Friday, December 23, 2016

12 Creatures on Buccoo Reef to cherish all year round

In observance of the season of celebration and thanksgiving, Jahson Alemu shares 12 creatures special to Buccoo Reef that we should cherish and protect. Make a note for 2017 to appreciate the marine environment that surrounds Trinidad and Tobago. Without it, we are rocks in the ocean, black dots on the map.  Follow Jahson on twitter: jahson_alemu

Christmas is in the air. The smell of pastelles, black cake, ham and all sorts of seasonal goodies tantalise our taste buds. From simple to intricate lights adorn houses; and like moths drawn to a flame, paranderos flitter from house to house to spread joy, serenade and wish us well for the season. In the spirit of the season, here is a Christmas tribute to some of the creatures that add vibrancy, wonder, colour and life to our Buccoo Reef.

Red Cushion Starfish, photo courtesy Jahson Alemu

On the first day of Christmas,
My true love gave to me,
One Red Cushion Starfish (Oreaster reticulatus).


Two French Angelfish, photo courtesy Jahson Alemu

On the second day of Christmas,
My true love gave to me,
Two French Angelfish (Pomacanthus paru), and
One Red Cushion Starfish



Three bottlenose dolphins, photo courtesy Jahson Alemu
On the third day of Christmas
My true love gave to me,
Three Bottlenose Dolphins (Tursiops truncates),
Two French Angelfish, and
One Red Cushion Starfish.


Christmas Tree Worm, photo courtesy Jahson Alemu
On the fourth day of Christmas
My true love gave to me
One Christmas Tree Worm (Spirobranchus giganteus)
Three Bottlenose Dolphins
Two French Angelfish, and
One Red Cushion Starfish


Batwing crab, photo courtesy Jahson Alemu
On the fifth day of Christmas
My true love gave to me
One Batwing Crab (Carpilius corallines),
One Christmas Tree Worm
Three Bottlenose Dolphins
Two French Angel Fish, and
One Red Cushion Starfish


Black Grouper, photo courtesy Jahson Alemu
On the sixth day of Christmas
My true love gave to me
One Black Grouper (Mycteroperca bonaci)
One Batwing Crab
One Christmas Tree Worm
Three Bottlenose Dolphins
Two French Angelfish, and
One Red Cushion Starfish.


Brain coral, photo courtesy Jahson Alemu
On the seventh day of Christmas
My true love gave to me
One giant Brain coral (Colpohyllia natans)
One Black Grouper
One Batwing Crab
One Christmas Tree Worm
Three Bottlenose Dolphins
Two French Angelfish, and
One Red Cushion Starfish


Rainbow Parrotfish, photo courtesy Paul Asman and Jill Lenoble
On the eight day of Christmas
My true love gave to me
One Rainbow Parrotfish (Scarus guacamaia),
One giant Boulder Brain….coral
One Black Grouper
One Batwing Crab
One Christmas Tree Worm
Three Bottlenose Dolphins
Two French Angelfish, and
One Red Cushion Starfish.


Long-spined sea urchin, photo courtesy Jahson Alemu
On the ninth day of Christmas
My true love gave to me
One long-spined sea urchin (Diadema antillarum)
One Rainbow Parrotfish,
One giant Boulder Brain ... coral
One black grouper
One Batwing Crab
One Christmas Tree Worm
Three Bottlenose Dolphins
Two French Angelfish, and
One Red Cushion Starfish.


Queen Angelfish, photo courtesy Laszlo Ilyes
On the tenth day of Christmas
My true love gave to me
One Queen Angelfish (Holacanthus ciliaris)
One long-spined sea urchin
One Rainbow Parrotfish,
One giant Boulder Brain….coral
One black grouper
One Batwing Crab,
One Christmas Tree Worm
Three Bottlenose Dolphins
Two French Angelfish, and
One Red Cushion Starfish.


Spotted eagle ray, photo courtesy Laszlo Ilyes

 On the eleventh day of Christmas
My true love gave to me:
One Spotted Eagle Ray (Aetobatus narinari)
One Queen Angelfish
One long-spined sea urchin
One Rainbow Parrotfish,
One giant Boulder Brain….coral
One black grouper
One Batwing Crab,
One Christmas Tree Worm
Three Bottlenose Dolphins
Two French Angelfish, and
One Red Cushion Starfish.



