scholarly journals Trophic level decoupling drives future change in phytoplankton bloom phenology

2021 ◽  
Author(s):  
Ryohei Yamaguchi ◽  
Keith Rodgers ◽  
Karl Stein ◽  
Axel Timmermann ◽  
Sarah Schlunegger ◽  
...  
Keyword(s):  
Climate Change ◽  
Phytoplankton Bloom ◽  
Marine Ecosystem ◽  
Growth Period ◽  
Trophic Levels ◽  
Global Ocean ◽  
High Latitudes ◽  
Future Change ◽  
Climate Change Projections ◽  
The Tropics

Abstract Anthropogenic climate change is affecting marine ecosystems by altering the strength of phytoplankton blooms and driving shifts in the seasonality (phenology) of productivity. Here, we analyze a new 30-member Large Ensemble of climate change projections to quantify the sensitivity of phytoplankton bloom phenology (initiation, peak timing, and net growth period length) to anthropogenic forcing. Forced changes in the duration of net growth vary widely across the global ocean, with high latitudes experiencing a reduction of up to one month, and the tropics and subtropics experiencing an extension of up to one month. Changes in duration reflect shifts in both bloom initiation and peak bloom timing, which result from subtle decoupling between phytoplankton growth and zooplankton predation driven by temperature, nutrients and light variations. Changes in bloom strength and timing will alter the flow of energy in the marine ecosystem, with implications for higher trophic levels and fisheries.

scholarly journals Global ensemble projections reveal trophic amplification of ocean biomass declines with climate change

2019 ◽  
Vol 116 (26) ◽  
pp. 12907-12912 ◽  
Author(s):  
Heike K. Lotze ◽  
Derek P. Tittensor ◽  
Andrea Bryndum-Buchholz ◽  
Tyler D. Eddy ◽  
William W. L. Cheung ◽  
...  
Keyword(s):  
Climate Change ◽  
Human Impacts ◽  
Marine Ecosystem ◽  
Model Development ◽  
Trophic Levels ◽  
Global Ocean ◽  
Earth System ◽  
System Models ◽  
Earth System Models ◽  
Ensemble Projections

While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. We derive average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% (±4% SD) under low emissions and 17% (±11% SD) under high emissions by 2100, with an average 5% decline for every 1 °C of warming. Projected biomass declines were primarily driven by increasing temperature and decreasing primary production, and were more pronounced at higher trophic levels, a process known as trophic amplification. Fishing did not substantially alter the effects of climate change. Considerable regional variation featured strong biomass increases at high latitudes and decreases at middle to low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to variations in marine ecosystem and Earth system models were similar. Ensemble projections performed well compared with empirical data, emphasizing the benefits of multimodel inference to project future outcomes. Our results indicate that global ocean animal biomass consistently declines with climate change, and that these impacts are amplified at higher trophic levels. Next steps for model development include dynamic scenarios of fishing, cumulative human impacts, and the effects of management measures on future ocean biomass trends.

scholarly journals Emergence of multiple ocean ecosystem drivers in a large ensemble suite with an Earth system model

2015 ◽  
Vol 12 (11) ◽  
pp. 3301-3320 ◽  
Author(s):  
K. B. Rodgers ◽  
J. Lin ◽  
T. L. Frölicher
Keyword(s):  
Southern Ocean ◽  
Marine Ecosystem ◽  
Marine Ecosystems ◽  
Earth System Model ◽  
System Model ◽  
Global Ocean ◽  
Earth System ◽  
Biological Productivity ◽  
The Tropics ◽  
Ecosystem Drivers

Abstract. Marine ecosystems are increasingly stressed by human-induced changes. Marine ecosystem drivers that contribute to stressing ecosystems – including warming, acidification, deoxygenation and perturbations to biological productivity – can co-occur in space and time, but detecting their trends is complicated by the presence of noise associated with natural variability in the climate system. Here we use large initial-condition ensemble simulations with an Earth system model under a historical/RCP8.5 (representative concentration pathway 8.5) scenario over 1950–2100 to consider emergence characteristics for the four individual and combined drivers. Using a 1-standard-deviation (67% confidence) threshold of signal to noise to define emergence with a 30-year trend window, we show that ocean acidification emerges much earlier than other drivers, namely during the 20th century over most of the global ocean. For biological productivity, the anthropogenic signal does not emerge from the noise over most of the global ocean before the end of the 21st century. The early emergence pattern for sea surface temperature in low latitudes is reversed from that of subsurface oxygen inventories, where emergence occurs earlier in the Southern Ocean. For the combined multiple-driver field, 41% of the global ocean exhibits emergence for the 2005–2014 period, and 63% for the 2075–2084 period. The combined multiple-driver field reveals emergence patterns by the end of this century that are relatively high over much of the Southern Ocean, North Pacific, and Atlantic, but relatively low over the tropics and the South Pacific. For the case of two drivers, the tropics including habitats of coral reefs emerges earliest, with this driven by the joint effects of acidification and warming. It is precisely in the regions with pronounced emergence characteristics where marine ecosystems may be expected to be pushed outside of their comfort zone determined by the degree of natural background variability to which they are adapted. The results underscore the importance of sustained multi-decadal observing systems for monitoring multiple ecosystems drivers.

