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- Temperature and salinity regimes in a shallow, mesotidal lagoon, the Ria Formosa, PortugalPublication . Newton, Alice; Mudge, S.In a recent study of the mesotidal Ria Formosa, a coastal lagoon in southern Portugal, water temperature in the channels ranged from 12 C in winter to 27 C in summer and salinity from 13 to 36.5, although much higher values were observed in saltpans. Conditions in the Ria Formosa were not homogeneous despite a large tidal exchange of water; the inner channels of the Ria Formosa were brackish in winter but hypersaline in summer. Water in inner areas of lagoon had significantly different temperature and salinity characteristics compared to the inflowing coastal water, both in winter and in summer. Areas with these differences in temperature and salinity were detectable both at low water and at high water neaps. Deterioration of water quality is therefore more probable in these areas. The waters went through a complex heating and cooling cycle in summer with diurnal difference of 6 C and 2 in temperature and salinity, respectively. The lack of freshwater input and high insolation meant the outflowing water of the lagoon was more saline that the inflowing coastal waters. In summer, the temperature controlled density with the least dense waters also being the most saline, whereas in winter salinity was the major density controlling parameter. The effects of these freshwater inputs were localised to the vicinity of the Gila˜o River. No evidence was found of persistent or widespread temperature or salinity stratification in the Ria Formosa and so this shallow lagoon appears to be vertically well mixed. Vertical mixing does not allow a dense, stagnant, bottom layer of water to form that would aggravate a deterioration of water quality. The net effect of these processes is a parcel of water that moves through the lagoon with minimal dilution and potentially receiving waste discharges.
- Contribution of remote sensing products to the management of offshore aquaculture at Sagres, SW PortugalPublication . Icely, John; Moore, Gerald; Danchenko, Sergei A.; Goela, Priscila; Cristina, Sónia; Zacarias, Marielba; Newton, AliceRemote sensing can address important issues affecting offshore aquaculture such as prediction of Harmful Algal Blooms. In situ data for nutrients, chlorophyll a (Chla) and phytoplankton community from a site for long-line aquaculture for bivalves off the SW coast of Portugal has been compared during a period of upwelling with remote sensing data for Chla, sea surface temperature, salinity, direction and intensity of both currents and winds. On the 11th February the in situ nutrients levels were high and the Chla was low, but by the 12th March the converse was the situation. The evolution of this event could be followed by combining remote sensing and model data from a variety of open source web sites made available by the Earth Observation provider that demonstrated clearly the lags between the physical forcings promoting upwelling and the eventual blooms of phytoplankton.
- Assessing the effectiveness of management measures in the Ria Formosa coastal lagoon, PortugalPublication . Newton, Alice; Cañedo-Argüelles, Miguel; March, David; Goela, Priscila; Cristina, Sónia; Zacarias, Marta; Icely, JohnThe Ria Formosa is an important transitional and coastal lagoon on the south coast of Portugal that provides valuable ecosystem services. The lagoon is a protected area under national and international conventions. There is a great potential for Blue Growth sectors, such as aquaculture and coastal tourism, but these rely on good water quality. European environmental legislation, such as the Water Framework Directive, requires member states, such as Portugal to implement management measures if a surface water body is not of good ecological status. This work addresses the effectiveness of management measures, such as wastewater treatment plant implementation and dredging, on the water quality of the Ria Formosa coastal lagoon system. This is an important social-ecological issue, since management measures can be very expensive. The ecological status of Ria Formosa was evaluated, according to the physico-chemical and biological quality elements of the Water Framework Directive. The main indicators were the physico-chemical quality elements of nutrient and oxygen condition, and the biological quality element chlorophyll a, as a proxy for phytoplankton biomass, under the Water Framework Directive. The data for these quality elements from the Ria Formosa were analyzed for consistency with the classification for the Water Framework Directive water bodies. The data after the implementation of management measures was compared with historical data to evaluate if these measures had been effective. The relation between nutrient pressures, meteorological and hydrological conditions was addressed, especially rainfall and runoff. Results showed a decrease in nutrient concentration after the management interventions, despite the increase of population and intensifying agriculture in the catchment. The Ecological Status is spatially variable with an overall moderate status, indicating the need for further management measures. There is a significant reduction in nutrient pressure on the lagoon during drought years. This indicates that climate change may alter the structure and function of the lagoon in the future.
