Ecosystem Structure Research Articles

Fostering Entrepreneurial Spirit Among Algerian Students: Analysis of the Results of Ministerial Decision 1275 at Annaba University

To connect universities with their economic and social environment and enhance wealth creation, the Algerian Ministry of Higher Education has implemented new measures to foster entrepreneurship among students. These measures include establishing university interfaces to support student projects and issuing Ministerial Decision 1275, which transforms graduation theses into practical, innovative projects. This study examines the efforts of Algerian universities in entrepreneurship and the impact of Ministerial Decision 1275 at Badji Mokhtar University in Annaba. Data from the 2022/2023 academic year indicates that this decision has stimulated students‘ entrepreneurial spirit, showcasing their potential to turn ideas into start-ups. However, the main challenge remains the adaptability of the external ecosystem, including investors and funding structures, to this new entrepreneurial dynamic.

First record of two invasive aquatic weeds Ludwigia repens (Onagraceae) and Myriophyllum aquaticum (Haloragaceae) in Poland

AbstractThe aquarium trade has contributed to the introduction of many invasive alien plant species that threaten the structure and functioning of aquatic ecosystems around the world. In this study, I present the first Polish record of Ludwigia repens (Onagraceae) and Myriophyllum aquaticum (Haloragaceae), two invasive alien aquatic plants cultivated in aquaria. The plants were found on the shores and in the waters of an artificial pond in Kraków, southern Poland, in 2024. The location and abundance of both species are documented, and their introduction pathway and naturalization potential are discussed. Moreover, since M. aquaticum belongs to the invasive alien species of European Union concern and requires rapid eradication, its occurrence was reported to the Kraków City Office, following Polish law.

A Review of Studies on the Effects of Anthropogenic Disturbances on Plant–Soil–Microorganism Interactions in Grassland Ecosystems: Based on Grazing and Tourism Perspectives

As the most widely distributed and largest terrestrial ecosystem in the world, grasslands play an important role in supporting global livestock production and maintaining ecosystem services. In light of the accelerated global socio-economic development and sustained population growth, grassland ecosystems are increasingly subjected to anthropogenic disturbances. However, there is a paucity of research examining the impact of such disturbances on plant–soil–microorganism interactions in grassland systems, particularly from the perspectives of grazing and tourism. Accordingly, this study presents a comprehensive analysis of the impacts of anthropogenic disturbance on grassland ecosystems over the past two decades, employing a dual perspective of grazing and tourism and utilizing econometric analysis of the existing literature through software such as CiteSpace. The results of this study demonstrate the following: (1) The current research focus is primarily concentrated in the fields of ecology and environmental sciences, particularly on the topics of plant diversity, abundance, and diversity, as well as the intensity of grazing. These areas may represent key development direction of future research. (2) The impact of anthropogenic disturbances on grassland ecosystems is primarily associated with grazing activities. Moderate grazing disturbances can facilitate the healthy development of grassland ecosystems. However, the intermediate disturbance hypothesis (IDH) may not fully account for the effects of grazing intensity on grassland ecology. At present, there is still a paucity of systematic research to determine the ecological indicators of grassland under a dual-disturbance scenario. It is recommended that future research be carried out to investigate the compound effects of trampling by tourism activities on plant–soil–microorganism interactions in grassland ecosystems. (3) The mutual feedback mechanism may represent a potential mechanism by which anthropogenic disturbances affect the coupled relationship between the plant, soil, and microbial systems in grassland ecosystems. Furthermore, the interaction among these three systems has the potential to exert direct or indirect impacts on the structure and function of grassland ecosystems in the context of disturbances. The present study aims to provide an overview of the structure and function of grassland ecosystems under anthropogenic disturbances. The objective is to identify a balance between the rational use of grassland and ecological protection under anthropogenic disturbance and to provide scientific reference for the sustainable use of grassland worldwide.

