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New Jersey Scuba Diving

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New Jersey Scuba Diving

Seaweeds & Plants

Algae & Plants

In our waters, plants and algae are found only in shallow water where sufficient light can penetrate for photosynthesis. It would be unusual to find algae below 10-20 ft, so our wrecks and reefs, despite the profusion of attached organisms, are actually devoid of plant life! Of course, that is completely neglecting the microscopic algal plankton that is so profuse in our waters and so lacking in the clear water of the tropics.

Algae lack the complex structures of true plants: roots, stems, and true leaves. Some algae have a holdfast which resembles a root, and they may superficially resemble higher plants, but their internal structure is completely different. Algae vary from the microscopic single-celled organisms that form the base of the marine food chain to the gigantic northern kelps. Unlike higher plants, not all algae have green chlorophyll; shades of red, purple, yellow, and brown are also found. All types of algae are represented in freshwater as well.


A garden of green and brown algae grows on a shallow rock.
Enteromorpha ( Hollow Green Weed ) and Fucus ( Rockweed )


Green Algae

Seaweeds & Plants


Cladophera


Ulva or Sea Lettuce


Enteromorpha or Hollow Green Weed

Green algae take many forms, some of which superficially resemble grass and other plants. Cladophora grows in tufts 3"-12" in size. Sea Lettuce - Ulva lactuca - is a green algae that grows in large sheets up to 36" like tissue paper. Small specimens are attached, but large ones are usually found drifting. It is edible, and extremely common in protected waters. Enteromorpha algae superficially resembles eelgrass, and like eelgrass may also grow in thick beds.

Codium, also known as Green Fleece or Dead Man's Fingers, ( right ) is a pest species introduced from Europe that is steadily spreading outward along the coast from Long Island. It actually originates in Japan, and is spreading around the world.

The fronds are thick and spongy, and the entire "bush" may grow up to 36" although it is usually smaller. This algae is sometimes seen offshore at depths where it could not possibly have grown. My guess is that it was swept out from shallow water in a storm, carrying whatever stone or object it grew on along with it, and settled on the bottom, where it will eventually die in the darkness.


Green Fleece Algae Codium, with ubiquitous Cunner

Sea lettuce, a kind of green algae that conservationists say is a critical food supply for some wildfowl, covers large sections of the Navesink River Rumson. Research scientist Clyde L. MacKenzie Jr. (above) shows the difference between Navesink River sediment taken from under a patch of sea lettuce (left), which he said contains only dead, rotting matter; and mud taken from another section (right), which he said is teeming with life. Mackenzie says some of the sea lettuce in local rivers should be removed because it kills everything beneath it, including soft-shell crabs.

By TODD B. BATES
ENVIRONMENTAL WRITER
STAFF PHOTOS: THOMAS P. COSTELLO

RUMSON - Clyde L. MacKenzie Jr. grabbed two handfuls of sediment in the shallows of the scenic Navesink River off Navesink Avenue. One of the samples, taken from beneath a patch of sea lettuce, was almost black, full of rotting matter and virtually devoid of life, according to MacKenzie, of the National Marine Fisheries Service on Sandy Hook. The other sample, removed from an area free of sea lettuce, had brown scum on the surface that was "full of live animals, " including tiny worms and shrimp-like creatures, the habitat biologist said.

MacKenzie wants some of the prolific seaweed, which he said has increased in the Navesink and Shrewsbury rivers this year, to be removed. Sea lettuce helped kill soft-shell clams in the rivers in the mid-1990s and has helped prevent them from making a comeback, according to MacKenzie. "It's killed everything along the shore" in calm areas of the two rivers, he said. "It disturbs me." But conservationists said sea lettuce is food for Atlantic brant and other birds, and they'd like to see more research on its use by animals, the impact of harvesting it and the need to control it.


"It's killed everything along the (river) shore."

- Clyde L Mackenzie Jr. of the National Marine Fisheries Service on Sandy Hook.


"It creates a special type of habitat and is a food source for waterfowl, invertebrates, and fish."

- Amy Cradic, spokeswoman for the New Jersey Department of Environmental Protection.

Food for wintering birds

Eric Stiles, vice president of conservation for the New Jersey Audubon Society, said sea lettuce is "an absolutely critical food supp1y" for wintering brant. Stiles said he would need to "understand a lot more" about MacKenzie's proposal before reacting to it. "It depends on the scope and magnitude of what is being proposed, what (are) the primary and secondary ecological impacts beyond even the avian species, and really looking at the science behind the conclusion that it needs to be controlled, " he said.

