The Marine Diaries

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Red Tide, Not My Vibe

Christine Lacayo

“It’s the pine trees dyeing the ocean red,” they said. 

I recently went to the beach with my family in northern Florida to celebrate my sister's birthday. But this particular trip was different. By the end of the second day, we all started noticing that everyone was coughing. Even the dogs were sneezing. My eyes were itchy and bloodshot red for most of the day.

The next morning, my dad went for a walk about 5 miles from our beach entrance.  When he arrives he sees a red patch in the ocean and so decides to ask a local about it: “It's the pine trees dyeing the ocean red,” the locals said. 

That didn’t sound right to me, so I looked up the Florida Fish and Wildlife Red Tide Current Status in our area. 

Sure enough, it was red tide. 

When waters are rife with Harmful Algal Blooms the tide turns a brownish-red, giving the phenomenon it’s fitting name. Photo: Christine Lacayo.

What exactly is Red Tide?

Red tide, or Harmful Algal Blooms (HABs), is a result of a microscopic algal bloom that can turn the ocean  reddish-brownish. This microscopic algae is known as a dinoflagellate, which are essential primary producers in the ocean’s  food web., However,  with the right conditions, they can multiply uncontrollably and suffocate everything else around them. 

One of the most common algal blooms occurs in Florida with the species, Karenia brevis. As scores of K. brevis grow and reproduce they brew a neurotoxin called brevatoxin, choking the surrounding waters and killing many fish and invertebrates in the vicinity. The subsequent decomposition of both the algae and it’s victims by microbes such as bacteria depletes the oxygen in the surrounding waters creating ‘dead zones’, suffocating many organisms and adding further stress to the environment. It can also severely disrupt the nervous system of marine mammals, birds, and turtles because of bioaccumulation of ingested contaminated prey.

A victim of the red tide. Photo: Christine Lacayo 

Where does it come from? 

There are differing views among ocean scientists about what actually causes red tide and the extent to which humans impact  the red tide is still being investigated.   We do know, however,  that it can naturally occur when rivers and streams flood, carrying an excess amount of nutrient-rich soils into the ocean.  Additionally, It can  be triggered as a result of anthropogenic activities such as  when fertilizer from agriculture, livestock feces, pollution, and sewer runoff all find their way into the ocean. What's more is that algae blooms tend to thrive with warmer ocean temperatures, low salinity content, and wind can all increase the size of a red tide bloom. 

A study investigating  the responses of K. brevis to climate change found that although neither higher carbon dioxide concentrations nor higher temperatures influenced brevetoxin production per cell, under predicted future climate conditions K. brevis blooms do have the potential to increase in concentration, posing an increased risk for our ecosystem and human health.

Why should I care? 

HABs not only cause serious damage to marine life in the area, but  also can seriously affect the human respiratory system, causing a scratchy throat, coughing, sneezing, and even nausea or dizziness; everything my family and I experienced on the beach.. As the waves break up the algae, the brevetoxin stored within the algae is released.  With the winds whipping over the water, it can then pick up the toxin and carry tiny droplets inland. 

Some human illnesses caused by HABs can be fatal for people who suffer from asthma or respiratory illnesses. Even eating red tide contaminated shellfish can cause Neurotoxic Shellfish Poisoning and can be very dangerous, causing abdominal pain, vomiting, and diarrhea.

It’s not just wildlife that the red tide is harmful towards; it affects people too. Photo: Unsplash 

What can I do to help?

Although the extent to which humans influence the occurrence of the red tide is still relatively unknown , it is safe to say that higher concentrations of agricultural and domestic  run-off, and pollution  are the main triggers. Nonetheless, there are a number of simple things you can do to help reduce the influx of chemicals and nutrients that enter into our waterways. 

  1. Use only natural and biodegradable cleaning and bathroom products - toxic ingredients often found in these products can easily alter the salinity and pH of our waterways.

  2. Reduce the flow of storm water by planting vegetation  and using porous materials around your outdoor surfaces such as wood, gravel, or stones. 

  3. Picking up after your pet can avoid bacteria-rich faeces from entering  our waterways.

  4. If you live on a farm, practice sustainable agricultural methods to reduce your runoff such as permaculture and biodynamic farming. 

A significant amount of research is still needed in order to understand and predict the causes of Harmful Algae Blooms along our coasts, but you can do your part by consuming and purchasing consciously. 

Access Florida Red Tide information where data is collected weekly from areas that experience frequent outbreaks.. This database allows people to stay safe and help make decisions regarding their beach activities and vacations.


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