Development Of Ecosystem Models Research Articles

Концептуальные подходы к изучению партнерства в зарубежной теории экосистем

Ecosystem theory offers new perspectives for understanding the behavior of economic agents, their relationships, and the conditions for coordinating interests. This study focuses on the partnerships that emerge between participants in ecosystems. The article aims to review key approaches and synthesize theoretical contributions by Russian and international researchers that advance ecosystem theory. The study addresses several objectives: identifying the prerequisites for the emergence of ecosystem theory and its distinctions from related concepts like entrepreneurial communities; analyzing the structure and main components of ecosystems; exa­mining the motives for partnerships and cooperation; and explaining the dynamics of co-opetition (simultaneous cooperation and competition) and informal relationships within ecosystems. Methodologically, the study relies on content analysis of research literature, synthesis of economic theories, grouping of concepts, and development of ecosystem models. The findings highlight unique properties of ecosystems, such as heterogeneity, complementarity, affiliation, modularity, emergence, coevolution, and adaptability. Key rules governing complementarity are outlined, and partnership motives are categorized into four approaches: resource, technologi­cal, transactional, and market. The study further elucidates the nature of co-opetition, its characteristics, and the patterns governing formal and informal contracts between ecosystem participants. This study contributes to ecosystem theory by formulating new theoretical approaches and integrating economic concepts to enhance understanding. The findings lay the groundwork for a comprehensive theory, guiding future research and validating the proposed hypotheses. Future directions include typologizing partnerships, exploring conflict resolution in co-opetition, evaluating its effects on ecosystem dynamics, and devising mechanisms to coordinate participants’ interests.

Action science in practice: Co‐production of a decision support tool visualizing effects of nutrient and hypoxia reduction goals on fisheries species

AbstractObjectiveThe Gulf of Mexico hosts some of the most productive fisheries in the United States, whereas the same region is known to experience environmental stressors, such as summer hypoxia. Ecosystem models have been developed for the Gulf of Mexico to determine how hypoxia affects living marine resources, but these models and their output are not always easy to access or interpret by managers, thereby decreasing their implementation in a management setting. To help alleviate the gap between ecosystem model development and management utility, the current study focuses on co‐produced, user‐friendly tools that describe the effects of nutrient and hypoxia reductions on marine living resources.MethodsTwo decisions were made prior to the ecosystem model development to facilitate the transfer of model output: (1) to engage and consult fisheries and restoration managers throughout ecosystem model development to ensure that the output would provide relevant information; and (2) to provide an accessible visualization tool for making ecosystem model output readily available to support the needs of decision makers.ResultResults from an advisory panel survey instrument and advisory panel meetings guided ecosystem model development and launched the development of a decision support tool. The iterative process of building a decision support tool incorporating feedback from survey instrument respondents resulted in an ESRI ArcGIS Dashboard that allows end‐users to identify the effects of hypoxia and respondent‐specified nutrient and hypoxia reduction goals on the biomass and distribution of fisheries species.ConclusionThe intent is to aid managers who are actively working to address hypoxia in the Gulf of Mexico with easy‐to‐access information on the effects of planned actions and to encourage future modelers to apply action science principles to best address the needs of decision makers.

Trophic guilds of marine predators in the California Current Large Marine Ecosystem

