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Dia 2 Campanha Seward Johnson - A guest post from Gustavo Duarte

Gustavo Duarte is a PhD student with the Abrolhos expedition.  Here, he describes for Portuguese readers, Day 2 of the research cruise.  Gustavo has a blog at IPAq; you can read more there.


Ontem o que fizemos basicamente foi combinar toda a estratégia de coleta para hoje. O submersível estava agendado para descer as 8:00 da manhã com dois pesquisadores: Clovis Castro, meu orientador do Museu Nacional e Shirley Pomponi, do Harbor Branch, além do piloto e do co-piloto.

O mergulho foi um sucesso total. Foram trazidas várias espécies de mar profundo. O destaque foi uma belíssima estrala do mar, vários caranguejos bem diferentes, um lirio do mar e várias espécies de corais vivos.

A temperatura da água durante o mergulho foi de 6˚C aos 700 m subindo para 8˚C aos 450 m. Na verdade o submersível desce até a profundidade máxima do mergulho e vai junto ao fundo até a profundidade mínima e então sobe a superfície.

Os corais estão nos aquários que estão por sua vez dentro de uma câmara fria, a tal “environmental chamber”. Lá eu tenho água do mar corrente saindo de uma torneira. Montei os fragmentos num suporte usando superbonder gel e depois durepoxi. Se sobreviverem até amanhã vou alimentá-los com naupilios de artêmia e plancton coletado pelo navio.

Deu muito trabalho triar todo o material, veio muita coisa diferente. Mais a noite eu tento postar as fotos. Agora estamos fazendo coleta de água em várias profundidades para medir nutrientes, penetração da luz, níveis de clorofila, temperatura, tudo isso de acordo com a profundidade. Um pesquisador a bordo vai filtrar esta água e congelar o material a -80˚C para análise genética dos microorganismos presentes na coluna d’água. Para isso estão usando um CTD com uma rossette.

As 4 da tarde faremos um mergulho mais raso, que começará em 120 m e terminará em 70 m. Coletaremos amostras de corais com zooxantelas e eu medirei a resposta fotossintética destes organismos. Depois, usando uma serra copo, vou retirar uns plugs de cada coral e no laboratório do Rio iremos medir a clorofila das amostras, a microbiota associada bem como uma contagem de zooxantelas.

Com isso esperamos conhecer um pouco mais destes corais que conseguem fazer fotossíntese em regiões tão fundas.


Diving is like a box of chocolates...

…You never know what you’re going to get.  In this video, the Johnson Sea Link (JSL) is recovered after the first dive of the Abrolhos2011 Expedition.  Brazilian scientist Clovis Castro was aboard with HBOI scientist Shirley Pomponi. 

Afterwards, the science team went to work processing invertebrate samples including gorgonians, the hard coral Lophelia, and a range of brittle stars, crinoids, urchins and miscellansous crustaceans

The Brazilian science team evaluates their first samples. L-R Gustavo Duarte, Clovis Castro, lead scientist Rodrigo Moura and Ronaldo Francini-Filho


Reporter Glenda Koslowski with Brazilian scientists (L-R) Gustavo Duarte, Clovis Castro, Rodrigo Moura and Ronaldo Francini-Filho


PhD student Gustavo Duarte takes Lophelia fragments for cultivation

 Alex Bastos with a fine carbonate mud sediment core from 600m



Day 1 cruise track

Here’s our Day 1 cruise track, taking us from Nova Viçosa out to a way point and thence to the R/V Seward Johnson.  Right click the link and save, then  open in Google maps or Google earth


Rocking the Abrolhos

This is the first post from onboard the R/V Seward Johnson, currently at 18 deg 6 min S, 38 deg 25 min W, somewhere off the coast of Bahia State, Brazil.


Alex Bastos likes rocks.  Biologists may scoff, but the truth is that rocks and geology provide the context for biology in the oceans, much the same way as a playing field provides the context for a game of football.  In an expedition concerned with coral reef ecology, then, it’s important to have a thorough understanding of geological processes, because they shape the history of the reef and can help predict its future.  Dr. Bastos, who hails from the Federal University of Espirito Santo, is a marine geologist with a special interest in the Abrolhos.  He is trying to understand what has happened in the prehistoric past and what is happening on the reef today by reading the shape of the bottom features (what geologists like to call morphology) and reconstructing a story and past and present events on the Abrolhos shelf.  Scientists call this sort of activity “inferring process from pattern”, and in terms of marine geology it brings with it some special challenges.  The biggest of these is that, for the most part, Alex can’t see the morphology he wants to study, certainly not as easily as a terrestrial geologist might fly above a mountain range and read the faults and synclines of the landscape to understand what geological forces shaped the land.  No, he has to construct his story a piece or two at a time, like putting together a jigsaw puzzle, often from indirect evidence.  He gets his jigsaw pieces from some pretty cool technology though, including seismic equipment, side scan sonar and by drilling cores out of the sediment.

