They come in all different colors, shapes
and sizes…
You can have large and small sponges, shaped
as vases or baskets or even large barrel sponges.
They can be branching, they can be round,
they can be encrusting, they can be massive
or thin, so the variability of the body plan
is pretty amazing.
Many of us have used them to bathe or clean
with, and the most famous one is SpongeBob
SquarePants, a cartoon character who entertains
children from his pineapple in the sea.
But have you ever given sponges much thought?
The 500 million years of evolution, indicate
that they’re true survivors.
In recent years, researchers discovered that
sponges are one of the groups of marine animals
that produce the most bioactive compounds,
leading to many medicinal uses. These include
the development of drugs that treat viral
infections, other infectious diseases and
a variety of cancers.
there’s over 8,500 species of sponges that
are known. Sponges are found in all oceans
basins, from tropical to arctic. There’s
a few fresh water sponges so they are very
wide spread. Many tropical sponges can be
found on shallow reefs to deep reefs. Sponges
are animals, primitive and simple. They don’t
have true specialized or differentiated tissue
like a heart, or a brain or a liver. They
do have differentiated cells. Depending on
the type or class of sponge, the skeleton
can be made out of cilica or calcium carbonate.
So, most sponges have a cilica based skeleton
and these are in the form of, what’s called
spicules.
These spicules determine the consistency,
or feel, of a sponge.
You can go from very soft to very rock-like. People might learn
a little bit from sponges as to how do they survive
disturbances, changing climates. Who
do you want to go to when you run into trouble.
Well, it’s a group that’s been around
for a long period of time. And sponges fit
that bill.
What might sponge genomes tell us about long-term
survival? What other secrets might sponges
reveal?
Major funding for this program was provided
by the Batchelor Foundation, encouraging people
to preserve and protect America’s underwater
resources. And by Divers Direct/Emocean Sports
inspiring the pursuit of adventure and water
sports. And by the following In Memory of
Harriet Fagan, the Do Unto Others Trust, and
the Friends of Changing Seas.
The islands of the Bahamas.
A tropical paradise where sandy white beaches
lead to crystal clear waters that are home
to beautiful reefs and marine life.
The rich variety of sponges that thrive on
these reefs is of particular interest to Dr.
Joe Lopez, a professor at Nova Southeastern
University in Dania Beach, Florida.
I hope those sponges are ready for us.
Sponges’ role on a reef is variable and
complex. They can be food for some predators.
Some think, they are the glue of reefs because
they’re in many different parts of the reef.
They provide a three dimensional topography.
So they’re providing lots of new habitat
for other animals.
Sponges don’t have a digestive system. Instead
they are filter feeders that sift their food
out of the water.
They do this by creating a current through
their bodies with specialized cells. These
cells have a long tail and it beats causing
water to flow through these specialized canal
systems. These cells are able to pick off
particulates of food, which in most cases
they’re bacteria, plankton, dissolved organic
matter and that’s how they sustain themselves.
To demonstrate this powerful and efficient
filtering system, Joe injects harmless fluorescent
dye at the base of a sponge.
They’re creating this unidirectional flow
of water usually coming in through the sides
and then this canal system eventually empties
out into a bigger outgoing opening.
For his research, Joe is collecting tissue
samples from various types of sponges. His
goal is to compare samples of the same species
collected in different areas.
So we take a small section and they can cover
that cut and regrow. An important part of
sponges are the bacteria, and microbes that
live within that tissue because sometimes
that forms part of the actual body of certain
sponges called high microbial abundance sponges.
The microbial cells could make up 50% or more
of the whole sponge body so they’re highly
dependent on their microbial symbionts.
Joe is curious if these so-called microbiomes
of certain sponge species vary by location.
I’m part of a consortium of sponge biologists
who are now looking at various species of
sponge microbiomes. And this is part of a
broader earth microbiome project which is
very interesting. So we’ve been able to
apply high throughput DNA sequencing to multiple
species of sponges asking various types of
questions. Do they vary bio-geographically,
by host, or by season? It does seem to be
that specific sponge species have a specific
microbial community. We’d like to see how
much environment might affect the composition.
