATION: A SCHOOL EXPERIMENT

participantMarine water is becoming more acidic because of the rising of atmospheric CO2 partial pressure and thats seems to be almost unknown to the public. A partnership with a middle school was established by the University of Trieste to fill the gap between research and educational system. An experimental course on global climate change and ocean acidification was offered to 14 years-old pupils. The course was experimentally based on thallus of calcareous red algae grown under different acidic conditions. Pupils also learned to use instruments, collect qualitative and numerical data and represent the data, elaborate them and take conclusion from the outcoming. In order to evaluate the project 21 students have been chosen randomly. Another 21 students, not taking part of the lessons, represent the control group. All the students have been tested at the beginning and at the conclusion of the school year (May 2010). OCSE PISA-like tests have been used to estimate previous and final skills and knowledge, and homogeneity between the two tested groups. The course represents not only a way to spread knowledge on global climatic change among the youngs, but also a tool to measure how much new methods of teaching can improve scientifical knowlegde and skills at school level

Contrasting Effects of Ocean Acidification on Coral Reef “Animal Forests” Versus Seaweed “Kelp Forests”

Ocean acidification is the sustained absorption of anthropogenically derived CO2 and is a major threat to marine ecosystems. Ocean acidification results in the decline of seawater pH (increase in protons) and carbonate ions and increased CO2. Added CO2 could benefit terrestrial forests, but changes in the concentration of any one of aspect of the carbonate system could affect various marine organisms both positively and negatively. One ecosystem under particular threat from ocean acidification is tropical coral reefs, formed predominately by scleractinian coral species that are predicted to be negatively impacted by ocean acidification. In contrast, temperate shallow rocky reefs are dominated by seaweed that forms extensive kelp/seaweed forests; these noncalcareous seaweeds are not predicted to be as negatively impacted by ocean acidification. Tropical coral reef “animal forests” and temperate “kelp forests” both provide three-dimensional habitat for tens of thousands of species, but are characterized by vastly different environmental regimes. The present chapter outlines differences in key environmental parameters (such as nutrients, water motion, and temperature) in these two habitats that could dictate the relative magnitudes of the effects of ocean acidification within them. The vulnerability of key habitat-forming organisms within these habitats and the potential mechanisms behind specific responses to ocean acidification are also discussed