Integrating revised DPSIR and ecological security patterns to assess the health of alpine grassland ecosystems on the Qinghai–Tibet Plateau

Alpine grassland ecosystems on the Qinghai–Tibet Plateau (QTP) provide critical services but face threats from human activity and climate change. Ensuring ecosystem health is vital for sustainability and preserving ecosystem services and processes, especially in delicate ecosystems such as the Gannan alpine grasslands. However, there is currently a lack of a comprehensive model that integrates ecosystem structure, function, processes, and socioeconomic factors. This study proposes a comprehensive ecosystem health assessment approach that combines the revised driver–pressure–state–impact–response (DPSIR) framework with ecological security patterns (ESPs), overcoming the limitations of previous models that focused primarily on ecosystem structure without sufficiently addressing dynamic ecosystem processes. This method aims to diagnose the health of the Gannan alpine grasslands on the QTP from 2000 to 2020. We found that in the context of global climate change, the ecological health was maintained at a relatively high level (covering 75.41 % of the area) in most areas of Gannan, whereas lower levels (12.09 %), were found in the northern areas of Gannan and southwestern areas of Maqu likely resulting from higher livestock density, increased population density, and weaker landscape connectivity. The results of the driver analysis showed that livestock inventory (with an influence Q-value of 0.70) significantly affected the health of the Gannan alpine grassland ecosystem, suggesting that sustainable livestock management is essential for maintaining ecological corridor connectivity, protecting core zones and promoting regional sustainability.

Freeze–thaw processes correspond to the protection–loss of soil organic carbon through regulating pore structure of aggregates in alpine ecosystems

Abstract. Seasonal freeze–thaw processes alter soil formation and lead to changes in soil structure of alpine ecosystems. Soil aggregates are basic soil structural units and play a crucial role in soil organic carbon (SOC) protection and microbial habitation. However, the impact of seasonal freeze–thaw processes on pore structure and their impact on SOC fractions have been overlooked. This study characterized the pore structure and SOC fractions of soil aggregates of the unstable freezing period, stable frozen period, unstable thawing period and stable thawed period in typical alpine ecosystems via a dry-sieving procedure, X-ray computed tomography scanning and elemental analysis. The results showed that pore networks of 0.25–2 mm aggregates were more vulnerable to seasonal freeze–thaw processes than those of >2 mm aggregates. The freezing process promoted the formation of >80 µm pores of aggregates. The total organic carbon, particulate organic carbon and mineral-associated organic carbon contents of aggregates were high in the stable frozen period and dropped dramatically in the unstable thawing period, demonstrating that the freezing process was positively associated with SOC accumulation, while SOC loss featured in the early stage of thawing. The vertical distribution of SOC of aggregates was more uniform in the stable frozen period than in other periods. Pore equivalent diameter was the most important structural characteristic influencing SOC contents of aggregates. In the freezing period, the SOC accumulation might be enhanced by the formation of >80 µm pores. In the thawing period, pores of <15 µm were positively correlated with SOC concentration. Our results revealed that changes in pore structure induced by freeze–thaw processes could contribute to SOC protection of aggregates.

Changes in prey-predator interactions in an Arctic food web under climate change

Global warming affects marine ecosystems by changing environmental conditions, ecosystem structure, and ecosystem functioning. In parts of the Arctic, increased sea temperature and decreased sea ice have led to a poleward expansion of boreal species and increased their interactions with native Arctic species. To investigate and quantify the changing interactions in an Arctic marine food web under new environmental conditions, we studied the interactions between key prey fish species in the seasonally ice-covered parts of the Barents Sea: adult polar cod (Boreogadus saida) and capelin (Mallotus villosus) and one of the major predators in the system: Atlantic cod (Gadus morhua). For this, we compared the predictive performance of threshold models predicting the abundance of adult polar cod as a function of Atlantic cod. Each model was associated with a hypothesis describing prey-predator interactions in different environmental conditions defined by threshold values of summer sea-ice or capelin stock biomass. The best predictive model showed that the predation effect of Atlantic cod on polar cod was strongest in years of low summer sea ice cover and low capelin stock biomass. Our results exemplified that Arctic species such as polar cod may experience increased predation pressure under climate change from boreal species such as Atlantic cod. These effects depend, however, not only on changes in abiotic drivers of species distributions, but also on food-web interactions involving mid-trophic level species such as capelin.