Amy Cradic, a spokeswoman for the state Department of Environmental Protection, said the DEP has "received no formal proposal for removal" of the plant. "Basically, removing sea lettuce is not an option being considered by the department at this time, " Cradic said. "It creates a special type of habitat and is a food source for waterfowl, invertebrates and fish."

Ulva lactuca, the Latin name for this species of sea lettuce, has become a problem in North America and Europe over the past 30 years as levels of nutrients have increased in estuaries, MacKenzie has said. And sea lettuce, a bright green form of algae, has overrun shallow areas in the Navesink and Shrewsbury rivers in recent years, according to MacKenzie, 72, of Fair Haven.

Estuaries, where fresh water from rivers meets salt water from the ocean, are key nurseries for marine life. Sea lettuce flourishes in areas with lots of nitrogen and phosphorus, which. can come from fertilizers, street runoff and other sources, experts say. Such nutrients fuel the growth of algae. "Up to 30 to 40 years ago, for thousands (of years) there was very little sea lettuce, " MacKenzie said.

Part of the food chain

Sea lettuce affects the food chain, be. ginning With plankton and including killifish, a foundation of the marine food chain, and likely the fish that eat killifish, according to MacKenzie. Sea lettuce kills everything beneath it, MacKenzie said. And nothing grows its surface because it produces small amounts of toxins, repelling plants or animals that might attach to it, such as barnacles, small mollusks, oysters and other algae, he has said. MacKenzie said he believes that this year's rainfall, which led to lower salt levels in the two rivers, has resulted in a lot more sea lettuce than during last year's drought. Still, "I don't know what drives it, to be honest with you, " he said. "It's just my guess."

MacKenzie said he saw much larger amounts of sea lettuce in the mid-1990s, when the seaweed covered and killed many soft-shell clams in the Navesink and Shrewsbury rivers in 1994. A heat wave the next year killed the rest. Although he's sure sea lettuce has some benefits, "overall, it does a lot of harm, " MacKenzie said. Using nets to haul sea lettuce out of the water twice a summer and then letting it dry and decay on the shoreline would be one way to control it, according to MacKenzie. There also will be "enough of it to grow back, " he said.

Scott Barnes, a senior naturalist at the New Jersey Audubon Society's Sandy Hook Bird Observatory, said he's seen both Atlantic brant and greater scaup eat sea lettuce. Brant are much smaller than their close cousins, Canada geese, and greater scaup are small diving ducks, according to officials. The area that includes Raritan Bay and the Navesink and Shrewsbury rivers has "arguably the largest concentration of greater scaup on the East Coast, " Barnes said, with 20,000 to 50,000 of them spending their winters there. Thousands of brant also overwinter in the area. Frequently, ducks will pop to the surface with sea lettuce in their mouths and herring gulls will try to steal the lettuce, Barnes said.

More research advocated

Andrew J. Willner, New York-New Jersey Baykeeper, an affiliate of the Sandy Hook-based American Littoral Society, said "we've been finding that some creatures have sort of adapted" to sea lettuce, including brant. The seaweed is "unsightly and it's not fun to walk through, but with the lack of eelgrass and other kinds of vegetation, perhaps it is taking up some of that niche, " Willner said.

Sea lettuce could be used as a fertilizer, eliminating some of the chemicals people put on their gardens and, lawns, and composting it would be "a great thing, " Willner said. "I would also be very careful, and some research should be done on what animals are using" sea lettuce, he said. "We may want to investigate that a little further to see if there was some reason it should not be harvested."

Beatrice Sena, Fair Haven Borough Council president, began using sea lettuce as a plant fertilizer years ago. This year, she planted tomatoes in a container with decomposing sea lettuce to see how her plants would do without other fertilizers being added, Sena said. "I must tell you, they are extraordinary, " she said. "They're healthy plants. The fruit that I have is blemish-free and quite large and I don't know if it's attributable to the variety of tomato I use, with the disease-resistance factor within the plant. However, I still swear by my sea lettuce, although I didn't add any this year."

Sena said, "I still would love to see benefits from this organic compound, especially if Mr. MacKenzie feels that it's grown to an extent it could be detrimental to the other natural biological life that's there. "I would love for it to be utilized, as long as it was environmentally sound to do so and as long as it was cost-effective to do so, " she said. "I hate to see anything wasted."