Quantifying trophic relationships of marine species is fundamental to the construction and performance of ecosystem models, development of effective ecosystem-based fisheries management strategies, and support of trait-based approaches to ecological risk assessment. Accounting for food web dynamics in taxonomically diverse ecosystems, such as the California Current Large Marine Ecosystem (CCLME), is especially challenging because of the sheer number of trophic linkages and their inherent variability. Consequently, analyses that can inform the most appropriate means of aggregating species or other taxonomic groups into assemblages or guilds are critical to reducing system complexity for modeling and management, particularly when data are limited. To provide a methodological approach that is globally applicable in such cases, we define trophic guilds within biogeographic regions of the CCLME, compare results among these regions, and discuss ecological and management implications. Within each biogeographic region, predator guilds were clearly demarcated by foraging habitat (benthic, nearshore pelagic, offshore pelagic), scale of foraging movements, and trophic position. Furthermore, trophic guilds were distinctive for each region, with species composition and the noted ecological characteristics largely driving guild structure. Predator species that are reliant on continental slope and offshore foraging habitat, such as adult Pacific Hake, have diets that are representative of these areas and are similar throughout the CCLME. Generally, larger, more mobile predators that typically feed in deeper offshore waters, including swordfish, sea lions, and sharks clustered together in multiple bioregions along the coast; all reliant primarily on fishes and squids. Throughout bioregions, groundfishes preyed on benthic invertebrates (e.g., decapods, amphipods, polychaetes), while shelf-oriented pelagic predators, including smaller salmon, preyed on pelagic invertebrates (e.g., euphausiids, copepods, gelatinous zooplankton). A large number of forage taxa that are well represented in this study have dynamics largely dependent on oceanographic conditions at a regional scale (e.g., decapods), basin scale (e.g., copepods), or a combination of both (e.g., euphausiids, Northern Anchovy). Such distinctions indicate that spatial and temporal scales of coherence of predators and prey also must be considered in development of ecosystem models and evaluation of management strategies. Our study quantifies the spatial coherence of predator guilds integrated over decades within and across bioregions of the CCLME, providing an improved understanding of regional ecosystem functioning. The analytical approach we developed may be easily extended to address similar ecological and ecosystem based fisheries management priorities in other marine regions.

Responses of benthic calcifying algae to ocean acidification differ between laboratory and field settings

Abstract Accurately predicting the effects of ocean and coastal acidification on marine ecosystems requires understanding how responses scale from laboratory experiments to the natural world. Using benthic calcifying macroalgae as a model system, we performed a semi-quantitative synthesis to compare directional responses between laboratory experiments and field studies. Variability in ecological, spatial, and temporal scales across studies, and the disparity in the number of responses documented in laboratory and field settings, make direct comparisons difficult. Despite these differences, some responses, including community-level measurements, were consistent across laboratory and field studies. However, there were also mismatches in the directionality of many responses with more negative acidification impacts reported in laboratory experiments. Recommendations to improve our ability to scale responses include: (i) developing novel approaches to allow measurements of the same responses in laboratory and field settings, and (ii) researching understudied calcifying benthic macroalgal species and responses. Incorporating these guidelines into research programs will yield data more suitable for robust meta-analyses and will facilitate the development of ecosystem models that incorporate proper scaling of organismal responses to in situ acidification. This, in turn, will allow for more accurate predictions of future changes in ecosystem health and function in a rapidly changing natural climate.

Rhizosphere effects of woody plants on soil biogeochemical processes: A meta-analysis

Rhizosphere effects control soil biogeochemical cycling. However, quantitative assessment of rhizosphere effects on belowground processes such as carbon and nitrogen cycling remains rare, especially for woody species in field experiments. Here, we conducted a meta-analysis to synthesize the rhizosphere effects of woody plants (185 species from 128 sites) on belowground processes (20 variables), including soil carbon and nutrient pools, microbial biomass, enzyme activities, and carbon and net nitrogen mineralization rates. We also explored the effects of plant mycorrhizal types (arbuscular mycorrhizal, AM vs. ectomycorrhizal, ECM), leaf traits (evergreen vs. deciduous, broadleaf vs. coniferous), bulk soil properties and climatic factors on these rhizosphere effects. Our results indicated that the rhizosphere effects were positive on all variables except soil pH and phenol oxidase activity. Most rhizosphere effects did not vary significantly between mycorrhizal types, but the effect on soil nitrate-N was notably lower under ECM-associated species than under AM-associated species. Rhizosphere effects increased carbon and net nitrogen mineralization rates by 38% and 40% on average, and the variation was mainly affected by bulk soil properties (e.g., pH, soil organic carbon and available nitrogen concentrations) rather than plant functional types and climatic factors. Collectively, these results provide quantitative evidence that rhizosphere effects influence belowground carbon and nutrient cycling in forest ecosystems, which are helpful for the development of ecosystem models that explicitly consider plant-soil interactions in the rhizosphere.

