Iron defecation by sperm whales stimulates carbon export in the Southern Ocean

Lavery, Trish J.; Roudnew, Ben; Gill, Peter C.; Seymour, Justin R.; Seuront, Laurent; Johnson, Genevieve; Mitchell, James G.; Smetacek, Victor

doi:10.1098/rspb.2010.0863

Cited by 123 publications

(132 citation statements)

References 32 publications

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“…The restoration of whale populations could increase productivity by transferring nutrients to oligotrophic areas and enhancing Fe and N at the ocean surface. These processes can regulate atmospheric CO 2 levels through the stimulation of new primary production and consequent export of carbon to the deep ocean (16,44).…”

Section: Percent Of Originalmentioning

confidence: 99%

Global nutrient transport in a world of giants

Doughty

Roman

Faurby

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

336

333

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The past was a world of giants, with abundant whales in the sea and large animals roaming the land. However, that world came to an end following massive late-Quaternary megafauna extinctions on land and widespread population reductions in great whale populations over the past few centuries. These losses are likely to have had important consequences for broad-scale nutrient cycling, because recent literature suggests that large animals disproportionately drive nutrient movement. We estimate that the capacity of animals to move nutrients away from concentration patches has decreased to about 8% of the preextinction value on land and about 5% of historic values in oceans. For phosphorus (P), a key nutrient, upward movement in the ocean by marine mammals is about 23% of its former capacity (previously about 340 million kg of P per year). Movements by seabirds and anadromous fish provide important transfer of nutrients from the sea to land, totalling ∼150 million kg of P per year globally in the past, a transfer that has declined to less than 4% of this value as a result of the decimation of seabird colonies and anadromous fish populations. We propose that in the past, marine mammals, seabirds, anadromous fish, and terrestrial animals likely formed an interlinked system recycling nutrients from the ocean depths to the continental interiors, with marine mammals moving nutrients from the deep sea to surface waters, seabirds and anadromous fish moving nutrients from the ocean to land, and large animals moving nutrients away from hotspots into the continental interior. There were giants in the world in those days.Genesis 6:4, King James version T he past was a world of giants, with abundant whales in the oceans and terrestrial ecosystems teeming with large animals. However, most ecosystems lost their large animals, with around 150 mammal megafaunal (here, defined as ≥44 kg of body mass) species going extinct in the late Pleistocene and early Holocene (1, 2). These extinctions and range declines continued up through historical times and, in many cases, into the present (3). No global extinctions are known for any marine whales, but whale densities might have declined between 66% and 99% (4-6). Some of the largest species have experienced severe declines; for example, in the Southern Hemisphere, blue whales (Balaenoptera musculus) have been reduced to 1% of their historical numbers as a result of commercial whaling (4). Much effort has been devoted to determining the cause of the extinctions and declines, with less effort focusing on the ecological impacts of the extinctions. Here, we focus on the ecological impacts, with a specific focus on how nutrient dynamics may have changed on land following the lateQuaternary megafauna extinctions, and in the sea and air following historical hunting pressures.Most biogeochemists studying nutrient cycling focus on in situ production, such as weathering or biological nitrogen (N) fixation, largely ignoring lateral fluxes by animals because they are considered of secondary importance (...

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Section: Percent Of Originalmentioning

confidence: 99%

Global nutrient transport in a world of giants

Doughty

Roman

Faurby

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

336

333

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“…On the other hand, migrating animals can also reintroduce nutrients and carbon from depth back up into the photic zone. Cladocerans, for instance, have been found to increase phosphorus concentrations in the epilimnion after feeding on algae in the hypolimnion (Haupt et al 2010); nocturnally ascending mysids release trace metals into the water column after feeding on lake sediments during the day (Song and Breslin 1999); and sperm whales defecate iron-rich feces into the photic zone when returning from deep-sea foraging (Lavery et al 2010).…”

mentioning

confidence: 99%

Seabed foraging by Antarctic krill: Implications for stock assessment, bentho‐pelagic coupling, and the vertical transfer of iron