scholarly journals Distribution of mesozooplankton biomass in the global ocean

2012 ◽  
Vol 5 (2) ◽  
pp. 893-919
Author(s):  
R. Moriarty ◽  
T. D. O'Brien
Keyword(s):  
Marine Ecosystem ◽  
Original Data ◽  
Dry Mass ◽  
Global Ocean ◽  
Ecosystem Models ◽  
Mesozooplankton Biomass ◽  
Carbon Biomass ◽  
Community Effort ◽  
Marine Ecosystem Models ◽  
The Tropics

Abstract. Mesozooplankton are cosmopolitan within the sunlit layers of the global ocean. They are important in the classical food web, having a significant feedback to primary production through their consumption of phytoplankton and microzooplankton. They are also the primary contributor to vertical particle flux in the oceans. Through both they affect the biogeochemical cycling of carbon and other nutrients in the oceans. Little, however, is known about their global distribution and biomass. While global maps of mesozooplankton biomass do exist in the literature they are usually in the form of hand-drawn maps and the original data associated with these maps are not readily available. The dataset presented in this synthesis has been in development since the late 1990's, is an integral part of the Coastal & Oceanic Plankton Ecology, Production, & Observation Database (COPEPOD), and is now also part of a wider community effort to provide a global picture of carbon biomass data for key plankton functional types, in particular to support the development of marine ecosystem models. A total of 153 163 biomass values were collected, from a variety of sources, for mesozooplankton. Of those 2% were originally recorded as dry mass, 26% as wet mass, 5% as settled volume, and 68% as displacement volume. Using a variety of non-linear biomass conversions from the literature, the data have been converted from their original units to carbon biomass. Depth-integrated values were then used to calculate mesozooplankton global biomass. Global mesozooplankton biomass, to a depth of 200 m, had a mean of 5.9 μg C l−1, median of 2.7 μg C l−1 and a standard deviation of 10.6 μg C l−1. The global annual average estimate of mesozooplankton, based on the median value, was 0.19 Pg C. Biomass was highest in the Northern Hemisphere, but the general trend shows a slight decrease from polar oceans to temperate regions with values increasing again in the tropics. Gridded dataset http://doi.pangaea.de/10.1594/PANGAEA.785501x.

Impact of biogeochemistry feedbacks on the projected climate change signal over the Indian Continent

2020 ◽  
Author(s):  
Dmitry Sein ◽  
William Cabos ◽  
Pankaj Kumar ◽  
Vladimir Ryabchenko ◽  
Stanislav Martyanov ◽  
...  
Keyword(s):  
Climate Change ◽  
Marine Ecosystem ◽  
Regional Model ◽  
Ocean Model ◽  
Global Ocean ◽  
Future Climate Change ◽  
Climate Change Signal ◽  
Water Type ◽  
Substantial Impact ◽  
The Impact

<p>There are few studies dedicated to assessing the impact of biogeochemistry feedbacks on the climate change signal. In this study, we evaluate this impact in a future climate change scenario over the Indian subcontinent with the coupled regional model ROM in the Indian CORDEX area.In ROM a global ocean model (MPIOM) with regionally high horizontal resolution (up to 15 km resolution in the Bay of Bengal) is coupled to an atmospheric regional model (REMO, with 25 km resolution) and global terrestrial hydrology model. The ocean and the atmosphere are interacting within the region covered by the atmospheric domain. Outside this domain, the ocean model is not coupled to the atmosphere, being driven by prescribed atmospheric forcing, thus running in so-called stand-alone mode.</p><p>To assess the impact of biogeochemical feedbacks on the climate change signal, we compare two simulations with ROM. In both simulations, the model is driven by data from a climate change simulation under the RCP 8.5 scenario with the MPI-ESM global model and differ only in the activation of the biochemistry module of MPIOM. In the first simulation, we use a light attenuation parameterization based on the Jerlov water types, when the attenuation coefficient varies spatially depending on the water type specified but does not vary in time. In the second simulation, we introduce the biochemical feedbacks as implemented in the global ocean biogeochemistry model HAMOCC.  </p><p>Both simulations capture the main features of the present time atmospheric and oceanic variability in the region and the model with HAMOCC reproduces well the intra-annual dynamics of the marine ecosystem in the northern Indian Ocean.</p><p>A comparison of the simulated changes in atmospheric variables shows that the feedbacks have a substantial impact on the climate change signal for precipitation and air temperature, especially over the central Indian region.</p><p>Acknowledgement: The work was supported by the Russian Science Foundation (Project 19-47-02015) and Indian project no. DST/INT/RUS/RSF/P-33/G.</p>