Reprinted from the Asbury Park Press, Sunday Sept 14, 2003
Todd B. Bates: (732) 643-4237 or tbates@app.com


Red & Purple Algae

Seaweeds & Plants

Red algae actually vary in color from straw-yellow to deep-purple or black in appearance.


Agardh's Red Weed - Agardhiella subulata is very common and grows in tufts and clumps to about 12" in sunny shallow areas.



A common purple type known as Dasya or Chenille Weed.


Laver or Porphyra ( above ) is similar to Ulva in many ways, although unrelated. It grows interspersed with Ulva in shallow sunny areas, and like Ulva, it is edible.



Yellow & Brown Algae

Seaweeds & Plants

Pictured is a type commonly known as Rockweed ( Fucus vesiculosus, or Bladderwrack ) a tough northern type, adapted to the rocky shores of New England. However, it is more than happy to grow on jetties and pilings wherever it finds them, and is quite common in the inlets around New Jersey. Like many other forms of algae, this one has gas bladders for flotation.

Sargassum or Gulfweed is another brown algae that is brought up in the Gulf Stream in late summer / early fall. East winds blow it in to where it may be found in small to large clumps floating in the surface waters around the offshore wrecks. Scoop up a clump in a goody bag and dump it in a bucket of water. You may find a number of interesting tropical fishes and crustaceans. A native species also occurs as far north as eastern Long Island and southern new England.

Brown algae also includes microscopic diatoms ( below ), one of the most important types of microscopic plankton, as well as kelp, on of the largest living organisms. Unfortunately, the waters around New Jersey get too warm in the summer for true kelp to survive. Many brown algae are capable of thriving in lower-light conditions than green or red algae.


My best guess is that these one-inch balls of goo are a brown algae known
as Sea Potatoes. I am told that is a bad guess, and that they are probably
something else entirely, not even algae. If anyone knows, please share.


Diatoms ( Chaetoceros spp. )


Blue-Green Algae

Seaweeds & Plants

Most blue-green algae are inconspicuous, forming slimes or velvety coverings on any available surface. Some blue-green algae, not all of which are blue-green in color, are capable of surviving in extreme conditions that kill most other forms of life. Some give off toxins that are harmful or fatal to other forms.

Although it may seem a minor difference between green and blue-green, the names belie a tremendous difference in biology - these are actually photosynthetic Bacteria.


Eelgrass ( Seagrass )

Seaweeds & Plants

Zostera marina

Size: to 36"

Seagrass: Nature's Nursery

By Michael Celestino,
Fisheries Biologist,
Bureau of Marine Fisheries

Seagrasses are a group of approximately 50 species of vascular plants that complete their entire life cycle fully submerged in the marine environment. The most common and ecologically important seagrasses in New Jersey are eelgrass ( Zostera marina ) and widgeon grass ( Ruppia maritima ). Widgeon grass, however, is actually a fresh / brackish water plant with extreme salinity tolerance, and is therefore sometimes not classified as a "true" marine seagrass.

Nevertheless, both eelgrass and widgeon grass are true flowering plants with subsurface roots and root-like rhizomes that extend through unconsolidated sediments varying from pure, firm sand to fine, soft muds. Seagrasses are found worldwide in shallow coastal waters and can migrate from year to year or even from season to season within suitable habitat. In New Jersey they are most prevalent in the shallow ( <5' ) portions of the Navesink, Shrewsbury, Manasquan and Metedeconk Rivers and in Barnegat, Manahawkin and Little Egg Harbor Bays.

Seagrasses are sometimes considered a nuisance by boaters and waterfront property owners where the vegetation can interfere with boat engines and tends to accumulate in piles of detritus on beaches. However, the ecological benefits provided by seagrasses can be shown to far outweigh any "inconveniences" to recreation or leisure.