Preliminary analysis revealed distinct differences
in the microbiomes of the same species of
sponges collected near different islands in
the Bahamas. Samples collected off New Providence
Island, which is highly developed and home
to a relatively large human population, had
an approximately 10-fold higher abundance
of potentially pathogenic microbial groups
than those collected near Andros Island, which
is sparsely populated. These initial results
show that the proximity of human populations
can impact the microbial communities associated
with sponges.
Joe will also use the samples he’s collected
for more extensive genomic studies in the
future.
Got a couple species, well one that I’ve
never gotten before.
I’ve preserved specimens for long term DNA
use. So we’ll be able to isolate DNA from
the host as well as the microbial symbionts.
We’ll analyze the whole genome. These could
be part of the global invertebrate and genome
alliance which I helped found two years ago
at Nova Southeastern University. This stands
for GIGA. The goal of GIGA is to sequence
several types of genomes from multiple
species of invertebrates of which the sponges
belong. And we’ll see a lot of diversity
at the genomic level. Because of the
different habitats these sponges are found
in, the various forms or compounds they produce,
I think we’ll see some very interesting
insights once we read the DNA code of those
genomes.
Joe’s first trip to the Bahamas was 20 years
ago.
I came here as a student in the 90’s and
that’s what inspired me to go into marine
biology.
Let’s see what kind of air they gave us.
Hopefully good air.
Now he’s back for the first time in ten
years thanks to a partnership with the International
SeaKeepers Society.
Seakeepers was founded to get yacht owners
directly involved in ocean research and conservation
efforts. The most expensive part to doing
marine science research is getting out on
the water, is being able to be in the field,
collect samples, collect data, and get out
there long enough to really complete a full
project that can result in something significant.
And so one of the things that SeaKeepers is
currently doing, is to get more scientists
out in the field at no cost or very limited
cost to them.
One of the places Joe wanted to return to
on his trip is the community of Red Bays,
on the northern tip of Andros Island. Andros
is the largest, but also most sparsely developed
of all the Bahamian islands. Sometimes called
the sleeping giant, this island is famous
for its blue holes, traditional handicrafts,
and its sponge industry.
The sponge industry is still alive and kicking
in Red Bays. It’s a tradition. My forefathers,
they used to sponge. My granddaddy. When I
was a little boy he was always telling me
about sponges. Each family has one guy who
goes in the boat sponging.
Three different species of sponges are commercially
viable, called hard head, wool and grass sponges.
This is a hardhead. This is abundant. There’s
a lot of abundance. This is what we call a
wool. This is like the prize of sponges. This
one here to put about 22 to 23 on a strand
to get about 7, 6 dollars. But this one you
get about, on a nice solid one, this one is
really torn up inside, but you get about $20
for it. If the right buyer comes along.
Is there a certain season for sponges? No,
sponges is one season, all year. All year,
all year, all year for sponges. Leon is you’re
guy. Leon? Yeah. He’ll show you everything
man
Locals collect sponges on the shallow Great
Bahama Bank, on the west side of Andros island.
Well, not too many people have been studying
the genomics of these bath sponges so it might
be interesting to take a look at how they
compare with some other sponges and maybe
we can see how they produce this softer skeleton.
After sponges are cut from the bottom, they
are brought back to shore.
So we cut ‘em, take ‘em out, put ‘em
on the land, on the sand, preferably the sand
so that everything can just drain, drain down
to the sand. And sometime we walk, we walk
on ‘em to
speed up the process. And once all the barnacles
and everything get out of them they get light.
After some time on land, the sponges are taken
to a kraal in the ocean to soften up again.
The hardheads you can put them on the
shore today and you clean them tomorrow. But
the wool and the grass, they take like seven
days on the land and seven days in the kraal.
And you get the seven days in the kraal and
you beat them out and you tap them and tap
them and squeeze all the mud and everything
out of them and you throw them in the boat
and you’re good to go. For market.
