Gut content, fatty acid, and stable isotope analyses reveal dietary sources of macroalgal-associated amphipods along the western Antarctic Peninsula

Aumack, Craig F.; Lowe, Alexander T.; Amsler, Charles D.; Amsler, Margaret O.; McClintock, James B.; Baker, Bill J.

doi:10.1007/s00300-016-2061-4

Cited by 29 publications

(35 citation statements)

References 65 publications

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“…The low variation within a treatment group for wild and laboratory-maintained amphipods suggests that wild G. antarctica are consuming similar diets, with high proportions of diatoms, as suggested by Aumack et al (2017). The present results suggest that diatoms do not make up the entire diet of G. antarctica, as evidenced by the consistent shift of wild amphipods to the right on the nMDS plot, and similarly correlated with the increased proportion of 20:5ω3 (Fig.…”

Section: Resultssupporting

confidence: 69%

“…Gondogeneia antarctica and most other amphipods are chemically deterred from consuming the macroalgae (Amsler et al 2014). They primarily consume diatoms, other microalgae, filamentous macroalgae and a few undefended macroalgal species, including Palmaria decipiens (Aumack et al 2017). Although unpalatable when alive, G. antarctica and other amphipods will consume the chemically defended brown algae Himantothallus grandifolius and Desmarestia anceps within a few weeks of death (Amsler et al 2014).…”

Section: Introductionmentioning

confidence: 99%

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Fatty acid trophic transfer of Antarctic algae to a sympatric amphipod consumer

et al. 2019

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The shallow benthos along the western Antarctic Peninsula supports brown macroalgal forests with dense amphipod assemblages, commonly including Gondogeneia antarctica (Amsler et al. 2014). Gondogeneia antarctica and most other amphipods are chemically deterred from consuming the macroalgae (Amsler et al. 2014). They primarily consume diatoms, other microalgae, filamentous macroalgae and a few undefended macroalgal species, including Palmaria decipiens (Aumack et al. 2017). Although unpalatable when alive, G. antarctica and other amphipods will consume the chemically defended brown algae Himantothallus grandifolius and Desmarestia anceps within a few weeks of death (Amsler et al. 2014).

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Section: Resultssupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Fatty acid trophic transfer of Antarctic algae to a sympatric amphipod consumer

et al. 2019

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“…Although the vast majority of the large Antarctic macroalgae are chemically defended from the amphipods (Amsler et al 2008, 2014, Aumack et al 2010, Núñez-Pons et al 2012), the amphipods benefit from the association because the chemically defended macroalgae they live on provide associational defence from predatory fish (Zamzow et al 2010). In turn, the amphipods greatly benefit the large macroalgae by grazing down their associated epiphytic microalgae and filamentous macroalgae (Aumack et al 2011a, 2017, Amsler et al 2012, 2014). Although filamentous algae are common in high-energy areas of the upper intertidal zone where mesograzers have little access to them, they are very uncommon in the subtidal zone except growing endophytically within chemically defended macroalgae (Peters 2003, Amsler et al 2009).…”

Section: Introductionmentioning

confidence: 99%

“…In a mesocosm aquarium experiment using tanks with and without natural densities of amphipods, in tanks lacking amphipods filamentous endophytes were able to grow out which, along with heavy growths of diatoms, heavily fouled the surfaces of their hosts within seven weeks (Aumack et al 2011a). Correspondingly, gut content analyses of macroalgal-associated subtidal amphipods found diatoms to be the most abundant food item in most amphipod species while filamentous algae constituted between 6% and 16% of the gut contents, even though they rarely grow to sizes visible to divers (Aumack et al 2017). By dramatically reducing epiphytic microalgae and filamentous algae which otherwise would compete with the ecologically dominant macroalgae, the hugely abundant amphipods clearly play an important role in their communities.…”

Section: Introductionmentioning

confidence: 99%

Impacts of gastropods on epiphytic microalgae on the brown macroalga Himantothallus grandifolius

