For the past 500,000 years, Acropora cervicornis (staghorn coral) was one of the dominant reef building corals in the Caribbean.  But over last few decades, A. cervicornis populations have suffered a dramatic decline (>95% mortality) throughout the entire Caribbean  (Griffin et al 2012).  As a result of this decline, adult populations typically have low densities and genetic diversity, resulting in a reduction in genetic connectivity for this genus.  As these populations continue to decline, proactive intervention is becoming increasingly warranted

In the last decades coral gardening has become an increasing important tool in reef restoration (Lirman 2008).  Coral gardening consists of growing corals in situ at a nursery site and then transplanting these coral frags back onto natural reef enviros once they have grown to an appropriate size.  The corals outplanted for this study were grown in the Coral Restoration Foundation’s (CRF) coral nursery offshore of Tavernier, FL.  All outplanting, measuring and data collection was completed at Molasses Reef, a spur and groove reef offshore of Key Largo, FL.  Although very little A. cervicornis is found naturally at Molasses Reef today, skeletal remains and photo documentation suggests that the species was abundant until the mid 1980s.

A cervicornis is composed of low diversity, predominantly clonal populations of corals maintained by asexual fragmentation with clones shown to span distances as great as 30-50 m (Bowden-Kerby 2008).  The clonal nature of the species has major implications for the restoration of this threatened coral.  Because A. cervicornis fragments easily to create clonal populations, restoration is fairly simple but the highly clonal nature of the species might also present unforeseen challenges, over wide environmental gradients, as each genotype may be highly adapted to a narrow range of environmental tolerances.

Statistics still need to be run, but the data MRDF and CRF biologists collected in 2012 for the staghorn coral fragments outplanted are showing a distinct difference in growth rate amongst the three genotypes.  20 fragments of each genotype were planted.  The three different genotypes used in this study are denoted by K1, K2 and K3.  We had .02% mortality rate with only one coral fragment not surviving year 1 (K1).  All genotypes had the lowest average growth rate from August to September (tropical storm Isaac) and K1’s and K3’s both had the highest average growth rate from May to June.

	Average % growth in one year
K1	158
K2	220
K3	337

 

Data analysis of genotype growth at various depths and locations is underway to further investigate difference in environmental tolerances.

In November of 2012, we planted 18 new mangroves on the spit at MarineLab.  We used PVC that had previously been hammered in the ground but did not have a surviving mangrove.  Mangrove peat and decaying seagrass material was put into the PVC so that when propagules were placed within the PVC they were completely protected and at about mean high tide.

As background research varied and we do not have much information on the initial planting, we are experimenting to see if propagule germination status plays a role in survival and growth rate.  11 propagules collected came directly from a red mangrove while seven came from the water (4 of the 7 were floating horizontally and 3 of the 7 were floating vertically).

While we will need at least a year to draw any real conclusions, we are pleased that 17 of the 18 have survived since the initial planting.

Mangrove #	Collection Location	1/17/13	4/3/13
8	Tree	Propagule, no leaves	Propagule, 2 leaves
9	Floating horizontal	propagule with leaves	Propagule, 2 leaves
12	Floating vertical	Propagule, no leaves	Propagule, 4 leaves
19	Tree	Propagule, no leaves	Propagule, 2  leaves
20	Floating horizontal	Propagule, no leaves	Propagule, 4 leaves
21	Tree	Propagule, no leaves	Propagule, 2 leaves
22	Tree	Propagule, no leaves	Propagule, 2 leaves
28	Tree	Propagule with leaves	Propagule, 2 leaves
31	Floating horizontal	Alive but far down in PVC	Healthy propagule with 2 leaves but below the top of the PVC
33	Tree	EMPTY	EMPTY
34	Floating vertical	Propagule, no leaves	Has propagule but not healthy
39	Tree	Propagule with leaves	Propagule, 2 leaves
43	Floating horizontal	Propagule with leaves	Propagule, 2 leaves
48	Tree	Propagule with leaves	Propagule with 3 leaves
51	Tree	Propagule, no leaves	Propagule, 2 leaves
53	Floating vertical	Propagule, no leaves	Propagule but not healthy
61	Tree	Propagule with leaves	Propagule, 1 leaf
63	Tree	Propagule with leaves	Propagule, 2 leaves

 

January 2013

April 2013

Data collected for 60 staghorn coral fragments planted by CRF and MRDF biologists in January of 2012 and monitored monthly throughout the year is now being analyzed with the intent to publish.  Over a period of 15 months, we had a 98% survivorship rate  and an overall growth rate over the year of 2012 of 240%.  We are pleased with the success and will continue to monitor the site quarterly over the next year.  In the meantime, we are looking at the data to gain insight on growth rate of various genotypes grown in CRF’s nursery as well as influence of outplanting site choice- depth, location on spur, competition- on growth rates.

