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Developing a Citizen Science Approach to Monitor Stranded Marine Plastics on a Remote Small Island in Indonesia
Full text linkMarine plastics stranded on the coastlines of remote small islands threaten both the ecological integrity of local ecosystems and communities’ well‐being. However, despite the growing quantities of stranded plastics in these locations, the remote nature of these sites renders monitoring and intervention efforts difficult to undertake. Within this context, we developed a citizen science approach to monitor stranded marine plastics in collaboration with villagers living on a remote small island in Indonesia. This study reports the co‐development and application of an approach that can be used and maintained independently by remote coastal communities. In the monitoring stage, the participants quantified both the weight and composition of stranded marine debris on a beach located in their village for a 4‐week period from late May to mid‐June 2021. The results revealed that the weekly accumulation of stranded marine debris on the beach was 3.97 kg/m 2 , with 58% categorized as plastics. The stranded plastics sampled in this study were sorted and collected for recycling, estimated to provide a total economic value of 91,700 Indonesian Rupiahs (USD 5.84), or equivalent to 12.77% of the average monthly household income in the area. The citizen science activities indicated that the local villagers were capable of operating the designed monitoring system effectively, with the added benefits of supplementary earnings from recycling. An independently operated monitoring approach combined with collection efforts for recyclable items is important as remote islands have to manage increasing quantities of stranded marine debris despite the lack of an adequate local waste management system
Positive controls with representative materials are essential for the advancement of microplastics research
No full textReporting accurate microplastics concentrations across environmental matrices is imperative for robust monitoring and regulation. However, recovering microplastics from complex matrices, such as soils and sediments, is hugely challenging. Numerous methods have been published to facilitate microplastics extraction from such matrices, but these protocols typically lack validation of microplastic recovery efficiency. We argue that environmentally realistic microplastic recovery rate experiments must be utilized consistently to increase the validity of microplastics pollution research, particularly for studies focused on complex matrices. Here, we outline the importance of harmonized recovery rate tests and demonstrate this experimentally using saltmarsh sediments as a case study. Building-upon established protocols, an iterative approach was used to test the recovery of four types of environmentally relevant microplastics: polypropylene (PP) fragments, polyethylene (PE) films, polyamide (PA) fibers and polyester (PET) fibers ranging in size from 180 to 1060 μm. For protocols attaining > 50% microplastic recovery, these methods were optimized to attain maximal recovery of all plastic types, and optimal methods replicated to determine precision. Most methods demonstrated efficient removal of organic and inorganic materials with reasonable recovery rates for fragments and films, but many methods failed to sufficiently recover fibers. This further underscores the need for environmentally representative reference microplastics for method validation. Owing to the differences and complexities across environmental matrices, the standardization of microplastic extraction methods is unlikely. Therefore, recovery rate experiments with representative reference microplastics should be a requirement to increase quality, harmonization, and comparability
Pride and prejudice of the anthropocene coasts
Full text linkThis short communication highlights the emergence of complex design coastal reclamation for high-end property
development, which we term ‘prestige reclamation’. The prestige reclamation planiforms are typically symbols,
showcasing national pride, or highly crenulate designs to maximise the perimeter: area ratios, ensuring the
greatest waterfront potential on the newly constructed artificial shores. Numerous questions arise as these new
coasts are built: 1) what is the ecological impact of such developments, and does it differ from existing industrial
and agricultural reclamations; 2) how might the complex designs affect the water quality within and around the
reclamations; and finally 3) for these developments geared towards high end real-estate, recreation and tourism,
how have the developments affected people living in and near these new coasts? We recognise that we stand at a
crucial point in time to study these prestige reclamations, with rising sea levels, a global biodiversity crisis and a
tempestuous financial climate. Therefore, this topic demands further attention and global collaboration to
collectively study impact and provide alternatives to the growing demand of coastal lan
A compilation of surface inherent optical properties and phytoplankton pigment concentrations from the Atlantic Meridional Transect
