scholarly journals Resilience and stability of a pelagic marine ecosystem

2016 ◽  
Vol 283 (1822) ◽  
pp. 20151931 ◽  
Author(s):  
Martin Lindegren ◽  
David M. Checkley ◽  
Mark D. Ohman ◽  
J. Anthony Koslow ◽  
Ralf Goericke
Keyword(s):  
Ecosystem Functioning ◽  
Decadal Variability ◽  
Current System ◽  
Marine Ecosystem ◽  
Experimental Studies ◽  
Trophic Levels ◽  
Environmental Drivers ◽  
California Current System ◽  
Functional Complementarity ◽  
Key Species

The accelerating loss of biodiversity and ecosystem services worldwide has accentuated a long-standing debate on the role of diversity in stabilizing ecological communities and has given rise to a field of research on biodiversity and ecosystem functioning (BEF). Although broad consensus has been reached regarding the positive BEF relationship, a number of important challenges remain unanswered. These primarily concern the underlying mechanisms by which diversity increases resilience and community stability, particularly the relative importance of statistical averaging and functional complementarity. Our understanding of these mechanisms relies heavily on theoretical and experimental studies, yet the degree to which theory adequately explains the dynamics and stability of natural ecosystems is largely unknown, especially in marine ecosystems. Using modelling and a unique 60-year dataset covering multiple trophic levels, we show that the pronounced multi-decadal variability of the Southern California Current System (SCCS) does not represent fundamental changes in ecosystem functioning, but a linear response to key environmental drivers channelled through bottom-up and physical control. Furthermore, we show strong temporal asynchrony between key species or functional groups within multiple trophic levels caused by opposite responses to these drivers. We argue that functional complementarity is the primary mechanism reducing community variability and promoting resilience and stability in the SCCS.

scholarly journals Biodiversity–ecosystem functioning relationships in fish communities: biomass is related to evenness and the environment, not to species richness

2019 ◽  
Vol 286 (1906) ◽  
pp. 20191189 ◽  
Author(s):  
Aurore Maureaud ◽  
Dorothee Hodapp ◽  
P. Daniël van Denderen ◽  
Helmut Hillebrand ◽  
Henrik Gislason ◽  
...  
Keyword(s):  
Species Richness ◽  
Ecosystem Functioning ◽  
Structural Equation ◽  
Fish Assemblages ◽  
Current Knowledge ◽  
Marine Ecosystem ◽  
Experimental Studies ◽  
Fish Communities ◽  
Trophic Levels ◽  
Fish Biomass

The relationship between biodiversity and ecosystem functioning (BEF) is a topic of considerable interest to scientists and managers because a better understanding of its underlying mechanisms may help us mitigate the consequences of biodiversity loss on ecosystems. Our current knowledge of BEF relies heavily on theoretical and experimental studies, typically conducted on a narrow range of spatio-temporal scales, environmental conditions, and trophic levels. Hence, whether a relationship holds in the natural environment is poorly understood, especially in exploited marine ecosystems. Using large-scale observations of marine fish communities, we applied a structural equation modelling framework to investigate the existence and significance of BEF relationships across northwestern European seas. We find that ecosystem functioning, here represented by spatial patterns in total fish biomass, is unrelated to species richness—the most commonly used diversity metric in BEF studies. Instead, community evenness, differences in species composition, and abiotic variables are significant drivers. In particular, we find that high fish biomass is associated with fish assemblages dominated by a few generalist species of a high trophic level, who are able to exploit both the benthic and pelagic energy pathway. Our study provides a better understanding of the mechanisms behind marine ecosystem functioning and allows for the integration of biodiversity into management considerations.

scholarly journals Marine extreme events in high-resolution coupled model simulations

2021 ◽  
Author(s):  
Gesa Eirund ◽  
Matthias Münnich ◽  
Matthieu Leclair ◽  
Nicolas Gruber
Keyword(s):  
High Resolution ◽  
Extreme Events ◽  
Current System ◽  
Current Model ◽  
Marine Ecosystem ◽  
Coupled Model ◽  
Small Scale ◽  
Temporal Scales ◽  
California Current System ◽  
Spatial And Temporal Scales

