Embrace the Gulf 2020 – the cephalopods

Embrace the Gulf 2020 – the cephalopods

For many of the blogs we have posted on marine life of the Gulf of Mexico I have used the term “amazing” – but these cephalopods are truly amazing.  There have been numerous nature programs featuring not just marine invertebrates but rather highlighting the cephalopods specifically.  We have been amazed by their looks, their colors, their intelligence, and their ferocity.  They are the animals of ancient mariner legends – the “kraken”.

These are not your typical mollusk. The elongated body and lack of external shell changes everything for cephalopods.
Photo: California Sea Grant

But for us who just visit the beach to play and walk – we rarely see them.  They are quite common.  The squid are almost transparent in the water column as they swim and usually run deep until nighttime.  The only ones I have ever encountered were hauled up in shrimp trawls – but they are usually hauled up each time, and sometimes in great numbers.  Octopus are more nighttime roamers as well.  I have occasionally seen them diving during daylight hours, but they are very secretive and well camouflaged.  I have found cephalopods both in the Gulf and within the estuaries – again, they are more common than we think.

 

A study conducted in the 1950s logged 42 species within the Gulf of Mexico.  Many of them live in the open sea and at depths of 350-500 feet.  There are actually four types of cephalopods – the octopus and squid we know, the cuttlefish and nautilus less so because they are not common in the Gulf region.

 

They are mollusk but differ from their snail and clam cousins in that they have very little, if any shell.  The nautilus is an ancient member of this group and still possess an external shell.  However, it is chambered and can be filled with gas like a hot air balloon allowing the nautilus to hover off the seafloor – something their snail/clam cousins can only dream about.

 

The squid and cuttlefish have reduced their shell to a surfboard looking structure that is found internally, serving almost like backbone.  It allows them some rigidity in the water column, and they can grow to greater size.  Actually, the squid are the largest invertebrates on the planet, with the “giant squid” (Architeuthus) reaching lengths of 50 feet or more.

The octopus differs from the squid in that it lacks a shell all together. Thus, it is smaller and lives on the ocean floor.
Photo: University of South Florida

The octopus lack a shell all together.  Without this rigid bone within, they cannot reach the great size of the giant squid – so giant octopus are legend.  However, there is a large one that grows in the Pacific that has reached lengths of 30 feet and over 500 pounds – big enough!

 

The lack of a shell means they must defend themselves in other ways.  One is speed.  With no heavy shell holding you down, high speed can be achieved.  Again, squid are some of the fastest invertebrates in the ocean – being clocked at 16 mph.  This may not outrun some of the faster fish and marine mammals, and many fall victim to them.  Birds are known to dive down and eat large numbers of them.  But they can counter this by having chromatophores.  These are cells within the skin filled with colored pigments that they can control using muscles.  This allows them to change color and hide.  And their ability to change color is unmatched in the animal kingdom.  I recommend you find some video online of the color change (particularly of the cuttlefish) and you will be amazed.  Yes… amazed.

The chromatophores allow the cephalopods to change colors and patterns to blend in.
Photo: California Sea Grant

To control such color, they must have a more developed brain than their snail/clam cousins – and they do.  The large brain encircles their esophagus and not only be used to ascertain the colors of the environment (and how to blend in) but also has the capability of learning and memory.  The octopus in particular has been able to solves some basic problems – to escape, or get food from a closed jar, for example.  Many of these chromatophores possess iridocytes – cells that act has mirrors and enhance the colors – again, amazing to watch.

 

All cephalopods are carnivorous and hunt their prey using their well-developed vision.  Squid prefer fish and pelagic shrimp.  Octopus are inclined to grab crustaceans and other mollusk – though they will grab a fish when the opportunity presents itself.  Cephalopods hunt with their tentacles – which are at the “head end” of the body.  The squid possess eight smaller arms and two longer tentacles.  Each have a series of sucker cups and hooks to grab the prey.  They keep their tentacles close to their bodies and, when within range, quickly extend them grabbing the fish and bringing back to the mouth where a sharp parrot-like beak is found.  They bite chunks of flesh off and some have seen them bite the head off a mackerel.  I was bitten on the hand by a squid once – one of the more painful bites I have ever had.