Changes in the Antarctic sea ice ecosystem: potential effects on krill and baleen whales

2008 ◽  
Vol 59 (5) ◽  
pp. 361 ◽  
Author(s):  
Stephen Nicol ◽  
Anthony Worby ◽  
Rebecca Leaper
Keyword(s):  
Climate Change ◽  
Southern Ocean ◽  
Sea Ice ◽  
Ocean Circulation ◽  
Trophic Levels ◽  
Global Ocean ◽  
Ecological Change ◽  
Cetacean Species ◽  
Baleen Whales ◽  
The Antarctic

The annual formation and loss of some 15 million km2 of sea ice around the Antarctic significantly affects global ocean circulation, particularly through the formation of dense bottom water. As one of the most profound seasonal changes on Earth, the formation and decay of sea ice plays a major role in climate processes. It is also likely to be impacted by climate change, potentially changing the productivity of the Antarctic region. The sea ice zone supports much wildlife, particularly large vertebrates such as seals, seabirds and whales, some exploited to near extinction. Cetacean species in the Southern Ocean will be directly impacted by changes in sea ice patterns as well as indirectly by changes in their principal prey, Antarctic krill, affected by modifications to their own environment through climate change. Understanding how climate change will affect species at all trophic levels in the Southern Ocean requires new approaches and integrated research programs. This review focuses on the current state of knowledge of the sea ice zone and examines the potential for climatic and ecological change in the region. In the context of changes already documented for seals and seabirds, it discusses potential effects on the most conspicuous vertebrate of the region, baleen whales.

scholarly journals Distribution of known macrozooplankton abundance and biomass in the global ocean

2013 ◽  
Vol 5 (2) ◽  
pp. 241-257 ◽  
Author(s):  
R. Moriarty ◽  
E. T. Buitenhuis ◽  
C. Le Quéré ◽  
M.-P. Gosselin
Keyword(s):  
Marine Ecosystem ◽  
Deep Ocean ◽  
Distribution Patterns ◽  
Data Depth ◽  
Trophic Levels ◽  
Global Ocean ◽  
Abundance Data ◽  
Carbon Biomass ◽  
Lack Of Information ◽  
Species Specific

Abstract. Macrozooplankton are an important link between higher and lower trophic levels in the oceans. They serve as the primary food for fish, reptiles, birds and mammals in some regions, and play a role in the export of carbon from the surface to the intermediate and deep ocean. Little, however, is known of their global distribution and biomass. Here we compiled a dataset of macrozooplankton abundance and biomass observations for the global ocean from a collection of four datasets. We harmonise the data to common units, calculate additional carbon biomass where possible, and bin the dataset in a global 1 × 1 degree grid. This dataset is part of a wider effort to provide a global picture of carbon biomass data for key plankton functional types, in particular to support the development of marine ecosystem models. Over 387 700 abundance data and 1330 carbon biomass data have been collected from pre-existing datasets. A further 34 938 abundance data were converted to carbon biomass data using species-specific length frequencies or using species-specific abundance to carbon biomass data. Depth-integrated values are used to calculate known epipelagic macrozooplankton biomass concentrations and global biomass. Global macrozooplankton biomass, to a depth of 350 m, has a mean of 8.4 μg C L−1, median of 0.2 μg C L−1 and a standard deviation of 63.5 μg C L−1. The global annual average estimate of macrozooplankton biomass in the top 350 m, based on the median value, is 0.02 Pg C. There are, however, limitations on the dataset; abundance observations have good coverage except in the South Pacific mid-latitudes, but biomass observation coverage is only good at high latitudes. Biomass is restricted to data that is originally given in carbon or to data that can be converted from abundance to carbon. Carbon conversions from abundance are restricted by the lack of information on the size of the organism and/or the absence of taxonomic information. Distribution patterns of global macrozooplankton biomass and statistical information about biomass concentrations may be used to validate biogeochemical and plankton functional type models. Macrozooplankton abundance and biomass dataset doi:10.1594/PANGAEA.777398.