Full text linkIn situ measurements of particulate inherent optical properties (IOPs) – absorption (ap(λ)), scattering (bp(λ)), and beam attenuation (cp(λ)) – are crucial for the development of optical algorithms that retrieve biogeochemical quantities such as chlorophyll a, particulate organic carbon (POC), and total suspended matter (TSM). Here we present a compilation of particulate absorption–attenuation spectrophotometric data measured underway on nine Atlantic Meridional Transect (AMT) cruises between 50° N and 50° S from 2009–2019. The compilation includes coincident high-performance liquid chromatography (HPLC) phytoplankton pigment concentrations, which are used to calibrate transects of total chlorophyll a (Tot_Chl_a) concentrations derived from the ap(λ) line-height method. The IOP data are processed using a consistent methodology and include propagated uncertainties for each IOP variable, uncertainty quantification for the Tot_Chl_a concentrations based on HPLC match-ups, application of consistent quality-control filters, and standardization of output data fields and formats. The total IOP dataset consists of ∼310 000 measurements at a 1 min binning (∼270 000 hyper-spectral) and >700 coincident HPLC pigment surface samples (∼600 of which are coincident with hyper-spectral IOPs). We present the geographic variation in the IOPs, HPLC phytoplankton pigments, and ap-derived Tot_Chl_a concentrations which are shown to have uncertainties between 8 % and 20 %. Additionally, to stimulate further investigation of accessory pigment extraction from ap(λ), we quantify pigment correlation matrices and identify spectral characteristics of end-member ap(λ) spectra, where accessory pigment groupings are present in higher concentrations relative to Tot_Chl_a. All data are made publicly available in SeaBASS and NetCDF formats via the following links: https://seabass.gsfc.nasa.gov/archive/PML/AMT (Jordan et al., 2025a) and https://doi.org/10.5281/zenodo.12527954 (Jordan et al., 2024)
Marine heatwaves as hot spots of climate change and impacts on biodiversity and ecosystem services
No full textIntensifying marine heatwaves (MHWs) are pervasive and destructive manifestations of anthropogenic climate change. Over the past two decades, MHWs have driven biological, ecological and socioeconomic change in almost all oceans and seas. In this Review, we assess the impacts of MHWs on marine organisms and the benefits they provide to people, highlight knowledge gaps and consider opportunities to mitigate MHW impacts. Globally, MHWs have become increasingly intense and frequent, and result in mortality or movement of species when acute temperature thresholds are exceeded. Vulnerability and resilience to MHWs vary among species, but these mortality events have been prominent for habitat-forming foundation species such as corals, kelp and seagrass, causing many cascading indirect impacts on ecosystem functioning and biodiversity. Poleward species shifts produce novel and complex species interactions and altered ecosystem functions, which have considerable consequences for people and their livelihoods. Reducing greenhouse gas emissions remains essential and urgent to address impacts long term, but increases in MHW intensities and duration will be unavoidable and prominent for the foreseeable future. As such, closing the current knowledge gaps around MHWs and their impacts on biodiversity, as well as proactive management strategies, are urgently needed to mitigate further damage to ecosystems and people, and to build resilience into the futur
Nitrogen status exerts dynamic control over phosphorus sensing and acquisition via PSR1 in colimited marine diatoms
No full textNutrient availability controls phytoplankton growth in aquatic ecosystems globally. Phytoplankton frequently experience a limiting supply of multiple nutrients simultaneously (colimitation). Ocean warming is predicted to exacerbate marine nutrient limitation. Yet, how phytoplankton adapt their physiology and regulate responses to colimitation is poorly understood. Here, we show that when the crucial macronutrients nitrogen (N) and phosphorus (P) colimit growth of globally abundant phytoplankton, the diatoms, cellular resources are diverted to prioritize N uptake over P sensing and acquisition. Regulatory mechanisms for responding to fluctuating P supply, including Phosphate Starvation Response 1 (PSR1) and P-resupply sensing via Ca2+ signaling, are strictly nitrate dependent. Further, P-Ca2+ signaling is impaired in psr1 mutants, suggesting that PSR1 is necessary for this response and coordinates adaptations to colimitation. Our study demonstrates a hierarchy of resource allocation during colimitation that points to N starvation mechanisms overriding those of P and could lead to N-P colimitation being masked in many marine ecosystems
Seasonal patterns and multidecadal trends in phytoplankton functional groups in the Benguela upwelling system off Namibia
Full text linkUnderstanding the response of phytoplankton to climate change is crucial for predicting shifts in marine ecosystems. Despite the Benguela being the world's most productive eastern boundary upwelling system, the distribution and susceptibility of its phytoplankton functional groups (PFGs) to climate change remain poorly understood. Here, we use 20 years (2003−2022) of daily MODIS-Aqua satellite data to uncover distinct spatial, seasonal and multidecadal trends in key PFGs (diatoms, dinoflagellates, flagellates, coccolithophores). PFGs exhibit strong regional and seasonal variability in their Spatial Extent and Frequency of dominance, with evidence of niche conditions favoring particular PFGs. Multidecadal trends reveal strong spatial variability in PFG adjustments, which are closely aligned with major upwelling cells. Some cells show increasing diatom dominance coupled with declines in coccolithophores, dinoflagellates and flagellates, while others exhibit the opposite trend. Seasonal transitions are also evident, with diatom-to-dinoflagellates shifts in Summer and enhanced diatom dominance in Autumn. Overall, PFGs increased in Spatial Extent and Frequency of dominance at distinct seasonal timings, except for declining coccolithophores. The link between alongshore equatorward winds and PFG trends strongly suggests an altered nutrient supply-driven response. Diatoms, significant carbon exporters, exhibit pronounced adjustments, highlighting their sensitivity to environmental changes. These findings are indicative of potential impacts on biogeochemical cycling and higher trophic levels, affecting carbon export and marine services. These insights provide a critical foundation for identifying climate-sensitive regions and seasonal windows of ecological vulnerability, supporting the development of early warning systems for adaptive conservation efforts
