Forecasting ocean acidification impacts on kelp forest ecosystems

Ocean acidification is one the biggest threats to marine ecosystems worldwide, but its ecosystem wide responses are still poorly understood. This study integrates field and experimental data into a mass balance food web model of a temperate coastal ecosystem to determine the impacts of specific OA forcing mechanisms as well as how they interact with one another. Specifically, we forced a food web model of a kelp forest ecosystem near its southern distribution limit in the California large marine ecosystem to a 0.5 pH drop over the course of 50 years. This study utilizes a modeling approach to determine the impacts of specific OA forcing mechanisms as well as how they interact. Isolating OA impacts on growth (Production), mortality (Other Mortality), and predation interactions (Vulnerability) or combining all three mechanisms together leads to a variety of ecosystem responses, with some taxa increasing in abundance and other decreasing. Results suggest that carbonate mineralizing groups such as coralline algae, abalone, snails, and lobsters display the largest decreases in biomass while macroalgae, urchins, and some larger fish species display the largest increases. Low trophic level groups such as giant kelp and brown algae increase in biomass by 16% and 71%, respectively. Due to the diverse way in which OA stress manifests at both individual and population levels, ecosystem-level effects can vary and display nonlinear patterns. Combined OA forcing leads to initial increases in ecosystem and commercial biomasses followed by a decrease in commercial biomass below initial values over time, while ecosystem biomass remains high. Both biodiversity and average trophic level decrease over time. These projections indicate that the kelp forest community would maintain high productivity with a 0.5 drop in pH, but with a substantially different community structure characterized by lower biodiversity and relatively greater dominance by lower trophic level organisms.

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Forecasting ocean acidification impacts on kelp forest ecosystems

10.1101/2020.07.03.186239 ◽

2020 ◽

Author(s):

Adam J. Schlenger ◽

Rodrigo Beas-Luna ◽

Richard F. Ambrose

Keyword(s):

Ocean Acidification ◽

Food Web ◽

Trophic Level ◽

Marine Ecosystem ◽

Kelp Forest ◽

Forest Community ◽

Coralline Algae ◽

Forcing Mechanisms ◽

Over Time ◽

Food Web Model

AbstractOcean acidification is one the biggest threats to marine ecosystems worldwide, but its ecosystem wide responses are still poorly understood. This study integrates field and experimental data into a mass balance food web model of a temperate coastal ecosystem to determine the impacts of specific OA forcing mechanisms as well as how they interact with one another. Specifically, we forced a food web model of a kelp forest ecosystem near its southern distribution limit in the California large marine ecosystem to a 0.5 pH drop over the course of 50 years. This study utilizes a modeling approach to determine the impacts of specific OA forcing mechanisms as well as how they interact. Isolating OA impacts on growth (Production), mortality (Other Mortality), and predation interactions (Vulnerability) or combining all three mechanisms together leads to a variety of ecosystem responses, with some taxa increasing in abundance and other decreasing. Results suggest that carbonate mineralizing groups such as coralline algae, abalone, snails, and lobsters display the largest decreases in biomass while macroalgae, urchins, and some larger fish species display the largest increases. Low trophic level groups such as giant kelp and brown algae increase in biomass by 16% and 71%, respectively. Due to the diverse way in which OA stress manifests at both individual and population levels, ecosystem-level effects can vary and display nonlinear patterns. Combined OA forcing leads to initial increases in ecosystem and commercial biomasses followed by a decrease in commercial biomass below initial values over time, while ecosystem biomass remains high. Both biodiversity and average trophic level decrease over time. These projections indicate that the kelp forest community would maintain high productivity with a 0.5 drop in pH, but with a substantially different community structure characterized by lower biodiversity and relatively greater dominance by lower trophic level organisms.

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A mass-balanced food web model for a kelp forest ecosystem near its southern distributional limit in the northern hemisphere

Food Webs ◽

10.1016/j.fooweb.2018.e00091 ◽

2018 ◽

Vol 17 ◽

pp. e00091 ◽

Cited By ~ 2

Author(s):

Ainoa Vilalta-Navas ◽

Rodrigo Beas-Luna ◽

Luis E. Calderon-Aguilera ◽

Lydia Ladah ◽

Fiorenza Micheli ◽

...