The extended tentacles of this squid can be seen in this image.
Photo: NOAA

The octopus does not have the two long tentacles – rather only the eight arms (hence its name).  They move with stealth and camouflage (thanks to the chromatophores) sneaking up on their prey – or lying in wait for it to come close.  Here things change a bit.  Octopus possess a neurotoxin similar to the one found in puffer fish.  They can bite the crab – inject the venom – which includes digestive enzymes similar to rattlesnakes and spiders – and ingest the body of the semi-digested prey after it dies.  They can drill holes into mollusk shells and inject the venom within.  Most will give a painful bite but there is one in the Indo-Pacific (the blue-ringed octopus) whose venom is potent enough to kill humans.

 

Making new octopus and squids involves the production of eggs.  The male will deposit a sac of sperm called a spermatophore into the body of the female.  She will then fertilize her eggs and excrete them in finger like projections that do not have hard shells.  Squid usually die afterwards.  Octopus will remain with the eggs – oxygenating and protecting them until they hatch.  At which time they will die.

Though we have a variety of cephalopods near shore – the real grandeur is offshore.  Out there are numerous species of bioluminescent cephalopods – most living at 500 feet during the day and coming within 300 feet at night.  Many swim, while some float, others have developed a type of buoyant case they can carry their eggs in.  Far too much to go into in a blog such as this one.  I recommend you do a little searching and learn more about these amazing animals.

 

Enjoy the Gulf!

Embrace the Gulf 2020 – the bivalves

Embrace the Gulf 2020 – the bivalves

This is a good name for this group.  They are mollusk that have two shells.  They tried “univalve” with the snails and slugs, but that never caught on – gastropods it is for them.  The bivalves are an interesting, and successful, group. They have taken the shell for protection idea to the limit – they are COMPLETELY covered with shell.  No predators… no way.  But they do have predators – we will talk more on that.

 

An assortment of bivalves, mostly bay scallop.
Photo: Florida Department of Environmental Protection.

As you might expect, with the increase in shell there is a decrease in locomotion – as a matter of fact, many species do not move at all (they are sessile).  But in a sense, they do not care.  They are completely covered and protected.  Again, we will talk more about how well that works.

 

The two shells (valves) are connected on the dorsal side of the animal and hinged together by a ligament.  Their bodies are laterally compressed to fit into a shell that is aerodynamic for burrowing through soft muds and sands.  Their “heads” are greatly reduced (even missing in some) but they do have a sensory system.  Along the edge of the mantle chemoreceptive cells (smell and taste) can be found and many have small ocelli, which can detect light.  The scallops take it a step further by having actually eyes – but they do live on the surface and they do move around – so they are needed.

 

The shells are hinged together at the umbo with “teeth like structures and the shells open and close using a pair of adductor muscles.  Many shells found on the beach will have “scars” which are the point of contact for these muscles.  They range is size from the small seed clams (2mm – 0.08”) to the giant clam of the Indo-Pacific (1m – 3.4 ft) and 2500 lbs.!  Most Gulf bivalves are more modest in size.

 

Being slow burrowing benthic animals, sand and mud can become a problem when feeding and breathing.  In response, many bivalves have developed modified gills to help remove this debris, and many actually remove organic particles using it as a source of food.  Many others will fuse their mantle to the shell not allowing sediment to enter.  But some still does and, if not removed, will be covered by a layer of nacreous material forming pearls.  All bivalves can produce pearls.  Only those with large amounts of nacreous material produce commercially valuable ones.

Coquina are a common burrowing clam found along our beaches.
Photo: Flickr

Another feature is the large foot, used for digging a burrowing in the more primitive forms.  It is the foot we eat when we eat clams.  They can turn their bodies towards the substrate, begin digging with their foot but also using their excurrent from breathing to form a sort of jet to help move and loosen the sand as they go – very similar to the way we set pilings for piers and bridges today.

 

These are the earliest forms of bivalves – the burrowers.  Most are known as clams and most live where the sediment is soft.  Located near their foot is a sense organ called a statocyst that lets them know their orientation in the environment.  Most have their mantles fused to their shells so sand cannot enter the empty spaces in the body.  To channel water to the gills, they have developed tubes called siphons which act as snorkels.  Most burrow only a few inches, some burrow very deep and they are even more streamlined and elongated.

 

Some have evolved to burrow into harder material such as coral or wood.  One of the more common ones is an animal called a shipworm.  Called this by mariners because of the tunnels they dig throughout the hulls of wooden ships, they are not worms but a type of clam that have learned to burrow through the wood consuming the sawdust of their actions.  They have very reduced shells and a very long foot.

