Data from: Seasonal patterns in B-vitamins and cobalamin co-limitation in the Northwest Atlantic

B-vitamins are important co-enzymes that have long been hypothesized to
play key roles in marine ecosystems. However, environmental measurements
remain scarce, which limits our understanding of their potential impact.
Here, we present mass spectrometry-based measurements of B-vitamins (B1,
B2, B3, B5, B6, B12) and related vitamers along a transect in the
Northwest Atlantic Ocean, in both particulate phase and dissolved in
seawater, seasonally over 5 years. We then couple these data with targeted
investigations of the impact of B12 (cobalamin) on phytoplankton growth.
We show that these metabolites are present at femto to pico-molar
concentrations and demonstrate that season explains most variance in
particulate phase B-vitamins but not dissolved, offering further evidence
that metabolite inventories in these two phases are often decoupled. We
find positive correlations between particulate organic carbon with
particulate B1 and B3, and between chlorophyll a and particulate B2 and
DMB in fall but not spring, indicating unique seasonal drivers of vitamin
inventories. Of all measured vitamins, only cobalamin was enriched in the
particulate over dissolved phase, predominantly in spring. We documented
nitrogen and cobalamin co-limitation of phytoplankton growth during spring
bloom decline, when dissolved cobalamin is seemingly drawn down, but not
during fall, when dissolved cobalamin concentrations remain elevated.
These seasonal differences may be underpinned by the increased importance
of cobalamin remodeling and recycling during the fall.  This
study provides insights into the absolute concentrations, stoichiometry,
and variability of B-vitamins in the ocean and offers evidence that
cobalamin exerts seasonally-varying controls on Northwest Atlantic marine
ecosystems.