<p>Air-sea interactions have been found to substantially affect and drive marine extreme events. Such extreme events comprise, among others, highly anomalous conditions in ocean temperature, pH, and oxygen content - all of which are crucial parameters directly impacting marine ecosystem. Nevertheless, our understanding of the role of such events in the marine environment remains limited. In addition, the extent to which the interplay between atmospheric and oceanic forcings impacts the spatial and temporal scales of extreme events and affects the marine ecosystem and ocean biogeochemistry remains largely unknown.</p><p> </p><p>Given these complex interactions between the atmosphere, the ocean, and marine biogeochemistry, we developed a coupled regional high-resolution Earth System Model (ROMSOC). ROMSOC comprises the latest officially released GPU-accelerated Consortium for Small-Scale Modeling (COSMO) version as the atmospheric model, coupled to the Regional Oceanic Modeling System (ROMS). ROMS in turn includes the Biogeochemical Elemental Cycling (BEC) model that describes the functioning of the lower trophic ecosystem in the ocean and the associated biogeochemical cycle. Our current model setup includes thermodynamical coupling and will be extended further to include mechanical coupling between the atmosphere and the ocean. Here, we present first simulations of our coupled model system for the California Current System (CalCS) at the US west coast at kilometer-scale resolution. We will test the hypothesis if the strong mesoscale coupling of the atmosphere and the ocean as represented in our model impacts the spatial and temporal scales of marine heatwaves and can potentially act to shorten their duration.</p>

scholarly journals Trophic interactions among the heterotrophic components of plankton in man-made peat pools

2017 ◽  
Author(s):  
Michał Niedźwiecki ◽  
Malgorzata Adamczuk ◽  
Tomasz Mieczan
Keyword(s):  
Carbon Flux ◽  
Ecosystem Functioning ◽  
Trophic Levels ◽  
Environmental Drivers ◽  
Heterotrophic Nanoflagellates ◽  
Peat Bogs ◽  
Trophic Groups ◽  
Comprehensive Knowledge ◽  
Different Types ◽  
Freshwater Habitats

<p>Man-made peat pools are permanent freshwater habitats developed due to non-commercial man-made peat extraction. Yet, they have not been widely surveyed in terms of ecosystem functioning, mainly regarding the complexity of heterotrophic components of the plankton. In this study we analysed distribution and trophic interrelations among heterotrophic plankton in man-made peat pools located in different types of peatbogs. We found that peat pools showed extreme differences in environmental conditions that occurred to be important drivers of distribution of microplankton and metazooplankton. Abundance of bacteria and protozoa showed significant differences, whereas metazooplankton was less differentiated in density among peat pools. In all peat pools stress-tolerant species of protozoa and metazoa were dominant. In each peat pool five trophic functional groups were distinguished. The abundance of lower functional trophic groups (bacteria, heterotrophic nanoflagellates (HNF) and ciliates feeding on bacteria and HNF) was weakly influenced by environmental drivers and was highly stable in all peat pool types. Higher fu<span style="text-decoration: underline;">n</span>ctional trophic groups (naupli, omnivorous and carnivorous ciliates, cladocerans, adult copepods and copepodites) were strongly influenced by environmental variables and exhibited lower stability. Our study contributes to comprehensive knowledge of the functioning of peat bogs, as our results have shown that peat pools are characterized by high stability of the lowest trophic levels, which can be crucial for energy transfer and carbon flux through food webs.</p>

scholarly journals Biological and environmental drivers of deep-sea benthic ecosystem functioning in Canada’s Laurentian Channel Area of Interest (AOI)

2018 ◽  
Author(s):  
Marta Miatta ◽  
Paul V Snelgrove
Keyword(s):  
Deep Sea ◽  
Ecosystem Functioning ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Marine Ecosystem ◽  
Environmental Drivers ◽  
Biological Traits ◽  
Area Of Interest ◽  
Prokaryotic Abundance

Ongoing environmental changes and accelerating biodiversity loss raise concern and interest about the role of environmental factors and biodiversity in determining marine ecosystem functioning. This study aims to identify the main drivers of benthic ecosystem functioning in deep-sea sedimentary habitats in the Laurentian Channel Area of Interest (AOI), and in particular the role of sea pens (Pennatulacea) as potential keystone species in the area. Using the ROV ROPOS we collected sediment cores and measured environmental variables from 6 stations inside the AOI (depths 348–445m) in September 2017. Through 48-hours incubations and flux measurements (oxygen, inorganic nutrients), we estimated organic matter remineralization, a key benthic function. Preliminary analyses show no significant variation in fluxes among stations, despite significant differences in environmental variables However, the presence/absence of Pennatulacea inside the cores indicated some capability to enhance remineralization and particularly nitrification. Ongoing analyses will address sediment properties, macrofaunal biodiversity, prokaryotic abundance, and biological traits as drivers of remineralization. Shedding new light on the primary drivers of ecosystem functioning in the area will inform the design or monitoring strategies proposed for this AOI and offer new perspectives and tools for MPA design.

