Larval Dispersal and Marine Population Connectivity

Annual Review of Marine Science, Journal Year: 2008, Volume and Issue: 1(1), P. 443 - 466

Published: Sept. 23, 2008

Connectivity, or the exchange of individuals among marine populations, is a central topic in ecology. For most benthic species with complex life cycles, this occurs primarily during pelagic larval stage. The small size larvae coupled vast and fluid environment they occupy hamper our ability to quantify dispersal connectivity. Evidence from direct indirect approaches using geochemical genetic techniques suggests that populations range fully open closed. Understanding biophysical processes contribute observed patterns requires integrated interdisciplinary incorporate high-resolution modeling empirical data. Further, differential postsettlement survival may add complexity measurements degree which self recruit receive subsidy other has consequences for number fundamental ecological affect population regulation persistence. Finally, full understanding connectivity important applications management conservation.

Language: Английский

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Characterising performance of environmental models

Environmental Modelling & Software, Journal Year: 2012, Volume and Issue: 40, P. 1 - 20

Published: Nov. 6, 2012

Language: Английский

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The re-eutrophication of Lake Erie: Harmful algal blooms and hypoxia

Harmful Algae, Journal Year: 2016, Volume and Issue: 56, P. 44 - 66

Published: May 18, 2016

Language: Английский

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Skill assessment for coupled biological/physical models of marine systems

Journal of Marine Systems, Journal Year: 2008, Volume and Issue: 76(1-2), P. 4 - 15

Published: June 4, 2008

Language: Английский

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Temporal responses of coastal hypoxia to nutrient loading and physical controls

Biogeosciences, Journal Year: 2009, Volume and Issue: 6(12), P. 2985 - 3008

Published: Dec. 15, 2009

Abstract. The incidence and intensity of hypoxic waters in coastal aquatic ecosystems has been expanding recent decades coincident with eutrophication the zone. Worldwide, there is strong interest reducing size duration hypoxia waters, because causes negative effects for many organisms ecosystem processes. Although strategies to reduce by decreasing nutrient loading are predicated on assumption that this action would reverse eutrophication, analyses historical data from European North American systems suggest little evidence simple linear response trajectories. We review published parallel time-series rates inorganic nutrients labile organic matter analyze trajectories oxygen (O2) loading. also assess existing knowledge physical ecological factors regulating O2 marine facilitate analysis responses reductions (and/or matter) inputs. Of 24 identified where concurrent time series were available, half displayed relatively clear direct recoveries following remediation. explored detail 5 well-studied have exhibited complex, non-linear variations loading, including apparent "regime shifts". A summary these suggests conditions improved rapidly linearly remediation focused inputs sewage treatment plants, which primary drivers hypoxia. In larger more open diffuse loads important fueling depletion climatic influences pronounced, tended follow trends may include hysteresis time-lags. Improved understanding requires future studies use comparative approaches consider multiple factors. These should consider: (1) dominant temporal scales hypoxia, (2) relative contributions nutrients, (3) influence shifts oceanographic processes, (4) roles feedback interactions whereby O2-sensitive biogeochemistry, trophic interactions, habitat algal dynamics regulate levels.

Language: Английский

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Plankton functional type modelling: running before we can walk?

Journal of Plankton Research, Journal Year: 2005, Volume and Issue: 27(11), P. 1073 - 1081

Published: Oct. 6, 2005

Biogeochemical cycling in marine systems is intimately linked to the activity of specific plankton functional types (PFTs) such as diatoms, coccolithophores and nitrogen fixers, thereby providing a focus for contemporary modelling studies. Incorporating extra complexity beyond simple nutrient-phytoplankton-zooplankton-detritus (NPZD) models is, however, fraught with difficulties: poorly understood ecology; lack data; aggregating diversity within groups into meaningful state variables constants; sensitivity output parameterizations question their physical chemical environment. Although regional addressing seasonal succession have achieved some degree success, predicted distributions PFTs global biogeochemical thus far been less than convincing. While continued articulation detail ecosystem surely way forward, I argue that this can only be so due care attention formulations employed healthy dose scepticism regarding model outcomes. Future directions should emphasize building up gradually, objective assessment resulting parameterizations, variety approach use empirical alternatives fully dynamic representation models.