The Path to an Ecosystem Approach for Forage Fish Management: A Case Study of Atlantic Menhaden

Atlantic menhaden (Brevoortia tyrannus) support the largest fishery by volume on the United States East Coast, while also playing an important role as a forage species. Managers’ and stakeholders’ increasing concerns about the impact of Atlantic menhaden harvest on ecosystem processes led to an evolution in the assessment and management of this species from a purely single-species approach to an ecosystem approach. The first coastwide stock assessment of Atlantic menhaden for management used a single-species virtual population analysis (VPA). Subsequent assessments used a forward projecting statistical catch-at-age framework that incorporated estimates of predation mortality from a multispecies VPA while analytical efforts continued toward the development of ecosystem models and explicit ecological reference points (ERPs) for Atlantic menhaden. As an interim step while ecosystem models were being developed, a series of ad hoc measures to preserve Atlantic menhaden biomass for predators were used by managers. In August 2020, the Atlantic States Marine Fisheries Commission formally adopted an ecological modeling framework as a tool to set reference points and harvest limits for the Atlantic menhaden that considers their role as a forage fish. This is the first example of a quantitative ecosystem approach to setting reference points on the United States Atlantic Coast and it represents a significant advance for forage fish management. This case study reviews the history of Atlantic menhaden stock assessments and management, outlines the progress on the current implementation of ERPs for this species, and highlights future research and management needs to improve and expand ecosystem-based fisheries management.

Revealing environmental forcing in the different trophic guilds of fish communities off the Western Mediterranean Sea

The dietary preferences of 61 Western Mediterranean species of fish belonging to different trophic levels were studied. Specimens were collected during the annual bottom trawl survey MEDITS for the period 2011–2018, with a total of 16,588 stomach contents analyzed, providing a highly valuable raw dataset for advanced studies in trophic ecology. The software EstimateS 9.1 was used, for the first time in a study of Mediterranean fish species, to estimate cumulative prey curves in order to determine the adequacy of the sample size for each species in representing the species diet. The main findings revealed the existence of nine well-identified feeding strategies, or trophic guilds, based on food preferences. Indicators, namely the Shannon diversity index, biomass estimated from standard surveys, mean trophic level and fish community composition, were used to categorize the structure of the fish community in Western Mediterranean marine food webs. In addition, the effects of latitude, depth and habitat type on fish community structure were investigated. Results show all these environmental factors investigated drove fish composition structure. Regarding the three variables investigated, depth had the greatest impact on the fish community structure, particularly affecting diversity and fish community composition. Latitudinal gradient only seemed to affect fish community composition, showing consistency along a latitudinal north-south axis. Habitat type was found to be significant in fish community structure. Mean trophic level was the only indicator that was not affected significantly by environmental variables. The present study shows the relevance of environmental forcing in fish community structure. These findings highlight the need of ecosystem studies, since information about the trophic networks in the study area is still scarce, jeopardizing the development of ecosystem models. The present work aims to fill this gap for the effective implementation of an ecosystem approach to fisheries management in the Western Mediterranean Sea.