This cluster of green mussels occupies space that could be occupied by bivavles like osyters.

Other bivalves secrete a fibrous thread from their foot that is used to grab, hold, and sometimes pull the animal along.  These are called byssal threads.  Many will secrete hundreds of these, allow them to “tan” or dry, reduce their foot, and now are attached by these threads.  The most famous of this group are the mussels.  Mussels are a popular seafood product and are grown commercial having them attach to ropes hanging in the water.

 

Another method of attachment is to literally cement your self to the bottom.  Those bivalves who do this will usually lay on their side when they first settle out from their larval stage and attach using a fluid produced by the animal.  This fluid eventually cements them to the bottom and the shell attached is usually longer than the other side, which is facing the environment.  The most famous of these are the oysters.  Oysters basically have lost both their “head” and the foot found in other bivalves.  These sessile bivalves are very dependent on tides and currents to help clear waste and mud from their bodies.

Oysters are a VERY popular seafood product along the Gulf coast.
Photo: Rick O’Connor

Then there are the bivalves who actually live on the bottom – not attached – and are able to move, or even swim.  Most of these have well developed tentacles and ocelli to detect danger in the environment and some, like the scallops, can actually “clap their shells together” to create a jet current and swim.  This is usually done when they detect danger, such as a starfish, and they have been known to swim up to three feet.  Some will use this jet as a means of digging a depression in the sand they can settle in.  In this group, the adductor has been reduced from two (the number usually found in bivalves) to one, and the foot is completely gone.

 

As you might guess, reproduction is external in this group.  Most have male and female members but some species (such as scallops and shipworms) are hermaphroditic.  The gametes are released externally at the same time in an event called a mass spawning.  To trigger when this should happen, the bivalves pay attention to water temperature, tides, and pheromones released by the opposite sex or by the release of the gametes themselves.

Scallop life cycle.
Image: University of Florida IFAS

The fertilized eggs quickly develop into a planktonic larva known as a veliger. This veliger is ciliated and can swim with the current to find a suitable settling spot.  Some species have long lived veliger stages.  Oysters are such and the dispersal of their veliger can travel as far as 800 miles!  Once the larval stage ends, they settle as “spat” (baby shelled bivalves) on the substrate and begin their lives.  Some species (such as scallop) only live for a year or two.  Others can live up to 10 years.

 

As a group, bivalves are filter feeders, filtering organic particles and phytoplankton as small as 1 micron (1/1,000,000-m… VERY small).  In doing this they do an excellent job of increasing water clarity which benefits many other creatures in the community.  As a matter of fact, many could not survive without this “eco-service” and the loss of bivalves has triggered the loss of both habitat and species in the Gulf region.  Restoration efforts (particularly with oysters) is as much for the enhancement of the environment and diversity as it is for the commercial value of the oyster.

 

Now… predators… yes, they have many.  Though they have completely covered their bodies with shell, there are many animals that have learned to “get in there”.  Starfish and octopus are famous for their abilities to open tightly closed shells.  Rays, some fish, and some turtles and birds have modified teeth (or bills) to crush the shell or cut the adductor muscle.  Sea otters have learned the trick to crush them with rocks and some local shorebirds will drop them on roads and cars trying to access them.  And then there are humans.  We steam them to open the shell and cut their adductor muscle to reach the sweet meat inside.

It is a fascinating group – and a commercial valuable one as well.  Lots of bivalves are consumed in some form or fashion worldwide.  Take some time at the beach to collect their shells as enjoy the great diversity and design within this group.  EMBRACE THE GULF!

Embrace the Gulf 2020 – marine snails and slugs

Embrace the Gulf 2020 – marine snails and slugs

One of the largest groups of invertebrates in the Gulf are the Mollusk… what many call “seashells”.  Shell collecting has been popular for centuries and, in times past, there were large shows where shells from around the world were traded.  Almost everyone who visits the beach is attracted to, and must take home, a seashell to remind them of the peace beaches give us.  Many are absolutely beautiful, and you wonder how such small simple creatures can create such beauty.

One of the more beautiful shells from the sea – the nautilus.
Photo: Wikipedia

Well, first – not all mollusk are small.  There are cephalopods that rival the size of some sharks and even whales.

Second, many are not that simple either.  Some cephalopods are quite intelligent and have shown they can solve problems to reach their food.