Language: Английский

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Process‐Guided Deep Learning Predictions of Lake Water Temperature

Water Resources Research, Journal Year: 2019, Volume and Issue: 55(11), P. 9173 - 9190

Published: Nov. 1, 2019

Abstract The rapid growth of data in water resources has created new opportunities to accelerate knowledge discovery with the use advanced deep learning tools. Hybrid models that integrate theory state‐of‐the art empirical techniques have potential improve predictions while remaining true physical laws. This paper evaluates Process‐Guided Deep Learning (PGDL) hybrid modeling framework a use‐case predicting depth‐specific lake temperatures. PGDL model three primary components: temporal awareness (long short‐term memory recurrence), theory‐based feedback (model penalties for violating conversation energy), and pretraining initialize network synthetic (water temperature from process‐based model). In situ temperatures were used train model, (DL) (PB) model. Model performance was evaluated various conditions, including when training sparse made outside range set. (as measured by root‐mean‐square error (RMSE)) superior DL PB two detailed study lakes, but only included greater variability than period. also performed well extended 68 median RMSE 1.65 °C during test period (DL: 1.78 °C, PB: 2.03 °C; small number lakes or more accurate). case‐study demonstrates integrating scientific into tools shows promise improving many important environmental variables.

Language: Английский

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Assessment of skill and portability in regional marine biogeochemical models: Role of multiple planktonic groups

Journal of Geophysical Research Atmospheres, Journal Year: 2007, Volume and Issue: 112(C8)

Published: Aug. 1, 2007

Application of biogeochemical models to the study marine ecosystems is pervasive, yet objective quantification these models' performance rare. Here, 12 lower trophic level varying complexity are objectively assessed in two distinct regions (equatorial Pacific and Arabian Sea). Each model was run within an identical one‐dimensional physical framework. A consistent variational adjoint implementation assimilating chlorophyll‐a, nitrate, export, primary productivity applied same metrics were used assess skill. Experiments performed which data assimilated from each site individually both sites simultaneously. cross‐validation experiment also conducted whereby one resulting optimal parameters generate a simulation for second site. When single pelagic regime considered, simplest fit as well those with multiple phytoplankton functional groups. However, groups produced misfits when required simulate regimes using parameter values. The experiments revealed that long only few key optimized, greater generally more portable. Furthermore, zooplankton compartments did not necessarily outperform compartments, even biomass assimilated. Finally, different similar least squares model‐data misfits, they often so via very element flow pathways, highlighting need comprehensive sets uniquely constrain pathways.

Language: Английский

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Challenges and opportunities for integrating lake ecosystem modelling approaches

Aquatic Ecology, Journal Year: 2010, Volume and Issue: 44(3), P. 633 - 667

Published: Aug. 26, 2010

A large number and wide variety of lake ecosystem models have been developed published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more largely following concept others ('reinventing wheel'). The other focusing on only one type model, while ignoring new diverse approaches that become available ('having tunnel vision'). In paper, we aim at improving awareness existing knowledge concurrent modelling, without covering all possible model tools avenues. First, present a broad modelling approaches. To illustrate these approaches, give brief descriptions rather arbitrarily selected sets specific models. deal with static (steady state regression models), complex dynamic (CAEDYM, CE-QUAL-W2, Delft 3D-ECO, LakeMab, LakeWeb, MyLake, PCLake, PROTECH, SALMO), structurally minimal also discuss group could be classified as individual based: super-individual (Piscator, Charisma), physiologically structured models, stage-structured trait-based briefly mention genetic algorithms, neural networks, Kalman filters fuzzy logic. Thereafter, zoom in, an in-depth example, multi-decadal development application PCLake related (PCLake Metamodel, Lake Shira Model, IPH-TRIM3D-PCLake). discussion, argue historical each approach understandable given its 'leading principle', there are many opportunities combining take point view single 'right' does not exist should strived for. Instead, multiple applied concurrently problem, can help develop integrative functioning ecosystems. end set recommendations may

Language: Английский

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Seasonal and inter-annual variability of plankton chlorophyll and primary production in the Mediterranean Sea: a modelling approach

Biogeosciences, Journal Year: 2012, Volume and Issue: 9(1), P. 217 - 233

Published: Jan. 11, 2012

Abstract. This study presents a model of chlorophyll and primary production in the pelagic Mediterranean Sea. A 3-D-biogeochemical (OPATM-BFM) was adopted to explore specific system characteristics quantify dynamics key biogeochemical variables over 6 yr period, from 1999 2004. We show that, on basin scale, Sea is characterised by high degree spatial temporal variability terms concentrations. On important horizontal vertical gradients have been observed. According simulations developed correctly simulated climatological features deep maxima west-east gradients, as well seasonal main offshore regions that were studied. The integrated net highlights north-south differ surface illustrates importance resolving variations calculate basin-wide budgets their variability. model, western Mediterranean, particular Alboran Sea, can be considered mesotrophic, whereas eastern oligotrophic. During summer stratified notable differences between corresponding vertically rates identified, suggesting care must taken when inferring productivity such systems satellite observations alone. Finally, designed role external fluxes light penetration performed. subsequent results effects atmospheric terrestrial nutrient loads total account for less than 5 % its annual value, an increase 30 extinction factor impacts approximately 10 %.

Language: Английский

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