- MERIS phytoplankton time series products from the SW Iberian Peninsula (Sagres) using seasonal-trend decomposition based on loessPublication . Cristina, Sónia; Cordeiro, Clara; Lavender, Samantha; Goela, Priscila; Icely, John; Newton, AliceThe European Space Agency has acquired 10 years of data on the temporal and spatial distribution of phytoplankton biomass from the MEdium Resolution Imaging Spectrometer (MERIS) sensor for ocean color. The phytoplankton biomass was estimated with the MERIS product Algal Pigment Index 1 (API 1). Seasonal-Trend decomposition of time series based on Loess (STL) identified the temporal variability of the dynamical features in the MERIS products for water leaving reflectance ((w)()) and API 1. The advantages of STL is that it can identify seasonal components changing over time, it is responsive to nonlinear trends, and it is robust in the presence of outliers. One of the novelties in this study is the development and the implementation of an automatic procedure, stl.fit(), that searches the best data modeling by varying the values of the smoothing parameters, and by selecting the model with the lowest error measure. This procedure was applied to 10 years of monthly time series from Sagres in the Southwestern Iberian Peninsula at three Stations, 2, 10 and 18 km from the shore. Decomposing the MERIS products into seasonal, trend and irregular components with stl.fit(), the (w)() indicated dominance of the seasonal and irregular components while API 1 was mainly dominated by the seasonal component, with an increasing effect from inshore to offshore. A comparison of the seasonal components between the (w)() and the API 1 product, showed that the variations decrease along this time period due to the changes in phytoplankton functional types. Furthermore, inter-annual seasonal variation for API 1 showed the influence of upwelling events and in which month of the year these occur at each of the three Sagres stations. The stl.fit() is a good tool for any remote sensing study of time series, particularly those addressing inter-annual variations. This procedure will be made available in R software.
- Modeling the influence of rutrophication and redox conditions on mercury cycling at the sediment-water interface in the Berre LagoonPublication . Pakhomova, Svetlana; Yakushev, Evgeniy; Protsenko, Elizaveta; Rigaud, Sylvain; Cossa, Daniel; Knoery, Joel; Couture, Raoul-Marie; Radakovitch, Olivier; Yakubov, Shamil; Krzeminska, Dominika; Newton, AliceThis study presents a specifically designed Mercury module in a coupled benthic-pelagic reactive-transport model - Bottom RedOx Model (BROM) that allows to study mercury (Hg) biogeochemistry under different conditions. This module considers the transformation of elemental mercury (Hg(O)), divalent mercury (Hg(II)) and methylmercury (MeHg). The behavior of mercury species in the model is interconnected with changes of oxygen, hydrogen sulfide, iron oxides, organic matter, and biota. We simulated the transformation and transport of Hg species in the water column and upper sediment layer under five different scenarios, combining various levels of oxygenation and trophic state in the Berre lagoon, a shallow eutrophic lagoon of the French Mediterranean coast subjected to seasonal anoxia. The first scenario represents the conditions in the lagoon that are compared with experimental data. The four other scenarios were produced by varying the biological productivity, using low and high nutrient (N and P) concentrations, and by varying the redox conditions using different intensity of vertical mixing in the water column. The results of the simulation show that both oxidized and reduced sediments can accumulate Hg, but any shifts in redox conditions in bottom water and upper sediment layer lead to the release of Hg species into the water column. Eutrophication and/or restricted vertical mixing lead to reducing conditions and intensify MeHg formation in the sediment with periodic release to the water column. Oxygenation of an anoxic water body can lead to the appearance of Hg species in the water column and uptake by organisms, whereby Hg may enter into the food web. The comparison of studied scenarios shows that a well-oxygenated eutrophic system favors the conditions for Hg species bioaccumulation with a potential adverse effect on the ecosystem. The research is relevant to the UN Minimata convention, EU policies on water, environmental quality standards and Mercury in particular.
