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- Strong upwelling conditions drive differences in species abundance and community composition along the Atlantic coasts of Morocco and Western SaharaPublication . Lourenco, Carla R.; Nicastro, Katy; McQuaid, Christopher D.; Krug, Lilian; Zardi, Gerardo I.Upwelling strongly influences the composition and dynamics of coastal communities by affecting species abundances, recruitment, dispersal and distribution. Coastal upwelling areas are key model regions to study the responses of coastal species to climate change because they are characterized by cooler water conditions and experience lower warming rates than adjacent regions, making them effective 'control' or refuge sites. This is particularly true for the benthic species of rocky shores in upwelling areas because they are sedentary, inhabit the interface between marine and terrestrial habitats, are exposed to extremely severe and variable environmental conditions and often live near their tolerance limits. We sampled roughly 2000 km of the Atlantic coast of Morocco and Western Sahara to assess the influence of upwelling cells on patterns of diversity and abundance of northern African rocky shore species. We recorded 186 taxa, providing clarification of the distribution of 141 algae and documenting nine new species records for Morocco and Western Sahara. The results emphasize the influence of upwelling on the abundance and distribution of these organisms. The contrast between non-upwelling and upwelling areas highlights the direct and indirect importance of water temperature in shaping these communities, pointing to the consequences of large-scale warming. Such warming is likely to threaten intertidal species that already live close to their thermal tolerance limits and are not buffered by the effects of upwelling.
- Unravelling region-specific environmental drivers of phytoplankton across a complex marine domain (off SW Iberia)Publication . Krug, Lilian; Platt, T.; Sathyendranath, S.; Barbosa, Ana B.Phytoplankton, the dominant marine primary producers, are considered to be highly sensitive indicators of ecosystem condition and change. The southwest area off the Iberian Peninsula (SWIP, NE Atlantic) is located in a biogeographical transition zone between temperate and subtropical waters, and classified as being very vulnerable to climate change. SWIP includes a variety of oceanic and coastal domains, under the influence of topographic irregularities, coastal upwelling and continental freshwater outflows, that collectively challenge the understanding of phytoplankton dynamics and controls. This study aimed to evaluate patterns in seasonal and interannual variability in phytoplankton and underlying environmental determinants within specific regions of SWIP, during a 15-year period (1997–2012), and to assess whether climate variability affects the regions in different ways. Empirical Orthogonal Function (EOF) analysis of satellite-retrieved sea surface chlorophyll-a concentration (Chl-a), acquired from the Ocean Colour Climate Change Initiative (OC-CCI), 4-km, 16-day resolution, was used to regionalize the study area. Region-specific Chl-a variability patterns and their linkages with environmental determinants were explored using Generalized Additive Mixed Models (GAMM). A set of local physical-chemical variables, derived from satellite and model data, and large-scale climate indices, were used as environmental variables. EOF analysis of Chl-a variability over the heterogeneous SWIP area identified nine coherent regions, with distinctive variability patterns (4 coastals, 2 slopes and 3 open-ocean regions). Region specific GAMM models explained between 32% and 82% of Chl-a variance, with higher explanatory power (N61%) for open ocean regions and coastal regions under increased riverine influence. Chl-a model predictors, as well as their effects, varied markedly among SWIP regions. However, climate-sensitive local environmental variables (sea surface temperature – SST and photosynthetically available radiation) emerged as the most influential general predictors overall, and large-scale climate indices showed significant but minor effects. Over oceanic SWIP regions, Chl-a (0.08–1.50 μg L−1) showed a uni-modal annual cycle, with increases during the mixed layer deepening and late-winter maxima, reflecting seasonal changes in SST and ocean stratification, and probably related to increased nutrient availability and/or decreased mortality. Over coastal regions south of 37°N, Chl-a (0.23–10 μg L−1) also benefited from riverine discharges, mostly during winter, and upwelling induced by zonal westerly winds, stronger during summer. Over the Portuguese west coast region, Chl-a (0.26–2.20 μg L−1) showed a uni-modal annual cycle, with summer maxima, associated with the stimulatory effects of meridional northerly winds and coastal upwelling that partially extended into slope waters. Chl-a interannual variability showed zonal differences within SWIP, with significant interannual patterns only for regions south of 37°N. Nonetheless, contrasting trends were detected in coastal (decline) and oceanic (increase) regions, possibly a consequence of between-region differences in the relative roles of nutrient and light limitation, corresponding to significant interannual increases in wind speed and mixed layer depth. Our study used a biologically-relevant objective regionalization of a heterogeneous area, to elucidate phytoplankton dynamics and controls. The region-specific associations observed between phytoplankton and multiple climate-sensitive environmental drivers over the SWIP area reinforce the role of phytoplankton as a strategic element for evaluating ecosystem responses to climate variability and change.