scholarly journals Distribution of known macrozooplankton abundance and biomass in the global ocean

2012 ◽  
Vol 5 (1) ◽  
pp. 187-220 ◽  
Author(s):  
R. Moriarty ◽  
E. T. Buitenhuis ◽  
C. Le Quéré ◽  
M.-P. Gosselin
Keyword(s):  
Marine Ecosystem ◽  
Deep Ocean ◽  
Data Depth ◽  
Trophic Levels ◽  
Global Ocean ◽  
Abundance Data ◽  
Carbon Biomass ◽  
Biogeochemical Models ◽  
Original Dataset ◽  
Species Specific

Abstract. Macrozooplankton are an important link between higher and lower trophic levels in the oceans. They serve as the primary food for fish, reptiles, birds and mammals in some regions, and play a role in the export of carbon from the surface to the intermediate and deep ocean. Little, however, is known of their global distribution and biomass. Here we compiled a dataset of macrozooplankton abundance and biomass observations for the global ocean from a collection of four datasets. We harmonise the data to common units, calculate additional carbon biomass where possible, and bin the dataset in a global 1 × 1 degree grid. This dataset is part of a wider effort to provide a global picture of carbon biomass data for key plankton functional types, in particular to support the development of marine ecosystem models. Over 387 700 abundance data and 1330 carbon biomass data have been collected from pre-existing datasets. A further 34 938 abundance data were converted to carbon biomass data using species-specific length frequencies or using species-specific abundance to carbon biomass data. Depth-integrated values are used to calculate known epipelagic macrozooplankton biomass concentrations and global biomass. Global macrozooplankton biomass has a mean of 8.4 μg C l−1, median of 0.15 μg C l−1 and a standard deviation of 63.46 μg C l−1. The global annual average estimate of epipelagic macrozooplankton, based on the median value, is 0.02 Pg C. Biomass is highest in the tropics, decreasing in the sub-tropics and increasing slightly towards the poles. There are, however, limitations on the dataset; abundance observations have good coverage except in the South Pacific mid latitudes, but biomass observation coverage is only good at high latitudes. Biomass is restricted to data that is originally given in carbon or to data that can be converted from abundance to carbon. Carbon conversions from abundance are restricted in the most part by the lack of information on the size of the organism and/or the absence of taxonomic information. Distribution patterns of global macrozooplankton biomass and statistical information about biomass concentrations may be used to validate biogeochemical models and Plankton Functional Type models. Original dataset http://doi.pangaea.de/10.1594/PANGAEA.777398 Gridded dataset http://doi.pangaea.de/10.1594/PANGAEA.777398

scholarly journals Effects of Climate Change in Marine Ecosystems Based on the Spatiotemporal Age Structure of Top Predators: A Case Study of Bigeye Tuna in the Pacific Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Kuo-Wei Lan ◽  
Yan-Lun Wu ◽  
Lu-Chi Chen ◽  
Muhamad Naimullah ◽  
Tzu-Hsiang Lin
Keyword(s):  
Climate Change ◽  
Pacific Ocean ◽  
Marine Ecosystem ◽  
Trophic Levels ◽  
Bigeye Tuna ◽  
Central Pacific ◽  
Bottom Up ◽  
Top Predators ◽  
The Pacific

How top predators behave and are distributed depend on the conditions in their marine ecosystem through bottom−up forcing; this is because where and when these predators can feed and spawn are limited and change often. This study investigated how the catch rates of immature and mature cohorts of bigeye tuna (BET) varied across space and time; this was achieved by analyzing data on the Taiwanese longline fishery in the western and central Pacific Ocean (WCPO). We also conducted a case study on the time series patterns of BET cohorts to explore the processes that underlie the bottom-up control of the pelagic ecosystem that are influenced by decadal climate events. Wavelet analysis results revealed crucial synchronous shifts in the connection between the pelagic ecosystems at low trophic levels in relation to the immature BET cohort. Many variables exhibited decreasing trends after 2004–2005, and we followed the Pacific Decadal Oscillation (PDO) as a bottom-up control regulator. The results indicated that low recruitment into the mature cohort occurs 3 years after a decrease in the immature cohort’s food stocks, as indicated by a 3-year lag in our results. This finding demonstrated that, by exploring the connection between low-trophic-level species and top predators at various life stages, we can better understand how climate change affects the distribution and abundance of predator fish.