K2-5, March 2012

K2-5, March 2013

 

NOAA has partnered with MRDF in a new phytoplankton study.  Permits were approved last week and field work should get under way in the next month.  The study is looking at the implications of Ciguatera Fish Poisoning (CFP) at artificial reefs versus natural reefs.  The group of dinoflagellates responsible for CFP are benthic or epiphytic in nature.  Previous studies have shown an increase in the densities of these toxin producing species after coral bleaching events or other damage to coral reefs allowing new habitats to colonize.  This is of concern due to the increased frequency of coral bleaching events as well as the overall degradation of many of the worlds reefs.  One of the increasingly more frequent means to try and combat the loss of reef habitat is through the promotion of artificial reefs.  MRDF biologists will be deploying habitable material in healthy, impaired, and artificial reefs off of Key Largo.  Samples will be collected once a month by MRDF (and students when possible) which will then be sent to PMN for analysis.  In this way, we will quantify the accumulation of the toxigenic plankton and elucidate whether CFP is of increased concern in artificial reef environments.

In October of 2012, MarineLab received the permits necessary to set up permanent transects in Largo Sound for our seagrass surveys. (Largo Sound is a part of Pennekamp State Park).  Our data is now more comparable from survey to survey.  We plan on conducting our surveys on a quarterly basis in order to provide long term data to Seagrass Watch.

The ecological value of seagrasses have made the habitat a useful monitoring target for assessing environmental health and impacts on coastal systems.  Seagrass habitats provide sessile plants- individuals, populations and communities- which can all be easily measured.  Seagrasses also generally remain in place so that prevailing anthropogenic impacts can be monitored.  The picture below depicts the transect plot.

 

 

We are in the process of applying for permits to create two more sites within Largo Sound in order to provide replication.  KL1 is our current site.  For those of you that have been snorkeling in Largo Sound with us, KL1 and KL2 are North and South of Radabob Key; KL3 is Scotts Channel.

In 2012, MarineLab became a monitoring station for NOAA’s Phytoplankton Monitoring Network (PMN).  We tow for phytoplankton and monitor levels of target species at least twice a month.

Due to rich species diversity amongst plankton, the vast volume of water plankton inhabits, and because of plankton’s important role in the food chain, plankton is often included in monitoring and biodiversity assessments.

Phytoplankton are microscopic plants that form the base of the marine food chain. Though they are small, the energy they capture from the sun through photosynthesis helps to sustain almost all life in the ocean.  Because phytoplankton produce more than half of Earth’s oxygen supply, they are also important to life on land.

Pyrodinium bahamense and Striatella sp.

Phytoplankton play a critical role in the global carbon cycle.  Phytoplankton consume carbon dioxide from the ocean during photosynthesis and emit oxygen as a by-product.  As a result of photosynthesis, the oceans are a net sink (or consumer) for carbon dioxide. If the amount of phytoplankton in the global ocean is reduced as a result of climate change, for example, atmospheric carbon dioxide could increase.

The Phytoplankton Monitoring Network (PMN) was established as an outreach program for monitoring marine phytoplankton and harmful algal blooms (HABs).   A phytoplankton bloom has been defined as a “high concentration of phytoplankton in an area, caused by increased reproduction; [this] often produces discoloration of the water” (Garrison, 2005.) More generally, a bloom can be considered as a phytoplankton population explosion; blooms occur when sunlight and nutrients are readily available to the plants, and they grow and reproduce to a point where they are so dense that their presence changes the color of the water in which they live. Blooms can be quick events that begin and end within a few days or they may last several weeks. They can occur on a relatively small scale or cover hundreds of square kilometers of the ocean’s surface.