Local spongers sell their product to a wholesaler
that ships them to markets all over the world.
Mostly the Greeks that buy sponges.
Sponging was once one of the country’s largest
fishing industries, until a disease outbreak
in the late 1930s wiped out the vast majority
of commercially viable sponges, putting many
Bahamians out of work.
Some people say it was a disease came about.
And there’s a bunch of different stories.
Some people say the Lord blew his breath on
it because some people was robbing the black
man. You know. There’s a bunch of different
stories. But now they’re back again, been
here for a little while. It just came back
to life in the early 60’s.
Today’s fishery is much smaller, but the
local spongers on Andros still take pride
in their work and quality product.
This is a beautiful one. That’s a grass.
That’s grass? Yeah, grass. That come off
the…That’s a roller.
They last a lifetime. The artificial ones
tear through. Sometimes you put some chemicals
on or soaps or whatever liquids and they tear
but if you get a piece of wool in the kitchen
or you’re using it on the bathroom it will
be like forever.
The only time sponges are able to move around
is in their larval stage, when they are ready
to hatch from their brooding chambers. But
how do these free swimming larvae know how
to orient themselves to find a good place
to settle and grow?
Sponges are known to possibly have this protein
which is involved in phototaxis and that means
that it allows the larvae to sense direction
and where light is being omitted. Most animals
use opsin, another protein as their photosensing
detector and molecule. Now sponges lack opsin,
but they do have crypto chrome so we’re
interested in looking in depth into how they
possibly use crypto chrome as the light sensor.
The challenge is collecting sponge larvae
at just the right time. In July 2015, Joe
and his former Ph.D. student Andia Chaves-Fonnegra
received word at their lab in Dania Beach,
Florida, that sponges on local reefs were
brooding, so they set out to collect samples.
It was great, lots of sponges. They have their
brooding chambers. They have their larvae.
It was successful, little chambers of larvae
inside the sponges, so that was good. These
are the brooding chambers. The white things
that we are seeing there are the eggs and
some of them are fertilized and they probably
will be in process of becoming a larvae and
that is what we want. So, this is a great
find, first time that we’ve found larvae.
They’ll have this black spot, and this black spot could
help them phototaxis towards the light, so
it's a kind of eye, and in this case it is
a non-neural eye, there’s no neurons or
advanced developed cells that would be involved
in vision.
Experts want to know how this fundamentally
different sensory system functions. To find
out, Joe has teamed up with collaborators
from the University of California.
We’re trying to keep some larvae live and
we're going to ship those out, others we're
going to keep for RNA analysis and DNA
analysis.
Together they plan to conduct genetic, physiological
and behavioral tests to determine if crypto-chrome
is indeed the light receptor in these sponges.
We are going to see if this molecule called
crypto-chrome is being expressed actively.
This is the first time we've looked
at it in this species and we can connect that
to the physiological studies if it's active
and expressed.
Understanding the function of this non-neural
eye will provide fundamental new insights
into sensory biology.
Until recently there was scientific consensus
that sponges were the first animals to branch
off the Animal Tree of Life.
Darwin first wrote in “The Origin of the
Species,” there is a tree that connects
all living organisms and people have been
trying to put together this tree for years.
So the tree of life is trying to show where
all these organisms are placed. So they’re
grouped according to similarities. So we have
reptiles distinct from mammals. Sponges are
generally placed at the base of the animal
part of the tree that then lead to more complex
animals.
The key thing is that everything is connected
and at the tips you have animals that
live today, and then there’s branches that
don’t really make it to the tips and those
would be extinct animals.
Dr. Joe Ryan is an assistant professor at
the Whitney Lab for Marine Bioscience in St.
Augustine, Florida, where he studies evolutionary
genomics.
Traditionally animals were grouped by their
morphological characteristics so animals like
primates who have relatively large brains
to their body size that would be used as a
character to unite primates. Sponges don’t
have very many characteristics that are similar
to other animals, so basically all other animals
are thought to be more closely related to
each other based on that morphological evidence.