Buccoo Coral Reef, photo courtesy Jahson Alemu


On the twelfth day of Christmas
My true love gave to me: a healthy coral ecosystem with
One health coral reef
One Spotted Eagle Ray
One Queen Angelfish
One long-spined sea urchin
One Rainbow Parrotfish,
One giant Boulder Brain….coral
One black grouper
One Batwing Crab,
One Christmas Tree Worm
Three Bottlenose Dolphins
Two French Angelfish, and
One Red Cushion Starfish.


Merry Christmas and Happy New Year!

Thursday, December 15, 2016

Forests on the Edge

Jahson Alemu, marine biologist, discusses the importance of mangrove ecosystems to the enhancement and protection of coastlines, and also to our future. This feature was first published in the Tobago Newsday on Thursday December 15, 2016
Follow Jahson on twitter: @jahson_alemu.

If trees are the lungs of the earth, mangroves must be the kidneys. Like botanical amphibians, mangroves live life on the edge. Uniquely positioned at the dynamic interface between land and sea, they are highly productive tropical coastal ecosystems comprised mainly of trees and shrubs capable of thriving in humid heat, amid choking mud and salt levels in which only a few plant species can survive (Duke et al 1998). If you’ve never seen a mangrove, picture a lattice of tangled tree legs rising up from brackish water. At one point in our history, mangrove forests were treated as wasteland considered only useful as dumps, and haven to bad spirits, jumbies, runaways and criminals.

Red mangroves (Rhizophora mangle) and intertwining prop roots in Bon Accord Lagoon. Photo by Jahson Alemu I, 2014
The mangrove swamp was avoided and condemned as breeding ground for disease, mosquitoes, frogs, snakes and other beasties the mind could imagine. At the same time, however, they were important sources of building material, firewood, medicine, food security (agriculture), homes for the poor, recreation and harbours for small boats. Today, mangroves have taken on additional meanings in our lives, where as well as the traditional roles, they now act as sources of revenue through ecotourism; major agents of soil stabilisation, coastal expansion and erosion control where interlocking roots stop land-based sediments from coursing out to sea. They build land, and their trunks and branches serve as barriers that diminish the erosive power of waves; and a climate regulators they store vast amounts of carbon that would otherwise be released into the atmosphere.

As discussed in last week’s article, they provide the unique requirements to create bioluminescent bays. But, probably one of the most well known roles of mangroves is as a home to wildlife (e.g. Scarlet Ibis) and nursery to fish and shellfish (e.g. spiny lobsters, snappers, tarpon and grouper). Altogether, these ecosystem goods and services have been valued globally at approximately US$32 billion annually, which translates to approximately US$194,000 ha-1 yr-1(Costanza et al 2014).

Despite their importance, our mangrove forests continue to be threatened and are rapidly declining. Significant alterations to mangrove forests in Trinidad and Tobago since the early 1970s have already resulted in an estimated 20% loss of mangrove forests due mainly to population growth and increasing development in coastal areas. Several examples illustrate these threats including decades of continued modification, built development encroachment: squatting and agriculture in the Caroni Swamp; the phenomenal shrinkage of the Friendship and Kilgwyn Swamps following necessary mangrove clearing for the Crown Point Airport runway expansion (IMA 1990); and development of the Canoe Bay Resort in 1980. Similarly, proposed resort and housing developments threaten the integrity of the Buccoo Bay mangrove forest. While there is growing recognition of the importance of mangrove forests, to date we have only managed to offer limited protection to three mangroves systems: Caroni Swamp, Nariva Swamp and Bon Accord Lagoon.

Coastal flooding and increased coastal erosion are but two of the major impacts we expect over the next 50-100 years if mangroves continue to shrink. In a recent review, the Institute of Marine Affairs described the state of mangrove conservation in Trinidad and Tobago as greatly challenged because of inadequacies in existing laws and institutional arrangements. If there is to be any meaningful slowing of the current rate of mangrove degradation and loss, an Integrated Coastal Zone Management (ICZM) approach is recommended as a means to promote coordination and clear distribution of responsibilities among the various authorities with jurisdiction over mangrove management.
The national bird, Scarlet Ibis (Eudocimus ruber), spends most of its life feeding and nesting in mangrove forests. Photo courtesy Charles J Sharp, 2014

 In spite of all these challenges, our environmental consciousness has increased tremendously over the last decade, and so too has our understanding of the role of mangroves in an uncertain future. Mangroves represent real opportunities for livelihood development (such as ecotourism, education, management); food security through the maintenance of juvenile fisheries stocks, biodiversity conservation especially of endangered species (e.g. goliath grouper/jewfish). In small islands such as ours, we are extremely vulnerable to climate change impacts, as such mangroves also represent important ecosystems for climate regulation and coastal resilience. Any development in or around these ecosystems should strive to have minimal impact on the mangrove forests, allowing them to thrive in their special relationship between the shore and sea.