The Impacts of Warming on Shallow and Deep‐Water Fisheries in New Zealand

AbstractClimate change is already impacting ecosystem composition and species distributions. Here we study two different, but equally valuable New Zealand fisheries (Tasman Bay and Golden Bay, and Chatham Rise), and the potential impacts of climate change on ecosystem structure. We use mizer, a size‐based multispecies modeling package, to simulate interacting fish species in each ecosystem. Utilizing therMizer, an extension of mizer which incorporates temperature effects on species' metabolic rate and aerobic scope, we implement historical climate data from the Fisheries and Marine Ecosystem Model Intercomparison Project (FishMIP). This enables us to recreate the historical time period of 1961–2010, deriving reasonable steady state biomasses closely matching past observations. We then carry out a controlled warming simulation experiment, allowing for temperature to remain steady or to increase for both ecosystems, both with and without fishing pressure. The shallower ecosystem of Tasman and Golden Bay has more thermally tolerant species and experiences an overall increase in community biomass under warming, whilst the deeper ecosystem of Chatham Rise suffers an overall decline. In addition, fishing has a stronger negative impact on the Chatham Rise community. Smaller bodied animals also tend to be more resilient, both to warming and fishing impacts. Despite differences in community responses, the majority of important fisheries suffer reduced yields under warming in both ecosystems. Issues raised during the incorporation of temperature effects include species' thermal tolerances and model calibration to data. This study facilitates ecosystem intercomparisons under climate change and offers insight into drivers of ecosystem responses.

Assessment of changes in the structure of the forest ecosystems for example sanitary woody plantations in the Steppe Dnipro

Assessment of changes in the structure of the forest ecosystems for example sanitary woody plantations in the Steppe Dnipro

Temperate Intertidal Ecosystems are Functionally Richer but More Vulnerable to Loss Than Tropical Ecosystems.

Gastropods are major contributors to a range of key ecosystem services on intertidal rock platforms, supporting trophic structure in both terrestrial and marine contexts and manipulating habitat complexity. However, the functional structure of these assemblages is rarely examined across broad spatial scales. Here, we describe patterns in gastropod functional diversity, redundancy and vulnerability to functional loss across a latitudinal gradient following the west coast of Australia (18° S-34° S). Specifically, we created a trait matrix based on six categorical traits for 186 gastropod species from 39 sites to examine how trait composition varied with latitude. We found there was no latitudinal gradient in either functional richness or distinctiveness despite clear gradients in species richness and taxonomic distinctiveness, which both increased towards the equator. We delineated two distinct functional bioregions, a temperate south (34° S-27° S) and a tropical north (24° S-18° S), and found that the temperate bioregion had greater functional richness and uniqueness but lower redundancy compared to the tropical bioregion. Our findings show that gastropod assemblages in the temperate bioregion are more vulnerable to functional loss as their functional entities are supported by fewer or even single species. Comparatively, the tropical bioregion reported higher redundancies, which could provide a buffer against future change. Understanding the functional structure of intertidal ecosystems is vital as gastropods face the uncertain impacts of coastal tropicalisation, range shifts and sea level rise.

Coming to the dark side: How does nitrogen eutrophication reshape the mixotrophic trade-off of osmo-mixotrophy in Ochromonas?