But beautiful they are, and the colors and shapes are controlled by their DNA.  Just amazing.

 

There are possibly as many as 150,000 different species of mollusks.  These species are divided into 8-9 classes (depending which book you read) but for this series on Embracing the Gulf we will focus on only three.  First up – the snails (Class Gastropoda).

 

There are an estimated 60,000 – 80,000 species of gastropods, second only to the insects.  They are typically called snails and slugs and are different in that they produce a single coiled shell.  The shell is made of calcium carbonate (limestone) and is excreted from tissue called the mantle.  It covers their body and continues to grow as they do.  The shell coils around a linear piece of shell called the columella.  Most coil to the right, but some to the left – sort of like right and left-handed people.  There is an opening in the shell where the snail can extend much of its body – this is called the aperture – and some species can close this off with a bony plate called an operculum when they are inside.  Some snail shells have a thin extension near the head that protects the siphon – a tube that acts like a snorkel drawing water in and out of the body.

The black siphon can be seen in this crown conch crawling across the sand.
Photo: Franklin County Extension.

They have pretty good eyes and excellent sense of smell.  They possess antenna, which can be tactile or sense chemicals in the water (smelling) to help provide information to a simple brain.

 

They are slow – everyone knowns this – but they really don’t care.  Their thick calcium carbonate shells protect them from most predators in the sea… but not all.

 

Their cousins the slugs either lack the shell completely, or they have a remnant of it internally.  You would think “what is the point of an internal shell?” – good question.  But the slugs have another defense – they are poisonous.  Venomous and poisonous are two different things.  Being poisonous means you have a form of toxin within your body tissue.  If a predator eats you – they will get very sick, maybe die.  But you die as well, so… Not too worry, poisonous slugs are brightly colored – a universally understood signal to all predators.

 

There is one venomous snail – the cone snail, of which we have about five species in the Gulf.  They possess a stylet at the tip of their siphon (similar to the worms we have been writing about) which they can use as a dart for prey such as fish.  Many gastropods are carnivores, but some are herbivores, and some are scavengers.

Many shells are found on the beach as fragments. Here you see the fragment of a Florida Fighting Conch.
Photo: Rick O’Connor

Most have separate sexes and exchange gametes in a sack called a spermatophore.  Fertilized eggs are often encased in structures that resemble clusters, or chains, of plastic.  These are deposited on the seafloor and the young are born with their shell ready for life.

 

This group is not as popular as a food item as other mollusk but there are some.  The Queen Conch is probably of the most famous of the edible snails, and escargot are typically land snails.  I am not aware of any edible slugs… and that is good thing.

 

Some of the more common snails you will find along our portion of the Gulf of Mexico are:

 

Crown Conch                   Olive                                  Murex                 Banded Tulip

Whelks                              Cowries                             Bonnets              Cerith

Slippers                              Moon                                Oyster Drills       Bubble

 

The most encountered slug is the sea hare.

A common sea slug found along panhandle beaches – the sea hare.

I hope you get a chance to do some shelling – I hope you find some complete ones.  It is addictive!

Hurricane Season has arrived

Hurricane Season has arrived

The lineup of 2020 tropical storm names. Tropical storm “Cristobal” is currently headed towards the northern Gulf of Mexico. Photo credit: The Weather Channel

This past March, many people spoke about sensing a sort of free-floating anxiety, waiting for potential disaster to land at their doorstep. The unknowns we faced as COVID-19 cases increased in the United States were not quite like anything we’d previously experienced, although it felt comparable to knowing a hurricane was about to make landfall. After this virus, perhaps, a hurricane seems like a relief—at least we know what to expect and approximately where the most damage will occur. However, big tropical storms carry with them their own set of unpredictable factors like direction and strength at landfall. But the storm-hardiness of our homes, our tree choices, smart evacuation plans—these we can control. Well-thought out precautions can make the difference between getting right back on your feet after a storm and losing almost everything.

Aluminum shutters are one of the many preventative measures Florida homeowners can include in their hurricane preparedness.
Photo: Carrie Stevenson, UF IFAS Extension

No matter how well you have planned for a hurricane, unexpected issues always come up. However, being ready can cut down on the fear and worry.
A few of those preparedness factors include:
* An evacuation plan
* A hurricane kit
* Home wind mitigation techniques
* Tree evaluation
* Wind/flood insurance
I will discuss each of these topics in depth over the next few weeks. Particularly if you are new to the area or never experienced a hurricane, be sure to review good readiness websites, check out these apps, and see which tips might be the most useful to you and your family as we enter the already-active 2020 hurricane season.