scholarly journals Climate-driven aerobic habitat loss in the California Current System

2020 ◽  
Vol 6 (20) ◽  
pp. eaay3188 ◽  
Author(s):  
Evan M. Howard ◽  
Justin L. Penn ◽  
Hartmut Frenzel ◽  
Brad A. Seibel ◽  
Daniele Bianchi ◽  
...  
Keyword(s):  
Habitat Loss ◽  
Current System ◽  
Marine Ecosystem ◽  
Oxygen Demand ◽  
California Current ◽  
Regional Variability ◽  
California Current System ◽  
Large Fluctuations ◽  
Northern Anchovy ◽  
Species Specific

Climate warming is expected to intensify hypoxia in the California Current System (CCS), threatening its diverse and productive marine ecosystem. We analyzed past regional variability and future changes in the Metabolic Index (Φ), a species-specific measure of the environment’s capacity to meet temperature-dependent organismal oxygen demand. Across the traits of diverse animals, Φ exhibits strong seasonal to interdecadal variations throughout the CCS, implying that resident species already experience large fluctuations in available aerobic habitat. For a key CCS species, northern anchovy, the long-term biogeographic distribution and decadal fluctuations in abundance are both highly coherent with aerobic habitat volume. Ocean warming and oxygen loss by 2100 are projected to decrease Φ below critical levels in 30 to 50% of anchovies’ present range, including complete loss of aerobic habitat—and thus likely extirpation—from the southern CCS. Aerobic habitat loss will vary widely across the traits of CCS taxa, disrupting ecological interactions throughout the region.

scholarly journals Biological and environmental drivers of deep-sea benthic ecosystem functioning in Canada’s Laurentian Channel Area of Interest (AOI)

2018 ◽  
Author(s):  
Marta Miatta ◽  
Paul V Snelgrove
Keyword(s):  
Deep Sea ◽  
Ecosystem Functioning ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Marine Ecosystem ◽  
Environmental Drivers ◽  
Biological Traits ◽  
Area Of Interest ◽  
Prokaryotic Abundance

Ongoing environmental changes and accelerating biodiversity loss raise concern and interest about the role of environmental factors and biodiversity in determining marine ecosystem functioning. This study aims to identify the main drivers of benthic ecosystem functioning in deep-sea sedimentary habitats in the Laurentian Channel Area of Interest (AOI), and in particular the role of sea pens (Pennatulacea) as potential keystone species in the area. Using the ROV ROPOS we collected sediment cores and measured environmental variables from 6 stations inside the AOI (depths 348–445m) in September 2017. Through 48-hours incubations and flux measurements (oxygen, inorganic nutrients), we estimated organic matter remineralization, a key benthic function. Preliminary analyses show no significant variation in fluxes among stations, despite significant differences in environmental variables However, the presence/absence of Pennatulacea inside the cores indicated some capability to enhance remineralization and particularly nitrification. Ongoing analyses will address sediment properties, macrofaunal biodiversity, prokaryotic abundance, and biological traits as drivers of remineralization. Shedding new light on the primary drivers of ecosystem functioning in the area will inform the design or monitoring strategies proposed for this AOI and offer new perspectives and tools for MPA design.

scholarly journals Essential krill species habitat resolved by seasonal upwelling and ocean circulation models within the large marine ecosystem of the California Current System

Ecography ◽  
2020 ◽  
Vol 43 (10) ◽  
pp. 1536-1549
Author(s):  
Megan A. Cimino ◽  
Jarrod A. Santora ◽  
Isaac Schroeder ◽  
William Sydeman ◽  
Michael G. Jacox ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Current System ◽  
Marine Ecosystem ◽  
California Current ◽  
California Current System ◽  
Large Marine Ecosystem

scholarly journals A monthly surface pCO<sub>2</sub> product for the California Current Large Marine Ecosystem

