Keywords: seagrass, seed germination, climate change, Zostera,
estuary, thermal effects
Seagrasses provide critical ecosystem services such as carbon
sequestration, sediment stabilisation and nursery habitat for juvenile
fish. Zostera muelleri is ubiquitous within Australian and
New Z ealand estuaries however as a species is relatively
understudied. We sourced seeds from a thermally-affected east Australian
estuary and investigated if germination rates differed between ambient
and thermally affected seeds over a variety of temperatures (16°C, -
28°C) to determine how seagrass systems might react in a warming
climate. Germination for the experiment was low and totalled 5% of all
seeds however similar numbers are typical in seed germination studies.
Germination was highest at 16°C and was enhanced through the simulation
of a 48-hour freshwater pulse. Thermally affected sites germinated
faster and had greater mean maximum germination when compared to control
sites regardless of experimental temperature. These findings indicate
that Zostera muelleri in this system may be exhibiting
transgenerational plasticity due to the thermal stress the parent
experiences. This result provides an alternate viewpoint to current
literature by suggesting that unknown transgenerational effects may
provide Z. muelleri with greater germination plasticity
against temperatures expected under predicted climate change scenarios
than previously expected.