An innovation of two established methods for monitoring water colour and clarity: participatory science using the mini- and midi- secchi disks
Full text linkMeasurements of water colour and clarity are used to track the environmental status of lakes, estuaries and oceans. The oldest standardised methods for measuring water clarity and colour are the Secchi disk and Forel-Ule colour scale. Both techniques were developed in the 19th century and require use of the human eye. Despite the advent of optoelectronic-based sensing, these visual methods are still used today, owing to their sensitivity, affordability, simplicity and long history of use. Recently, a hand-held device was developed for measuring the Secchi depth and Forel-Ule colour (presented in two formats, named the mini- and midi-Secchi disk). Designed to be small, light and convenient-to-use, it is well suited for participatory science projects that involve monitoring water colour and clarity. To date, over 900 mini- and midi-Secchi disks have been distributed to citizens and scientists, primarily through six projects, with data mostly transferred via mobile phone applications to data servers and dashboards. In this paper, we describe the methods used in the projects and show some characteristics of the datasets collected so far. We showcase how the device can be used for scientific applications, such as verifying satellite data products, gaining new scientific insights, and supporting public engagement and education. Finally, we provide suggestions for methodological improvements and future developments
Darkening of the Global Ocean
Full text linkThe photic zones of the oceans—where sunlight and moonlight drive ecological interactions—are one of the most productive habitats on the planet and fundamental to the maintenance of healthy global biogeochemical cycles. Ocean darkening occurs when changes in the optical properties of the oceans reduce the depth to which sufficient light penetrates to facilitate biological processes guided by sunlight and moonlight. We analysed a 9 km resolution annual time series of MODIS Aqua's diffuse attenuation coefficient of light at 490 nm [ K d (490)] to quantify whether the oceans have darkened over the last 20 years and the impact of this on the depth of photic zones around the world. K d (490) increased across 75,341,181 km 2 (21%) of the global ocean between 2003 and 2022, resulting in photic zone depths reducing by more than 50 m across 32,449,129 km 2 (9%) by area. The depth of the photic zone has reduced by more than 10% across 32,446,942 km 2 (9%) of the global ocean. Our analysis indicates that ocean darkening is not restricted to coastal regions, but affects large swathes of the open ocean. A combination of nutrient, organic material and sediment loading near the coasts and changes in global ocean circulation are probable causes of increases in primary and secondary productivity that have reduced light penetration into surface waters. The implications of ocean darkening for marine ecology and the ecosystem services provided by the surface oceans are currently unknown but likely to be severe
Do whale sharks select for specific environments to give birth?
No full textNeonate whale sharks < 1.5 m in length are rarely encountered, with approximately 35 sightings recorded globally between 1970 and 2020. Although potentially pregnant females seem to frequent certain sites, parturition areas are unknown, and most neonates have been sighted opportunistically in offshore environments, suggesting nursery habitat may occur in remote parts of the ocean. Here, documented accounts of neonate whale sharks with corresponding locations were mapped in relation to oceanography to identify whether there are commonalities in where they occur. Results show that locations of neonate sightings coincide with permanent oxygen minimum zones (OMZs)—with associated high surface chlorophyll-a (Chl-a) and low oxygen at depth—more often than would be expected by random chance. Two main hypotheses are proposed to explain this apparent association: (i) adult female whale sharks selectively pup in waters adjacent to low oxygen regions offering a proximate refuge from oceanic predators as well as enhanced foraging opportunities, or that (ii) pupping occurs randomly in the open ocean but that OMZs restrict neonates to shallower surface waters where they are more frequently encountered by humans than elsewhere. Testing both hypotheses requires more data on the relationship between whale shark movement ecology and dissolved oxygen concentrations. As a first step, a model predicts the highest likelihood of neonates occurring in waters above OMZs, focussed around intermediate Chl-a regions at the boundaries of highly productive upwelling systems. These areas could be the focus of future, more targeted studies. Here, biologging devices measuring in situ oxygen concentrations will be useful for exploring how different life stages interact with OMZs, which are expanding due to climate-driven deoxygenation. What this might mean for neonate whale shark conservation in future warmer oceans remains an open questio