Side scan sonar is an especially great tool that has become really popular in research circles in recent years.  It uses sound to reconstruct bottom morphology by sending out high frequency noises and then gathering back the echoes off the bottom, much the same way bats find food.  What makes side scan different from regular sonar is that instead of aiming the sound straight down under the boat, it is directed away to each side.  Since the sound hits objects and bounces back at an angle, any structure of any height will cast a sort of sound “shadow” on the side facing away from the boat.  The resulting image is a plan view, but with shadows that reveal shapes and structures, rather like taking a photo from an aeroplane late in the day, when shadows are long on the ground.

Side-scan reveals and ancient river channel. Img: Alex BastosBy combining studies of morphology with reconstructions of sea level at different times in geological history, Alex tells a story about the way the Abrolhos platform evolved.  Around 40 million years ago the main playing field was established by a flood of volcanic basalt that spread out to create the basis of the platform.  In the ensuing geological periods, carbonate rocks (i.e. limestone) were deposited, implying that reefs existed there at times in the distant past (my assertion in a previous post that there were no reefs on Abrolhos before 8,000 years ago was wrong).  During the last ice age, the sea level was over 100m lower than its current height, so much of the platform, including the locations of all the current shallow coral reefs, was above the surface.  At that time, a central depression in the platform was probably still filled with water, forming a shallow coastal lagoon opening to the south.  The Caravelas River probably drained into this lagoon from the north, cutting a number of different channels through the limestone as it meandered over time.  The river also provided a source of sediment that fanned out off the edge of the platform from the mouth of the lagoon.  All three of these features – the shallow depression, the channels in the limestone and the sediment fan – are still there on the bottom of the sea and help to tell the story.  At the end of the last ice age came the last great transgression, when sea level rose to approximately its current levels.  The entire platform was flooded, and corals once again colonized the platform and began to grow up towards the surface to where we see them today.

How Abrolhos might have looked during the last ice age; note the central lagoon opening to the south

Current bottom topography of Abrolhos; note central depression due south of the islands

Holocene sedimentary processes.

Unfortunately, morphology only gets you so far.  Knowing the history of the platform, many of Dr. Bastos’ questions now relate to what has happened since the last transgression, during the most recent geological period (the Holocene), and most of these need other methods to answer.  These questions include “Is all the sediment on the platform a relict of geological history, or are sediments actively being deposited to this day?” and “If they are still being deposited, do they come from the land via the river, or are they produced in the ocean by corals, coralline algae and other organisms?”  To answer these questions, Alex will use a combination of seismic methods and sediment cores.  Seismic surveys provide indirect evidence of the nature of sediments below the surface of the sea bed, and these can be calibrated or “ground-truthed” by taking sediment cores that will reveal a timeline of sediment history on the platform.  These geological questions played a large part in the choice of sites for the main transects on this expedition.  One is to the south, in the mouth of that ice-aged lagoon, on the edge of the shallow-sloping fan of sediment.  The other is in the north, on a much steeper shelf break where the platform gives way to the deep sea beyond.  These two locations not only have profoundly different geology, but it’s likely that organic processes differ between them too, as we shall see in a future post.

Applying the lessons

Alex was telling me that one of the more satisfying aspects of his work is translating geology data into benthic (bottom) habitat maps.  In other words, taking all that information from the sonar morphology, the seismic data and the sediment cores, and mapping out what different parts of the platform are like on the bottom.  This is important, because once scientists can say with confidence that Area X is a rhodolith bed, or Area Y is a steep-sided valley, then they can predict with good accuracy what sorts of organisms will live there.  That sort of information is of critical value when deciding where to take biological samples and even more so when the Ministry of the Environment needs to make decisions about the boundaries of protected areas, which they are currently doing.  In this way geology plays a very important role in both the biological sciences and in conservation decision making.


Welcome aboard!


Getting down to the nitty gritty

How deep can we go?  How can we collect fish?  How much water can we sample at once?  These are just some of the questions that filled today’s planning session in Vitoria for the Abrolhos 2011 expedition.  They’re not straightforward questions to which some resident authority has a simple answer.  No, when you’re planning work between 300 and 3000 feet down, no questions are simple, and nor are the answers easy; rather, they are crafted through a careful group discussion of what’s a priority, what’s possible, what’s practical, and what we have time for.  In other words, its not all The Life Aquatic, its large parts careful planning and preparation.

