Seagrass restoration will be both economically and environmentally
beneficial to Tampa Bay. In addition to improving water quality,
healthy seagrass beds benefit important fishery species such as
snook, seatrout, and shrimp.
Why Restore Seagrass Beds?
Since the 1800s, approximately 80
percent of the seagrass coverage in Tampa Bay has been lost mainly
due to human activities. Ninety percent of the seagrass loss
occurred between 1950 and 1982. Seagrasses are both economically
and environmentally important; therefore, existing seagrass beds
need to be preserved and expanded. Restoration of Tampa Bay's
seagrass beds will not only improve water quality, but will also
benefit important fishery species such as snook, seatrout, and
shrimp. Whether it is the relocation of an entire bed or the
removal of random plugs from an existing bed, the use of donor beds
is necessary for seagrass restoration at this time. Currently, we
are working on a tissue-culture technique, micropropagation, that
could provide sustainable stocks of seagrass for restoration
projects without causing extensive damage to existing seagrass
What is Micropropagation?
Micropropagation is a way to clone plants axenically (sterile).
Terminal buds collected from branches of mature plants are surface
sterilized and placed in test tubes containing a specific nutrient
medium. The different media we are experimenting with usually
contain a carbon source, vitamins, plant hormones and antibiotics.
Plantlets grown from buds of the same plant, barring mutation, will
be clones (i.e., genetic replicates) of the plant from which they
were cut. Once we are able to maintain rapidly multiplying plant
stocks in the lab, we can use them as a source for additional
micropropagation or subculturing. Subculturing involves dividing
sterile plantlets into smaller segments and growing plants from
these pieces. This is how we grow Widgeon-grass (Ruppia
maritima) in the lab, and we are in the process of developing
this technique for Shoal-grass (Halodule wrightii).
Widgeon-grass is the easiest seagrass to micropropagate; other
species, such as Shoal-grass (Halodule), Manatee-grass
(Syringodium filiforme) and Turtle-grass (Thalassia
testudinum), are increasingly difficult. We are focusing on
one species at a time.
Why Use Micropropagation?
Compared to standard nursery techniques, micropropagation has the
potential to produce more plants in less time. Fewer stock plants
are needed because an explant can supply a great amount of material
from which clonal material can be subcultured. Also, not having to
rely on seeds and other propagation methods ensures greater
uniformity in plants produced. Clones can be screened for different
attributes and used for specific applications, or genetic
variability can be assured by mixing different clonal strains in
restoration projects. Another advantage to micropropagation is the
contamination-free condition of the plants produced and the ability
to produce microbially fit stocks that resist pathogens.
Seagrass Planting Techniques
Micropropagation will be the key to establishing non-destructive
seagrass restoration and mitigation. Traditionally, seagrass has
been planted by hand. Many materials have been used as substrates
for rooting and anchoring plantlets. These include peat pellets,
peat pots, and coconut-fiber mats. Success rates with hand planting
have been variable. A new method using a boat with a planting wheel
is being developed. We are developing protocols to transfer
lab-produced seagrasses to the field for mechanical planting. This
technique will reduce damage to the plantlets during
transplantation, increase the planting rate, and cause less
disturbance to sediment structure.