The Connection Between Nitrogen and Water Quality

The Connection Between Nitrogen and Water Quality

Recently there was a report of high fecal bacteria in a portion of Perdido Bay.  I received a few concerned emails about the possible source.  Follow up sampling from several agencies in both Florida and Alabama confirmed the bacteria was there, the levels were below both federal and state guidelines (so no advisory issued), and a small algal bloom was also found.  It was thought the cause was excessive nutrients and lack of rain.

 

We hear this a lot.

Excessive nutrients and poor water quality.

What is the connection?

Many people understand the connection, others understand some of it, others still do not understand it.  UF IFAS has a program called LAKEWATCH where citizen science volunteers monitor nutrients in some of lakes and estuaries within the state.  Here in Escambia County, we have six such volunteers.  Some of the six bodies of water have been monitored for many years, others are just starting now, but the data we have shows some interesting issues – many have problems with nitrogen.  Let’s look closer.

The nitrogen cycle.
Image: University of Florida IFAS

We have all heard of nitrogen.  Many will remember from school that it makes up 78% of the air we breathe.  In the atmosphere nitrogen is present as a gas (N­2).  It is very common element found in living creatures – as a matter of fact, we need it.  Nitrogen is used to build amnio acids – which builds proteins – which is needed to produce tissue, bone, blood, and more.  it is one of the elements found in our DNA and can be used to produce energy.  However, it cannot do these in the atmospheric gas form (N2) – it needs to be “converted” or “fixed”.

 

One method of conversion is the weather.  Nitrogen gas are two molecules of nitrogen held together by strong chemical bonds (N2).  However, lightning provides enough energy to separate N2 and oxidize it with oxygen in the atmosphere forming nitrogen dioxide (NO2).  This NO2 combines with water in the atmosphere to form nitric acid (HNO3).  Which can form nitrates (NO3) with the release of the hydrogen and nitrate (NO3) is usable by plants as a fertilizer… a needed nutrient.

 

But much of the usable nitrates do not come from the atmospheric “fixing” of nitrogen via lightning.  It comes from biological “fixing” from microbes.  Atmospheric nitrogen can be “fixed” into ammonia (NH3) by bacteria.  Another group of bacteria can convert ammonia into nitrite (NO2), and a third group can convert it from nitrite to the usable form we know as nitrate (NO3).  Ammonia can also be found in the environment as a waste product of life.  As we use nitrogen within bodies it can be converted into ammonia – which can be toxic to us.  Our bodies remove this ammonia via urine, and many times we can smell this when we go to the restroom.  Nitrogen fixing bacteria can convert this ammonia to nitrites as well and complete the nitrogen cycle.

 

Once nitrogen has been fixed to the usable nitrate it can be taken up by plants and used within.  Animals obtain their needed nitrogen by eating the plants or eating the animals that ate the plants.  In both cases, nitrogen is used for protein synthesis in our bodies and unused nitrogen is released into the environment to continue the cycle.

 

So, what is the connection to water quality?

You might think that excessive nitrogen (nutrients) in the water would be a good thing.  Released ammonia, though toxic, could be “fixed” into nitrite and eventually nitrate and recycled back into life.  And you would right.  Excessive amounts of ammonia though, may not be converted quick enough and a toxic state could occur.  We see this in aquaculture ponds and home aquaria a lot.

Members of the herring family are ones who are most often found during a fish kill triggered by hypoxia.
Photo: Madeline

But what about excessive nitrates? Shouldn’t that be good for the plants?

The concept makes sense, but what we see with increase plant growth in aquatic systems is problematic.  Excessive plant growth can cause several problems.

1)      Too much plant growth at the surface (algae, leafy vegetated material) can block sunlight to the other plants living on the bottom of the waterway.  This can cause die off of those plants and a mucky bottom – but there is more.

2)      Excessive plant growth at the surface and the middle of the water column can slow water flow.  Reduced water flow can negatively impact feeding and reproductive methods for some members of the community, cause stagnation, and decrease dissolved oxygen – but there is more.