- Circles of coastal sustainability and emerald growth perspectives for transitional waters under human stressPublication . Povilanskas, Ramūnas; Jurkienė, Aistė; Dailidienė, Inga; Ernšteins, Raimonds; Newton, Alice; Leyva Ollivier, María EstherEmerald Growth is an overarching sustainable development framework for transitional waters situated between rivers and open sea. The emphasis on connectivity and ecosystem-based management as the underlying principles differentiates Emerald Growth from conventional approaches to managing transitional waters. The study's primary objective was to conjoin the Emerald Growth concept with the Coastal Circles of Sustainability methodology, an analytical framework to assess indicators of critical processes determining the sustainability of the coastal zone. We hypothesized that applying the CCS is an apt approach to categorizing the Emerald Growth's aspects using Lake Liepaja, a fresh-to-brackish water lagoon on Latvia's Baltic Sea coast, as a case study. Based on the document scoping findings on Lake Liepaja's hydrology, ecology, biodiversity, nature conservation, and management, we addressed the knowledge gaps through the field survey, 4 workshops, and 18 in-depth semi-structured interviews with local stakeholders. The research results show that the challenging socio-economic situation is a crucial obstacle to Emerald Growth in the Lake Liepaja area. Subsistence salary and Housing affordability (Economic Welfare aspect), Population growth and Aging population (Demographic aspect), and Traditional practices (Identity aspect) received the lowest sustainability score (Bad). The results imply that considering the Emerald Growth conditions and drivers for transitional waters worldwide, finding a 'one-fits-all' recipe to ensure their sustainability is impossible. The decision-makers, stakeholders, and external experts agreed that for Lake Liepaja, the priority was to bring back to nature part of the polder system, clean the bottom sediments from Soviet-era pollutants, and enhance the transboundary cooperation with Lithuania. These measures would set the right conditions for future Emerald Growth in the area.
- Eutrophication in transitional waters: an overviewPublication . Zaldívar, José-Manuel; Cardoso, Ana Cristina; Viaroli, Pierluigi; Newton, Alice; Wit, Rutger; Ibañez, Carles; Reizopoulou, Sofia; Somma, Francesca; Razinkovas, Arturas; Basset, Alberto; Holmer, Marianne; Murray, NicholasDespite their ecological and economic importance, Transitional Waters (TWs) have fallen behind all the other water categories in respect to the implementation of the Water Framework Directive (WFD) and further, pose some interpretation problems in other existing Water Directives. The problems faced by TWs concerning the implementation of WFD are mainly related to their characteristics, including: the high spatio-temporal variability, the fast response time to perturbations, their high productivity, the fact that primary production in these systems is normally not dominated by phytoplankton, their high socio-economic importance with a long historical tradition, and the strong anthropogenic pressures which exists in these systems. The present review attempts to bring together the main elements characterizing TWs and to identify the current understanding of the process of eutrophication and the problems this raises in establishing reference conditions, in view of the need of implementing the WFD. It is thus necessary to reach agreement on working definitions of TWs that can form the basis for the development of methodologies permitting the establishment of reference conditions; gain an understanding of the processes of eutrophication and the drivers and pressures that play a major role in their evolution; and investigate the use of indicators susceptible of accurately reflecting the ecological quality status of these types of water, as required by the WFD.
- Temporal and spatial variation of phytopigments in the Western part of the Ria Formosa lagoon, Southern PortugalPublication . Pereira, M.; Icely, John; Mudge, S.; Newton, Alice; Rubina, R.The spatial and temporal variation of phytoplankton pigments in the western part of Ria Formosa, Portugal, was investigated between September 2000 and July 2002. Sampling stations included the ocean boundary (Anc˜ao inlet) and two different landward boundary situations: 1) the shallow westernmost “blind end” of the lagoon (Ponte) and 2) near a main sewage outlet (Ramalhete). Nutrient concentrations were higher during the first year of sampling but were lower than those recorded in previous studies. This decrease in the concentration of nutrients was possibly the result of the 1997 relocation of the Anc˜ao inlet, which allowed better water circulation in the lagoon. Throughout this study, concentrations of chlorophyll a determined by high-performance liquid chromatography were consistently low. Inter-annual variability in the pattern of chlorophyll a concentration was observed in the form of a bimodal peak (spring/summer and autumn) between September 2000 and June 2001 and more uniformconcentrations from September 2001 until July 2002. Principal component analysis of the concentrations of all pigments did not indicate any spatial- or tidal-related variations but did show that pigment concentrations varied over time. Partial least squares analysis corroborated this temporal shift of the phytoplankton pigment abundance and composition and showed that these shifts could be linked to certain environmental variables. Fucoxanthin was the dominant accessory pigment and was strongly correlated with chlorophyll a. Other marker pigments present in lower concentrations included chlorophyll b, 19′-hexanoyloxyfucoxanthin, neoxanthin, alloxanthin, diadinoxanthin, lutein, zeaxanthin, and beta-carotene. PLS analysis was used to infer the dominant phytoplanktonic groups in the lagoon. This analysis established that diatoms and other algal groups with a similar pigment profile dominated the phytoplankton community throughout the year. Cryptophytes were the second most abundant group in the lagoon. The remaining groups, including dinoflagellates, cyanophytes, and chlorophytes, contributed much less to the total algal biomass (generally <10%).
