TY - JOUR
T1 - A year in the life of the Eastern Mediterranean
T2 - Monthly dynamics of phytoplankton and bacterioplankton in an ultra-oligotrophic sea
AU - Reich, Tom
AU - Ben-Ezra, Tal
AU - Belkin, Natalya
AU - Tsemel, Anat
AU - Aharonovich, Dikla
AU - Roth-Rosenberg, Dalit
AU - Givati, Shira
AU - Bialik, M.
AU - Herut, Barak
AU - Berman-Frank, Ilana
AU - Frada, Miguel
AU - Krom, Michael D.
AU - Lehahn, Yoav
AU - Rahav, Eyal
AU - Sher, Daniel
N1 - Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/4
Y1 - 2022/4
N2 - The Eastern Mediterranean Sea (EMS) is a poorly studied ultra-oligotrophic marine environment, dominated by small-size phyto- and bacterioplankton. Here, we describe the dynamics of a single annual cycle (2018–19) of phyto- and bacterioplankton (abundances, pigments and productivity) in relation to the physical and chemical conditions in the photic water column at an offshore EMS site (Station THEMO-2, ∼1,500 m depth, 50 km offshore). We show that phytoplankton biomass (as chlorophyll a), primary and bacterial productivity differed between the mixed winter (January–April) and the thermally stratified (May–December) periods. Prochlorococcus and Synechococcus numerically dominated the picophytoplankton populations, with each clade revealing different temporal and depth changes indicative to them, while pico-eukaryotes (primarily haptophytes) were less abundant, yet likely contributed significant biomass. Estimated primary productivity (∼32 gC m−2 y−1) was lower compared with other well-studied oligotrophic locations, including the north Atlantic and Pacific (BATS and HOT observatories), the western Mediterranean (DYFAMED observatory) and the Red Sea, and was on-par with the ultra-oligotrophic South Pacific Gyre. In contrast, integrated bacterial production (∼11 gC m−2 y−1) was similar to other oligotrophic locations. Phytoplankton seasonal dynamics were similar to those at BATS and the Red Sea, suggesting an observable effect of winter mixing in this ultra-oligotrophic location. These results highlight the ultra-oligotrophic conditions in the EMS and provide, for the first time in this region, a full-year baseline and context to ocean observatories in the region.
AB - The Eastern Mediterranean Sea (EMS) is a poorly studied ultra-oligotrophic marine environment, dominated by small-size phyto- and bacterioplankton. Here, we describe the dynamics of a single annual cycle (2018–19) of phyto- and bacterioplankton (abundances, pigments and productivity) in relation to the physical and chemical conditions in the photic water column at an offshore EMS site (Station THEMO-2, ∼1,500 m depth, 50 km offshore). We show that phytoplankton biomass (as chlorophyll a), primary and bacterial productivity differed between the mixed winter (January–April) and the thermally stratified (May–December) periods. Prochlorococcus and Synechococcus numerically dominated the picophytoplankton populations, with each clade revealing different temporal and depth changes indicative to them, while pico-eukaryotes (primarily haptophytes) were less abundant, yet likely contributed significant biomass. Estimated primary productivity (∼32 gC m−2 y−1) was lower compared with other well-studied oligotrophic locations, including the north Atlantic and Pacific (BATS and HOT observatories), the western Mediterranean (DYFAMED observatory) and the Red Sea, and was on-par with the ultra-oligotrophic South Pacific Gyre. In contrast, integrated bacterial production (∼11 gC m−2 y−1) was similar to other oligotrophic locations. Phytoplankton seasonal dynamics were similar to those at BATS and the Red Sea, suggesting an observable effect of winter mixing in this ultra-oligotrophic location. These results highlight the ultra-oligotrophic conditions in the EMS and provide, for the first time in this region, a full-year baseline and context to ocean observatories in the region.
KW - Bacterial productivity
KW - Eastern mediterranean
KW - Levantine basin
KW - Phytoplankton
KW - Pico-eukaryotes
KW - Primary productivity
KW - Prochlorococcus
KW - Seasonal dynamics
KW - Synechococcus
UR - http://www.scopus.com/inward/record.url?scp=85124981884&partnerID=8YFLogxK
U2 - 10.1016/j.dsr.2022.103720
DO - 10.1016/j.dsr.2022.103720
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AN - SCOPUS:85124981884
SN - 0967-0637
VL - 182
JO - Deep-Sea Research Part I: Oceanographic Research Papers
JF - Deep-Sea Research Part I: Oceanographic Research Papers
M1 - 103720
ER -