Sponges: Glue of the reef

Sponges fragments
Bobbie Renfro with red sponge fragments

A variety of environmental threats hang over scuba attraction the Florida Keys, but a team of dedicated divers are doing their bit to shift the balance by learning what it is that keeps sponges happy. Report and photos by JOHN CHRISTOPHER FINE.

Also read: Deep doodoo: Diver’s-eye view of a Florida problem

“Sponges are the glue of the reef. They hold those rocks together, keep them solidified,” says Bobbie Renfro. This native of Austin saw salt water for the first time when she took a University of Texas course that brought students to the Gulf of Mexico. 

Also read: Sea-sponges hid shocking thermal secret

That experience resulted in a career change. Bobbie earnt her masters degree in biology from Florida State University, where she is now a doctoral candidate studying sponges off Islamorada in the Florida Keys.

Also read: Tales of diving’s true pioneers

“We’re doing research into how nutrients in the ocean affect sponge growth,” she tells me. “We’re trying to determine whether sponges grow faster in nutrient-rich environments, or whether there is increased mortality. 

“We don’t yet know whether run-offs of fertiliser, rich in nutrients like dissolved nitrogen, are good or bad for sponges. We take water samples and analyse them for nitrogen, phosphates and dissolved organic carbons.” 

Glue – divers in Florida Keys
Divers at work off Islamadora

The researchers have been taking water samples inside Hawk’s Channel, where water from Florida Bay is pulled in.

Nutrient levels from agricultural run-off have created widespread pollution and marine-life mortality in the bay, and it also enters protected sanctuary areas of the Florida Keys.

“Sponges do not do well in captivity,” says Bobbie. “We do everything in a natural environment. We take small samples from healthy sponges and move them into Hawk’s Channel.

We take sponge samples from Hawk’s Channel and move them out into the open ocean. We want to see if higher nutrients in Hawk’s Channel adversely affect them. 

“This study will continue this summer and next. Hypothesis is species-dependent – some may do well in higher nutrient levels, others may not.”

Green finger

Bobbie is working with Mike Goldberg, president of Key Dives in Islamorada and co-founder of I.Care (Islamorada Conservation & Restoration Education), a non-profit foundation dedicated to coral-reef conservation, and Dr Kylie Smith, who is attached to Mote Marine Laboratory and Clemson University. 

I.Care interns and volunteer divers accompany Bobbie and Mike on dives to plant sponges on reefs offshore from Islamorada.

So far I.Care and University of Florida researchers have worked with three species: the red sponge Amphimedon compressa, green finger sponges Iotrochota birtulata and the rope sponge Aplysina cauliformis

First take your sponge: Bobbie Renfro at work
First take your sponge: Bobbie Renfro at work

“What we know for sure when we move sponges into mangroves, where there is a naturally higher nutrient level, is that they grow faster,” Bobbie tells me. “The question is, do human-based nutrients do the same? 

“The Florida Wildlife Commission has been restoring sponges on the bay side. Sponges in general are filter-feeders – they suck in water and remove the smallest type of plankton.

These organisms have caused blooms when we have high nutrient levels in the water. Sponges help to clear the water.” 

Nature’s balance

The importance of nature’s balance has yet to be fully understood. Rampant development and agricultural activities continue in Florida, the third most populous state in the USA with about 22 million people. 

It needs to keep sugar cane growing and citrus groves producing; to maintain golf courses, lawns and gardens; to support cattle in a state that is a feed-lot for American-produced beef, fattened in Florida’s good weather and made heavy by use of hormones and antibiotics, their waste adding to the groundwater run-offs as well as evaporation that falls back into the ocean every time it rains.

All this has required the fertiliser, herbicides and insecticides that destroy coral and marine life. 

In the 1970s, live coral coverage in the Florida Keys was about 70%. Today researchers judge it to be 3-5%. Algae that thrive in high ocean nutrient levels have bloomed. As algae dies and sinks to the seabed, it chokes and covers corals.