Increasing nitrogen level is one of the most serious environmental problems in global natural waters, disturbing the stability of function and structure of aquatic ecosystem. As important functional group, mixotrophs with plastic metabolism modes perform high adaptations under changing environments, potentially with positive biogeochemical consequences. Here we focus on the trophic plasticity of a model eukaryotic microorganism, mixotrophic Ochromonas under increasing nitrogen and tested the role of osmo-mixotrophy (= mixotrophy) on the physiology of Ochromonas. Results showed that nitrogen eutrophication significantly reduced the proportion of open PSII reaction centers of mixotrophic Ochromonas, and osmo-mixotrophic Ochromonas enhanced the relative contribution of organic carbon uptake with increasing nitrogen. Furthermore, genes involved in photosynthetic electron transfer and photosynthetic carbon fixation were down-regulated, and genes involved in energy metabolism were upregulated. These findings suggested that increasing nitrogen caused mixotrophic organisms to become more heterotrophic, which may bring unexpected impacts to the balance of photosynthesis and respiration within aquatic ecosystem.

Dryland fungi are spatially heterogeneous and resistant to global change drivers

AbstractFungi are considered particularly important in regulating the structure and function of dryland ecosystems, yet the response of dryland fungal communities to global change remains notably understudied. Without a clear understanding of how fungi respond to global change drivers, mitigation plans—required for biodiversity and ecosystem service conservation and restoration—are impossible to develop. In this study, we asked the following: (1) How does the fungal community respond to the individual and interactive effects of physical disturbance and drought in a heterogeneous dryland landscape comprised of drought‐adapted shrubs separated by adjacent open areas of soil? (2) What are the larger scale impacts of this response? We assessed fungal communities (using fungal‐specific DNA metabarcoding analyses) of surface soil samples in an in situ global change experiment that included disturbance and drought in a full factorial design in the northern extent of the Chihuahuan Desert. We found that the fungal community was spatially heterogenous and remarkably resistant to disturbance and drought. We also show that dryland soils harbor high shares of facultative pathogenic and obligately pathogenic fungal taxa, with several concerning taxa reaching high relative abundances under drought. Our results suggest that the fungal community is highly influenced by microclimatic conditions associated with the presence or absence of vegetation. Moreover, our results imply that the fungal community in our experiment was already adapted to the magnitude of stress imposed by two years of experimental disturbance and drought treatments. Overall, our study shows that the fungal community is spatially heterogeneous and resistant to global change drivers and houses many fungal species known for being stress tolerant and pathogenic.

Responses of vegetation low-growth to Extreme Climate Events on the Mongolian Plateau

Since the 21st century began, the frequency and intensity of extreme climate events have significantly increased globally, becoming a widely recognized phenomenon of global change. These extreme events, including droughts and heatwaves, have profound impacts on the structure and function of ecosystems. This study focuses on the Mongolian Plateau. It utilizes meteorological and remote sensing vegetation data, combined with consistency and sensitivity analyses. These approaches aim to provide an in-depth understanding of the relationship between various extreme climate events and vegetation low-growth. The study found that extreme drought and extreme heat events are the primary drivers affecting vegetation low-growth on the Mongolian Plateau. The analysis results indicate that the sensitivity of vegetation to these extreme climate events is regulated by regional hydrothermal conditions, with vegetation in long-term drought areas being more susceptible to the suppression of extreme drought, while humid areas exhibit some resistance. As the temperature gradient increases, the sensitivity of vegetation to extreme high temperatures increases, while sensitivity to extreme low temperatures decreases. Furthermore, the study also revealed differences in the responses of different vegetation types to extreme events under the same climatic conditions, highlighting the ecological basis of ecosystem resilience and adaptability. This research not only enhances our understanding of vegetation dynamics under the influence of extreme climate events but also provides scientific evidence for ecological management and climate adaptation in the Mongolian Plateau region.