The day started with presentations from representatives of Cepemar, Harbor Branch and the Rosenstiel School of Marine Science at U. Miami.  After that, Rodrigo Mouraled the planning session where we talked reef biology for hours, fueled (as all the best science chats are!) by shots of excellent Brazilian coffee.  Dr. Moura is a faculty member at Santa Cruz University and a consulting scientist with Conservation International, who have a substantial marine conservation program focused at Abrolhos.  He explained all the things that make Abrolhos unique, from the 40,000km2 platform on which they occur, to the unique fauna and dominance of shallower reefs by the endemic coral Mussismilia braziliensis, to the unusual mushroom formation of these reefs (chapeiroes), and finally to the history of human impacts and conservation efforts surrounding these unique ecosystems and the deeper and less-known seafloor habitats around them.  The Abrolhos Marine National Park was the first marine national park in Brazil, established in 1983, but like many reefs it faces its fair share of threats from pollution, global climate change and marine development.

 Suitably up to speed on the history and context for the expedition, the next speakers were the 8 principal investigators to give details of the motivations for their respective parts of the expedition, and to outline their specific sampling needs.  Alex Bastos, a geologist from the Federal University of Espirito Santo, talked about the geological history of the platform, how its central depression was likely once a shallow coastal lagoon during the last ice age, and how taking samples of sediment from the bottom will explain more about how the reef came to be and how much it contributes to calcium carbonate production in that part of the Atlantic. Paulo Sumida from the University of São Paulo explained how organic matter (carbon based material either secreted from living organisms or leftover by dead ones) is distributed unevenly across the platform, with more in the south and less in the north.  We learned from Mauricio Torronteguy’sgroup at Cepemar how water sampling and measurements of the properties of the water overlying the reef would be used to provide a better understanding of the biology taking place on the reef.  Microbiologist and geneticist Fabiano Thompson from the Federal University of Rio de Janeiro explained what has been learned about the importance of Vibriobacteria on the reef, both as potential agents of disease in corals and, surprisingly, as possible agents of photosynthesis; i.e. food production from sunlight.  Vibrios were not previously known to use light for food, so this is potentially big news.  His graduate student, Nelson Alves, will be sampling for water-borne viruses by looking for their DNA signature.  These aren’t viruses as we know them (causes of A rhodolith bedhuman disease), but a natural and dominant part of the very smallest members of the plankton, whose importance has only been realized in the last few years.  Gilberto Filho, who is a head botanist at the Botannic Gardens in Rio de Janeiro, talked about the importance of rhodolith beds, which are an unusual sort of habitat made up of softball-sized lumps of reddish rock that are produced by algae that are able to secrete calcium skeletons as they photosynthesise, much like corals do.  These lumps then become substrate for all manner of other things to live on, since they are hard and rigid, unlike the soft, shifting sediments on which they sit.  In this way, rhodoliths can increase the diversity of a patch of otherwise empty seabed.  Ronaldo Francini-Filho talked about what is known and not known about some of the bigger critters that make up the reef community, like fish and larger invertebrates.  The final presentations from National Museum scientist Clovis Castro and student Gustavo concerned deep-sea corals of the Abrolhos, including those that use light and have symbiotic algae in their tissues (zooxanthellate) and those that lack algae and feed by filtering plankton or absorbing organic material directly from seawater (azooxanthellate).  We’ll learn more about each of these projects in coming days, so if you have questions for the researchers, by all means post them in the comments below. 

The hardest part of planning a research trip came next: deciding how on earth we’re going to meet everyone’s needs within a limited timespan, using the assets of the ship and the brain trust of people aboard it.  This is where the beautiful ideality of a proposed sampling scheme meets the stark and sometimes gruesome reality of what you can, practically speaking, actually do.  All scientists, especially biologists, know and dread this bit; indeed, Mmmmm…mesophotic reefs…argleargle….a lot of the very best biologists are those that have mastered this challenging process and can come up with intelligent and efficient sampling schemes that provide maximum bang for the research buck and minimize down or wasted time.  The upside of this process is that as everyone thinks and talks, you start to see the days to come materializing before you, and a sense of very real excitement sets in.  Ahead lie mornings spent deploying the submersible, afternoons sorting samples of sediment, deep sea corals and sponges, and evenings spent measuring water column properties with a CTD/Rosette and ADCP (more on these later).  It’s enough to make any marine scientist practically drool with anticipation. 