Team briefing
Team briefing
Amphimedon compresa red sponge as a diver would recognise itRed coral
How divers hope to see sponges – Amphimedon compresa red sponge (Nick Hobgood)

Various weather events – particularly Hurricane Irma, which devastated the Florida Keys in September 2017 – have scoured or scraped sponges off the reefs, says Bobbie. “Working with I.Care, we can let divers who want to help the reef get involved. It’s working well. 

“We are restoring the reef, and spreading information about the importance that each organism on the reef has to the overall health of the environment.

“People will come to understand the whole community of the reef system and feel stewardship for it,” predicts this dedicated researcher.

“Our relationship with the natural world is important if future generations are to enjoy a healthy reef environment that supports food and marine life, and tames hurricane-force waves, which have 97% of their energy broken up and 84% of their height decreased by offshore reefs.” 

“Having witnessed the devastation caused by Hurricane Irma, imagine what would have happened without the stopping power of this third-largest barrier reef in the world?” Find out more about I.Care or explore Key Dives.

John Christopher Fine

John Christopher Fine is a marine biologist and has dived shipwrecks all over the world. He is a Master Scuba Instructor, Instructor Trainer and the author of some 25 fiction and non-fiction books on a wide range of themes.

Also on Divernet: Secret Upwardly Mobile Life of Sponges, First Self-Lit Sponges Identified, Viruses Bow To Killer Sponges

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@timpell49
#AskMark Mark great video love your content I recently had my cylinder hydro tested it was filled with air how long can you keep the air in the cylinder before you use it .Also dive shop can drain the air and fill with nitrox?
#scuba #scubadiving #scubadiver

Become a fan: https://www.scubadivermag.com/join

GEAR PURCHASES: https://www.scubadivermag.com/affiliate/dive-gear

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The information in this video is not intended nor implied to be a substitute for professional SCUBA Training or recommendations for every manufacturer. All content, including text, graphics, images, and information, contained in this video is for general information purposes only and does not replace training from a qualified Dive Instructor or specific requirements from equipment manufacturers.

YouTube Video UEw2X2VCMS1KYWdWbXFQSGV1YW84WVRHb2pFNkl3WlRSZS41ODI2RjhGOTVBODI2NDE5

How Long Can You Keep Air in a Cylinder? #AskMark #scubadiving

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00:00 Introduction
01:35 Scuba.com Ad
02:35 Duikvaker
03:15 EUDI
04:23 DRT
05:04 GO Diving Show UK
06:24 ADEX OZTek
07:06 Mediterranean
07:34 ADEX
08:21 TDEX
08:51 Scuba Show
09:36 MIDE
10:06 GO Diving ANZ
11:09 Diving Talks
11:58 DEMA

Full List of Dive Shows with Links:
https://divernet.com/scuba-diving/your-worldwide-dive-show-guide-for-2025/

JANUARY 18-26: Boot Düsseldorf (International Boat Show)
FEBRUARY 1-2: Duikvaker
FEBRUARY 21-23: European Dive Show (EUDI)
FEBRUARY 21-23: Diving Resort Travel (DRT) Show, Malaysia
MARCH 1-2: GO Diving Show (The UK Dive Show)
MARCH 15-16: ADEX Ocean Festival / OZTek Australia
MARCH 28-30: Mediterranean Diving Show
APRIL 4-6: Asia Dive Expo (ADEX)
MAY 22-25: Thailand Dive Expo (TDEX)
MAY 31 – JUNE 1: Scuba Show
JUNE 13-15: Malaysia International Dive Expo (MIDE)
SEPTEMBER 6-7: GO Diving ANZ Show
OCTOBER 17-19: Diving Talks
NOVEMBER 11-14: DEMA Show

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We partner with https://www.scuba.com and https://www.mikesdivestore.com for all your gear essentials. Consider using the affiliate link above to support the channel.