References:
Costanza R, de Groot R, Sutton P, van der Ploeg S, Anderson SJ, Kubiszewski I, et al. (2014) Changes in the global value of ecosystem services. Glob Environ Chang. 26: 152–158
Duke NC., Ball MC and Ellison JC (1998). Factors Influencing Biodiversity and Distributional Gradients in Mangroves. Glob. Ecol. Biogeogr. Lett. 7, 27  1996,
IMA (1990) Environmental Impact Assessment of the extension of Crown Point Airport Runway, Tobago. 123pp
Juman R and Ramsewak D (2013). Status of Mangrove Forests in Trinidad and Tobago, West Indies. Caribbean Journal of Science, 47(2-3), 291-304.
Juman R and Hassanali K (2013) Mangrove Conservation in Trinidad and Tobago, West Indies (pp. 35-64) in (eds) Gleason G and Victor TR (2013). Mangrove ecosystems: biogeography, genetic diversity and conservation strategies. Environmental research.




Thursday, December 8, 2016

Lights in the Lagoon



Jahson Alemu discusses the phenomenon known as bioluminescence, and conditions where it thrives: the protected Bon Accord Lagoon in Tobago is one of these rare spots.. Jahson is a marine biologist completing his PhD study on Buccoo Reef and its value in the ecosystem of south-west Tobago. This feature was first published in Tobago Newsday on Thursday, December 8, 2016
Follow Jahson on twitter: @jahson_alemu.

Imagine a world without light!
That may seem difficult to imagine and it is likely you don’t think about it often! But for several animals part of their lives are spent in absolute darkness (such as at night or in the deep sea), and as such, they have evolved to cope with life in darkness by producing their own light, much like fireflies. This ability is called bioluminescence and simply put, it is the production of light due to an internal chemical reaction. More technically, it is the light energy produced as a result of the interaction of the compound luciferin with oxygen catalysed by the enzyme luciferase. Regardless, bioluminescence allows organisms to produce their own light, which we see as glowing in the dark, and the darker it is, the more intense the glow. This ability is used quite often in the marine environment by several species to attract prey (e.g. anglerfish), scare away or confuse predators (e.g. plankton), to attract mates (e.g. lanternfish), and even to communicate (e.g. plankton and squid). Interestingly, dinoflagellates (tiny unicellular bioluminescent marine plankton), are the most commonly seen example of bioluminescence.

I’ll never forget the excitement I felt when I first saw bioluminescence as the ocean shimmered in fleeting sparkles of green around Gasparee Island. I would have the same feeling several years later while on a night dive in Tobago, where as I descended to 100ft, with every motion, ghostly threads of green and yellow trailed behind me. But it wouldn’t be until 2014 while on a bioluminescence tour with Radical Sports in the Bon Accord Lagoon that I would be awed by the cinema of living light.

The Bon Accord Lagoon, Tobago, is one of those rare places (called biobays) where conditions are right for bioluminescence. Photo courtesy Islands of Trinidad and Tobago

There was no moon and it got darker as we paddled into the lagoon. But with every stroke our bows and paddles would glow. This was no gimmick, this was bioluminescence. Pretty soon we were seeing glowing fish darting about, and the bubbles they left also glowed which showed us where they came from. There was even a ray. Nothing moving in the water was hidden. The cause of this were bioluminescent dinoflagellate plankton (unicellular algae of the kingdom Protista). These microorganisms are autotrophic and produce their own energy through photosynthesis. What is most unique about them is that they use part of this energy to emit a bright flash of light whenever they are disturbed. The lagoon is rich with plankton, at concentrations high enough to produce this effect and as such is described as a biobay (bioluminescent bay).


