IMPACT OF CLIMATE CHANGE ON PHYTOPLANKTON IN THE RIA FORMOSA COASTAL LAGOON: EFFECTS OF ULTRAVIOLET RADIATION, CO2 AND TEMPERATURE1 495,00

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Psychometric properties of the Portuguese Environmental Attitudes Inventory

Publication . Domingues, Rita B.; Fernandes, Maria Jacinta; Cabral, Maria

This paper aimed to assess the structural validity of the Portuguese version (EAI-PT) of the Environmental Attitudes Inventory using exploratory (EFA) and confirmatory factor analysis (CFA). EFA showed that all 12 EAI-PT scales have adequate reliabilities. Ten scales loaded heavily on one higher-order factor, whilst scales 5 (confidence in science and technology) and 12 (support for population growth policies) loaded on a different factor; moreover, these scales did not correlate with any other scale, indicating that they are not related to environmental attitudes in the Portuguese population. The removal of these two scales and five items from other scales is suggested, resulting in an EAI-PT version with 95 items and 10 scales. CFA confirmed that a vertical structure of EA with either two second-order factors that reflect the dilemma between Preservation and Utilization or one secondorder factor that expresses a bipolar view of environmental attitudes are equally adequate.

2019Journal article

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Seasonal and spatial variability of Phytoplankton primary production in a shallow temperate Coastal Lagoon (Ria Formosa, Portugal)

Publication . B. Domingues, Rita

Coastal lagoons are among the most productive ecosystems in the world, and they provide a wide range of ecosystem services and resources. In the Ria Formosa (southern Portugal), phytoplankton production has rarely been addressed. The main goal of this study is thus to evaluate the variability of phytoplankton production and photosynthetic characteristics over the seasonal cycle and in different locations (landward, urban, intermediate, and seaward boundaries) of the Ria Formosa coastal lagoon, subjected to distinct natural and anthropogenic stressors. Primary production was evaluated using the ¹⁴C incorporation technique, and photosynthetic parameters were estimated by fitting photosynthesis-irradiance curves. Primary production showed significant seasonal variations, with higher values in the summer associated with lower euphotic depths, higher water temperatures, and higher nutrient concentrations. No spatial differences were found for primary production or photosynthetic parameters. Primary production values were lower than previous estimates, which reflects an improvement in water quality in the Ria Formosa, but values are higher than primary production estimates for other temperate coastal ecosystems, which reflects the highly productive nature of this coastal lagoon.

2022-12-14Journal article

Open access

Co-limitation of phytoplankton by N and P in a shallow coastal lagoon (Ria Formosa): implications for eutrophication evaluation

Publication . Domingues, Rita B.; Nogueira, Patricia; Barbosa, Ana B.

The Ria Formosa coastal lagoon is a highly productive shallow ecosystem in southern Portugal, subjected to nutrient inputs from anthropogenic and natural sources. Nutrients are major abiotic drivers of phytoplankton in this system, but their effects on phytoplankton assemblages and the occurrence of nutrient limitation are still poorly understood. The main goal of this study was, thus, to evaluate the occurrence, type, and effects of nutrient limitation on phytoplankton community and specific functional groups in the Ria Formosa coastal lagoon. We conducted nutrient enrichment experiments with factorial additions of nitrogen (N) and phosphorus (P) using natural phytoplankton assemblages from distinct locations in the Ria Formosa, throughout a yearly cycle. Phytoplankton composition and abundance were evaluated using inverted and epifluorescence microscopies, and spectrophotometric methods were used for biomass. Limitation was defined as higher phytoplankton growth following enrichment with a particular nutrient in relation to the non-enriched control. The most common type of phytoplankton limitation was simultaneous co-limitation by N and P; diatoms, as r-strategists, were the most frequently limited group. Single N and P limitation, and serial P limitation were also observed, as well as negative responses to nutrient enrichment. Group-specific responses to nutrient enrichment were not reflected in the relative abundance of phytoplankton groups within the whole assemblage, due to the numerical dominance of pico-sized groups (cyanobacteria and eukaryotic picophytoplankton). Ambient nutrient ratios and concentrations did not predict phytoplankton nutrient limitation, given the different nutrient utilisation traits among phytoplankton functional groups. Therefore, nutrient ratios should not be used as indicators of nutrient limitation in eutrophication assessment.

2023-07Journal article

Open access

Short-term effects of climate change on Planktonic Heterotrophic Prokaryotes in a temperate Coastal Lagoon: Temperature Is good, ultraviolet radiation Is bad, and CO2 Is neutral

Publication . B. Barbosa, Ana; Mosley, Benjamin A.; M. Galvão, Helena; Domingues, Rita B.

Planktonic heterotrophic prokaryotes (HProks) are a pivotal functional group in marine ecosystems and are highly sensitive to environmental variability and climate change. This study aimed to investigate the short-term effects of increasing carbon dioxide (CO2), ultraviolet radiation (UVR), and temperature on natural assemblages of HProks in the Ria Formosa coastal lagoon during winter. Two multi-stressor microcosm experiments were used to evaluate the isolated and combined effects of these environmental changes on HProk abundance, production, growth, and mortality rates. The isolated and combined effects of increased CO2 on HProks were not significant. However, HProk production, cellular activity, instantaneous growth rate, and mortality rate were negatively influenced by elevated UVR and positively influenced by warming. Stronger effects were detected on HProk mortality in relation to specific growth rate, leading to higher HProk net growth rates and abundance under elevated UVR and lower values under warming conditions.

2023-10-14Journal article

Open access

Short-term effects of winter warming and acidification on phytoplankton growth and mortality: more losers than winners in a temperate coastal lagoon

Publication . Domingues, Rita B.; Barreto, Marcelle; Brotas, Vanda; Galvão, Helena M.; Barbosa, Ana B.

Changes in temperature and CO2 are typically associated with climate change, but they also act on shorter time scales, leading to alterations in phytoplankton physiology and community structure. Interactions among stressors may cause synergistic or antagonistic effects on phytoplankton dynamics. Therefore, the main goal of this work is to understand the short-term isolated and interactive effects of warming and high CO2 on phytoplankton nutrient consumption, growth, production, and community structure in the Ria Formosa coastal lagoon (southern Portugal). We performed microcosm experiments with temperature and CO2 manipulation, and dilution experiments under temperature increase, using winter phytoplankton assemblages. Phytoplankton responses were evaluated using inverted and epifluorescence microscopy. Overall, phytoplankton growth and microzooplankton grazing on phytoplankton decreased with warming. Negative antagonist interactions with CO2 alleviated the negative effect of temperature on phytoplankton and cryptophytes. In contrast, higher temperature benefited smaller-sized phytoplankton, namely cyanobacteria and eukaryotic picophytoplankton. Diatom growth was not affected by temperature, probably due to nutrient limitation, but high CO2 had a positive effect on diatoms, alleviating the effect of nutrient limitation. Results suggest that this winter phytoplankton assemblage is well acclimated to ambient conditions, and short-term increases in temperature are detrimental, but can be alleviated by high CO2.

2021Journal article

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