FN Archimer Export Format
PT J
TI The Delayed Island Mass Effect: how islands can remotely trigger blooms in the oligotrophic ocean
BT 
AF Messié, M.
   Petrenko, A.
   Doglioli, A.M.
   Aldebert, C.
   Martinez, Elodie
   Koenig, G.
   Bonnet, S.
   Moutin, T.
AS 1:1,2;2:1;3:1;4:1;5:3;6:1;7:1;8:1;
FF 1:;2:;3:;4:;5:;6:;7:;8:;
C1 Aix Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO), Unité Mixte 110 Marseille ,France
   Monterey Bay Aquarium Research Institute Moss Landing CA, USA
   University of Brest, Ifremer, CNRS, IRD, Laboratoire d'Océanographie Physique et Spatiale (LOPS), IUEM, Brest ,France
C2 UNIV AIX MARSEILLE, FRANCE
   MONTEREY BAY AQUARIUM RES INST, USA
   IRD, FRANCE
UM LOPS
IN WOS Cotutelle UMR
   copubli-france
   copubli-univ-france
   copubli-int-hors-europe
IF 4.72
TC 18
UR https://archimer.ifremer.fr/doc/00600/71162/69489.pdf
LA English
DT Article
CR OUTPACE
BO L'Atalante
DE ;island mass effect;Lagrangian analysis;nitrogen fixation;nutrient supply;oligotrophic ocean;phytoplankton bloom
AB In oligotrophic gyres of the tropical ocean, islands can enhance phytoplankton biomass and create hotspots of productivity and biodiversity. This “Island Mass Effect” (IME) is typically identified by increased chlorophyll concentrations next to an island. Here we use a simple plankton model in a Lagrangian framework to represent an unexplained open ocean bloom, demonstrating how islands could have triggered it remotely. This new type of IME, termed “delayed IME”, occurs when nitrate is limiting, N:P ratios are low, and excess phosphate and iron remain in water masses after an initial bloom associated to a “classical” IME. Nitrogen fixers then slowly utilize leftover phosphate and iron while water masses get advected away, resulting in a bloom decoupled in time (several weeks) and space (hundreds of km) from island‐driven nutrient supply. This study suggests that the fertilizing effect of islands on phytoplankton may have been largely underestimated. Plain language summary In the poor and nutrient‐depleted waters of the tropical Pacific, islands act as sources of nutrients fertilizing nearby waters. These nutrients are consumed by microscopic photosynthesizing algae, the phytoplankton. The resulting phytoplankton enrichments (blooms) in turn support productive ecosystems. This phenomenon, termed the “island mass effect”, has been known for sixty years and is classically defined by increased chlorophyll (representing phytoplankton biomass) next to an island. Blooms also occur in the open ocean and are usually attributed to vertical processes such as mixing or uplifting that locally supply nutrients from subsurface reservoirs. In this paper, we demonstrate that a different type of island mass effect exists, where the phytoplankton response is delayed because they grow very slowly. These blooms are supported by the nitrogen fixer Trichodesmium. Since phytoplankton get carried away from islands by oceanic currents while they grow, this can lead to a bloom located hundreds of km away with no apparent connection to the islands. Nutrient inputs by islands followed by advection can thus trigger remote blooms in the open ocean. Our study suggests that the fertilizing effect of islands may currently be largely underestimated, particularly in the warm waters of the tropical Pacific where Trichodesmimum is common. 
PY 2020
PD JAN
SO Geophysical Research Letters
SN 0094-8276
PU American Geophysical Union (AGU)
VL 47
IS 2
UT 000517154600020
DI 10.1029/2019GL085282
ID 71162
ER

EF