Swim in light! Photo courtesy Radical Sports Tobago

Biobays are rare ecosystems that occur when microscopic organisms called dinoflagellates thrive in numbers large enough (and under the right conditions) to produce a glow-in-the-dark effect when they are stirred to action such as, by a fish or paddle. And when they glow, so does anything that comes in contact with them. As our paddles entered the water, the agitation excited the plankton, and flashed blue-green from our bows and paddles with every stroke. Scientist believe that the flash is meant to simultaneously attract a predator and to surprise the cause of the disturbance, with the result being a decreased likelihood of the dinoflagellate being eaten. 

Squid with small light organs on the underside of its body for camouflage. It uses this illumination to blend in with the sky, hiding its silhouette from predators watching from below. Photo courtesy Steve Haddock/Monterey Bay Aquarium Research Institute


The Bon Accord Lagoon is a protected inlet in Tobago’s protected marine park that holds millions of marine bioluminescent dinoflagellate plankton. The brackish water in this bay (a mix of salt water from the Caribbean and fresh water), combined with nutrients from decaying red mangrove trees (source of vitamin B12 required for dinoflagellate growth) make the area a perfect environment for bioluminescent dinoflagellates to thrive. Because the biobays require such exact conditions in order to form, there are very few in the world, and conservationists work tirelessly to preserve these unique phenomena. Arguably, Petit Trou in Tobago and parts of the Nariva Swamp support similar conditions to support biobays. The single most harmful species to these dinoflagellates are humans.

Current threats to these ecosystems include climate change and land based sources of pollution. Average ocean temperatures have steadily increased around Tobago over the last 15 years, and this rise would be even great for shallow ocean systems such as a lagoon. While plankton are adaptable, it is likely that a critical temperature threshold will be reached beyond which these plankton will not be able to survive. Additionally, waste (particulate or chemical) entering the lagoon can also affect the survival of these organisms; as the dinoflagellates are very sensitive to chemical pollutants such as heavy metals, industrial waste and sewage runoff (Lapota et al., 1993, 2007). Finally, an increase in light pollution in the area can reduce the observance of this phenomenon. 

Ultimately, the maintenance of this unique ecosystem may lie in our ability to protect and conserve our mangrove forest, which support the bioluminescent dinoflagellates and aid in cleaning land-based wastewater that enters the lagoon.


Jahson Alemu Photo by Mark Pierre


References:
Lapota, D., A.R. Osorio, C. Liao, and B. Bjorndal. "The use of bioluminescent dinoflagellates as an environmental risk-assessment tool." Marine Pollution Bulletin 54:12 (December 2007): 1857-67. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/17928009

Lapota, D., G.J. Moskowitz, D.E. Rosenberger, and J. Grovhoug. "The use of stimulable bioluminescence from marine dinoflagellates as a means of detecting toxicity in the marine environment." Naval Command Control and Ocean Surveillance Center (NCCOSC), Naval Facilities Engineering Command, 93-12127. 1993.

Thursday, December 1, 2016

Islands in the Orinoco

To the east of Trinidad and Tobago is the Atlantic, on the west the Caribbean Sea. However, the most powerful influence of water on these islands might be the fresh waters coming off the South American mainland. This week, Anjani Ganase, marine biologist, looks at the mighty Orinoco river whose delta comprises islands many times the size of Trinidad. This feature was first published in the Tobago Newsday on Thursday, December 1, 2016
Follow Anjani Ganase on twitter: @AnjGanase

“When Columbus sailed into the Gulf of Paria he had to make sense of two anomalies. His navigational readings were picking up the earth’s equatorial bulge, and the Orinoco being in spate meant that the water was fresh. Captivated by the apparently friendly natives, the exuberant vegetation, the benign climate and the extraordinary landscape, he called the area Tierra de Gracia (Graceland).”
-John Stollmeyer, Place of Beginnings, the World Views of the Amerindians of Cairi and of Medieval Europe, 2003

Columbus sailed through the Gulf of Paria on 1st August 1498, during his third voyage. It was this occasion that Trinidad and Tobago also marked as our “discovery day” commemorated in Moruga by mock landings of Columbus’ caravels, even though it is commonly thought that Columbus never came ashore.

In August, at the height of the rainy season, the Gulf of Paria would have seemed to the explorer a land-locked lake of fresh (sweet) water. Columbus didn’t stay in the Gulf of Paria but sailed south to the Orinoco delta, the region now called Amacuro, some 40,000 sq km of swampy forested islands.