- Connections between upwelling patterns and phytoplankton variability under different coastal regimes in SW Iberia PeninsulaPublication . Krug, Lilian; Silvano, Kathleen M.; Barbosa, Ana B.; Domingues, Rita B.; Galvão, Helena M.; Luis, Joaquim; Platt, Trevor; Relvas, Paulo; Sathyendranath, ShubhaThe region off southwestern Iberia (NE Atlantic) encompasses a wide variety of oceanographic regimes, including differently (geographic) oriented coastal areas impacted by upwelling, riverine inputs and submarine groundwater discharge, submarine canyons and seamounts, and open ocean waters, thereby potentially promoting zone-specific phytoplankton dynamics. Overall, this heterogeneous region is classified as being very sensitive to climate change, and climate-driven alterations (e.g., sea surface warming, changes in upwelling patterns and intensity) have been recently reported for the area. The present study aims to understand the contribution of upwelling to seasonal and interannual variability of coastal phytoplankton, using a remote sensing-based approach. Phytoplankton variability was evaluated using satellite-derived chlorophyll-a (Chl-a), as a proxy for phytoplankton biomass, and primary productivity (PP). Chl-a were obtained from merged SeaWiFS (Seaviewing Wide Field-of-view Sensor), MeRIS (Medium Resolution Imaging Spectrometer) and MODIS-Aqua (Moderate-resolution Imaging Spectroradiometer) sensors at Globcolour portal. PP data at 9.25 km resolution were derived from Eppley’s Vertically Generalized Production Model, based on SeaWiFS and MODIS-Aqua and available at the Ocean Productivity site. Upwelling intensity was estimated using the difference in sea surface temperature (SST) between off and nearshore zones. Advanced Very-High Resolution Radiometer (AVHRR) 4 km SST were obtained from Pathfinder database. Other phytoplankton environmental drivers, such as local (e.g., river flow) and global (e.g., North Atlantic Oscillation - NAO) climate variables, were also analysed. The study area was divided into subareas differently impacted by upwelling and riverine flow, and satellitederived data was averaged for each zone. Seasonal and interannual variability covering a 14-year time series (1998- 2011) for each variable/region were explored. Chl-a at offshelf locations was significantly lower than coastal areas, and exhibited a fairly stable unimodal annual cycle, with maximum during March. Coastal locations displayed more variable annual patterns, with spring and summer Chl-a maxima, reflecting the impact of upwelling events and freshwater inputs. In respect to interannual variability, NAO index and coastal Chl-a were negative and significantly correlated, with 1-month lag. Chl-a interannual trends were also correlated to local climate variables, namely riverine flow for the easternmost coastal zone. The correlation between upwelling intensity and phytoplankton off SW Iberia is region-dependent being less strong within regions dominated by riverine influence.