- Using remote sensing as a support to the implementation of the European Marine Strategy Framework Directive in SW PortugalPublication . Cristina, Sónia; Icely, John; Goela, Priscila; Angel DelValls, Tomás; Newton, AliceThe exclusive economic zones (EEZ) of coastal countries are coming under increasing pressure from various economic sectors such as fishing, aquaculture, shipping and energy production. In Europe, there is a policy to expand the maritime economic sector without damaging the environment by ensuring that these activities comply with legally binding Directives, such as the Marine Strategy Framework Directive (MSFD). However, monitoring an extensive maritime area is a logistical and economic challenge. Remote sensing is considered one of the most cost effective, methods for providing the spatial and temporal environmental data that will be necessary for the effective implementation of the MSFD. However, there is still a concern about the uncertainties associated with remote sensed products. This study has tested how a specific satellite product can contribute to the monitoring of a MSFD Descriptor for "good environmental status" (GES). The results show that the quality of the remote sensing product Algal Pigment Index 1 (API 1) from the MEdium Resolution Imaging Spectrometer (MERIS) sensor of the European Space Agency for ocean colour products can be effectively validated with in situ data from three stations off the SW Iberian Peninsula. The validation results show good agreement between the MERIS API 1 and the in situ data for the two more offshore stations, with a higher coefficient of determination (R-2) of 0.79, and with lower uncertainties for the average relative percentage difference (RPD) of 24.6% and 27.9% and a root mean square error (RMSE) of 0.40 and 0.38 for Stations B and C, respectively. Near to the coast, Station A has the lowest R-2 of 0.63 and the highest uncertainties with an RPD of 112.9% and a RMSE of 1.00. It is also the station most affected by adjacency effects from the land: when the Improved Contrast between Ocean and Land processor (ICOL) is applied the R-2 increases to 0.77 and there is a 30% reduction in the uncertainties estimated by RPD. The MERIS API 1 product decreases from inshore to offshore, with higher values occurring mainly between early spring and the end of the summer, and with lower values during winter. By using the satellite images for API 1, it is possible to detect and track the development of algal blooms in coastal and marine waters, demonstrating the usefulness of remote sensing for supporting the implementation of the MSFD with respect to Descriptor 5: Eutrophication. It is probable that remote sensing will also prove to be useful for monitoring other Descriptors of the MSFD.
- Temporal and spatial variability of microphytobenthos in a shallow lagoon: Ria Formosa (Portugal)Publication . Brito, Ana; Newton, Alice; Tett, Paul; Fernandes, TeresaMicrophytobenthos (MPB) are an important, yet highly variable, component of productive shallow systems and intertidal areas. Samples were collected from Ria Formosa, Portugal, to assess the temporal and spatial variability of microphytobenthic chlorophyll in two types of intertidal sediment: mud and sand. Chlorophyll pigments were measured spectrophotometrically after freeze-drying and extraction into an acetone–water mixture. Time-series of superficial chlorophyll measured at two sites during 2006–2007 showed no obvious seasonal peaks. A truncated Fourier series was fitted to the time-series data. Seasonality was very weak: only 5% of the estimated total variance could be explained by annual cycle components up to 3 year 1, while 25% was explained by waves with periods from 14 to 91 days. The residual error of the Fourier series was partitioned into within-day variance (61%) and other components (9%). The within-day variation was made up of roughly equal contributions from: (i) variability associated with sampling within-sites; and (ii) differences between-sites. There were no significant correlations between MPB chlorophyll and tidal range, wind speed, solar irradiance, water temperature and salinity and water nutrient concentrations. Sediment type was once more confirmed to be a key factor to MPB spatial variability. These results are discussed in relation to processes controlling the distribution of benthic microalgae in Ria Formosa, and their implications considered in relation to on-going work to understand and model the role of microphytobenthos in eutrophication in such water bodies.