Entrepreneurship Ecosystem and Development of Entrepreneurship in Pakistan

The study has been taken in order to explore the concept of entrepreneurship ecosystem and how the development of ecosystem model has an impact on the development of entrepreneurship in Pakistan. Hence, the top-down and bottom up approach both were used simultaneously in order to comprehend the entrepreneurship ecosystem phenomenon under investigation. The entrepreneurship ecosystem has been analyzed through SMEDA SME policies, cultural tendency and private educational institutions’ capacities in Pakistan in the quantitative part of the study. This study is however, guided by Isenberg (2011) and Mason and Brown (2014) through their scholarly work on entrepreneurship and entrepreneurship ecosystem. The mixed methods research strategy and parallel convergent design were used to understand and explore the phenomenon and hence quantitative and qualitative data were collected simultaneously. Although, the quantitative data were collected through convenience sampling from six universities, interviews were conducted at the same time from academic professionals, incubation center representatives and entrepreneurs as well. The quantitative data were then analyzed through SPSS and qualitative data through trial version of NVivo 12. The quantitative results show the significant relationship between SMEDA SME policies and development of entrepreneurship; however, the strength of relationship was considered to be weak. Similarly, the significant relationship was also found between cultural tendency and development of entrepreneurship in Pakistan; however strength of relationship was also weak. Moreover, the significant relationship was found between private educational institutions’ capacities and development of entrepreneurship but, the strength of relationship was weak in nature. However, while testing the final hypothesis, the relationship between cumulative SMEDA policies, cultural tendency, private educational intuitions’ capacities and entrepreneurship development in Pakistan was also found with moderate strength of association. While converging the data from quantitative and qualitative part, it was observed that, both data do converge at some point, because factors emerged in the qualitative data (family system, educational system, entrepreneurial attributes, and legal framework and incubation centers) and the results found in the quantitative data do find the relationship between with the entrepreneurship ecosystem and the development of entrepreneurship in Pakistan.

DNA-based diet analysis of mesopelagic fish from the southern Kerguelen Axis

Mesopelagic fish form an important link between zooplankton and higher trophic levels in Southern Ocean food webs, however their diets are poorly known. Most of the dietary information available comes from morphological analysis of stomach contents and to a lesser extent fatty acid and stable isotopes. DNA sequencing could substantially improve our knowledge of mesopelagic fish diets, but has not previously been applied. We used high-throughput DNA sequencing (HTS) of the 18S ribosomal DNA and mitochondrial cytochrome oxidase I (COI) to characterise stomach contents of four myctophid and one bathylagid species collected at the southern extension of the Kerguelen Plateau (southern Kerguelen Axis), one of the most productive regions in the Indian sector of the Southern Ocean. Diets of the four myctophid species were dominated by amphipods, euphausiids and copepods, whereas radiolarians and siphonophores contributed a much greater proportion of HTS reads for Bathylagus sp. Analysis of mitochondrial COI showed that all species preyed on Thysanoessa macrura, but Euphausia superba was only detected in the stomach contents of myctophids. Size-based shifts in diet were apparent, with larger individuals of both bathylagid and myctophid species more likely to consume euphausiids, but we found little evidence for regional differences in diet composition for each species over the survey area. The presence of DNA from coelenterates and other gelatinous prey in the stomach contents of all five species suggests the importance of these taxa in the diet of Southern Ocean mesopelagics has been underestimated to date. Our study demonstrates the use of DNA-based diet assessment to determine the role of mesopelagic fish and their trophic position in the Southern Ocean and inform the development of ecosystem models.

Integration of satellite remote sensing data in ecosystem modelling at local scales: Practices and trends

Abstract Spatiotemporal ecological modelling of terrestrial ecosystems relies on climatological and biophysical Earth observations. Due to their increasing availability, global coverage, frequent acquisition and high spatial resolution, satellite remote sensing (SRS) products are frequently integrated to in situ data in the development of ecosystem models (EMs) quantifying the interaction among the vegetation component and the hydrological, energy and nutrient cycles. This review highlights the main advances achieved in the last decade in combining SRS data with EMs, with particular attention to the challenges modellers face for applications at local scales (e.g. small watersheds). We critically review the literature on progress made towards integration of SRS data into terrestrial EMs: (1) as input to define model drivers; (2) as reference to validate model results; and (3) as a tool to sequentially update the state variables, and to quantify and reduce model uncertainty. The number of applications provided in the literature shows that EMs may profit greatly from the inclusion of spatial parameters and forcings provided by vegetation and climatic‐related SRS products. Limiting factors for the application of such models to local scales are: (1) mismatch between the resolution of SRS products and model grid; (2) unavailability of specific products in free and public online repositories; (3) temporal gaps in SRS data; and (4) quantification of model and measurement uncertainties. This review provides examples of possible solutions adopted in recent literature, with particular reference to the spatiotemporal scales of analysis and data accuracy. We propose that analysis methods such as stochastic downscaling techniques and multi‐sensor/multi‐platform fusion approaches are necessary to improve the quality of SRS data for local applications. Moreover, we suggest coupling models with data assimilation techniques to improve their forecast abilities. This review encourages the use of SRS data in EMs for local applications, and underlines the necessity for a closer collaboration among EM developers and remote sensing scientists. With more upcoming satellite missions, especially the Sentinel platforms, concerted efforts to further integrate SRS into modelling are in great demand and these types of applications will certainly proliferate.

