Download Seaweeds and seagrasses

Progress report: “Survey of alien Indo-Pacific seaweeds and
seagrasses along the Israeli Mediterranean coast”
Dr. Razy Hoffman
Department of Molecular Biology & Ecology of Plants Tel Aviv University
Aims stated in the grant proposal:
1) To search collect and study alien IP seaweed and seagrass species along the IM
coastal area and update the current checklist
2) To map and revise the distribution of key and new alien species along the Israeli
shore.
3) To assess their potential effects on the local marine Flora and Fauna.
4) To upgrade the collection of the National Algal Collection by the addition of benthic
algae and seagrasses.
The following tasks were either accomplished or in Progress:
1) Nearly 20 days of algal and seagrass surveys took place at 18 sites along the
Israeli Mediterranean coast from Zikim in the south until Rosh HaNikra in the north.
These sites were checked during autumn 2013 and winter 2013-14, focusing on alien
species. The subtidal was scanned at these sites mainly in order to detect seagrass
beds of Halophila stipulacea (alien) and Cymodocea nodosa (native species).
Surveys revealed more than five new alien seaweed species to the eastern basin of
the Mediterranean as well as many new species that have never been documented
in Israel (not in the national algal lists) but some of them were reported as being
found in other countries of the Levant, Egypt or Turkey. Moreover, two of these new
alien seaweeds originated from the Atlantic and not from the Indo Pacific region
which is the main origin of alien species in the Mediterranean. As the data still need
to be published in press, I don’t provide any scientific name of the new found alien
and local species yet! One of the most interesting findings revealed during winter
surveys was the discovery of two Mediterranean seaweed species of a Genus that
has not been documented from our region yet. The fact that not even a single
seagrass bed was found yet is worrisome!
2) Algal surveys shed some light on the distribution and the spread of alien seaweed
along the Israeli Mediterranean shore. These alien were found all along our
Mediterranean coast but the biggest population concentrated in the northern shores
of Israel. Distribution map along the Israeli Mediterranean was prepared to each alien
seaweed species found so far.
3) Oppression effect of nonindigenous species on the local marine flora was mainly
observed at the range between Haifa and Rosh HaNikra where some species of alien
seaweed (including one of the newcomers) bloomed, became invasive and replaced
most of the local flora. Random sampling of the algal drift that took place during
surveys at 5 sites revealed that alien species contributed about 90% of the total
biomass in the algal drift along the northern Israeli shore! The fact that the number of
specimens of alien seaweed collected increased so dramatically indicate that it
became a major treat to the local marine flora altering the ecosystem structure and
functioning by monopolizing space and acting as ecosystem engineers!
4) The National Algal Collection at Tel-Aviv University was upgraded by the addition
of over 2500 new samples stored (dry or wet) at nearly 750 Herbarium specimens.
Some are unique since they store new species that were not reported from Israel yet.
5) A review chapter concerning and describing alien benthic algae and seagrasses in
the Mediterranean Sea and their connection to global warming was published in the
book “The Mediterranean Sea: its history and present challenges” published by the
Springer scientific publication (See PDF attached)
6) Two new manuscripts focusing on some new alien and local seaweed species
found during the surveys are in preparation.
Future Plans
1) Spring and summer surveys will take place at the same sites. We will also sample
the seaweeds and seagrasses of the subtidal and the infralittoral by the use of
Mediterranean Explorer vessel.
2) In order to confirm identifications of some of the new species molecularly, we will
purchased kits, materials and primers for DNA extraction, PCR reaction and
molecular cloning.
3) We will buy dedicated equipment and materials used to prepare the new samples
of the national algal and seagrass collection.