Widgeon grass grass (Ruppia

mari ma Ruppiamari ma)

Widgeon grass is a species that has a wide geographic c area of f distribu on n and it thrives in shallow coastal lagoons, estuaries and bays in tropical and subtropical regions. Although it is generally found in brackish waters or areas with low salinity, it is very tolerant of dras c changes in salinity. Some botanists don’t consider it a seagrass, but rather a freshwater plant that tolerates salt water (Den Hartog, 1970).

Widgeon grass leaves (Figure 19) are very slender (1 mm; or 0.04 inch) and grow to about 10 cm (approx. 4 inches) long. From the main stem, several branches sprout and can grow up to 0.5 m (approx. 20 inches) long. Its anchoring system consists in fine rhizomes (or horizontal stems) and roots. The flowers are very small and usually measure between 3-5 mm (0.12-0.20 inches) and grow in pairs. Pollina on can occur either above or below the water. The fruits are dark, pear-shaped, and grow in groups. This grass is a valuable food source for migratory aqua c birds which themselves aid in seed dispersion, spreading the grass across other areas. Widgeon grass can be propagated through seeds, rhizomes or plant fragments.

Anthropogenic:This refers to the effects, processes or materials that result from human ac vi es.

Hydrophilic pollina on: Pollina on that takes place in the water.

Main threats to seagrasses in Puerto Rico

Natural

1. Storms and hurricanes - The surges associated with storms and hurricanes can be strong enough to tear and undercut wide areas of seagrass meadows. Furthermore, the resul ng erosion from these events can cause direct physical damage to the seagrasses or indirect damage if the water turbidity increases dras cally and reduces sunlight availability, not allowing plants to perform photosynthesis.

2. Climate change - The flooding and drought cycles associated with global climate change can cause fluctua ons in water salinity and temperature. These processes can also expose the seagrasses to the air for prolonged periods of me, causing them to dry out. Sea level rise may also affect seagrass zona on.

Anthropogenic (caused by human ac vity)

1. Eutrophica on - Fer lizers and pes cides used in certain land-based ac vi es can reach the coastal zone through rainwater runoff and erosion. The runoff from residen al, agricultural or industrial sites may contain contaminants that can threaten marine ecosystems. Excessive nutrients in the water can cause algal blooms and increased turbidity, thereby reducing the available sunlight for the organisms living on the sea bo om.

2. Increased sedimenta on - Urban development and some land-based human ac vi es can cause excessive sediment discharge onto coastal areas. As a consequence, water turbidity increases and light penetra on is reduced, reducing the photosynthe c abili es of the primary producers that inhabit the sea floor.

3. Boat traffic and inadequate anchoring - Boat engine propellers can cause serious harm to seagrass meadows when used in shallow waters, scarring and fragmen ng the meadows. Indiscriminate anchoring in seagrass meadows affects these habits directly and in a nega ve manner. Use of mooring buoys is recommended in areas with seagrass meadows (whenever available).

Primary producers: Organisms that use photosynthesis to produce their own organic material (autotrophs). Primary producers are the beginning of all food chains and webs.

Rainwater runoff: Rainwater that isn’t absorbed by the soil and which streams across the surface carrying sediment and pollutants to nearby waterways.

Glossary:

Aerobic decomposi on: the breakdown of organic ma er and wastes in the presence of oxygen in order to recycle nutrients.

Angiosperms: Angiosperms are plants with flowers and seeds. Some examples of these plants are passion fruits, avocados and mangoes, among many others.

Annual plant: Plant that fulfills its life cycle during the course of a year.

Anthropogenic: The term ‘anthropogenic’ refers to the effects, processes or materials that result from human ac vi es.

Biomass: Total organic material from all the organisms living in a given area.

Brackish: Water featuring more dissolved salts than freshwater, but less salt that seawater.

Carbon dioxide: A gas present in the atmosphere. It is created through living organisms’ respira on, organic material decomposi on or carbon-containing fuel combus on. This gas is fundamental for the photosynthe c process.

Carbon sink: natural or ar ficial environment viewed in terms of its ability to absorb carbon dioxide.

Cretaceous: The Cretaceous period is a division in the geological mescale. It is the third and last period of the Mesozoic Era; it began approximately 145.5 million years ago and finished approximately 65.5 million years ago.

Detritus: Residue from organic material fragmenta on.

Diffusion: Process through which molecules flow from an area with greater concentra on to an area with lower concentra on.

Dioecious: Adjec ve describing a plant that has dis nct male and female individual organisms.

Epiphytes: This refers to any organisms that grows on different surfaces (living or not), using them as a support but not causing them any direct harm (that is to say, it is not a parasite).

Estuary zones: Coastal areas in which large bodies of freshwater (such as rivers) meet the sea. They receive dal change ac vity, but are protected from direct wave and wind ac on.

Euryhaline: Organisms that can tolerate a wide range of salt concentra on. In this case, it refers to organisms that can tolerate different saline concentra ons within the aqua c environment in which they live.

Flowers with stamen: Male flowers. Flowers that have func onal stamen, capable of producing pollen but lacking an ovary, or having an infer le ovary.

Foraminifera: Small, unicellular organisms belonging to the protozoa family. Their bodies are protected by a delicate shell or test.

Gametes: Cells par cipa ng in sexual reproduc on. They only have a single copy of each chromosome (they are haploid). In many animals, we know these cells as eggs and sperm. When they unite, they form an organism with two copies of each chromosome (diploid), like you and me.