Ecological Modeling of the Supraglacial Ecosystem: A Process-based Perspective

Glacier and ice sheet surfaces are important microbe-dominated ecosystems that are changing rapidly due to climate change, with potentially significant impacts. A theoretical framework of the supraglacial (glacier surface) ecosystem is needed to enable its mathematical modelling, a necessary tool for understanding, quantifying and predicting present day and future ecosystem dynamics. Here we review key biological processes occurring on glacier and ice sheet surfaces and present three frameworks for constructing process-based models of the surface ecosystem, using the largest supraglacial ecosystem on Earth – the Greenland ice sheet surface – as an important example. The models are based on organic carbon transformations, but vary in numerical complexity and in the level of detail of biological processes. This perspective is intended to guide future supraglacial ecosystem model development, field data collection for parameterisation and validation purposes, and encourage inter-disciplinary collaboration between modellers and experimentalists.

The importance of time of day in structuring demersal ichthyofaunal assemblages on the West Florida Shelf

Although turnover of reef-fish assemblages based on time of day has been generally well documented, much less is known regarding diel dynamics of demersal fish communities along the continental shelf of the US Gulf of Mexico. We analyzed trawl data collected as part of the Gulf of Mexico Southeast Area Monitoring and Assessment Program (SEAMAP) to document diel changes in fish abundance and assess the relative importance of space and time of day in structuring demersal fish assemblages. Trawling operations were conducted day and night in neritic waters from southern Florida to eastern Alabama (West Florida Shelf). Ichthyofaunal assemblages differed by region and depth, but also by time of day (day, night, crepuscular) within region and depth categories. Both fish abundance and diversity were generally highest at night. Some day/night differences in abundance for particular species can be attributed to specific behaviors, such as nighttime foraging in open areas coupled with cryptic habits (e.g., burrowing, shelter-seeking). Prominent examples of such behavior-associated abundance patterns include cusk-eels (Ophidiidae), which are burrowers, and grunts (Haemulidae), which are closely associated with structural habitats during daytime. We document these strong diel trends in the SEAMAP trawl data and interpret them based on current understanding of the behavior of fish species and families and in relation to the development of ecosystem models for management purposes.

Developing a polycyclic aromatic hydrocarbon exposure dose-response model for fish health and growth

One of the more important steps in understanding the ecosystem-level effects of anthropogenic disturbances on resident species is developing an accurate representation of the lethal and sub-lethal effects of these stressors. We develop methods for describing the impacts of oil on growth and mortality rates in fishes. We conducted a literature search to determine potential relationships between direct and indirect effects of exposure to oil, based on the frequency of lesions and body growth reduction. Data examining these effects with different exposure mediums were assessed and then input into four potential response models (a linear, step-wise, hockey-stick, and exponential model). We assessed the models using the Akaike Information Criterion. The most parsimonious and best fit model was the hockey-stick. This analysis will aid in identifying where future research on the impact of oil on fish should focus and also aid the development of ecosystem models on impacts of oil spills.