Ecological Security Pattern Construction in Typical Oasis Area Based on Ant Colony Optimization: A Case Study in Yili River Valley, China

Establishing Ecological Security Pattern (ESP) is crucial for the harmonious development of society and the environment. Currently, the principal challenges in ecological planning include large contiguous ecological source areas and the accurate determination of ecological corridor widths. This study utilized the InVEST-MSPA-Conefor model, circuit theory, MATLAB, and the ArcGIS platform to analyze the Yili River Valley’s ESP, assess habitat quality, and identify habitat patch types. Results indicate that: (1) Habitat quality is higher in the southern and eastern parts of the river valley. The core area, vital for ecological connectivity, constituted 50.69 % of the study area. (2) Increased ecological resistance was predominantly observed in valley hills and near major transportation routes. (3) Seventy ecological corridors were identified, covering 3671.68 km2 of major and 6968.31 km2 of potential corridors, thus expanding the analysis from “source-line-point” to “source-line-point-plane” and strengthening ecological protection and management strategies. (4) The study proposes an optimization and management strategy of “Three Belts, Two Axes, and One Cluster” grounded in ESP results and local policies. The study advances the understanding of the Yili River Valley’s ecosystem structure, provides strategies for biodiversity conservation and ecological service optimization, and emphasizes the value of integrated, multi-dimensional modeling in ecological planning.

Extreme summer drought increased soil detachment capacity of biocrusts in subtropical China

Biological soil crusts (Biocrusts) are considered to have significant effects on soil detachment processes. Increasing extreme droughts are expected to affect the structure and functioning of biocrust ecosystems. However, understanding how biocrust ecosystems will respond to drought requires further investigation in the subtropical region. This study conducted continuously monitoring of understory biocrusts in subtropical China from May to November 2022, analyzed the monthly variation of near-surface characteristics of biocrusts and performed scouring experiments with six flow shear stresses (7.61–21.08 Pa) to assess the monthly variation of soil detachment capacity (Dc) of biocrusts. Finally, we elucidated the complex effects of summer drought (August-September) on Dc of biocrusts. Results showed that summer drought led to significant reductions in biocrust coverage (BC) and biocrust thickness (BT) (P<0.05), as well as notable declines in soil stability (including soil cohesion and Mean weight diameter) and soil nutrient content (including soil organic matter, total Nitrogen, total Phosphorus) (P<0.05), except for a non-significant increase in bulk density (P>0.05). Furthermore, Dc of biocrusts significantly increased by 172.2 % during the summer drought compared to the previous months (P<0.05). These changes of biocrusts are mainly affected by moisture stress more than heat stress. Partial least squares path modeling (PLS-PM) revealed that reduced rain and lower soil moisture increased Dc mainly by diminishing the BC and BT, followed by reducing soil cohesion and soil aggregate stability. The results provide empirical evidence for the cumulatively detrimental effects of future climate on biocrusts and contribute to more comprehensive understanding of biocrusts multifunctionality.

FEISTY Fortran library and R package to integrate fish and fisheries with biogeochemical models

Abstract The FishErIes Size and functional TYpe model (FEISTY) is a mechanistic ecosystem model that fully integrates ecosystem structure across trophic levels through functional types. We present an R package that enables users to run simulations ranging from a 0D chemostat to full global scales. The library is written in Fortran90 with an R interface and provides a web application for visual exploration. We present and compare results from four core configurations across a range of depths, productivity and fishing levels, and we assess the convergence of solutions as the number of size classes is increased. The model has historically been coupled to biogeochemical models of mesozooplankton and detritus production, but it can also be applied in a stand‐alone version. We demonstrate the library to set up and simulate fish communities under varying productivity of mesozooplankton and benthos, and top‐down forcing from fishing. We outline three strategies for coupling FEISTY with biogeochemical model output and discuss future directions and open issues.

