Hands Off Point Peron

DISAPPEARING SEAGRASS 🌱🌊🌱
Why are the seagrass meadows in Cockburn Sound, Shoalwater Bay and Warnbro Sound disappearing?

There are many probable reasons including ocean pollution from industry, waste water disposal from the Pt Peron pipeline, and stormwater runoff from the land; dragging ship and boat anchors tearing up seagrass; ocean storms; sedimentation from dredging and naturally shifting sands; and possibly seagrass diseases.

Warmer ocean waters from climate change, in the form of marine heatwaves and gradual and longer-term ocean warming, also kills seagrass. While higher temperatures can affect the seagrass directly, ecologists from the Universities of Sydney and New South Wales have recently identified an indirect impact related to the microbial content of the sediment that the seagrass grows in.

Ocean warming can shape sediment microbial communities in ways that suppress seagrass performance. Higher temperatures favour sulphide-producing bacteria in the sediment and sulphide is toxic to seagrass roots, potentially suppressing seagrass growth and increasing the risk of seagrass death.

It's a clear demonstration that to fully understand the impacts of climate change on marine ecosystems, we need to investigate what happens microbially and on the ocean bed, as well as at higher trophic levels.

Warming seas can threaten the hidden relationship that supports seagrass meadows Seagrasses are often overlooked, but they are among the most important coastal habitats on Earth.

TINY CRITTERS OF SAFETY BAY AND SHOALWATER BEACHES: by Stephen Ambrose

PART 6: BEACH WRACK BEETLES.

Insects you would least expect to find on sandy beaches are beetles. Let's face it, most beetles have short legs and robust body shapes that are unsuited for travelling across beach sand, especially sand within the intertidal zone. But the beach wracks (piles of beach-washed seaweed and seagrass) of Safety Bay and Shoalwater Bay, and at Point Peron, and the other tiny creatures that inhabit them, make ideal habitat and food sources for at least two groups of beetles: Beach Rove Beetles (Family Staphylinidae) and Darkling (Pie-dish) Beetles (in the family Tenebrionidae).

Beach Rove Beetles have long and slender bodies which enable them to move relatively freely through entangled material in beach wracks. They are predators of fly maggots, sandhoppers, woodlice and mites that are helping to break down the beach-washed seaweed and seagrass. They also consume fungi growing in the beach wracks. The species most commonly found on local beaches is the Whiplash Beetle (Paederus meyricki, but it is possible that species in the genus Cafius also occur there (they have been recorded at Woodman Point Beach).

The pie-dish beetle has a dish-shaped body, which protects it from predators such as spiders and scorpions. Its armour allows the beetle to tilt and cover its vulnerable parts or partially bury itself, with edges flat on the ground during a predator attack. The relatively flat body shape also aids the beetle to sandboard down sand hills and climb through beach wracks. Unlike beach rove beetles, pie-dish beetles feed on decaying organic matter in the beach wracks. Hairy-backed Pie-dish Beetles (Helea perforata) have been recorded in beach wracks on local beaches, but on rare occasions you may come across species belonging to the genus Sympetes.

The presence of these species demonstrates that communities of terrestrial invertebrates within beach wracks on beaches in and around Safety Bay are relatively complex in structure. All species interact with each other and help regulate the rates at which beach-washed seaweed and seagrass are broken down and the nutrients are returned to the marine environment.

More information on beach rove beetles:
https://www.inaturalist.org/taxa/132026-Paederus

More information on pie-dish beetles:
https://www.inaturalist.org/taxa/855021-Helea-perforata

Whiplash Beetles (Genus Paederus) Paederus is a genus of small beetles of the family Staphylinidae ('rove beetles'). With 622 valid species assigned by 1987 to the subtribe Paederina (Paederus and its close allies), and with all but 148 within Paederus itself, the genus is large. Due to toxins in the hemolymph of some species within...

TINY CRITTERS OF SAFETY BAY AND SHOALWATER BEACHES: by Stephen Ambrose

PART 2: SANDHOPPERS.
In Part 1 of this information series, I introduced you to springtails, a group of invertebrates that inhabit beach-washed seaweed and seagrass (beach wracks) along Safety Bay and Shoalwater Bay beaches. These are important critters that help breakdown the wracks and return nutrients back to the marine environment. Therefore, they are essential for the maintenance of a healthy Shoalwater Islands Marine Park ecosystem.

Another group of inhabitants of beach wracks are sandhoppers, also known as amphipods. They also have the same ecological roles and importance as springtails.

Sandhoppers are minute crustaceans with a laterally-compressed body, they lack a carapace, have strong legs, and large front claws. There are many different species, typically ranging in length from 10 to 20 mm. Like springtails, they can spring short distances into the air, but differ in the way this is achieved. While a springtail has a spring-like appendage tucked under its body which it flexes, the sandhopper leaps using a powerful, sudden extension of the body, by rapidly flicking its tail from a tucked-under position.

Sandhoppers feed on rotting seaweed and seagrass and need a constantly-moist environment. As the beach wracks dry out, they move onto the next patch of beach-washed seaweed and seagrass. They are among the most abundant invertebrate in and under beach wracks, which provide them with food, moisture and shelter. Under optimal conditions they can account for 90% of all invertebrates in beach-washed seaweed and seagrass. They are also an important source of food for small shorebirds, more terrestrial bird species such as swallows and pipits, and intertidal invertebrates such as slaters (isopods) and small crabs.

The most common sandhopper species on the beaches at Shoalwater Bay and Safety Bay is Talorchestia pravidactyla (unfortunately, it does not have a common name). It has a widespread distribution, found along most of Australia's coastline, wherever there are beach wracks.

More information about sandhoppers:

Sandhoppers and Landhoppers (Family Talitridae) Talitridae is a family of amphipods. Terrestrial species are often referred to as landhoppers and beach dwellers are called sandhoppers or sand fleas. The name sand flea is misleading, though, because these talitrid amphipods do not bite people. (Source: Wikipedia, '', https://en.wikipedia.org/wiki/...