Progression of a Gulf of Mexico food web supporting Atlantis ecosystem model development

This article develops a marine food web matrix for the Gulf of Mexico (GOM) based on local stomach sampling and online diet information. Working at the level of functional groups, we fit diet information to a statistical model based on the Dirichlet distribution. This allows us to quantify likely contributions of prey to predators’ diets. Error ranges on these values reflect diet variability and data quality, and help in identifying functional groups that would benefit from additional sampling. We perform hierarchical cluster analysis to determine functional groups that have similar prey requirements, then produce a food web diagram representing the interactions between predators and prey. A meta-analysis using principle coordinate analysis allows us to compare this study’s diet matrix with ten other published GOM food webs and determine where variation in food web structure exists. We also compare our new food web to the diet matrix used by the Ainsworth et al. (2015) Atlantis ecosystem model, a strategic tool developed to assess ecosystem dynamics in the GOM. A hindcast from 1980 to 2010 using Atlantis shows an improved fit to observational data and reduced error in biomass projections using the revised diet information.

Drivers of summer oxygen depletion in the central North Sea

Abstract. In stratified shelf seas, oxygen depletion beneath the thermocline is a result of a greater rate of biological oxygen demand than the rate of supply of oxygenated water. Suitably equipped gliders are uniquely placed to observe both the supply through the thermocline and the consumption of oxygen in the bottom layers. A Seaglider was deployed in the shallow (≈ 100 m) stratified North Sea in a region of known low oxygen during August 2011 to investigate the processes regulating supply and consumption of dissolved oxygen below the pycnocline. The first deployment of such a device in this area, it provided extremely high-resolution observations, 316 profiles (every 16 min, vertical resolution of 1 m) of conductivity, temperature, and depth (CTD), dissolved oxygen concentrations, backscatter, and fluorescence during a 3-day deployment.The high temporal resolution observations revealed occasional small-scale events (< 200 m or 6 h) that supply oxygenated water to the bottom layer at a rate of 2 ± 1 µmol dm−3 day−1. Benthic and pelagic oxygen sinks, quantified through glider observations and past studies, indicate more gradual background consumption rates of 2.5 ± 1 µmol dm−3 day−1. This budget revealed that the balance of oxygen supply and demand is in agreement with previous studies of the North Sea. However, the glider data show a net oxygen consumption rate of 2.8 ± 0.3 µmol dm−3 day−1, indicating a localized or short-lived (< 200 m or 6 h) increase in oxygen consumption rates. This high rate of oxygen consumption is indicative of an unidentified oxygen sink. We propose that this elevated oxygen consumption is linked to localized depocentres and rapid remineralization of resuspended organic matter.The glider proved to be an excellent tool for monitoring shelf sea processes despite challenges to glider flight posed by high tidal velocities, shallow bathymetry, and very strong density gradients. The direct observation of these processes allows more up to date rates to be used in the development of ecosystem models.

Bioenergetics, Trophic Ecology, and Niche Separation of Tunas.

Tunas are highly specialized predators that have evolved numerous adaptations for a lifestyle that requires large amounts of energy consumption. Here we review our understanding of the bioenergetics and feeding dynamics of tunas on a global scale, with an emphasis on yellowfin, bigeye, skipjack, albacore, and Atlantic bluefin tunas. Food consumption balances bioenergetics expenditures for respiration, growth (including gonad production), specific dynamic action, egestion, and excretion. Tunas feed across the micronekton and some large zooplankton. Some tunas appear to time their life history to take advantage of ephemeral aggregations of crustacean, fish, and molluscan prey. Ontogenetic and spatial diet differences are substantial, and significant interdecadal changes in prey composition have been observed. Diet shifts from larger to smaller prey taxa highlight ecosystem-wide changes in prey availability and diversity and provide implications for changing bioenergetics requirements into the future. Where tunas overlap, we show evidence of niche separation between them; resources are divided largely by differences in diet percentages and size ranges of prey taxa. The lack of long-term data limits the ability to predict impacts of climate change on tuna feeding behaviour. We note the need for systematic collection of feeding data as part of routine monitoring of these species, and we highlight the advantages of using biochemical techniques for broad-scale analyses of trophic relations. We support the continued development of ecosystem models, which all too often lack the regional-specific trophic data needed to adequately investigate climate and fishing impacts.