Schmidt

Atkinson

Steigenberger

et al. 2011

Limnology & Oceanography

177

175

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A compilation of more than 30 studies shows that adult Antarctic krill (Euphausia superba) may frequent benthic habitats year-round, in shelf as well as oceanic waters and throughout their circumpolar range. Net and acoustic data from the Scotia Sea show that in summer 2-20% of the population reside at depths between 200 and 2000 m, and that large aggregations can form above the seabed. Local differences in the vertical distribution of krill indicate that reduced feeding success in surface waters, either due to predator encounter or food shortage, might initiate such deep migrations and results in benthic feeding. Fatty acid and microscopic analyses of stomach content confirm two different foraging habitats for Antarctic krill: the upper ocean, where fresh phytoplankton is the main food source, and deeper water or the seabed, where detritus and copepods are consumed. Krill caught in upper waters retain signals of benthic feeding, suggesting frequent and dynamic exchange between surface and seabed. Krill contained up to 260 nmol iron per stomach when returning from seabed feeding. About 5% of this iron is labile, i.e., potentially available to phytoplankton. Due to their large biomass, frequent benthic feeding, and acidic digestion of particulate iron, krill might facilitate an input of new iron to Southern Ocean surface waters. Deep migrations and foraging at the seabed are significant parts of krill ecology, and the vertical fluxes involved in this behavior are important for the coupling of benthic and pelagic food webs and their elemental repositories.

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“…Goldstein et al (2009) collected sea lion (Zalophus californianus) faeces for domoic acid analysis, and Roman and McCarthy (2010) investigated humpback whale (Megaptera novaeangliae) fecal plumes to test the whale pump hypothesis which refers to the recycling process of nitrogen in the marine environment. A similar approach was done by Lavery et al (2010) for sperm whales (Physeter macrocephalus) that stimulate carbon export to the atmosphere by producing iron-rich faeces. Marine mammal faeces were also investigated by Marcus et al (1998) for elucidating harbour and grey seal (Phoca vitulina and Halichoerus grypus) diets, for revealing the gut microbial diversity of polar bears (Ursus maritimus; Glad et al 2010), and for investigating nutritional stress in killer whales (Orcinus orca; Ayres et al 2012).…”

Section: Overview Of In Vivo In Vitro and In Silico Research Directimentioning

confidence: 99%

Toxicology of Marine Mammals: New Developments and Opportunities

Weijs

Zaccaroni

2015

Arch Environ Contam Toxicol

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It is widely recognized that marine mammals are exposed to a wide variety of pollutants, with a weight of evidence indicating impacts on their health. Since hundreds of new chemicals enter the global market every year, the methods, approaches and technologies used to characterize pollution levels or impacts are also in a constant state of flux. However, legal and ethical constraints often limit the type and extent of toxicological research being carried out in marine mammals. Nevertheless, new and emerging in vivo, in vitro as well as in silico research opportunities abound in the field of marine mammal toxicology. In the application of findings to population-, species-, or habitatrelated risk assessments, the identification of causal relationships which inform source apportionment is important. This, in turn, is informed by a comprehensive understanding of contaminant classes, profiles and fate over space and time. Such considerations figure prominently in the design and interpretation of marine mammal (eco)-toxicology research. This mini-review attempts to follow the evolution behind marine mammal toxicology until now, highlight some of the research that has been done and suggest opportunities for future research. This Special Issue will showcase new developments in marine mammal toxicology, approaches for exposure-effect research in risk assessment as well as future opportunities.

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Iron defecation by sperm whales stimulates carbon export in the Southern Ocean

Cited by 123 publications

References 32 publications

Global nutrient transport in a world of giants

Global nutrient transport in a world of giants

Seabed foraging by Antarctic krill: Implications for stock assessment, bentho‐pelagic coupling, and the vertical transfer of iron

Toxicology of Marine Mammals: New Developments and Opportunities

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