scholarly journals ERSEM 15.06: a generic model for marine biogeochemistry and the ecosystem dynamics of the lower trophic levels

2016 ◽  
Vol 9 (4) ◽  
pp. 1293-1339 ◽  
Author(s):  
Momme Butenschön ◽  
James Clark ◽  
John N. Aldridge ◽  
Julian Icarus Allen ◽  
Yuri Artioli ◽  
...  
Keyword(s):  
Food Web ◽  
Current Model ◽  
Marine Ecosystem ◽  
Ecosystem Model ◽  
Essential Elements ◽  
Ecosystem Dynamics ◽  
Trophic Levels ◽  
Global Ocean ◽  
Generic Model ◽  
The North

Abstract. The European Regional Seas Ecosystem Model (ERSEM) is one of the most established ecosystem models for the lower trophic levels of the marine food web in the scientific literature. Since its original development in the early nineties it has evolved significantly from a coastal ecosystem model for the North Sea to a generic tool for ecosystem simulations from shelf seas to the global ocean. The current model release contains all essential elements for the pelagic and benthic parts of the marine ecosystem, including the microbial food web, the carbonate system, and calcification. Its distribution is accompanied by a testing framework enabling the analysis of individual parts of the model. Here we provide a detailed mathematical description of all ERSEM components along with case studies of mesocosm-type simulations, water column implementations, and a brief example of a full-scale application for the north-western European shelf. Validation against in situ data demonstrates the capability of the model to represent the marine ecosystem in contrasting environments.

Effects of Climate Change and Fisheries on the Marine Ecosystem of the Baltic Sea

2019 ◽  
Author(s):  
Christian Möllmann
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Regime Shift ◽  
Sea Water ◽  
Marine Ecosystem ◽  
Trophic Levels ◽  
Ecosystem Structure ◽  
The Baltic Sea ◽  
Recruitment Failure ◽  
The Baltic

Climate change and fisheries have significantly changed the Baltic Sea ecosystem, with the demise of Eastern Baltic cod (Gadus morhua callarias) being the signature development. Cod in the Central Baltic Sea collapsed in the late 1980s as a result of low reproductive success and overfishing. Low recruitment and hence small year-classes were not able to compensate for fishing pressures far above sustainable levels. Recruitment failure can be mainly related to the absence of North Sea water inflows to the Central Baltic deep basins. These major Baltic inflows (MBIs) occurred regularly until the 1980s, when their frequency decreased to a decadal pattern, a development attributed to changes in atmospheric circulation patterns. MBIs are needed for ventilation of otherwise stagnating Baltic deep waters, and their absence caused reduced oxygen and salinity levels in cod-spawning habitats, limiting egg and larval survival. Climate change, on the other hand, has promoted a warmer environment richer in zooplanktonic food for larval Baltic sprat (Sprattus sprattus). Resulting large year-classes and low predation by the collapsed cod stock caused an outburst of the sprat stock that cascaded down to the zoo- and phytoplankton trophic levels. Furthermore, a large sprat population controlled cod recruitment and hence hindered a recovery of the stock by predation on cod eggs, limiting cod larval food supply. The change in ecosystem structure and function caused by the collapse of the cod stock was a major part and driver of an ecosystem regime shift in the Central Baltic Sea during the period 1988 to 1993. This reorganization of ecosystem structure involved all trophic levels from piscivorous and planktivorous fish to zoo- and phytoplankton. The observed large-scale ecosystem changes displayed the characteristics of a discontinuous regime shift, initiated by climate-induced changes in the abiotic environment and stabilized by feedback loops in the food web. Discontinuous changes such as regime shifts are characteristically difficult to reverse, and the Baltic ecosystem recently rather shows signs of increasing ecological novelty for which the failed recovery of the cod stock despite a reduction in fishing pressure is a clear symptom. Unusually widespread deficient oxygen conditions in major cod-spawning areas have altered the overall productivity of the population by negatively affecting growth and recruitment. Eutrophication as a consequence of intensive agriculture is the main driver for anoxia in the Baltic Sea amplified by the effects on continuing climate change and stabilized by self-enforcing feedbacks. Developing ecological novelty in the Baltic Sea hence requires true cross-sectoral ecosystem-based management approaches that truly integrate eutrophication combatment, species conservation, and living resources management.

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