Nitrogen deposition and its effect on carbon storage in Chinese forests during 1981–2010

Abstract Human activities have resulted in dramatically increased nitrogen (N) deposition worldwide, which is closely linked to the carbon (C)-cycle processes and is considered to facilitate terrestrial C sinks. In this study, we firstly estimated the spatial and temporal variations of N deposition during 1981–2010 based on a new algorithm; then we used a newly improved process-based ecosystem model, CEVSA2, to examine the effects of N deposition on C storage in Chinese forests. The results show that the rate of N deposition increased by 0.058 g N m −2 yr −1 between 1981 and 2010. The N deposition rate in 2010 was 2.32 g N m −2 yr −1 , representing a large spatial variation from 0 to 0.25 g N m −2 yr −1 on the northwestern Qinghai–Tibet Plateau to over 4.5 g N m −2 yr −1 in the southeastern China. The model simulations suggest that N deposition induced a 4.78% increase in the total C storage in Chinese forests, most of which accumulated in vegetation. C storage increased together with the increase in N deposition, in both space and time. However, N use efficiency was highest when N deposition was 0.4–1.0 g N m −2 yr −1 . We suggest conducting more manipulation experiments and observations in different vegetation types, which will be greatly helpful to incorporate additional processes and mechanisms into the ecosystem modeling. Further development of ecosystem models and identification of C–N interactions will be important for determining the effects of N input on C cycles on both regional and global scales.

Resolution of Respect: Paul Risser, 1939–2014

Resolution of Respect: Paul Risser, 1939–2014

Challenges in integrative approaches to modelling the marine ecosystems of the North Atlantic: Physics to fish and coasts to ocean

It has long been recognised that there are strong interactions and feedbacks between climate, upper ocean biogeochemistry and marine food webs, and also that food web structure and phytoplankton community distribution are important determinants of variability in carbon production and export from the euphotic zone. Numerical models provide a vital tool to explore these interactions, given their capability to investigate multiple connected components of the system and the sensitivity to multiple drivers, including potential future conditions. A major driver for ecosystem model development is the demand for quantitative tools to support ecosystem-based management initiatives. The purpose of this paper is to review approaches to the modelling of marine ecosystems with a focus on the North Atlantic Ocean and its adjacent shelf seas, and to highlight the challenges they face and suggest ways forward. We consider the state of the art in simulating oceans and shelf sea physics, planktonic and higher trophic level ecosystems, and look towards building an integrative approach with these existing tools. We note how the different approaches have evolved historically and that many of the previous obstacles to harmonisation may no longer be present. We illustrate this with examples from the on-going and planned modelling effort in the Integrative Modelling Work Package of the EURO-BASIN programme.

Do we need to understand microbial communities to predict ecosystem function? A comparison of statistical models of nitrogen cycling processes

Despite the central role of microorganisms in biogeochemistry, process models rarely explicitly account for variation in communities. Here, we use statistical models to address a fundamental question in ecosystem ecology: do we need to better understand microbial communities to accurately predict ecosystem function? Nitrogen (N) cycle process rates and associated gene abundances were measured in tropical rainforest soil samples collected in May (early wet season) and October (late wet season). We used stepwise linear regressions to examine the explanatory power of edaphic factors and functional gene relative abundances alone and in combination for N-cycle processes, using both our full dataset and seasonal subsets of the data. In our full dataset, no models using gene abundance data explained more variation in process rates than models based on edaphic factors alone, and models that contained both edaphic factors and community data did not explain significantly more variation in process rates than edaphic factor models. However, when seasonal datasets were examined separately, microbial predictors enhanced the explanatory power of edaphic predictors on dissimilatory nitrate reduction to ammonium and N2O efflux rates during October. Because there was little variation in the explanatory power of microbial predictors alone between seasonal datasets, our results suggest that environmental factors we did not measure may be more important in structuring communities and regulating processes in October than in May. Thus, temporal dynamics are key to understanding the relationships between edaphic factors, microbial communities and ecosystem function in this system. The simple statistical method presented here can accommodate a variety of data types and should help prioritize what forms of data may be most useful in ecosystem model development.