3)      Plants produce oxygen, which is a good thing, so more plants are better right?  Well, they do produce oxygen when the sun is up.  When it sets, they begin to respirate just as the animals do.  Here excessive plants can remove large amounts of dissolved oxygen (DO) in the water column at night.  If the DO levels reach 3.0 µg/L many aquatic organisms begin to stress. We say the water is hypoxic (oxygen starving).  When a system becomes hypoxic the animals will (a) come to the surface gasping, (b) some even approach the beach (the famous crab jubilee of Mobile Bay), (c) leave the water body for more open water, (d) die (a fish kill).  This is in fact what we call a dead zone. Not always is everything dead, in many cases there is not much alive left – they have moved elsewhere so we say the bottom is “dead”. Here is something else… as the dead fish and (eventually) dead plants settle to the bottom they are decomposed by bacteria.  This decomposition process requires dissolved oxygen – you guessed it – the DO drops even further enhancing the problem.  In some cases, the DO may drop to 0.0 µg/L.  We say the water is now anoxic (NO oxygen).  I have only seen this twice.  Once in Mobile Bay, and once in Bayou Texar.  But I am sure it happens more often.  The local environment can enhance (or even cause) this problem as well.  Warm water holds less oxygen and much of the oxygen dissolved in water comes from the atmosphere – by way of wave action.  So, on hot summer days when the wind is not moving much, and excessive nutrients (nitrogen) is entering the water, you have the perfect storm for a DO problem and possible fish kill.

4)      Oh, and there is one other issue… some of the algae that produces these blooms release toxins into the water as a defense.  These are known as harmful algal blooms (HABs).  Red tide is one of the more famous ones, but blue-green blooms are becoming more familiar.  So now you have a possible hypoxic situation with additional toxins in the water that can trigger large fish kills.  Some of these HABs situations have killed marine mammals and sea turtles as well.

Though this process can occur naturally (and does) excessive nutrients certainly enhance them, and in some cases, initiate them.  So, too much nitrogen in the system can be bad.

 

So, what does the LAKEWATCH data tell us about the Pensacola Bay system?

Well, first, we have not had volunteers on all bodies of water for the same amount of time.  We currently have volunteers monitoring (1) northern Pensacola Bay, (2) Bayou Texar, (3) Bayou Chico, (4) Bayou Grande, (5) Big Lagoon, and (6) lower Perdido Bay.  Pensacola Bay has JUST started, and Big Lagoon has not even started yet (COVID-19 issues) – so we only have data from the other four.  Bayou Texar has the longest sample period at 13 years.

Lakewatch is a citizen science volunteer supported by the University of Florida IFAS

Second, this program does not sample for just nitrogen, but another key nutrient as well – phosphorus.  When you look at a bag of fertilizer you will see a series of numbers looking like:  30-28-14.  This would be nitrogen, phosphorus, and potassium.  People adding fertilizer to their lawns should know which nutrient they need the most and can by a fertilizer with a numerical concentration that is best for their lawn.  You can have your soil tested at the county extension office.  But the point here is that there is more than nitrogen to look at and, as we have learned, more than one form of nitrogen out there.  So, what we do at LAKEWATCH is monitor for total nitrogen (TN) and total phosphorus (TP).

 

Another parameter monitored is total chlorophyll a (TC).  The idea is… if there are excessive amounts of nutrients in the water there will be excessive amounts of algae.  You could collect a sample of water and count the number of algal cells in the water – but another way is to measure the amount of chlorophyll in the water as a proxy for the amount of algae.  Chlorophyll, of course, is the compound within plants that allows photosynthesis to happen.  There is a chemical process used to release the chlorophyll within the cells and you can then use an instrument to measure the amount of chlorophyll in the water.

 

LAKEWATCH volunteers also monitor water clarity.  It is true that clarity can be impacted by sediments in the water as much as an algal bloom, but anything that contributes to less sunlight reaching the bottom can be problematic for some bodies of water.  This is done by lowering a disk into the water and measuring the depth at which it “disappears”.

 

For those not familiar with the term salinity, it is the measure of the amount of dissolved solids in the water – what most people say, “how salty is it?”.  For reference, the Gulf of Mexico is usually around

35‰, most open estuaries are between 20-30‰.

 

Below is a table of the LAKEWATCH data we have as of the spring 2020.