Keyword(s):

Food Web ◽

Northern Hemisphere ◽

Forest Ecosystem ◽

Kelp Forest ◽

Distributional Limit ◽

Food Web Model

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Stable Isotope Analyses of Multiple Tissues of Great Shearwaters (Ardenna Gravis) Reveals Long-Term Dietary Stability, Short-Term Changes in Diet, and Can be Used as a Tool to Monitor Food Webs

Diversity ◽

10.3390/d11090163 ◽

2019 ◽

Vol 11 (9) ◽

pp. 163 ◽

Cited By ~ 1

Author(s):

Hong ◽

Wiley ◽

Powers ◽

Michener ◽

Kaufman ◽

...

Keyword(s):

Stable Isotope ◽

Food Web ◽

Food Webs ◽

Trophic Level ◽

Isotope Analysis ◽

Diet Shift ◽

Turnover Rates ◽

Δ13c And Δ15n ◽

Isotopic Signatures ◽

Over Time

The great shearwater (Ardenna gravis) is a common pelagic bird with a distribution that spans almost the entire Atlantic basin, which in conjunction with its relatively high abundance, makes great shearwaters an effective bio indicator. We compared δ13C and δ15N values from the feathers, red blood cells (RBCs), and plasma of great shearwaters collected in 2014 and 2015 from the waters off Massachusetts and Cape Cod. The δ13C and δ15N values of RBCs were quite constant between sampling periods and years, suggesting a generally stable food web over that time period. However, the δ13C of plasma indicates a small seasonal change in diet between July and September for both years, with plasma δ15N values suggesting a slight increase in trophic level late in summer. Comparison of the δ15N of RBCs and plasma indicates that great shearwaters experienced a diet shift during the first few weeks of summer 2014, but not in 2015. Comparisons with other studies suggest that these shearwaters feed at a lower trophic level than great shearwaters sampled in the Bay of Fundy and that there is a decrease in δ13C with increasing latitude, which could indicate a more pelagic diet in northern waters. Stable isotope analysis of the sixth primary feathers provided evidence that these feathers are molted in the Northern Hemisphere and that the diet of great shearwaters shortly after arrival was different in 2014 and 2015. This study demonstrates that within species comparisons of tissue isotopic signatures over time and comparisons of isotopic signatures of tissues with different turnover rates, can detect changes in diet and be used as a tool to monitor for changes in marine food webs over time and space. The relevant signals remain informative even in the absence of species-specific data on tissue-diet discrimination factors, tissue turnover rates, or knowledge of dietary components and their stable isotopic signatures, suggesting dietary changes indicative of a corresponding change in the food web.

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Impact of Ocean Acidification on Ecosystem Functioning and Services in Habitat-Forming Species and Marine Ecosystems

Ecosystems ◽

10.1007/s10021-021-00601-3 ◽

2021 ◽

Author(s):

Serena Zunino ◽

Simone Libralato ◽

Donata Melaku Canu ◽

Giulia Prato ◽

Cosimo Solidoro

Keyword(s):

Ecosystem Services ◽

Ocean Acidification ◽

Food Web ◽

Marine Protected Area ◽

Habitat Degradation ◽

Marine Ecosystem ◽

Ecosystem Model ◽

Posidonia Oceanica ◽

Ecosystem Development ◽

Cascading Effects

AbstractOcean acidification (OA) is expected to impact habitat-forming species (HFS), with cascading effects on the whole marine ecosystem and related services that are seldom quantified. Here, the changes in HFSs biomass due to OA are modeled using a food web ecosystem model, and the trophic and non-trophic cascading effects on the marine community are investigated. The food web model represents a well-studied coastal marine protected area in the NW Mediterranean Sea where coralligenous reefs and Posidonia oceanica meadows constitute important HFS. The model is used to implement 5 scenarios of habitat degradation, that is, reduction of HFS biomass, induced by increasing OA and to quantify the potential changes in ecosystem properties and indicators of ecosystem services over the next 100 years. The changes in ecosystem indicators highlight a decrease in the size of the system and a reorganization of energy flows suggesting a high degree of ecosystem development. All the proxies for ecosystem services show significant decreases in their values. Although representing only a portion of the possible impacts of OA, the findings are consistent with the idea that ecological systems can react to OA effects to maintain the level of ecosystem development, but the new organization might not be optimal from an anthropocentric viewpoint.