Hydrophilic: In a broad sense, it refers to something with an affinity for water. In this case, it refers to a plant which is uniquely adapted to life underwater or in aqua c environments.

Hydrophilic pollina on: Pollina on that takes place in the water.

Hyper-saline: An environment with a higher salt concentra on that sea water.

Infra-li oral zone: Part of the coast which is permanently submerged.

Laminae: Generally fla ened structure found in algae, which resembles a plant’s leaves.

Li oral zone: Coastal zone under the influence of the shi ing des.

Macrophytes: Big plants (observable to the naked eye) that are adapted to very humid or aqua c environments such as lakes, ponds, reservoirs, estuaries, swamps, riverbanks, deltas or marine lagoons.

Monocotyledons: Group of vascular plants (phanerogams) that produce flowers (angiosperms), in which the seed embryos present a single ini al leaf (a single cotyledon). Monocotyledons include corn, most cereals, tulips and onions, among others.

Nodules: Structure separa ng rhizome segments and from which leaves and/or roots sprout.

Osmoregula on: Process through which organisms maintain an adequate balance between water concentra ons and the solutes dissolved in their bodies.

Pedicel: Slender structure suppor ng algae, similar to a plant stem.

Peduncle: Branch joining a leaf, flower or fruit to the plant stem.

Pe ole: Peduncle or a type of stalk on a leaf through which it joins the stem.

Phanerogams: Flower-producing, vascular (featuring xylem and phloem) plants.

Phloem: A phanerogam’s vascular ssue, which transports sugars and nutrients in ascending and descending direc ons, from the organs that produce them to those which consume and store them.

Photosynthesis: It is a process in which sunlight’s energy, water, nutrients, plant chlorophyll and carbon dioxide are used to form vegetal ssue (for instance, in the form of sugars, fats or proteins).

Planktonic organisms: Small, o en microscopic organisms that live floa ng in fresh or salt water (they are weak swimmers).

Pollina on: Process through which pollen is transferred from one flower’s stamen (male part of a flower, which produces pollen) to the s gma (recep ve part of a flower).

Primary producers: Organisms that use photosynthesis to produce their own organic material (autotrophs). Primary producers are the beginning of all food chains and webs.

PSU: Acronym standing for Prac cal Salinity Units. It subs tutes the former ppt (parts per thousand). A salinity of 35 PSU is considered a standard seawater salinity.

Rainwater runoff: Rainwater that isn’t readily absorbed by the soil and which then flows across the surface.

Ramified: spreading or branching.

Rhizoid: Structure similar to a plant’s roots, used by algae to anchor themselves to the ground and stabilize themselves. It does not absorb nutrients.

Rhizomes: Subterranean plant stalk, which grows horizontally and from which roots and new shoots may form. Rhizomes aid a plant’s rapid spread throughout an area.

Sedimenta on: Process of sediment accumula on and deposi on.

Sprout: A plant offshoot, which may include stems and leaves.

Stamen: Masculine part of the flower, which produces pollen.

S gma: Part of the gynoecium or pis l (female parts of the flower) that receives the pollen during pollina on.

Substrate: Surface on which an organism lives.

Supra-li oral zone: Part of the coast which does not flood with the des (it is above the upper limits of the high de).

Vascular plants: Plants presen ng a vascular system (xylem and phloem) with which to distribute water and nutrients throughout the plant.

Xylem: Vascular plant ssue which transports water and inorganic salts that serve as nutrients. This occurs in an ascending manner throughout the plant, providing addi onal support.

References:

Blanchon, P., Rodríguez R. (2010). Seagrass. Retrieved August 17, 2013 through h p://www.icmyl. unam.mx/arrecifes/seagrass.html

Den Hartog C. (1970). The sea-grasses of the world. North-Holland Publ. Amsterdam

Fourqurean, J. W., Duarte, C.M., Kennedy, H., Marbà, N., Holmer, M., Mateo, M. A., Apostolaki, E. T., Kendrick, G. A., Krause-Jensen, D., McGlathery, K. J. & Serrano, O. (2012). Seagrass ecosystems as a globally significant carbon stock. Nature Geoscience (5), 505–509. doi:10.1038/ngeo1477.

Green E.P and Short F.t. (2003). World Atlas of Seagrasses. Prepared by the UIMEP World Conserva on Monitoring Centre. University of California Press, Berkeley, USA.

González Lagoa, J.G., González Toro, C. (2010). Encuentro con el mar. Puerto Rico: Sea Grant Program.

Mar nez Daranas, B.R. (2007). Caracterís cas y estados de la conservación de los pastos marinos del área de interés del archipiélago Sabana-Camagüey, Cuba. Thesis presented as a requirement for obtaining a PhD in Biological Sciences. Accessed through: h p://www.oceandocs.net/ bitstream/1834/3405/1/Mar nez-Daranas%20ThesisPhD.pdf

McKenzie, L. (2008). Seagrass Educator Handbook. Seagrass-watch. Retrieved August 17, 2013 through h p://www.seagrasswatch.org/Info_centre/educa on/Seagrass_Educators_Handbook.pdf

McKenzie, LJ., Yoshida, RL. & Coles, RG. (2006 - 2012). Seagrass-Watch. Retrieved August 17, 2013 through h p://www.seagrasswatch.org

Seagrass outreach partnership. (2007). Seagrass… it’s a live. Retrieved August 17, 2013 through http:// archive.li/hi5HZ

Thompson, A. (2012). What is a Carbon Sink? Retrieved July 8, 2014 through h p://www.livescience. com/32354-what-is-a-carbon-sink.html