Specifically, seagrass communities help stabilize sediments, dampen wave energy, buffer shorelines from erosion and improve/enhance water clarity and quality. Seagrasses also serve an especially important role in the production of fishery resources. Extensive data indicate that seagrass meadows provide a high quality habitat for fishes and invertebrates. For example, the physical structure provided by seagrass beds along with associated epiphytes ( attached algae ) and drift algae enhances the habitat for invertebrates by providing attachment sites and refuge from predators. In addition, the rhizome layer may protect shallow dwelling hard clams, whereas on exposed sand flats, whelks and other predators easily detect and capture clams. Similarly, seagrasses serve as nursery areas for juvenile and subadult finfish, providing abundant and varied food resources as well as refuge and protection from larger predators. Many fishery organisms occur in seagrass beds at some stage in their life history, including juveniles of open water coastal fisheries ( menhaden, summer flounder, bluefish, Atlantic croaker, Pacific herring, spot, weakfish, silver perch, mullet, and blue crabs. )

While juvenile fish can utilize other types of shelter, the bulk of shelter habitat in many estuaries is provided by seagrasses. Its loss, therefore, will likely lead to declines in juvenile fish recruitment. Entire fisheries have completely crashed as a result of eelgrass loss. This was dramatically illustrated in the 1930's when a disease epidemic virtually eliminated eelgrass from the entire eastern US coastline. Scallops, clams, oysters, crabs and many species of fish suffered dramatic declines from the loss of productive habitat with the concomitant siltation, creation of mudflats and erosion that occurred because eelgrass no longer anchored bottom sediments.

While the catastrophic loss of eelgrass in the 1930's may have resulted from a very unique event, any activity that degrades seagrass habitat, reduces light penetration, or physically destroys seagrass will limit the plant's growth and survival. At the extreme, chronic levels of these disturbances could ultimately lead to the severe declines experienced in the 1930's.

Seagrass meadows are often subject to tremendous damage by even the most seemingly "innocent" human activities. For example, walking through seagrass meadows can drive shoots deep into the muddy bottom, which often kills them. More dramatic and systemic declines stem from decreased water clarity resulting from boat propeller wash and vessel wakes that can dislodge sediments and even uproot seagrasses. This is most commonly seen when vessels operate in or have wakes that reach shallow waters. The resuspension of sediments through turbulence generated by vessels can greatly reduce light penetration which in turn limits the distribution of suitable habitat for seagrasses.

Similarly, shading from docks and other structures also leads to seagrass loss. Light penetration and availability are thought to be the most important factors affecting and regulating the density, productivity, growth and survival of seagrasses. In fact, reductions in the amount of light reaching seagrass blades is widely considered the major reason for seagrass decline in coastal waters.

Likewise, boat propeller scarring ( severing of seagrass leaves, roots and/or rhizomes with a boat propeller ) resulting from boaters taking "shortcuts", misjudging water depths or grounding are particularly destructive to seagrasses. Slow recovery ( up to 10 years or more ) from scarring, coupled with increased scarring rates, elevates the rate of cumulative loss of seagrasses and their habitat values.

Losses of seagrass due to chronic disturbances are difficult to reverse because the sediment stabilization and water column filtration benefits of the seagrass cover have been lost. Sediments are therefore easily re-suspended, adding to the turbidity of the water column and decreasing the likelihood of effective restoration.

Even if the affected areas resulting from any of these activities are relatively small compared to the size of the seagrass bed, these impacts fragment and disrupt the beds, making the entire habitat more susceptible to damage from other stresses like meteorological events such as storms. These and other disturbances may be acting together to result in large-scale declines in seagrass distribution.

Eelgrass is an important part of our coastal ecosystem and its health is an indicator of the overall health of bays and estuaries. The longevity of seagrass meadows, coupled with their complex physical structure and high rates of primary production, enable them to form the base of an abundant and diverse faunal community. For many fishery organisms there is no one reason why they should be attracted to seagrass meadows, but rather there are a combination of features providing many essential resources. The benefits provided by seagrass systems are furnished free of charge, provided we act responsibly and protect this valuable resource.

References:
Brown-Peterson, N.J. et al., 1993; Burdick, D.N. & F.T. Short, 1998; Fonseca, MS. et al., 1979; Fonseca, M.S., W J. Kenworthy & G.W. Thayer, 1992; Good, R.E. et al., 1978; Kenworthy, Wi. & D.E. Haunert (eds.), 1991; Lockwood, J.C., 1990; Lockwood, J.C., 1991; New Jersey Administrative Code Rules on Coastal Zone Management, 1994; Sargent, F.J. Ct al., 1995; Short, F.T., 1988; Stevenson, J.C & L.W. Stayer, 1990

This article first appeared in New Jersey Fish & Wildlife Digest - 2000 Marine edition


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I make no claim as to the accuracy, validity, or appropriateness of any information found in this website. I will not be responsible for the consequences of any action that is based upon information found here. Scuba diving is an adventure sport, and as always, you alone are responsible for your own safety and well being.

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