Model
Digital Document
Publisher
Florida Atlantic University
Description
Nitrogen (N) and phosphorus (P) senescent leaf retention, as a measure of
resorption, and the subsequent decay of senescent leaves, roots and rhizomes were
examined for the dominant tropical seagrass species, Thalassia testudinum, across a
nutrient gradient in Florida Bay. Leaf nutrient loss while still attached to the short
shoot, from both resorption and decay, was highest at the nutrient-rich (88% P; 51%
N) compared to nutrient-poor site ( 49% P; 25% N). High nutrient loss rates by
attached leaves (0.37-2.5 mg P and 6.5-34 mg N m^-2 d^-1) represented significant
recycling (46-87% P and 17-48% N) oftotal estimated external nutrient loads to the
bay. In contrast, senescent leaf, rhizome and root nutrient loss rates were > 1 00-fold
lower than intact leaves. In tropical /subtropical estuaries dominated by T testudinum,
seagrasses may be acting as nutrient pumps, translocating high porewater nutrients to
the overlying waters and promoting phytoplankton blooms in the bay.
resorption, and the subsequent decay of senescent leaves, roots and rhizomes were
examined for the dominant tropical seagrass species, Thalassia testudinum, across a
nutrient gradient in Florida Bay. Leaf nutrient loss while still attached to the short
shoot, from both resorption and decay, was highest at the nutrient-rich (88% P; 51%
N) compared to nutrient-poor site ( 49% P; 25% N). High nutrient loss rates by
attached leaves (0.37-2.5 mg P and 6.5-34 mg N m^-2 d^-1) represented significant
recycling (46-87% P and 17-48% N) oftotal estimated external nutrient loads to the
bay. In contrast, senescent leaf, rhizome and root nutrient loss rates were > 1 00-fold
lower than intact leaves. In tropical /subtropical estuaries dominated by T testudinum,
seagrasses may be acting as nutrient pumps, translocating high porewater nutrients to
the overlying waters and promoting phytoplankton blooms in the bay.
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