- Patterns and drivers of phytoplankton phenology off SW Iberia: a phenoregion based perspectivePublication . Krug, Lilian; Platt, Trevor; Sathyendranath, Shubha; Barbosa, Ana B.Phytoplankton patterns, tightly linked to the dynamics of the ocean surface layer and its atmospheric forcing, have major impacts on ecosystem functioning and are valuable indicators of its response to environmental variability and change. Phytoplankton phenology and its underlying drivers are spatially variable, and the study of its patterns, particularly over heterogeneous regions, benefits from a delineation of regions with specific phenological properties, or phenoregions. The area Southwest off the Iberian Peninsula (SWIP, NE Atlantic) integrates a highly complex set of coastal and ocean domains that collectively challenge the understanding of regional phytoplankton phenology and related forcing mechanisms. This study aims to evaluate phytoplankton phenology patterns over the SWIP area, during an 18-year period (September 1997 – August 2015), using an objective, unsupervised partition strategy (Hierarchical Agglomerative Clustering – HAC) based on phenological indices derived from satellite ocean colour data. The partition is then used to describe region-specific phytoplankton phenological patterns related to bloom magnitude, frequency, duration and timing. Region-specific variability patterns in phenological indices and their linkages with environmental determinants, including local ocean physical-chemical variables, hydrodynamic variables and large scale climate indices, were explored using Generalized Additive Models (GAM). HAC analyses identified five coherent phenoregions over SWIP, with distinctive phytoplankton phenological properties: two open ocean and three coastal regions. Over the open ocean, a single, low magnitude and long bloom event per year, was regularly observed. Coastal phenoregions exhibited up to six short bloom events per year, and higher intra-annual and variability. GAM models explained 50–90% of the variance of all phenological indices except bloom initiation timing, and revealed that interannual patterns in phytoplankton phenology and their environmental drivers varied markedly among the five phenoregions. Over the oceanic phenoregions, large-scale climate indices (Eastern Atlantic Pattern, Atlantic Meridional Oscillation), mixed layer depth (MLD) and nitrate concentration preceding primary bloom events were influential predictors, reflecting the relevance of nutrient limitation. For the Coastal-Slope, a relatively more light-limited phenoregion, North Atlantic Oscillation and wind speed were more relevant, and bloom magnitude was also positively influenced by riverine discharge. This variable was a significant predictor of bloom frequency, magnitude and duration over the Riverine-influenced region. Over the Upwelling-influenced region, upwelling intensity and mean annual MLD showed stronger partial effects on phytoplankton phenology. Overall, our phenology-based unsupervised approach produced a biologically-relevant SWIP partition, providing an evaluation of the complexity of interactions between phytoplankton and multiple environmental forcing, particularly over coastal areas.
- Are submarine groundwater discharges affecting the structure and physiological status of rocky intertidal communities?Publication . Piló, David; Barbosa, Ana B.; Teodosio, Maria; Encarnação, J.; Miguel de Sousa Leitão, Francisco; Range, Pedro; Krug, Lilian; Cruz, J.; Chícharo, LuísThis study evaluated the impacts of submarine groundwater discharges (SGD) on a rocky intertidal community of South Portugal, during April-November 2011. Chlorophyll-a concentration was higher at the SGD site in respect to the Reference site. Epibenthic community structure differed between sites, with an increase in Chthamalus spp. and a decrease in macroalgae coverage at the SGD site. The abundance and body size of Mytilus galloprovincialis were consistently higher at the SGD site. During mid-spring, under potentially higher SGD and less favorable conditions for coastal phytoplankton, the ecophysiological condition of M. galloprovincialis and G. umbilicalis was also higher at the SGD site. These beneficial effects on filter-feeders and herbivores probably resulted from local increases in prey availability, supported by SGD-driven nutrient inputs. Conversely, P. depressa was not favoured by SGD, probably due to a lower dependency on algae as food. The analysis of epibenthic community structure and ecophysiological condition represents a promising approach to disentangle the ecological impacts of SGD on intertidal ecosystems.
- Ocean surface provinces off Southwest Iberia based on satellite remote sensingPublication . Krug, Lilian; Barbosa, Ana B.; Sathyendranath, ShubhaThis thesis aimed to partition the complex surface marine domain off Southwest Iberia Peninsula (SWIP), using satellite remote sensing, and use it to assess phytoplankton variability patterns and underlying environmental drivers (1997 – 2015). Three unsupervised partition strategies, based on distinct input databases and temporal representations, detected a variable number of partition units (regions, provinces) of singular environmental and phytoplankton patterns within SWIP. An abiotic-based partition delineated 12 dynamic Environmental Provinces (EPs) that alternated coverage dominance along the annual cycle. EP patterns were in general related to phytoplankton biomass, indicated by satellite chlorophyll-a concentration (Chl-a), and productivity, thus supporting the biological relevance of this abiotic-based partition. A static partition, based on the main variability modes of Chl-a, derived 9 Chl-a regions. Moreover, a static partition strategy synthesised phytoplankton phenological patterns over SWIP into 5 phenoregions, with coherent patterns of timing, magnitude and duration of blooms. The spatial distribution of EPs, Chl-a regions and phenoregions shared similarities, which can be considered the main spatial patterns of SWIP ocean surface. In general, the spatial arrangement of the partition units showed a separation between coastal and open ocean, a latitudinal division (ca. 36.5oN) over the open ocean and, over the coast and slope, the influence of coastal upwelling along the west Portuguese coast and Cape São Vicente, and of river discharge along the northeastern Gulf of Cadiz. The environmental drivers of phytoplankton varied across partition units. Water column stratification, riverine discharge and upwelling intensity were the most influential modulators, and large scale climate indices usually showed minor effects. Environmental variables, Chl-a and phenology showed significant seasonal variability patterns, varying across regions. Interannual patterns were more complex, and significant trends were mostly detected within the Gulf of Cadiz. Linkages between environmental variability and phytoplankton support their use as an indicator of ecosystem status and change.