U.S. and Brazilian researchers

Scientists from Harbor Branch and Brazilian universities in Vitoria Skype with operations staff aboard the RV Seward Johnson off the coast of Bahia, to plan submersible activitiesas part of the Abrolhos 2011 expedition.


The start of something beautiful

My travelling partner Kristie Cobb (Georgia AquariumVP) and I arrived in Brazil today for the Abrolhos 2011 expedition.  The flight in from Atlanta is long (10hrs) and a red-eye, so we arrived a little the worse for wear in Rio.  As we flew, I was considering the similarities and differences between Brazil and Australia.  Brazil’s great mountain range is to the west and is immense in both length and height: the Andes.  It circumscribes the Amazon basin, the most spectacular crucible of biodiversity on the planet.  It drains to the eastern seaboard, which has some coral reefs (including the ones we’ll survey), but nothing like the Great Barrier Reef.  By contrast, Australia is mostly a giant flat arid zone (Google the awesomely ominous sounding “yilgarn kraton” to learn more) with its “great” mountain range on the eastern coast, where a once-active subduction zone scraped off enough Pacific sea floor to make a strip of lan on which >75% of Aussies live.  I say “great” because even the highest of the Snowy Mountains is a pimple compared to the Andes.  There are rainforests in appropriate microclimate pockets along the great dividing range, sure, but not like the vast unending ones we flew over today; there just isn’t the volume of reliable rain (recent floods notwithstanding).  Partly as a result of that tiny eastward drainage and low rainfall, the tropical coastal waters of north eastern Australia are nutrient poor and therefore ideal for coral reefs; accordingly, the Great Barrier Reef is the Amazon rainforest of reefs.  They are two countries with priceless biodiversity treasures, of totally different kinds, as dictated by the constraints of their respective geological histories and their prevailing climates.

We came within three miles of the mighty Amazon today; it was just a pity that it was a vertical three miles!

During an awkwardly long layover in Rio de Janeiro, we decided to bail on the airport and make a lightning visit to the famous Christ the Redeemerstatue; a gargantuan art deco edifice that presides over the spectacular sprawl of beachfront hi-rises and mountain-clinging favelasbelow.  I’m really glad we did too, because the views were stunning and the statue itself a marvel; I’m not a religious guy, but you have to admire the inspiration that drives people to conceive of and build such things on that tiny inhospitable peak at the top of Corcovado.

Christ the Redeemer statue, Rio de Janeiro

After that we made our connection to Vitoria, in the state of Espiritu Santu, north of Rio.  Here we will meet up with our Harbor Branch and Brazilian colleagues for a research co-ordination meeting tomorrow; then a short charter flight to meet the R/V Seward Johnsonat our port of departure in Bahia state.  Right now though, it’s caipirinha o’clock!


Which came first, the Abrolhos or the Abrolhos?

In just a couple of days I’ll join a group of scientists from Brazil, Australia and the US for an expedition to study the reefs of the Abrolhos platform, off Bahia state in Brazil.  When this trip was first mentioned I have to admit being confused.  That’s because, as a native Aussie, to me “the Abrolhos reefs” means a group of reefs and emergent islands off the remote Northwest coast of Western Australia.  So why are there two Abrolhos Reefs, and which came first?

My Brazilian friend and colleague Julia Todorov tells me that Abrolhos is a contraction of two Portuguese words, abro and olhos, meaning “open eyes” as in “Keep your eyes peeled, Marcos, lest you plough the ship into the reef!”.  That etymology is listed in several online sources.  The above Wikipedia link for the Aussie Abrolhos, however, says its not a true etymology, but I don’t see why not, since it applies just as well to reefs as it would to caltrops: basically, watch where you’re going!

Frederick de Houtman (Wikimedia commons)None of that explains why the Aussie reefs got the name, since the Portuguese did not explore Australia that we know of.  Nor does it explain which place name came first.  That’s a bit easier.  The Australian reefs are properly called the “Houtman Abrolhos” or “Frederick de Houtman’s Abrolhos” and were named by de Houtman, the captain of the Dutch East India Company ship Dordrecht in 1619.  He almost certainly named them after the Brazilian reefs, which he had previously sailed through in 1598.  The Brazilian reefs were already known and named at that time, so by name, the Brazilian Abrolhos came first.

Putting the trivialities of human history aside for a moment, we might ask a bigger question: which Abrolhos ultimately came first? Y’know, biologically.  Which reef grew up from the seafloor first?  In short, it was a tie.  Both reefs showed a major growth spurt around 8,000 years ago in the midst of the “last transgression”, when sea level started rising as the ice caps melted away from the last ice age.  This is a pretty common pattern everywhere.  In fact, there are pretty much no extant coral reefs anywhere older than about 12,000 years, since they were all high and dry back then (the reef organisms having receded into what are now much deeper areas).