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Fishing down then up the food web of an invaded lake

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1908272116 ◽

2019 ◽

Vol 116 (40) ◽

pp. 19995-20001 ◽

Cited By ~ 1

Author(s):

Erin S. Dunlop ◽

Daisuke Goto ◽

Donald A. Jackson

Keyword(s):

Invasive Species ◽

Food Web ◽

Trophic Level ◽

Fishing Effort ◽

Striking Difference ◽

Recreational Fishing ◽

Historical Period ◽

Commercial Fishing ◽

Ecosystem Impacts ◽

Over Time

Analysis of commercial catches reveals a serial depletion of some oceanic fish stocks over time, resulting in fisheries focusing on increasingly smaller species closer to the base of the food chain. This effect, described as fishing down the marine food web, is observed when the trophic level of the catch declines over time, raising concerns about the ecosystem impacts of fishing. Freshwater systems also experience harvest, yet do not appear to commonly show the same fishing down response perhaps because time series are too short to witness early depletions, fishing is often recreational, or other factors like stocking and invasive species influence patterns. Here we make use of extensive catch records from Lake Simcoe dating back to the 1860s, to examine if fishing down effects are observed in this highly exploited Canadian inland lake. We measured 2 commonly used indicators from catch data, mean trophic level (MTL) and fishing-in-balance (FiB), and compared trends between a historical period dominated by commercial fishing and a contemporary period when commercial fishing ceased and recreational fishing effort increased. We found a striking difference between the 2 time periods, with MTL (and to some extent FiB) declining during commercial fishing but increasing during recreational fishing. However, indicators either increased or decreased due to invasive species and increased due to stocking. We show that while declining MTL can occur in a freshwater lake, the trajectory can be altered by a switch to recreational fishing, as well as stocking and invasive species.

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Trophic level, food chain length and omnivory in the Paraná River: a food web model approach in a floodplain river system

Ecological Research ◽

10.1007/s11284-015-1283-1 ◽

2015 ◽

Vol 30 (5) ◽

pp. 843-852 ◽

Cited By ~ 13

Author(s):

M. Saigo ◽

F. L. Zilli ◽

M. R. Marchese ◽

D. Demonte

Keyword(s):

Food Web ◽

Chain Length ◽

Trophic Level ◽

Food Chain ◽

River System ◽

Parana River ◽

Floodplain River ◽

Food Chain Length ◽

Food Web Model ◽

Model Approach

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Potential impacts of ocean acidification on the Puget Sound food web

ICES Journal of Marine Science ◽

10.1093/icesjms/fst061 ◽

2013 ◽

Vol 70 (4) ◽

pp. 823-833 ◽

Cited By ~ 31

Author(s):

D. Shallin Busch ◽

Chris J. Harvey ◽

Paul McElhany

Keyword(s):

Ocean Acidification ◽

Food Web ◽

Indirect Effects ◽

Puget Sound ◽

Direct And Indirect Effects ◽

Direct Effects ◽

Ecosystem Impacts ◽

Complex Interactions ◽

Species Groups ◽

Food Web Model

Abstract Busch, D. S., Harvey, C. J., and McElhany, P. 2013. Potential impacts of ocean acidification on the Puget Sound food web. – ICES Journal of Marine Science, 70: 823–833. Ecosystem impacts of ocean acidification (OA) were explored by imposing scenarios designed to mimic OA on a food web model of Puget Sound, a large estuary in northwestern USA. The productivity of functional groups containing mostly calcifiers was decreased while still allowing other species groups to respond to the scenarios in a dynamic way through indirect effects. Results focus on changes in ecosystem services and structure. Sometimes the direct and indirect effects of OA countered each other due to interactions between predators and prey within the food web, leading to little change in the food web. In other cases, direct and indirect effects caused greater change in the food web than anticipated from direct effects alone. Results were strongly affected by the group on which OA was directly imposed, with changes in copepod productivity being the most influential. While there is much uncertainty in our predictions, focusing on the complex interactions among species, and between species and their environment, will yield better understanding of how ecosystems may respond to OA.

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