Spatial Distribution of Calanoida in Freshwater Ecosystems and Their Application as a Food Web Assessment Index

Calanoida is a representative oligo-mesotrophic indicator species, frequently used as an index for assessing lake ecosystems’ health. Additionally, they function as trophic intermediates in the food web, connecting primary producers and higher consumers within lake ecosystems’ food chains. However, research cases that present the implications of habitat environment assessments, such as ecosystem structure and water quality, represented by these taxa remain insufficient. In this study, we conducted research across 49 lakes in South Korea, analyzing the occurrence characteristics of Calanoida and examining the correlations between Calanoida abundance and water quality parameters and the morphological-based functional groups of phytoplankton. Calanoida were more frequently observed in lakes characterized by greater size, increased depth, and reduced levels of anthropogenic land use. Furthermore, Calanoida occurrence was more probable in environments characterized by lower electrical conductivity and suspended solids concentrations. Their presence was also associated with conditions where Large mucilaginous phytoplankton (MBFG7), which includes cyanobacteria, and Large filamentous phytoplankton (MBFG3) were prevalent. An analysis of the environmental factors influencing the increase in Calanoida abundance revealed an inverse relationship between their abundance and water quality factors, including nutrient levels. This trend was observed consistently across all genera. Additionally, Calanoida were observed to maintain a high abundance in environments where the presence of the Large mucilaginous phytoplankton group (MBFG7) was relatively high. In contrast, Cyclopoida exhibited varying occurrence characteristics by genus in response to different water quality factors. Based on these results, we suggest that Calanoida, commonly used as an indicator of mesotrophic conditions, can also serve as a valuable indicator for evaluating the functionality of the food web. While Calanoida struggle to inhabit environments characterized by degraded water quality, they demonstrate the ability to adapt and persist in environments containing large, mucilaginous, or filamentous phytoplankton species that are typically challenging for other zooplankton to graze.

Effects of Biological Nitrogen Fixation and Nitrogen Deposition on Soil Microbial Communities in Karst Grassland Ecosystems

Diverse exogenous nitrogen (N) sources have a considerable impact on microbial community structure in terrestrial ecosystems. Legume plants and N deposition can relieve N limitations and increase net primary productivity. However, the differences in their effects on soil microbial communities remain unclear. Here, the responses of the soil microbial community to a legume-planting system and simulated N deposition were examined in karst grasslands in Southwest China over five years by analyzing soil microbial phospholipid fatty acids (PLFAs). The experiment included three treatments—legume plant introduction (NL, Indigofera atropurpurea), N deposition (ND, NH4NO3:10 g N m−2 yr−1), and a control with no treatment. The effects of NL and ND on soil microbial community composition differed significantly. ND significantly reduced the biomass of bacteria, actinobacteria, and arbuscular mycorrhizal fungi. NL insignificantly increased the biomass of all microbial groups. However, the total amounts of PLFAs and fungal biomass were significantly higher in NL than in ND. The effect of legume plant introduction on soil microbial community composition was more powerful than that of ND. Overall, the introduction of legume plants is beneficial in terms of increasing the biomass of the soil microbial community and stabilizing the soil microbial community structure in karst grassland ecosystems.

A Latin American network of microbial observatories for monitoring aquatic ecosystems

Freshwater environments and coastal marine areas provide key ecosystem services to society and serve as habitats for biodiversity. However, they face major challenges from human activities and climate factors, leading to global degradation. The effect of these agents depends on geographic location and climate, among other factors. To comprehensively understand the effect of these factors, continuous, standardized and long-term information is crucial. In particular, the aquatic microbiome plays a fundamental role in the cycling of matter and has been shown to act as a robust indicator of ecological status. Long-term monitoring of microbial assemblages can provide valuable insights into the characteristics and the changes water bodies undergo, delivering early warnings of critical impacts. Thus, the Latin American Aquatic Microbial Observatory Network (AMOLat) was set up during the inaugural meeting of the Latin American Collaborative Network on Microbial Aquatic Ecology (μSudAqua) in 2017. Observatory sites were carefully chosen, considering their accessibility and local relevance to each research group, ensuring the ongoing consistency of sampling efforts. This work aims to provide a historical overview of the network’s formation, highlighting key debates and definitions that took place during 2017-2023. Furthermore, it includes an initial characterization of the observatory sites and explores the possibilities that they offer to understand the structure and function of aquatic ecosystems in Latin America. The network presently encompasses 13 observatories, spanning a broad latitudinal range, numerous ecoregions and diverse aquatic ecosystems, displaying different environmental and anthropic impacts. Participating groups enhanced interactions, created a Protocol Book and showcased initial results through various communication efforts. Ultimately, establishing a regional network of aquatic observatories becomes mandatory for providing essential reference points to assess the response of microorganisms to global change in both the short and long term within Latin America.