2021 ◽  
Author(s):  
Jonathan D. Sharp ◽  
Andrea J. Fassbender ◽  
Brendan R. Carter ◽  
Paige D. Lavin ◽  
Adrienne J. Sutton
Keyword(s):  
Current System ◽  
Marine Ecosystem ◽  
California Current ◽  
Co2 Exchange ◽  
Coastal Ocean ◽  
California Current System ◽  
Spatial And Temporal Scales ◽  
Data Product ◽  
Spatially Resolved ◽  
Carbon Dioxide Gas

Abstract. To calculate the direction and rate of carbon dioxide gas (CO2) exchange between the ocean and atmosphere, it is critical to know the partial pressure of CO2 in surface seawater (pCO2(sw)). Over the last decade, a variety of data products of global monthly pCO2(sw) have been produced, primarily for the open ocean on 1° latitude by 1° longitude grids. More recently, monthly products of pCO2(sw) that are more finely spatially resolved in the coastal ocean have been made available. A remaining challenge in the development of pCO2(sw) products is the robust characterization of seasonal variability, especially in nearshore coastal environments. Here we present a monthly data product of pCO2(sw) at 0.25° latitude by 0.25° longitude resolution in the Northeast Pacific Ocean, centered around the California Current System (CCS). The data product (RFR-CCS; Sharp et al., 2021; https://doi.org/10.5281/zenodo.5523389) was created using the most recent (2021) version of the Surface Ocean CO2 Atlas (Bakker et al., 2016) from which pCO2(sw) observations were extracted and fit against a variety of satellite- and model-derived surface variables using a random forest regression (RFR) model. We validate RFR-CCS in multiple ways, including direct comparisons with observations from moored autonomous surface platforms, and find that the data product effectively captures seasonal pCO2(sw) cycles at nearshore mooring sites. This result is notable because alternative global products for the coastal ocean do not capture local variability effectively in this region. We briefly review the physical and biological processes — acting across a variety of spatial and temporal scales — that are responsible for the latitudinal and nearshore-to-offshore pCO2(sw) gradients seen in RFR-CCS reconstructions of pCO2(sw).

scholarly journals Modeling changes in baleen whale seasonal abundance, timing of migration, and environmental variables to explain the sudden rise in entanglements in California

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0248557
Author(s):  
Kaytlin Ingman ◽  
Ellen Hines ◽  
Piero L. F. Mazzini ◽  
R. Cotton Rockwood ◽  
Nadav Nur ◽  
...  
Keyword(s):  
Negative Binomial ◽  
Southern Oscillation ◽  
Current System ◽  
Seasonal Abundance ◽  
Environmental Drivers ◽  
California Current System ◽  
Central California ◽  
Early Arrival ◽  
Basin Scale ◽  
Timing Of Migration

We document changes in the number of sightings and timing of humpback (Megaptera novaeangliae), blue (Balaenoptera musculus), and gray (Eschrichtius robustus) whale migratory phases in the vicinity of the Farallon Islands, California. We hypothesized that changes in the timing of migration off central California were driven by local oceanography, regional upwelling, and basin-scale climate conditions. Using 24 years of daily whale counts collected from Southeast Farallon Island, we developed negative binomial regression models to evaluate trends in local whale sightings over time. We then used linear models to assess trends in the timing of migration, and to identify potential environmental drivers. These drivers included local, regional and basin-scale patterns; the latter included the El Niño Southern Oscillation, the Pacific Decadal Oscillation, and the North Pacific Gyre Oscillation, which influence, wind-driven upwelling, and overall productivity in the California Current System. We then created a forecast model to predict the timing of migration. Humpback whale sightings significantly increased over the study period, but blue and gray whale counts did not, though there was variability across the time series. Date of breeding migration (departure) for all species showed little to no change, whereas date of migration towards feeding areas (arrival) occurred earlier for humpback and blue whales. Timing was significantly influenced by a mix of local oceanography, regional, and basin-scale climate variables. Earlier arrival time without concomitant earlier departure time results in longer periods when blue and humpback whales are at risk of entanglement in the Gulf of the Farallones. We maintain that these changes have increased whale exposure to pot and trap fishery gear off the central California coast during the spring, elevating the risk of entanglements. Humpback entanglement rates were significantly associated with increased counts and early arrival in central California. Actions to decrease the temporal overlap between whales and pot/trap fishing gear, particularly when whales arrive earlier in warm water years, would likely decrease the risk of entanglements.

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