 

Year of Sampling Body of Water Total Phosphorus (µg/L) Total Nitrogen (µg/L) Total Chlorophyll (µg/L) Water Clarity (feet) Salinity (‰)
2014 – 2018 Bayou Chico 20-30 350 – 600 10 – 30 2.6 – 4.2 7.0 – 8.2
2012 – 2017 Bayou Grande 16 – 19 320 – 340 5 -6 4.0 – 5.2 17 – 18
2007 – 2018 Bayou Texar 17 – 18 600 – 800 6 – 8 3.4 – 3.8 8 – 10
2014 – 2018 Lower Perdido 15 -16 350 – 360 5 -6 5.3 – 6.1 13 -14
STATE AVG. (includes lakes) 25.0 309 3.7    

 

There are a couple of things that stand out right away

(keep in mind some water bodies have not been monitored very long by LAKEWATCH).

 

1)      Phosphorus is not as big a problem in our part of the state.  In the peninsula part of Florida there is a lot of phosphorus in the sediments and much of it is mined.  You can see this in the average value for the state.  Actually, because of this, many of the central and south Florida lakes are naturally high in phosphorus and this is not considered “polluted”.  All that said, there are higher levels of phosphorus in Bayou Chico.  Which is interesting.  More on solutions in a moment.

2)      We have a lot of nitrogen in our waters.  Bayou Texar in particular is much higher than the state average.  More on this in a moment.

3)      We have a little more chlorophyll than the state average, but not alarming.

4)      Bayou Grande and lower Perdido are clearer than Bayou’s Texar and Chico.

5)      All these bodies of water are less than 20‰.  More on this as well.

 

So, comments…

 

1)      We already discussed the phosphorus issue (or non-issue), but what about Bayou Chico?  Phosphorus is NOT introduced to the system from the atmosphere as nitrogen is – rather, it comes from the sediments.  High levels of TP would suggest high levels of sediments in the water column (the water clarity data supports this) – which suggest high levels of run-off.  The watershed for Bayou Chico is highly urbanized and run-off has historically been a problem.

2)      Nitrogen can come from many sources, but when numbers get high – many will hypothesize they are most likely from lawn run-off (fertilizers), or sewage (septic leakage, sanitary sewage overflows, animal waste).  There are certainly other possibilities, but this is where most resource managers and agencies begin.

3)      Elevated chlorophyll indicates elevated primary production.  This is not unusual for an estuary.  They are known for their high productivity.  Bayou Chico seems have more algae than the others.  Most probably due to the increase levels of nutrients entering the watershed.

4)      Bayou Grande and lower Perdido Bay have better water clarity than Bayou’s Chico and Texar.  Though all four bodies of water have significant coastal and watershed development, Bayou’s Chico and Texar and completely developed as well as their “feeder creeks”.  Again, indication of a run-off problem.

5)      All four bodies of water have several sources of freshwater input as well as stormwater run-off that has contributed to the lower salinities found here.  It is possible that the salinities here were less than 20‰ prior to heavy development.

Possible Solutions….

There is a common theme with each of these – stormwater run-off.  Rain that historically fell on the land and percolated into the ground water, now flows off impervious surfaces (streets, driveways, parking lots, even buildings) into drainage pipes and discharges into the waterways.  This stormwater carries with it much more than just fertilizers and animal waste, it carries pesticides, oil, grease, solid waste, leaf litter, and much more.

 

How do you reduce stormwater?

Well, there is not much you can do with impervious surfaces now, but the community should consider alternative materials and plans for future development – what we call “Green Infrastructure.  Green roofs, pervious streets and parking lots, there are a lot of methods that have been developed to help reduce this problem.

 

Another consideration is Florida Friendly Landscaping.  This is landscaping with native plants that require little (or no) water and fertilizer.  It also includes plants that can slow run-off and capture nutrients before they reach the waterways and methods of trapping run-off onto your property.

 

If you happen to live along a waterway, you might consider landscaping your property by restoring some of the natural vegetation along the shoreline – what we call a living shoreline.  Studies have shown that these coastal plants can remove a significant amount of nitrogen from the run-off of your property as well as reduce coastal erosion and enhance fisheries by providing habitat.

Closed due to bacteria.
Photo: Rick O’Connor

What about sewage issues?

Unfortunately, most septic systems were not designed to remove nitrogen – so leaks occur and will continue.  The only options you have there are (a) maintain your septic by pumping once every five years, (b) consider taping into a nearby sewage line.