- An integrated coastal ecosystem monitoring strategy: Pilot case in Naf-Saint Martin Peninsula, BangladeshPublication . Sarker, Subrata; Krug, Lilian; Islam, Kazi Mainul; Basak, Shyamal Chandra; Huda, A. N. M. Samiul; Hossain, Md. Shahadat; Das, Nabanita; Riya, Shashowti Chowdhury; Liyana, Eurida; Chowdhury, Gawsia WahidunnessaRapid population growth creating an excessive pressure on the marine environment and thus monitoring of marine ecosystem is essential. However, due to high technical and financial involvement, monitoring of coastal ecosystem is always challenging in developing countries. This study aims to develop an integrated coastal ecosystem monitoring system that combines scientific sampling, numerical model simulation and citizen science observations to monitor the coastal ecosystem of Bangladesh. This concept of integrated monitoring approach was piloted from January 2022 to April 2023 at the South East coastal zone of Bangladesh. Scientific sampling and numerical model simulations were performed for temperature and salinity data collection. Citizen science approach was employed to collect data on environmental conditions, fisheries, plankton, other marine resources, and plastic pollution. Numerical model simulations and citizen scientists observations of temperature and salinity showed good agreement with the scientifically collected data. In addition, citizen scientists observations on fisheries, plankton, other marine resources and plastic pollution were also in line with the existing database and previous studies. The proposed integrated monitoring approach presents a viable technique, creating a new avenue for coastal and marine ecosystem monitoring where infrastructural facilities are limited.
- Impact of the citizen science project COLLECT on ocean literacy and well-being within a north/west African and south-east Asian contextPublication . Severin, Marine I.; Akpetou, Lazare Kouame; Annasawmy, Pavanee; Asuquo, Francis Emile; Beckman, Fiona; Benomar, Mostapha; Jaya-Ram, Annette; Malouli, Mohammed; Mees, Jan; Monteiro, Ivanice; Ndwiga, Joey; Neves Silva, Péricles; Nubi, Olubunmi Ayoola; Sim, Yee Kwang; Sohou, Zacharie; Shau-Hwai, Aileen Tan; Woo, Sau Pinn; Zizah, Soukaina; Buysse, Ann; Raes, Filip; Krug, Lilian; Seeyave, Sophie; Everaert, Gert; Mahu, Edem; Catarino, Ana I.Plastic pollution is both a societal and environmental problem and citizen science has shown to be a useful tool to engage both the public and professionals in addressing it. However, knowledge on the educational and behavioral impacts of citizen science projects focusing on marine litter remains limited. Our preregistered study investigates the impact of the citizen science project Citizen Observation of Local Litter in coastal ECosysTems (COLLECT) on the participants' ocean literacy, pro-environmental intentions and attitudes, well-being, and nature connectedness, using a pretest-posttest design. A total of 410 secondary school students from seven countries, in Africa (Benin, Cabo Verde, Cote d'Ivoire, Ghana, Morocco, Nigeria) and Asia (Malaysia) were trained to sample plastics on sandy beaches and to analyze their collection in the classroom. Non-parametric statistical tests (n = 239 matched participants) demonstrate that the COLLECT project positively impacted ocean literacy (i.e., awareness and knowledge of marine litter, self-reported litter-reducing behaviors, attitudes towards beach litter removal). The COLLECT project also led to higher pro-environmental behavioral intentions for students in Benin and Ghana (implying a positive spillover effect) and higher well-being and nature connectedness for students in Benin. Results are interpreted in consideration of a high baseline in awareness and attitudes towards marine litter, a low internal consistency of pro-environmental attitudes, the cultural context of the participating countries, and the unique settings of the project's implementation. Our study highlights the benefits and challenges of understanding how citizen science impacts the perceptions and behaviors towards marine litter in youth from the respective regions.