Amsler

Curtis

et al. 2019

Antarctic Science

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Chemically defended benthic macroalgae that dominate shallow, hard bottom communities along the western Antarctic Peninsula support very high densities of mesograzers, particularly amphipods but also small gastropods. Previous studies have demonstrated that the macroalgae and amphipods form a mutualistic relationship. The chemically defended macroalgae provide the amphipods with a refuge from predation while the macroalgae benefit from the amphipods greatly reducing surface fouling by smaller algae. One of the three most important macroalgae in terms of overstory cover, Himantothallus grandifolius, forms huge blades that can carpet the benthos. Field observations suggest that gastropods may be higher in relative abundance in proportion to amphipods on H. grandifolius than on other overstory macroalgae. The present study documents the finding that natural abundances of gastropods on H. grandifolius maintained in mesocosms reduce fouling by microscopic algae, primarily diatoms. However, amphipods are probably also important in keeping the macroalga clean of diatoms in nature. In a smaller scale experiment, three gastropod species were differentially effective at reducing diatom coverage on H. grandifolius. The hypothesis that gastropods benefit from associating with H. grandifolius in potentially gaining a refuge from sea-star predation was also tested but not supported by the experimental results.

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“…As phytoplankton biomass is generally low in Potter Cove (Schloss and Ferreyra ), both macroalgae and microphytobenthos have been proposed to constitute an important food supply for benthic organisms (Iken ; Quartino and Boraso de Zaixso ; Hoffmann et al, ). As most brown macroalgae produce secondary metabolites used as a chemical defense against herbivory (Amsler et al ), direct herbivory by amphipods on especially brown macroalgae is considered unlikely (Aumack et al ). However, some macrofauna, such as gastropods, annelids, crustaceans, echinoderms, and fish seem to graze on macroalgae themselves (McClintock ; Iken et al , , ; Iken ).…”

mentioning

confidence: 99%

Degradation of macroalgal detritus in shallow coastal Antarctic sediments

Braeckman

Pasotti

Vázquez

et al. 2019

Limnology & Oceanography

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Glaciers along the western Antarctic Peninsula are retreating at unprecedented rates, opening up sublittoral rocky substrate for colonization by marine organisms such as macroalgae. When macroalgae are physically detached due to storms or erosion, their fragments can accumulate in seabed hollows, where they can be grazed upon by herbivores or be degraded microbially or be sequestered. To understand the fate of the increasing amount of macroalgal detritus in Antarctic shallow subtidal sediments, a mesocosm experiment was conducted to track 13C‐ and 15N‐labeled macroalgal detritus into the benthic bacterial, meiofaunal, and macrofaunal biomass and respiration of sediments from Potter Cove (King George Island). We compared the degradation pathways of two macroalgae species: one considered palatable for herbivores (the red algae Palmaria decipiens) and other considered nonpalatable for herbivores (the brown algae Desmarestia anceps). The carbon from Palmaria was recycled at a higher rate than that of Desmarestia, with herbivores such as amphipods playing a stronger role in the early degradation process of the Palmaria fragments and the microbial community taking over at a later stage. In contrast, Desmarestia was more buried in the subsurface sediments, stimulating subsurface bacterial degradation. Macrofauna probably relied indirectly on Desmarestia carbon, recycled by bacteria and microphytobenthos. The efficient cycling of the nutrients and carbon from the macroalgae supports a positive feedback loop among bacteria, microphytobenthos, and meiofaunal and macrofaunal grazers, resulting in longer term retention of macroalgal nutrients in the sediment, hence creating a food bank for the benthos.

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Gut content, fatty acid, and stable isotope analyses reveal dietary sources of macroalgal-associated amphipods along the western Antarctic Peninsula

Cited by 29 publications

References 65 publications

Fatty acid trophic transfer of Antarctic algae to a sympatric amphipod consumer

Fatty acid trophic transfer of Antarctic algae to a sympatric amphipod consumer

Impacts of gastropods on epiphytic microalgae on the brown macroalga Himantothallus grandifolius

Degradation of macroalgal detritus in shallow coastal Antarctic sediments

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