MarineLab instructors monitoring phytoplankton target species from Largo Sound samples

A phytoplankton bloom can be harmful in several ways.  Harmful algal blooms are referred to as HABs.  Some blooms can produce anoxic (without oxygen) or hypoxic (little oxygen) conditions in the water column.  This occurs when one or two species is the dominant organism in a bloom and blocks the sunlight from other organisms in the lower water column.  Other plankton begin to die and decompose.  Through the process of decomposition, oxygen is used up.  Fish die due to a lack of oxygen and decomposition continues.  Eventually, the massive blooms die as well,  removing any additional oxygen from the water column.

It is estimated that harmful algal blooms contribute to an estimated 100 million dollar loss per year in the US.  During harmful algal bloom events, there are closures of shellfish beds, lost production in fisheries, and reduction in tourism and associated service industries.  Public illness, medical treatment and advisories cost money.  Fisheries related businesses close and insurance and unemployment rates increase and public resource  are redirected to monitoring programs.

Human health can also be impacted from harmful algal blooms.  There are about 50 unknown species of phytoplankton that produce a toxin.  As the toxin moves through the food web, it bioaccumulates in the tissue of large fish and marine mammals.  Humans can contract illnesses from eating contaminated shellfish and fish.

The data PMN collects provides an important look into species composition and distribution in coastal waters. This is data which can lead researchers to identify areas to isolate for further investigation.

Since the late 90s, MarineLab has had an ongoing mangrove restoration project in the area of the “spit” on MRDF property.  In more recent years, MarineLab has been working on improving the mangrove site by monitoring growth more closely; the goal is to continue to plant mangroves while leaving as minimal a footprint as possible.  Red mangroves are the focus of the restoration project because the reds are the primary colonizers of mangrove habitats and their roots can be completely submerged in seawater at all times.  The protocol that MarineLab uses is the Riley Encased Method (REM).

The first principle of REM is the isolation of individual propagules inside encasements, in this case PVC, which creates an artificial environment favorable to early plant development.  The trees are protected from harsh environmental factors including debris, wind and wave activity, predation by macroinvertebrates and vertebrates, and unintentional damage from human interaction.  The effects of phototropism and protection from ultraviolet radiation result in accelerated plant growth.

Thin walled PVC pipes were cut lengthwise.  The longitudinal split is what allow the seedling to mature into a self-supporting tree.  Over time, the roots migrate down the encasement, the split widens and the tree will gain independence from the encasement.  Splitting of the encasement also provides an exchange of moisture with the surrounding environment.  The cut also permits the water level inside the PVC to rise and fall in accordance to tidal fluctuations and provides drainage for rain, waves or high tidal conditions.

The PVC pipes are pounded into the sediment and filled with decaying seagrass and mangrove peat to just below average water level.  Germinated, floating red mangrove propagules are collected from the water and then placed on top with some extra peat moss.  The peat moss is an important substrate for the mangroves and is gathered in an area where other mangroves grow in North Sound Creek.  Decaying seagrass provides nutrients as well as a substrate.  As the plant matures it should establish a dense foundation of prop roots and continue to develop independent of the encasement.

Over the years, we have had various levels of success with this project.  About 50% of propagules originally planted have survived and grown, some now breaking through the PVC encasement.  Additional propagules after been planted over the years.  We want to improve our restoration efforts by keeping better records of methodology, new plantings, growth, etc.  This way we will be able to plant more mangroves while minimizing our impact on the natural habitat.

Mangrove #2 in August, 2011

Mangrove #2 in October 2012 — notice the roots breaking through the PVC

Mangrove #44 October 2011

Mangrove #44 from October 2012 — notice the prop root growth over a year

Mangrove #65 – propagule planted in August of 2011

Mangrove #65 after 1 year growth – picture taken in October of 2012

Over the past few months, MarineLab has been assisting John McDermond, a graduate student at Nova Southeastern University, with his Masters project at Rodriguez Key.  MarineLab provides boat transport as well as data collection assistance in the water.  Below is a summary of John’s study:

“The purpose of this study is to examine population densities of the shallow water hermatypic finger coral Porites divaricata and to determine the mode and timing of its reproduction. Since P. divaricata is typically found in non-reefal habitats, the descriptive part of this study will provide valuable information about this under-studied species. Its patterns of reproduction will be compared to other poritids; its Caribbean congenor Porites porites in particular. The primary study site is Rodriguez Key, located 1.44 km off the east coast of Key Largo

 Population densities will be measured through the use of plastic quadrats laid along 2 transect lines of 30 meters in length.   Based on preliminary population measurements averaging 11.7 colonies per square meter, transects lines, each about 30 meters long, will be deployed across 2 different regions of similar depth at Rodriguez Key (Figure 1). They will be held down by placing two iron bars in the bottom, with a minimum of 10 randomly placed ½ by ½ meter quadrats on each line. The iron bar will be left in place to allow repetitive sampling at 4 times (approximately tri-monthly) over the year-long project. Corals will be directly counted, their major and minor axes measured, and number of branches and branch tips enumerated.”