OK then, if the current reef communities of the Abrolhoses (?) are both about the same age, then which reef came first geologically?  Which one has the longest geological history?  Chalk that one up as a win in the Houtman column.  The current  Houtman Abrolhos islands and reefs sit atop limestone bedrock that is the remnant of a coral reef that grew in the same location in the Quaternary period, before about 125,000 years ago.  The Brazilian Abrolhos, on the other hand, sit atop a layer of flood basalts (i.e. volcanic rocks, solidified lava) that spread out across the edge of the continental shelf during the Eocene (>30 million years ago).  When scientists core into the reef, the oldest reef they find before they hit the volcanic layer is a bit over 7,000 years; suggesting that the Brazilian reefs are relatively much younger (see Dillenburg & Hesp, 2009

The Houtman Abrolhos in Australia. (Wikimedia commons)Aside from the name and the similar recent growth spurt, the Abrolhos reefs have little in common; Houtman Abrolhos is a faily typical Indo-Pacific reef with high coral, invertebrate and fish diversity growing on a relict of an even older reef, whereas Brazilian Abrolhos is species poor and dominated by just a few coral and fish species growing on a volcanic base.  Could the short geological history of the Brazilian Abrolhos account for the biological differences?  Maybe, but biogeography probably has a lot to do with it too.  Houtman Abrolhos are not too far from the Indo-Pacific center of diversity, the highest tropical diversity there is and source of much species richness throughout the Indo-Pacific, whereas Brazilian Abrolhos are remote and cut-off from other major centers of reef diversity.  There will be a lot more to talk about regarding the diversity in Brazilian Abrolhos in future posts.

So the Aussie Abrolhos has probably been around quite a bit longer, but the Brazilian Abrolhos has been known to people (European at least) longer by about 100 years.  Despite this, the Brazilian reefs are still poorly known, having come to research and conservation attention only for the last two decades or so.  Its fantastic to think that on this expedition we will still have so much to learn about such a unique ecosystem.  I look forward to reporting  from onboard the R/V Seward Johnson some new biology in the Brazilian Abrolhos, starting later this week.  I hope you’ll stick around and join in the conversation.


Abrolhos, here we come!

Mussismilia braziliensis at the Abrolhos Reefs, BrazilThings have been a little quiet around here over the holiday break, but that’s about to change in a big way.  In just under a week’s time, I’ll be representing Georgia Aquarium in a new international consortium of scientists for an exciting expedition to explore the Abrolhos reef platform off the coast of Brazil from January 20-28.  The Abrolhos are completely unique reefs: they’re the largest and southernmost in the South Atlantic and biologically very different from perhaps more familiar Pacific or Caribbean Reefs.  You’d think they might show some similarity to Caribbean reefs, but not so, possibly because unfavourable currents and the influence of the Amazon pouring into the ocean between the two may serve as an important barrier to animal dispersal (more on that in future posts).  There’s tremendously high endemicity there, which is to say that many of the resident critters are found nowhere else in the world.  Of key importance is the main reef-forming coral Mussismilia braziliensis, a massive species that forms an unusual bommie-like reef structure called a mushroom reef; we’ll meet this species in more detail later too.

The main aim of the expedition is actually to go a bit deeper than the known parts of the Abrolhos, and look at the depths where light starts to get dim: the mesophotic zone.  These parts of many reef platforms are poorly known and nowhere moreso than at Abrolhos, where these areas are completely unexplored.  That’s because mesophotic reefs are beyond comfortable SCUBA diving range and therefore hard to get to.   To study them between 300 and 3,000ft in depth, we’ll be using the Johnson Sea Link, a submersible that operates from the R/V Seward Johnson, which is on a 5 year assignment from it’s home at Harbor Branch Oceanographic Insitute to CEPEMAR, a Brazilian environmental services company.

The Johnson Sea Link and R/V Seward Johnson

There’s much more to come in future blog posts here and in my tweet stream @para_sight or using the hashtag #Abrolhos2011.  We’ll discuss the Abrolhos reefs, mesophotic reefs, some geology and biology, as well as meeting the people and partners and exploring the logistic challenges of making a complex expedition like this happen.  So, I encourage you to follow along and also to share this information with colleagues and (especially) students of marine science so that they might also follow and share in the excitement of discovering new parts of the ocean floor, never seen before, in tropical Brazil.

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