Top predators rely on carbon derived from giant kelp Macrocystis pyrifera

Kelp forests are an important ecological component of temperate coastal systems that are sensitive to anthropogenic disturbance and are in decline in many locations globally. In the northeastern Pacific Ocean off the coast of Washington, USA, bull kelp Nereocystis luetkeana forests are seasonally used by juvenile salmonids and forage fishes; however, details on ecosystem functional linkages for forage fishes and salmonids are not well quantified. Using a zooplankton drop net and snorkel surveys for fishes, we sampled two bull kelp forests across multiple years. Our goal was to quantify differences in the communities of zooplankton, juvenile salmonids (Chinook Salmon Oncorhynchus tshawytscha and Coho Salmon O. kisutch), and forage fishes (Pacific Herring Clupea pallasii, Surf Smelt Hypomesus pretiosus, and Pacific Sand Lance Ammodytes hexapterus) between kelp forests and adjacent nonkelp (open‐water) habitats. We tested the hypothesis that zooplankton common in the diets of surface‐oriented forage fishes and juvenile salmonids would be more abundant in kelp than in open water. At the overall assemblage level of organization, kelp and open‐water habitats had similarly abundant and diverse zooplankton communities. However, decapods and phytal‐associated harpacticoid copepods within this assemblage (i.e., groups that are an important component of fish diets) were significantly more abundant in kelp forests than in open‐water habitat. Greater presence and abundance of zooplankton, juvenile salmonids, and forage fishes in kelp forests compared to adjacent open‐water habitats suggest that kelp forests are important for culturally and economically valuable forage fishes and salmonids and warrant further study to define and conserve their ecosystem function.

show abstract

“…Similar prey–phytal relationships have been found for other species of fish in kelp beds (Koenigs et al. ).…”

Section: Discussionsupporting

confidence: 83%

Kelp Forest Zooplankton, Forage Fishes, and Juvenile Salmonids of the Northeast Pacific Nearshore

Shaffer¹,

Munsch²,

Cordell

2020

Mar Coast Fish

View full text Add to dashboard Cite

show abstract

“…For example, using both bulk tissue δ 13 C and δ 15 N and gut content analysis, Koenigs et al. () found a positive but noisy relationship between the contribution of kelp‐derived energy and the trophic position of fish species in a California kelp forest. Here, we suspect that the greater degree of kelp‐derived EAA in the two upper trophic‐level species is related to their degree of motility.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, the subsidies from each source may be influenced by the trophic position or functional group of a species (Koenigs et al. , von Biela et al. ).…”

Section: Discussionmentioning

confidence: 99%

The importance of kelp to an intertidal ecosystem varies by trophic level: insights from amino acid δ¹³C analysis

2018

View full text Add to dashboard Cite

A fundamental question in ecology is understanding how energy and nutrients move through and between food webs, and which sources of production support consumers. In marine ecosystems, these basic questions have been challenging to answer given the limitation of observational methods. Stable isotope analysis of essential amino acids (EAA δ13C) has great potential as a tool to quantify energy and nutrient flow through marine food webs; however, it has been primarily utilized at large spatial scales. Here, we used EAA δ13C analysis to test for connectivity between adjacent subtidal and intertidal components of a nearshore ecosystem in south central Alaska. We measured δ13C of six EAA from four marine producer groups: subtidal kelp (Laminaria sp.), offshore particulate organic matter (POM), and intertidal red (Neorhodomela sp.) and green (Ulva sp.) algae. In addition, we sampled four intertidal invertebrate consumer species spanning a range of trophic/functional groups: Mytilus sp., Strongylocentrotus droebachiensis, Nucella sp., and Pycnopodia helianthoides. Using canonical analysis of principal coordinates (CAP) and isotope mixing models (MixSIAR), we tested for differences among producer EAA δ13C fingerprints and quantified the contribution of producer EAA to consumers. We compared these results to previously published EAA δ13C data on marine producers to examine the generality of this technique. We found the EAA δ13C fingerprints of subtidal kelps (Laminaria), Ulva, and Neorhodomela were highly distinct from one another. Further, our measured EAA δ13C patterns for kelp and red algae matched those previously reported from other localities, suggesting unique and universal EAA δ13C signatures for these groups. However, CAP could not distinguish between microalgae (POM) and Ulva, possibly due to similar biochemical pathways for the synthesis of EAA. Using these producer fingerprints, we found upper trophic‐level invertebrate consumers, Nucella and Pycnopodia, derived more than 60% of their essential amino acids from subtidal kelps. In contrast, the sampled primary consumers in the system, Mytilus and Strongylocentrotus, relied more heavily on Ulva and/or offshore POM. Our results provide evidence for connectivity between two adjacent nearshore ecosystems and exemplify EAA δ13C as a powerful new tool in tracing energy and nutrient flow within and among marine food webs.

