Table 1. Summary of studies examining the effects of seabird guano on the isotopic composition (δ15N) of plants and soils.
| Location | Bird Species | Guano δ15N (‰, AIR) | Plant δ15N (‰, AIR) | Plant δ15N (‰, AIR) | Reference | ||
| Bird | Non-bird | Bird | Non-bird | ||||
| California | Mixed | – | 36.4±2.7 | 5.3±0.9 | 33.6±2.0 | 7.2±1.2 | [13] |
| California | Mixed | – | 24.3 to 24.5 | 6.8 to 7.8 | – | – | [173] |
| Falkland Islands and Antarctica | Mixed | 10.9±1.9 | −1.8 to 15.8 | −7.9 to 7.6 | 14.0±0.3 | 0.0 to 9.7 | [174] |
| Antarctica | Snow petrel | – | −3.1 to 25.8 | −17.6 to −0.5 | 13.1 to 25.9 | −13.4 to −1.0 | [175] |
| Australia | Gentoo penguin | 14.6 | 7.2 to 18.8 | −9.8 to −0.7 | – | – | [176] |
| North Africa | Various gulls | – | 9.8 to 17.4 | – | 10.5 to 13.4 | 16.8 to 20.8 | [51] |
| New Zealand | Westland petrel | – | – | – | 14.1±0.3 | – | [177] |
| New Zealand | Mixed | – | −3.9 to 9.1 | – | – | – | [178] |
| New Zealand | Sooty shearwater | 7.7 | 14.2±3.1 | −6.1±1.7 | – | – | [179] |
| Japan | Great cormorant | – | 16.4 to 16.9 | −2.5±0.6 | 10.6 to 16.0 | 0.4±0.3 | [180] |
| Japan | Great cormorant | 13.2±1.3 | 10.0 to 14.7 | −2.3 to 6.8 | – | – | [181] |
| Sweden | Great cormorant | – | 13.6±1.7 | 1.7 | – | – | [182] |
| New Zealand | Mixed | – | 4.6 to 6.7 | 14.4 to 15.9 | 10.2±1.0 | 16.2±0.3 | [183] |
| Fiji | Mixed | 39.1 to 50.1a | 13.6 to 36.7 | −1.3 to 0.8 | 15.1 to 31.6a | −4.1 to −1.3b | [184] |
| Fiji | Mixed | 14.9 to 23.3b | – | – | 13.5 to 33.0b | – | [184] |
| Japan | Black-tailed gull | 10.2 to 10.5 | 3.9 to 14.6 | −4.1 to −2.1 | 10.1 to 43.3a | −4.3 to −2.9b | [185] |
| Japan | Black-tailed gull | – | – | – | −0.2 to 33.7b | – | [185] |
| Japan | Black-tailed gull | 9.1 to 12.8 | – | – | 18.5 to 44.1a | – | [53] |
| Japan | Black-tailed gull | – | – | – | −4.1 to 42.2b | – | [53] |
| Japan and Antarctica | Penguin and gull | 8.0 to 9.4 | 13.6 to 38.1 | – | – | – | [186] |
| Antarctica | Penguin | 7.4 | – | – | 32.1 | – | [75] |
| Japan | Mixed | – | – | – | 9.1 to 37.9 | −4.6 to 8.6 | [54] |
| New Zealand | Rockhopper penguin | 7.0±0.4 | – | – | 23.8±3.3 | −0.5±0.2 | [187] |
| Australia | Mixed | 9.9 | 9.5±2.2 | 7.0±2.6 | – | – | [55] |
| California | Mixed | – | 27.2 to 27.3 | 8.3 to 9.5 | 28.3±5.4 | – | [188] |
| Pribilof Islands | Mixed | 12.5 | 22.0 | 11.3 | – | – | [162] |
| California | Mixed | – | – | – | 35.6±2.6 | 7.5±0.3 | [56] |
| Pacific (Palmyra Atoll) | Mixed | 13.9 | 14.0±1.4 | 9.3±0.9 | 16.2±0.3 | 11.0±0.7 | [189] |
| Antarctica | Penguin | 20.9±4.2 | – | – | 10.4±3.1 | – | [190] |
a
NH4 +.
b
NO3 −.