The information in this video is not intended nor implied to be a substitute for professional SCUBA Training or recommendations for every manufacturer. All content, including text, graphics, images, and information, contained in this video is for general information purposes only and does not replace training from a qualified Dive Instructor or specific requirements from equipment manufacturers.
00:00 Introduction
01:35 Scuba.com Ad
02:35 Duikvaker
03:15 EUDI
04:23 DRT
05:04 GO Diving Show UK
06:24 ADEX OZTek
07:06 Mediterranean
07:34 ADEX
08:21 TDEX
08:51 Scuba Show
09:36 MIDE
10:06 GO Diving ANZ
11:09 Diving Talks
11:58 DEMA

YouTube Video UEw2X2VCMS1KYWdWbXFQSGV1YW84WVRHb2pFNkl3WlRSZS43OTNDNTk0OUNGMDA1MUNG

Upcoming Dive Shows in 2025 #scubadiving #diveshow

US diver Barrington Scott has set a verified Guinness World Record for the fastest time to scuba dive across all seven continents.Cartagena City Council says it is preparing to tighten access to the Cueva del Agua (Water Cave) system in southern Spain, following the death of a 37-year-old female diver there on 18 January. And an underwater habitat builder has just extended the record for longest time spent submerged. 

https://divernet.com/scuba-news/scuba-dash-across-7-continents-brings-world-record/
https://divernet.com/scuba-news/health-safety/spanish-cave-divers-death-prompts-calls-for-controls/ 
https://www.kentucky.com/news/nation-world/national/article299289964.html
https://divernet.com/scuba-news/pod-builder-completes-120-days-under-sea/

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Website: https://www.scubadivermag.com ➡️ Scuba Diving, Underwater Photography, Hints & Advice, Scuba Gear Reviews
Website: https://www.divernet.com ➡️ Scuba News, Underwater Photography, Hints & Advice, Travel Reports
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We partner with https://www.scuba.com and https://www.mikesdivestore.com for all your gear essentials. Consider using the affiliate link above to support the channel.

The information in this video is not intended nor implied to be a substitute for professional SCUBA Training or recommendations for every manufacturer. All content, including text, graphics, images, and information, contained in this video is for general information purposes only and does not replace training from a qualified Dive Instructor or specific requirements from equipment manufacturers.

US diver Barrington Scott has set a verified Guinness World Record for the fastest time to scuba dive across all seven continents.Cartagena City Council says it is preparing to tighten access to the Cueva del Agua (Water Cave) system in southern Spain, following the death of a 37-year-old female diver there on 18 January. And an underwater habitat builder has just extended the record for longest time spent submerged.

https://divernet.com/scuba-news/scuba-dash-across-7-continents-brings-world-record/
https://divernet.com/scuba-news/health-safety/spanish-cave-divers-death-prompts-calls-for-controls/
https://www.kentucky.com/news/nation-world/national/article299289964.html
https://divernet.com/scuba-news/pod-builder-completes-120-days-under-sea/

#scuba #scubadiving #scubadiver

Become a fan: https://www.scubadivermag.com/join

GEAR PURCHASES: https://www.scubadivermag.com/affiliate/dive-gear

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OUR WEBSITES

Website: https://www.scubadivermag.com ➡️ Scuba Diving, Underwater Photography, Hints & Advice, Scuba Gear Reviews
Website: https://www.divernet.com ➡️ Scuba News, Underwater Photography, Hints & Advice, Travel Reports
Website: https://www.godivingshow.com ➡️ The Only Dive Show in the United Kingdom
Website: https://www.rorkmedia.com ➡️ For advertising within our brands
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We partner with https://www.scuba.com and https://www.mikesdivestore.com for all your gear essentials. Consider using the affiliate link above to support the channel.

The information in this video is not intended nor implied to be a substitute for professional SCUBA Training or recommendations for every manufacturer. All content, including text, graphics, images, and information, contained in this video is for general information purposes only and does not replace training from a qualified Dive Instructor or specific requirements from equipment manufacturers.

YouTube Video UEw2X2VCMS1KYWdWbXFQSGV1YW84WVRHb2pFNkl3WlRSZS4yNkZBOTQyMkYxQkQyMzc2

Spanish Cave Closed After Fatality #scuba #podcast #news

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