Almost a hundred years later, Sir Walter Raleigh wrote of his 1595 voyage: “…the great river of Orenoque or Baraquan hath nine branches which fall out on the north side of his main mouth; on the south side it hath seven other fallings into the sea … but the islands are very great, many of them as big as the Isle of Wight… “ He also noted, “between May and September the river of Orenoque riseth 30 foot upright, and then are those islands overflowen 20 foot high above the level of the ground.”

Travel at any time of the year in the delta was necessarily by boat, and Raleigh wrote, “… these people that dwell upon the branches of the Orenoque, called Capuri and Macureo, are for the most part carpenters of canoes, for they make the most and fairest canoes and sell them in Guiana for gold, and into Trinidad for tabacco.”
 
Warao children paddle in the Orinoco delta. Photo courtesy Marc de Verteuil who leads tours up the Orinoco from Trinidad.

Raleigh persevered upriver and “beheld that wonderful breach of waters … more than 20 miles away, and there appeared some ten or twelve overfals in sight, everyone as high over the other as a church-tower, which fell with that fury, that the rebound of water made it seem as if it had been all covered over with a great shower of rain.” One of these mighty waterfalls would have been Angel Falls, the highest in the world. (Angel Falls tumbles off Rio Kerepacupai Meru which flows into a tributary of the Carrao River, itself a tributary of the Orinoco.)

Trinidad and Tobago sits on the continental shelf of South America. Trinidad is 12 kilometres from Venezuela, and Tobago 30 kilometres from Trinidad. Both islands are geological extensions of the mainland. Trinidad’s Northern Range and Tobago’s Main Ridge may be the easternmost extensions of a cordillera of the Andes. It is thought that Trinidad was separated about 11-15,000 years ago. The flora and fauna of our islands are identical to South American populations. A couple species that remain specific to the Orinoco are the pink river dolphin and the endangered Orinoco crocodile (the largartos of Raleigh’s description) which can grow to twenty feet.

The name Orinoco came from Guarauno words meaning “a place to paddle,” a place for transportation or navigation by canoes. It is also uniquely connected to the Amazon by the Casiquiare canal, a hydrographic divide between the Orinoco Basin and the Amazon Basin. The Orinoco flows west–north–northeast into the Caribbean; the Amazon flows east into the western Atlantic in the northeast of Brazil. The Casiquaire is a west-flowing section of Venezuela's Orinoco River with an outflow into the Amazon Basin.

Boat building in the Orinoco delta. 
Photo courtesy Marc de Verteuil who takes tours up the Orinoco from Trinidad.

The Orinoco basin covers an area of approximately 950,000 km2. It is bordered by the Andes to the west and north, the Guyana Highlands to the east, and the Amazon watershed to the south. The river, approximately 2,200 km in length, runs in an arc and its basin occupies an area that is most of Venezuela and part of Colombia.

The Orinoco delta, a region called Amarcuro, is a wide triangle extending about 400 km along the Atlantic coast of Venezuela from Pedernales on the Gulf of Paria to Punta Barima on the Boca Grande. The river flows into the southern Caribbean Sea, its waters bathing Trinidad and Tobago.

The outflow of the Orinoco delta brings a tremendous torrent of freshwater during the rainy season (usually April to November). These outflows bring many terrestrial and freshwater species from South America to Trinidad. It is rich in nutrients, and because it is less dense than seawater, the fresh water remains at the surface. This plume of waters can be observed, in satellite images, emanating from the Orinoco delta enveloping Trinidad and Tobago, and swirling into the Caribbean Sea, as far north as Puerto Rico.
 
Obtained by remote sensing from space, images like this illustrate biological and physical oceanic phenomena. In this view, warm colours are high chlorophyll. (From the Goddard Earth Sciences Data and Information Services Centre NASA)
Orinoco waters are carried around Trinidad and Tobago by what is called the Guiana Current. Tobago is subjected to the full force of this current which divides at the southeast coast; one part flowing in a northeasterly direction, and the other passing between Trinidad and Tobago in a northwesterly direction.

How do we know the Orinoco is flowing past our islands? When you dive in Tobago waters and observe the ocean’s green tint, you are seeing increased chlorophyll concentrations in the fresh water coming off the South American mainland. As much as we might like to identify as Caribbean islands, our South American connection is unmistakable.