- Ocean surface partitioning strategies using Ocean Colour Remote Sensing: a reviewPublication . Krug, Lilian; Platt, T.; Sathyendranath, S.; Barbosa, Ana B.The ocean surface is organized into regions with distinct properties reflecting the complexity of interactions between environmental forcing and biological responses. The delineation of these functional units, each with unique, homogeneous properties and underlying ecosystem structure and dynamics, can be defined as ocean surface partitioning. The main purposes and applications of ocean partitioning include the evaluation of particular marine environments; generation of more accurate satellite ocean colour products; assimilation of data into biogeochemical and climate models; and establishment of ecosystem-based management practices. This paper reviews the diverse approaches implemented for ocean surface partition into functional units, using ocean colour remote sensing (OCRS) data, including their purposes, criteria, methods and scales. OCRS offers a synoptic, high spatial-temporal resolution, multi-decadal coverage of bio-optical properties, relevant to the applications and value of ocean surface partitioning. In combination with other biotic and/or abiotic data, OCRS-derived data (e.g., chlorophyll-a, optical properties) provide a broad and varied source of information that can be analysed using different delineation methods derived from subjective, expert-based to unsupervised learning approaches (e.g., cluster, fuzzy and empirical orthogonal function analyses). Partition schemes are applied at global to mesoscale spatial coverage, with static (time-invariant) or dynamic (time-varying) representations. A case study, the highly heterogeneous area off SW Iberian Peninsula (NE Atlantic), illustrates how the selection of spatial coverage and temporal representation affects the discrimination of distinct environmental drivers of phytoplankton variability. Advances in operational oceanography and in the subject area of satellite ocean colour, including development of new sensors, algorithms and products, are among the potential benefits from extended use, scope and applications of ocean surface partitioning using OCRS.
- Putting training into practice: an alumni network global monitoring programPublication . Krug, Lilian; Sarker, Subrata; Huda, Samiul; Gonzalez-Silvera, Adriana; Edward, Akinnigbagbe; Berghoff, Carla; Naranjo, Christian; Mahu, Edem; López-Calderón, Jorge; Escudero, Luís; Tapia, Maria; Noernberg, Mauricio; Ahmed, Mohamed; Menon, Nandini; Betancur, StellaThe ocean benefits humankind by producing half of the global oxygen supply, absorbing a significant portion of atmospheric carbon dioxide, and providing us with food, transportation, and a means of livelihood. Nevertheless, human activities have been making the global ocean more acidic, warmer, and lower in oxygen (IPCC, 2021). Such changes and their impacts on ecosystems are highly variable, particularly in coastal areas where exchanges with the atmosphere and the land are more pronounced. The capacity to collect ocean observations is insufficient in many parts of the world, particularly in developing countries (IOC-UNESCO, 2020). This is linked not only to a dearth of funding and instrumentation but also to a lack of scientific personnel with the capacity to collect, analyze, and interpret oceanographic data. The Partnership for Observation of the Global Ocean (POGO) runs capacity development programs whose objectives are to develop key skills, capabilities, and capacities needed for worldwide ocean observations, and to nurture new generations of experts and leaders in ocean affairs (see Urban and Seeyave, 2021). Since 2004, the partnership between POGO and the Nippon Foundation (NF) has offered an extensive array of training programs to nearly 500 early career scientists from 74 countries, mainly with emerging economies. The NF-POGO Alumni Network for the Ocean (NANO) was created in 2010 as a means to keep track of trainees’ career progressions, maximize the benefits from the training received, and provide further opportunities for networking and collaboration. One of NANO’s major goals is to promote joint research activities among its members, ultimately applying ocean observations for societal benefit.