Sewers systems are not without their problems.  Sanitary sewage overflows do occur and can increase nitrogen in waterways.  These are usually caused by cracks in old lines (which need to be replaced), are because we flush things down drains that eventually “clog the arties” and cause overflows.  Things such as “flushable wipes”, which are flushable – they go down the drains – but they do not breakdown as toilet paper does and clog lines.  Cooking grease and oil, and even milk have been known to clog systems.

 

Our LAKEWATCH volunteers will continue to sample three stations in each of their bodies of water.  We are looking for a volunteer to monitor Escambia Bay.  If interested contact me.

 

If you are interested learning more about green infrastructure, Florida Friendly Landscaping, or living shorelines lines contact your county extension office (850-475-5230 for Escambia County).  If interested in issues concerning sanitary sewage overflows or septic issues, contact your county extension office, or (if in Escambia or Santa Rosa counties) visit ECUAs FOG website (Fats, Oils, and Grease) https://ecua.fl.gov/live-green/fats-oils-grease.

 

Embrace the Gulf 2020 – the nematodes

Embrace the Gulf 2020 – the nematodes

As we continue our series on marine life in the Gulf of Mexico, we also continue our articles on marine worms.  Worms are not the most charismatic creatures in the Gulf, but they are very common and play a large role on how life functions in this environment.  Roundworms are VERY common.  There are at least three phyla of them but here we will focus on one – the nematodes.

A common nematode.
Photo: University of Florida

Most nematodes are microscopic, a large one would be about 2 inches, and some beach samples have found as many as 2 million worms in 10 ft2 of sand.  So, what do we know about them?  What role, or function, do they play in the ecology of the Gulf of Mexico?

 

Well first, they are long and round – cylinder shaped.  There is a head end, but it is hard to tell which end is the head.  Round is considered a step up from being flat in that it can allow for an internal body cavity.  An internal body cavity can allow for the development of internal body organs.  Internal body organs can move large amounts of nutrients, blood, oxygen, and hormones around the body allowing the animal to become larger.  Some argue that a larger body can have advantages over smaller ones.  Some say the opposite, but either way – a large body has been successful for some creatures and an internal body cavity is needed for this.

 

That said, the nematodes do not have a complete internal body cavity.  So, they do not have a complete assortment of internal organs.  Being round reduces your efficiency in absorbing enough needed nutrients, oxygen, etc. through your skin alone and this MAY be a reason they are small.  They are very small.

 

There are free living and parasitic forms in this group.  There are at least 10,000 species of them, and they can be found not only in the marine environment, but also in freshwater and in the soil found on land.  They have played a role in the success of agriculture, infesting both crops and livestock.  Nematodes can be a big concern for farmers and gardeners.

 

The free-living forms are known to be carnivorous, feeding on smaller microscopic creatures.  They have toothed lips, and some have a sharp stylet to grab or stab their prey.  Some stylets are hollow and can “suck” their prey in.  Moving through the environment, they can consume algae, fungi, and diatoms.  Some are deposit feeders and others are decomposers.  On our farms and in our gardens, they are known to enter plants via the roots and can be found in the fruit.

The life cycle of the human hookworm.
Image: CDC

The parasitic version of nematodes has been a problem for some species.  In humans we have the hookworms and pinworms.  Dogs have their heart worms.  An interesting twist on the parasitic nematode way of life, compared to flatworms like tapeworms, is their lack of a secondary (or intermediate host).  The entire life cycle can take place in the same animal.

 

Females are larger than males and fertilizations is internal.  Males are usually “hooked” at the tail end and hold on to the females during mating.  About 50 eggs will be produced and released into the digestive tract, where they exit the animal in the feces and find new hosts either by the feces being consumed or drifting in the water column.

 

There multiple forms of parasitism in nematodes.

–          Some are ectoparasites (outside of the body) on plants.

–          Some are endoparasites in plants – some forming galls on the leaves.

–          Some infest animals but only as juveniles.

–          Some live-in plants as juveniles and animals as adults.

–          Some live-in animals as juveniles and plants as adults.

It would be fair to say that many forms of marine creatures have nematodes living either within them, or on them.  Some can be problematic and cause disease; some diseases can be quite serious.  Others play an important role in “cleaning” the ocean, filtering the sand of organic debris.  Many have heard of nematodes but know little about them.  Either good or bad, they do play roles in the ecology of the Gulf of Mexico.