show abstract

“…, Koenigs et al. ). The most comprehensive efforts estimate that the production of giant kelp ( Macrocystis pyrifera ), the predominant macroalgae in central and southern California kelp forests, is approximately 5.5 kg·m −2 ·yr −1 (Rassweiler et al.…”

Section: Introductionmentioning

confidence: 99%

Coastal marine ecosystem connectivity: pelagic ocean to kelp forest subsidies

Zuercher

Galloway

2019

Ecosphere

View full text Add to dashboard Cite

The movement of trophic resources between and among ecosystems, referred to as cross‐ecosystem subsidies, is a common phenomenon. In the marine environment, both adjacent and distant ecosystems are connected by oceanographic forces that transport nutrients, organisms, and other materials. Kelp forest ecosystems are one example of an open marine system that both exports and receives trophic subsidies. Though rocky reefs are rich in kelp‐based energy produced internally, kelp forest organisms also rely on phytoplankton, and the influx of holoplankton and meroplankton from adjacent open ocean habitats. In this paper, we seek to clarify the identity of holoplanktonic and meroplanktonic subsidies, quantify their energetic and nutrient contributions to the kelp forest, and further explore the impacts of these subsidies for individual consumers and for kelp forest communities. We reviewed six individual subsidy organisms that are commonly advected to kelp forests on the West coast of North America, and show that these organisms from the pelagic ocean represent important resource pulses for kelp forest consumers. In addition, we summarize the characteristics of subsidies, consumers, and recipient ecosystems that provide insight into the dynamics of subsidy influx and impacts to recipient systems. Finally, we provide suggestions as scientists move forward with efforts to quantify the impacts of cross‐ecosystem subsidies. Trophic subsidies are a major force shaping both marine and terrestrial communities and ecosystems. Quantitative information about these subsidies and their impacts on food webs will not only improve our understanding of these ecosystems, but also improve food web models, and predictions of ecosystem response to change.

show abstract

Top predators rely on carbon derived from giant kelp Macrocystis pyrifera

Cited by 41 publications

References 48 publications

Kelp Forest Zooplankton, Forage Fishes, and Juvenile Salmonids of the Northeast Pacific Nearshore

Kelp Forest Zooplankton, Forage Fishes, and Juvenile Salmonids of the Northeast Pacific Nearshore

The importance of kelp to an intertidal ecosystem varies by trophic level: insights from amino acid δ¹³C analysis

Coastal marine ecosystem connectivity: pelagic ocean to kelp forest subsidies

Contact Info

Product

Resources

About

Top predators rely on carbon derived from giant kelp Macrocystis pyrifera

Cited by 41 publications

References 48 publications

Kelp Forest Zooplankton, Forage Fishes, and Juvenile Salmonids of the Northeast Pacific Nearshore

Kelp Forest Zooplankton, Forage Fishes, and Juvenile Salmonids of the Northeast Pacific Nearshore

The importance of kelp to an intertidal ecosystem varies by trophic level: insights from amino acid δ13C analysis

Coastal marine ecosystem connectivity: pelagic ocean to kelp forest subsidies

Contact Info

Product

Resources

About

The importance of kelp to an intertidal ecosystem varies by trophic level: insights from amino acid δ¹³C analysis