And later with microscopy cell types were
used to kind of fine tune it. At the base
of the tree there was a single cell ancestor
to all animals and of course going from single
cells to a multicellular organism, is an increasing
complexity. So the next step would be an animal
that has multiple cells but doesn’t have
a nervous system, doesn’t have a musculature
system. So, it’s more of a passive type
animal and sponges - their morphology and their
cellular composition all fit well with this
idea of a simple to complex progression in
animal evolution.
As technology advanced, scientists also started
using DNA sequencing to help build the tree.
We’re all connected by DNA. Now if we can
read the sequence from all these organisms,
we can theoretically, put together a tree
of life of species that are existing now.
And we do that by counting the similarities
between the genes and what they show.
This has led to a surprising discovery that
has some experts casting doubt on the theory
that sponges were the first animals to branch
off the tree. In 2008, a group of international
scientists conducted genetic research suggesting
that ctenophores, also known as comb jellies,
are an older lineage.
It was a big discovery. The Ctenophores are
animals that live in saltwater.
Despite the fact that ctenophores look like
jellyfish, the two are not related.
There’s about 200 described species many
more that are known that haven’t been described
yet and they are found from the north pole
to the south pole, deep water, shallow water.
The initial research was received with skepticism
by many in the scientific community who felt
more data was needed.
I was one of those people who was in that
camp, once there’s more data this maybe
will change back to the way it was. But what
happened is the more data you throw at the
question, the stronger the result is.
Joe Ryan and his collaborators decided to
expand on the initial research findings.
We sequenced the genome of the warty comb
jelly to say okay what happens when we re-run
these analyses but with a complete set of
data and the position of Ctenophores as the
sister group to the rest of animals held.
And then we also started asking, well what
if we look at different ways of looking at
this data do we get a different answer? And
that also came out in favor of the Ctenophores
as the sister group. So we had independent
evidence and we confirmed some existing ideas.
But if Ctenaphores did indeed branch off the
animal tree of life first, several long-held
theories about the evolution of animal traits
are thrown into disarray.
Historically, it was thought that simpler
animals like sponges, which do not have muscles
or a nervous system, were the building blocks
for more complex animals higher up the tree.
Ctenophores, however, do have a nervous system
and muscles, so if they came first how does
that explain the lack of these features in
sponges? Scientists have come up with two
hypotheses – either ctenophores developed
a nervous system independently from the rest
of the animals, or sponges lost theirs.
Either of these are really difficult to understand
because we think our nervous system is the
greatest thing in the world, right? So, if
the ancestor had it. tjem how is it lost in sponges?
How could an animal lose a nervous system?
And also it’s incredibly complex, the nervous
system, how could it independently happen
twice?
There is precedent for organs evolving more
than once. Eyes, for example, are known to
have evolved several times in different species.
But there also is precedent for animals losing
seemingly vital organs.
There are cnidarian worms that are related
to jellyfish and they’ve lost their nervous
system. Perhaps sponges started off as these
filter feeders that live in the bottom of
the ocean and having a nervous system was
a high cost, from a metabolism point of view.
If you’re trading off between filtering
and sensing your environment with neural cells,
it becomes better to invest more energy into
the filtering.
Further research is needed to settle the debate
over who branched off first from the animal
tree of life.
There’s so much data out there with this
advanced sequencing that it’s going to take
time to clearly make sense of it, but I think
the final word is not out. I mean I think
we  still need to look at all the data together.
I believe in total data sets. Now the hard
thing about working with these very old lineages
is this is very deep time, 600 million years,
so it’s tough.
I think it’s important in science to explore
all the possibilities. I’m open to all the
possibilities, right? You have to be.
Major funding for this program was provided
by the Batchelor Foundation, encouraging people
to preserve and protect America’s underwater
resources. And by Divers Direct/Emocean Sports
inspiring the pursuit of adventure and water
sports. And by the following In Memory of
Harriet Fagan, the Do Unto Others Trust, and
the Friends of Changing Seas.