Ecosystem service indicators on military-managed drylands in the Western United States.

Lands devoted to military use are globally important for the production of ecosystem services and for the conservation of biodiversity. The United States has one of the largest military land estates in the world, and most of these areas occur in water-limited landscapes. Despite many of these areas receiving intense or sustained disturbance from military training activities, the structure and function of ecosystems contained within their boundaries continue to provide critical benefits to people across spatial scales. The land owned and managed by the Department of Defense is subject to regulation across local, state, and federal governing bodies, constraining and shaping both how land management is conducted and how ecosystem services are prioritized. Here, we explored the supply of ecosystem services from military lands in dryland areas of the United States using key indicators of ecosystem services: biodiversity estimates derived from range maps, ecosystem productivity estimates from satellite observations, and spatially explicit, hierarchical ecosystem classifications. Additionally, we utilized content analysis of the environmental management plans of these areas to describe the unique set of demands and regulatory constraints on these areas. We found that the US military land estate in drylands contains many types of ecosystems and provides a large and diverse supply of ecosystem services, comparable to the sum of services from public lands in these areas. Additionally, the degree to which the ecosystem services concept is captured in environmental management plans is strongly shaped by the language of the governing legislation that mandated the use of environmental management plans in these areas, although these plans do not explicitly address land management using the concept of ecosystem services. Collectively, our findings suggest that military use and management of land represents an important source of ecosystem services, that military land use can be considered a cultural ecosystem service unto itself, and that top-down regulation can affect how these services are identified and valued. Our work highlights the need for the research and conservation communities to quantify ecosystem services from individual military installations so that both services and biodiversity can be safeguarded in an era of military conflict across the globe.

Nutrient enrichment can increase the thermal performance of Galápagos seaweeds

Thermal sensitivity in ectothermic organisms is often contingent upon environmental factors. Nutrient availability in particular is believed to influence the physiological responses of primary producers to global warming and is thus relevant to consider when forecasting the structure and functioning of future marine ecosystems. This study measured the effect of nutrient enrichment on the thermal sensitivity of 4 genera of Galápagos seaweeds (Ulva, Caulerpa, Padina, and Ochtodes), estimated as the thermal optimum (Topt), performance maximum (Pmax), activation energy, and deactivation energy. These parameters were quantified by modeling thermal performance curves for net photosynthesis under ambient and nutrient-enriched conditions. Our findings revealed variation in Topt among genera, ranging from 27.6° to 36.0°C. Nutrient additions enhanced Topt by ~2°C for 2 (Padina and Caulerpa) of the 4 taxa and also significantly increased Pmax in Padina, suggesting the ability for warming-induced ocean stratification and associated effects (i.e. decreasing nutrient availability) to reduce the capacities of these populations to maintain and support new growth. No significant differences in Topt or Pmax were observed for either Ulva or Ochtodes with enrichment. Ambient net photosynthesis and respiration rates were also compared across genera; Pmax rates for net photosynthesis were consistently higher than those for respiration (i.e. until just beyond Topt); however, photosynthetic Topt values were lower. Thus, this study suggests that further warming could reduce overall net primary productivity, with potentially far-reaching implications for marine food webs.