Sarah assisting in Porites surveys

Porites divericata

data logger

Dr. Larry Brand’s lab at Univeristy of Miami’s RSMAS analyzed the water samples Sarah and Jessica collected in August as part of Dr. Brand’s ongoing Florida Bay cyanobacteria study.  The diagrams below show the results of overall abundance of algae (Chl) and abundance of cyanobacteria (PC), in addition to salinity levels from this particular sampling trip.

Since 2010, MarineLab has offered a Biodiversity Indexing Lab to AP students and/or returning students.  The lab builds on the ideas that are taught during our basic Invertebrate Diversity Lab – in addition to sorting out invertebrates from live rock, the advanced students compute Simpson’s Diversity Index.  Though the indexing lab is primarily used for educational purposes, we have been recording the final biodiversity index our students have computed each time in hopes that we will have some usable long term data.  See graph below.  As more groups participate in the lab, our data will become more valid.

Biodiversity, a term often misused and overused, is the diversity of living things.  It was originally thought that a higher diversity meant a more stable ecosystem, now diversity measurements are used to track changes within the environment.  An increase or decrease in biodiversity can indicate the extent and condition of a habitat and ecosystem health (Clarke and Warwich 2001).

Biological diversity can be measured in many different ways.  The two main factors taken into account when measuring diversity are richness and evenness.  Richness, the simplest measure of diversity, is a measure of the number of different kinds of organisms present in a particular area.  For example, species richness is the number of different species present.  Species richness does not take into account the abundance of each species.  It gives as much weight to the species with a single individual as to those with many individuals.  Evenness is a measure of the relative abundance of the different species making up the richness of an area.  If the number of individuals of each species found is the same, the evenness is high (Magurran 2004).

A diversity index is a mathematical measure of species diversity in a community.  There are over 60 different indices used in ecology including the Shannon Wiener Index (H), the Berger-Parker index (d), Hill’s N₁, Q-statistics, and Simpson’s Diversity Index, which is the index we will be utilizing for this lab.  Each of these indices has strengths and weaknesses.  For example, Simpson’s Index is weighted toward the abundance of the most common species rather than species richness (i.e. the addition of a rare species to a sample causes only small changes to value of D) whereas the Shannon-Wiener Index emphasizes richness.  An ideal index would demonstrate clearly and accurately between samples, not be greatly affected by differences in sample size and be relatively simple to calculate.  Biologists often use a combination of several indices to take advantage of the strengths of each and develop a more complete understanding of community structure (Magurran 2004).

Simpsons Diversity Index is a measure of diversity which takes into account both richness and evenness (Simpson 1949).  Simpsons Index (D) measures the probability that two individuals randomly selected from a sample will belong to the same species.  For example, the probability of two trees, picked at random from a tropical rainforest being of the same species would be relatively low, whereas in the boreal forest would be relatively high.

The value of D ranges between 0 and 1.  With this index, 0 represents infinite diversity and 1, no diversity.  The bigger the value of D, the lower the diversity.  As this is counterintuitive, D is often subtracted from 1 to give Simpsons Diversity Index (D_S).

Simpson’s Diversity Index (D_S) = 1-D

The value of this index also ranges between 0 and 1, but now, the greater the value, the greater the sample diversity.

Diversity indices have been a tool for comparing communities, however, important information is lost when species diversity is reduced to an index.  For example, a larger diversity index can reflect the influence of increased abundances of invasive or exotic species without conveying important information about the change in community integrity or function.  Very different community structures can produce the same diversity index.  Furthermore, ecologically unique communities are not necessarily diverse and would be lost if conservation decisions were made on the basis of diversity alone.

Simpson, E. H. 1949. Measurement of diversity. Nature 163:688

Clarke, KR and RM Warwick.  2001.  A further biodiversity index applicable to species lists: variation in taxonomic distinctness.  Marine Ecology Progress Series 216: 265-278.

 Magurran, A. E., 2004, Measuring biological diversity, Blackwell Publishing: Oxford, UK.256